Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:

 1) BBR TCP congestion control, from Neal Cardwell, Yuchung Cheng and
    co. at Google. https://lwn.net/Articles/701165/

 2) Do TCP Small Queues for retransmits, from Eric Dumazet.

 3) Support collect_md mode for all IPV4 and IPV6 tunnels, from Alexei
    Starovoitov.

 4) Allow cls_flower to classify packets in ip tunnels, from Amir Vadai.

 5) Support DSA tagging in older mv88e6xxx switches, from Andrew Lunn.

 6) Support GMAC protocol in iwlwifi mwm, from Ayala Beker.

 7) Support ndo_poll_controller in mlx5, from Calvin Owens.

 8) Move VRF processing to an output hook and allow l3mdev to be
    loopback, from David Ahern.

 9) Support SOCK_DESTROY for UDP sockets. Also from David Ahern.

10) Congestion control in RXRPC, from David Howells.

11) Support geneve RX offload in ixgbe, from Emil Tantilov.

12) When hitting pressure for new incoming TCP data SKBs, perform a
    partial rathern than a full purge of the OFO queue (which could be
    huge). From Eric Dumazet.

13) Convert XFRM state and policy lookups to RCU, from Florian Westphal.

14) Support RX network flow classification to igb, from Gangfeng Huang.

15) Hardware offloading of eBPF in nfp driver, from Jakub Kicinski.

16) New skbmod packet action, from Jamal Hadi Salim.

17) Remove some inefficiencies in snmp proc output, from Jia He.

18) Add FIB notifications to properly propagate route changes to
    hardware which is doing forwarding offloading. From Jiri Pirko.

19) New dsa driver for qca8xxx chips, from John Crispin.

20) Implement RFC7559 ipv6 router solicitation backoff, from Maciej
    Żenczykowski.

21) Add L3 mode to ipvlan, from Mahesh Bandewar.

22) Support 802.1ad in mlx4, from Moshe Shemesh.

23) Support hardware LRO in mediatek driver, from Nelson Chang.

24) Add TC offloading to mlx5, from Or Gerlitz.

25) Convert various drivers to ethtool ksettings interfaces, from
    Philippe Reynes.

26) TX max rate limiting for cxgb4, from Rahul Lakkireddy.

27) NAPI support for ath10k, from Rajkumar Manoharan.

28) Support XDP in mlx5, from Rana Shahout and Saeed Mahameed.

29) UDP replicast support in TIPC, from Richard Alpe.

30) Per-queue statistics for qed driver, from Sudarsana Reddy Kalluru.

31) Support BQL in thunderx driver, from Sunil Goutham.

32) TSO support in alx driver, from Tobias Regnery.

33) Add stream parser engine and use it in kcm.

34) Support async DHCP replies in ipconfig module, from Uwe
    Kleine-König.

35) DSA port fast aging for mv88e6xxx driver, from Vivien Didelot.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1715 commits)
  mlxsw: switchx2: Fix misuse of hard_header_len
  mlxsw: spectrum: Fix misuse of hard_header_len
  net/faraday: Stop NCSI device on shutdown
  net/ncsi: Introduce ncsi_stop_dev()
  net/ncsi: Rework the channel monitoring
  net/ncsi: Allow to extend NCSI request properties
  net/ncsi: Rework request index allocation
  net/ncsi: Don't probe on the reserved channel ID (0x1f)
  net/ncsi: Introduce NCSI_RESERVED_CHANNEL
  net/ncsi: Avoid unused-value build warning from ia64-linux-gcc
  net: Add netdev all_adj_list refcnt propagation to fix panic
  net: phy: Add Edge-rate driver for Microsemi PHYs.
  vmxnet3: Wake queue from reset work
  i40e: avoid NULL pointer dereference and recursive errors on early PCI error
  qed: Add RoCE ll2 & GSI support
  qed: Add support for memory registeration verbs
  qed: Add support for QP verbs
  qed: PD,PKEY and CQ verb support
  qed: Add support for RoCE hw init
  qede: Add qedr framework
  ...

27 files changed, 6026 insertions, 4434 deletions

diff --git a/net/rxrpc/Kconfig b/net/rxrpc/Kconfig
index 784c53163b7b..86f8853a038c 100644
--- a/net/rxrpc/Kconfig
+++ b/net/rxrpc/Kconfig
@@ -19,6 +19,20 @@ config AF_RXRPC
 
 	  See Documentation/networking/rxrpc.txt.
 
+config AF_RXRPC_IPV6
+	bool "IPv6 support for RxRPC"
+	depends on (IPV6 = m && AF_RXRPC = m) || (IPV6 = y && AF_RXRPC)
+	help
+	  Say Y here to allow AF_RXRPC to use IPV6 UDP as well as IPV4 UDP as
+	  its network transport.
+
+config AF_RXRPC_INJECT_LOSS
+	bool "Inject packet loss into RxRPC packet stream"
+	depends on AF_RXRPC
+	help
+	  Say Y here to inject packet loss by discarding some received and some
+	  transmitted packets.
+
 
 config AF_RXRPC_DEBUG
 	bool "RxRPC dynamic debugging"
diff --git a/net/rxrpc/Makefile b/net/rxrpc/Makefile
index 10f3f48a16a8..8fc6ea347182 100644
--- a/net/rxrpc/Makefile
+++ b/net/rxrpc/Makefile
@@ -22,6 +22,7 @@ af-rxrpc-y := \
 	peer_object.o \
 	recvmsg.o \
 	security.o \
+	sendmsg.o \
 	skbuff.o \
 	utils.o
 
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 88effadd4b16..44c9c2b0b190 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -16,12 +16,14 @@
 #include <linux/net.h>
 #include <linux/slab.h>
 #include <linux/skbuff.h>
+#include <linux/random.h>
 #include <linux/poll.h>
 #include <linux/proc_fs.h>
 #include <linux/key-type.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
+#define CREATE_TRACE_POINTS
 #include "ar-internal.h"
 
 MODULE_DESCRIPTION("RxRPC network protocol");
@@ -43,7 +45,7 @@ u32 rxrpc_epoch;
 atomic_t rxrpc_debug_id;
 
 /* count of skbs currently in use */
-atomic_t rxrpc_n_skbs;
+atomic_t rxrpc_n_tx_skbs, rxrpc_n_rx_skbs;
 
 struct workqueue_struct *rxrpc_workqueue;
 
@@ -104,19 +106,25 @@ static int rxrpc_validate_address(struct rxrpc_sock *rx,
 	case AF_INET:
 		if (srx->transport_len < sizeof(struct sockaddr_in))
 			return -EINVAL;
-		_debug("INET: %x @ %pI4",
-		       ntohs(srx->transport.sin.sin_port),
-		       &srx->transport.sin.sin_addr);
 		tail = offsetof(struct sockaddr_rxrpc, transport.sin.__pad);
 		break;
 
+#ifdef CONFIG_AF_RXRPC_IPV6
 	case AF_INET6:
+		if (srx->transport_len < sizeof(struct sockaddr_in6))
+			return -EINVAL;
+		tail = offsetof(struct sockaddr_rxrpc, transport) +
+			sizeof(struct sockaddr_in6);
+		break;
+#endif
+
 	default:
 		return -EAFNOSUPPORT;
 	}
 
 	if (tail < len)
 		memset((void *)srx + tail, 0, len - tail);
+	_debug("INET: %pISp", &srx->transport);
 	return 0;
 }
 
@@ -128,7 +136,8 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 	struct sockaddr_rxrpc *srx = (struct sockaddr_rxrpc *)saddr;
 	struct sock *sk = sock->sk;
 	struct rxrpc_local *local;
-	struct rxrpc_sock *rx = rxrpc_sk(sk), *prx;
+	struct rxrpc_sock *rx = rxrpc_sk(sk);
+	u16 service_id = srx->srx_service;
 	int ret;
 
 	_enter("%p,%p,%d", rx, saddr, len);
@@ -152,16 +161,13 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 		goto error_unlock;
 	}
 
-	if (rx->srx.srx_service) {
-		write_lock_bh(&local->services_lock);
-		list_for_each_entry(prx, &local->services, listen_link) {
-			if (prx->srx.srx_service == rx->srx.srx_service)
-				goto service_in_use;
-		}
-
+	if (service_id) {
+		write_lock(&local->services_lock);
+		if (rcu_access_pointer(local->service))
+			goto service_in_use;
 		rx->local = local;
-		list_add_tail(&rx->listen_link, &local->services);
-		write_unlock_bh(&local->services_lock);
+		rcu_assign_pointer(local->service, rx);
+		write_unlock(&local->services_lock);
 
 		rx->sk.sk_state = RXRPC_SERVER_BOUND;
 	} else {
@@ -174,7 +180,7 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 	return 0;
 
 service_in_use:
-	write_unlock_bh(&local->services_lock);
+	write_unlock(&local->services_lock);
 	rxrpc_put_local(local);
 	ret = -EADDRINUSE;
 error_unlock:
@@ -191,7 +197,7 @@ static int rxrpc_listen(struct socket *sock, int backlog)
 {
 	struct sock *sk = sock->sk;
 	struct rxrpc_sock *rx = rxrpc_sk(sk);
-	unsigned int max;
+	unsigned int max, old;
 	int ret;
 
 	_enter("%p,%d", rx, backlog);
@@ -210,9 +216,13 @@ static int rxrpc_listen(struct socket *sock, int backlog)
 			backlog = max;
 		else if (backlog < 0 || backlog > max)
 			break;
+		old = sk->sk_max_ack_backlog;
 		sk->sk_max_ack_backlog = backlog;
-		rx->sk.sk_state = RXRPC_SERVER_LISTENING;
-		ret = 0;
+		ret = rxrpc_service_prealloc(rx, GFP_KERNEL);
+		if (ret == 0)
+			rx->sk.sk_state = RXRPC_SERVER_LISTENING;
+		else
+			sk->sk_max_ack_backlog = old;
 		break;
 	default:
 		ret = -EBUSY;
@@ -230,6 +240,8 @@ static int rxrpc_listen(struct socket *sock, int backlog)
  * @srx: The address of the peer to contact
  * @key: The security context to use (defaults to socket setting)
  * @user_call_ID: The ID to use
+ * @gfp: The allocation constraints
+ * @notify_rx: Where to send notifications instead of socket queue
  *
  * Allow a kernel service to begin a call on the nominated socket.  This just
  * sets up all the internal tracking structures and allocates connection and
@@ -242,7 +254,8 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
 					   struct sockaddr_rxrpc *srx,
 					   struct key *key,
 					   unsigned long user_call_ID,
-					   gfp_t gfp)
+					   gfp_t gfp,
+					   rxrpc_notify_rx_t notify_rx)
 {
 	struct rxrpc_conn_parameters cp;
 	struct rxrpc_call *call;
@@ -269,6 +282,8 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
 	cp.exclusive		= false;
 	cp.service_id		= srx->srx_service;
 	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, gfp);
+	if (!IS_ERR(call))
+		call->notify_rx = notify_rx;
 
 	release_sock(&rx->sk);
 	_leave(" = %p", call);
@@ -278,40 +293,39 @@ EXPORT_SYMBOL(rxrpc_kernel_begin_call);
 
 /**
  * rxrpc_kernel_end_call - Allow a kernel service to end a call it was using
+ * @sock: The socket the call is on
  * @call: The call to end
  *
  * Allow a kernel service to end a call it was using.  The call must be
  * complete before this is called (the call should be aborted if necessary).
  */
-void rxrpc_kernel_end_call(struct rxrpc_call *call)
+void rxrpc_kernel_end_call(struct socket *sock, struct rxrpc_call *call)
 {
 	_enter("%d{%d}", call->debug_id, atomic_read(&call->usage));
-	rxrpc_remove_user_ID(call->socket, call);
-	rxrpc_put_call(call);
+	rxrpc_release_call(rxrpc_sk(sock->sk), call);
+	rxrpc_put_call(call, rxrpc_call_put_kernel);
 }
 EXPORT_SYMBOL(rxrpc_kernel_end_call);
 
 /**
- * rxrpc_kernel_intercept_rx_messages - Intercept received RxRPC messages
+ * rxrpc_kernel_new_call_notification - Get notifications of new calls
  * @sock: The socket to intercept received messages on
- * @interceptor: The function to pass the messages to
+ * @notify_new_call: Function to be called when new calls appear
+ * @discard_new_call: Function to discard preallocated calls
  *
- * Allow a kernel service to intercept messages heading for the Rx queue on an
- * RxRPC socket.  They get passed to the specified function instead.
- * @interceptor should free the socket buffers it is given.  @interceptor is
- * called with the socket receive queue spinlock held and softirqs disabled -
- * this ensures that the messages will be delivered in the right order.
+ * Allow a kernel service to be given notifications about new calls.
  */
-void rxrpc_kernel_intercept_rx_messages(struct socket *sock,
-					rxrpc_interceptor_t interceptor)
+void rxrpc_kernel_new_call_notification(
+	struct socket *sock,
+	rxrpc_notify_new_call_t notify_new_call,
+	rxrpc_discard_new_call_t discard_new_call)
 {
 	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 
-	_enter("");
-	rx->interceptor = interceptor;
+	rx->notify_new_call = notify_new_call;
+	rx->discard_new_call = discard_new_call;
 }
-
-EXPORT_SYMBOL(rxrpc_kernel_intercept_rx_messages);
+EXPORT_SYMBOL(rxrpc_kernel_new_call_notification);
 
 /*
  * connect an RxRPC socket
@@ -391,6 +405,23 @@ static int rxrpc_sendmsg(struct socket *sock, struct msghdr *m, size_t len)
 
 	switch (rx->sk.sk_state) {
 	case RXRPC_UNBOUND:
+		rx->srx.srx_family = AF_RXRPC;
+		rx->srx.srx_service = 0;
+		rx->srx.transport_type = SOCK_DGRAM;
+		rx->srx.transport.family = rx->family;
+		switch (rx->family) {
+		case AF_INET:
+			rx->srx.transport_len = sizeof(struct sockaddr_in);
+			break;
+#ifdef CONFIG_AF_RXRPC_IPV6
+		case AF_INET6:
+			rx->srx.transport_len = sizeof(struct sockaddr_in6);
+			break;
+#endif
+		default:
+			ret = -EAFNOSUPPORT;
+			goto error_unlock;
+		}
 		local = rxrpc_lookup_local(&rx->srx);
 		if (IS_ERR(local)) {
 			ret = PTR_ERR(local);
@@ -505,15 +536,16 @@ error:
 static unsigned int rxrpc_poll(struct file *file, struct socket *sock,
 			       poll_table *wait)
 {
-	unsigned int mask;
 	struct sock *sk = sock->sk;
+	struct rxrpc_sock *rx = rxrpc_sk(sk);
+	unsigned int mask;
 
 	sock_poll_wait(file, sk_sleep(sk), wait);
 	mask = 0;
 
 	/* the socket is readable if there are any messages waiting on the Rx
 	 * queue */
-	if (!skb_queue_empty(&sk->sk_receive_queue))
+	if (!list_empty(&rx->recvmsg_q))
 		mask |= POLLIN | POLLRDNORM;
 
 	/* the socket is writable if there is space to add new data to the
@@ -540,7 +572,8 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 		return -EAFNOSUPPORT;
 
 	/* we support transport protocol UDP/UDP6 only */
-	if (protocol != PF_INET)
+	if (protocol != PF_INET &&
+	    IS_ENABLED(CONFIG_AF_RXRPC_IPV6) && protocol != PF_INET6)
 		return -EPROTONOSUPPORT;
 
 	if (sock->type != SOCK_DGRAM)
@@ -554,6 +587,7 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 		return -ENOMEM;
 
 	sock_init_data(sock, sk);
+	sock_set_flag(sk, SOCK_RCU_FREE);
 	sk->sk_state		= RXRPC_UNBOUND;
 	sk->sk_write_space	= rxrpc_write_space;
 	sk->sk_max_ack_backlog	= 0;
@@ -563,9 +597,11 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 	rx->family = protocol;
 	rx->calls = RB_ROOT;
 
-	INIT_LIST_HEAD(&rx->listen_link);
-	INIT_LIST_HEAD(&rx->secureq);
-	INIT_LIST_HEAD(&rx->acceptq);
+	spin_lock_init(&rx->incoming_lock);
+	INIT_LIST_HEAD(&rx->sock_calls);
+	INIT_LIST_HEAD(&rx->to_be_accepted);
+	INIT_LIST_HEAD(&rx->recvmsg_q);
+	rwlock_init(&rx->recvmsg_lock);
 	rwlock_init(&rx->call_lock);
 	memset(&rx->srx, 0, sizeof(rx->srx));
 
@@ -574,6 +610,39 @@ static int rxrpc_create(struct net *net, struct socket *sock, int protocol,
 }
 
 /*
+ * Kill all the calls on a socket and shut it down.
+ */
+static int rxrpc_shutdown(struct socket *sock, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct rxrpc_sock *rx = rxrpc_sk(sk);
+	int ret = 0;
+
+	_enter("%p,%d", sk, flags);
+
+	if (flags != SHUT_RDWR)
+		return -EOPNOTSUPP;
+	if (sk->sk_state == RXRPC_CLOSE)
+		return -ESHUTDOWN;
+
+	lock_sock(sk);
+
+	spin_lock_bh(&sk->sk_receive_queue.lock);
+	if (sk->sk_state < RXRPC_CLOSE) {
+		sk->sk_state = RXRPC_CLOSE;
+		sk->sk_shutdown = SHUTDOWN_MASK;
+	} else {
+		ret = -ESHUTDOWN;
+	}
+	spin_unlock_bh(&sk->sk_receive_queue.lock);
+
+	rxrpc_discard_prealloc(rx);
+
+	release_sock(sk);
+	return ret;
+}
+
+/*
  * RxRPC socket destructor
  */
 static void rxrpc_sock_destructor(struct sock *sk)
@@ -609,15 +678,14 @@ static int rxrpc_release_sock(struct sock *sk)
 	sk->sk_state = RXRPC_CLOSE;
 	spin_unlock_bh(&sk->sk_receive_queue.lock);
 
-	ASSERTCMP(rx->listen_link.next, !=, LIST_POISON1);
-
-	if (!list_empty(&rx->listen_link)) {
-		write_lock_bh(&rx->local->services_lock);
-		list_del(&rx->listen_link);
-		write_unlock_bh(&rx->local->services_lock);
+	if (rx->local && rx->local->service == rx) {
+		write_lock(&rx->local->services_lock);
+		rx->local->service = NULL;
+		write_unlock(&rx->local->services_lock);
 	}
 
 	/* try to flush out this socket */
+	rxrpc_discard_prealloc(rx);
 	rxrpc_release_calls_on_socket(rx);
 	flush_workqueue(rxrpc_workqueue);
 	rxrpc_purge_queue(&sk->sk_receive_queue);
@@ -666,7 +734,7 @@ static const struct proto_ops rxrpc_rpc_ops = {
 	.poll		= rxrpc_poll,
 	.ioctl		= sock_no_ioctl,
 	.listen		= rxrpc_listen,
-	.shutdown	= sock_no_shutdown,
+	.shutdown	= rxrpc_shutdown,
 	.setsockopt	= rxrpc_setsockopt,
 	.getsockopt	= sock_no_getsockopt,
 	.sendmsg	= rxrpc_sendmsg,
@@ -697,7 +765,13 @@ static int __init af_rxrpc_init(void)
 
 	BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > FIELD_SIZEOF(struct sk_buff, cb));
 
-	rxrpc_epoch = get_seconds();
+	get_random_bytes(&rxrpc_epoch, sizeof(rxrpc_epoch));
+	rxrpc_epoch |= RXRPC_RANDOM_EPOCH;
+	get_random_bytes(&rxrpc_client_conn_ids.cur,
+			 sizeof(rxrpc_client_conn_ids.cur));
+	rxrpc_client_conn_ids.cur &= 0x3fffffff;
+	if (rxrpc_client_conn_ids.cur == 0)
+		rxrpc_client_conn_ids.cur = 1;
 
 	ret = -ENOMEM;
 	rxrpc_call_jar = kmem_cache_create(
@@ -788,7 +862,8 @@ static void __exit af_rxrpc_exit(void)
 	proto_unregister(&rxrpc_proto);
 	rxrpc_destroy_all_calls();
 	rxrpc_destroy_all_connections();
-	ASSERTCMP(atomic_read(&rxrpc_n_skbs), ==, 0);
+	ASSERTCMP(atomic_read(&rxrpc_n_tx_skbs), ==, 0);
+	ASSERTCMP(atomic_read(&rxrpc_n_rx_skbs), ==, 0);
 	rxrpc_destroy_all_locals();
 
 	remove_proc_entry("rxrpc_conns", init_net.proc_net);
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index ff83fb1ddd47..d38dffd78085 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -35,11 +35,23 @@ struct rxrpc_crypt {
 #define rxrpc_queue_delayed_work(WS,D)	\
 	queue_delayed_work(rxrpc_workqueue, (WS), (D))
 
-#define rxrpc_queue_call(CALL)	rxrpc_queue_work(&(CALL)->processor)
-
 struct rxrpc_connection;
 
 /*
+ * Mark applied to socket buffers.
+ */
+enum rxrpc_skb_mark {
+	RXRPC_SKB_MARK_DATA,		/* data message */
+	RXRPC_SKB_MARK_FINAL_ACK,	/* final ACK received message */
+	RXRPC_SKB_MARK_BUSY,		/* server busy message */
+	RXRPC_SKB_MARK_REMOTE_ABORT,	/* remote abort message */
+	RXRPC_SKB_MARK_LOCAL_ABORT,	/* local abort message */
+	RXRPC_SKB_MARK_NET_ERROR,	/* network error message */
+	RXRPC_SKB_MARK_LOCAL_ERROR,	/* local error message */
+	RXRPC_SKB_MARK_NEW_CALL,	/* local error message */
+};
+
+/*
  * sk_state for RxRPC sockets
  */
 enum {
@@ -52,19 +64,44 @@ enum {
 };
 
 /*
+ * Service backlog preallocation.
+ *
+ * This contains circular buffers of preallocated peers, connections and calls
+ * for incoming service calls and their head and tail pointers.  This allows
+ * calls to be set up in the data_ready handler, thereby avoiding the need to
+ * shuffle packets around so much.
+ */
+struct rxrpc_backlog {
+	unsigned short		peer_backlog_head;
+	unsigned short		peer_backlog_tail;
+	unsigned short		conn_backlog_head;
+	unsigned short		conn_backlog_tail;
+	unsigned short		call_backlog_head;
+	unsigned short		call_backlog_tail;
+#define RXRPC_BACKLOG_MAX	32
+	struct rxrpc_peer	*peer_backlog[RXRPC_BACKLOG_MAX];
+	struct rxrpc_connection	*conn_backlog[RXRPC_BACKLOG_MAX];
+	struct rxrpc_call	*call_backlog[RXRPC_BACKLOG_MAX];
+};
+
+/*
  * RxRPC socket definition
  */
 struct rxrpc_sock {
 	/* WARNING: sk has to be the first member */
 	struct sock		sk;
-	rxrpc_interceptor_t	interceptor;	/* kernel service Rx interceptor function */
+	rxrpc_notify_new_call_t	notify_new_call; /* Func to notify of new call */
+	rxrpc_discard_new_call_t discard_new_call; /* Func to discard a new call */
 	struct rxrpc_local	*local;		/* local endpoint */
-	struct list_head	listen_link;	/* link in the local endpoint's listen list */
-	struct list_head	secureq;	/* calls awaiting connection security clearance */
-	struct list_head	acceptq;	/* calls awaiting acceptance */
+	struct rxrpc_backlog	*backlog;	/* Preallocation for services */
+	spinlock_t		incoming_lock;	/* Incoming call vs service shutdown lock */
+	struct list_head	sock_calls;	/* List of calls owned by this socket */
+	struct list_head	to_be_accepted;	/* calls awaiting acceptance */
+	struct list_head	recvmsg_q;	/* Calls awaiting recvmsg's attention  */
+	rwlock_t		recvmsg_lock;	/* Lock for recvmsg_q */
 	struct key		*key;		/* security for this socket */
 	struct key		*securities;	/* list of server security descriptors */
-	struct rb_root		calls;		/* outstanding calls on this socket */
+	struct rb_root		calls;		/* User ID -> call mapping */
 	unsigned long		flags;
 #define RXRPC_SOCK_CONNECTED		0	/* connect_srx is set */
 	rwlock_t		call_lock;	/* lock for calls */
@@ -103,13 +140,11 @@ struct rxrpc_host_header {
  * - max 48 bytes (struct sk_buff::cb)
  */
 struct rxrpc_skb_priv {
-	struct rxrpc_call	*call;		/* call with which associated */
-	unsigned long		resend_at;	/* time in jiffies at which to resend */
 	union {
-		unsigned int	offset;		/* offset into buffer of next read */
+		u8		nr_jumbo;	/* Number of jumbo subpackets */
+	};
+	union {
 		int		remain;		/* amount of space remaining for next write */
-		u32		error;		/* network error code */
-		bool		need_resend;	/* T if needs resending */
 	};
 
 	struct rxrpc_host_header hdr;		/* RxRPC packet header from this packet */
@@ -117,13 +152,6 @@ struct rxrpc_skb_priv {
 
 #define rxrpc_skb(__skb) ((struct rxrpc_skb_priv *) &(__skb)->cb)
 
-enum rxrpc_command {
-	RXRPC_CMD_SEND_DATA,		/* send data message */
-	RXRPC_CMD_SEND_ABORT,		/* request abort generation */
-	RXRPC_CMD_ACCEPT,		/* [server] accept incoming call */
-	RXRPC_CMD_REJECT_BUSY,		/* [server] reject a call as busy */
-};
-
 /*
  * RxRPC security module interface
  */
@@ -150,7 +178,12 @@ struct rxrpc_security {
 			     void *);
 
 	/* verify the security on a received packet */
-	int (*verify_packet)(struct rxrpc_call *, struct sk_buff *, u32 *);
+	int (*verify_packet)(struct rxrpc_call *, struct sk_buff *,
+			     unsigned int, unsigned int, rxrpc_seq_t, u16);
+
+	/* Locate the data in a received packet that has been verified. */
+	void (*locate_data)(struct rxrpc_call *, struct sk_buff *,
+			    unsigned int *, unsigned int *);
 
 	/* issue a challenge */
 	int (*issue_challenge)(struct rxrpc_connection *);
@@ -180,9 +213,8 @@ struct rxrpc_local {
 	struct list_head	link;
 	struct socket		*socket;	/* my UDP socket */
 	struct work_struct	processor;
-	struct list_head	services;	/* services listening on this endpoint */
+	struct rxrpc_sock __rcu	*service;	/* Service(s) listening on this endpoint */
 	struct rw_semaphore	defrag_sem;	/* control re-enablement of IP DF bit */
-	struct sk_buff_head	accept_queue;	/* incoming calls awaiting acceptance */
 	struct sk_buff_head	reject_queue;	/* packets awaiting rejection */
 	struct sk_buff_head	event_queue;	/* endpoint event packets awaiting processing */
 	struct rb_root		client_conns;	/* Client connections by socket params */
@@ -220,10 +252,12 @@ struct rxrpc_peer {
 
 	/* calculated RTT cache */
 #define RXRPC_RTT_CACHE_SIZE 32
-	suseconds_t		rtt;		/* current RTT estimate (in uS) */
-	unsigned int		rtt_point;	/* next entry at which to insert */
-	unsigned int		rtt_usage;	/* amount of cache actually used */
-	suseconds_t		rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* calculated RTT cache */
+	ktime_t			rtt_last_req;	/* Time of last RTT request */
+	u64			rtt;		/* Current RTT estimate (in nS) */
+	u64			rtt_sum;	/* Sum of cache contents */
+	u64			rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* Determined RTT cache */
+	u8			rtt_cursor;	/* next entry at which to insert */
+	u8			rtt_usage;	/* amount of cache actually used */
 };
 
 /*
@@ -255,6 +289,9 @@ enum rxrpc_conn_flag {
 	RXRPC_CONN_HAS_IDR,		/* Has a client conn ID assigned */
 	RXRPC_CONN_IN_SERVICE_CONNS,	/* Conn is in peer->service_conns */
 	RXRPC_CONN_IN_CLIENT_CONNS,	/* Conn is in local->client_conns */
+	RXRPC_CONN_EXPOSED,		/* Conn has extra ref for exposure */
+	RXRPC_CONN_DONT_REUSE,		/* Don't reuse this connection */
+	RXRPC_CONN_COUNTED,		/* Counted by rxrpc_nr_client_conns */
 };
 
 /*
@@ -265,17 +302,29 @@ enum rxrpc_conn_event {
 };
 
 /*
+ * The connection cache state.
+ */
+enum rxrpc_conn_cache_state {
+	RXRPC_CONN_CLIENT_INACTIVE,	/* Conn is not yet listed */
+	RXRPC_CONN_CLIENT_WAITING,	/* Conn is on wait list, waiting for capacity */
+	RXRPC_CONN_CLIENT_ACTIVE,	/* Conn is on active list, doing calls */
+	RXRPC_CONN_CLIENT_CULLED,	/* Conn is culled and delisted, doing calls */
+	RXRPC_CONN_CLIENT_IDLE,		/* Conn is on idle list, doing mostly nothing */
+	RXRPC_CONN__NR_CACHE_STATES
+};
+
+/*
  * The connection protocol state.
  */
 enum rxrpc_conn_proto_state {
 	RXRPC_CONN_UNUSED,		/* Connection not yet attempted */
 	RXRPC_CONN_CLIENT,		/* Client connection */
+	RXRPC_CONN_SERVICE_PREALLOC,	/* Service connection preallocation */
 	RXRPC_CONN_SERVICE_UNSECURED,	/* Service unsecured connection */
 	RXRPC_CONN_SERVICE_CHALLENGING,	/* Service challenging for security */
 	RXRPC_CONN_SERVICE,		/* Service secured connection */
 	RXRPC_CONN_REMOTELY_ABORTED,	/* Conn aborted by peer */
 	RXRPC_CONN_LOCALLY_ABORTED,	/* Conn aborted locally */
-	RXRPC_CONN_NETWORK_ERROR,	/* Conn terminated by network error */
 	RXRPC_CONN__NR_STATES
 };
 
@@ -288,23 +337,33 @@ struct rxrpc_connection {
 	struct rxrpc_conn_proto	proto;
 	struct rxrpc_conn_parameters params;
 
-	spinlock_t		channel_lock;
+	atomic_t		usage;
+	struct rcu_head		rcu;
+	struct list_head	cache_link;
 
+	spinlock_t		channel_lock;
+	unsigned char		active_chans;	/* Mask of active channels */
+#define RXRPC_ACTIVE_CHANS_MASK	((1 << RXRPC_MAXCALLS) - 1)
+	struct list_head	waiting_calls;	/* Calls waiting for channels */
 	struct rxrpc_channel {
 		struct rxrpc_call __rcu	*call;		/* Active call */
 		u32			call_id;	/* ID of current call */
 		u32			call_counter;	/* Call ID counter */
 		u32			last_call;	/* ID of last call */
-		u32			last_result;	/* Result of last call (0/abort) */
+		u8			last_type;	/* Type of last packet */
+		u16			last_service_id;
+		union {
+			u32		last_seq;
+			u32		last_abort;
+		};
 	} channels[RXRPC_MAXCALLS];
-	wait_queue_head_t	channel_wq;	/* queue to wait for channel to become available */
 
-	struct rcu_head		rcu;
 	struct work_struct	processor;	/* connection event processor */
 	union {
 		struct rb_node	client_node;	/* Node in local->client_conns */
 		struct rb_node	service_node;	/* Node in peer->service_conns */
 	};
+	struct list_head	proc_link;	/* link in procfs list */
 	struct list_head	link;		/* link in master connection list */
 	struct sk_buff_head	rx_queue;	/* received conn-level packets */
 	const struct rxrpc_security *security;	/* applied security module */
@@ -313,21 +372,18 @@ struct rxrpc_connection {
 	struct rxrpc_crypt	csum_iv;	/* packet checksum base */
 	unsigned long		flags;
 	unsigned long		events;
-	unsigned long		put_time;	/* Time at which last put */
+	unsigned long		idle_timestamp;	/* Time at which last became idle */
 	spinlock_t		state_lock;	/* state-change lock */
-	atomic_t		usage;
-	enum rxrpc_conn_proto_state state : 8;	/* current state of connection */
+	enum rxrpc_conn_cache_state cache_state;
+	enum rxrpc_conn_proto_state state;	/* current state of connection */
 	u32			local_abort;	/* local abort code */
 	u32			remote_abort;	/* remote abort code */
-	int			error;		/* local error incurred */
 	int			debug_id;	/* debug ID for printks */
 	atomic_t		serial;		/* packet serial number counter */
-	atomic_t		hi_serial;	/* highest serial number received */
-	atomic_t		avail_chans;	/* number of channels available */
+	unsigned int		hi_serial;	/* highest serial number received */
+	u32			security_nonce;	/* response re-use preventer */
 	u8			size_align;	/* data size alignment (for security) */
-	u8			header_size;	/* rxrpc + security header size */
 	u8			security_size;	/* security header size */
-	u32			security_nonce;	/* response re-use preventer */
 	u8			security_ix;	/* security type */
 	u8			out_clientflag;	/* RXRPC_CLIENT_INITIATED if we are client */
 };
@@ -337,37 +393,23 @@ struct rxrpc_connection {
  */
 enum rxrpc_call_flag {
 	RXRPC_CALL_RELEASED,		/* call has been released - no more message to userspace */
-	RXRPC_CALL_TERMINAL_MSG,	/* call has given the socket its final message */
-	RXRPC_CALL_RCVD_LAST,		/* all packets received */
-	RXRPC_CALL_RUN_RTIMER,		/* Tx resend timer started */
-	RXRPC_CALL_TX_SOFT_ACK,		/* sent some soft ACKs */
-	RXRPC_CALL_PROC_BUSY,		/* the processor is busy */
-	RXRPC_CALL_INIT_ACCEPT,		/* acceptance was initiated */
 	RXRPC_CALL_HAS_USERID,		/* has a user ID attached */
-	RXRPC_CALL_EXPECT_OOS,		/* expect out of sequence packets */
+	RXRPC_CALL_IS_SERVICE,		/* Call is service call */
+	RXRPC_CALL_EXPOSED,		/* The call was exposed to the world */
+	RXRPC_CALL_RX_LAST,		/* Received the last packet (at rxtx_top) */
+	RXRPC_CALL_TX_LAST,		/* Last packet in Tx buffer (at rxtx_top) */
+	RXRPC_CALL_PINGING,		/* Ping in process */
+	RXRPC_CALL_RETRANS_TIMEOUT,	/* Retransmission due to timeout occurred */
 };
 
 /*
  * Events that can be raised on a call.
  */
 enum rxrpc_call_event {
-	RXRPC_CALL_EV_RCVD_ACKALL,	/* ACKALL or reply received */
-	RXRPC_CALL_EV_RCVD_BUSY,	/* busy packet received */
-	RXRPC_CALL_EV_RCVD_ABORT,	/* abort packet received */
-	RXRPC_CALL_EV_RCVD_ERROR,	/* network error received */
-	RXRPC_CALL_EV_ACK_FINAL,	/* need to generate final ACK (and release call) */
 	RXRPC_CALL_EV_ACK,		/* need to generate ACK */
-	RXRPC_CALL_EV_REJECT_BUSY,	/* need to generate busy message */
 	RXRPC_CALL_EV_ABORT,		/* need to generate abort */
-	RXRPC_CALL_EV_CONN_ABORT,	/* local connection abort generated */
-	RXRPC_CALL_EV_RESEND_TIMER,	/* Tx resend timer expired */
+	RXRPC_CALL_EV_TIMER,		/* Timer expired */
 	RXRPC_CALL_EV_RESEND,		/* Tx resend required */
-	RXRPC_CALL_EV_DRAIN_RX_OOS,	/* drain the Rx out of sequence queue */
-	RXRPC_CALL_EV_LIFE_TIMER,	/* call's lifetimer ran out */
-	RXRPC_CALL_EV_ACCEPTED,		/* incoming call accepted by userspace app */
-	RXRPC_CALL_EV_SECURED,		/* incoming call's connection is now secure */
-	RXRPC_CALL_EV_POST_ACCEPT,	/* need to post an "accept?" message to the app */
-	RXRPC_CALL_EV_RELEASE,		/* need to release the call's resources */
 };
 
 /*
@@ -379,20 +421,38 @@ enum rxrpc_call_state {
 	RXRPC_CALL_CLIENT_SEND_REQUEST,	/* - client sending request phase */
 	RXRPC_CALL_CLIENT_AWAIT_REPLY,	/* - client awaiting reply */
 	RXRPC_CALL_CLIENT_RECV_REPLY,	/* - client receiving reply phase */
-	RXRPC_CALL_CLIENT_FINAL_ACK,	/* - client sending final ACK phase */
+	RXRPC_CALL_SERVER_PREALLOC,	/* - service preallocation */
 	RXRPC_CALL_SERVER_SECURING,	/* - server securing request connection */
 	RXRPC_CALL_SERVER_ACCEPTING,	/* - server accepting request */
 	RXRPC_CALL_SERVER_RECV_REQUEST,	/* - server receiving request */
 	RXRPC_CALL_SERVER_ACK_REQUEST,	/* - server pending ACK of request */
 	RXRPC_CALL_SERVER_SEND_REPLY,	/* - server sending reply */
 	RXRPC_CALL_SERVER_AWAIT_ACK,	/* - server awaiting final ACK */
-	RXRPC_CALL_COMPLETE,		/* - call completed */
-	RXRPC_CALL_SERVER_BUSY,		/* - call rejected by busy server */
+	RXRPC_CALL_COMPLETE,		/* - call complete */
+	NR__RXRPC_CALL_STATES
+};
+
+/*
+ * Call completion condition (state == RXRPC_CALL_COMPLETE).
+ */
+enum rxrpc_call_completion {
+	RXRPC_CALL_SUCCEEDED,		/* - Normal termination */
 	RXRPC_CALL_REMOTELY_ABORTED,	/* - call aborted by peer */
 	RXRPC_CALL_LOCALLY_ABORTED,	/* - call aborted locally on error or close */
+	RXRPC_CALL_LOCAL_ERROR,		/* - call failed due to local error */
 	RXRPC_CALL_NETWORK_ERROR,	/* - call terminated by network error */
-	RXRPC_CALL_DEAD,		/* - call is dead */
-	NR__RXRPC_CALL_STATES
+	NR__RXRPC_CALL_COMPLETIONS
+};
+
+/*
+ * Call Tx congestion management modes.
+ */
+enum rxrpc_congest_mode {
+	RXRPC_CALL_SLOW_START,
+	RXRPC_CALL_CONGEST_AVOIDANCE,
+	RXRPC_CALL_PACKET_LOSS,
+	RXRPC_CALL_FAST_RETRANSMIT,
+	NR__RXRPC_CONGEST_MODES
 };
 
 /*
@@ -402,92 +462,329 @@ enum rxrpc_call_state {
 struct rxrpc_call {
 	struct rcu_head		rcu;
 	struct rxrpc_connection	*conn;		/* connection carrying call */
-	struct rxrpc_sock	*socket;	/* socket responsible */
-	struct timer_list	lifetimer;	/* lifetime remaining on call */
-	struct timer_list	deadspan;	/* reap timer for re-ACK'ing, etc  */
-	struct timer_list	ack_timer;	/* ACK generation timer */
-	struct timer_list	resend_timer;	/* Tx resend timer */
-	struct work_struct	destroyer;	/* call destroyer */
-	struct work_struct	processor;	/* packet processor and ACK generator */
+	struct rxrpc_peer	*peer;		/* Peer record for remote address */
+	struct rxrpc_sock __rcu	*socket;	/* socket responsible */
+	ktime_t			ack_at;		/* When deferred ACK needs to happen */
+	ktime_t			resend_at;	/* When next resend needs to happen */
+	ktime_t			expire_at;	/* When the call times out */
+	struct timer_list	timer;		/* Combined event timer */
+	struct work_struct	processor;	/* Event processor */
+	rxrpc_notify_rx_t	notify_rx;	/* kernel service Rx notification function */
 	struct list_head	link;		/* link in master call list */
+	struct list_head	chan_wait_link;	/* Link in conn->waiting_calls */
 	struct hlist_node	error_link;	/* link in error distribution list */
-	struct list_head	accept_link;	/* calls awaiting acceptance */
-	struct rb_node		sock_node;	/* node in socket call tree */
-	struct sk_buff_head	rx_queue;	/* received packets */
-	struct sk_buff_head	rx_oos_queue;	/* packets received out of sequence */
+	struct list_head	accept_link;	/* Link in rx->acceptq */
+	struct list_head	recvmsg_link;	/* Link in rx->recvmsg_q */
+	struct list_head	sock_link;	/* Link in rx->sock_calls */
+	struct rb_node		sock_node;	/* Node in rx->calls */
 	struct sk_buff		*tx_pending;	/* Tx socket buffer being filled */
-	wait_queue_head_t	tx_waitq;	/* wait for Tx window space to become available */
+	wait_queue_head_t	waitq;		/* Wait queue for channel or Tx */
 	__be32			crypto_buf[2];	/* Temporary packet crypto buffer */
 	unsigned long		user_call_ID;	/* user-defined call ID */
-	unsigned long		creation_jif;	/* time of call creation */
 	unsigned long		flags;
 	unsigned long		events;
 	spinlock_t		lock;
 	rwlock_t		state_lock;	/* lock for state transition */
-	atomic_t		usage;
-	atomic_t		skb_count;	/* Outstanding packets on this call */
-	atomic_t		sequence;	/* Tx data packet sequence counter */
-	u32			local_abort;	/* local abort code */
-	u32			remote_abort;	/* remote abort code */
-	int			error_report;	/* Network error (ICMP/local transport) */
+	u32			abort_code;	/* Local/remote abort code */
 	int			error;		/* Local error incurred */
-	enum rxrpc_call_state	state : 8;	/* current state of call */
+	enum rxrpc_call_state	state;		/* current state of call */
+	enum rxrpc_call_completion completion;	/* Call completion condition */
+	atomic_t		usage;
+	u16			service_id;	/* service ID */
+	u8			security_ix;	/* Security type */
+	u32			call_id;	/* call ID on connection  */
+	u32			cid;		/* connection ID plus channel index */
 	int			debug_id;	/* debug ID for printks */
-	u8			channel;	/* connection channel occupied by this call */
-
-	/* transmission-phase ACK management */
-	u8			acks_head;	/* offset into window of first entry */
-	u8			acks_tail;	/* offset into window of last entry */
-	u8			acks_winsz;	/* size of un-ACK'd window */
-	u8			acks_unacked;	/* lowest unacked packet in last ACK received */
-	int			acks_latest;	/* serial number of latest ACK received */
-	rxrpc_seq_t		acks_hard;	/* highest definitively ACK'd msg seq */
-	unsigned long		*acks_window;	/* sent packet window
-						 * - elements are pointers with LSB set if ACK'd
+	unsigned short		rx_pkt_offset;	/* Current recvmsg packet offset */
+	unsigned short		rx_pkt_len;	/* Current recvmsg packet len */
+
+	/* Rx/Tx circular buffer, depending on phase.
+	 *
+	 * In the Rx phase, packets are annotated with 0 or the number of the
+	 * segment of a jumbo packet each buffer refers to.  There can be up to
+	 * 47 segments in a maximum-size UDP packet.
+	 *
+	 * In the Tx phase, packets are annotated with which buffers have been
+	 * acked.
+	 */
+#define RXRPC_RXTX_BUFF_SIZE	64
+#define RXRPC_RXTX_BUFF_MASK	(RXRPC_RXTX_BUFF_SIZE - 1)
+#define RXRPC_INIT_RX_WINDOW_SIZE 32
+	struct sk_buff		**rxtx_buffer;
+	u8			*rxtx_annotations;
+#define RXRPC_TX_ANNO_ACK	0
+#define RXRPC_TX_ANNO_UNACK	1
+#define RXRPC_TX_ANNO_NAK	2
+#define RXRPC_TX_ANNO_RETRANS	3
+#define RXRPC_TX_ANNO_MASK	0x03
+#define RXRPC_TX_ANNO_LAST	0x04
+#define RXRPC_TX_ANNO_RESENT	0x08
+
+#define RXRPC_RX_ANNO_JUMBO	0x3f		/* Jumbo subpacket number + 1 if not zero */
+#define RXRPC_RX_ANNO_JLAST	0x40		/* Set if last element of a jumbo packet */
+#define RXRPC_RX_ANNO_VERIFIED	0x80		/* Set if verified and decrypted */
+	rxrpc_seq_t		tx_hard_ack;	/* Dead slot in buffer; the first transmitted but
+						 * not hard-ACK'd packet follows this.
+						 */
+	rxrpc_seq_t		tx_top;		/* Highest Tx slot allocated. */
+
+	/* TCP-style slow-start congestion control [RFC5681].  Since the SMSS
+	 * is fixed, we keep these numbers in terms of segments (ie. DATA
+	 * packets) rather than bytes.
+	 */
+#define RXRPC_TX_SMSS		RXRPC_JUMBO_DATALEN
+	u8			cong_cwnd;	/* Congestion window size */
+	u8			cong_extra;	/* Extra to send for congestion management */
+	u8			cong_ssthresh;	/* Slow-start threshold */
+	enum rxrpc_congest_mode	cong_mode:8;	/* Congestion management mode */
+	u8			cong_dup_acks;	/* Count of ACKs showing missing packets */
+	u8			cong_cumul_acks; /* Cumulative ACK count */
+	ktime_t			cong_tstamp;	/* Last time cwnd was changed */
+
+	rxrpc_seq_t		rx_hard_ack;	/* Dead slot in buffer; the first received but not
+						 * consumed packet follows this.
 						 */
+	rxrpc_seq_t		rx_top;		/* Highest Rx slot allocated. */
+	rxrpc_seq_t		rx_expect_next;	/* Expected next packet sequence number */
+	u8			rx_winsize;	/* Size of Rx window */
+	u8			tx_winsize;	/* Maximum size of Tx window */
+	bool			tx_phase;	/* T if transmission phase, F if receive phase */
+	u8			nr_jumbo_bad;	/* Number of jumbo dups/exceeds-windows */
 
 	/* receive-phase ACK management */
-	rxrpc_seq_t		rx_data_expect;	/* next data seq ID expected to be received */
-	rxrpc_seq_t		rx_data_post;	/* next data seq ID expected to be posted */
-	rxrpc_seq_t		rx_data_recv;	/* last data seq ID encountered by recvmsg */
-	rxrpc_seq_t		rx_data_eaten;	/* last data seq ID consumed by recvmsg */
-	rxrpc_seq_t		rx_first_oos;	/* first packet in rx_oos_queue (or 0) */
-	rxrpc_seq_t		ackr_win_top;	/* top of ACK window (rx_data_eaten is bottom) */
-	rxrpc_seq_t		ackr_prev_seq;	/* previous sequence number received */
 	u8			ackr_reason;	/* reason to ACK */
+	u16			ackr_skew;	/* skew on packet being ACK'd */
 	rxrpc_serial_t		ackr_serial;	/* serial of packet being ACK'd */
-	atomic_t		ackr_not_idle;	/* number of packets in Rx queue */
-
-	/* received packet records, 1 bit per record */
-#define RXRPC_ACKR_WINDOW_ASZ DIV_ROUND_UP(RXRPC_MAXACKS, BITS_PER_LONG)
-	unsigned long		ackr_window[RXRPC_ACKR_WINDOW_ASZ + 1];
+	rxrpc_seq_t		ackr_prev_seq;	/* previous sequence number received */
+	rxrpc_seq_t		ackr_consumed;	/* Highest packet shown consumed */
+	rxrpc_seq_t		ackr_seen;	/* Highest packet shown seen */
+	rxrpc_serial_t		ackr_ping;	/* Last ping sent */
+	ktime_t			ackr_ping_time;	/* Time last ping sent */
 
-	u8			in_clientflag;	/* Copy of conn->in_clientflag */
-	struct rxrpc_local	*local;		/* Local endpoint. */
-	u32			call_id;	/* call ID on connection  */
-	u32			cid;		/* connection ID plus channel index */
-	u32			epoch;		/* epoch of this connection */
-	u16			service_id;	/* service ID */
+	/* transmission-phase ACK management */
+	ktime_t			acks_latest_ts;	/* Timestamp of latest ACK received */
+	rxrpc_serial_t		acks_latest;	/* serial number of latest ACK received */
+	rxrpc_seq_t		acks_lowest_nak; /* Lowest NACK in the buffer (or ==tx_hard_ack) */
 };
 
 /*
- * locally abort an RxRPC call
+ * Summary of a new ACK and the changes it made to the Tx buffer packet states.
  */
-static inline void rxrpc_abort_call(struct rxrpc_call *call, u32 abort_code)
-{
-	write_lock_bh(&call->state_lock);
-	if (call->state < RXRPC_CALL_COMPLETE) {
-		call->local_abort = abort_code;
-		call->state = RXRPC_CALL_LOCALLY_ABORTED;
-		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-	}
-	write_unlock_bh(&call->state_lock);
-}
+struct rxrpc_ack_summary {
+	u8			ack_reason;
+	u8			nr_acks;		/* Number of ACKs in packet */
+	u8			nr_nacks;		/* Number of NACKs in packet */
+	u8			nr_new_acks;		/* Number of new ACKs in packet */
+	u8			nr_new_nacks;		/* Number of new NACKs in packet */
+	u8			nr_rot_new_acks;	/* Number of rotated new ACKs */
+	bool			new_low_nack;		/* T if new low NACK found */
+	bool			retrans_timeo;		/* T if reTx due to timeout happened */
+	u8			flight_size;		/* Number of unreceived transmissions */
+	/* Place to stash values for tracing */
+	enum rxrpc_congest_mode	mode:8;
+	u8			cwnd;
+	u8			ssthresh;
+	u8			dup_acks;
+	u8			cumulative_acks;
+};
+
+enum rxrpc_skb_trace {
+	rxrpc_skb_rx_cleaned,
+	rxrpc_skb_rx_freed,
+	rxrpc_skb_rx_got,
+	rxrpc_skb_rx_lost,
+	rxrpc_skb_rx_received,
+	rxrpc_skb_rx_rotated,
+	rxrpc_skb_rx_purged,
+	rxrpc_skb_rx_seen,
+	rxrpc_skb_tx_cleaned,
+	rxrpc_skb_tx_freed,
+	rxrpc_skb_tx_got,
+	rxrpc_skb_tx_new,
+	rxrpc_skb_tx_rotated,
+	rxrpc_skb_tx_seen,
+	rxrpc_skb__nr_trace
+};
+
+extern const char rxrpc_skb_traces[rxrpc_skb__nr_trace][7];
+
+enum rxrpc_conn_trace {
+	rxrpc_conn_new_client,
+	rxrpc_conn_new_service,
+	rxrpc_conn_queued,
+	rxrpc_conn_seen,
+	rxrpc_conn_got,
+	rxrpc_conn_put_client,
+	rxrpc_conn_put_service,
+	rxrpc_conn__nr_trace
+};
+
+extern const char rxrpc_conn_traces[rxrpc_conn__nr_trace][4];
+
+enum rxrpc_client_trace {
+	rxrpc_client_activate_chans,
+	rxrpc_client_alloc,
+	rxrpc_client_chan_activate,
+	rxrpc_client_chan_disconnect,
+	rxrpc_client_chan_pass,
+	rxrpc_client_chan_unstarted,
+	rxrpc_client_cleanup,
+	rxrpc_client_count,
+	rxrpc_client_discard,
+	rxrpc_client_duplicate,
+	rxrpc_client_exposed,
+	rxrpc_client_replace,
+	rxrpc_client_to_active,
+	rxrpc_client_to_culled,
+	rxrpc_client_to_idle,
+	rxrpc_client_to_inactive,
+	rxrpc_client_to_waiting,
+	rxrpc_client_uncount,
+	rxrpc_client__nr_trace
+};
+
+extern const char rxrpc_client_traces[rxrpc_client__nr_trace][7];
+extern const char rxrpc_conn_cache_states[RXRPC_CONN__NR_CACHE_STATES][5];
+
+enum rxrpc_call_trace {
+	rxrpc_call_new_client,
+	rxrpc_call_new_service,
+	rxrpc_call_queued,
+	rxrpc_call_queued_ref,
+	rxrpc_call_seen,
+	rxrpc_call_connected,
+	rxrpc_call_release,
+	rxrpc_call_got,
+	rxrpc_call_got_userid,
+	rxrpc_call_got_kernel,
+	rxrpc_call_put,
+	rxrpc_call_put_userid,
+	rxrpc_call_put_kernel,
+	rxrpc_call_put_noqueue,
+	rxrpc_call_error,
+	rxrpc_call__nr_trace
+};
+
+extern const char rxrpc_call_traces[rxrpc_call__nr_trace][4];
+
+enum rxrpc_transmit_trace {
+	rxrpc_transmit_wait,
+	rxrpc_transmit_queue,
+	rxrpc_transmit_queue_last,
+	rxrpc_transmit_rotate,
+	rxrpc_transmit_rotate_last,
+	rxrpc_transmit_await_reply,
+	rxrpc_transmit_end,
+	rxrpc_transmit__nr_trace
+};
+
+extern const char rxrpc_transmit_traces[rxrpc_transmit__nr_trace][4];
+
+enum rxrpc_receive_trace {
+	rxrpc_receive_incoming,
+	rxrpc_receive_queue,
+	rxrpc_receive_queue_last,
+	rxrpc_receive_front,
+	rxrpc_receive_rotate,
+	rxrpc_receive_end,
+	rxrpc_receive__nr_trace
+};
+
+extern const char rxrpc_receive_traces[rxrpc_receive__nr_trace][4];
+
+enum rxrpc_recvmsg_trace {
+	rxrpc_recvmsg_enter,
+	rxrpc_recvmsg_wait,
+	rxrpc_recvmsg_dequeue,
+	rxrpc_recvmsg_hole,
+	rxrpc_recvmsg_next,
+	rxrpc_recvmsg_cont,
+	rxrpc_recvmsg_full,
+	rxrpc_recvmsg_data_return,
+	rxrpc_recvmsg_terminal,
+	rxrpc_recvmsg_to_be_accepted,
+	rxrpc_recvmsg_return,
+	rxrpc_recvmsg__nr_trace
+};
+
+extern const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5];
+
+enum rxrpc_rtt_tx_trace {
+	rxrpc_rtt_tx_ping,
+	rxrpc_rtt_tx_data,
+	rxrpc_rtt_tx__nr_trace
+};
+
+extern const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5];
+
+enum rxrpc_rtt_rx_trace {
+	rxrpc_rtt_rx_ping_response,
+	rxrpc_rtt_rx_requested_ack,
+	rxrpc_rtt_rx__nr_trace
+};
+
+extern const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5];
+
+enum rxrpc_timer_trace {
+	rxrpc_timer_begin,
+	rxrpc_timer_init_for_reply,
+	rxrpc_timer_expired,
+	rxrpc_timer_set_for_ack,
+	rxrpc_timer_set_for_resend,
+	rxrpc_timer_set_for_send,
+	rxrpc_timer__nr_trace
+};
+
+extern const char rxrpc_timer_traces[rxrpc_timer__nr_trace][8];
+
+enum rxrpc_propose_ack_trace {
+	rxrpc_propose_ack_client_tx_end,
+	rxrpc_propose_ack_input_data,
+	rxrpc_propose_ack_ping_for_lost_ack,
+	rxrpc_propose_ack_ping_for_lost_reply,
+	rxrpc_propose_ack_ping_for_params,
+	rxrpc_propose_ack_respond_to_ack,
+	rxrpc_propose_ack_respond_to_ping,
+	rxrpc_propose_ack_retry_tx,
+	rxrpc_propose_ack_rotate_rx,
+	rxrpc_propose_ack_terminal_ack,
+	rxrpc_propose_ack__nr_trace
+};
+
+enum rxrpc_propose_ack_outcome {
+	rxrpc_propose_ack_use,
+	rxrpc_propose_ack_update,
+	rxrpc_propose_ack_subsume,
+	rxrpc_propose_ack__nr_outcomes
+};
+
+extern const char rxrpc_propose_ack_traces[rxrpc_propose_ack__nr_trace][8];
+extern const char *const rxrpc_propose_ack_outcomes[rxrpc_propose_ack__nr_outcomes];
+
+enum rxrpc_congest_change {
+	rxrpc_cong_begin_retransmission,
+	rxrpc_cong_cleared_nacks,
+	rxrpc_cong_new_low_nack,
+	rxrpc_cong_no_change,
+	rxrpc_cong_progress,
+	rxrpc_cong_retransmit_again,
+	rxrpc_cong_rtt_window_end,
+	rxrpc_cong_saw_nack,
+	rxrpc_congest__nr_change
+};
+
+extern const char rxrpc_congest_modes[NR__RXRPC_CONGEST_MODES][10];
+extern const char rxrpc_congest_changes[rxrpc_congest__nr_change][9];
+
+extern const char *const rxrpc_pkts[];
+extern const char const rxrpc_ack_names[RXRPC_ACK__INVALID + 1][4];
+
+#include <trace/events/rxrpc.h>
 
 /*
  * af_rxrpc.c
  */
-extern atomic_t rxrpc_n_skbs;
+extern atomic_t rxrpc_n_tx_skbs, rxrpc_n_rx_skbs;
 extern u32 rxrpc_epoch;
 extern atomic_t rxrpc_debug_id;
 extern struct workqueue_struct *rxrpc_workqueue;
@@ -495,70 +792,178 @@ extern struct workqueue_struct *rxrpc_workqueue;
 /*
  * call_accept.c
  */
+int rxrpc_service_prealloc(struct rxrpc_sock *, gfp_t);
+void rxrpc_discard_prealloc(struct rxrpc_sock *);
+struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *,
+					   struct rxrpc_connection *,
+					   struct sk_buff *);
 void rxrpc_accept_incoming_calls(struct rxrpc_local *);
-struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *, unsigned long);
+struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *, unsigned long,
+				     rxrpc_notify_rx_t);
 int rxrpc_reject_call(struct rxrpc_sock *);
 
 /*
  * call_event.c
  */
-void __rxrpc_propose_ACK(struct rxrpc_call *, u8, u32, bool);
-void rxrpc_propose_ACK(struct rxrpc_call *, u8, u32, bool);
+void rxrpc_set_timer(struct rxrpc_call *, enum rxrpc_timer_trace, ktime_t);
+void rxrpc_propose_ACK(struct rxrpc_call *, u8, u16, u32, bool, bool,
+		       enum rxrpc_propose_ack_trace);
 void rxrpc_process_call(struct work_struct *);
 
 /*
  * call_object.c
  */
+extern const char *const rxrpc_call_states[];
+extern const char *const rxrpc_call_completions[];
 extern unsigned int rxrpc_max_call_lifetime;
-extern unsigned int rxrpc_dead_call_expiry;
 extern struct kmem_cache *rxrpc_call_jar;
 extern struct list_head rxrpc_calls;
 extern rwlock_t rxrpc_call_lock;
 
 struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *, unsigned long);
+struct rxrpc_call *rxrpc_alloc_call(gfp_t);
 struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *,
 					 struct rxrpc_conn_parameters *,
 					 struct sockaddr_rxrpc *,
 					 unsigned long, gfp_t);
-struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *,
-				       struct rxrpc_connection *,
-				       struct sk_buff *);
-void rxrpc_release_call(struct rxrpc_call *);
+void rxrpc_incoming_call(struct rxrpc_sock *, struct rxrpc_call *,
+			 struct sk_buff *);
+void rxrpc_release_call(struct rxrpc_sock *, struct rxrpc_call *);
 void rxrpc_release_calls_on_socket(struct rxrpc_sock *);
-void __rxrpc_put_call(struct rxrpc_call *);
+bool __rxrpc_queue_call(struct rxrpc_call *);
+bool rxrpc_queue_call(struct rxrpc_call *);
+void rxrpc_see_call(struct rxrpc_call *);
+void rxrpc_get_call(struct rxrpc_call *, enum rxrpc_call_trace);
+void rxrpc_put_call(struct rxrpc_call *, enum rxrpc_call_trace);
+void rxrpc_cleanup_call(struct rxrpc_call *);
 void __exit rxrpc_destroy_all_calls(void);
 
+static inline bool rxrpc_is_service_call(const struct rxrpc_call *call)
+{
+	return test_bit(RXRPC_CALL_IS_SERVICE, &call->flags);
+}
+
+static inline bool rxrpc_is_client_call(const struct rxrpc_call *call)
+{
+	return !rxrpc_is_service_call(call);
+}
+
+/*
+ * Transition a call to the complete state.
+ */
+static inline bool __rxrpc_set_call_completion(struct rxrpc_call *call,
+					       enum rxrpc_call_completion compl,
+					       u32 abort_code,
+					       int error)
+{
+	if (call->state < RXRPC_CALL_COMPLETE) {
+		call->abort_code = abort_code;
+		call->error = error;
+		call->completion = compl,
+		call->state = RXRPC_CALL_COMPLETE;
+		wake_up(&call->waitq);
+		return true;
+	}
+	return false;
+}
+
+static inline bool rxrpc_set_call_completion(struct rxrpc_call *call,
+					     enum rxrpc_call_completion compl,
+					     u32 abort_code,
+					     int error)
+{
+	bool ret;
+
+	write_lock_bh(&call->state_lock);
+	ret = __rxrpc_set_call_completion(call, compl, abort_code, error);
+	write_unlock_bh(&call->state_lock);
+	return ret;
+}
+
+/*
+ * Record that a call successfully completed.
+ */
+static inline bool __rxrpc_call_completed(struct rxrpc_call *call)
+{
+	return __rxrpc_set_call_completion(call, RXRPC_CALL_SUCCEEDED, 0, 0);
+}
+
+static inline bool rxrpc_call_completed(struct rxrpc_call *call)
+{
+	bool ret;
+
+	write_lock_bh(&call->state_lock);
+	ret = __rxrpc_call_completed(call);
+	write_unlock_bh(&call->state_lock);
+	return ret;
+}
+
+/*
+ * Record that a call is locally aborted.
+ */
+static inline bool __rxrpc_abort_call(const char *why, struct rxrpc_call *call,
+				      rxrpc_seq_t seq,
+				      u32 abort_code, int error)
+{
+	trace_rxrpc_abort(why, call->cid, call->call_id, seq,
+			  abort_code, error);
+	return __rxrpc_set_call_completion(call, RXRPC_CALL_LOCALLY_ABORTED,
+					   abort_code, error);
+}
+
+static inline bool rxrpc_abort_call(const char *why, struct rxrpc_call *call,
+				    rxrpc_seq_t seq, u32 abort_code, int error)
+{
+	bool ret;
+
+	write_lock_bh(&call->state_lock);
+	ret = __rxrpc_abort_call(why, call, seq, abort_code, error);
+	write_unlock_bh(&call->state_lock);
+	return ret;
+}
+
 /*
  * conn_client.c
  */
+extern unsigned int rxrpc_max_client_connections;
+extern unsigned int rxrpc_reap_client_connections;
+extern unsigned int rxrpc_conn_idle_client_expiry;
+extern unsigned int rxrpc_conn_idle_client_fast_expiry;
 extern struct idr rxrpc_client_conn_ids;
 
 void rxrpc_destroy_client_conn_ids(void);
 int rxrpc_connect_call(struct rxrpc_call *, struct rxrpc_conn_parameters *,
 		       struct sockaddr_rxrpc *, gfp_t);
-void rxrpc_unpublish_client_conn(struct rxrpc_connection *);
+void rxrpc_expose_client_call(struct rxrpc_call *);
+void rxrpc_disconnect_client_call(struct rxrpc_call *);
+void rxrpc_put_client_conn(struct rxrpc_connection *);
+void __exit rxrpc_destroy_all_client_connections(void);
 
 /*
  * conn_event.c
  */
 void rxrpc_process_connection(struct work_struct *);
-void rxrpc_reject_packet(struct rxrpc_local *, struct sk_buff *);
-void rxrpc_reject_packets(struct rxrpc_local *);
 
 /*
  * conn_object.c
  */
 extern unsigned int rxrpc_connection_expiry;
 extern struct list_head rxrpc_connections;
+extern struct list_head rxrpc_connection_proc_list;
 extern rwlock_t rxrpc_connection_lock;
 
 int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *, struct sk_buff *);
 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t);
 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *,
 						   struct sk_buff *);
-void __rxrpc_disconnect_call(struct rxrpc_call *);
+void __rxrpc_disconnect_call(struct rxrpc_connection *, struct rxrpc_call *);
 void rxrpc_disconnect_call(struct rxrpc_call *);
-void rxrpc_put_connection(struct rxrpc_connection *);
+void rxrpc_kill_connection(struct rxrpc_connection *);
+bool rxrpc_queue_conn(struct rxrpc_connection *);
+void rxrpc_see_connection(struct rxrpc_connection *);
+void rxrpc_get_connection(struct rxrpc_connection *);
+struct rxrpc_connection *rxrpc_get_connection_maybe(struct rxrpc_connection *);
+void rxrpc_put_service_conn(struct rxrpc_connection *);
 void __exit rxrpc_destroy_all_connections(void);
 
 static inline bool rxrpc_conn_is_client(const struct rxrpc_connection *conn)
@@ -571,24 +976,15 @@ static inline bool rxrpc_conn_is_service(const struct rxrpc_connection *conn)
 	return !rxrpc_conn_is_client(conn);
 }
 
-static inline void rxrpc_get_connection(struct rxrpc_connection *conn)
-{
-	atomic_inc(&conn->usage);
-}
-
-static inline
-struct rxrpc_connection *rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
+static inline void rxrpc_put_connection(struct rxrpc_connection *conn)
 {
-	return atomic_inc_not_zero(&conn->usage) ? conn : NULL;
-}
+	if (!conn)
+		return;
 
-static inline bool rxrpc_queue_conn(struct rxrpc_connection *conn)
-{
-	if (!rxrpc_get_connection_maybe(conn))
-		return false;
-	if (!rxrpc_queue_work(&conn->processor))
-		rxrpc_put_connection(conn);
-	return true;
+	if (rxrpc_conn_is_client(conn))
+		rxrpc_put_client_conn(conn);
+	else
+		rxrpc_put_service_conn(conn);
 }
 
 /*
@@ -596,17 +992,14 @@ static inline bool rxrpc_queue_conn(struct rxrpc_connection *conn)
  */
 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
 						     struct sk_buff *);
-struct rxrpc_connection *rxrpc_incoming_connection(struct rxrpc_local *,
-						   struct sockaddr_rxrpc *,
-						   struct sk_buff *);
+struct rxrpc_connection *rxrpc_prealloc_service_connection(gfp_t);
+void rxrpc_new_incoming_connection(struct rxrpc_connection *, struct sk_buff *);
 void rxrpc_unpublish_service_conn(struct rxrpc_connection *);
 
 /*
  * input.c
  */
 void rxrpc_data_ready(struct sock *);
-int rxrpc_queue_rcv_skb(struct rxrpc_call *, struct sk_buff *, bool, bool);
-void rxrpc_fast_process_packet(struct rxrpc_call *, struct sk_buff *);
 
 /*
  * insecure.c
@@ -668,25 +1061,24 @@ extern unsigned int rxrpc_idle_ack_delay;
 extern unsigned int rxrpc_rx_window_size;
 extern unsigned int rxrpc_rx_mtu;
 extern unsigned int rxrpc_rx_jumbo_max;
+extern unsigned int rxrpc_resend_timeout;
 
-extern const char *const rxrpc_pkts[];
 extern const s8 rxrpc_ack_priority[];
 
-extern const char *rxrpc_acks(u8 reason);
-
 /*
  * output.c
  */
-extern unsigned int rxrpc_resend_timeout;
-
-int rxrpc_send_data_packet(struct rxrpc_connection *, struct sk_buff *);
-int rxrpc_do_sendmsg(struct rxrpc_sock *, struct msghdr *, size_t);
+int rxrpc_send_call_packet(struct rxrpc_call *, u8);
+int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *, bool);
+void rxrpc_reject_packets(struct rxrpc_local *);
 
 /*
  * peer_event.c
  */
 void rxrpc_error_report(struct sock *);
 void rxrpc_peer_error_distributor(struct work_struct *);
+void rxrpc_peer_add_rtt(struct rxrpc_call *, enum rxrpc_rtt_rx_trace,
+			rxrpc_serial_t, rxrpc_serial_t, ktime_t, ktime_t);
 
 /*
  * peer_object.c
@@ -696,10 +1088,13 @@ struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *,
 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *,
 				     struct sockaddr_rxrpc *, gfp_t);
 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *, gfp_t);
+struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *,
+					      struct rxrpc_peer *);
 
-static inline void rxrpc_get_peer(struct rxrpc_peer *peer)
+static inline struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
 {
 	atomic_inc(&peer->usage);
+	return peer;
 }
 
 static inline
@@ -718,14 +1113,13 @@ static inline void rxrpc_put_peer(struct rxrpc_peer *peer)
 /*
  * proc.c
  */
-extern const char *const rxrpc_call_states[];
 extern const struct file_operations rxrpc_call_seq_fops;
 extern const struct file_operations rxrpc_connection_seq_fops;
 
 /*
  * recvmsg.c
  */
-void rxrpc_remove_user_ID(struct rxrpc_sock *, struct rxrpc_call *);
+void rxrpc_notify_socket(struct rxrpc_call *);
 int rxrpc_recvmsg(struct socket *, struct msghdr *, size_t, int);
 
 /*
@@ -744,9 +1138,21 @@ int rxrpc_init_client_conn_security(struct rxrpc_connection *);
 int rxrpc_init_server_conn_security(struct rxrpc_connection *);
 
 /*
+ * sendmsg.c
+ */
+int rxrpc_do_sendmsg(struct rxrpc_sock *, struct msghdr *, size_t);
+
+/*
  * skbuff.c
  */
+void rxrpc_kernel_data_consumed(struct rxrpc_call *, struct sk_buff *);
 void rxrpc_packet_destructor(struct sk_buff *);
+void rxrpc_new_skb(struct sk_buff *, enum rxrpc_skb_trace);
+void rxrpc_see_skb(struct sk_buff *, enum rxrpc_skb_trace);
+void rxrpc_get_skb(struct sk_buff *, enum rxrpc_skb_trace);
+void rxrpc_free_skb(struct sk_buff *, enum rxrpc_skb_trace);
+void rxrpc_lose_skb(struct sk_buff *, enum rxrpc_skb_trace);
+void rxrpc_purge_queue(struct sk_buff_head *);
 
 /*
  * sysctl.c
@@ -764,6 +1170,23 @@ static inline void rxrpc_sysctl_exit(void) {}
  */
 int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *, struct sk_buff *);
 
+static inline bool before(u32 seq1, u32 seq2)
+{
+        return (s32)(seq1 - seq2) < 0;
+}
+static inline bool before_eq(u32 seq1, u32 seq2)
+{
+        return (s32)(seq1 - seq2) <= 0;
+}
+static inline bool after(u32 seq1, u32 seq2)
+{
+        return (s32)(seq1 - seq2) > 0;
+}
+static inline bool after_eq(u32 seq1, u32 seq2)
+{
+        return (s32)(seq1 - seq2) >= 0;
+}
+
 /*
  * debug tracing
  */
@@ -846,11 +1269,12 @@ do {								\
 
 #define ASSERTCMP(X, OP, Y)						\
 do {									\
-	unsigned long _x = (unsigned long)(X);				\
-	unsigned long _y = (unsigned long)(Y);				\
+	__typeof__(X) _x = (X);						\
+	__typeof__(Y) _y = (__typeof__(X))(Y);				\
 	if (unlikely(!(_x OP _y))) {					\
-		pr_err("Assertion failed - %lu(0x%lx) %s %lu(0x%lx) is false\n",			\
-		       _x, _x, #OP, _y, _y);				\
+		pr_err("Assertion failed - %lu(0x%lx) %s %lu(0x%lx) is false\n", \
+		       (unsigned long)_x, (unsigned long)_x, #OP,	\
+		       (unsigned long)_y, (unsigned long)_y);		\
 		BUG();							\
 	}								\
 } while (0)
@@ -865,11 +1289,12 @@ do {								\
 
 #define ASSERTIFCMP(C, X, OP, Y)					\
 do {									\
-	unsigned long _x = (unsigned long)(X);				\
-	unsigned long _y = (unsigned long)(Y);				\
+	__typeof__(X) _x = (X);						\
+	__typeof__(Y) _y = (__typeof__(X))(Y);				\
 	if (unlikely((C) && !(_x OP _y))) {				\
 		pr_err("Assertion failed - %lu(0x%lx) %s %lu(0x%lx) is false\n", \
-		       _x, _x, #OP, _y, _y);				\
+		       (unsigned long)_x, (unsigned long)_x, #OP,	\
+		       (unsigned long)_y, (unsigned long)_y);		\
 		BUG();							\
 	}								\
 } while (0)
@@ -893,54 +1318,3 @@ do {						\
 } while (0)
 
 #endif /* __KDEBUGALL */
-
-/*
- * socket buffer accounting / leak finding
- */
-static inline void __rxrpc_new_skb(struct sk_buff *skb, const char *fn)
-{
-	//_net("new skb %p %s [%d]", skb, fn, atomic_read(&rxrpc_n_skbs));
-	//atomic_inc(&rxrpc_n_skbs);
-}
-
-#define rxrpc_new_skb(skb) __rxrpc_new_skb((skb), __func__)
-
-static inline void __rxrpc_kill_skb(struct sk_buff *skb, const char *fn)
-{
-	//_net("kill skb %p %s [%d]", skb, fn, atomic_read(&rxrpc_n_skbs));
-	//atomic_dec(&rxrpc_n_skbs);
-}
-
-#define rxrpc_kill_skb(skb) __rxrpc_kill_skb((skb), __func__)
-
-static inline void __rxrpc_free_skb(struct sk_buff *skb, const char *fn)
-{
-	if (skb) {
-		CHECK_SLAB_OKAY(&skb->users);
-		//_net("free skb %p %s [%d]",
-		//     skb, fn, atomic_read(&rxrpc_n_skbs));
-		//atomic_dec(&rxrpc_n_skbs);
-		kfree_skb(skb);
-	}
-}
-
-#define rxrpc_free_skb(skb) __rxrpc_free_skb((skb), __func__)
-
-static inline void rxrpc_purge_queue(struct sk_buff_head *list)
-{
-	struct sk_buff *skb;
-	while ((skb = skb_dequeue((list))) != NULL)
-		rxrpc_free_skb(skb);
-}
-
-#define rxrpc_get_call(CALL)				\
-do {							\
-	CHECK_SLAB_OKAY(&(CALL)->usage);		\
-	if (atomic_inc_return(&(CALL)->usage) == 1)	\
-		BUG();					\
-} while (0)
-
-#define rxrpc_put_call(CALL)				\
-do {							\
-	__rxrpc_put_call(CALL);				\
-} while (0)
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 9bae21e66d65..3cac231d8405 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -20,265 +20,409 @@
 #include <linux/in6.h>
 #include <linux/icmp.h>
 #include <linux/gfp.h>
+#include <linux/circ_buf.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <net/ip.h>
 #include "ar-internal.h"
 
 /*
- * generate a connection-level abort
+ * Preallocate a single service call, connection and peer and, if possible,
+ * give them a user ID and attach the user's side of the ID to them.
  */
-static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
-		      struct rxrpc_wire_header *whdr)
+static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
+				      struct rxrpc_backlog *b,
+				      rxrpc_notify_rx_t notify_rx,
+				      rxrpc_user_attach_call_t user_attach_call,
+				      unsigned long user_call_ID, gfp_t gfp)
 {
-	struct msghdr msg;
-	struct kvec iov[1];
-	size_t len;
-	int ret;
+	const void *here = __builtin_return_address(0);
+	struct rxrpc_call *call;
+	int max, tmp;
+	unsigned int size = RXRPC_BACKLOG_MAX;
+	unsigned int head, tail, call_head, call_tail;
+
+	max = rx->sk.sk_max_ack_backlog;
+	tmp = rx->sk.sk_ack_backlog;
+	if (tmp >= max) {
+		_leave(" = -ENOBUFS [full %u]", max);
+		return -ENOBUFS;
+	}
+	max -= tmp;
+
+	/* We don't need more conns and peers than we have calls, but on the
+	 * other hand, we shouldn't ever use more peers than conns or conns
+	 * than calls.
+	 */
+	call_head = b->call_backlog_head;
+	call_tail = READ_ONCE(b->call_backlog_tail);
+	tmp = CIRC_CNT(call_head, call_tail, size);
+	if (tmp >= max) {
+		_leave(" = -ENOBUFS [enough %u]", tmp);
+		return -ENOBUFS;
+	}
+	max = tmp + 1;
+
+	head = b->peer_backlog_head;
+	tail = READ_ONCE(b->peer_backlog_tail);
+	if (CIRC_CNT(head, tail, size) < max) {
+		struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp);
+		if (!peer)
+			return -ENOMEM;
+		b->peer_backlog[head] = peer;
+		smp_store_release(&b->peer_backlog_head,
+				  (head + 1) & (size - 1));
+	}
 
-	_enter("%d,,", local->debug_id);
+	head = b->conn_backlog_head;
+	tail = READ_ONCE(b->conn_backlog_tail);
+	if (CIRC_CNT(head, tail, size) < max) {
+		struct rxrpc_connection *conn;
 
-	whdr->type	= RXRPC_PACKET_TYPE_BUSY;
-	whdr->serial	= htonl(1);
+		conn = rxrpc_prealloc_service_connection(gfp);
+		if (!conn)
+			return -ENOMEM;
+		b->conn_backlog[head] = conn;
+		smp_store_release(&b->conn_backlog_head,
+				  (head + 1) & (size - 1));
 
-	msg.msg_name	= &srx->transport.sin;
-	msg.msg_namelen	= sizeof(srx->transport.sin);
-	msg.msg_control	= NULL;
-	msg.msg_controllen = 0;
-	msg.msg_flags	= 0;
+		trace_rxrpc_conn(conn, rxrpc_conn_new_service,
+				 atomic_read(&conn->usage), here);
+	}
 
-	iov[0].iov_base	= whdr;
-	iov[0].iov_len	= sizeof(*whdr);
+	/* Now it gets complicated, because calls get registered with the
+	 * socket here, particularly if a user ID is preassigned by the user.
+	 */
+	call = rxrpc_alloc_call(gfp);
+	if (!call)
+		return -ENOMEM;
+	call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
+	call->state = RXRPC_CALL_SERVER_PREALLOC;
 
-	len = iov[0].iov_len;
+	trace_rxrpc_call(call, rxrpc_call_new_service,
+			 atomic_read(&call->usage),
+			 here, (const void *)user_call_ID);
 
-	_proto("Tx BUSY %%1");
+	write_lock(&rx->call_lock);
+	if (user_attach_call) {
+		struct rxrpc_call *xcall;
+		struct rb_node *parent, **pp;
+
+		/* Check the user ID isn't already in use */
+		pp = &rx->calls.rb_node;
+		parent = NULL;
+		while (*pp) {
+			parent = *pp;
+			xcall = rb_entry(parent, struct rxrpc_call, sock_node);
+			if (user_call_ID < call->user_call_ID)
+				pp = &(*pp)->rb_left;
+			else if (user_call_ID > call->user_call_ID)
+				pp = &(*pp)->rb_right;
+			else
+				goto id_in_use;
+		}
 
-	ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
-	if (ret < 0) {
-		_leave(" = -EAGAIN [sendmsg failed: %d]", ret);
-		return -EAGAIN;
+		call->user_call_ID = user_call_ID;
+		call->notify_rx = notify_rx;
+		rxrpc_get_call(call, rxrpc_call_got_kernel);
+		user_attach_call(call, user_call_ID);
+		rxrpc_get_call(call, rxrpc_call_got_userid);
+		rb_link_node(&call->sock_node, parent, pp);
+		rb_insert_color(&call->sock_node, &rx->calls);
+		set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
 	}
 
-	_leave(" = 0");
+	list_add(&call->sock_link, &rx->sock_calls);
+
+	write_unlock(&rx->call_lock);
+
+	write_lock(&rxrpc_call_lock);
+	list_add_tail(&call->link, &rxrpc_calls);
+	write_unlock(&rxrpc_call_lock);
+
+	b->call_backlog[call_head] = call;
+	smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
+	_leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID);
 	return 0;
+
+id_in_use:
+	write_unlock(&rx->call_lock);
+	rxrpc_cleanup_call(call);
+	_leave(" = -EBADSLT");
+	return -EBADSLT;
 }
 
 /*
- * accept an incoming call that needs peer, transport and/or connection setting
- * up
+ * Preallocate sufficient service connections, calls and peers to cover the
+ * entire backlog of a socket.  When a new call comes in, if we don't have
+ * sufficient of each available, the call gets rejected as busy or ignored.
+ *
+ * The backlog is replenished when a connection is accepted or rejected.
  */
-static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
-				      struct rxrpc_sock *rx,
-				      struct sk_buff *skb,
-				      struct sockaddr_rxrpc *srx)
+int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
 {
-	struct rxrpc_connection *conn;
-	struct rxrpc_skb_priv *sp, *nsp;
-	struct rxrpc_call *call;
-	struct sk_buff *notification;
-	int ret;
+	struct rxrpc_backlog *b = rx->backlog;
 
-	_enter("");
+	if (!b) {
+		b = kzalloc(sizeof(struct rxrpc_backlog), gfp);
+		if (!b)
+			return -ENOMEM;
+		rx->backlog = b;
+	}
+
+	if (rx->discard_new_call)
+		return 0;
+
+	while (rxrpc_service_prealloc_one(rx, b, NULL, NULL, 0, gfp) == 0)
+		;
 
-	sp = rxrpc_skb(skb);
+	return 0;
+}
 
-	/* get a notification message to send to the server app */
-	notification = alloc_skb(0, GFP_NOFS);
-	if (!notification) {
-		_debug("no memory");
-		ret = -ENOMEM;
-		goto error_nofree;
+/*
+ * Discard the preallocation on a service.
+ */
+void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
+{
+	struct rxrpc_backlog *b = rx->backlog;
+	unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
+
+	if (!b)
+		return;
+	rx->backlog = NULL;
+
+	/* Make sure that there aren't any incoming calls in progress before we
+	 * clear the preallocation buffers.
+	 */
+	spin_lock_bh(&rx->incoming_lock);
+	spin_unlock_bh(&rx->incoming_lock);
+
+	head = b->peer_backlog_head;
+	tail = b->peer_backlog_tail;
+	while (CIRC_CNT(head, tail, size) > 0) {
+		struct rxrpc_peer *peer = b->peer_backlog[tail];
+		kfree(peer);
+		tail = (tail + 1) & (size - 1);
 	}
-	rxrpc_new_skb(notification);
-	notification->mark = RXRPC_SKB_MARK_NEW_CALL;
-
-	conn = rxrpc_incoming_connection(local, srx, skb);
-	if (IS_ERR(conn)) {
-		_debug("no conn");
-		ret = PTR_ERR(conn);
-		goto error;
+
+	head = b->conn_backlog_head;
+	tail = b->conn_backlog_tail;
+	while (CIRC_CNT(head, tail, size) > 0) {
+		struct rxrpc_connection *conn = b->conn_backlog[tail];
+		write_lock(&rxrpc_connection_lock);
+		list_del(&conn->link);
+		list_del(&conn->proc_link);
+		write_unlock(&rxrpc_connection_lock);
+		kfree(conn);
+		tail = (tail + 1) & (size - 1);
 	}
 
-	call = rxrpc_incoming_call(rx, conn, skb);
-	rxrpc_put_connection(conn);
-	if (IS_ERR(call)) {
-		_debug("no call");
-		ret = PTR_ERR(call);
-		goto error;
+	head = b->call_backlog_head;
+	tail = b->call_backlog_tail;
+	while (CIRC_CNT(head, tail, size) > 0) {
+		struct rxrpc_call *call = b->call_backlog[tail];
+		if (rx->discard_new_call) {
+			_debug("discard %lx", call->user_call_ID);
+			rx->discard_new_call(call, call->user_call_ID);
+			rxrpc_put_call(call, rxrpc_call_put_kernel);
+		}
+		rxrpc_call_completed(call);
+		rxrpc_release_call(rx, call);
+		rxrpc_put_call(call, rxrpc_call_put);
+		tail = (tail + 1) & (size - 1);
 	}
 
-	/* attach the call to the socket */
-	read_lock_bh(&local->services_lock);
-	if (rx->sk.sk_state == RXRPC_CLOSE)
-		goto invalid_service;
+	kfree(b);
+}
 
-	write_lock(&rx->call_lock);
-	if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
-		rxrpc_get_call(call);
-
-		spin_lock(&call->conn->state_lock);
-		if (sp->hdr.securityIndex > 0 &&
-		    call->conn->state == RXRPC_CONN_SERVICE_UNSECURED) {
-			_debug("await conn sec");
-			list_add_tail(&call->accept_link, &rx->secureq);
-			call->conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
-			set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
-			rxrpc_queue_conn(call->conn);
-		} else {
-			_debug("conn ready");
-			call->state = RXRPC_CALL_SERVER_ACCEPTING;
-			list_add_tail(&call->accept_link, &rx->acceptq);
-			rxrpc_get_call(call);
-			atomic_inc(&call->skb_count);
-			nsp = rxrpc_skb(notification);
-			nsp->call = call;
-
-			ASSERTCMP(atomic_read(&call->usage), >=, 3);
-
-			_debug("notify");
-			spin_lock(&call->lock);
-			ret = rxrpc_queue_rcv_skb(call, notification, true,
-						  false);
-			spin_unlock(&call->lock);
-			notification = NULL;
-			BUG_ON(ret < 0);
+/*
+ * Allocate a new incoming call from the prealloc pool, along with a connection
+ * and a peer as necessary.
+ */
+static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
+						    struct rxrpc_local *local,
+						    struct rxrpc_connection *conn,
+						    struct sk_buff *skb)
+{
+	struct rxrpc_backlog *b = rx->backlog;
+	struct rxrpc_peer *peer, *xpeer;
+	struct rxrpc_call *call;
+	unsigned short call_head, conn_head, peer_head;
+	unsigned short call_tail, conn_tail, peer_tail;
+	unsigned short call_count, conn_count;
+
+	/* #calls >= #conns >= #peers must hold true. */
+	call_head = smp_load_acquire(&b->call_backlog_head);
+	call_tail = b->call_backlog_tail;
+	call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX);
+	conn_head = smp_load_acquire(&b->conn_backlog_head);
+	conn_tail = b->conn_backlog_tail;
+	conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX);
+	ASSERTCMP(conn_count, >=, call_count);
+	peer_head = smp_load_acquire(&b->peer_backlog_head);
+	peer_tail = b->peer_backlog_tail;
+	ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=,
+		  conn_count);
+
+	if (call_count == 0)
+		return NULL;
+
+	if (!conn) {
+		/* No connection.  We're going to need a peer to start off
+		 * with.  If one doesn't yet exist, use a spare from the
+		 * preallocation set.  We dump the address into the spare in
+		 * anticipation - and to save on stack space.
+		 */
+		xpeer = b->peer_backlog[peer_tail];
+		if (rxrpc_extract_addr_from_skb(&xpeer->srx, skb) < 0)
+			return NULL;
+
+		peer = rxrpc_lookup_incoming_peer(local, xpeer);
+		if (peer == xpeer) {
+			b->peer_backlog[peer_tail] = NULL;
+			smp_store_release(&b->peer_backlog_tail,
+					  (peer_tail + 1) &
+					  (RXRPC_BACKLOG_MAX - 1));
 		}
-		spin_unlock(&call->conn->state_lock);
 
-		_debug("queued");
+		/* Now allocate and set up the connection */
+		conn = b->conn_backlog[conn_tail];
+		b->conn_backlog[conn_tail] = NULL;
+		smp_store_release(&b->conn_backlog_tail,
+				  (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
+		rxrpc_get_local(local);
+		conn->params.local = local;
+		conn->params.peer = peer;
+		rxrpc_see_connection(conn);
+		rxrpc_new_incoming_connection(conn, skb);
+	} else {
+		rxrpc_get_connection(conn);
 	}
-	write_unlock(&rx->call_lock);
 
-	_debug("process");
-	rxrpc_fast_process_packet(call, skb);
+	/* And now we can allocate and set up a new call */
+	call = b->call_backlog[call_tail];
+	b->call_backlog[call_tail] = NULL;
+	smp_store_release(&b->call_backlog_tail,
+			  (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
 
-	_debug("done");
-	read_unlock_bh(&local->services_lock);
-	rxrpc_free_skb(notification);
-	rxrpc_put_call(call);
-	_leave(" = 0");
-	return 0;
-
-invalid_service:
-	_debug("invalid");
-	read_unlock_bh(&local->services_lock);
-
-	read_lock_bh(&call->state_lock);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
-		rxrpc_get_call(call);
-		rxrpc_queue_call(call);
-	}
-	read_unlock_bh(&call->state_lock);
-	rxrpc_put_call(call);
-	ret = -ECONNREFUSED;
-error:
-	rxrpc_free_skb(notification);
-error_nofree:
-	_leave(" = %d", ret);
-	return ret;
+	rxrpc_see_call(call);
+	call->conn = conn;
+	call->peer = rxrpc_get_peer(conn->params.peer);
+	return call;
 }
 
 /*
- * accept incoming calls that need peer, transport and/or connection setting up
- * - the packets we get are all incoming client DATA packets that have seq == 1
+ * Set up a new incoming call.  Called in BH context with the RCU read lock
+ * held.
+ *
+ * If this is for a kernel service, when we allocate the call, it will have
+ * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
+ * retainer ref obtained from the backlog buffer.  Prealloc calls for userspace
+ * services only have the ref from the backlog buffer.  We want to pass this
+ * ref to non-BH context to dispose of.
+ *
+ * If we want to report an error, we mark the skb with the packet type and
+ * abort code and return NULL.
  */
-void rxrpc_accept_incoming_calls(struct rxrpc_local *local)
+struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
+					   struct rxrpc_connection *conn,
+					   struct sk_buff *skb)
 {
-	struct rxrpc_skb_priv *sp;
-	struct sockaddr_rxrpc srx;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct rxrpc_sock *rx;
-	struct rxrpc_wire_header whdr;
-	struct sk_buff *skb;
-	int ret;
+	struct rxrpc_call *call;
+	u16 service_id = sp->hdr.serviceId;
 
-	_enter("%d", local->debug_id);
+	_enter("");
 
-	skb = skb_dequeue(&local->accept_queue);
-	if (!skb) {
-		_leave("\n");
-		return;
+	/* Get the socket providing the service */
+	rx = rcu_dereference(local->service);
+	if (service_id == rx->srx.srx_service)
+		goto found_service;
+
+	trace_rxrpc_abort("INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+			  RX_INVALID_OPERATION, EOPNOTSUPP);
+	skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
+	skb->priority = RX_INVALID_OPERATION;
+	_leave(" = NULL [service]");
+	return NULL;
+
+found_service:
+	spin_lock(&rx->incoming_lock);
+	if (rx->sk.sk_state == RXRPC_CLOSE) {
+		trace_rxrpc_abort("CLS", sp->hdr.cid, sp->hdr.callNumber,
+				  sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN);
+		skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
+		skb->priority = RX_INVALID_OPERATION;
+		_leave(" = NULL [close]");
+		call = NULL;
+		goto out;
 	}
 
-	_net("incoming call skb %p", skb);
-
-	sp = rxrpc_skb(skb);
-
-	/* Set up a response packet header in case we need it */
-	whdr.epoch	= htonl(sp->hdr.epoch);
-	whdr.cid	= htonl(sp->hdr.cid);
-	whdr.callNumber	= htonl(sp->hdr.callNumber);
-	whdr.seq	= htonl(sp->hdr.seq);
-	whdr.serial	= 0;
-	whdr.flags	= 0;
-	whdr.type	= 0;
-	whdr.userStatus	= 0;
-	whdr.securityIndex = sp->hdr.securityIndex;
-	whdr._rsvd	= 0;
-	whdr.serviceId	= htons(sp->hdr.serviceId);
-
-	if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
-		goto drop;
-
-	/* get the socket providing the service */
-	read_lock_bh(&local->services_lock);
-	list_for_each_entry(rx, &local->services, listen_link) {
-		if (rx->srx.srx_service == sp->hdr.serviceId &&
-		    rx->sk.sk_state != RXRPC_CLOSE)
-			goto found_service;
+	call = rxrpc_alloc_incoming_call(rx, local, conn, skb);
+	if (!call) {
+		skb->mark = RXRPC_SKB_MARK_BUSY;
+		_leave(" = NULL [busy]");
+		call = NULL;
+		goto out;
 	}
-	read_unlock_bh(&local->services_lock);
-	goto invalid_service;
 
-found_service:
-	_debug("found service %hd", rx->srx.srx_service);
-	if (sk_acceptq_is_full(&rx->sk))
-		goto backlog_full;
-	sk_acceptq_added(&rx->sk);
-	sock_hold(&rx->sk);
-	read_unlock_bh(&local->services_lock);
-
-	ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
-	if (ret < 0)
-		sk_acceptq_removed(&rx->sk);
-	sock_put(&rx->sk);
-	switch (ret) {
-	case -ECONNRESET: /* old calls are ignored */
-	case -ECONNABORTED: /* aborted calls are reaborted or ignored */
-	case 0:
-		return;
-	case -ECONNREFUSED:
-		goto invalid_service;
-	case -EBUSY:
-		goto busy;
-	case -EKEYREJECTED:
-		goto security_mismatch;
+	trace_rxrpc_receive(call, rxrpc_receive_incoming,
+			    sp->hdr.serial, sp->hdr.seq);
+
+	/* Make the call live. */
+	rxrpc_incoming_call(rx, call, skb);
+	conn = call->conn;
+
+	if (rx->notify_new_call)
+		rx->notify_new_call(&rx->sk, call, call->user_call_ID);
+	else
+		sk_acceptq_added(&rx->sk);
+
+	spin_lock(&conn->state_lock);
+	switch (conn->state) {
+	case RXRPC_CONN_SERVICE_UNSECURED:
+		conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
+		set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
+		rxrpc_queue_conn(call->conn);
+		break;
+
+	case RXRPC_CONN_SERVICE:
+		write_lock(&call->state_lock);
+		if (rx->discard_new_call)
+			call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
+		else
+			call->state = RXRPC_CALL_SERVER_ACCEPTING;
+		write_unlock(&call->state_lock);
+		break;
+
+	case RXRPC_CONN_REMOTELY_ABORTED:
+		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
+					  conn->remote_abort, ECONNABORTED);
+		break;
+	case RXRPC_CONN_LOCALLY_ABORTED:
+		rxrpc_abort_call("CON", call, sp->hdr.seq,
+				 conn->local_abort, ECONNABORTED);
+		break;
 	default:
 		BUG();
 	}
+	spin_unlock(&conn->state_lock);
 
-backlog_full:
-	read_unlock_bh(&local->services_lock);
-busy:
-	rxrpc_busy(local, &srx, &whdr);
-	rxrpc_free_skb(skb);
-	return;
+	if (call->state == RXRPC_CALL_SERVER_ACCEPTING)
+		rxrpc_notify_socket(call);
 
-drop:
-	rxrpc_free_skb(skb);
-	return;
+	/* We have to discard the prealloc queue's ref here and rely on a
+	 * combination of the RCU read lock and refs held either by the socket
+	 * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel
+	 * service to prevent the call from being deallocated too early.
+	 */
+	rxrpc_put_call(call, rxrpc_call_put);
 
-invalid_service:
-	skb->priority = RX_INVALID_OPERATION;
-	rxrpc_reject_packet(local, skb);
-	return;
-
-	/* can't change connection security type mid-flow */
-security_mismatch:
-	skb->priority = RX_PROTOCOL_ERROR;
-	rxrpc_reject_packet(local, skb);
-	return;
+	_leave(" = %p{%d}", call, call->debug_id);
+out:
+	spin_unlock(&rx->incoming_lock);
+	return call;
 }
 
 /*
@@ -286,7 +430,8 @@ security_mismatch:
  * - assign the user call ID to the call at the front of the queue
  */
 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
-				     unsigned long user_call_ID)
+				     unsigned long user_call_ID,
+				     rxrpc_notify_rx_t notify_rx)
 {
 	struct rxrpc_call *call;
 	struct rb_node *parent, **pp;
@@ -298,12 +443,13 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 
 	write_lock(&rx->call_lock);
 
-	ret = -ENODATA;
-	if (list_empty(&rx->acceptq))
-		goto out;
+	if (list_empty(&rx->to_be_accepted)) {
+		write_unlock(&rx->call_lock);
+		kleave(" = -ENODATA [empty]");
+		return ERR_PTR(-ENODATA);
+	}
 
 	/* check the user ID isn't already in use */
-	ret = -EBADSLT;
 	pp = &rx->calls.rb_node;
 	parent = NULL;
 	while (*pp) {
@@ -315,62 +461,59 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 		else if (user_call_ID > call->user_call_ID)
 			pp = &(*pp)->rb_right;
 		else
-			goto out;
+			goto id_in_use;
 	}
 
-	/* dequeue the first call and check it's still valid */
-	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
+	/* Dequeue the first call and check it's still valid.  We gain
+	 * responsibility for the queue's reference.
+	 */
+	call = list_entry(rx->to_be_accepted.next,
+			  struct rxrpc_call, accept_link);
 	list_del_init(&call->accept_link);
 	sk_acceptq_removed(&rx->sk);
+	rxrpc_see_call(call);
 
 	write_lock_bh(&call->state_lock);
 	switch (call->state) {
 	case RXRPC_CALL_SERVER_ACCEPTING:
 		call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 		break;
-	case RXRPC_CALL_REMOTELY_ABORTED:
-	case RXRPC_CALL_LOCALLY_ABORTED:
-		ret = -ECONNABORTED;
-		goto out_release;
-	case RXRPC_CALL_NETWORK_ERROR:
-		ret = call->conn->error;
+	case RXRPC_CALL_COMPLETE:
+		ret = call->error;
 		goto out_release;
-	case RXRPC_CALL_DEAD:
-		ret = -ETIME;
-		goto out_discard;
 	default:
 		BUG();
 	}
 
 	/* formalise the acceptance */
+	call->notify_rx = notify_rx;
 	call->user_call_ID = user_call_ID;
+	rxrpc_get_call(call, rxrpc_call_got_userid);
 	rb_link_node(&call->sock_node, parent, pp);
 	rb_insert_color(&call->sock_node, &rx->calls);
 	if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 		BUG();
-	if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
-		BUG();
-	rxrpc_queue_call(call);
 
-	rxrpc_get_call(call);
 	write_unlock_bh(&call->state_lock);
 	write_unlock(&rx->call_lock);
+	rxrpc_notify_socket(call);
+	rxrpc_service_prealloc(rx, GFP_KERNEL);
 	_leave(" = %p{%d}", call, call->debug_id);
 	return call;
 
-	/* if the call is already dying or dead, then we leave the socket's ref
-	 * on it to be released by rxrpc_dead_call_expired() as induced by
-	 * rxrpc_release_call() */
 out_release:
 	_debug("release %p", call);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
-out_discard:
 	write_unlock_bh(&call->state_lock);
-	_debug("discard %p", call);
-out:
 	write_unlock(&rx->call_lock);
+	rxrpc_release_call(rx, call);
+	rxrpc_put_call(call, rxrpc_call_put);
+	goto out;
+
+id_in_use:
+	ret = -EBADSLT;
+	write_unlock(&rx->call_lock);
+out:
+	rxrpc_service_prealloc(rx, GFP_KERNEL);
 	_leave(" = %d", ret);
 	return ERR_PTR(ret);
 }
@@ -382,6 +525,7 @@ out:
 int rxrpc_reject_call(struct rxrpc_sock *rx)
 {
 	struct rxrpc_call *call;
+	bool abort = false;
 	int ret;
 
 	_enter("");
@@ -390,88 +534,73 @@ int rxrpc_reject_call(struct rxrpc_sock *rx)
 
 	write_lock(&rx->call_lock);
 
-	ret = -ENODATA;
-	if (list_empty(&rx->acceptq))
-		goto out;
+	if (list_empty(&rx->to_be_accepted)) {
+		write_unlock(&rx->call_lock);
+		return -ENODATA;
+	}
 
-	/* dequeue the first call and check it's still valid */
-	call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
+	/* Dequeue the first call and check it's still valid.  We gain
+	 * responsibility for the queue's reference.
+	 */
+	call = list_entry(rx->to_be_accepted.next,
+			  struct rxrpc_call, accept_link);
 	list_del_init(&call->accept_link);
 	sk_acceptq_removed(&rx->sk);
+	rxrpc_see_call(call);
 
 	write_lock_bh(&call->state_lock);
 	switch (call->state) {
 	case RXRPC_CALL_SERVER_ACCEPTING:
-		call->state = RXRPC_CALL_SERVER_BUSY;
-		if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
-			rxrpc_queue_call(call);
-		ret = 0;
-		goto out_release;
-	case RXRPC_CALL_REMOTELY_ABORTED:
-	case RXRPC_CALL_LOCALLY_ABORTED:
-		ret = -ECONNABORTED;
-		goto out_release;
-	case RXRPC_CALL_NETWORK_ERROR:
-		ret = call->conn->error;
-		goto out_release;
-	case RXRPC_CALL_DEAD:
-		ret = -ETIME;
+		__rxrpc_abort_call("REJ", call, 1, RX_USER_ABORT, ECONNABORTED);
+		abort = true;
+		/* fall through */
+	case RXRPC_CALL_COMPLETE:
+		ret = call->error;
 		goto out_discard;
 	default:
 		BUG();
 	}
 
-	/* if the call is already dying or dead, then we leave the socket's ref
-	 * on it to be released by rxrpc_dead_call_expired() as induced by
-	 * rxrpc_release_call() */
-out_release:
-	_debug("release %p", call);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
 out_discard:
 	write_unlock_bh(&call->state_lock);
-	_debug("discard %p", call);
-out:
 	write_unlock(&rx->call_lock);
+	if (abort) {
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
+		rxrpc_release_call(rx, call);
+		rxrpc_put_call(call, rxrpc_call_put);
+	}
+	rxrpc_service_prealloc(rx, GFP_KERNEL);
 	_leave(" = %d", ret);
 	return ret;
 }
 
-/**
- * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
- * @sock: The socket on which the impending call is waiting
- * @user_call_ID: The tag to attach to the call
+/*
+ * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
+ * @sock: The socket on which to preallocate
+ * @notify_rx: Event notification function for the call
+ * @user_attach_call: Func to attach call to user_call_ID
+ * @user_call_ID: The tag to attach to the preallocated call
+ * @gfp: The allocation conditions.
  *
- * Allow a kernel service to accept an incoming call, assuming the incoming
- * call is still valid.
- */
-struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
-					    unsigned long user_call_ID)
-{
-	struct rxrpc_call *call;
-
-	_enter(",%lx", user_call_ID);
-	call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
-	_leave(" = %p", call);
-	return call;
-}
-EXPORT_SYMBOL(rxrpc_kernel_accept_call);
-
-/**
- * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
- * @sock: The socket on which the impending call is waiting
+ * Charge up the socket with preallocated calls, each with a user ID.  A
+ * function should be provided to effect the attachment from the user's side.
+ * The user is given a ref to hold on the call.
  *
- * Allow a kernel service to reject an incoming call with a BUSY message,
- * assuming the incoming call is still valid.
+ * Note that the call may be come connected before this function returns.
  */
-int rxrpc_kernel_reject_call(struct socket *sock)
+int rxrpc_kernel_charge_accept(struct socket *sock,
+			       rxrpc_notify_rx_t notify_rx,
+			       rxrpc_user_attach_call_t user_attach_call,
+			       unsigned long user_call_ID, gfp_t gfp)
 {
-	int ret;
+	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
+	struct rxrpc_backlog *b = rx->backlog;
 
-	_enter("");
-	ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
-	_leave(" = %d", ret);
-	return ret;
+	if (sock->sk->sk_state == RXRPC_CLOSE)
+		return -ESHUTDOWN;
+
+	return rxrpc_service_prealloc_one(rx, b, notify_rx,
+					  user_attach_call, user_call_ID,
+					  gfp);
 }
-EXPORT_SYMBOL(rxrpc_kernel_reject_call);
+EXPORT_SYMBOL(rxrpc_kernel_charge_accept);
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index e60cf65c2232..4f00476630b9 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -22,1281 +22,351 @@
 #include "ar-internal.h"
 
 /*
- * propose an ACK be sent
+ * Set the timer
  */
-void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
-			 u32 serial, bool immediate)
+void rxrpc_set_timer(struct rxrpc_call *call, enum rxrpc_timer_trace why,
+		     ktime_t now)
 {
-	unsigned long expiry;
-	s8 prior = rxrpc_ack_priority[ack_reason];
-
-	ASSERTCMP(prior, >, 0);
-
-	_enter("{%d},%s,%%%x,%u",
-	       call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
-
-	if (prior < rxrpc_ack_priority[call->ackr_reason]) {
-		if (immediate)
-			goto cancel_timer;
-		return;
-	}
+	unsigned long t_j, now_j = jiffies;
+	ktime_t t;
+	bool queue = false;
 
-	/* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
-	 * numbers */
-	if (prior == rxrpc_ack_priority[call->ackr_reason]) {
-		if (prior <= 4)
-			call->ackr_serial = serial;
-		if (immediate)
-			goto cancel_timer;
-		return;
-	}
-
-	call->ackr_reason = ack_reason;
-	call->ackr_serial = serial;
-
-	switch (ack_reason) {
-	case RXRPC_ACK_DELAY:
-		_debug("run delay timer");
-		expiry = rxrpc_soft_ack_delay;
-		goto run_timer;
-
-	case RXRPC_ACK_IDLE:
-		if (!immediate) {
-			_debug("run defer timer");
-			expiry = rxrpc_idle_ack_delay;
-			goto run_timer;
-		}
-		goto cancel_timer;
-
-	case RXRPC_ACK_REQUESTED:
-		expiry = rxrpc_requested_ack_delay;
-		if (!expiry)
-			goto cancel_timer;
-		if (!immediate || serial == 1) {
-			_debug("run defer timer");
-			goto run_timer;
-		}
-
-	default:
-		_debug("immediate ACK");
-		goto cancel_timer;
-	}
-
-run_timer:
-	expiry += jiffies;
-	if (!timer_pending(&call->ack_timer) ||
-	    time_after(call->ack_timer.expires, expiry))
-		mod_timer(&call->ack_timer, expiry);
-	return;
-
-cancel_timer:
-	_debug("cancel timer %%%u", serial);
-	try_to_del_timer_sync(&call->ack_timer);
 	read_lock_bh(&call->state_lock);
-	if (call->state <= RXRPC_CALL_COMPLETE &&
-	    !test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events))
-		rxrpc_queue_call(call);
-	read_unlock_bh(&call->state_lock);
-}
-
-/*
- * propose an ACK be sent, locking the call structure
- */
-void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
-		       u32 serial, bool immediate)
-{
-	s8 prior = rxrpc_ack_priority[ack_reason];
-
-	if (prior > rxrpc_ack_priority[call->ackr_reason]) {
-		spin_lock_bh(&call->lock);
-		__rxrpc_propose_ACK(call, ack_reason, serial, immediate);
-		spin_unlock_bh(&call->lock);
-	}
-}
 
-/*
- * set the resend timer
- */
-static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
-			     unsigned long resend_at)
-{
-	read_lock_bh(&call->state_lock);
-	if (call->state >= RXRPC_CALL_COMPLETE)
-		resend = 0;
-
-	if (resend & 1) {
-		_debug("SET RESEND");
-		set_bit(RXRPC_CALL_EV_RESEND, &call->events);
-	}
-
-	if (resend & 2) {
-		_debug("MODIFY RESEND TIMER");
-		set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-		mod_timer(&call->resend_timer, resend_at);
-	} else {
-		_debug("KILL RESEND TIMER");
-		del_timer_sync(&call->resend_timer);
-		clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
-		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-	}
-	read_unlock_bh(&call->state_lock);
-}
-
-/*
- * resend packets
- */
-static void rxrpc_resend(struct rxrpc_call *call)
-{
-	struct rxrpc_wire_header *whdr;
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *txb;
-	unsigned long *p_txb, resend_at;
-	bool stop;
-	int loop;
-	u8 resend;
-
-	_enter("{%d,%d,%d,%d},",
-	       call->acks_hard, call->acks_unacked,
-	       atomic_read(&call->sequence),
-	       CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
-
-	stop = false;
-	resend = 0;
-	resend_at = 0;
-
-	for (loop = call->acks_tail;
-	     loop != call->acks_head || stop;
-	     loop = (loop + 1) &  (call->acks_winsz - 1)
-	     ) {
-		p_txb = call->acks_window + loop;
-		smp_read_barrier_depends();
-		if (*p_txb & 1)
-			continue;
-
-		txb = (struct sk_buff *) *p_txb;
-		sp = rxrpc_skb(txb);
-
-		if (sp->need_resend) {
-			sp->need_resend = false;
-
-			/* each Tx packet has a new serial number */
-			sp->hdr.serial = atomic_inc_return(&call->conn->serial);
-
-			whdr = (struct rxrpc_wire_header *)txb->head;
-			whdr->serial = htonl(sp->hdr.serial);
-
-			_proto("Tx DATA %%%u { #%d }",
-			       sp->hdr.serial, sp->hdr.seq);
-			if (rxrpc_send_data_packet(call->conn, txb) < 0) {
-				stop = true;
-				sp->resend_at = jiffies + 3;
-			} else {
-				sp->resend_at =
-					jiffies + rxrpc_resend_timeout;
-			}
+	if (call->state < RXRPC_CALL_COMPLETE) {
+		t = call->expire_at;
+		if (!ktime_after(t, now))
+			goto out;
+
+		if (!ktime_after(call->resend_at, now)) {
+			call->resend_at = call->expire_at;
+			if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
+				queue = true;
+		} else if (ktime_before(call->resend_at, t)) {
+			t = call->resend_at;
 		}
 
-		if (time_after_eq(jiffies + 1, sp->resend_at)) {
-			sp->need_resend = true;
-			resend |= 1;
-		} else if (resend & 2) {
-			if (time_before(sp->resend_at, resend_at))
-				resend_at = sp->resend_at;
-		} else {
-			resend_at = sp->resend_at;
-			resend |= 2;
+		if (!ktime_after(call->ack_at, now)) {
+			call->ack_at = call->expire_at;
+			if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events))
+				queue = true;
+		} else if (ktime_before(call->ack_at, t)) {
+			t = call->ack_at;
 		}
-	}
-
-	rxrpc_set_resend(call, resend, resend_at);
-	_leave("");
-}
-
-/*
- * handle resend timer expiry
- */
-static void rxrpc_resend_timer(struct rxrpc_call *call)
-{
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *txb;
-	unsigned long *p_txb, resend_at;
-	int loop;
-	u8 resend;
-
-	_enter("%d,%d,%d",
-	       call->acks_tail, call->acks_unacked, call->acks_head);
-
-	if (call->state >= RXRPC_CALL_COMPLETE)
-		return;
-
-	resend = 0;
-	resend_at = 0;
 
-	for (loop = call->acks_unacked;
-	     loop != call->acks_head;
-	     loop = (loop + 1) &  (call->acks_winsz - 1)
-	     ) {
-		p_txb = call->acks_window + loop;
-		smp_read_barrier_depends();
-		txb = (struct sk_buff *) (*p_txb & ~1);
-		sp = rxrpc_skb(txb);
+		t_j = nsecs_to_jiffies(ktime_to_ns(ktime_sub(t, now)));
+		t_j += jiffies;
 
-		ASSERT(!(*p_txb & 1));
+		/* We have to make sure that the calculated jiffies value falls
+		 * at or after the nsec value, or we may loop ceaselessly
+		 * because the timer times out, but we haven't reached the nsec
+		 * timeout yet.
+		 */
+		t_j++;
 
-		if (sp->need_resend) {
-			;
-		} else if (time_after_eq(jiffies + 1, sp->resend_at)) {
-			sp->need_resend = true;
-			resend |= 1;
-		} else if (resend & 2) {
-			if (time_before(sp->resend_at, resend_at))
-				resend_at = sp->resend_at;
-		} else {
-			resend_at = sp->resend_at;
-			resend |= 2;
+		if (call->timer.expires != t_j || !timer_pending(&call->timer)) {
+			mod_timer(&call->timer, t_j);
+			trace_rxrpc_timer(call, why, now, now_j);
 		}
+
+		if (queue)
+			rxrpc_queue_call(call);
 	}
 
-	rxrpc_set_resend(call, resend, resend_at);
-	_leave("");
+out:
+	read_unlock_bh(&call->state_lock);
 }
 
 /*
- * process soft ACKs of our transmitted packets
- * - these indicate packets the peer has or has not received, but hasn't yet
- *   given to the consumer, and so can still be discarded and re-requested
+ * propose an ACK be sent
  */
-static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
-				   struct rxrpc_ackpacket *ack,
-				   struct sk_buff *skb)
+static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
+				u16 skew, u32 serial, bool immediate,
+				bool background,
+				enum rxrpc_propose_ack_trace why)
 {
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *txb;
-	unsigned long *p_txb, resend_at;
-	int loop;
-	u8 sacks[RXRPC_MAXACKS], resend;
-
-	_enter("{%d,%d},{%d},",
-	       call->acks_hard,
-	       CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
-	       ack->nAcks);
-
-	if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
-		goto protocol_error;
-
-	resend = 0;
-	resend_at = 0;
-	for (loop = 0; loop < ack->nAcks; loop++) {
-		p_txb = call->acks_window;
-		p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
-		smp_read_barrier_depends();
-		txb = (struct sk_buff *) (*p_txb & ~1);
-		sp = rxrpc_skb(txb);
-
-		switch (sacks[loop]) {
-		case RXRPC_ACK_TYPE_ACK:
-			sp->need_resend = false;
-			*p_txb |= 1;
-			break;
-		case RXRPC_ACK_TYPE_NACK:
-			sp->need_resend = true;
-			*p_txb &= ~1;
-			resend = 1;
-			break;
-		default:
-			_debug("Unsupported ACK type %d", sacks[loop]);
-			goto protocol_error;
-		}
-	}
-
-	smp_mb();
-	call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
-
-	/* anything not explicitly ACK'd is implicitly NACK'd, but may just not
-	 * have been received or processed yet by the far end */
-	for (loop = call->acks_unacked;
-	     loop != call->acks_head;
-	     loop = (loop + 1) &  (call->acks_winsz - 1)
-	     ) {
-		p_txb = call->acks_window + loop;
-		smp_read_barrier_depends();
-		txb = (struct sk_buff *) (*p_txb & ~1);
-		sp = rxrpc_skb(txb);
+	enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
+	unsigned int expiry = rxrpc_soft_ack_delay;
+	ktime_t now, ack_at;
+	s8 prior = rxrpc_ack_priority[ack_reason];
 
-		if (*p_txb & 1) {
-			/* packet must have been discarded */
-			sp->need_resend = true;
-			*p_txb &= ~1;
-			resend |= 1;
-		} else if (sp->need_resend) {
-			;
-		} else if (time_after_eq(jiffies + 1, sp->resend_at)) {
-			sp->need_resend = true;
-			resend |= 1;
-		} else if (resend & 2) {
-			if (time_before(sp->resend_at, resend_at))
-				resend_at = sp->resend_at;
-		} else {
-			resend_at = sp->resend_at;
-			resend |= 2;
+	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
+	 * numbers, but we don't alter the timeout.
+	 */
+	_debug("prior %u %u vs %u %u",
+	       ack_reason, prior,
+	       call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);
+	if (ack_reason == call->ackr_reason) {
+		if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
+			outcome = rxrpc_propose_ack_update;
+			call->ackr_serial = serial;
+			call->ackr_skew = skew;
 		}
+		if (!immediate)
+			goto trace;
+	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
+		call->ackr_reason = ack_reason;
+		call->ackr_serial = serial;
+		call->ackr_skew = skew;
+	} else {
+		outcome = rxrpc_propose_ack_subsume;
 	}
 
-	rxrpc_set_resend(call, resend, resend_at);
-	_leave(" = 0");
-	return 0;
-
-protocol_error:
-	_leave(" = -EPROTO");
-	return -EPROTO;
-}
-
-/*
- * discard hard-ACK'd packets from the Tx window
- */
-static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
-{
-	unsigned long _skb;
-	int tail = call->acks_tail, old_tail;
-	int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
+	switch (ack_reason) {
+	case RXRPC_ACK_REQUESTED:
+		if (rxrpc_requested_ack_delay < expiry)
+			expiry = rxrpc_requested_ack_delay;
+		if (serial == 1)
+			immediate = false;
+		break;
 
-	_enter("{%u,%u},%u", call->acks_hard, win, hard);
+	case RXRPC_ACK_DELAY:
+		if (rxrpc_soft_ack_delay < expiry)
+			expiry = rxrpc_soft_ack_delay;
+		break;
 
-	ASSERTCMP(hard - call->acks_hard, <=, win);
+	case RXRPC_ACK_PING:
+	case RXRPC_ACK_IDLE:
+		if (rxrpc_idle_ack_delay < expiry)
+			expiry = rxrpc_idle_ack_delay;
+		break;
 
-	while (call->acks_hard < hard) {
-		smp_read_barrier_depends();
-		_skb = call->acks_window[tail] & ~1;
-		rxrpc_free_skb((struct sk_buff *) _skb);
-		old_tail = tail;
-		tail = (tail + 1) & (call->acks_winsz - 1);
-		call->acks_tail = tail;
-		if (call->acks_unacked == old_tail)
-			call->acks_unacked = tail;
-		call->acks_hard++;
+	default:
+		immediate = true;
+		break;
 	}
 
-	wake_up(&call->tx_waitq);
-}
-
-/*
- * clear the Tx window in the event of a failure
- */
-static void rxrpc_clear_tx_window(struct rxrpc_call *call)
-{
-	rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
-}
-
-/*
- * drain the out of sequence received packet queue into the packet Rx queue
- */
-static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
-{
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *skb;
-	bool terminal;
-	int ret;
-
-	_enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
-
-	spin_lock_bh(&call->lock);
-
-	ret = -ECONNRESET;
-	if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
-		goto socket_unavailable;
-
-	skb = skb_dequeue(&call->rx_oos_queue);
-	if (skb) {
-		sp = rxrpc_skb(skb);
-
-		_debug("drain OOS packet %d [%d]",
-		       sp->hdr.seq, call->rx_first_oos);
-
-		if (sp->hdr.seq != call->rx_first_oos) {
-			skb_queue_head(&call->rx_oos_queue, skb);
-			call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
-			_debug("requeue %p {%u}", skb, call->rx_first_oos);
-		} else {
-			skb->mark = RXRPC_SKB_MARK_DATA;
-			terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
-				!(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
-			ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
-			BUG_ON(ret < 0);
-			_debug("drain #%u", call->rx_data_post);
-			call->rx_data_post++;
-
-			/* find out what the next packet is */
-			skb = skb_peek(&call->rx_oos_queue);
-			if (skb)
-				call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
-			else
-				call->rx_first_oos = 0;
-			_debug("peek %p {%u}", skb, call->rx_first_oos);
+	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
+		_debug("already scheduled");
+	} else if (immediate || expiry == 0) {
+		_debug("immediate ACK %lx", call->events);
+		if (!test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events) &&
+		    background)
+			rxrpc_queue_call(call);
+	} else {
+		now = ktime_get_real();
+		ack_at = ktime_add_ms(now, expiry);
+		if (ktime_before(ack_at, call->ack_at)) {
+			call->ack_at = ack_at;
+			rxrpc_set_timer(call, rxrpc_timer_set_for_ack, now);
 		}
 	}
 
-	ret = 0;
-socket_unavailable:
-	spin_unlock_bh(&call->lock);
-	_leave(" = %d", ret);
-	return ret;
+trace:
+	trace_rxrpc_propose_ack(call, why, ack_reason, serial, immediate,
+				background, outcome);
 }
 
 /*
- * insert an out of sequence packet into the buffer
+ * propose an ACK be sent, locking the call structure
  */
-static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
-				    struct sk_buff *skb)
+void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
+		       u16 skew, u32 serial, bool immediate, bool background,
+		       enum rxrpc_propose_ack_trace why)
 {
-	struct rxrpc_skb_priv *sp, *psp;
-	struct sk_buff *p;
-	u32 seq;
-
-	sp = rxrpc_skb(skb);
-	seq = sp->hdr.seq;
-	_enter(",,{%u}", seq);
-
-	skb->destructor = rxrpc_packet_destructor;
-	ASSERTCMP(sp->call, ==, NULL);
-	sp->call = call;
-	rxrpc_get_call(call);
-	atomic_inc(&call->skb_count);
-
-	/* insert into the buffer in sequence order */
 	spin_lock_bh(&call->lock);
-
-	skb_queue_walk(&call->rx_oos_queue, p) {
-		psp = rxrpc_skb(p);
-		if (psp->hdr.seq > seq) {
-			_debug("insert oos #%u before #%u", seq, psp->hdr.seq);
-			skb_insert(p, skb, &call->rx_oos_queue);
-			goto inserted;
-		}
-	}
-
-	_debug("append oos #%u", seq);
-	skb_queue_tail(&call->rx_oos_queue, skb);
-inserted:
-
-	/* we might now have a new front to the queue */
-	if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
-		call->rx_first_oos = seq;
-
-	read_lock(&call->state_lock);
-	if (call->state < RXRPC_CALL_COMPLETE &&
-	    call->rx_data_post == call->rx_first_oos) {
-		_debug("drain rx oos now");
-		set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events);
-	}
-	read_unlock(&call->state_lock);
-
+	__rxrpc_propose_ACK(call, ack_reason, skew, serial,
+			    immediate, background, why);
 	spin_unlock_bh(&call->lock);
-	_leave(" [stored #%u]", call->rx_first_oos);
-}
-
-/*
- * clear the Tx window on final ACK reception
- */
-static void rxrpc_zap_tx_window(struct rxrpc_call *call)
-{
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *skb;
-	unsigned long _skb, *acks_window;
-	u8 winsz = call->acks_winsz;
-	int tail;
-
-	acks_window = call->acks_window;
-	call->acks_window = NULL;
-
-	while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
-		tail = call->acks_tail;
-		smp_read_barrier_depends();
-		_skb = acks_window[tail] & ~1;
-		smp_mb();
-		call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
-
-		skb = (struct sk_buff *) _skb;
-		sp = rxrpc_skb(skb);
-		_debug("+++ clear Tx %u", sp->hdr.seq);
-		rxrpc_free_skb(skb);
-	}
-
-	kfree(acks_window);
 }
 
 /*
- * process the extra information that may be appended to an ACK packet
+ * Handle congestion being detected by the retransmit timeout.
  */
-static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
-				  unsigned int latest, int nAcks)
+static void rxrpc_congestion_timeout(struct rxrpc_call *call)
 {
-	struct rxrpc_ackinfo ackinfo;
-	struct rxrpc_peer *peer;
-	unsigned int mtu;
-
-	if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
-		_leave(" [no ackinfo]");
-		return;
-	}
-
-	_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
-	       latest,
-	       ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
-	       ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
-
-	mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
-
-	peer = call->conn->params.peer;
-	if (mtu < peer->maxdata) {
-		spin_lock_bh(&peer->lock);
-		peer->maxdata = mtu;
-		peer->mtu = mtu + peer->hdrsize;
-		spin_unlock_bh(&peer->lock);
-		_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
-	}
+	set_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags);
 }
 
 /*
- * process packets in the reception queue
+ * Perform retransmission of NAK'd and unack'd packets.
  */
-static int rxrpc_process_rx_queue(struct rxrpc_call *call,
-				  u32 *_abort_code)
+static void rxrpc_resend(struct rxrpc_call *call, ktime_t now)
 {
-	struct rxrpc_ackpacket ack;
 	struct rxrpc_skb_priv *sp;
 	struct sk_buff *skb;
-	bool post_ACK;
-	int latest;
-	u32 hard, tx;
-
-	_enter("");
-
-process_further:
-	skb = skb_dequeue(&call->rx_queue);
-	if (!skb)
-		return -EAGAIN;
-
-	_net("deferred skb %p", skb);
-
-	sp = rxrpc_skb(skb);
-
-	_debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
-
-	post_ACK = false;
-
-	switch (sp->hdr.type) {
-		/* data packets that wind up here have been received out of
-		 * order, need security processing or are jumbo packets */
-	case RXRPC_PACKET_TYPE_DATA:
-		_proto("OOSQ DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
+	rxrpc_seq_t cursor, seq, top;
+	ktime_t max_age, oldest, ack_ts;
+	int ix;
+	u8 annotation, anno_type, retrans = 0, unacked = 0;
 
-		/* secured packets must be verified and possibly decrypted */
-		if (call->conn->security->verify_packet(call, skb,
-							_abort_code) < 0)
-			goto protocol_error;
-
-		rxrpc_insert_oos_packet(call, skb);
-		goto process_further;
-
-		/* partial ACK to process */
-	case RXRPC_PACKET_TYPE_ACK:
-		if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
-			_debug("extraction failure");
-			goto protocol_error;
-		}
-		if (!skb_pull(skb, sizeof(ack)))
-			BUG();
-
-		latest = sp->hdr.serial;
-		hard = ntohl(ack.firstPacket);
-		tx = atomic_read(&call->sequence);
-
-		_proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
-		       latest,
-		       ntohs(ack.maxSkew),
-		       hard,
-		       ntohl(ack.previousPacket),
-		       ntohl(ack.serial),
-		       rxrpc_acks(ack.reason),
-		       ack.nAcks);
-
-		rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
-
-		if (ack.reason == RXRPC_ACK_PING) {
-			_proto("Rx ACK %%%u PING Request", latest);
-			rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
-					  sp->hdr.serial, true);
-		}
-
-		/* discard any out-of-order or duplicate ACKs */
-		if (latest - call->acks_latest <= 0) {
-			_debug("discard ACK %d <= %d",
-			       latest, call->acks_latest);
-			goto discard;
-		}
-		call->acks_latest = latest;
+	_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
 
-		if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
-		    call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
-		    call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
-		    call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
-			goto discard;
+	max_age = ktime_sub_ms(now, rxrpc_resend_timeout);
 
-		_debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
-
-		if (hard > 0) {
-			if (hard - 1 > tx) {
-				_debug("hard-ACK'd packet %d not transmitted"
-				       " (%d top)",
-				       hard - 1, tx);
-				goto protocol_error;
-			}
+	spin_lock_bh(&call->lock);
 
-			if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
-			     call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
-			    hard > tx) {
-				call->acks_hard = tx;
-				goto all_acked;
-			}
+	cursor = call->tx_hard_ack;
+	top = call->tx_top;
+	ASSERT(before_eq(cursor, top));
+	if (cursor == top)
+		goto out_unlock;
+
+	/* Scan the packet list without dropping the lock and decide which of
+	 * the packets in the Tx buffer we're going to resend and what the new
+	 * resend timeout will be.
+	 */
+	oldest = now;
+	for (seq = cursor + 1; before_eq(seq, top); seq++) {
+		ix = seq & RXRPC_RXTX_BUFF_MASK;
+		annotation = call->rxtx_annotations[ix];
+		anno_type = annotation & RXRPC_TX_ANNO_MASK;
+		annotation &= ~RXRPC_TX_ANNO_MASK;
+		if (anno_type == RXRPC_TX_ANNO_ACK)
+			continue;
 
-			smp_rmb();
-			rxrpc_rotate_tx_window(call, hard - 1);
-		}
+		skb = call->rxtx_buffer[ix];
+		rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
+		sp = rxrpc_skb(skb);
 
-		if (ack.nAcks > 0) {
-			if (hard - 1 + ack.nAcks > tx) {
-				_debug("soft-ACK'd packet %d+%d not"
-				       " transmitted (%d top)",
-				       hard - 1, ack.nAcks, tx);
-				goto protocol_error;
+		if (anno_type == RXRPC_TX_ANNO_UNACK) {
+			if (ktime_after(skb->tstamp, max_age)) {
+				if (ktime_before(skb->tstamp, oldest))
+					oldest = skb->tstamp;
+				continue;
 			}
-
-			if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
-				goto protocol_error;
+			if (!(annotation & RXRPC_TX_ANNO_RESENT))
+				unacked++;
 		}
-		goto discard;
-
-		/* complete ACK to process */
-	case RXRPC_PACKET_TYPE_ACKALL:
-		goto all_acked;
-
-		/* abort and busy are handled elsewhere */
-	case RXRPC_PACKET_TYPE_BUSY:
-	case RXRPC_PACKET_TYPE_ABORT:
-		BUG();
 
-		/* connection level events - also handled elsewhere */
-	case RXRPC_PACKET_TYPE_CHALLENGE:
-	case RXRPC_PACKET_TYPE_RESPONSE:
-	case RXRPC_PACKET_TYPE_DEBUG:
-		BUG();
+		/* Okay, we need to retransmit a packet. */
+		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
+		retrans++;
+		trace_rxrpc_retransmit(call, seq, annotation | anno_type,
+				       ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
 	}
 
-	/* if we've had a hard ACK that covers all the packets we've sent, then
-	 * that ends that phase of the operation */
-all_acked:
-	write_lock_bh(&call->state_lock);
-	_debug("ack all %d", call->state);
+	call->resend_at = ktime_add_ms(oldest, rxrpc_resend_timeout);
 
-	switch (call->state) {
-	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
-		call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
-		break;
-	case RXRPC_CALL_SERVER_AWAIT_ACK:
-		_debug("srv complete");
-		call->state = RXRPC_CALL_COMPLETE;
-		post_ACK = true;
-		break;
-	case RXRPC_CALL_CLIENT_SEND_REQUEST:
-	case RXRPC_CALL_SERVER_RECV_REQUEST:
-		goto protocol_error_unlock; /* can't occur yet */
-	default:
-		write_unlock_bh(&call->state_lock);
-		goto discard; /* assume packet left over from earlier phase */
-	}
-
-	write_unlock_bh(&call->state_lock);
+	if (unacked)
+		rxrpc_congestion_timeout(call);
 
-	/* if all the packets we sent are hard-ACK'd, then we can discard
-	 * whatever we've got left */
-	_debug("clear Tx %d",
-	       CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
-
-	del_timer_sync(&call->resend_timer);
-	clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-	clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
-
-	if (call->acks_window)
-		rxrpc_zap_tx_window(call);
-
-	if (post_ACK) {
-		/* post the final ACK message for userspace to pick up */
-		_debug("post ACK");
-		skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
-		sp->call = call;
-		rxrpc_get_call(call);
-		atomic_inc(&call->skb_count);
-		spin_lock_bh(&call->lock);
-		if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
-			BUG();
+	/* If there was nothing that needed retransmission then it's likely
+	 * that an ACK got lost somewhere.  Send a ping to find out instead of
+	 * retransmitting data.
+	 */
+	if (!retrans) {
+		rxrpc_set_timer(call, rxrpc_timer_set_for_resend, now);
 		spin_unlock_bh(&call->lock);
-		goto process_further;
-	}
-
-discard:
-	rxrpc_free_skb(skb);
-	goto process_further;
-
-protocol_error_unlock:
-	write_unlock_bh(&call->state_lock);
-protocol_error:
-	rxrpc_free_skb(skb);
-	_leave(" = -EPROTO");
-	return -EPROTO;
-}
-
-/*
- * post a message to the socket Rx queue for recvmsg() to pick up
- */
-static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
-			      bool fatal)
-{
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *skb;
-	int ret;
-
-	_enter("{%d,%lx},%u,%u,%d",
-	       call->debug_id, call->flags, mark, error, fatal);
-
-	/* remove timers and things for fatal messages */
-	if (fatal) {
-		del_timer_sync(&call->resend_timer);
-		del_timer_sync(&call->ack_timer);
-		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-	}
+		ack_ts = ktime_sub(now, call->acks_latest_ts);
+		if (ktime_to_ns(ack_ts) < call->peer->rtt)
+			goto out;
+		rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
+				  rxrpc_propose_ack_ping_for_lost_ack);
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+		goto out;
+	}
+
+	/* Now go through the Tx window and perform the retransmissions.  We
+	 * have to drop the lock for each send.  If an ACK comes in whilst the
+	 * lock is dropped, it may clear some of the retransmission markers for
+	 * packets that it soft-ACKs.
+	 */
+	for (seq = cursor + 1; before_eq(seq, top); seq++) {
+		ix = seq & RXRPC_RXTX_BUFF_MASK;
+		annotation = call->rxtx_annotations[ix];
+		anno_type = annotation & RXRPC_TX_ANNO_MASK;
+		if (anno_type != RXRPC_TX_ANNO_RETRANS)
+			continue;
 
-	if (mark != RXRPC_SKB_MARK_NEW_CALL &&
-	    !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
-		_leave("[no userid]");
-		return 0;
-	}
+		skb = call->rxtx_buffer[ix];
+		rxrpc_get_skb(skb, rxrpc_skb_tx_got);
+		spin_unlock_bh(&call->lock);
 
-	if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
-		skb = alloc_skb(0, GFP_NOFS);
-		if (!skb)
-			return -ENOMEM;
+		if (rxrpc_send_data_packet(call, skb, true) < 0) {
+			rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+			return;
+		}
 
-		rxrpc_new_skb(skb);
+		if (rxrpc_is_client_call(call))
+			rxrpc_expose_client_call(call);
 
-		skb->mark = mark;
+		rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+		spin_lock_bh(&call->lock);
 
-		sp = rxrpc_skb(skb);
-		memset(sp, 0, sizeof(*sp));
-		sp->error = error;
-		sp->call = call;
-		rxrpc_get_call(call);
-		atomic_inc(&call->skb_count);
+		/* We need to clear the retransmit state, but there are two
+		 * things we need to be aware of: A new ACK/NAK might have been
+		 * received and the packet might have been hard-ACK'd (in which
+		 * case it will no longer be in the buffer).
+		 */
+		if (after(seq, call->tx_hard_ack)) {
+			annotation = call->rxtx_annotations[ix];
+			anno_type = annotation & RXRPC_TX_ANNO_MASK;
+			if (anno_type == RXRPC_TX_ANNO_RETRANS ||
+			    anno_type == RXRPC_TX_ANNO_NAK) {
+				annotation &= ~RXRPC_TX_ANNO_MASK;
+				annotation |= RXRPC_TX_ANNO_UNACK;
+			}
+			annotation |= RXRPC_TX_ANNO_RESENT;
+			call->rxtx_annotations[ix] = annotation;
+		}
 
-		spin_lock_bh(&call->lock);
-		ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
-		spin_unlock_bh(&call->lock);
-		BUG_ON(ret < 0);
+		if (after(call->tx_hard_ack, seq))
+			seq = call->tx_hard_ack;
 	}
 
-	return 0;
+out_unlock:
+	spin_unlock_bh(&call->lock);
+out:
+	_leave("");
 }
 
 /*
- * handle background processing of incoming call packets and ACK / abort
- * generation
+ * Handle retransmission and deferred ACK/abort generation.
  */
 void rxrpc_process_call(struct work_struct *work)
 {
 	struct rxrpc_call *call =
 		container_of(work, struct rxrpc_call, processor);
-	struct rxrpc_wire_header whdr;
-	struct rxrpc_ackpacket ack;
-	struct rxrpc_ackinfo ackinfo;
-	struct msghdr msg;
-	struct kvec iov[5];
-	enum rxrpc_call_event genbit;
-	unsigned long bits;
-	__be32 data, pad;
-	size_t len;
-	int loop, nbit, ioc, ret, mtu;
-	u32 serial, abort_code = RX_PROTOCOL_ERROR;
-	u8 *acks = NULL;
-
-	//printk("\n--------------------\n");
-	_enter("{%d,%s,%lx} [%lu]",
-	       call->debug_id, rxrpc_call_states[call->state], call->events,
-	       (jiffies - call->creation_jif) / (HZ / 10));
-
-	if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
-		_debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
-		return;
-	}
-
-	if (!call->conn)
-		goto skip_msg_init;
-
-	/* there's a good chance we're going to have to send a message, so set
-	 * one up in advance */
-	msg.msg_name	= &call->conn->params.peer->srx.transport;
-	msg.msg_namelen	= call->conn->params.peer->srx.transport_len;
-	msg.msg_control	= NULL;
-	msg.msg_controllen = 0;
-	msg.msg_flags	= 0;
-
-	whdr.epoch	= htonl(call->conn->proto.epoch);
-	whdr.cid	= htonl(call->cid);
-	whdr.callNumber	= htonl(call->call_id);
-	whdr.seq	= 0;
-	whdr.type	= RXRPC_PACKET_TYPE_ACK;
-	whdr.flags	= call->conn->out_clientflag;
-	whdr.userStatus	= 0;
-	whdr.securityIndex = call->conn->security_ix;
-	whdr._rsvd	= 0;
-	whdr.serviceId	= htons(call->service_id);
-
-	memset(iov, 0, sizeof(iov));
-	iov[0].iov_base	= &whdr;
-	iov[0].iov_len	= sizeof(whdr);
-skip_msg_init:
-
-	/* deal with events of a final nature */
-	if (test_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events)) {
-		enum rxrpc_skb_mark mark;
-		int error;
-
-		clear_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
-		clear_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events);
-		clear_bit(RXRPC_CALL_EV_ABORT, &call->events);
-
-		error = call->error_report;
-		if (error < RXRPC_LOCAL_ERROR_OFFSET) {
-			mark = RXRPC_SKB_MARK_NET_ERROR;
-			_debug("post net error %d", error);
-		} else {
-			mark = RXRPC_SKB_MARK_LOCAL_ERROR;
-			error -= RXRPC_LOCAL_ERROR_OFFSET;
-			_debug("post net local error %d", error);
-		}
-
-		if (rxrpc_post_message(call, mark, error, true) < 0)
-			goto no_mem;
-		clear_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
-		goto kill_ACKs;
-	}
-
-	if (test_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events)) {
-		ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
-
-		clear_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events);
-		clear_bit(RXRPC_CALL_EV_ABORT, &call->events);
+	ktime_t now;
 
-		_debug("post conn abort");
+	rxrpc_see_call(call);
 
-		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
-				       call->conn->error, true) < 0)
-			goto no_mem;
-		clear_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
-		goto kill_ACKs;
-	}
-
-	if (test_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events)) {
-		whdr.type = RXRPC_PACKET_TYPE_BUSY;
-		genbit = RXRPC_CALL_EV_REJECT_BUSY;
-		goto send_message;
-	}
-
-	if (test_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
-		ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
-
-		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
-				       ECONNABORTED, true) < 0)
-			goto no_mem;
-		whdr.type = RXRPC_PACKET_TYPE_ABORT;
-		data = htonl(call->local_abort);
-		iov[1].iov_base = &data;
-		iov[1].iov_len = sizeof(data);
-		genbit = RXRPC_CALL_EV_ABORT;
-		goto send_message;
-	}
-
-	if (test_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events)) {
-		genbit = RXRPC_CALL_EV_ACK_FINAL;
-
-		ack.bufferSpace	= htons(8);
-		ack.maxSkew	= 0;
-		ack.serial	= 0;
-		ack.reason	= RXRPC_ACK_IDLE;
-		ack.nAcks	= 0;
-		call->ackr_reason = 0;
-
-		spin_lock_bh(&call->lock);
-		ack.serial	= htonl(call->ackr_serial);
-		ack.previousPacket = htonl(call->ackr_prev_seq);
-		ack.firstPacket	= htonl(call->rx_data_eaten + 1);
-		spin_unlock_bh(&call->lock);
-
-		pad = 0;
+	//printk("\n--------------------\n");
+	_enter("{%d,%s,%lx}",
+	       call->debug_id, rxrpc_call_states[call->state], call->events);
 
-		iov[1].iov_base = &ack;
-		iov[1].iov_len	= sizeof(ack);
-		iov[2].iov_base = &pad;
-		iov[2].iov_len	= 3;
-		iov[3].iov_base = &ackinfo;
-		iov[3].iov_len	= sizeof(ackinfo);
-		goto send_ACK;
+recheck_state:
+	if (test_and_clear_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
+		goto recheck_state;
 	}
 
-	if (call->events & ((1 << RXRPC_CALL_EV_RCVD_BUSY) |
-			    (1 << RXRPC_CALL_EV_RCVD_ABORT))
-	    ) {
-		u32 mark;
-
-		if (test_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events))
-			mark = RXRPC_SKB_MARK_REMOTE_ABORT;
-		else
-			mark = RXRPC_SKB_MARK_BUSY;
-
-		_debug("post abort/busy");
-		rxrpc_clear_tx_window(call);
-		if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
-			goto no_mem;
-
-		clear_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
-		clear_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
-		goto kill_ACKs;
+	if (call->state == RXRPC_CALL_COMPLETE) {
+		del_timer_sync(&call->timer);
+		goto out_put;
 	}
 
-	if (test_and_clear_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events)) {
-		_debug("do implicit ackall");
-		rxrpc_clear_tx_window(call);
+	now = ktime_get_real();
+	if (ktime_before(call->expire_at, now)) {
+		rxrpc_abort_call("EXP", call, 0, RX_CALL_TIMEOUT, ETIME);
+		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
+		goto recheck_state;
 	}
 
-	if (test_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events)) {
-		write_lock_bh(&call->state_lock);
-		if (call->state <= RXRPC_CALL_COMPLETE) {
-			call->state = RXRPC_CALL_LOCALLY_ABORTED;
-			call->local_abort = RX_CALL_TIMEOUT;
-			set_bit(RXRPC_CALL_EV_ABORT, &call->events);
+	if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events)) {
+		call->ack_at = call->expire_at;
+		if (call->ackr_reason) {
+			rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+			goto recheck_state;
 		}
-		write_unlock_bh(&call->state_lock);
-
-		_debug("post timeout");
-		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
-				       ETIME, true) < 0)
-			goto no_mem;
-
-		clear_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events);
-		goto kill_ACKs;
 	}
 
-	/* deal with assorted inbound messages */
-	if (!skb_queue_empty(&call->rx_queue)) {
-		switch (rxrpc_process_rx_queue(call, &abort_code)) {
-		case 0:
-		case -EAGAIN:
-			break;
-		case -ENOMEM:
-			goto no_mem;
-		case -EKEYEXPIRED:
-		case -EKEYREJECTED:
-		case -EPROTO:
-			rxrpc_abort_call(call, abort_code);
-			goto kill_ACKs;
-		}
+	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
+		rxrpc_resend(call, now);
+		goto recheck_state;
 	}
 
-	/* handle resending */
-	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
-		rxrpc_resend_timer(call);
-	if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events))
-		rxrpc_resend(call);
-
-	/* consider sending an ordinary ACK */
-	if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
-		_debug("send ACK: window: %d - %d { %lx }",
-		       call->rx_data_eaten, call->ackr_win_top,
-		       call->ackr_window[0]);
-
-		if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
-		    call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
-			/* ACK by sending reply DATA packet in this state */
-			clear_bit(RXRPC_CALL_EV_ACK, &call->events);
-			goto maybe_reschedule;
-		}
-
-		genbit = RXRPC_CALL_EV_ACK;
-
-		acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
-			       GFP_NOFS);
-		if (!acks)
-			goto no_mem;
-
-		//hdr.flags	= RXRPC_SLOW_START_OK;
-		ack.bufferSpace	= htons(8);
-		ack.maxSkew	= 0;
-
-		spin_lock_bh(&call->lock);
-		ack.reason	= call->ackr_reason;
-		ack.serial	= htonl(call->ackr_serial);
-		ack.previousPacket = htonl(call->ackr_prev_seq);
-		ack.firstPacket = htonl(call->rx_data_eaten + 1);
-
-		ack.nAcks = 0;
-		for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
-			nbit = loop * BITS_PER_LONG;
-			for (bits = call->ackr_window[loop]; bits; bits >>= 1
-			     ) {
-				_debug("- l=%d n=%d b=%lx", loop, nbit, bits);
-				if (bits & 1) {
-					acks[nbit] = RXRPC_ACK_TYPE_ACK;
-					ack.nAcks = nbit + 1;
-				}
-				nbit++;
-			}
-		}
-		call->ackr_reason = 0;
-		spin_unlock_bh(&call->lock);
-
-		pad = 0;
-
-		iov[1].iov_base = &ack;
-		iov[1].iov_len	= sizeof(ack);
-		iov[2].iov_base = acks;
-		iov[2].iov_len	= ack.nAcks;
-		iov[3].iov_base = &pad;
-		iov[3].iov_len	= 3;
-		iov[4].iov_base = &ackinfo;
-		iov[4].iov_len	= sizeof(ackinfo);
-
-		switch (ack.reason) {
-		case RXRPC_ACK_REQUESTED:
-		case RXRPC_ACK_DUPLICATE:
-		case RXRPC_ACK_OUT_OF_SEQUENCE:
-		case RXRPC_ACK_EXCEEDS_WINDOW:
-		case RXRPC_ACK_NOSPACE:
-		case RXRPC_ACK_PING:
-		case RXRPC_ACK_PING_RESPONSE:
-			goto send_ACK_with_skew;
-		case RXRPC_ACK_DELAY:
-		case RXRPC_ACK_IDLE:
-			goto send_ACK;
-		}
-	}
-
-	/* handle completion of security negotiations on an incoming
-	 * connection */
-	if (test_and_clear_bit(RXRPC_CALL_EV_SECURED, &call->events)) {
-		_debug("secured");
-		spin_lock_bh(&call->lock);
-
-		if (call->state == RXRPC_CALL_SERVER_SECURING) {
-			_debug("securing");
-			write_lock(&call->socket->call_lock);
-			if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-			    !test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
-				_debug("not released");
-				call->state = RXRPC_CALL_SERVER_ACCEPTING;
-				list_move_tail(&call->accept_link,
-					       &call->socket->acceptq);
-			}
-			write_unlock(&call->socket->call_lock);
-			read_lock(&call->state_lock);
-			if (call->state < RXRPC_CALL_COMPLETE)
-				set_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
-			read_unlock(&call->state_lock);
-		}
-
-		spin_unlock_bh(&call->lock);
-		if (!test_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events))
-			goto maybe_reschedule;
-	}
-
-	/* post a notification of an acceptable connection to the app */
-	if (test_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events)) {
-		_debug("post accept");
-		if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
-				       0, false) < 0)
-			goto no_mem;
-		clear_bit(RXRPC_CALL_EV_POST_ACCEPT, &call->events);
-		goto maybe_reschedule;
-	}
-
-	/* handle incoming call acceptance */
-	if (test_and_clear_bit(RXRPC_CALL_EV_ACCEPTED, &call->events)) {
-		_debug("accepted");
-		ASSERTCMP(call->rx_data_post, ==, 0);
-		call->rx_data_post = 1;
-		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_COMPLETE)
-			set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events);
-		read_unlock_bh(&call->state_lock);
-	}
-
-	/* drain the out of sequence received packet queue into the packet Rx
-	 * queue */
-	if (test_and_clear_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events)) {
-		while (call->rx_data_post == call->rx_first_oos)
-			if (rxrpc_drain_rx_oos_queue(call) < 0)
-				break;
-		goto maybe_reschedule;
-	}
-
-	if (test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
-		rxrpc_release_call(call);
-		clear_bit(RXRPC_CALL_EV_RELEASE, &call->events);
-	}
+	rxrpc_set_timer(call, rxrpc_timer_set_for_resend, now);
 
 	/* other events may have been raised since we started checking */
-	goto maybe_reschedule;
-
-send_ACK_with_skew:
-	ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
-			    ntohl(ack.serial));
-send_ACK:
-	mtu = call->conn->params.peer->if_mtu;
-	mtu -= call->conn->params.peer->hdrsize;
-	ackinfo.maxMTU	= htonl(mtu);
-	ackinfo.rwind	= htonl(rxrpc_rx_window_size);
-
-	/* permit the peer to send us jumbo packets if it wants to */
-	ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
-	ackinfo.jumbo_max = htonl(rxrpc_rx_jumbo_max);
-
-	serial = atomic_inc_return(&call->conn->serial);
-	whdr.serial = htonl(serial);
-	_proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
-	       serial,
-	       ntohs(ack.maxSkew),
-	       ntohl(ack.firstPacket),
-	       ntohl(ack.previousPacket),
-	       ntohl(ack.serial),
-	       rxrpc_acks(ack.reason),
-	       ack.nAcks);
-
-	del_timer_sync(&call->ack_timer);
-	if (ack.nAcks > 0)
-		set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
-	goto send_message_2;
-
-send_message:
-	_debug("send message");
-
-	serial = atomic_inc_return(&call->conn->serial);
-	whdr.serial = htonl(serial);
-	_proto("Tx %s %%%u", rxrpc_pkts[whdr.type], serial);
-send_message_2:
-
-	len = iov[0].iov_len;
-	ioc = 1;
-	if (iov[4].iov_len) {
-		ioc = 5;
-		len += iov[4].iov_len;
-		len += iov[3].iov_len;
-		len += iov[2].iov_len;
-		len += iov[1].iov_len;
-	} else if (iov[3].iov_len) {
-		ioc = 4;
-		len += iov[3].iov_len;
-		len += iov[2].iov_len;
-		len += iov[1].iov_len;
-	} else if (iov[2].iov_len) {
-		ioc = 3;
-		len += iov[2].iov_len;
-		len += iov[1].iov_len;
-	} else if (iov[1].iov_len) {
-		ioc = 2;
-		len += iov[1].iov_len;
-	}
-
-	ret = kernel_sendmsg(call->conn->params.local->socket,
-			     &msg, iov, ioc, len);
-	if (ret < 0) {
-		_debug("sendmsg failed: %d", ret);
-		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_DEAD)
-			rxrpc_queue_call(call);
-		read_unlock_bh(&call->state_lock);
-		goto error;
-	}
-
-	switch (genbit) {
-	case RXRPC_CALL_EV_ABORT:
-		clear_bit(genbit, &call->events);
-		clear_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
-		goto kill_ACKs;
-
-	case RXRPC_CALL_EV_ACK_FINAL:
-		write_lock_bh(&call->state_lock);
-		if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
-			call->state = RXRPC_CALL_COMPLETE;
-		write_unlock_bh(&call->state_lock);
-		goto kill_ACKs;
-
-	default:
-		clear_bit(genbit, &call->events);
-		switch (call->state) {
-		case RXRPC_CALL_CLIENT_AWAIT_REPLY:
-		case RXRPC_CALL_CLIENT_RECV_REPLY:
-		case RXRPC_CALL_SERVER_RECV_REQUEST:
-		case RXRPC_CALL_SERVER_ACK_REQUEST:
-			_debug("start ACK timer");
-			rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
-					  call->ackr_serial, false);
-		default:
-			break;
-		}
-		goto maybe_reschedule;
-	}
-
-kill_ACKs:
-	del_timer_sync(&call->ack_timer);
-	if (test_and_clear_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events))
-		rxrpc_put_call(call);
-	clear_bit(RXRPC_CALL_EV_ACK, &call->events);
-
-maybe_reschedule:
-	if (call->events || !skb_queue_empty(&call->rx_queue)) {
-		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_DEAD)
-			rxrpc_queue_call(call);
-		read_unlock_bh(&call->state_lock);
-	}
-
-	/* don't leave aborted connections on the accept queue */
-	if (call->state >= RXRPC_CALL_COMPLETE &&
-	    !list_empty(&call->accept_link)) {
-		_debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
-		       call, call->events, call->flags, call->conn->proto.cid);
-
-		read_lock_bh(&call->state_lock);
-		if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-		    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-			rxrpc_queue_call(call);
-		read_unlock_bh(&call->state_lock);
-	}
-
-error:
-	clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
-	kfree(acks);
-
-	/* because we don't want two CPUs both processing the work item for one
-	 * call at the same time, we use a flag to note when it's busy; however
-	 * this means there's a race between clearing the flag and setting the
-	 * work pending bit and the work item being processed again */
-	if (call->events && !work_pending(&call->processor)) {
-		_debug("jumpstart %x", call->conn->proto.cid);
-		rxrpc_queue_call(call);
+	if (call->events && call->state < RXRPC_CALL_COMPLETE) {
+		__rxrpc_queue_call(call);
+		goto out;
 	}
 
+out_put:
+	rxrpc_put_call(call, rxrpc_call_put);
+out:
 	_leave("");
-	return;
-
-no_mem:
-	_debug("out of memory");
-	goto maybe_reschedule;
 }
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index ae057e0740f3..364b42dc3dce 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -19,23 +19,13 @@
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
-/*
- * Maximum lifetime of a call (in jiffies).
- */
-unsigned int rxrpc_max_call_lifetime = 60 * HZ;
-
-/*
- * Time till dead call expires after last use (in jiffies).
- */
-unsigned int rxrpc_dead_call_expiry = 2 * HZ;
-
 const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = {
-	[RXRPC_CALL_UNINITIALISED]		= "Uninit",
+	[RXRPC_CALL_UNINITIALISED]		= "Uninit  ",
 	[RXRPC_CALL_CLIENT_AWAIT_CONN]		= "ClWtConn",
 	[RXRPC_CALL_CLIENT_SEND_REQUEST]	= "ClSndReq",
 	[RXRPC_CALL_CLIENT_AWAIT_REPLY]		= "ClAwtRpl",
 	[RXRPC_CALL_CLIENT_RECV_REPLY]		= "ClRcvRpl",
-	[RXRPC_CALL_CLIENT_FINAL_ACK]		= "ClFnlACK",
+	[RXRPC_CALL_SERVER_PREALLOC]		= "SvPrealc",
 	[RXRPC_CALL_SERVER_SECURING]		= "SvSecure",
 	[RXRPC_CALL_SERVER_ACCEPTING]		= "SvAccept",
 	[RXRPC_CALL_SERVER_RECV_REQUEST]	= "SvRcvReq",
@@ -43,22 +33,47 @@ const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = {
 	[RXRPC_CALL_SERVER_SEND_REPLY]		= "SvSndRpl",
 	[RXRPC_CALL_SERVER_AWAIT_ACK]		= "SvAwtACK",
 	[RXRPC_CALL_COMPLETE]			= "Complete",
-	[RXRPC_CALL_SERVER_BUSY]		= "SvBusy  ",
+};
+
+const char *const rxrpc_call_completions[NR__RXRPC_CALL_COMPLETIONS] = {
+	[RXRPC_CALL_SUCCEEDED]			= "Complete",
 	[RXRPC_CALL_REMOTELY_ABORTED]		= "RmtAbort",
 	[RXRPC_CALL_LOCALLY_ABORTED]		= "LocAbort",
+	[RXRPC_CALL_LOCAL_ERROR]		= "LocError",
 	[RXRPC_CALL_NETWORK_ERROR]		= "NetError",
-	[RXRPC_CALL_DEAD]			= "Dead    ",
+};
+
+const char rxrpc_call_traces[rxrpc_call__nr_trace][4] = {
+	[rxrpc_call_new_client]		= "NWc",
+	[rxrpc_call_new_service]	= "NWs",
+	[rxrpc_call_queued]		= "QUE",
+	[rxrpc_call_queued_ref]		= "QUR",
+	[rxrpc_call_connected]		= "CON",
+	[rxrpc_call_release]		= "RLS",
+	[rxrpc_call_seen]		= "SEE",
+	[rxrpc_call_got]		= "GOT",
+	[rxrpc_call_got_userid]		= "Gus",
+	[rxrpc_call_got_kernel]		= "Gke",
+	[rxrpc_call_put]		= "PUT",
+	[rxrpc_call_put_userid]		= "Pus",
+	[rxrpc_call_put_kernel]		= "Pke",
+	[rxrpc_call_put_noqueue]	= "PNQ",
+	[rxrpc_call_error]		= "*E*",
 };
 
 struct kmem_cache *rxrpc_call_jar;
 LIST_HEAD(rxrpc_calls);
 DEFINE_RWLOCK(rxrpc_call_lock);
 
-static void rxrpc_destroy_call(struct work_struct *work);
-static void rxrpc_call_life_expired(unsigned long _call);
-static void rxrpc_dead_call_expired(unsigned long _call);
-static void rxrpc_ack_time_expired(unsigned long _call);
-static void rxrpc_resend_time_expired(unsigned long _call);
+static void rxrpc_call_timer_expired(unsigned long _call)
+{
+	struct rxrpc_call *call = (struct rxrpc_call *)_call;
+
+	_enter("%d", call->debug_id);
+
+	if (call->state < RXRPC_CALL_COMPLETE)
+		rxrpc_set_timer(call, rxrpc_timer_expired, ktime_get_real());
+}
 
 /*
  * find an extant server call
@@ -91,7 +106,7 @@ struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *rx,
 	return NULL;
 
 found_extant_call:
-	rxrpc_get_call(call);
+	rxrpc_get_call(call, rxrpc_call_got);
 	read_unlock(&rx->call_lock);
 	_leave(" = %p [%d]", call, atomic_read(&call->usage));
 	return call;
@@ -100,7 +115,7 @@ found_extant_call:
 /*
  * allocate a new call
  */
-static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
+struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
 {
 	struct rxrpc_call *call;
 
@@ -108,29 +123,25 @@ static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
 	if (!call)
 		return NULL;
 
-	call->acks_winsz = 16;
-	call->acks_window = kmalloc(call->acks_winsz * sizeof(unsigned long),
+	call->rxtx_buffer = kcalloc(RXRPC_RXTX_BUFF_SIZE,
+				    sizeof(struct sk_buff *),
 				    gfp);
-	if (!call->acks_window) {
-		kmem_cache_free(rxrpc_call_jar, call);
-		return NULL;
-	}
+	if (!call->rxtx_buffer)
+		goto nomem;
+
+	call->rxtx_annotations = kcalloc(RXRPC_RXTX_BUFF_SIZE, sizeof(u8), gfp);
+	if (!call->rxtx_annotations)
+		goto nomem_2;
 
-	setup_timer(&call->lifetimer, &rxrpc_call_life_expired,
-		    (unsigned long) call);
-	setup_timer(&call->deadspan, &rxrpc_dead_call_expired,
-		    (unsigned long) call);
-	setup_timer(&call->ack_timer, &rxrpc_ack_time_expired,
-		    (unsigned long) call);
-	setup_timer(&call->resend_timer, &rxrpc_resend_time_expired,
-		    (unsigned long) call);
-	INIT_WORK(&call->destroyer, &rxrpc_destroy_call);
+	setup_timer(&call->timer, rxrpc_call_timer_expired,
+		    (unsigned long)call);
 	INIT_WORK(&call->processor, &rxrpc_process_call);
 	INIT_LIST_HEAD(&call->link);
+	INIT_LIST_HEAD(&call->chan_wait_link);
 	INIT_LIST_HEAD(&call->accept_link);
-	skb_queue_head_init(&call->rx_queue);
-	skb_queue_head_init(&call->rx_oos_queue);
-	init_waitqueue_head(&call->tx_waitq);
+	INIT_LIST_HEAD(&call->recvmsg_link);
+	INIT_LIST_HEAD(&call->sock_link);
+	init_waitqueue_head(&call->waitq);
 	spin_lock_init(&call->lock);
 	rwlock_init(&call->state_lock);
 	atomic_set(&call->usage, 1);
@@ -138,70 +149,65 @@ static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
 
 	memset(&call->sock_node, 0xed, sizeof(call->sock_node));
 
-	call->rx_data_expect = 1;
-	call->rx_data_eaten = 0;
-	call->rx_first_oos = 0;
-	call->ackr_win_top = call->rx_data_eaten + 1 + rxrpc_rx_window_size;
-	call->creation_jif = jiffies;
+	/* Leave space in the ring to handle a maxed-out jumbo packet */
+	call->rx_winsize = rxrpc_rx_window_size;
+	call->tx_winsize = 16;
+	call->rx_expect_next = 1;
+
+	if (RXRPC_TX_SMSS > 2190)
+		call->cong_cwnd = 2;
+	else if (RXRPC_TX_SMSS > 1095)
+		call->cong_cwnd = 3;
+	else
+		call->cong_cwnd = 4;
+	call->cong_ssthresh = RXRPC_RXTX_BUFF_SIZE - 1;
 	return call;
+
+nomem_2:
+	kfree(call->rxtx_buffer);
+nomem:
+	kmem_cache_free(rxrpc_call_jar, call);
+	return NULL;
 }
 
 /*
  * Allocate a new client call.
  */
-static struct rxrpc_call *rxrpc_alloc_client_call(struct rxrpc_sock *rx,
-						  struct sockaddr_rxrpc *srx,
+static struct rxrpc_call *rxrpc_alloc_client_call(struct sockaddr_rxrpc *srx,
 						  gfp_t gfp)
 {
 	struct rxrpc_call *call;
+	ktime_t now;
 
 	_enter("");
 
-	ASSERT(rx->local != NULL);
-
 	call = rxrpc_alloc_call(gfp);
 	if (!call)
 		return ERR_PTR(-ENOMEM);
 	call->state = RXRPC_CALL_CLIENT_AWAIT_CONN;
-
-	sock_hold(&rx->sk);
-	call->socket = rx;
-	call->rx_data_post = 1;
-
-	call->local = rx->local;
 	call->service_id = srx->srx_service;
-	call->in_clientflag = 0;
+	call->tx_phase = true;
+	now = ktime_get_real();
+	call->acks_latest_ts = now;
+	call->cong_tstamp = now;
 
 	_leave(" = %p", call);
 	return call;
 }
 
 /*
- * Begin client call.
+ * Initiate the call ack/resend/expiry timer.
  */
-static int rxrpc_begin_client_call(struct rxrpc_call *call,
-				   struct rxrpc_conn_parameters *cp,
-				   struct sockaddr_rxrpc *srx,
-				   gfp_t gfp)
+static void rxrpc_start_call_timer(struct rxrpc_call *call)
 {
-	int ret;
-
-	/* Set up or get a connection record and set the protocol parameters,
-	 * including channel number and call ID.
-	 */
-	ret = rxrpc_connect_call(call, cp, srx, gfp);
-	if (ret < 0)
-		return ret;
-
-	call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
-
-	spin_lock(&call->conn->params.peer->lock);
-	hlist_add_head(&call->error_link, &call->conn->params.peer->error_targets);
-	spin_unlock(&call->conn->params.peer->lock);
-
-	call->lifetimer.expires = jiffies + rxrpc_max_call_lifetime;
-	add_timer(&call->lifetimer);
-	return 0;
+	ktime_t now = ktime_get_real(), expire_at;
+
+	expire_at = ktime_add_ms(now, rxrpc_max_call_lifetime);
+	call->expire_at = expire_at;
+	call->ack_at = expire_at;
+	call->resend_at = expire_at;
+	call->timer.expires = jiffies + LONG_MAX / 2;
+	rxrpc_set_timer(call, rxrpc_timer_begin, now);
 }
 
 /*
@@ -216,20 +222,21 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 {
 	struct rxrpc_call *call, *xcall;
 	struct rb_node *parent, **pp;
+	const void *here = __builtin_return_address(0);
 	int ret;
 
 	_enter("%p,%lx", rx, user_call_ID);
 
-	call = rxrpc_alloc_client_call(rx, srx, gfp);
+	call = rxrpc_alloc_client_call(srx, gfp);
 	if (IS_ERR(call)) {
 		_leave(" = %ld", PTR_ERR(call));
 		return call;
 	}
 
-	/* Publish the call, even though it is incompletely set up as yet */
-	call->user_call_ID = user_call_ID;
-	__set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
+	trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
+			 here, (const void *)user_call_ID);
 
+	/* Publish the call, even though it is incompletely set up as yet */
 	write_lock(&rx->call_lock);
 
 	pp = &rx->calls.rb_node;
@@ -243,369 +250,285 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 		else if (user_call_ID > xcall->user_call_ID)
 			pp = &(*pp)->rb_right;
 		else
-			goto found_user_ID_now_present;
+			goto error_dup_user_ID;
 	}
 
-	rxrpc_get_call(call);
-
+	rcu_assign_pointer(call->socket, rx);
+	call->user_call_ID = user_call_ID;
+	__set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
+	rxrpc_get_call(call, rxrpc_call_got_userid);
 	rb_link_node(&call->sock_node, parent, pp);
 	rb_insert_color(&call->sock_node, &rx->calls);
+	list_add(&call->sock_link, &rx->sock_calls);
+
 	write_unlock(&rx->call_lock);
 
-	write_lock_bh(&rxrpc_call_lock);
+	write_lock(&rxrpc_call_lock);
 	list_add_tail(&call->link, &rxrpc_calls);
-	write_unlock_bh(&rxrpc_call_lock);
+	write_unlock(&rxrpc_call_lock);
 
-	ret = rxrpc_begin_client_call(call, cp, srx, gfp);
+	/* Set up or get a connection record and set the protocol parameters,
+	 * including channel number and call ID.
+	 */
+	ret = rxrpc_connect_call(call, cp, srx, gfp);
 	if (ret < 0)
 		goto error;
 
-	_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
+	trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
+			 here, ERR_PTR(ret));
 
-	_leave(" = %p [new]", call);
-	return call;
+	spin_lock_bh(&call->conn->params.peer->lock);
+	hlist_add_head(&call->error_link,
+		       &call->conn->params.peer->error_targets);
+	spin_unlock_bh(&call->conn->params.peer->lock);
 
-error:
-	write_lock(&rx->call_lock);
-	rb_erase(&call->sock_node, &rx->calls);
-	write_unlock(&rx->call_lock);
-	rxrpc_put_call(call);
+	rxrpc_start_call_timer(call);
 
-	write_lock_bh(&rxrpc_call_lock);
-	list_del_init(&call->link);
-	write_unlock_bh(&rxrpc_call_lock);
+	_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
 
-	set_bit(RXRPC_CALL_RELEASED, &call->flags);
-	call->state = RXRPC_CALL_DEAD;
-	rxrpc_put_call(call);
-	_leave(" = %d", ret);
-	return ERR_PTR(ret);
+	_leave(" = %p [new]", call);
+	return call;
 
 	/* We unexpectedly found the user ID in the list after taking
 	 * the call_lock.  This shouldn't happen unless the user races
 	 * with itself and tries to add the same user ID twice at the
 	 * same time in different threads.
 	 */
-found_user_ID_now_present:
+error_dup_user_ID:
 	write_unlock(&rx->call_lock);
-	set_bit(RXRPC_CALL_RELEASED, &call->flags);
-	call->state = RXRPC_CALL_DEAD;
-	rxrpc_put_call(call);
-	_leave(" = -EEXIST [%p]", call);
-	return ERR_PTR(-EEXIST);
+	ret = -EEXIST;
+
+error:
+	__rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
+				    RX_CALL_DEAD, ret);
+	trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
+			 here, ERR_PTR(ret));
+	rxrpc_release_call(rx, call);
+	rxrpc_put_call(call, rxrpc_call_put);
+	_leave(" = %d", ret);
+	return ERR_PTR(ret);
 }
 
 /*
- * set up an incoming call
- * - called in process context with IRQs enabled
+ * Set up an incoming call.  call->conn points to the connection.
+ * This is called in BH context and isn't allowed to fail.
  */
-struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *rx,
-				       struct rxrpc_connection *conn,
-				       struct sk_buff *skb)
+void rxrpc_incoming_call(struct rxrpc_sock *rx,
+			 struct rxrpc_call *call,
+			 struct sk_buff *skb)
 {
+	struct rxrpc_connection *conn = call->conn;
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	struct rxrpc_call *call, *candidate;
-	u32 call_id, chan;
-
-	_enter(",%d", conn->debug_id);
-
-	ASSERT(rx != NULL);
-
-	candidate = rxrpc_alloc_call(GFP_NOIO);
-	if (!candidate)
-		return ERR_PTR(-EBUSY);
-
-	chan = sp->hdr.cid & RXRPC_CHANNELMASK;
-	candidate->socket	= rx;
-	candidate->conn		= conn;
-	candidate->cid		= sp->hdr.cid;
-	candidate->call_id	= sp->hdr.callNumber;
-	candidate->channel	= chan;
-	candidate->rx_data_post	= 0;
-	candidate->state	= RXRPC_CALL_SERVER_ACCEPTING;
-	if (conn->security_ix > 0)
-		candidate->state = RXRPC_CALL_SERVER_SECURING;
-
-	spin_lock(&conn->channel_lock);
-
-	/* set the channel for this call */
-	call = rcu_dereference_protected(conn->channels[chan].call,
-					 lockdep_is_held(&conn->channel_lock));
-
-	_debug("channel[%u] is %p", candidate->channel, call);
-	if (call && call->call_id == sp->hdr.callNumber) {
-		/* already set; must've been a duplicate packet */
-		_debug("extant call [%d]", call->state);
-		ASSERTCMP(call->conn, ==, conn);
-
-		read_lock(&call->state_lock);
-		switch (call->state) {
-		case RXRPC_CALL_LOCALLY_ABORTED:
-			if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events))
-				rxrpc_queue_call(call);
-		case RXRPC_CALL_REMOTELY_ABORTED:
-			read_unlock(&call->state_lock);
-			goto aborted_call;
-		default:
-			rxrpc_get_call(call);
-			read_unlock(&call->state_lock);
-			goto extant_call;
-		}
-	}
-
-	if (call) {
-		/* it seems the channel is still in use from the previous call
-		 * - ditch the old binding if its call is now complete */
-		_debug("CALL: %u { %s }",
-		       call->debug_id, rxrpc_call_states[call->state]);
-
-		if (call->state >= RXRPC_CALL_COMPLETE) {
-			__rxrpc_disconnect_call(call);
-		} else {
-			spin_unlock(&conn->channel_lock);
-			kmem_cache_free(rxrpc_call_jar, candidate);
-			_leave(" = -EBUSY");
-			return ERR_PTR(-EBUSY);
-		}
-	}
-
-	/* check the call number isn't duplicate */
-	_debug("check dup");
-	call_id = sp->hdr.callNumber;
-
-	/* We just ignore calls prior to the current call ID.  Terminated calls
-	 * are handled via the connection.
+	u32 chan;
+
+	_enter(",%d", call->conn->debug_id);
+
+	rcu_assign_pointer(call->socket, rx);
+	call->call_id		= sp->hdr.callNumber;
+	call->service_id	= sp->hdr.serviceId;
+	call->cid		= sp->hdr.cid;
+	call->state		= RXRPC_CALL_SERVER_ACCEPTING;
+	if (sp->hdr.securityIndex > 0)
+		call->state	= RXRPC_CALL_SERVER_SECURING;
+	call->cong_tstamp	= skb->tstamp;
+
+	/* Set the channel for this call.  We don't get channel_lock as we're
+	 * only defending against the data_ready handler (which we're called
+	 * from) and the RESPONSE packet parser (which is only really
+	 * interested in call_counter and can cope with a disagreement with the
+	 * call pointer).
 	 */
-	if (call_id <= conn->channels[chan].call_counter)
-		goto old_call; /* TODO: Just drop packet */
-
-	/* make the call available */
-	_debug("new call");
-	call = candidate;
-	candidate = NULL;
-	conn->channels[chan].call_counter = call_id;
+	chan = sp->hdr.cid & RXRPC_CHANNELMASK;
+	conn->channels[chan].call_counter = call->call_id;
+	conn->channels[chan].call_id = call->call_id;
 	rcu_assign_pointer(conn->channels[chan].call, call);
-	sock_hold(&rx->sk);
-	rxrpc_get_connection(conn);
-	spin_unlock(&conn->channel_lock);
 
 	spin_lock(&conn->params.peer->lock);
 	hlist_add_head(&call->error_link, &conn->params.peer->error_targets);
 	spin_unlock(&conn->params.peer->lock);
 
-	write_lock_bh(&rxrpc_call_lock);
-	list_add_tail(&call->link, &rxrpc_calls);
-	write_unlock_bh(&rxrpc_call_lock);
+	_net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
 
-	call->local = conn->params.local;
-	call->epoch = conn->proto.epoch;
-	call->service_id = conn->params.service_id;
-	call->in_clientflag = RXRPC_CLIENT_INITIATED;
+	rxrpc_start_call_timer(call);
+	_leave("");
+}
 
-	_net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
+/*
+ * Queue a call's work processor, getting a ref to pass to the work queue.
+ */
+bool rxrpc_queue_call(struct rxrpc_call *call)
+{
+	const void *here = __builtin_return_address(0);
+	int n = __atomic_add_unless(&call->usage, 1, 0);
+	if (n == 0)
+		return false;
+	if (rxrpc_queue_work(&call->processor))
+		trace_rxrpc_call(call, rxrpc_call_queued, n + 1, here, NULL);
+	else
+		rxrpc_put_call(call, rxrpc_call_put_noqueue);
+	return true;
+}
 
-	call->lifetimer.expires = jiffies + rxrpc_max_call_lifetime;
-	add_timer(&call->lifetimer);
-	_leave(" = %p {%d} [new]", call, call->debug_id);
-	return call;
+/*
+ * Queue a call's work processor, passing the callers ref to the work queue.
+ */
+bool __rxrpc_queue_call(struct rxrpc_call *call)
+{
+	const void *here = __builtin_return_address(0);
+	int n = atomic_read(&call->usage);
+	ASSERTCMP(n, >=, 1);
+	if (rxrpc_queue_work(&call->processor))
+		trace_rxrpc_call(call, rxrpc_call_queued_ref, n, here, NULL);
+	else
+		rxrpc_put_call(call, rxrpc_call_put_noqueue);
+	return true;
+}
 
-extant_call:
-	spin_unlock(&conn->channel_lock);
-	kmem_cache_free(rxrpc_call_jar, candidate);
-	_leave(" = %p {%d} [extant]", call, call ? call->debug_id : -1);
-	return call;
+/*
+ * Note the re-emergence of a call.
+ */
+void rxrpc_see_call(struct rxrpc_call *call)
+{
+	const void *here = __builtin_return_address(0);
+	if (call) {
+		int n = atomic_read(&call->usage);
 
-aborted_call:
-	spin_unlock(&conn->channel_lock);
-	kmem_cache_free(rxrpc_call_jar, candidate);
-	_leave(" = -ECONNABORTED");
-	return ERR_PTR(-ECONNABORTED);
-
-old_call:
-	spin_unlock(&conn->channel_lock);
-	kmem_cache_free(rxrpc_call_jar, candidate);
-	_leave(" = -ECONNRESET [old]");
-	return ERR_PTR(-ECONNRESET);
+		trace_rxrpc_call(call, rxrpc_call_seen, n, here, NULL);
+	}
 }
 
 /*
- * detach a call from a socket and set up for release
+ * Note the addition of a ref on a call.
  */
-void rxrpc_release_call(struct rxrpc_call *call)
+void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 {
+	const void *here = __builtin_return_address(0);
+	int n = atomic_inc_return(&call->usage);
+
+	trace_rxrpc_call(call, op, n, here, NULL);
+}
+
+/*
+ * Detach a call from its owning socket.
+ */
+void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
+{
+	const void *here = __builtin_return_address(0);
 	struct rxrpc_connection *conn = call->conn;
-	struct rxrpc_sock *rx = call->socket;
+	bool put = false;
+	int i;
 
-	_enter("{%d,%d,%d,%d}",
-	       call->debug_id, atomic_read(&call->usage),
-	       atomic_read(&call->ackr_not_idle),
-	       call->rx_first_oos);
+	_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
+
+	trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
+			 here, (const void *)call->flags);
+
+	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 
 	spin_lock_bh(&call->lock);
 	if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
 		BUG();
 	spin_unlock_bh(&call->lock);
 
-	/* dissociate from the socket
-	 * - the socket's ref on the call is passed to the death timer
-	 */
-	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
+	del_timer_sync(&call->timer);
 
-	spin_lock(&conn->params.peer->lock);
-	hlist_del_init(&call->error_link);
-	spin_unlock(&conn->params.peer->lock);
+	/* Make sure we don't get any more notifications */
+	write_lock_bh(&rx->recvmsg_lock);
 
-	write_lock_bh(&rx->call_lock);
-	if (!list_empty(&call->accept_link)) {
+	if (!list_empty(&call->recvmsg_link)) {
 		_debug("unlinking once-pending call %p { e=%lx f=%lx }",
 		       call, call->events, call->flags);
-		ASSERT(!test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
-		list_del_init(&call->accept_link);
-		sk_acceptq_removed(&rx->sk);
-	} else if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
-		rb_erase(&call->sock_node, &rx->calls);
-		memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
-		clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
+		list_del(&call->recvmsg_link);
+		put = true;
 	}
-	write_unlock_bh(&rx->call_lock);
 
-	/* free up the channel for reuse */
-	write_lock_bh(&call->state_lock);
+	/* list_empty() must return false in rxrpc_notify_socket() */
+	call->recvmsg_link.next = NULL;
+	call->recvmsg_link.prev = NULL;
 
-	if (call->state < RXRPC_CALL_COMPLETE &&
-	    call->state != RXRPC_CALL_CLIENT_FINAL_ACK) {
-		_debug("+++ ABORTING STATE %d +++\n", call->state);
-		call->state = RXRPC_CALL_LOCALLY_ABORTED;
-		call->local_abort = RX_CALL_DEAD;
-	}
-	write_unlock_bh(&call->state_lock);
+	write_unlock_bh(&rx->recvmsg_lock);
+	if (put)
+		rxrpc_put_call(call, rxrpc_call_put);
 
-	rxrpc_disconnect_call(call);
+	write_lock(&rx->call_lock);
 
-	/* clean up the Rx queue */
-	if (!skb_queue_empty(&call->rx_queue) ||
-	    !skb_queue_empty(&call->rx_oos_queue)) {
-		struct rxrpc_skb_priv *sp;
-		struct sk_buff *skb;
+	if (test_and_clear_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
+		rb_erase(&call->sock_node, &rx->calls);
+		memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
+		rxrpc_put_call(call, rxrpc_call_put_userid);
+	}
 
-		_debug("purge Rx queues");
+	list_del(&call->sock_link);
+	write_unlock(&rx->call_lock);
 
-		spin_lock_bh(&call->lock);
-		while ((skb = skb_dequeue(&call->rx_queue)) ||
-		       (skb = skb_dequeue(&call->rx_oos_queue))) {
-			spin_unlock_bh(&call->lock);
+	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
 
-			sp = rxrpc_skb(skb);
-			_debug("- zap %s %%%u #%u",
-			       rxrpc_pkts[sp->hdr.type],
-			       sp->hdr.serial, sp->hdr.seq);
-			rxrpc_free_skb(skb);
-			spin_lock_bh(&call->lock);
-		}
-		spin_unlock_bh(&call->lock);
+	if (conn)
+		rxrpc_disconnect_call(call);
 
-		ASSERTCMP(call->state, !=, RXRPC_CALL_COMPLETE);
+	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
+		rxrpc_free_skb(call->rxtx_buffer[i],
+			       (call->tx_phase ? rxrpc_skb_tx_cleaned :
+				rxrpc_skb_rx_cleaned));
+		call->rxtx_buffer[i] = NULL;
 	}
 
-	del_timer_sync(&call->resend_timer);
-	del_timer_sync(&call->ack_timer);
-	del_timer_sync(&call->lifetimer);
-	call->deadspan.expires = jiffies + rxrpc_dead_call_expiry;
-	add_timer(&call->deadspan);
-
 	_leave("");
 }
 
 /*
- * handle a dead call being ready for reaping
- */
-static void rxrpc_dead_call_expired(unsigned long _call)
-{
-	struct rxrpc_call *call = (struct rxrpc_call *) _call;
-
-	_enter("{%d}", call->debug_id);
-
-	write_lock_bh(&call->state_lock);
-	call->state = RXRPC_CALL_DEAD;
-	write_unlock_bh(&call->state_lock);
-	rxrpc_put_call(call);
-}
-
-/*
- * mark a call as to be released, aborting it if it's still in progress
- * - called with softirqs disabled
- */
-static void rxrpc_mark_call_released(struct rxrpc_call *call)
-{
-	bool sched;
-
-	write_lock(&call->state_lock);
-	if (call->state < RXRPC_CALL_DEAD) {
-		sched = false;
-		if (call->state < RXRPC_CALL_COMPLETE) {
-			_debug("abort call %p", call);
-			call->state = RXRPC_CALL_LOCALLY_ABORTED;
-			call->local_abort = RX_CALL_DEAD;
-			if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events))
-				sched = true;
-		}
-		if (!test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-			sched = true;
-		if (sched)
-			rxrpc_queue_call(call);
-	}
-	write_unlock(&call->state_lock);
-}
-
-/*
  * release all the calls associated with a socket
  */
 void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
 {
 	struct rxrpc_call *call;
-	struct rb_node *p;
 
 	_enter("%p", rx);
 
-	read_lock_bh(&rx->call_lock);
-
-	/* mark all the calls as no longer wanting incoming packets */
-	for (p = rb_first(&rx->calls); p; p = rb_next(p)) {
-		call = rb_entry(p, struct rxrpc_call, sock_node);
-		rxrpc_mark_call_released(call);
-	}
-
-	/* kill the not-yet-accepted incoming calls */
-	list_for_each_entry(call, &rx->secureq, accept_link) {
-		rxrpc_mark_call_released(call);
+	while (!list_empty(&rx->to_be_accepted)) {
+		call = list_entry(rx->to_be_accepted.next,
+				  struct rxrpc_call, accept_link);
+		list_del(&call->accept_link);
+		rxrpc_abort_call("SKR", call, 0, RX_CALL_DEAD, ECONNRESET);
+		rxrpc_put_call(call, rxrpc_call_put);
 	}
 
-	list_for_each_entry(call, &rx->acceptq, accept_link) {
-		rxrpc_mark_call_released(call);
+	while (!list_empty(&rx->sock_calls)) {
+		call = list_entry(rx->sock_calls.next,
+				  struct rxrpc_call, sock_link);
+		rxrpc_get_call(call, rxrpc_call_got);
+		rxrpc_abort_call("SKT", call, 0, RX_CALL_DEAD, ECONNRESET);
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
+		rxrpc_release_call(rx, call);
+		rxrpc_put_call(call, rxrpc_call_put);
 	}
 
-	read_unlock_bh(&rx->call_lock);
 	_leave("");
 }
 
 /*
  * release a call
  */
-void __rxrpc_put_call(struct rxrpc_call *call)
+void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 {
+	const void *here = __builtin_return_address(0);
+	int n;
+
 	ASSERT(call != NULL);
 
-	_enter("%p{u=%d}", call, atomic_read(&call->usage));
+	n = atomic_dec_return(&call->usage);
+	trace_rxrpc_call(call, op, n, here, NULL);
+	ASSERTCMP(n, >=, 0);
+	if (n == 0) {
+		_debug("call %d dead", call->debug_id);
+		ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 
-	ASSERTCMP(atomic_read(&call->usage), >, 0);
+		write_lock(&rxrpc_call_lock);
+		list_del_init(&call->link);
+		write_unlock(&rxrpc_call_lock);
 
-	if (atomic_dec_and_test(&call->usage)) {
-		_debug("call %d dead", call->debug_id);
-		WARN_ON(atomic_read(&call->skb_count) != 0);
-		ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
-		rxrpc_queue_work(&call->destroyer);
+		rxrpc_cleanup_call(call);
 	}
-	_leave("");
 }
 
 /*
@@ -615,187 +538,70 @@ static void rxrpc_rcu_destroy_call(struct rcu_head *rcu)
 {
 	struct rxrpc_call *call = container_of(rcu, struct rxrpc_call, rcu);
 
-	rxrpc_purge_queue(&call->rx_queue);
+	rxrpc_put_peer(call->peer);
+	kfree(call->rxtx_buffer);
+	kfree(call->rxtx_annotations);
 	kmem_cache_free(rxrpc_call_jar, call);
 }
 
 /*
  * clean up a call
  */
-static void rxrpc_cleanup_call(struct rxrpc_call *call)
+void rxrpc_cleanup_call(struct rxrpc_call *call)
 {
-	_net("DESTROY CALL %d", call->debug_id);
+	int i;
 
-	ASSERT(call->socket);
+	_net("DESTROY CALL %d", call->debug_id);
 
 	memset(&call->sock_node, 0xcd, sizeof(call->sock_node));
 
-	del_timer_sync(&call->lifetimer);
-	del_timer_sync(&call->deadspan);
-	del_timer_sync(&call->ack_timer);
-	del_timer_sync(&call->resend_timer);
+	del_timer_sync(&call->timer);
 
+	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 	ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags));
-	ASSERTCMP(call->events, ==, 0);
-	if (work_pending(&call->processor)) {
-		_debug("defer destroy");
-		rxrpc_queue_work(&call->destroyer);
-		return;
-	}
-
 	ASSERTCMP(call->conn, ==, NULL);
 
-	if (call->acks_window) {
-		_debug("kill Tx window %d",
-		       CIRC_CNT(call->acks_head, call->acks_tail,
-				call->acks_winsz));
-		smp_mb();
-		while (CIRC_CNT(call->acks_head, call->acks_tail,
-				call->acks_winsz) > 0) {
-			struct rxrpc_skb_priv *sp;
-			unsigned long _skb;
-
-			_skb = call->acks_window[call->acks_tail] & ~1;
-			sp = rxrpc_skb((struct sk_buff *)_skb);
-			_debug("+++ clear Tx %u", sp->hdr.seq);
-			rxrpc_free_skb((struct sk_buff *)_skb);
-			call->acks_tail =
-				(call->acks_tail + 1) & (call->acks_winsz - 1);
-		}
-
-		kfree(call->acks_window);
-	}
+	/* Clean up the Rx/Tx buffer */
+	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++)
+		rxrpc_free_skb(call->rxtx_buffer[i],
+			       (call->tx_phase ? rxrpc_skb_tx_cleaned :
+				rxrpc_skb_rx_cleaned));
 
-	rxrpc_free_skb(call->tx_pending);
+	rxrpc_free_skb(call->tx_pending, rxrpc_skb_tx_cleaned);
 
-	rxrpc_purge_queue(&call->rx_queue);
-	ASSERT(skb_queue_empty(&call->rx_oos_queue));
-	sock_put(&call->socket->sk);
 	call_rcu(&call->rcu, rxrpc_rcu_destroy_call);
 }
 
 /*
- * destroy a call
- */
-static void rxrpc_destroy_call(struct work_struct *work)
-{
-	struct rxrpc_call *call =
-		container_of(work, struct rxrpc_call, destroyer);
-
-	_enter("%p{%d,%d,%p}",
-	       call, atomic_read(&call->usage), call->channel, call->conn);
-
-	ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
-
-	write_lock_bh(&rxrpc_call_lock);
-	list_del_init(&call->link);
-	write_unlock_bh(&rxrpc_call_lock);
-
-	rxrpc_cleanup_call(call);
-	_leave("");
-}
-
-/*
- * preemptively destroy all the call records from a transport endpoint rather
- * than waiting for them to time out
+ * Make sure that all calls are gone.
  */
 void __exit rxrpc_destroy_all_calls(void)
 {
 	struct rxrpc_call *call;
 
 	_enter("");
-	write_lock_bh(&rxrpc_call_lock);
+
+	if (list_empty(&rxrpc_calls))
+		return;
+
+	write_lock(&rxrpc_call_lock);
 
 	while (!list_empty(&rxrpc_calls)) {
 		call = list_entry(rxrpc_calls.next, struct rxrpc_call, link);
 		_debug("Zapping call %p", call);
 
+		rxrpc_see_call(call);
 		list_del_init(&call->link);
 
-		switch (atomic_read(&call->usage)) {
-		case 0:
-			ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
-			break;
-		case 1:
-			if (del_timer_sync(&call->deadspan) != 0 &&
-			    call->state != RXRPC_CALL_DEAD)
-				rxrpc_dead_call_expired((unsigned long) call);
-			if (call->state != RXRPC_CALL_DEAD)
-				break;
-		default:
-			pr_err("Call %p still in use (%d,%d,%s,%lx,%lx)!\n",
-			       call, atomic_read(&call->usage),
-			       atomic_read(&call->ackr_not_idle),
-			       rxrpc_call_states[call->state],
-			       call->flags, call->events);
-			if (!skb_queue_empty(&call->rx_queue))
-				pr_err("Rx queue occupied\n");
-			if (!skb_queue_empty(&call->rx_oos_queue))
-				pr_err("OOS queue occupied\n");
-			break;
-		}
-
-		write_unlock_bh(&rxrpc_call_lock);
-		cond_resched();
-		write_lock_bh(&rxrpc_call_lock);
-	}
-
-	write_unlock_bh(&rxrpc_call_lock);
-	_leave("");
-}
-
-/*
- * handle call lifetime being exceeded
- */
-static void rxrpc_call_life_expired(unsigned long _call)
-{
-	struct rxrpc_call *call = (struct rxrpc_call *) _call;
+		pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n",
+		       call, atomic_read(&call->usage),
+		       rxrpc_call_states[call->state],
+		       call->flags, call->events);
 
-	if (call->state >= RXRPC_CALL_COMPLETE)
-		return;
-
-	_enter("{%d}", call->debug_id);
-	read_lock_bh(&call->state_lock);
-	if (call->state < RXRPC_CALL_COMPLETE) {
-		set_bit(RXRPC_CALL_EV_LIFE_TIMER, &call->events);
-		rxrpc_queue_call(call);
+		write_unlock(&rxrpc_call_lock);
+		cond_resched();
+		write_lock(&rxrpc_call_lock);
 	}
-	read_unlock_bh(&call->state_lock);
-}
-
-/*
- * handle resend timer expiry
- * - may not take call->state_lock as this can deadlock against del_timer_sync()
- */
-static void rxrpc_resend_time_expired(unsigned long _call)
-{
-	struct rxrpc_call *call = (struct rxrpc_call *) _call;
-
-	_enter("{%d}", call->debug_id);
-
-	if (call->state >= RXRPC_CALL_COMPLETE)
-		return;
-
-	clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-	if (!test_and_set_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
-		rxrpc_queue_call(call);
-}
-
-/*
- * handle ACK timer expiry
- */
-static void rxrpc_ack_time_expired(unsigned long _call)
-{
-	struct rxrpc_call *call = (struct rxrpc_call *) _call;
-
-	_enter("{%d}", call->debug_id);
-
-	if (call->state >= RXRPC_CALL_COMPLETE)
-		return;
 
-	read_lock_bh(&call->state_lock);
-	if (call->state < RXRPC_CALL_COMPLETE &&
-	    !test_and_set_bit(RXRPC_CALL_EV_ACK, &call->events))
-		rxrpc_queue_call(call);
-	read_unlock_bh(&call->state_lock);
+	write_unlock(&rxrpc_call_lock);
 }
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index 9e91f27b0d0f..60ef9605167e 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -7,6 +7,68 @@
  * modify it under the terms of the GNU General Public Licence
  * as published by the Free Software Foundation; either version
  * 2 of the Licence, or (at your option) any later version.
+ *
+ *
+ * Client connections need to be cached for a little while after they've made a
+ * call so as to handle retransmitted DATA packets in case the server didn't
+ * receive the final ACK or terminating ABORT we sent it.
+ *
+ * Client connections can be in one of a number of cache states:
+ *
+ *  (1) INACTIVE - The connection is not held in any list and may not have been
+ *      exposed to the world.  If it has been previously exposed, it was
+ *      discarded from the idle list after expiring.
+ *
+ *  (2) WAITING - The connection is waiting for the number of client conns to
+ *      drop below the maximum capacity.  Calls may be in progress upon it from
+ *      when it was active and got culled.
+ *
+ *	The connection is on the rxrpc_waiting_client_conns list which is kept
+ *	in to-be-granted order.  Culled conns with waiters go to the back of
+ *	the queue just like new conns.
+ *
+ *  (3) ACTIVE - The connection has at least one call in progress upon it, it
+ *      may freely grant available channels to new calls and calls may be
+ *      waiting on it for channels to become available.
+ *
+ *	The connection is on the rxrpc_active_client_conns list which is kept
+ *	in activation order for culling purposes.
+ *
+ *	rxrpc_nr_active_client_conns is held incremented also.
+ *
+ *  (4) CULLED - The connection got summarily culled to try and free up
+ *      capacity.  Calls currently in progress on the connection are allowed to
+ *      continue, but new calls will have to wait.  There can be no waiters in
+ *      this state - the conn would have to go to the WAITING state instead.
+ *
+ *  (5) IDLE - The connection has no calls in progress upon it and must have
+ *      been exposed to the world (ie. the EXPOSED flag must be set).  When it
+ *      expires, the EXPOSED flag is cleared and the connection transitions to
+ *      the INACTIVE state.
+ *
+ *	The connection is on the rxrpc_idle_client_conns list which is kept in
+ *	order of how soon they'll expire.
+ *
+ * There are flags of relevance to the cache:
+ *
+ *  (1) EXPOSED - The connection ID got exposed to the world.  If this flag is
+ *      set, an extra ref is added to the connection preventing it from being
+ *      reaped when it has no calls outstanding.  This flag is cleared and the
+ *      ref dropped when a conn is discarded from the idle list.
+ *
+ *      This allows us to move terminal call state retransmission to the
+ *      connection and to discard the call immediately we think it is done
+ *      with.  It also give us a chance to reuse the connection.
+ *
+ *  (2) DONT_REUSE - The connection should be discarded as soon as possible and
+ *      should not be reused.  This is set when an exclusive connection is used
+ *      or a call ID counter overflows.
+ *
+ * The caching state may only be changed if the cache lock is held.
+ *
+ * There are two idle client connection expiry durations.  If the total number
+ * of connections is below the reap threshold, we use the normal duration; if
+ * it's above, we use the fast duration.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -16,27 +78,50 @@
 #include <linux/timer.h>
 #include "ar-internal.h"
 
+__read_mostly unsigned int rxrpc_max_client_connections = 1000;
+__read_mostly unsigned int rxrpc_reap_client_connections = 900;
+__read_mostly unsigned int rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
+__read_mostly unsigned int rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
+
+static unsigned int rxrpc_nr_client_conns;
+static unsigned int rxrpc_nr_active_client_conns;
+static __read_mostly bool rxrpc_kill_all_client_conns;
+
+static DEFINE_SPINLOCK(rxrpc_client_conn_cache_lock);
+static DEFINE_SPINLOCK(rxrpc_client_conn_discard_mutex);
+static LIST_HEAD(rxrpc_waiting_client_conns);
+static LIST_HEAD(rxrpc_active_client_conns);
+static LIST_HEAD(rxrpc_idle_client_conns);
+
 /*
  * We use machine-unique IDs for our client connections.
  */
 DEFINE_IDR(rxrpc_client_conn_ids);
 static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
 
+static void rxrpc_cull_active_client_conns(void);
+static void rxrpc_discard_expired_client_conns(struct work_struct *);
+
+static DECLARE_DELAYED_WORK(rxrpc_client_conn_reap,
+			    rxrpc_discard_expired_client_conns);
+
+const char rxrpc_conn_cache_states[RXRPC_CONN__NR_CACHE_STATES][5] = {
+	[RXRPC_CONN_CLIENT_INACTIVE]	= "Inac",
+	[RXRPC_CONN_CLIENT_WAITING]	= "Wait",
+	[RXRPC_CONN_CLIENT_ACTIVE]	= "Actv",
+	[RXRPC_CONN_CLIENT_CULLED]	= "Cull",
+	[RXRPC_CONN_CLIENT_IDLE]	= "Idle",
+};
+
 /*
  * Get a connection ID and epoch for a client connection from the global pool.
  * The connection struct pointer is then recorded in the idr radix tree.  The
- * epoch is changed if this wraps.
- *
- * TODO: The IDR tree gets very expensive on memory if the connection IDs are
- * widely scattered throughout the number space, so we shall need to retire
- * connections that have, say, an ID more than four times the maximum number of
- * client conns away from the current allocation point to try and keep the IDs
- * concentrated.  We will also need to retire connections from an old epoch.
+ * epoch doesn't change until the client is rebooted (or, at least, unless the
+ * module is unloaded).
  */
 static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
 					  gfp_t gfp)
 {
-	u32 epoch;
 	int id;
 
 	_enter("");
@@ -44,34 +129,18 @@ static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
 	idr_preload(gfp);
 	spin_lock(&rxrpc_conn_id_lock);
 
-	epoch = rxrpc_epoch;
-
-	/* We could use idr_alloc_cyclic() here, but we really need to know
-	 * when the thing wraps so that we can advance the epoch.
-	 */
-	if (rxrpc_client_conn_ids.cur == 0)
-		rxrpc_client_conn_ids.cur = 1;
-	id = idr_alloc(&rxrpc_client_conn_ids, conn,
-		       rxrpc_client_conn_ids.cur, 0x40000000, GFP_NOWAIT);
-	if (id < 0) {
-		if (id != -ENOSPC)
-			goto error;
-		id = idr_alloc(&rxrpc_client_conn_ids, conn,
-			       1, 0x40000000, GFP_NOWAIT);
-		if (id < 0)
-			goto error;
-		epoch++;
-		rxrpc_epoch = epoch;
-	}
-	rxrpc_client_conn_ids.cur = id + 1;
+	id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
+			      1, 0x40000000, GFP_NOWAIT);
+	if (id < 0)
+		goto error;
 
 	spin_unlock(&rxrpc_conn_id_lock);
 	idr_preload_end();
 
-	conn->proto.epoch = epoch;
+	conn->proto.epoch = rxrpc_epoch;
 	conn->proto.cid = id << RXRPC_CIDSHIFT;
 	set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
-	_leave(" [CID %x:%x]", epoch, conn->proto.cid);
+	_leave(" [CID %x]", conn->proto.cid);
 	return 0;
 
 error:
@@ -114,8 +183,7 @@ void rxrpc_destroy_client_conn_ids(void)
 }
 
 /*
- * Allocate a client connection.  The caller must take care to clear any
- * padding bytes in *cp.
+ * Allocate a client connection.
  */
 static struct rxrpc_connection *
 rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
@@ -131,6 +199,10 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
 		return ERR_PTR(-ENOMEM);
 	}
 
+	atomic_set(&conn->usage, 1);
+	if (cp->exclusive)
+		__set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
+
 	conn->params		= *cp;
 	conn->out_clientflag	= RXRPC_CLIENT_INITIATED;
 	conn->state		= RXRPC_CONN_CLIENT;
@@ -148,7 +220,7 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
 		goto error_2;
 
 	write_lock(&rxrpc_connection_lock);
-	list_add_tail(&conn->link, &rxrpc_connections);
+	list_add_tail(&conn->proc_link, &rxrpc_connection_proc_list);
 	write_unlock(&rxrpc_connection_lock);
 
 	/* We steal the caller's peer ref. */
@@ -156,6 +228,9 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
 	rxrpc_get_local(conn->params.local);
 	key_get(conn->params.key);
 
+	trace_rxrpc_conn(conn, rxrpc_conn_new_client, atomic_read(&conn->usage),
+			 __builtin_return_address(0));
+	trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
 	_leave(" = %p", conn);
 	return conn;
 
@@ -170,32 +245,68 @@ error_0:
 }
 
 /*
- * find a connection for a call
- * - called in process context with IRQs enabled
+ * Determine if a connection may be reused.
  */
-int rxrpc_connect_call(struct rxrpc_call *call,
-		       struct rxrpc_conn_parameters *cp,
-		       struct sockaddr_rxrpc *srx,
-		       gfp_t gfp)
+static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
+{
+	int id_cursor, id, distance, limit;
+
+	if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
+		goto dont_reuse;
+
+	if (conn->proto.epoch != rxrpc_epoch)
+		goto mark_dont_reuse;
+
+	/* The IDR tree gets very expensive on memory if the connection IDs are
+	 * widely scattered throughout the number space, so we shall want to
+	 * kill off connections that, say, have an ID more than about four
+	 * times the maximum number of client conns away from the current
+	 * allocation point to try and keep the IDs concentrated.
+	 */
+	id_cursor = READ_ONCE(rxrpc_client_conn_ids.cur);
+	id = conn->proto.cid >> RXRPC_CIDSHIFT;
+	distance = id - id_cursor;
+	if (distance < 0)
+		distance = -distance;
+	limit = round_up(rxrpc_max_client_connections, IDR_SIZE) * 4;
+	if (distance > limit)
+		goto mark_dont_reuse;
+
+	return true;
+
+mark_dont_reuse:
+	set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
+dont_reuse:
+	return false;
+}
+
+/*
+ * Create or find a client connection to use for a call.
+ *
+ * If we return with a connection, the call will be on its waiting list.  It's
+ * left to the caller to assign a channel and wake up the call.
+ */
+static int rxrpc_get_client_conn(struct rxrpc_call *call,
+				 struct rxrpc_conn_parameters *cp,
+				 struct sockaddr_rxrpc *srx,
+				 gfp_t gfp)
 {
 	struct rxrpc_connection *conn, *candidate = NULL;
 	struct rxrpc_local *local = cp->local;
 	struct rb_node *p, **pp, *parent;
 	long diff;
-	int chan;
-
-	DECLARE_WAITQUEUE(myself, current);
+	int ret = -ENOMEM;
 
 	_enter("{%d,%lx},", call->debug_id, call->user_call_ID);
 
 	cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp);
 	if (!cp->peer)
-		return -ENOMEM;
+		goto error;
 
+	/* If the connection is not meant to be exclusive, search the available
+	 * connections to see if the connection we want to use already exists.
+	 */
 	if (!cp->exclusive) {
-		/* Search for a existing client connection unless this is going
-		 * to be a connection that's used exclusively for a single call.
-		 */
 		_debug("search 1");
 		spin_lock(&local->client_conns_lock);
 		p = local->client_conns.rb_node;
@@ -206,39 +317,56 @@ int rxrpc_connect_call(struct rxrpc_call *call,
 			diff = (cmp(peer) ?:
 				cmp(key) ?:
 				cmp(security_level));
-			if (diff < 0)
+#undef cmp
+			if (diff < 0) {
 				p = p->rb_left;
-			else if (diff > 0)
+			} else if (diff > 0) {
 				p = p->rb_right;
-			else
-				goto found_extant_conn;
+			} else {
+				if (rxrpc_may_reuse_conn(conn) &&
+				    rxrpc_get_connection_maybe(conn))
+					goto found_extant_conn;
+				/* The connection needs replacing.  It's better
+				 * to effect that when we have something to
+				 * replace it with so that we don't have to
+				 * rebalance the tree twice.
+				 */
+				break;
+			}
 		}
 		spin_unlock(&local->client_conns_lock);
 	}
 
-	/* We didn't find a connection or we want an exclusive one. */
-	_debug("get new conn");
+	/* There wasn't a connection yet or we need an exclusive connection.
+	 * We need to create a candidate and then potentially redo the search
+	 * in case we're racing with another thread also trying to connect on a
+	 * shareable connection.
+	 */
+	_debug("new conn");
 	candidate = rxrpc_alloc_client_connection(cp, gfp);
-	if (!candidate) {
-		_leave(" = -ENOMEM");
-		return -ENOMEM;
+	if (IS_ERR(candidate)) {
+		ret = PTR_ERR(candidate);
+		goto error_peer;
 	}
 
+	/* Add the call to the new connection's waiting list in case we're
+	 * going to have to wait for the connection to come live.  It's our
+	 * connection, so we want first dibs on the channel slots.  We would
+	 * normally have to take channel_lock but we do this before anyone else
+	 * can see the connection.
+	 */
+	list_add_tail(&call->chan_wait_link, &candidate->waiting_calls);
+
 	if (cp->exclusive) {
-		/* Assign the call on an exclusive connection to channel 0 and
-		 * don't add the connection to the endpoint's shareable conn
-		 * lookup tree.
-		 */
-		_debug("exclusive chan 0");
-		conn = candidate;
-		atomic_set(&conn->avail_chans, RXRPC_MAXCALLS - 1);
-		spin_lock(&conn->channel_lock);
-		chan = 0;
-		goto found_channel;
+		call->conn = candidate;
+		call->security_ix = candidate->security_ix;
+		_leave(" = 0 [exclusive %d]", candidate->debug_id);
+		return 0;
 	}
 
-	/* We need to redo the search before attempting to add a new connection
-	 * lest we race with someone else adding a conflicting instance.
+	/* Publish the new connection for userspace to find.  We need to redo
+	 * the search before doing this lest we race with someone else adding a
+	 * conflicting instance.
 	 */
 	_debug("search 2");
 	spin_lock(&local->client_conns_lock);
@@ -249,124 +377,711 @@ int rxrpc_connect_call(struct rxrpc_call *call,
 		parent = *pp;
 		conn = rb_entry(parent, struct rxrpc_connection, client_node);
 
+#define cmp(X) ((long)conn->params.X - (long)candidate->params.X)
 		diff = (cmp(peer) ?:
 			cmp(key) ?:
 			cmp(security_level));
-		if (diff < 0)
+#undef cmp
+		if (diff < 0) {
 			pp = &(*pp)->rb_left;
-		else if (diff > 0)
+		} else if (diff > 0) {
 			pp = &(*pp)->rb_right;
-		else
-			goto found_extant_conn;
+		} else {
+			if (rxrpc_may_reuse_conn(conn) &&
+			    rxrpc_get_connection_maybe(conn))
+				goto found_extant_conn;
+			/* The old connection is from an outdated epoch. */
+			_debug("replace conn");
+			clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags);
+			rb_replace_node(&conn->client_node,
+					&candidate->client_node,
+					&local->client_conns);
+			trace_rxrpc_client(conn, -1, rxrpc_client_replace);
+			goto candidate_published;
+		}
 	}
 
-	/* The second search also failed; simply add the new connection with
-	 * the new call in channel 0.  Note that we need to take the channel
-	 * lock before dropping the client conn lock.
-	 */
 	_debug("new conn");
-	set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
 	rb_link_node(&candidate->client_node, parent, pp);
 	rb_insert_color(&candidate->client_node, &local->client_conns);
-attached:
-	conn = candidate;
-	candidate = NULL;
 
-	atomic_set(&conn->avail_chans, RXRPC_MAXCALLS - 1);
-	spin_lock(&conn->channel_lock);
+candidate_published:
+	set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
+	call->conn = candidate;
+	call->security_ix = candidate->security_ix;
 	spin_unlock(&local->client_conns_lock);
-	chan = 0;
+	_leave(" = 0 [new %d]", candidate->debug_id);
+	return 0;
 
-found_channel:
-	_debug("found chan");
-	call->conn	= conn;
-	call->channel	= chan;
-	call->epoch	= conn->proto.epoch;
-	call->cid	= conn->proto.cid | chan;
-	call->call_id	= ++conn->channels[chan].call_counter;
-	conn->channels[chan].call_id = call->call_id;
-	rcu_assign_pointer(conn->channels[chan].call, call);
+	/* We come here if we found a suitable connection already in existence.
+	 * Discard any candidate we may have allocated, and try to get a
+	 * channel on this one.
+	 */
+found_extant_conn:
+	_debug("found conn");
+	spin_unlock(&local->client_conns_lock);
 
-	_net("CONNECT call %d on conn %d", call->debug_id, conn->debug_id);
+	if (candidate) {
+		trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
+		rxrpc_put_connection(candidate);
+		candidate = NULL;
+	}
 
+	spin_lock(&conn->channel_lock);
+	call->conn = conn;
+	call->security_ix = conn->security_ix;
+	list_add(&call->chan_wait_link, &conn->waiting_calls);
 	spin_unlock(&conn->channel_lock);
+	_leave(" = 0 [extant %d]", conn->debug_id);
+	return 0;
+
+error_peer:
 	rxrpc_put_peer(cp->peer);
 	cp->peer = NULL;
-	_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
-	return 0;
+error:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Activate a connection.
+ */
+static void rxrpc_activate_conn(struct rxrpc_connection *conn)
+{
+	trace_rxrpc_client(conn, -1, rxrpc_client_to_active);
+	conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
+	rxrpc_nr_active_client_conns++;
+	list_move_tail(&conn->cache_link, &rxrpc_active_client_conns);
+}
+
+/*
+ * Attempt to animate a connection for a new call.
+ *
+ * If it's not exclusive, the connection is in the endpoint tree, and we're in
+ * the conn's list of those waiting to grab a channel.  There is, however, a
+ * limit on the number of live connections allowed at any one time, so we may
+ * have to wait for capacity to become available.
+ *
+ * Note that a connection on the waiting queue might *also* have active
+ * channels if it has been culled to make space and then re-requested by a new
+ * call.
+ */
+static void rxrpc_animate_client_conn(struct rxrpc_connection *conn)
+{
+	unsigned int nr_conns;
+
+	_enter("%d,%d", conn->debug_id, conn->cache_state);
+
+	if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE)
+		goto out;
+
+	spin_lock(&rxrpc_client_conn_cache_lock);
+
+	nr_conns = rxrpc_nr_client_conns;
+	if (!test_and_set_bit(RXRPC_CONN_COUNTED, &conn->flags)) {
+		trace_rxrpc_client(conn, -1, rxrpc_client_count);
+		rxrpc_nr_client_conns = nr_conns + 1;
+	}
+
+	switch (conn->cache_state) {
+	case RXRPC_CONN_CLIENT_ACTIVE:
+	case RXRPC_CONN_CLIENT_WAITING:
+		break;
+
+	case RXRPC_CONN_CLIENT_INACTIVE:
+	case RXRPC_CONN_CLIENT_CULLED:
+	case RXRPC_CONN_CLIENT_IDLE:
+		if (nr_conns >= rxrpc_max_client_connections)
+			goto wait_for_capacity;
+		goto activate_conn;
+
+	default:
+		BUG();
+	}
+
+out_unlock:
+	spin_unlock(&rxrpc_client_conn_cache_lock);
+out:
+	_leave(" [%d]", conn->cache_state);
+	return;
+
+activate_conn:
+	_debug("activate");
+	rxrpc_activate_conn(conn);
+	goto out_unlock;
+
+wait_for_capacity:
+	_debug("wait");
+	trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting);
+	conn->cache_state = RXRPC_CONN_CLIENT_WAITING;
+	list_move_tail(&conn->cache_link, &rxrpc_waiting_client_conns);
+	goto out_unlock;
+}
+
+/*
+ * Deactivate a channel.
+ */
+static void rxrpc_deactivate_one_channel(struct rxrpc_connection *conn,
+					 unsigned int channel)
+{
+	struct rxrpc_channel *chan = &conn->channels[channel];
+
+	rcu_assign_pointer(chan->call, NULL);
+	conn->active_chans &= ~(1 << channel);
+}
+
+/*
+ * Assign a channel to the call at the front of the queue and wake the call up.
+ * We don't increment the callNumber counter until this number has been exposed
+ * to the world.
+ */
+static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
+				       unsigned int channel)
+{
+	struct rxrpc_channel *chan = &conn->channels[channel];
+	struct rxrpc_call *call = list_entry(conn->waiting_calls.next,
+					     struct rxrpc_call, chan_wait_link);
+	u32 call_id = chan->call_counter + 1;
+
+	trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
+
+	write_lock_bh(&call->state_lock);
+	call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
+	write_unlock_bh(&call->state_lock);
+
+	rxrpc_see_call(call);
+	list_del_init(&call->chan_wait_link);
+	conn->active_chans |= 1 << channel;
+	call->peer	= rxrpc_get_peer(conn->params.peer);
+	call->cid	= conn->proto.cid | channel;
+	call->call_id	= call_id;
+
+	_net("CONNECT call %08x:%08x as call %d on conn %d",
+	     call->cid, call->call_id, call->debug_id, conn->debug_id);
 
-	/* We found a potentially suitable connection already in existence.  If
-	 * we can reuse it (ie. its usage count hasn't been reduced to 0 by the
-	 * reaper), discard any candidate we may have allocated, and try to get
-	 * a channel on this one, otherwise we have to replace it.
+	/* Paired with the read barrier in rxrpc_wait_for_channel().  This
+	 * orders cid and epoch in the connection wrt to call_id without the
+	 * need to take the channel_lock.
+	 *
+	 * We provisionally assign a callNumber at this point, but we don't
+	 * confirm it until the call is about to be exposed.
+	 *
+	 * TODO: Pair with a barrier in the data_ready handler when that looks
+	 * at the call ID through a connection channel.
 	 */
-found_extant_conn:
-	_debug("found conn");
-	if (!rxrpc_get_connection_maybe(conn)) {
-		set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
-		rb_replace_node(&conn->client_node,
-				&candidate->client_node,
-				&local->client_conns);
-		clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags);
-		goto attached;
+	smp_wmb();
+	chan->call_id	= call_id;
+	rcu_assign_pointer(chan->call, call);
+	wake_up(&call->waitq);
+}
+
+/*
+ * Assign channels and callNumbers to waiting calls with channel_lock
+ * held by caller.
+ */
+static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn)
+{
+	u8 avail, mask;
+
+	switch (conn->cache_state) {
+	case RXRPC_CONN_CLIENT_ACTIVE:
+		mask = RXRPC_ACTIVE_CHANS_MASK;
+		break;
+	default:
+		return;
 	}
 
-	spin_unlock(&local->client_conns_lock);
+	while (!list_empty(&conn->waiting_calls) &&
+	       (avail = ~conn->active_chans,
+		avail &= mask,
+		avail != 0))
+		rxrpc_activate_one_channel(conn, __ffs(avail));
+}
+
+/*
+ * Assign channels and callNumbers to waiting calls.
+ */
+static void rxrpc_activate_channels(struct rxrpc_connection *conn)
+{
+	_enter("%d", conn->debug_id);
 
-	rxrpc_put_connection(candidate);
+	trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans);
+
+	if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK)
+		return;
+
+	spin_lock(&conn->channel_lock);
+	rxrpc_activate_channels_locked(conn);
+	spin_unlock(&conn->channel_lock);
+	_leave("");
+}
+
+/*
+ * Wait for a callNumber and a channel to be granted to a call.
+ */
+static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp)
+{
+	int ret = 0;
+
+	_enter("%d", call->debug_id);
+
+	if (!call->call_id) {
+		DECLARE_WAITQUEUE(myself, current);
 
-	if (!atomic_add_unless(&conn->avail_chans, -1, 0)) {
 		if (!gfpflags_allow_blocking(gfp)) {
-			rxrpc_put_connection(conn);
-			_leave(" = -EAGAIN");
-			return -EAGAIN;
+			ret = -EAGAIN;
+			goto out;
 		}
 
-		add_wait_queue(&conn->channel_wq, &myself);
+		add_wait_queue_exclusive(&call->waitq, &myself);
 		for (;;) {
 			set_current_state(TASK_INTERRUPTIBLE);
-			if (atomic_add_unless(&conn->avail_chans, -1, 0))
+			if (call->call_id)
+				break;
+			if (signal_pending(current)) {
+				ret = -ERESTARTSYS;
 				break;
-			if (signal_pending(current))
-				goto interrupted;
+			}
 			schedule();
 		}
-		remove_wait_queue(&conn->channel_wq, &myself);
+		remove_wait_queue(&call->waitq, &myself);
 		__set_current_state(TASK_RUNNING);
 	}
 
-	/* The connection allegedly now has a free channel and we can now
-	 * attach the call to it.
-	 */
+	/* Paired with the write barrier in rxrpc_activate_one_channel(). */
+	smp_rmb();
+
+out:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * find a connection for a call
+ * - called in process context with IRQs enabled
+ */
+int rxrpc_connect_call(struct rxrpc_call *call,
+		       struct rxrpc_conn_parameters *cp,
+		       struct sockaddr_rxrpc *srx,
+		       gfp_t gfp)
+{
+	int ret;
+
+	_enter("{%d,%lx},", call->debug_id, call->user_call_ID);
+
+	rxrpc_discard_expired_client_conns(NULL);
+	rxrpc_cull_active_client_conns();
+
+	ret = rxrpc_get_client_conn(call, cp, srx, gfp);
+	if (ret < 0)
+		return ret;
+
+	rxrpc_animate_client_conn(call->conn);
+	rxrpc_activate_channels(call->conn);
+
+	ret = rxrpc_wait_for_channel(call, gfp);
+	if (ret < 0)
+		rxrpc_disconnect_client_call(call);
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Note that a connection is about to be exposed to the world.  Once it is
+ * exposed, we maintain an extra ref on it that stops it from being summarily
+ * discarded before it's (a) had a chance to deal with retransmission and (b)
+ * had a chance at re-use (the per-connection security negotiation is
+ * expensive).
+ */
+static void rxrpc_expose_client_conn(struct rxrpc_connection *conn,
+				     unsigned int channel)
+{
+	if (!test_and_set_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
+		trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
+		rxrpc_get_connection(conn);
+	}
+}
+
+/*
+ * Note that a call, and thus a connection, is about to be exposed to the
+ * world.
+ */
+void rxrpc_expose_client_call(struct rxrpc_call *call)
+{
+	unsigned int channel = call->cid & RXRPC_CHANNELMASK;
+	struct rxrpc_connection *conn = call->conn;
+	struct rxrpc_channel *chan = &conn->channels[channel];
+
+	if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
+		/* Mark the call ID as being used.  If the callNumber counter
+		 * exceeds ~2 billion, we kill the connection after its
+		 * outstanding calls have finished so that the counter doesn't
+		 * wrap.
+		 */
+		chan->call_counter++;
+		if (chan->call_counter >= INT_MAX)
+			set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
+		rxrpc_expose_client_conn(conn, channel);
+	}
+}
+
+/*
+ * Disconnect a client call.
+ */
+void rxrpc_disconnect_client_call(struct rxrpc_call *call)
+{
+	unsigned int channel = call->cid & RXRPC_CHANNELMASK;
+	struct rxrpc_connection *conn = call->conn;
+	struct rxrpc_channel *chan = &conn->channels[channel];
+
+	trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
+	call->conn = NULL;
+
 	spin_lock(&conn->channel_lock);
 
-	for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
-		if (!conn->channels[chan].call)
-			goto found_channel;
-	BUG();
+	/* Calls that have never actually been assigned a channel can simply be
+	 * discarded.  If the conn didn't get used either, it will follow
+	 * immediately unless someone else grabs it in the meantime.
+	 */
+	if (!list_empty(&call->chan_wait_link)) {
+		_debug("call is waiting");
+		ASSERTCMP(call->call_id, ==, 0);
+		ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
+		list_del_init(&call->chan_wait_link);
+
+		trace_rxrpc_client(conn, channel, rxrpc_client_chan_unstarted);
+
+		/* We must deactivate or idle the connection if it's now
+		 * waiting for nothing.
+		 */
+		spin_lock(&rxrpc_client_conn_cache_lock);
+		if (conn->cache_state == RXRPC_CONN_CLIENT_WAITING &&
+		    list_empty(&conn->waiting_calls) &&
+		    !conn->active_chans)
+			goto idle_connection;
+		goto out;
+	}
+
+	ASSERTCMP(rcu_access_pointer(chan->call), ==, call);
+
+	/* If a client call was exposed to the world, we save the result for
+	 * retransmission.
+	 *
+	 * We use a barrier here so that the call number and abort code can be
+	 * read without needing to take a lock.
+	 *
+	 * TODO: Make the incoming packet handler check this and handle
+	 * terminal retransmission without requiring access to the call.
+	 */
+	if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
+		_debug("exposed %u,%u", call->call_id, call->abort_code);
+		__rxrpc_disconnect_call(conn, call);
+	}
+
+	/* See if we can pass the channel directly to another call. */
+	if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE &&
+	    !list_empty(&conn->waiting_calls)) {
+		trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
+		rxrpc_activate_one_channel(conn, channel);
+		goto out_2;
+	}
+
+	/* Things are more complex and we need the cache lock.  We might be
+	 * able to simply idle the conn or it might now be lurking on the wait
+	 * list.  It might even get moved back to the active list whilst we're
+	 * waiting for the lock.
+	 */
+	spin_lock(&rxrpc_client_conn_cache_lock);
+
+	switch (conn->cache_state) {
+	case RXRPC_CONN_CLIENT_ACTIVE:
+		if (list_empty(&conn->waiting_calls)) {
+			rxrpc_deactivate_one_channel(conn, channel);
+			if (!conn->active_chans) {
+				rxrpc_nr_active_client_conns--;
+				goto idle_connection;
+			}
+			goto out;
+		}
+
+		trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
+		rxrpc_activate_one_channel(conn, channel);
+		goto out;
 
-interrupted:
-	remove_wait_queue(&conn->channel_wq, &myself);
-	__set_current_state(TASK_RUNNING);
+	case RXRPC_CONN_CLIENT_CULLED:
+		rxrpc_deactivate_one_channel(conn, channel);
+		ASSERT(list_empty(&conn->waiting_calls));
+		if (!conn->active_chans)
+			goto idle_connection;
+		goto out;
+
+	case RXRPC_CONN_CLIENT_WAITING:
+		rxrpc_deactivate_one_channel(conn, channel);
+		goto out;
+
+	default:
+		BUG();
+	}
+
+out:
+	spin_unlock(&rxrpc_client_conn_cache_lock);
+out_2:
+	spin_unlock(&conn->channel_lock);
 	rxrpc_put_connection(conn);
-	rxrpc_put_peer(cp->peer);
-	cp->peer = NULL;
-	_leave(" = -ERESTARTSYS");
-	return -ERESTARTSYS;
+	_leave("");
+	return;
+
+idle_connection:
+	/* As no channels remain active, the connection gets deactivated
+	 * immediately or moved to the idle list for a short while.
+	 */
+	if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
+		trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
+		conn->idle_timestamp = jiffies;
+		conn->cache_state = RXRPC_CONN_CLIENT_IDLE;
+		list_move_tail(&conn->cache_link, &rxrpc_idle_client_conns);
+		if (rxrpc_idle_client_conns.next == &conn->cache_link &&
+		    !rxrpc_kill_all_client_conns)
+			queue_delayed_work(rxrpc_workqueue,
+					   &rxrpc_client_conn_reap,
+					   rxrpc_conn_idle_client_expiry);
+	} else {
+		trace_rxrpc_client(conn, channel, rxrpc_client_to_inactive);
+		conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE;
+		list_del_init(&conn->cache_link);
+	}
+	goto out;
 }
 
 /*
- * Remove a client connection from the local endpoint's tree, thereby removing
- * it as a target for reuse for new client calls.
+ * Clean up a dead client connection.
  */
-void rxrpc_unpublish_client_conn(struct rxrpc_connection *conn)
+static struct rxrpc_connection *
+rxrpc_put_one_client_conn(struct rxrpc_connection *conn)
 {
+	struct rxrpc_connection *next = NULL;
 	struct rxrpc_local *local = conn->params.local;
+	unsigned int nr_conns;
 
-	spin_lock(&local->client_conns_lock);
-	if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags))
-		rb_erase(&conn->client_node, &local->client_conns);
-	spin_unlock(&local->client_conns_lock);
+	trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
+
+	if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags)) {
+		spin_lock(&local->client_conns_lock);
+		if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS,
+				       &conn->flags))
+			rb_erase(&conn->client_node, &local->client_conns);
+		spin_unlock(&local->client_conns_lock);
+	}
 
 	rxrpc_put_client_connection_id(conn);
+
+	ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_INACTIVE);
+
+	if (test_bit(RXRPC_CONN_COUNTED, &conn->flags)) {
+		trace_rxrpc_client(conn, -1, rxrpc_client_uncount);
+		spin_lock(&rxrpc_client_conn_cache_lock);
+		nr_conns = --rxrpc_nr_client_conns;
+
+		if (nr_conns < rxrpc_max_client_connections &&
+		    !list_empty(&rxrpc_waiting_client_conns)) {
+			next = list_entry(rxrpc_waiting_client_conns.next,
+					  struct rxrpc_connection, cache_link);
+			rxrpc_get_connection(next);
+			rxrpc_activate_conn(next);
+		}
+
+		spin_unlock(&rxrpc_client_conn_cache_lock);
+	}
+
+	rxrpc_kill_connection(conn);
+	if (next)
+		rxrpc_activate_channels(next);
+
+	/* We need to get rid of the temporary ref we took upon next, but we
+	 * can't call rxrpc_put_connection() recursively.
+	 */
+	return next;
+}
+
+/*
+ * Clean up a dead client connections.
+ */
+void rxrpc_put_client_conn(struct rxrpc_connection *conn)
+{
+	const void *here = __builtin_return_address(0);
+	int n;
+
+	do {
+		n = atomic_dec_return(&conn->usage);
+		trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here);
+		if (n > 0)
+			return;
+		ASSERTCMP(n, >=, 0);
+
+		conn = rxrpc_put_one_client_conn(conn);
+	} while (conn);
+}
+
+/*
+ * Kill the longest-active client connections to make room for new ones.
+ */
+static void rxrpc_cull_active_client_conns(void)
+{
+	struct rxrpc_connection *conn;
+	unsigned int nr_conns = rxrpc_nr_client_conns;
+	unsigned int nr_active, limit;
+
+	_enter("");
+
+	ASSERTCMP(nr_conns, >=, 0);
+	if (nr_conns < rxrpc_max_client_connections) {
+		_leave(" [ok]");
+		return;
+	}
+	limit = rxrpc_reap_client_connections;
+
+	spin_lock(&rxrpc_client_conn_cache_lock);
+	nr_active = rxrpc_nr_active_client_conns;
+
+	while (nr_active > limit) {
+		ASSERT(!list_empty(&rxrpc_active_client_conns));
+		conn = list_entry(rxrpc_active_client_conns.next,
+				  struct rxrpc_connection, cache_link);
+		ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_ACTIVE);
+
+		if (list_empty(&conn->waiting_calls)) {
+			trace_rxrpc_client(conn, -1, rxrpc_client_to_culled);
+			conn->cache_state = RXRPC_CONN_CLIENT_CULLED;
+			list_del_init(&conn->cache_link);
+		} else {
+			trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting);
+			conn->cache_state = RXRPC_CONN_CLIENT_WAITING;
+			list_move_tail(&conn->cache_link,
+				       &rxrpc_waiting_client_conns);
+		}
+
+		nr_active--;
+	}
+
+	rxrpc_nr_active_client_conns = nr_active;
+	spin_unlock(&rxrpc_client_conn_cache_lock);
+	ASSERTCMP(nr_active, >=, 0);
+	_leave(" [culled]");
+}
+
+/*
+ * Discard expired client connections from the idle list.  Each conn in the
+ * idle list has been exposed and holds an extra ref because of that.
+ *
+ * This may be called from conn setup or from a work item so cannot be
+ * considered non-reentrant.
+ */
+static void rxrpc_discard_expired_client_conns(struct work_struct *work)
+{
+	struct rxrpc_connection *conn;
+	unsigned long expiry, conn_expires_at, now;
+	unsigned int nr_conns;
+	bool did_discard = false;
+
+	_enter("%c", work ? 'w' : 'n');
+
+	if (list_empty(&rxrpc_idle_client_conns)) {
+		_leave(" [empty]");
+		return;
+	}
+
+	/* Don't double up on the discarding */
+	if (!spin_trylock(&rxrpc_client_conn_discard_mutex)) {
+		_leave(" [already]");
+		return;
+	}
+
+	/* We keep an estimate of what the number of conns ought to be after
+	 * we've discarded some so that we don't overdo the discarding.
+	 */
+	nr_conns = rxrpc_nr_client_conns;
+
+next:
+	spin_lock(&rxrpc_client_conn_cache_lock);
+
+	if (list_empty(&rxrpc_idle_client_conns))
+		goto out;
+
+	conn = list_entry(rxrpc_idle_client_conns.next,
+			  struct rxrpc_connection, cache_link);
+	ASSERT(test_bit(RXRPC_CONN_EXPOSED, &conn->flags));
+
+	if (!rxrpc_kill_all_client_conns) {
+		/* If the number of connections is over the reap limit, we
+		 * expedite discard by reducing the expiry timeout.  We must,
+		 * however, have at least a short grace period to be able to do
+		 * final-ACK or ABORT retransmission.
+		 */
+		expiry = rxrpc_conn_idle_client_expiry;
+		if (nr_conns > rxrpc_reap_client_connections)
+			expiry = rxrpc_conn_idle_client_fast_expiry;
+
+		conn_expires_at = conn->idle_timestamp + expiry;
+
+		now = READ_ONCE(jiffies);
+		if (time_after(conn_expires_at, now))
+			goto not_yet_expired;
+	}
+
+	trace_rxrpc_client(conn, -1, rxrpc_client_discard);
+	if (!test_and_clear_bit(RXRPC_CONN_EXPOSED, &conn->flags))
+		BUG();
+	conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE;
+	list_del_init(&conn->cache_link);
+
+	spin_unlock(&rxrpc_client_conn_cache_lock);
+
+	/* When we cleared the EXPOSED flag, we took on responsibility for the
+	 * reference that that had on the usage count.  We deal with that here.
+	 * If someone re-sets the flag and re-gets the ref, that's fine.
+	 */
+	rxrpc_put_connection(conn);
+	did_discard = true;
+	nr_conns--;
+	goto next;
+
+not_yet_expired:
+	/* The connection at the front of the queue hasn't yet expired, so
+	 * schedule the work item for that point if we discarded something.
+	 *
+	 * We don't worry if the work item is already scheduled - it can look
+	 * after rescheduling itself at a later time.  We could cancel it, but
+	 * then things get messier.
+	 */
+	_debug("not yet");
+	if (!rxrpc_kill_all_client_conns)
+		queue_delayed_work(rxrpc_workqueue,
+				   &rxrpc_client_conn_reap,
+				   conn_expires_at - now);
+
+out:
+	spin_unlock(&rxrpc_client_conn_cache_lock);
+	spin_unlock(&rxrpc_client_conn_discard_mutex);
+	_leave("");
+}
+
+/*
+ * Preemptively destroy all the client connection records rather than waiting
+ * for them to time out
+ */
+void __exit rxrpc_destroy_all_client_connections(void)
+{
+	_enter("");
+
+	spin_lock(&rxrpc_client_conn_cache_lock);
+	rxrpc_kill_all_client_conns = true;
+	spin_unlock(&rxrpc_client_conn_cache_lock);
+
+	cancel_delayed_work(&rxrpc_client_conn_reap);
+
+	if (!queue_delayed_work(rxrpc_workqueue, &rxrpc_client_conn_reap, 0))
+		_debug("destroy: queue failed");
+
+	_leave("");
 }
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index cee0f35bc1cf..3f9d8d7ec632 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -15,20 +15,128 @@
 #include <linux/net.h>
 #include <linux/skbuff.h>
 #include <linux/errqueue.h>
-#include <linux/udp.h>
-#include <linux/in.h>
-#include <linux/in6.h>
-#include <linux/icmp.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <net/ip.h>
 #include "ar-internal.h"
 
 /*
+ * Retransmit terminal ACK or ABORT of the previous call.
+ */
+static void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
+				       struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct rxrpc_channel *chan;
+	struct msghdr msg;
+	struct kvec iov;
+	struct {
+		struct rxrpc_wire_header whdr;
+		union {
+			struct {
+				__be32 code;
+			} abort;
+			struct {
+				struct rxrpc_ackpacket ack;
+				u8 padding[3];
+				struct rxrpc_ackinfo info;
+			};
+		};
+	} __attribute__((packed)) pkt;
+	size_t len;
+	u32 serial, mtu, call_id;
+
+	_enter("%d", conn->debug_id);
+
+	chan = &conn->channels[sp->hdr.cid & RXRPC_CHANNELMASK];
+
+	/* If the last call got moved on whilst we were waiting to run, just
+	 * ignore this packet.
+	 */
+	call_id = READ_ONCE(chan->last_call);
+	/* Sync with __rxrpc_disconnect_call() */
+	smp_rmb();
+	if (call_id != sp->hdr.callNumber)
+		return;
+
+	msg.msg_name	= &conn->params.peer->srx.transport;
+	msg.msg_namelen	= conn->params.peer->srx.transport_len;
+	msg.msg_control	= NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags	= 0;
+
+	pkt.whdr.epoch		= htonl(sp->hdr.epoch);
+	pkt.whdr.cid		= htonl(sp->hdr.cid);
+	pkt.whdr.callNumber	= htonl(sp->hdr.callNumber);
+	pkt.whdr.seq		= 0;
+	pkt.whdr.type		= chan->last_type;
+	pkt.whdr.flags		= conn->out_clientflag;
+	pkt.whdr.userStatus	= 0;
+	pkt.whdr.securityIndex	= conn->security_ix;
+	pkt.whdr._rsvd		= 0;
+	pkt.whdr.serviceId	= htons(chan->last_service_id);
+
+	len = sizeof(pkt.whdr);
+	switch (chan->last_type) {
+	case RXRPC_PACKET_TYPE_ABORT:
+		pkt.abort.code	= htonl(chan->last_abort);
+		len += sizeof(pkt.abort);
+		break;
+
+	case RXRPC_PACKET_TYPE_ACK:
+		mtu = conn->params.peer->if_mtu;
+		mtu -= conn->params.peer->hdrsize;
+		pkt.ack.bufferSpace	= 0;
+		pkt.ack.maxSkew		= htons(skb->priority);
+		pkt.ack.firstPacket	= htonl(chan->last_seq);
+		pkt.ack.previousPacket	= htonl(chan->last_seq - 1);
+		pkt.ack.serial		= htonl(sp->hdr.serial);
+		pkt.ack.reason		= RXRPC_ACK_DUPLICATE;
+		pkt.ack.nAcks		= 0;
+		pkt.info.rxMTU		= htonl(rxrpc_rx_mtu);
+		pkt.info.maxMTU		= htonl(mtu);
+		pkt.info.rwind		= htonl(rxrpc_rx_window_size);
+		pkt.info.jumbo_max	= htonl(rxrpc_rx_jumbo_max);
+		pkt.whdr.flags		|= RXRPC_SLOW_START_OK;
+		len += sizeof(pkt.ack) + sizeof(pkt.info);
+		break;
+	}
+
+	/* Resync with __rxrpc_disconnect_call() and check that the last call
+	 * didn't get advanced whilst we were filling out the packets.
+	 */
+	smp_rmb();
+	if (READ_ONCE(chan->last_call) != call_id)
+		return;
+
+	iov.iov_base	= &pkt;
+	iov.iov_len	= len;
+
+	serial = atomic_inc_return(&conn->serial);
+	pkt.whdr.serial = htonl(serial);
+
+	switch (chan->last_type) {
+	case RXRPC_PACKET_TYPE_ABORT:
+		_proto("Tx ABORT %%%u { %d } [re]", serial, conn->local_abort);
+		break;
+	case RXRPC_PACKET_TYPE_ACK:
+		trace_rxrpc_tx_ack(NULL, serial, chan->last_seq, 0,
+				   RXRPC_ACK_DUPLICATE, 0);
+		_proto("Tx ACK %%%u [re]", serial);
+		break;
+	}
+
+	kernel_sendmsg(conn->params.local->socket, &msg, &iov, 1, len);
+	_leave("");
+	return;
+}
+
+/*
  * pass a connection-level abort onto all calls on that connection
  */
-static void rxrpc_abort_calls(struct rxrpc_connection *conn, int state,
-			      u32 abort_code)
+static void rxrpc_abort_calls(struct rxrpc_connection *conn,
+			      enum rxrpc_call_completion compl,
+			      u32 abort_code, int error)
 {
 	struct rxrpc_call *call;
 	int i;
@@ -41,19 +149,15 @@ static void rxrpc_abort_calls(struct rxrpc_connection *conn, int state,
 		call = rcu_dereference_protected(
 			conn->channels[i].call,
 			lockdep_is_held(&conn->channel_lock));
-		write_lock_bh(&call->state_lock);
-		if (call->state <= RXRPC_CALL_COMPLETE) {
-			call->state = state;
-			if (state == RXRPC_CALL_LOCALLY_ABORTED) {
-				call->local_abort = conn->local_abort;
-				set_bit(RXRPC_CALL_EV_CONN_ABORT, &call->events);
-			} else {
-				call->remote_abort = conn->remote_abort;
-				set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
-			}
-			rxrpc_queue_call(call);
+		if (call) {
+			if (compl == RXRPC_CALL_LOCALLY_ABORTED)
+				trace_rxrpc_abort("CON", call->cid,
+						  call->call_id, 0,
+						  abort_code, error);
+			if (rxrpc_set_call_completion(call, compl,
+						      abort_code, error))
+				rxrpc_notify_socket(call);
 		}
-		write_unlock_bh(&call->state_lock);
 	}
 
 	spin_unlock(&conn->channel_lock);
@@ -78,17 +182,16 @@ static int rxrpc_abort_connection(struct rxrpc_connection *conn,
 
 	/* generate a connection-level abort */
 	spin_lock_bh(&conn->state_lock);
-	if (conn->state < RXRPC_CONN_REMOTELY_ABORTED) {
-		conn->state = RXRPC_CONN_LOCALLY_ABORTED;
-		conn->error = error;
-		spin_unlock_bh(&conn->state_lock);
-	} else {
+	if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 		spin_unlock_bh(&conn->state_lock);
 		_leave(" = 0 [already dead]");
 		return 0;
 	}
 
-	rxrpc_abort_calls(conn, RXRPC_CALL_LOCALLY_ABORTED, abort_code);
+	conn->state = RXRPC_CONN_LOCALLY_ABORTED;
+	spin_unlock_bh(&conn->state_lock);
+
+	rxrpc_abort_calls(conn, RXRPC_CALL_LOCALLY_ABORTED, abort_code, error);
 
 	msg.msg_name	= &conn->params.peer->srx.transport;
 	msg.msg_namelen	= conn->params.peer->srx.transport_len;
@@ -132,17 +235,18 @@ static int rxrpc_abort_connection(struct rxrpc_connection *conn,
 
 /*
  * mark a call as being on a now-secured channel
- * - must be called with softirqs disabled
+ * - must be called with BH's disabled.
  */
 static void rxrpc_call_is_secure(struct rxrpc_call *call)
 {
 	_enter("%p", call);
 	if (call) {
-		read_lock(&call->state_lock);
-		if (call->state < RXRPC_CALL_COMPLETE &&
-		    !test_and_set_bit(RXRPC_CALL_EV_SECURED, &call->events))
-			rxrpc_queue_call(call);
-		read_unlock(&call->state_lock);
+		write_lock_bh(&call->state_lock);
+		if (call->state == RXRPC_CALL_SERVER_SECURING) {
+			call->state = RXRPC_CALL_SERVER_ACCEPTING;
+			rxrpc_notify_socket(call);
+		}
+		write_unlock_bh(&call->state_lock);
 	}
 }
 
@@ -159,22 +263,28 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 	int loop, ret;
 
 	if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
-		kleave(" = -ECONNABORTED [%u]", conn->state);
+		_leave(" = -ECONNABORTED [%u]", conn->state);
 		return -ECONNABORTED;
 	}
 
 	_enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
 
 	switch (sp->hdr.type) {
+	case RXRPC_PACKET_TYPE_DATA:
+	case RXRPC_PACKET_TYPE_ACK:
+		rxrpc_conn_retransmit_call(conn, skb);
+		return 0;
+
 	case RXRPC_PACKET_TYPE_ABORT:
-		if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
+		if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+				  &wtmp, sizeof(wtmp)) < 0)
 			return -EPROTO;
 		abort_code = ntohl(wtmp);
 		_proto("Rx ABORT %%%u { ac=%d }", sp->hdr.serial, abort_code);
 
 		conn->state = RXRPC_CONN_REMOTELY_ABORTED;
 		rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED,
-				  abort_code);
+				  abort_code, ECONNABORTED);
 		return -ECONNABORTED;
 
 	case RXRPC_PACKET_TYPE_CHALLENGE:
@@ -199,14 +309,16 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 
 		if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
 			conn->state = RXRPC_CONN_SERVICE;
+			spin_unlock(&conn->state_lock);
 			for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
 				rxrpc_call_is_secure(
 					rcu_dereference_protected(
 						conn->channels[loop].call,
 						lockdep_is_held(&conn->channel_lock)));
+		} else {
+			spin_unlock(&conn->state_lock);
 		}
 
-		spin_unlock(&conn->state_lock);
 		spin_unlock(&conn->channel_lock);
 		return 0;
 
@@ -269,7 +381,7 @@ void rxrpc_process_connection(struct work_struct *work)
 	u32 abort_code = RX_PROTOCOL_ERROR;
 	int ret;
 
-	_enter("{%d}", conn->debug_id);
+	rxrpc_see_connection(conn);
 
 	if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
 		rxrpc_secure_connection(conn);
@@ -277,6 +389,7 @@ void rxrpc_process_connection(struct work_struct *work)
 	/* go through the conn-level event packets, releasing the ref on this
 	 * connection that each one has when we've finished with it */
 	while ((skb = skb_dequeue(&conn->rx_queue))) {
+		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 		ret = rxrpc_process_event(conn, skb, &abort_code);
 		switch (ret) {
 		case -EPROTO:
@@ -287,7 +400,7 @@ void rxrpc_process_connection(struct work_struct *work)
 			goto requeue_and_leave;
 		case -ECONNABORTED:
 		default:
-			rxrpc_free_skb(skb);
+			rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 			break;
 		}
 	}
@@ -304,91 +417,7 @@ requeue_and_leave:
 protocol_error:
 	if (rxrpc_abort_connection(conn, -ret, abort_code) < 0)
 		goto requeue_and_leave;
-	rxrpc_free_skb(skb);
+	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 	_leave(" [EPROTO]");
 	goto out;
 }
-
-/*
- * put a packet up for transport-level abort
- */
-void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
-{
-	CHECK_SLAB_OKAY(&local->usage);
-
-	skb_queue_tail(&local->reject_queue, skb);
-	rxrpc_queue_local(local);
-}
-
-/*
- * reject packets through the local endpoint
- */
-void rxrpc_reject_packets(struct rxrpc_local *local)
-{
-	union {
-		struct sockaddr sa;
-		struct sockaddr_in sin;
-	} sa;
-	struct rxrpc_skb_priv *sp;
-	struct rxrpc_wire_header whdr;
-	struct sk_buff *skb;
-	struct msghdr msg;
-	struct kvec iov[2];
-	size_t size;
-	__be32 code;
-
-	_enter("%d", local->debug_id);
-
-	iov[0].iov_base = &whdr;
-	iov[0].iov_len = sizeof(whdr);
-	iov[1].iov_base = &code;
-	iov[1].iov_len = sizeof(code);
-	size = sizeof(whdr) + sizeof(code);
-
-	msg.msg_name = &sa;
-	msg.msg_control = NULL;
-	msg.msg_controllen = 0;
-	msg.msg_flags = 0;
-
-	memset(&sa, 0, sizeof(sa));
-	sa.sa.sa_family = local->srx.transport.family;
-	switch (sa.sa.sa_family) {
-	case AF_INET:
-		msg.msg_namelen = sizeof(sa.sin);
-		break;
-	default:
-		msg.msg_namelen = 0;
-		break;
-	}
-
-	memset(&whdr, 0, sizeof(whdr));
-	whdr.type = RXRPC_PACKET_TYPE_ABORT;
-
-	while ((skb = skb_dequeue(&local->reject_queue))) {
-		sp = rxrpc_skb(skb);
-		switch (sa.sa.sa_family) {
-		case AF_INET:
-			sa.sin.sin_port = udp_hdr(skb)->source;
-			sa.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
-			code = htonl(skb->priority);
-
-			whdr.epoch	= htonl(sp->hdr.epoch);
-			whdr.cid	= htonl(sp->hdr.cid);
-			whdr.callNumber	= htonl(sp->hdr.callNumber);
-			whdr.serviceId	= htons(sp->hdr.serviceId);
-			whdr.flags	= sp->hdr.flags;
-			whdr.flags	^= RXRPC_CLIENT_INITIATED;
-			whdr.flags	&= RXRPC_CLIENT_INITIATED;
-
-			kernel_sendmsg(local->socket, &msg, iov, 2, size);
-			break;
-
-		default:
-			break;
-		}
-
-		rxrpc_free_skb(skb);
-	}
-
-	_leave("");
-}
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 896d84493a05..e1e83af47866 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -1,6 +1,6 @@
-/* RxRPC virtual connection handler
+/* RxRPC virtual connection handler, common bits.
  *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -15,8 +15,6 @@
 #include <linux/slab.h>
 #include <linux/net.h>
 #include <linux/skbuff.h>
-#include <net/sock.h>
-#include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
 /*
@@ -27,9 +25,12 @@ unsigned int rxrpc_connection_expiry = 10 * 60;
 static void rxrpc_connection_reaper(struct work_struct *work);
 
 LIST_HEAD(rxrpc_connections);
+LIST_HEAD(rxrpc_connection_proc_list);
 DEFINE_RWLOCK(rxrpc_connection_lock);
 static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
 
+static void rxrpc_destroy_connection(struct rcu_head *);
+
 /*
  * allocate a new connection
  */
@@ -41,21 +42,18 @@ struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
 
 	conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
 	if (conn) {
+		INIT_LIST_HEAD(&conn->cache_link);
 		spin_lock_init(&conn->channel_lock);
-		init_waitqueue_head(&conn->channel_wq);
+		INIT_LIST_HEAD(&conn->waiting_calls);
 		INIT_WORK(&conn->processor, &rxrpc_process_connection);
+		INIT_LIST_HEAD(&conn->proc_link);
 		INIT_LIST_HEAD(&conn->link);
 		skb_queue_head_init(&conn->rx_queue);
 		conn->security = &rxrpc_no_security;
 		spin_lock_init(&conn->state_lock);
-		/* We maintain an extra ref on the connection whilst it is
-		 * on the rxrpc_connections list.
-		 */
-		atomic_set(&conn->usage, 2);
 		conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
-		atomic_set(&conn->avail_chans, RXRPC_MAXCALLS);
 		conn->size_align = 4;
-		conn->header_size = sizeof(struct rxrpc_wire_header);
+		conn->idle_timestamp = jiffies;
 	}
 
 	_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
@@ -135,6 +133,16 @@ struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
 			    srx.transport.sin.sin_addr.s_addr)
 				goto not_found;
 			break;
+#ifdef CONFIG_AF_RXRPC_IPV6
+		case AF_INET6:
+			if (peer->srx.transport.sin6.sin6_port !=
+			    srx.transport.sin6.sin6_port ||
+			    memcmp(&peer->srx.transport.sin6.sin6_addr,
+				   &srx.transport.sin6.sin6_addr,
+				   sizeof(struct in6_addr)) != 0)
+				goto not_found;
+			break;
+#endif
 		default:
 			BUG();
 		}
@@ -153,25 +161,32 @@ not_found:
  * terminates.  The caller must hold the channel_lock and must release the
  * call's ref on the connection.
  */
-void __rxrpc_disconnect_call(struct rxrpc_call *call)
+void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
+			     struct rxrpc_call *call)
 {
-	struct rxrpc_connection *conn = call->conn;
-	struct rxrpc_channel *chan = &conn->channels[call->channel];
+	struct rxrpc_channel *chan =
+		&conn->channels[call->cid & RXRPC_CHANNELMASK];
 
-	_enter("%d,%d", conn->debug_id, call->channel);
+	_enter("%d,%x", conn->debug_id, call->cid);
 
 	if (rcu_access_pointer(chan->call) == call) {
 		/* Save the result of the call so that we can repeat it if necessary
 		 * through the channel, whilst disposing of the actual call record.
 		 */
-		chan->last_result = call->local_abort;
+		chan->last_service_id = call->service_id;
+		if (call->abort_code) {
+			chan->last_abort = call->abort_code;
+			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
+		} else {
+			chan->last_seq = call->rx_hard_ack;
+			chan->last_type = RXRPC_PACKET_TYPE_ACK;
+		}
+		/* Sync with rxrpc_conn_retransmit(). */
 		smp_wmb();
 		chan->last_call = chan->call_id;
 		chan->call_id = chan->call_counter;
 
 		rcu_assign_pointer(chan->call, NULL);
-		atomic_inc(&conn->avail_chans);
-		wake_up(&conn->channel_wq);
 	}
 
 	_leave("");
@@ -185,34 +200,122 @@ void rxrpc_disconnect_call(struct rxrpc_call *call)
 {
 	struct rxrpc_connection *conn = call->conn;
 
+	spin_lock_bh(&conn->params.peer->lock);
+	hlist_del_init(&call->error_link);
+	spin_unlock_bh(&conn->params.peer->lock);
+
+	if (rxrpc_is_client_call(call))
+		return rxrpc_disconnect_client_call(call);
+
 	spin_lock(&conn->channel_lock);
-	__rxrpc_disconnect_call(call);
+	__rxrpc_disconnect_call(conn, call);
 	spin_unlock(&conn->channel_lock);
 
 	call->conn = NULL;
+	conn->idle_timestamp = jiffies;
 	rxrpc_put_connection(conn);
 }
 
 /*
- * release a virtual connection
+ * Kill off a connection.
  */
-void rxrpc_put_connection(struct rxrpc_connection *conn)
+void rxrpc_kill_connection(struct rxrpc_connection *conn)
 {
-	if (!conn)
-		return;
+	ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
+	       !rcu_access_pointer(conn->channels[1].call) &&
+	       !rcu_access_pointer(conn->channels[2].call) &&
+	       !rcu_access_pointer(conn->channels[3].call));
+	ASSERT(list_empty(&conn->cache_link));
 
-	_enter("%p{u=%d,d=%d}",
-	       conn, atomic_read(&conn->usage), conn->debug_id);
+	write_lock(&rxrpc_connection_lock);
+	list_del_init(&conn->proc_link);
+	write_unlock(&rxrpc_connection_lock);
 
-	ASSERTCMP(atomic_read(&conn->usage), >, 1);
+	/* Drain the Rx queue.  Note that even though we've unpublished, an
+	 * incoming packet could still be being added to our Rx queue, so we
+	 * will need to drain it again in the RCU cleanup handler.
+	 */
+	rxrpc_purge_queue(&conn->rx_queue);
 
-	conn->put_time = ktime_get_seconds();
-	if (atomic_dec_return(&conn->usage) == 1) {
-		_debug("zombie");
-		rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
+	/* Leave final destruction to RCU.  The connection processor work item
+	 * must carry a ref on the connection to prevent us getting here whilst
+	 * it is queued or running.
+	 */
+	call_rcu(&conn->rcu, rxrpc_destroy_connection);
+}
+
+/*
+ * Queue a connection's work processor, getting a ref to pass to the work
+ * queue.
+ */
+bool rxrpc_queue_conn(struct rxrpc_connection *conn)
+{
+	const void *here = __builtin_return_address(0);
+	int n = __atomic_add_unless(&conn->usage, 1, 0);
+	if (n == 0)
+		return false;
+	if (rxrpc_queue_work(&conn->processor))
+		trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
+	else
+		rxrpc_put_connection(conn);
+	return true;
+}
+
+/*
+ * Note the re-emergence of a connection.
+ */
+void rxrpc_see_connection(struct rxrpc_connection *conn)
+{
+	const void *here = __builtin_return_address(0);
+	if (conn) {
+		int n = atomic_read(&conn->usage);
+
+		trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
+	}
+}
+
+/*
+ * Get a ref on a connection.
+ */
+void rxrpc_get_connection(struct rxrpc_connection *conn)
+{
+	const void *here = __builtin_return_address(0);
+	int n = atomic_inc_return(&conn->usage);
+
+	trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
+}
+
+/*
+ * Try to get a ref on a connection.
+ */
+struct rxrpc_connection *
+rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
+{
+	const void *here = __builtin_return_address(0);
+
+	if (conn) {
+		int n = __atomic_add_unless(&conn->usage, 1, 0);
+		if (n > 0)
+			trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
+		else
+			conn = NULL;
 	}
+	return conn;
+}
 
-	_leave("");
+/*
+ * Release a service connection
+ */
+void rxrpc_put_service_conn(struct rxrpc_connection *conn)
+{
+	const void *here = __builtin_return_address(0);
+	int n;
+
+	n = atomic_dec_return(&conn->usage);
+	trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
+	ASSERTCMP(n, >=, 0);
+	if (n == 0)
+		rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 }
 
 /*
@@ -242,19 +345,19 @@ static void rxrpc_destroy_connection(struct rcu_head *rcu)
 }
 
 /*
- * reap dead connections
+ * reap dead service connections
  */
 static void rxrpc_connection_reaper(struct work_struct *work)
 {
 	struct rxrpc_connection *conn, *_p;
-	unsigned long reap_older_than, earliest, put_time, now;
+	unsigned long reap_older_than, earliest, idle_timestamp, now;
 
 	LIST_HEAD(graveyard);
 
 	_enter("");
 
-	now = ktime_get_seconds();
-	reap_older_than =  now - rxrpc_connection_expiry;
+	now = jiffies;
+	reap_older_than = now - rxrpc_connection_expiry * HZ;
 	earliest = ULONG_MAX;
 
 	write_lock(&rxrpc_connection_lock);
@@ -262,11 +365,17 @@ static void rxrpc_connection_reaper(struct work_struct *work)
 		ASSERTCMP(atomic_read(&conn->usage), >, 0);
 		if (likely(atomic_read(&conn->usage) > 1))
 			continue;
+		if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
+			continue;
+
+		idle_timestamp = READ_ONCE(conn->idle_timestamp);
+		_debug("reap CONN %d { u=%d,t=%ld }",
+		       conn->debug_id, atomic_read(&conn->usage),
+		       (long)reap_older_than - (long)idle_timestamp);
 
-		put_time = READ_ONCE(conn->put_time);
-		if (time_after(put_time, reap_older_than)) {
-			if (time_before(put_time, earliest))
-				earliest = put_time;
+		if (time_after(idle_timestamp, reap_older_than)) {
+			if (time_before(idle_timestamp, earliest))
+				earliest = idle_timestamp;
 			continue;
 		}
 
@@ -277,7 +386,7 @@ static void rxrpc_connection_reaper(struct work_struct *work)
 			continue;
 
 		if (rxrpc_conn_is_client(conn))
-			rxrpc_unpublish_client_conn(conn);
+			BUG();
 		else
 			rxrpc_unpublish_service_conn(conn);
 
@@ -287,9 +396,9 @@ static void rxrpc_connection_reaper(struct work_struct *work)
 
 	if (earliest != ULONG_MAX) {
 		_debug("reschedule reaper %ld", (long) earliest - now);
-		ASSERTCMP(earliest, >, now);
+		ASSERT(time_after(earliest, now));
 		rxrpc_queue_delayed_work(&rxrpc_connection_reap,
-					 (earliest - now) * HZ);
+					 earliest - now);
 	}
 
 	while (!list_empty(&graveyard)) {
@@ -298,16 +407,15 @@ static void rxrpc_connection_reaper(struct work_struct *work)
 		list_del_init(&conn->link);
 
 		ASSERTCMP(atomic_read(&conn->usage), ==, 0);
-		skb_queue_purge(&conn->rx_queue);
-		call_rcu(&conn->rcu, rxrpc_destroy_connection);
+		rxrpc_kill_connection(conn);
 	}
 
 	_leave("");
 }
 
 /*
- * preemptively destroy all the connection records rather than waiting for them
- * to time out
+ * preemptively destroy all the service connection records rather than
+ * waiting for them to time out
  */
 void __exit rxrpc_destroy_all_connections(void)
 {
@@ -316,6 +424,8 @@ void __exit rxrpc_destroy_all_connections(void)
 
 	_enter("");
 
+	rxrpc_destroy_all_client_connections();
+
 	rxrpc_connection_expiry = 0;
 	cancel_delayed_work(&rxrpc_connection_reap);
 	rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
@@ -330,6 +440,8 @@ void __exit rxrpc_destroy_all_connections(void)
 	write_unlock(&rxrpc_connection_lock);
 	BUG_ON(leak);
 
+	ASSERT(list_empty(&rxrpc_connection_proc_list));
+
 	/* Make sure the local and peer records pinned by any dying connections
 	 * are released.
 	 */
diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c
index fd9027ccba8f..eef551f40dc2 100644
--- a/net/rxrpc/conn_service.c
+++ b/net/rxrpc/conn_service.c
@@ -65,9 +65,8 @@ done:
  * Insert a service connection into a peer's tree, thereby making it a target
  * for incoming packets.
  */
-static struct rxrpc_connection *
-rxrpc_publish_service_conn(struct rxrpc_peer *peer,
-			   struct rxrpc_connection *conn)
+static void rxrpc_publish_service_conn(struct rxrpc_peer *peer,
+				       struct rxrpc_connection *conn)
 {
 	struct rxrpc_connection *cursor = NULL;
 	struct rxrpc_conn_proto k = conn->proto;
@@ -96,7 +95,7 @@ conn_published:
 	set_bit(RXRPC_CONN_IN_SERVICE_CONNS, &conn->flags);
 	write_sequnlock_bh(&peer->service_conn_lock);
 	_leave(" = %d [new]", conn->debug_id);
-	return conn;
+	return;
 
 found_extant_conn:
 	if (atomic_read(&cursor->usage) == 0)
@@ -119,100 +118,58 @@ replace_old_connection:
 }
 
 /*
- * get a record of an incoming connection
+ * Preallocate a service connection.  The connection is placed on the proc and
+ * reap lists so that we don't have to get the lock from BH context.
  */
-struct rxrpc_connection *rxrpc_incoming_connection(struct rxrpc_local *local,
-						   struct sockaddr_rxrpc *srx,
-						   struct sk_buff *skb)
+struct rxrpc_connection *rxrpc_prealloc_service_connection(gfp_t gfp)
 {
-	struct rxrpc_connection *conn;
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	struct rxrpc_peer *peer;
-	const char *new = "old";
-
-	_enter("");
+	struct rxrpc_connection *conn = rxrpc_alloc_connection(gfp);
 
-	peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
-	if (!peer) {
-		_debug("no peer");
-		return ERR_PTR(-EBUSY);
-	}
+	if (conn) {
+		/* We maintain an extra ref on the connection whilst it is on
+		 * the rxrpc_connections list.
+		 */
+		conn->state = RXRPC_CONN_SERVICE_PREALLOC;
+		atomic_set(&conn->usage, 2);
 
-	ASSERT(sp->hdr.flags & RXRPC_CLIENT_INITIATED);
-
-	rcu_read_lock();
-	peer = rxrpc_lookup_peer_rcu(local, srx);
-	if (peer) {
-		conn = rxrpc_find_service_conn_rcu(peer, skb);
-		if (conn) {
-			if (sp->hdr.securityIndex != conn->security_ix)
-				goto security_mismatch_rcu;
-			if (rxrpc_get_connection_maybe(conn))
-				goto found_extant_connection_rcu;
-
-			/* The conn has expired but we can't remove it without
-			 * the appropriate lock, so we attempt to replace it
-			 * when we have a new candidate.
-			 */
-		}
+		write_lock(&rxrpc_connection_lock);
+		list_add_tail(&conn->link, &rxrpc_connections);
+		list_add_tail(&conn->proc_link, &rxrpc_connection_proc_list);
+		write_unlock(&rxrpc_connection_lock);
 
-		if (!rxrpc_get_peer_maybe(peer))
-			peer = NULL;
+		trace_rxrpc_conn(conn, rxrpc_conn_new_service,
+				 atomic_read(&conn->usage),
+				 __builtin_return_address(0));
 	}
-	rcu_read_unlock();
 
-	if (!peer) {
-		peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
-		if (!peer)
-			goto enomem;
-	}
+	return conn;
+}
 
-	/* We don't have a matching record yet. */
-	conn = rxrpc_alloc_connection(GFP_NOIO);
-	if (!conn)
-		goto enomem_peer;
+/*
+ * Set up an incoming connection.  This is called in BH context with the RCU
+ * read lock held.
+ */
+void rxrpc_new_incoming_connection(struct rxrpc_connection *conn,
+				   struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+
+	_enter("");
 
 	conn->proto.epoch	= sp->hdr.epoch;
 	conn->proto.cid		= sp->hdr.cid & RXRPC_CIDMASK;
-	conn->params.local	= local;
-	conn->params.peer	= peer;
 	conn->params.service_id	= sp->hdr.serviceId;
 	conn->security_ix	= sp->hdr.securityIndex;
 	conn->out_clientflag	= 0;
-	conn->state		= RXRPC_CONN_SERVICE;
-	if (conn->params.service_id)
+	if (conn->security_ix)
 		conn->state	= RXRPC_CONN_SERVICE_UNSECURED;
-
-	rxrpc_get_local(local);
-
-	write_lock(&rxrpc_connection_lock);
-	list_add_tail(&conn->link, &rxrpc_connections);
-	write_unlock(&rxrpc_connection_lock);
+	else
+		conn->state	= RXRPC_CONN_SERVICE;
 
 	/* Make the connection a target for incoming packets. */
-	rxrpc_publish_service_conn(peer, conn);
-
-	new = "new";
-
-success:
-	_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->proto.cid);
-	_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
-	return conn;
-
-found_extant_connection_rcu:
-	rcu_read_unlock();
-	goto success;
-
-security_mismatch_rcu:
-	rcu_read_unlock();
-	_leave(" = -EKEYREJECTED");
-	return ERR_PTR(-EKEYREJECTED);
+	rxrpc_publish_service_conn(conn->params.peer, conn);
 
-enomem_peer:
-	rxrpc_put_peer(peer);
-enomem:
-	_leave(" = -ENOMEM");
-	return ERR_PTR(-ENOMEM);
+	_net("CONNECTION new %d {%x}", conn->debug_id, conn->proto.cid);
 }
 
 /*
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 70bb77818dea..3ad9f75031e3 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -1,6 +1,6 @@
 /* RxRPC packet reception
  *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -27,550 +27,920 @@
 #include <net/net_namespace.h>
 #include "ar-internal.h"
 
+static void rxrpc_proto_abort(const char *why,
+			      struct rxrpc_call *call, rxrpc_seq_t seq)
+{
+	if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, EBADMSG)) {
+		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
+		rxrpc_queue_call(call);
+	}
+}
+
 /*
- * queue a packet for recvmsg to pass to userspace
- * - the caller must hold a lock on call->lock
- * - must not be called with interrupts disabled (sk_filter() disables BH's)
- * - eats the packet whether successful or not
- * - there must be just one reference to the packet, which the caller passes to
- *   this function
+ * Do TCP-style congestion management [RFC 5681].
  */
-int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
-			bool force, bool terminal)
+static void rxrpc_congestion_management(struct rxrpc_call *call,
+					struct sk_buff *skb,
+					struct rxrpc_ack_summary *summary,
+					rxrpc_serial_t acked_serial)
 {
-	struct rxrpc_skb_priv *sp;
-	struct rxrpc_sock *rx = call->socket;
-	struct sock *sk;
-	int ret;
+	enum rxrpc_congest_change change = rxrpc_cong_no_change;
+	unsigned int cumulative_acks = call->cong_cumul_acks;
+	unsigned int cwnd = call->cong_cwnd;
+	bool resend = false;
+
+	summary->flight_size =
+		(call->tx_top - call->tx_hard_ack) - summary->nr_acks;
+
+	if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
+		summary->retrans_timeo = true;
+		call->cong_ssthresh = max_t(unsigned int,
+					    summary->flight_size / 2, 2);
+		cwnd = 1;
+		if (cwnd >= call->cong_ssthresh &&
+		    call->cong_mode == RXRPC_CALL_SLOW_START) {
+			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
+			call->cong_tstamp = skb->tstamp;
+			cumulative_acks = 0;
+		}
+	}
 
-	_enter(",,%d,%d", force, terminal);
+	cumulative_acks += summary->nr_new_acks;
+	cumulative_acks += summary->nr_rot_new_acks;
+	if (cumulative_acks > 255)
+		cumulative_acks = 255;
+
+	summary->mode = call->cong_mode;
+	summary->cwnd = call->cong_cwnd;
+	summary->ssthresh = call->cong_ssthresh;
+	summary->cumulative_acks = cumulative_acks;
+	summary->dup_acks = call->cong_dup_acks;
+
+	switch (call->cong_mode) {
+	case RXRPC_CALL_SLOW_START:
+		if (summary->nr_nacks > 0)
+			goto packet_loss_detected;
+		if (summary->cumulative_acks > 0)
+			cwnd += 1;
+		if (cwnd >= call->cong_ssthresh) {
+			call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
+			call->cong_tstamp = skb->tstamp;
+		}
+		goto out;
 
-	ASSERT(!irqs_disabled());
+	case RXRPC_CALL_CONGEST_AVOIDANCE:
+		if (summary->nr_nacks > 0)
+			goto packet_loss_detected;
 
-	sp = rxrpc_skb(skb);
-	ASSERTCMP(sp->call, ==, call);
-
-	/* if we've already posted the terminal message for a call, then we
-	 * don't post any more */
-	if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
-		_debug("already terminated");
-		ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
-		rxrpc_free_skb(skb);
-		return 0;
-	}
-
-	sk = &rx->sk;
-
-	if (!force) {
-		/* cast skb->rcvbuf to unsigned...  It's pointless, but
-		 * reduces number of warnings when compiling with -W
-		 * --ANK */
-//		ret = -ENOBUFS;
-//		if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
-//		    (unsigned int) sk->sk_rcvbuf)
-//			goto out;
-
-		ret = sk_filter(sk, skb);
-		if (ret < 0)
+		/* We analyse the number of packets that get ACK'd per RTT
+		 * period and increase the window if we managed to fill it.
+		 */
+		if (call->peer->rtt_usage == 0)
 			goto out;
-	}
+		if (ktime_before(skb->tstamp,
+				 ktime_add_ns(call->cong_tstamp,
+					      call->peer->rtt)))
+			goto out_no_clear_ca;
+		change = rxrpc_cong_rtt_window_end;
+		call->cong_tstamp = skb->tstamp;
+		if (cumulative_acks >= cwnd)
+			cwnd++;
+		goto out;
 
-	spin_lock_bh(&sk->sk_receive_queue.lock);
-	if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
-	    !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    call->socket->sk.sk_state != RXRPC_CLOSE) {
-		skb->destructor = rxrpc_packet_destructor;
-		skb->dev = NULL;
-		skb->sk = sk;
-		atomic_add(skb->truesize, &sk->sk_rmem_alloc);
+	case RXRPC_CALL_PACKET_LOSS:
+		if (summary->nr_nacks == 0)
+			goto resume_normality;
 
-		if (terminal) {
-			_debug("<<<< TERMINAL MESSAGE >>>>");
-			set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
+		if (summary->new_low_nack) {
+			change = rxrpc_cong_new_low_nack;
+			call->cong_dup_acks = 1;
+			if (call->cong_extra > 1)
+				call->cong_extra = 1;
+			goto send_extra_data;
 		}
 
-		/* allow interception by a kernel service */
-		if (rx->interceptor) {
-			rx->interceptor(sk, call->user_call_ID, skb);
-			spin_unlock_bh(&sk->sk_receive_queue.lock);
-		} else {
-			_net("post skb %p", skb);
-			__skb_queue_tail(&sk->sk_receive_queue, skb);
-			spin_unlock_bh(&sk->sk_receive_queue.lock);
+		call->cong_dup_acks++;
+		if (call->cong_dup_acks < 3)
+			goto send_extra_data;
+
+		change = rxrpc_cong_begin_retransmission;
+		call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
+		call->cong_ssthresh = max_t(unsigned int,
+					    summary->flight_size / 2, 2);
+		cwnd = call->cong_ssthresh + 3;
+		call->cong_extra = 0;
+		call->cong_dup_acks = 0;
+		resend = true;
+		goto out;
 
-			if (!sock_flag(sk, SOCK_DEAD))
-				sk->sk_data_ready(sk);
+	case RXRPC_CALL_FAST_RETRANSMIT:
+		if (!summary->new_low_nack) {
+			if (summary->nr_new_acks == 0)
+				cwnd += 1;
+			call->cong_dup_acks++;
+			if (call->cong_dup_acks == 2) {
+				change = rxrpc_cong_retransmit_again;
+				call->cong_dup_acks = 0;
+				resend = true;
+			}
+		} else {
+			change = rxrpc_cong_progress;
+			cwnd = call->cong_ssthresh;
+			if (summary->nr_nacks == 0)
+				goto resume_normality;
 		}
-		skb = NULL;
-	} else {
-		spin_unlock_bh(&sk->sk_receive_queue.lock);
+		goto out;
+
+	default:
+		BUG();
+		goto out;
 	}
-	ret = 0;
 
+resume_normality:
+	change = rxrpc_cong_cleared_nacks;
+	call->cong_dup_acks = 0;
+	call->cong_extra = 0;
+	call->cong_tstamp = skb->tstamp;
+	if (cwnd < call->cong_ssthresh)
+		call->cong_mode = RXRPC_CALL_SLOW_START;
+	else
+		call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 out:
-	rxrpc_free_skb(skb);
+	cumulative_acks = 0;
+out_no_clear_ca:
+	if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
+		cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
+	call->cong_cwnd = cwnd;
+	call->cong_cumul_acks = cumulative_acks;
+	trace_rxrpc_congest(call, summary, acked_serial, change);
+	if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
+		rxrpc_queue_call(call);
+	return;
 
-	_leave(" = %d", ret);
-	return ret;
+packet_loss_detected:
+	change = rxrpc_cong_saw_nack;
+	call->cong_mode = RXRPC_CALL_PACKET_LOSS;
+	call->cong_dup_acks = 0;
+	goto send_extra_data;
+
+send_extra_data:
+	/* Send some previously unsent DATA if we have some to advance the ACK
+	 * state.
+	 */
+	if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
+	    RXRPC_TX_ANNO_LAST ||
+	    summary->nr_acks != call->tx_top - call->tx_hard_ack) {
+		call->cong_extra++;
+		wake_up(&call->waitq);
+	}
+	goto out_no_clear_ca;
 }
 
 /*
- * process a DATA packet, posting the packet to the appropriate queue
- * - eats the packet if successful
+ * Ping the other end to fill our RTT cache and to retrieve the rwind
+ * and MTU parameters.
  */
-static int rxrpc_fast_process_data(struct rxrpc_call *call,
-				   struct sk_buff *skb, u32 seq)
+static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
+			    int skew)
 {
-	struct rxrpc_skb_priv *sp;
-	bool terminal;
-	int ret, ackbit, ack;
-	u32 serial;
-	u8 flags;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	ktime_t now = skb->tstamp;
 
-	_enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
+	if (call->peer->rtt_usage < 3 ||
+	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
+		rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
+				  true, true,
+				  rxrpc_propose_ack_ping_for_params);
+}
 
-	sp = rxrpc_skb(skb);
-	ASSERTCMP(sp->call, ==, NULL);
-	flags = sp->hdr.flags;
-	serial = sp->hdr.serial;
+/*
+ * Apply a hard ACK by advancing the Tx window.
+ */
+static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
+				   struct rxrpc_ack_summary *summary)
+{
+	struct sk_buff *skb, *list = NULL;
+	int ix;
+	u8 annotation;
+
+	if (call->acks_lowest_nak == call->tx_hard_ack) {
+		call->acks_lowest_nak = to;
+	} else if (before_eq(call->acks_lowest_nak, to)) {
+		summary->new_low_nack = true;
+		call->acks_lowest_nak = to;
+	}
 
 	spin_lock(&call->lock);
 
-	if (call->state > RXRPC_CALL_COMPLETE)
-		goto discard;
+	while (before(call->tx_hard_ack, to)) {
+		call->tx_hard_ack++;
+		ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
+		skb = call->rxtx_buffer[ix];
+		annotation = call->rxtx_annotations[ix];
+		rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
+		call->rxtx_buffer[ix] = NULL;
+		call->rxtx_annotations[ix] = 0;
+		skb->next = list;
+		list = skb;
+
+		if (annotation & RXRPC_TX_ANNO_LAST)
+			set_bit(RXRPC_CALL_TX_LAST, &call->flags);
+		if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
+			summary->nr_rot_new_acks++;
+	}
 
-	ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
-	ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
-	ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
+	spin_unlock(&call->lock);
 
-	if (seq < call->rx_data_post) {
-		_debug("dup #%u [-%u]", seq, call->rx_data_post);
-		ack = RXRPC_ACK_DUPLICATE;
-		ret = -ENOBUFS;
-		goto discard_and_ack;
-	}
+	trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
+				    rxrpc_transmit_rotate_last :
+				    rxrpc_transmit_rotate));
+	wake_up(&call->waitq);
 
-	/* we may already have the packet in the out of sequence queue */
-	ackbit = seq - (call->rx_data_eaten + 1);
-	ASSERTCMP(ackbit, >=, 0);
-	if (__test_and_set_bit(ackbit, call->ackr_window)) {
-		_debug("dup oos #%u [%u,%u]",
-		       seq, call->rx_data_eaten, call->rx_data_post);
-		ack = RXRPC_ACK_DUPLICATE;
-		goto discard_and_ack;
+	while (list) {
+		skb = list;
+		list = skb->next;
+		skb->next = NULL;
+		rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 	}
+}
 
-	if (seq >= call->ackr_win_top) {
-		_debug("exceed #%u [%u]", seq, call->ackr_win_top);
-		__clear_bit(ackbit, call->ackr_window);
-		ack = RXRPC_ACK_EXCEEDS_WINDOW;
-		goto discard_and_ack;
-	}
+/*
+ * End the transmission phase of a call.
+ *
+ * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
+ * or a final ACK packet.
+ */
+static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
+			       const char *abort_why)
+{
 
-	if (seq == call->rx_data_expect) {
-		clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
-		call->rx_data_expect++;
-	} else if (seq > call->rx_data_expect) {
-		_debug("oos #%u [%u]", seq, call->rx_data_expect);
-		call->rx_data_expect = seq + 1;
-		if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
-			ack = RXRPC_ACK_OUT_OF_SEQUENCE;
-			goto enqueue_and_ack;
-		}
-		goto enqueue_packet;
-	}
+	ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 
-	if (seq != call->rx_data_post) {
-		_debug("ahead #%u [%u]", seq, call->rx_data_post);
-		goto enqueue_packet;
-	}
+	write_lock(&call->state_lock);
 
-	if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
-		goto protocol_error;
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_SEND_REQUEST:
+	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
+		if (reply_begun)
+			call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
+		else
+			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
+		break;
 
-	/* if the packet need security things doing to it, then it goes down
-	 * the slow path */
-	if (call->conn->security_ix)
-		goto enqueue_packet;
+	case RXRPC_CALL_SERVER_AWAIT_ACK:
+		__rxrpc_call_completed(call);
+		rxrpc_notify_socket(call);
+		break;
 
-	sp->call = call;
-	rxrpc_get_call(call);
-	atomic_inc(&call->skb_count);
-	terminal = ((flags & RXRPC_LAST_PACKET) &&
-		    !(flags & RXRPC_CLIENT_INITIATED));
-	ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
-	if (ret < 0) {
-		if (ret == -ENOMEM || ret == -ENOBUFS) {
-			__clear_bit(ackbit, call->ackr_window);
-			ack = RXRPC_ACK_NOSPACE;
-			goto discard_and_ack;
-		}
-		goto out;
+	default:
+		goto bad_state;
 	}
 
-	skb = NULL;
-	sp = NULL;
-
-	_debug("post #%u", seq);
-	ASSERTCMP(call->rx_data_post, ==, seq);
-	call->rx_data_post++;
+	write_unlock(&call->state_lock);
+	if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
+		rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, false, true,
+				  rxrpc_propose_ack_client_tx_end);
+		trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
+	} else {
+		trace_rxrpc_transmit(call, rxrpc_transmit_end);
+	}
+	_leave(" = ok");
+	return true;
+
+bad_state:
+	write_unlock(&call->state_lock);
+	kdebug("end_tx %s", rxrpc_call_states[call->state]);
+	rxrpc_proto_abort(abort_why, call, call->tx_top);
+	return false;
+}
 
-	if (flags & RXRPC_LAST_PACKET)
-		set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
+/*
+ * Begin the reply reception phase of a call.
+ */
+static bool rxrpc_receiving_reply(struct rxrpc_call *call)
+{
+	struct rxrpc_ack_summary summary = { 0 };
+	rxrpc_seq_t top = READ_ONCE(call->tx_top);
+
+	if (call->ackr_reason) {
+		spin_lock_bh(&call->lock);
+		call->ackr_reason = 0;
+		call->resend_at = call->expire_at;
+		call->ack_at = call->expire_at;
+		spin_unlock_bh(&call->lock);
+		rxrpc_set_timer(call, rxrpc_timer_init_for_reply,
+				ktime_get_real());
+	}
 
-	/* if we've reached an out of sequence packet then we need to drain
-	 * that queue into the socket Rx queue now */
-	if (call->rx_data_post == call->rx_first_oos) {
-		_debug("drain rx oos now");
-		read_lock(&call->state_lock);
-		if (call->state < RXRPC_CALL_COMPLETE &&
-		    !test_and_set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events))
-			rxrpc_queue_call(call);
-		read_unlock(&call->state_lock);
+	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
+		rxrpc_rotate_tx_window(call, top, &summary);
+	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
+		rxrpc_proto_abort("TXL", call, top);
+		return false;
 	}
+	if (!rxrpc_end_tx_phase(call, true, "ETD"))
+		return false;
+	call->tx_phase = false;
+	return true;
+}
 
-	spin_unlock(&call->lock);
-	atomic_inc(&call->ackr_not_idle);
-	rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial, false);
-	_leave(" = 0 [posted]");
-	return 0;
+/*
+ * Scan a jumbo packet to validate its structure and to work out how many
+ * subpackets it contains.
+ *
+ * A jumbo packet is a collection of consecutive packets glued together with
+ * little headers between that indicate how to change the initial header for
+ * each subpacket.
+ *
+ * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
+ * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
+ * size.
+ */
+static bool rxrpc_validate_jumbo(struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	unsigned int offset = sizeof(struct rxrpc_wire_header);
+	unsigned int len = skb->len;
+	int nr_jumbo = 1;
+	u8 flags = sp->hdr.flags;
 
-protocol_error:
-	ret = -EBADMSG;
-out:
-	spin_unlock(&call->lock);
-	_leave(" = %d", ret);
-	return ret;
+	do {
+		nr_jumbo++;
+		if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
+			goto protocol_error;
+		if (flags & RXRPC_LAST_PACKET)
+			goto protocol_error;
+		offset += RXRPC_JUMBO_DATALEN;
+		if (skb_copy_bits(skb, offset, &flags, 1) < 0)
+			goto protocol_error;
+		offset += sizeof(struct rxrpc_jumbo_header);
+	} while (flags & RXRPC_JUMBO_PACKET);
 
-discard_and_ack:
-	_debug("discard and ACK packet %p", skb);
-	__rxrpc_propose_ACK(call, ack, serial, true);
-discard:
-	spin_unlock(&call->lock);
-	rxrpc_free_skb(skb);
-	_leave(" = 0 [discarded]");
-	return 0;
+	sp->nr_jumbo = nr_jumbo;
+	return true;
 
-enqueue_and_ack:
-	__rxrpc_propose_ACK(call, ack, serial, true);
-enqueue_packet:
-	_net("defer skb %p", skb);
-	spin_unlock(&call->lock);
-	skb_queue_tail(&call->rx_queue, skb);
-	atomic_inc(&call->ackr_not_idle);
-	read_lock(&call->state_lock);
-	if (call->state < RXRPC_CALL_DEAD)
-		rxrpc_queue_call(call);
-	read_unlock(&call->state_lock);
-	_leave(" = 0 [queued]");
-	return 0;
+protocol_error:
+	return false;
 }
 
 /*
- * assume an implicit ACKALL of the transmission phase of a client socket upon
- * reception of the first reply packet
+ * Handle reception of a duplicate packet.
+ *
+ * We have to take care to avoid an attack here whereby we're given a series of
+ * jumbograms, each with a sequence number one before the preceding one and
+ * filled up to maximum UDP size.  If they never send us the first packet in
+ * the sequence, they can cause us to have to hold on to around 2MiB of kernel
+ * space until the call times out.
+ *
+ * We limit the space usage by only accepting three duplicate jumbo packets per
+ * call.  After that, we tell the other side we're no longer accepting jumbos
+ * (that information is encoded in the ACK packet).
  */
-static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
+static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
+				 u8 annotation, bool *_jumbo_bad)
 {
-	write_lock_bh(&call->state_lock);
-
-	switch (call->state) {
-	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
-		call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
-		call->acks_latest = serial;
-
-		_debug("implicit ACKALL %%%u", call->acks_latest);
-		set_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events);
-		write_unlock_bh(&call->state_lock);
-
-		if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
-			clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
-			clear_bit(RXRPC_CALL_EV_RESEND, &call->events);
-			clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-		}
-		break;
+	/* Discard normal packets that are duplicates. */
+	if (annotation == 0)
+		return;
 
-	default:
-		write_unlock_bh(&call->state_lock);
-		break;
+	/* Skip jumbo subpackets that are duplicates.  When we've had three or
+	 * more partially duplicate jumbo packets, we refuse to take any more
+	 * jumbos for this call.
+	 */
+	if (!*_jumbo_bad) {
+		call->nr_jumbo_bad++;
+		*_jumbo_bad = true;
 	}
 }
 
 /*
- * post an incoming packet to the nominated call to deal with
- * - must get rid of the sk_buff, either by freeing it or by queuing it
+ * Process a DATA packet, adding the packet to the Rx ring.
  */
-void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
+static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
+			     u16 skew)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	__be32 wtmp;
-	u32 hi_serial, abort_code;
+	unsigned int offset = sizeof(struct rxrpc_wire_header);
+	unsigned int ix;
+	rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
+	rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
+	bool immediate_ack = false, jumbo_bad = false, queued;
+	u16 len;
+	u8 ack = 0, flags, annotation = 0;
 
-	_enter("%p,%p", call, skb);
+	_enter("{%u,%u},{%u,%u}",
+	       call->rx_hard_ack, call->rx_top, skb->len, seq);
 
-	ASSERT(!irqs_disabled());
+	_proto("Rx DATA %%%u { #%u f=%02x }",
+	       sp->hdr.serial, seq, sp->hdr.flags);
 
-#if 0 // INJECT RX ERROR
-	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
-		static int skip = 0;
-		if (++skip == 3) {
-			printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
-			skip = 0;
-			goto free_packet;
-		}
+	if (call->state >= RXRPC_CALL_COMPLETE)
+		return;
+
+	/* Received data implicitly ACKs all of the request packets we sent
+	 * when we're acting as a client.
+	 */
+	if ((call->state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
+	     call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
+	    !rxrpc_receiving_reply(call))
+		return;
+
+	call->ackr_prev_seq = seq;
+
+	hard_ack = READ_ONCE(call->rx_hard_ack);
+	if (after(seq, hard_ack + call->rx_winsize)) {
+		ack = RXRPC_ACK_EXCEEDS_WINDOW;
+		ack_serial = serial;
+		goto ack;
 	}
-#endif
 
-	/* track the latest serial number on this connection for ACK packet
-	 * information */
-	hi_serial = atomic_read(&call->conn->hi_serial);
-	while (sp->hdr.serial > hi_serial)
-		hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
-					   sp->hdr.serial);
+	flags = sp->hdr.flags;
+	if (flags & RXRPC_JUMBO_PACKET) {
+		if (call->nr_jumbo_bad > 3) {
+			ack = RXRPC_ACK_NOSPACE;
+			ack_serial = serial;
+			goto ack;
+		}
+		annotation = 1;
+	}
 
-	/* request ACK generation for any ACK or DATA packet that requests
-	 * it */
-	if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
-		_proto("ACK Requested on %%%u", sp->hdr.serial);
-		rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
+next_subpacket:
+	queued = false;
+	ix = seq & RXRPC_RXTX_BUFF_MASK;
+	len = skb->len;
+	if (flags & RXRPC_JUMBO_PACKET)
+		len = RXRPC_JUMBO_DATALEN;
+
+	if (flags & RXRPC_LAST_PACKET) {
+		if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
+		    seq != call->rx_top)
+			return rxrpc_proto_abort("LSN", call, seq);
+	} else {
+		if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
+		    after_eq(seq, call->rx_top))
+			return rxrpc_proto_abort("LSA", call, seq);
 	}
 
-	switch (sp->hdr.type) {
-	case RXRPC_PACKET_TYPE_ABORT:
-		_debug("abort");
+	if (before_eq(seq, hard_ack)) {
+		ack = RXRPC_ACK_DUPLICATE;
+		ack_serial = serial;
+		goto skip;
+	}
 
-		if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
-			goto protocol_error;
+	if (flags & RXRPC_REQUEST_ACK && !ack) {
+		ack = RXRPC_ACK_REQUESTED;
+		ack_serial = serial;
+	}
 
-		abort_code = ntohl(wtmp);
-		_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
-
-		write_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_COMPLETE) {
-			call->state = RXRPC_CALL_REMOTELY_ABORTED;
-			call->remote_abort = abort_code;
-			set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
-			rxrpc_queue_call(call);
+	if (call->rxtx_buffer[ix]) {
+		rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
+		if (ack != RXRPC_ACK_DUPLICATE) {
+			ack = RXRPC_ACK_DUPLICATE;
+			ack_serial = serial;
 		}
-		goto free_packet_unlock;
+		immediate_ack = true;
+		goto skip;
+	}
 
-	case RXRPC_PACKET_TYPE_BUSY:
-		_proto("Rx BUSY %%%u", sp->hdr.serial);
+	/* Queue the packet.  We use a couple of memory barriers here as need
+	 * to make sure that rx_top is perceived to be set after the buffer
+	 * pointer and that the buffer pointer is set after the annotation and
+	 * the skb data.
+	 *
+	 * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
+	 * and also rxrpc_fill_out_ack().
+	 */
+	rxrpc_get_skb(skb, rxrpc_skb_rx_got);
+	call->rxtx_annotations[ix] = annotation;
+	smp_wmb();
+	call->rxtx_buffer[ix] = skb;
+	if (after(seq, call->rx_top)) {
+		smp_store_release(&call->rx_top, seq);
+	} else if (before(seq, call->rx_top)) {
+		/* Send an immediate ACK if we fill in a hole */
+		if (!ack) {
+			ack = RXRPC_ACK_DELAY;
+			ack_serial = serial;
+		}
+		immediate_ack = true;
+	}
+	if (flags & RXRPC_LAST_PACKET) {
+		set_bit(RXRPC_CALL_RX_LAST, &call->flags);
+		trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
+	} else {
+		trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
+	}
+	queued = true;
 
-		if (rxrpc_conn_is_service(call->conn))
-			goto protocol_error;
+	if (after_eq(seq, call->rx_expect_next)) {
+		if (after(seq, call->rx_expect_next)) {
+			_net("OOS %u > %u", seq, call->rx_expect_next);
+			ack = RXRPC_ACK_OUT_OF_SEQUENCE;
+			ack_serial = serial;
+		}
+		call->rx_expect_next = seq + 1;
+	}
 
-		write_lock_bh(&call->state_lock);
-		switch (call->state) {
-		case RXRPC_CALL_CLIENT_SEND_REQUEST:
-			call->state = RXRPC_CALL_SERVER_BUSY;
-			set_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
-			rxrpc_queue_call(call);
-		case RXRPC_CALL_SERVER_BUSY:
-			goto free_packet_unlock;
-		default:
-			goto protocol_error_locked;
+skip:
+	offset += len;
+	if (flags & RXRPC_JUMBO_PACKET) {
+		if (skb_copy_bits(skb, offset, &flags, 1) < 0)
+			return rxrpc_proto_abort("XJF", call, seq);
+		offset += sizeof(struct rxrpc_jumbo_header);
+		seq++;
+		serial++;
+		annotation++;
+		if (flags & RXRPC_JUMBO_PACKET)
+			annotation |= RXRPC_RX_ANNO_JLAST;
+		if (after(seq, hard_ack + call->rx_winsize)) {
+			ack = RXRPC_ACK_EXCEEDS_WINDOW;
+			ack_serial = serial;
+			if (!jumbo_bad) {
+				call->nr_jumbo_bad++;
+				jumbo_bad = true;
+			}
+			goto ack;
 		}
 
-	default:
-		_proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
-		goto protocol_error;
+		_proto("Rx DATA Jumbo %%%u", serial);
+		goto next_subpacket;
+	}
 
-	case RXRPC_PACKET_TYPE_DATA:
-		_proto("Rx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
+	if (queued && flags & RXRPC_LAST_PACKET && !ack) {
+		ack = RXRPC_ACK_DELAY;
+		ack_serial = serial;
+	}
 
-		if (sp->hdr.seq == 0)
-			goto protocol_error;
+ack:
+	if (ack)
+		rxrpc_propose_ACK(call, ack, skew, ack_serial,
+				  immediate_ack, true,
+				  rxrpc_propose_ack_input_data);
 
-		call->ackr_prev_seq = sp->hdr.seq;
+	if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
+		rxrpc_notify_socket(call);
+	_leave(" [queued]");
+}
 
-		/* received data implicitly ACKs all of the request packets we
-		 * sent when we're acting as a client */
-		if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
-			rxrpc_assume_implicit_ackall(call, sp->hdr.serial);
+/*
+ * Process a requested ACK.
+ */
+static void rxrpc_input_requested_ack(struct rxrpc_call *call,
+				      ktime_t resp_time,
+				      rxrpc_serial_t orig_serial,
+				      rxrpc_serial_t ack_serial)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	ktime_t sent_at;
+	int ix;
+
+	for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
+		skb = call->rxtx_buffer[ix];
+		if (!skb)
+			continue;
+
+		sp = rxrpc_skb(skb);
+		if (sp->hdr.serial != orig_serial)
+			continue;
+		smp_rmb();
+		sent_at = skb->tstamp;
+		goto found;
+	}
+	return;
 
-		switch (rxrpc_fast_process_data(call, skb, sp->hdr.seq)) {
-		case 0:
-			skb = NULL;
-			goto done;
+found:
+	rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
+			   orig_serial, ack_serial, sent_at, resp_time);
+}
 
-		default:
-			BUG();
+/*
+ * Process a ping response.
+ */
+static void rxrpc_input_ping_response(struct rxrpc_call *call,
+				      ktime_t resp_time,
+				      rxrpc_serial_t orig_serial,
+				      rxrpc_serial_t ack_serial)
+{
+	rxrpc_serial_t ping_serial;
+	ktime_t ping_time;
 
-			/* data packet received beyond the last packet */
-		case -EBADMSG:
-			goto protocol_error;
-		}
+	ping_time = call->ackr_ping_time;
+	smp_rmb();
+	ping_serial = call->ackr_ping;
 
-	case RXRPC_PACKET_TYPE_ACKALL:
-	case RXRPC_PACKET_TYPE_ACK:
-		/* ACK processing is done in process context */
-		read_lock_bh(&call->state_lock);
-		if (call->state < RXRPC_CALL_DEAD) {
-			skb_queue_tail(&call->rx_queue, skb);
-			rxrpc_queue_call(call);
-			skb = NULL;
-		}
-		read_unlock_bh(&call->state_lock);
-		goto free_packet;
+	if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
+	    before(orig_serial, ping_serial))
+		return;
+	clear_bit(RXRPC_CALL_PINGING, &call->flags);
+	if (after(orig_serial, ping_serial))
+		return;
+
+	rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
+			   orig_serial, ack_serial, ping_time, resp_time);
+}
+
+/*
+ * Process the extra information that may be appended to an ACK packet
+ */
+static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
+				struct rxrpc_ackinfo *ackinfo)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct rxrpc_peer *peer;
+	unsigned int mtu;
+	u32 rwind = ntohl(ackinfo->rwind);
+
+	_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
+	       sp->hdr.serial,
+	       ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
+	       rwind, ntohl(ackinfo->jumbo_max));
+
+	if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
+		rwind = RXRPC_RXTX_BUFF_SIZE - 1;
+	call->tx_winsize = rwind;
+	if (call->cong_ssthresh > rwind)
+		call->cong_ssthresh = rwind;
+
+	mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
+
+	peer = call->peer;
+	if (mtu < peer->maxdata) {
+		spin_lock_bh(&peer->lock);
+		peer->maxdata = mtu;
+		peer->mtu = mtu + peer->hdrsize;
+		spin_unlock_bh(&peer->lock);
+		_net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 	}
+}
 
-protocol_error:
-	_debug("protocol error");
-	write_lock_bh(&call->state_lock);
-protocol_error_locked:
-	if (call->state <= RXRPC_CALL_COMPLETE) {
-		call->state = RXRPC_CALL_LOCALLY_ABORTED;
-		call->local_abort = RX_PROTOCOL_ERROR;
-		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-		rxrpc_queue_call(call);
+/*
+ * Process individual soft ACKs.
+ *
+ * Each ACK in the array corresponds to one packet and can be either an ACK or
+ * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
+ * packets that lie beyond the end of the ACK list are scheduled for resend by
+ * the timer on the basis that the peer might just not have processed them at
+ * the time the ACK was sent.
+ */
+static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
+				  rxrpc_seq_t seq, int nr_acks,
+				  struct rxrpc_ack_summary *summary)
+{
+	int ix;
+	u8 annotation, anno_type;
+
+	for (; nr_acks > 0; nr_acks--, seq++) {
+		ix = seq & RXRPC_RXTX_BUFF_MASK;
+		annotation = call->rxtx_annotations[ix];
+		anno_type = annotation & RXRPC_TX_ANNO_MASK;
+		annotation &= ~RXRPC_TX_ANNO_MASK;
+		switch (*acks++) {
+		case RXRPC_ACK_TYPE_ACK:
+			summary->nr_acks++;
+			if (anno_type == RXRPC_TX_ANNO_ACK)
+				continue;
+			summary->nr_new_acks++;
+			call->rxtx_annotations[ix] =
+				RXRPC_TX_ANNO_ACK | annotation;
+			break;
+		case RXRPC_ACK_TYPE_NACK:
+			if (!summary->nr_nacks &&
+			    call->acks_lowest_nak != seq) {
+				call->acks_lowest_nak = seq;
+				summary->new_low_nack = true;
+			}
+			summary->nr_nacks++;
+			if (anno_type == RXRPC_TX_ANNO_NAK)
+				continue;
+			summary->nr_new_nacks++;
+			if (anno_type == RXRPC_TX_ANNO_RETRANS)
+				continue;
+			call->rxtx_annotations[ix] =
+				RXRPC_TX_ANNO_NAK | annotation;
+			break;
+		default:
+			return rxrpc_proto_abort("SFT", call, 0);
+		}
 	}
-free_packet_unlock:
-	write_unlock_bh(&call->state_lock);
-free_packet:
-	rxrpc_free_skb(skb);
-done:
-	_leave("");
 }
 
 /*
- * split up a jumbo data packet
+ * Process an ACK packet.
+ *
+ * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
+ * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
+ *
+ * A hard-ACK means that a packet has been processed and may be discarded; a
+ * soft-ACK means that the packet may be discarded and retransmission
+ * requested.  A phase is complete when all packets are hard-ACK'd.
  */
-static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
-				       struct sk_buff *jumbo)
+static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
+			    u16 skew)
 {
-	struct rxrpc_jumbo_header jhdr;
-	struct rxrpc_skb_priv *sp;
-	struct sk_buff *part;
+	struct rxrpc_ack_summary summary = { 0 };
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	union {
+		struct rxrpc_ackpacket ack;
+		struct rxrpc_ackinfo info;
+		u8 acks[RXRPC_MAXACKS];
+	} buf;
+	rxrpc_serial_t acked_serial;
+	rxrpc_seq_t first_soft_ack, hard_ack;
+	int nr_acks, offset, ioffset;
+
+	_enter("");
+
+	offset = sizeof(struct rxrpc_wire_header);
+	if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
+		_debug("extraction failure");
+		return rxrpc_proto_abort("XAK", call, 0);
+	}
+	offset += sizeof(buf.ack);
+
+	acked_serial = ntohl(buf.ack.serial);
+	first_soft_ack = ntohl(buf.ack.firstPacket);
+	hard_ack = first_soft_ack - 1;
+	nr_acks = buf.ack.nAcks;
+	summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
+			      buf.ack.reason : RXRPC_ACK__INVALID);
+
+	trace_rxrpc_rx_ack(call, first_soft_ack, summary.ack_reason, nr_acks);
+
+	_proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
+	       sp->hdr.serial,
+	       ntohs(buf.ack.maxSkew),
+	       first_soft_ack,
+	       ntohl(buf.ack.previousPacket),
+	       acked_serial,
+	       rxrpc_ack_names[summary.ack_reason],
+	       buf.ack.nAcks);
+
+	if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
+		rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
+					  sp->hdr.serial);
+	if (buf.ack.reason == RXRPC_ACK_REQUESTED)
+		rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
+					  sp->hdr.serial);
+
+	if (buf.ack.reason == RXRPC_ACK_PING) {
+		_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
+		rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
+				  skew, sp->hdr.serial, true, true,
+				  rxrpc_propose_ack_respond_to_ping);
+	} else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
+		rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
+				  skew, sp->hdr.serial, true, true,
+				  rxrpc_propose_ack_respond_to_ack);
+	}
 
-	_enter(",{%u,%u}", jumbo->data_len, jumbo->len);
+	ioffset = offset + nr_acks + 3;
+	if (skb->len >= ioffset + sizeof(buf.info)) {
+		if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
+			return rxrpc_proto_abort("XAI", call, 0);
+		rxrpc_input_ackinfo(call, skb, &buf.info);
+	}
 
-	sp = rxrpc_skb(jumbo);
+	if (first_soft_ack == 0)
+		return rxrpc_proto_abort("AK0", call, 0);
 
-	do {
-		sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
-
-		/* make a clone to represent the first subpacket in what's left
-		 * of the jumbo packet */
-		part = skb_clone(jumbo, GFP_ATOMIC);
-		if (!part) {
-			/* simply ditch the tail in the event of ENOMEM */
-			pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
-			break;
-		}
-		rxrpc_new_skb(part);
+	/* Ignore ACKs unless we are or have just been transmitting. */
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_SEND_REQUEST:
+	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
+	case RXRPC_CALL_SERVER_SEND_REPLY:
+	case RXRPC_CALL_SERVER_AWAIT_ACK:
+		break;
+	default:
+		return;
+	}
 
-		pskb_trim(part, RXRPC_JUMBO_DATALEN);
+	/* Discard any out-of-order or duplicate ACKs. */
+	if (before_eq(sp->hdr.serial, call->acks_latest)) {
+		_debug("discard ACK %d <= %d",
+		       sp->hdr.serial, call->acks_latest);
+		return;
+	}
+	call->acks_latest_ts = skb->tstamp;
+	call->acks_latest = sp->hdr.serial;
+
+	if (before(hard_ack, call->tx_hard_ack) ||
+	    after(hard_ack, call->tx_top))
+		return rxrpc_proto_abort("AKW", call, 0);
+	if (nr_acks > call->tx_top - hard_ack)
+		return rxrpc_proto_abort("AKN", call, 0);
+
+	if (after(hard_ack, call->tx_hard_ack))
+		rxrpc_rotate_tx_window(call, hard_ack, &summary);
+
+	if (nr_acks > 0) {
+		if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
+			return rxrpc_proto_abort("XSA", call, 0);
+		rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
+				      &summary);
+	}
 
-		if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
-			goto protocol_error;
+	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
+		rxrpc_end_tx_phase(call, false, "ETA");
+		return;
+	}
 
-		if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
-			goto protocol_error;
-		if (!pskb_pull(jumbo, sizeof(jhdr)))
-			BUG();
+	if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
+	    RXRPC_TX_ANNO_LAST &&
+	    summary.nr_acks == call->tx_top - hard_ack)
+		rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
+				  false, true,
+				  rxrpc_propose_ack_ping_for_lost_reply);
 
-		sp->hdr.seq	+= 1;
-		sp->hdr.serial	+= 1;
-		sp->hdr.flags	= jhdr.flags;
-		sp->hdr._rsvd	= ntohs(jhdr._rsvd);
+	return rxrpc_congestion_management(call, skb, &summary, acked_serial);
+}
 
-		_proto("Rx DATA Jumbo %%%u", sp->hdr.serial - 1);
+/*
+ * Process an ACKALL packet.
+ */
+static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
+{
+	struct rxrpc_ack_summary summary = { 0 };
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 
-		rxrpc_fast_process_packet(call, part);
-		part = NULL;
+	_proto("Rx ACKALL %%%u", sp->hdr.serial);
 
-	} while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
+	rxrpc_rotate_tx_window(call, call->tx_top, &summary);
+	if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
+		rxrpc_end_tx_phase(call, false, "ETL");
+}
 
-	rxrpc_fast_process_packet(call, jumbo);
-	_leave("");
-	return;
+/*
+ * Process an ABORT packet.
+ */
+static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	__be32 wtmp;
+	u32 abort_code = RX_CALL_DEAD;
 
-protocol_error:
-	_debug("protocol error");
-	rxrpc_free_skb(part);
-	rxrpc_free_skb(jumbo);
-	write_lock_bh(&call->state_lock);
-	if (call->state <= RXRPC_CALL_COMPLETE) {
-		call->state = RXRPC_CALL_LOCALLY_ABORTED;
-		call->local_abort = RX_PROTOCOL_ERROR;
-		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-		rxrpc_queue_call(call);
-	}
-	write_unlock_bh(&call->state_lock);
-	_leave("");
+	_enter("");
+
+	if (skb->len >= 4 &&
+	    skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+			  &wtmp, sizeof(wtmp)) >= 0)
+		abort_code = ntohl(wtmp);
+
+	_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
+
+	if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
+				      abort_code, ECONNABORTED))
+		rxrpc_notify_socket(call);
 }
 
 /*
- * post an incoming packet to the appropriate call/socket to deal with
- * - must get rid of the sk_buff, either by freeing it or by queuing it
+ * Process an incoming call packet.
  */
-static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
-				      struct sk_buff *skb)
+static void rxrpc_input_call_packet(struct rxrpc_call *call,
+				    struct sk_buff *skb, u16 skew)
 {
-	struct rxrpc_skb_priv *sp;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 
 	_enter("%p,%p", call, skb);
 
-	sp = rxrpc_skb(skb);
+	switch (sp->hdr.type) {
+	case RXRPC_PACKET_TYPE_DATA:
+		rxrpc_input_data(call, skb, skew);
+		break;
 
-	_debug("extant call [%d]", call->state);
+	case RXRPC_PACKET_TYPE_ACK:
+		rxrpc_input_ack(call, skb, skew);
+		break;
+
+	case RXRPC_PACKET_TYPE_BUSY:
+		_proto("Rx BUSY %%%u", sp->hdr.serial);
+
+		/* Just ignore BUSY packets from the server; the retry and
+		 * lifespan timers will take care of business.  BUSY packets
+		 * from the client don't make sense.
+		 */
+		break;
+
+	case RXRPC_PACKET_TYPE_ABORT:
+		rxrpc_input_abort(call, skb);
+		break;
+
+	case RXRPC_PACKET_TYPE_ACKALL:
+		rxrpc_input_ackall(call, skb);
+		break;
 
-	read_lock(&call->state_lock);
-	switch (call->state) {
-	case RXRPC_CALL_LOCALLY_ABORTED:
-		if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
-			rxrpc_queue_call(call);
-			goto free_unlock;
-		}
-	case RXRPC_CALL_REMOTELY_ABORTED:
-	case RXRPC_CALL_NETWORK_ERROR:
-	case RXRPC_CALL_DEAD:
-		goto dead_call;
-	case RXRPC_CALL_COMPLETE:
-	case RXRPC_CALL_CLIENT_FINAL_ACK:
-		/* complete server call */
-		if (rxrpc_conn_is_service(call->conn))
-			goto dead_call;
-		/* resend last packet of a completed call */
-		_debug("final ack again");
-		rxrpc_get_call(call);
-		set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
-		rxrpc_queue_call(call);
-		goto free_unlock;
 	default:
+		_proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 		break;
 	}
 
-	read_unlock(&call->state_lock);
-	rxrpc_get_call(call);
-
-	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
-	    sp->hdr.flags & RXRPC_JUMBO_PACKET)
-		rxrpc_process_jumbo_packet(call, skb);
-	else
-		rxrpc_fast_process_packet(call, skb);
-
-	rxrpc_put_call(call);
-	goto done;
-
-dead_call:
-	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
-		skb->priority = RX_CALL_DEAD;
-		rxrpc_reject_packet(call->conn->params.local, skb);
-		goto unlock;
-	}
-free_unlock:
-	rxrpc_free_skb(skb);
-unlock:
-	read_unlock(&call->state_lock);
-done:
 	_leave("");
 }
 
 /*
  * post connection-level events to the connection
- * - this includes challenges, responses and some aborts
+ * - this includes challenges, responses, some aborts and call terminal packet
+ *   retransmission.
  */
 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 				      struct sk_buff *skb)
@@ -595,6 +965,17 @@ static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 }
 
 /*
+ * put a packet up for transport-level abort
+ */
+static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
+{
+	CHECK_SLAB_OKAY(&local->usage);
+
+	skb_queue_tail(&local->reject_queue, skb);
+	rxrpc_queue_local(local);
+}
+
+/*
  * Extract the wire header from a packet and translate the byte order.
  */
 static noinline
@@ -605,8 +986,6 @@ int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 	/* dig out the RxRPC connection details */
 	if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 		return -EBADMSG;
-	if (!pskb_pull(skb, sizeof(whdr)))
-		BUG();
 
 	memset(sp, 0, sizeof(*sp));
 	sp->hdr.epoch		= ntohl(whdr.epoch);
@@ -631,19 +1010,22 @@ int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
  * shut down and the local endpoint from going away, thus sk_user_data will not
  * be cleared until this function returns.
  */
-void rxrpc_data_ready(struct sock *sk)
+void rxrpc_data_ready(struct sock *udp_sk)
 {
 	struct rxrpc_connection *conn;
+	struct rxrpc_channel *chan;
+	struct rxrpc_call *call;
 	struct rxrpc_skb_priv *sp;
-	struct rxrpc_local *local = sk->sk_user_data;
+	struct rxrpc_local *local = udp_sk->sk_user_data;
 	struct sk_buff *skb;
-	int ret;
+	unsigned int channel;
+	int ret, skew;
 
-	_enter("%p", sk);
+	_enter("%p", udp_sk);
 
 	ASSERT(!irqs_disabled());
 
-	skb = skb_recv_datagram(sk, 0, 1, &ret);
+	skb = skb_recv_datagram(udp_sk, 0, 1, &ret);
 	if (!skb) {
 		if (ret == -EAGAIN)
 			return;
@@ -651,13 +1033,13 @@ void rxrpc_data_ready(struct sock *sk)
 		return;
 	}
 
-	rxrpc_new_skb(skb);
+	rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 
 	_net("recv skb %p", skb);
 
 	/* we'll probably need to checksum it (didn't call sock_recvmsg) */
 	if (skb_checksum_complete(skb)) {
-		rxrpc_free_skb(skb);
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		__UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 		_leave(" [CSUM failed]");
 		return;
@@ -671,13 +1053,21 @@ void rxrpc_data_ready(struct sock *sk)
 	skb_orphan(skb);
 	sp = rxrpc_skb(skb);
 
-	_net("Rx UDP packet from %08x:%04hu",
-	     ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
-
 	/* dig out the RxRPC connection details */
 	if (rxrpc_extract_header(sp, skb) < 0)
 		goto bad_message;
 
+	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
+		static int lose;
+		if ((lose++ & 7) == 7) {
+			trace_rxrpc_rx_lose(sp);
+			rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
+			return;
+		}
+	}
+
+	trace_rxrpc_rx_packet(sp);
+
 	_net("Rx RxRPC %s ep=%x call=%x:%x",
 	     sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 	     sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
@@ -688,70 +1078,125 @@ void rxrpc_data_ready(struct sock *sk)
 		goto bad_message;
 	}
 
-	if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
+	switch (sp->hdr.type) {
+	case RXRPC_PACKET_TYPE_VERSION:
 		rxrpc_post_packet_to_local(local, skb);
 		goto out;
-	}
 
-	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
-	    (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
-		goto bad_message;
+	case RXRPC_PACKET_TYPE_BUSY:
+		if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
+			goto discard;
+
+	case RXRPC_PACKET_TYPE_DATA:
+		if (sp->hdr.callNumber == 0)
+			goto bad_message;
+		if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
+		    !rxrpc_validate_jumbo(skb))
+			goto bad_message;
+		break;
+	}
 
 	rcu_read_lock();
 
 	conn = rxrpc_find_connection_rcu(local, skb);
-	if (!conn)
-		goto cant_route_call;
+	if (conn) {
+		if (sp->hdr.securityIndex != conn->security_ix)
+			goto wrong_security;
+
+		if (sp->hdr.callNumber == 0) {
+			/* Connection-level packet */
+			_debug("CONN %p {%d}", conn, conn->debug_id);
+			rxrpc_post_packet_to_conn(conn, skb);
+			goto out_unlock;
+		}
+
+		/* Note the serial number skew here */
+		skew = (int)sp->hdr.serial - (int)conn->hi_serial;
+		if (skew >= 0) {
+			if (skew > 0)
+				conn->hi_serial = sp->hdr.serial;
+		} else {
+			skew = -skew;
+			skew = min(skew, 65535);
+		}
 
-	if (sp->hdr.callNumber == 0) {
-		/* Connection-level packet */
-		_debug("CONN %p {%d}", conn, conn->debug_id);
-		rxrpc_post_packet_to_conn(conn, skb);
-	} else {
 		/* Call-bound packets are routed by connection channel. */
-		unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
-		struct rxrpc_channel *chan = &conn->channels[channel];
-		struct rxrpc_call *call = rcu_dereference(chan->call);
+		channel = sp->hdr.cid & RXRPC_CHANNELMASK;
+		chan = &conn->channels[channel];
+
+		/* Ignore really old calls */
+		if (sp->hdr.callNumber < chan->last_call)
+			goto discard_unlock;
+
+		if (sp->hdr.callNumber == chan->last_call) {
+			/* For the previous service call, if completed successfully, we
+			 * discard all further packets.
+			 */
+			if (rxrpc_conn_is_service(conn) &&
+			    (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
+			     sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
+				goto discard_unlock;
+
+			/* But otherwise we need to retransmit the final packet from
+			 * data cached in the connection record.
+			 */
+			rxrpc_post_packet_to_conn(conn, skb);
+			goto out_unlock;
+		}
 
-		if (!call || atomic_read(&call->usage) == 0)
-			goto cant_route_call;
+		call = rcu_dereference(chan->call);
+	} else {
+		skew = 0;
+		call = NULL;
+	}
 
-		rxrpc_post_packet_to_call(call, skb);
+	if (!call || atomic_read(&call->usage) == 0) {
+		if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
+		    sp->hdr.callNumber == 0 ||
+		    sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
+			goto bad_message_unlock;
+		if (sp->hdr.seq != 1)
+			goto discard_unlock;
+		call = rxrpc_new_incoming_call(local, conn, skb);
+		if (!call) {
+			rcu_read_unlock();
+			goto reject_packet;
+		}
+		rxrpc_send_ping(call, skb, skew);
 	}
 
+	rxrpc_input_call_packet(call, skb, skew);
+	goto discard_unlock;
+
+discard_unlock:
 	rcu_read_unlock();
+discard:
+	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 out:
+	trace_rxrpc_rx_done(0, 0);
 	return;
 
-cant_route_call:
+out_unlock:
 	rcu_read_unlock();
+	goto out;
 
-	_debug("can't route call");
-	if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
-	    sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
-		if (sp->hdr.seq == 1) {
-			_debug("first packet");
-			skb_queue_tail(&local->accept_queue, skb);
-			rxrpc_queue_work(&local->processor);
-			_leave(" [incoming]");
-			return;
-		}
-		skb->priority = RX_INVALID_OPERATION;
-	} else {
-		skb->priority = RX_CALL_DEAD;
-	}
-
-	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
-		_debug("reject type %d",sp->hdr.type);
-		rxrpc_reject_packet(local, skb);
-	} else {
-		rxrpc_free_skb(skb);
-	}
-	_leave(" [no call]");
-	return;
+wrong_security:
+	rcu_read_unlock();
+	trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+			  RXKADINCONSISTENCY, EBADMSG);
+	skb->priority = RXKADINCONSISTENCY;
+	goto post_abort;
 
+bad_message_unlock:
+	rcu_read_unlock();
 bad_message:
+	trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+			  RX_PROTOCOL_ERROR, EBADMSG);
 	skb->priority = RX_PROTOCOL_ERROR;
+post_abort:
+	skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
+reject_packet:
+	trace_rxrpc_rx_done(skb->mark, skb->priority);
 	rxrpc_reject_packet(local, skb);
 	_leave(" [badmsg]");
 }
diff --git a/net/rxrpc/insecure.c b/net/rxrpc/insecure.c
index c21ad213b337..7d4375e557e6 100644
--- a/net/rxrpc/insecure.c
+++ b/net/rxrpc/insecure.c
@@ -23,31 +23,36 @@ static int none_prime_packet_security(struct rxrpc_connection *conn)
 }
 
 static int none_secure_packet(struct rxrpc_call *call,
-			       struct sk_buff *skb,
-			       size_t data_size,
-			       void *sechdr)
+			      struct sk_buff *skb,
+			      size_t data_size,
+			      void *sechdr)
 {
 	return 0;
 }
 
-static int none_verify_packet(struct rxrpc_call *call,
-			       struct sk_buff *skb,
-			       u32 *_abort_code)
+static int none_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			      unsigned int offset, unsigned int len,
+			      rxrpc_seq_t seq, u16 expected_cksum)
 {
 	return 0;
 }
 
+static void none_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
+			     unsigned int *_offset, unsigned int *_len)
+{
+}
+
 static int none_respond_to_challenge(struct rxrpc_connection *conn,
-				      struct sk_buff *skb,
-				      u32 *_abort_code)
+				     struct sk_buff *skb,
+				     u32 *_abort_code)
 {
 	*_abort_code = RX_PROTOCOL_ERROR;
 	return -EPROTO;
 }
 
 static int none_verify_response(struct rxrpc_connection *conn,
-				 struct sk_buff *skb,
-				 u32 *_abort_code)
+				struct sk_buff *skb,
+				u32 *_abort_code)
 {
 	*_abort_code = RX_PROTOCOL_ERROR;
 	return -EPROTO;
@@ -78,6 +83,7 @@ const struct rxrpc_security rxrpc_no_security = {
 	.prime_packet_security		= none_prime_packet_security,
 	.secure_packet			= none_secure_packet,
 	.verify_packet			= none_verify_packet,
+	.locate_data			= none_locate_data,
 	.respond_to_challenge		= none_respond_to_challenge,
 	.verify_response		= none_verify_response,
 	.clear				= none_clear,
diff --git a/net/rxrpc/local_event.c b/net/rxrpc/local_event.c
index 31a3f86ef2f6..540d3955c1bc 100644
--- a/net/rxrpc/local_event.c
+++ b/net/rxrpc/local_event.c
@@ -15,8 +15,6 @@
 #include <linux/net.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
-#include <linux/udp.h>
-#include <linux/ip.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <generated/utsrelease.h>
@@ -33,7 +31,7 @@ static void rxrpc_send_version_request(struct rxrpc_local *local,
 {
 	struct rxrpc_wire_header whdr;
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	struct sockaddr_in sin;
+	struct sockaddr_rxrpc srx;
 	struct msghdr msg;
 	struct kvec iov[2];
 	size_t len;
@@ -41,12 +39,11 @@ static void rxrpc_send_version_request(struct rxrpc_local *local,
 
 	_enter("");
 
-	sin.sin_family = AF_INET;
-	sin.sin_port = udp_hdr(skb)->source;
-	sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
+	if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
+		return;
 
-	msg.msg_name	= &sin;
-	msg.msg_namelen	= sizeof(sin);
+	msg.msg_name	= &srx.transport;
+	msg.msg_namelen	= srx.transport_len;
 	msg.msg_control	= NULL;
 	msg.msg_controllen = 0;
 	msg.msg_flags	= 0;
@@ -93,11 +90,13 @@ void rxrpc_process_local_events(struct rxrpc_local *local)
 	if (skb) {
 		struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 
+		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 		_debug("{%d},{%u}", local->debug_id, sp->hdr.type);
 
 		switch (sp->hdr.type) {
 		case RXRPC_PACKET_TYPE_VERSION:
-			if (skb_copy_bits(skb, 0, &v, 1) < 0)
+			if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+					  &v, 1) < 0)
 				return;
 			_proto("Rx VERSION { %02x }", v);
 			if (v == 0)
@@ -109,7 +108,7 @@ void rxrpc_process_local_events(struct rxrpc_local *local)
 			break;
 		}
 
-		rxrpc_free_skb(skb);
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 	}
 
 	_leave("");
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index a753796fbe8f..ff4864d550b8 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -58,6 +58,17 @@ static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
 			memcmp(&local->srx.transport.sin.sin_addr,
 			       &srx->transport.sin.sin_addr,
 			       sizeof(struct in_addr));
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		/* If the choice of UDP6 port is left up to the transport, then
+		 * the endpoint record doesn't match.
+		 */
+		return ((u16 __force)local->srx.transport.sin6.sin6_port -
+			(u16 __force)srx->transport.sin6.sin6_port) ?:
+			memcmp(&local->srx.transport.sin6.sin6_addr,
+			       &srx->transport.sin6.sin6_addr,
+			       sizeof(struct in6_addr));
+#endif
 	default:
 		BUG();
 	}
@@ -75,9 +86,7 @@ static struct rxrpc_local *rxrpc_alloc_local(const struct sockaddr_rxrpc *srx)
 		atomic_set(&local->usage, 1);
 		INIT_LIST_HEAD(&local->link);
 		INIT_WORK(&local->processor, rxrpc_local_processor);
-		INIT_LIST_HEAD(&local->services);
 		init_rwsem(&local->defrag_sem);
-		skb_queue_head_init(&local->accept_queue);
 		skb_queue_head_init(&local->reject_queue);
 		skb_queue_head_init(&local->event_queue);
 		local->client_conns = RB_ROOT;
@@ -101,11 +110,12 @@ static int rxrpc_open_socket(struct rxrpc_local *local)
 	struct sock *sock;
 	int ret, opt;
 
-	_enter("%p{%d}", local, local->srx.transport_type);
+	_enter("%p{%d,%d}",
+	       local, local->srx.transport_type, local->srx.transport.family);
 
 	/* create a socket to represent the local endpoint */
-	ret = sock_create_kern(&init_net, PF_INET, local->srx.transport_type,
-			       IPPROTO_UDP, &local->socket);
+	ret = sock_create_kern(&init_net, local->srx.transport.family,
+			       local->srx.transport_type, 0, &local->socket);
 	if (ret < 0) {
 		_leave(" = %d [socket]", ret);
 		return ret;
@@ -170,18 +180,8 @@ struct rxrpc_local *rxrpc_lookup_local(const struct sockaddr_rxrpc *srx)
 	long diff;
 	int ret;
 
-	if (srx->transport.family == AF_INET) {
-		_enter("{%d,%u,%pI4+%hu}",
-		       srx->transport_type,
-		       srx->transport.family,
-		       &srx->transport.sin.sin_addr,
-		       ntohs(srx->transport.sin.sin_port));
-	} else {
-		_enter("{%d,%u}",
-		       srx->transport_type,
-		       srx->transport.family);
-		return ERR_PTR(-EAFNOSUPPORT);
-	}
+	_enter("{%d,%d,%pISp}",
+	       srx->transport_type, srx->transport.family, &srx->transport);
 
 	mutex_lock(&rxrpc_local_mutex);
 
@@ -234,13 +234,8 @@ struct rxrpc_local *rxrpc_lookup_local(const struct sockaddr_rxrpc *srx)
 found:
 	mutex_unlock(&rxrpc_local_mutex);
 
-	_net("LOCAL %s %d {%d,%u,%pI4+%hu}",
-	     age,
-	     local->debug_id,
-	     local->srx.transport_type,
-	     local->srx.transport.family,
-	     &local->srx.transport.sin.sin_addr,
-	     ntohs(local->srx.transport.sin.sin_port));
+	_net("LOCAL %s %d {%pISp}",
+	     age, local->debug_id, &local->srx.transport);
 
 	_leave(" = %p", local);
 	return local;
@@ -296,7 +291,7 @@ static void rxrpc_local_destroyer(struct rxrpc_local *local)
 	mutex_unlock(&rxrpc_local_mutex);
 
 	ASSERT(RB_EMPTY_ROOT(&local->client_conns));
-	ASSERT(list_empty(&local->services));
+	ASSERT(!local->service);
 
 	if (socket) {
 		local->socket = NULL;
@@ -308,7 +303,6 @@ static void rxrpc_local_destroyer(struct rxrpc_local *local)
 	/* At this point, there should be no more packets coming in to the
 	 * local endpoint.
 	 */
-	rxrpc_purge_queue(&local->accept_queue);
 	rxrpc_purge_queue(&local->reject_queue);
 	rxrpc_purge_queue(&local->event_queue);
 
@@ -332,11 +326,6 @@ static void rxrpc_local_processor(struct work_struct *work)
 		if (atomic_read(&local->usage) == 0)
 			return rxrpc_local_destroyer(local);
 
-		if (!skb_queue_empty(&local->accept_queue)) {
-			rxrpc_accept_incoming_calls(local);
-			again = true;
-		}
-
 		if (!skb_queue_empty(&local->reject_queue)) {
 			rxrpc_reject_packets(local);
 			again = true;
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index bdc5e42fe600..9d1c721bc4e8 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -21,28 +21,33 @@
 unsigned int rxrpc_max_backlog __read_mostly = 10;
 
 /*
+ * Maximum lifetime of a call (in mx).
+ */
+unsigned int rxrpc_max_call_lifetime = 60 * 1000;
+
+/*
  * How long to wait before scheduling ACK generation after seeing a
- * packet with RXRPC_REQUEST_ACK set (in jiffies).
+ * packet with RXRPC_REQUEST_ACK set (in ms).
  */
 unsigned int rxrpc_requested_ack_delay = 1;
 
 /*
- * How long to wait before scheduling an ACK with subtype DELAY (in jiffies).
+ * How long to wait before scheduling an ACK with subtype DELAY (in ms).
  *
  * We use this when we've received new data packets.  If those packets aren't
  * all consumed within this time we will send a DELAY ACK if an ACK was not
  * requested to let the sender know it doesn't need to resend.
  */
-unsigned int rxrpc_soft_ack_delay = 1 * HZ;
+unsigned int rxrpc_soft_ack_delay = 1 * 1000;
 
 /*
- * How long to wait before scheduling an ACK with subtype IDLE (in jiffies).
+ * How long to wait before scheduling an ACK with subtype IDLE (in ms).
  *
  * We use this when we've consumed some previously soft-ACK'd packets when
  * further packets aren't immediately received to decide when to send an IDLE
  * ACK let the other end know that it can free up its Tx buffer space.
  */
-unsigned int rxrpc_idle_ack_delay = 0.5 * HZ;
+unsigned int rxrpc_idle_ack_delay = 0.5 * 1000;
 
 /*
  * Receive window size in packets.  This indicates the maximum number of
@@ -50,7 +55,10 @@ unsigned int rxrpc_idle_ack_delay = 0.5 * HZ;
  * limit is hit, we should generate an EXCEEDS_WINDOW ACK and discard further
  * packets.
  */
-unsigned int rxrpc_rx_window_size = 32;
+unsigned int rxrpc_rx_window_size = RXRPC_INIT_RX_WINDOW_SIZE;
+#if (RXRPC_RXTX_BUFF_SIZE - 1) < RXRPC_INIT_RX_WINDOW_SIZE
+#error Need to reduce RXRPC_INIT_RX_WINDOW_SIZE
+#endif
 
 /*
  * Maximum Rx MTU size.  This indicates to the sender the size of jumbo packet
@@ -64,6 +72,11 @@ unsigned int rxrpc_rx_mtu = 5692;
  */
 unsigned int rxrpc_rx_jumbo_max = 4;
 
+/*
+ * Time till packet resend (in milliseconds).
+ */
+unsigned int rxrpc_resend_timeout = 4 * 1000;
+
 const char *const rxrpc_pkts[] = {
 	"?00",
 	"DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
@@ -75,21 +88,152 @@ const s8 rxrpc_ack_priority[] = {
 	[RXRPC_ACK_DELAY]		= 1,
 	[RXRPC_ACK_REQUESTED]		= 2,
 	[RXRPC_ACK_IDLE]		= 3,
-	[RXRPC_ACK_PING_RESPONSE]	= 4,
-	[RXRPC_ACK_DUPLICATE]		= 5,
-	[RXRPC_ACK_OUT_OF_SEQUENCE]	= 6,
-	[RXRPC_ACK_EXCEEDS_WINDOW]	= 7,
-	[RXRPC_ACK_NOSPACE]		= 8,
-};
-
-const char *rxrpc_acks(u8 reason)
-{
-	static const char *const str[] = {
-		"---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
-		"IDL", "-?-"
-	};
-
-	if (reason >= ARRAY_SIZE(str))
-		reason = ARRAY_SIZE(str) - 1;
-	return str[reason];
-}
+	[RXRPC_ACK_DUPLICATE]		= 4,
+	[RXRPC_ACK_OUT_OF_SEQUENCE]	= 5,
+	[RXRPC_ACK_EXCEEDS_WINDOW]	= 6,
+	[RXRPC_ACK_NOSPACE]		= 7,
+	[RXRPC_ACK_PING_RESPONSE]	= 8,
+	[RXRPC_ACK_PING]		= 9,
+};
+
+const char const rxrpc_ack_names[RXRPC_ACK__INVALID + 1][4] = {
+	"---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
+	"IDL", "-?-"
+};
+
+const char rxrpc_skb_traces[rxrpc_skb__nr_trace][7] = {
+	[rxrpc_skb_rx_cleaned]		= "Rx CLN",
+	[rxrpc_skb_rx_freed]		= "Rx FRE",
+	[rxrpc_skb_rx_got]		= "Rx GOT",
+	[rxrpc_skb_rx_lost]		= "Rx *L*",
+	[rxrpc_skb_rx_received]		= "Rx RCV",
+	[rxrpc_skb_rx_purged]		= "Rx PUR",
+	[rxrpc_skb_rx_rotated]		= "Rx ROT",
+	[rxrpc_skb_rx_seen]		= "Rx SEE",
+	[rxrpc_skb_tx_cleaned]		= "Tx CLN",
+	[rxrpc_skb_tx_freed]		= "Tx FRE",
+	[rxrpc_skb_tx_got]		= "Tx GOT",
+	[rxrpc_skb_tx_new]		= "Tx NEW",
+	[rxrpc_skb_tx_rotated]		= "Tx ROT",
+	[rxrpc_skb_tx_seen]		= "Tx SEE",
+};
+
+const char rxrpc_conn_traces[rxrpc_conn__nr_trace][4] = {
+	[rxrpc_conn_new_client]		= "NWc",
+	[rxrpc_conn_new_service]	= "NWs",
+	[rxrpc_conn_queued]		= "QUE",
+	[rxrpc_conn_seen]		= "SEE",
+	[rxrpc_conn_got]		= "GOT",
+	[rxrpc_conn_put_client]		= "PTc",
+	[rxrpc_conn_put_service]	= "PTs",
+};
+
+const char rxrpc_client_traces[rxrpc_client__nr_trace][7] = {
+	[rxrpc_client_activate_chans]	= "Activa",
+	[rxrpc_client_alloc]		= "Alloc ",
+	[rxrpc_client_chan_activate]	= "ChActv",
+	[rxrpc_client_chan_disconnect]	= "ChDisc",
+	[rxrpc_client_chan_pass]	= "ChPass",
+	[rxrpc_client_chan_unstarted]	= "ChUnst",
+	[rxrpc_client_cleanup]		= "Clean ",
+	[rxrpc_client_count]		= "Count ",
+	[rxrpc_client_discard]		= "Discar",
+	[rxrpc_client_duplicate]	= "Duplic",
+	[rxrpc_client_exposed]		= "Expose",
+	[rxrpc_client_replace]		= "Replac",
+	[rxrpc_client_to_active]	= "->Actv",
+	[rxrpc_client_to_culled]	= "->Cull",
+	[rxrpc_client_to_idle]		= "->Idle",
+	[rxrpc_client_to_inactive]	= "->Inac",
+	[rxrpc_client_to_waiting]	= "->Wait",
+	[rxrpc_client_uncount]		= "Uncoun",
+};
+
+const char rxrpc_transmit_traces[rxrpc_transmit__nr_trace][4] = {
+	[rxrpc_transmit_wait]		= "WAI",
+	[rxrpc_transmit_queue]		= "QUE",
+	[rxrpc_transmit_queue_last]	= "QLS",
+	[rxrpc_transmit_rotate]		= "ROT",
+	[rxrpc_transmit_rotate_last]	= "RLS",
+	[rxrpc_transmit_await_reply]	= "AWR",
+	[rxrpc_transmit_end]		= "END",
+};
+
+const char rxrpc_receive_traces[rxrpc_receive__nr_trace][4] = {
+	[rxrpc_receive_incoming]	= "INC",
+	[rxrpc_receive_queue]		= "QUE",
+	[rxrpc_receive_queue_last]	= "QLS",
+	[rxrpc_receive_front]		= "FRN",
+	[rxrpc_receive_rotate]		= "ROT",
+	[rxrpc_receive_end]		= "END",
+};
+
+const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5] = {
+	[rxrpc_recvmsg_enter]		= "ENTR",
+	[rxrpc_recvmsg_wait]		= "WAIT",
+	[rxrpc_recvmsg_dequeue]		= "DEQU",
+	[rxrpc_recvmsg_hole]		= "HOLE",
+	[rxrpc_recvmsg_next]		= "NEXT",
+	[rxrpc_recvmsg_cont]		= "CONT",
+	[rxrpc_recvmsg_full]		= "FULL",
+	[rxrpc_recvmsg_data_return]	= "DATA",
+	[rxrpc_recvmsg_terminal]	= "TERM",
+	[rxrpc_recvmsg_to_be_accepted]	= "TBAC",
+	[rxrpc_recvmsg_return]		= "RETN",
+};
+
+const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5] = {
+	[rxrpc_rtt_tx_ping]		= "PING",
+	[rxrpc_rtt_tx_data]		= "DATA",
+};
+
+const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5] = {
+	[rxrpc_rtt_rx_ping_response]	= "PONG",
+	[rxrpc_rtt_rx_requested_ack]	= "RACK",
+};
+
+const char rxrpc_timer_traces[rxrpc_timer__nr_trace][8] = {
+	[rxrpc_timer_begin]			= "Begin ",
+	[rxrpc_timer_expired]			= "*EXPR*",
+	[rxrpc_timer_init_for_reply]		= "IniRpl",
+	[rxrpc_timer_set_for_ack]		= "SetAck",
+	[rxrpc_timer_set_for_send]		= "SetTx ",
+	[rxrpc_timer_set_for_resend]		= "SetRTx",
+};
+
+const char rxrpc_propose_ack_traces[rxrpc_propose_ack__nr_trace][8] = {
+	[rxrpc_propose_ack_client_tx_end]	= "ClTxEnd",
+	[rxrpc_propose_ack_input_data]		= "DataIn ",
+	[rxrpc_propose_ack_ping_for_lost_ack]	= "LostAck",
+	[rxrpc_propose_ack_ping_for_lost_reply]	= "LostRpl",
+	[rxrpc_propose_ack_ping_for_params]	= "Params ",
+	[rxrpc_propose_ack_respond_to_ack]	= "Rsp2Ack",
+	[rxrpc_propose_ack_respond_to_ping]	= "Rsp2Png",
+	[rxrpc_propose_ack_retry_tx]		= "RetryTx",
+	[rxrpc_propose_ack_rotate_rx]		= "RxAck  ",
+	[rxrpc_propose_ack_terminal_ack]	= "ClTerm ",
+};
+
+const char *const rxrpc_propose_ack_outcomes[rxrpc_propose_ack__nr_outcomes] = {
+	[rxrpc_propose_ack_use]			= "",
+	[rxrpc_propose_ack_update]		= " Update",
+	[rxrpc_propose_ack_subsume]		= " Subsume",
+};
+
+const char rxrpc_congest_modes[NR__RXRPC_CONGEST_MODES][10] = {
+	[RXRPC_CALL_SLOW_START]		= "SlowStart",
+	[RXRPC_CALL_CONGEST_AVOIDANCE]	= "CongAvoid",
+	[RXRPC_CALL_PACKET_LOSS]	= "PktLoss  ",
+	[RXRPC_CALL_FAST_RETRANSMIT]	= "FastReTx ",
+};
+
+const char rxrpc_congest_changes[rxrpc_congest__nr_change][9] = {
+	[rxrpc_cong_begin_retransmission]	= " Retrans",
+	[rxrpc_cong_cleared_nacks]		= " Cleared",
+	[rxrpc_cong_new_low_nack]		= " NewLowN",
+	[rxrpc_cong_no_change]			= "",
+	[rxrpc_cong_progress]			= " Progres",
+	[rxrpc_cong_retransmit_again]		= " ReTxAgn",
+	[rxrpc_cong_rtt_window_end]		= " RttWinE",
+	[rxrpc_cong_saw_nack]			= " SawNack",
+};
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index f4bda06b7d2d..0d47db886f6e 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -14,336 +14,326 @@
 #include <linux/net.h>
 #include <linux/gfp.h>
 #include <linux/skbuff.h>
-#include <linux/circ_buf.h>
 #include <linux/export.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
-/*
- * Time till packet resend (in jiffies).
- */
-unsigned int rxrpc_resend_timeout = 4 * HZ;
-
-static int rxrpc_send_data(struct rxrpc_sock *rx,
-			   struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len);
+struct rxrpc_pkt_buffer {
+	struct rxrpc_wire_header whdr;
+	union {
+		struct {
+			struct rxrpc_ackpacket ack;
+			u8 acks[255];
+			u8 pad[3];
+		};
+		__be32 abort_code;
+	};
+	struct rxrpc_ackinfo ackinfo;
+};
 
 /*
- * extract control messages from the sendmsg() control buffer
+ * Fill out an ACK packet.
  */
-static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
-			      unsigned long *user_call_ID,
-			      enum rxrpc_command *command,
-			      u32 *abort_code,
-			      bool *_exclusive)
+static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
+				 struct rxrpc_pkt_buffer *pkt,
+				 rxrpc_seq_t *_hard_ack,
+				 rxrpc_seq_t *_top)
 {
-	struct cmsghdr *cmsg;
-	bool got_user_ID = false;
-	int len;
-
-	*command = RXRPC_CMD_SEND_DATA;
-
-	if (msg->msg_controllen == 0)
-		return -EINVAL;
-
-	for_each_cmsghdr(cmsg, msg) {
-		if (!CMSG_OK(msg, cmsg))
-			return -EINVAL;
-
-		len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
-		_debug("CMSG %d, %d, %d",
-		       cmsg->cmsg_level, cmsg->cmsg_type, len);
-
-		if (cmsg->cmsg_level != SOL_RXRPC)
-			continue;
-
-		switch (cmsg->cmsg_type) {
-		case RXRPC_USER_CALL_ID:
-			if (msg->msg_flags & MSG_CMSG_COMPAT) {
-				if (len != sizeof(u32))
-					return -EINVAL;
-				*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
-			} else {
-				if (len != sizeof(unsigned long))
-					return -EINVAL;
-				*user_call_ID = *(unsigned long *)
-					CMSG_DATA(cmsg);
-			}
-			_debug("User Call ID %lx", *user_call_ID);
-			got_user_ID = true;
-			break;
-
-		case RXRPC_ABORT:
-			if (*command != RXRPC_CMD_SEND_DATA)
-				return -EINVAL;
-			*command = RXRPC_CMD_SEND_ABORT;
-			if (len != sizeof(*abort_code))
-				return -EINVAL;
-			*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
-			_debug("Abort %x", *abort_code);
-			if (*abort_code == 0)
-				return -EINVAL;
-			break;
-
-		case RXRPC_ACCEPT:
-			if (*command != RXRPC_CMD_SEND_DATA)
-				return -EINVAL;
-			*command = RXRPC_CMD_ACCEPT;
-			if (len != 0)
-				return -EINVAL;
-			break;
-
-		case RXRPC_EXCLUSIVE_CALL:
-			*_exclusive = true;
-			if (len != 0)
-				return -EINVAL;
-			break;
-		default:
-			return -EINVAL;
-		}
+	rxrpc_serial_t serial;
+	rxrpc_seq_t hard_ack, top, seq;
+	int ix;
+	u32 mtu, jmax;
+	u8 *ackp = pkt->acks;
+
+	/* Barrier against rxrpc_input_data(). */
+	serial = call->ackr_serial;
+	hard_ack = READ_ONCE(call->rx_hard_ack);
+	top = smp_load_acquire(&call->rx_top);
+	*_hard_ack = hard_ack;
+	*_top = top;
+
+	pkt->ack.bufferSpace	= htons(8);
+	pkt->ack.maxSkew	= htons(call->ackr_skew);
+	pkt->ack.firstPacket	= htonl(hard_ack + 1);
+	pkt->ack.previousPacket	= htonl(call->ackr_prev_seq);
+	pkt->ack.serial		= htonl(serial);
+	pkt->ack.reason		= call->ackr_reason;
+	pkt->ack.nAcks		= top - hard_ack;
+
+	if (pkt->ack.reason == RXRPC_ACK_PING)
+		pkt->whdr.flags |= RXRPC_REQUEST_ACK;
+
+	if (after(top, hard_ack)) {
+		seq = hard_ack + 1;
+		do {
+			ix = seq & RXRPC_RXTX_BUFF_MASK;
+			if (call->rxtx_buffer[ix])
+				*ackp++ = RXRPC_ACK_TYPE_ACK;
+			else
+				*ackp++ = RXRPC_ACK_TYPE_NACK;
+			seq++;
+		} while (before_eq(seq, top));
 	}
 
-	if (!got_user_ID)
-		return -EINVAL;
-	_leave(" = 0");
-	return 0;
+	mtu = call->conn->params.peer->if_mtu;
+	mtu -= call->conn->params.peer->hdrsize;
+	jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
+	pkt->ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
+	pkt->ackinfo.maxMTU	= htonl(mtu);
+	pkt->ackinfo.rwind	= htonl(call->rx_winsize);
+	pkt->ackinfo.jumbo_max	= htonl(jmax);
+
+	*ackp++ = 0;
+	*ackp++ = 0;
+	*ackp++ = 0;
+	return top - hard_ack + 3;
 }
 
 /*
- * abort a call, sending an ABORT packet to the peer
+ * Send an ACK or ABORT call packet.
  */
-static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
+int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
 {
-	write_lock_bh(&call->state_lock);
-
-	if (call->state <= RXRPC_CALL_COMPLETE) {
-		call->state = RXRPC_CALL_LOCALLY_ABORTED;
-		call->local_abort = abort_code;
-		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-		del_timer_sync(&call->resend_timer);
-		del_timer_sync(&call->ack_timer);
-		clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
-		clear_bit(RXRPC_CALL_EV_ACK, &call->events);
-		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-		rxrpc_queue_call(call);
+	struct rxrpc_connection *conn = NULL;
+	struct rxrpc_pkt_buffer *pkt;
+	struct msghdr msg;
+	struct kvec iov[2];
+	rxrpc_serial_t serial;
+	rxrpc_seq_t hard_ack, top;
+	size_t len, n;
+	bool ping = false;
+	int ioc, ret;
+	u32 abort_code;
+
+	_enter("%u,%s", call->debug_id, rxrpc_pkts[type]);
+
+	spin_lock_bh(&call->lock);
+	if (call->conn)
+		conn = rxrpc_get_connection_maybe(call->conn);
+	spin_unlock_bh(&call->lock);
+	if (!conn)
+		return -ECONNRESET;
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt) {
+		rxrpc_put_connection(conn);
+		return -ENOMEM;
 	}
 
-	write_unlock_bh(&call->state_lock);
-}
-
-/*
- * Create a new client call for sendmsg().
- */
-static struct rxrpc_call *
-rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
-				  unsigned long user_call_ID, bool exclusive)
-{
-	struct rxrpc_conn_parameters cp;
-	struct rxrpc_call *call;
-	struct key *key;
-
-	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
+	msg.msg_name	= &call->peer->srx.transport;
+	msg.msg_namelen	= call->peer->srx.transport_len;
+	msg.msg_control	= NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags	= 0;
+
+	pkt->whdr.epoch		= htonl(conn->proto.epoch);
+	pkt->whdr.cid		= htonl(call->cid);
+	pkt->whdr.callNumber	= htonl(call->call_id);
+	pkt->whdr.seq		= 0;
+	pkt->whdr.type		= type;
+	pkt->whdr.flags		= conn->out_clientflag;
+	pkt->whdr.userStatus	= 0;
+	pkt->whdr.securityIndex	= call->security_ix;
+	pkt->whdr._rsvd		= 0;
+	pkt->whdr.serviceId	= htons(call->service_id);
+
+	iov[0].iov_base	= pkt;
+	iov[0].iov_len	= sizeof(pkt->whdr);
+	len = sizeof(pkt->whdr);
+
+	switch (type) {
+	case RXRPC_PACKET_TYPE_ACK:
+		spin_lock_bh(&call->lock);
+		if (!call->ackr_reason) {
+			spin_unlock_bh(&call->lock);
+			ret = 0;
+			goto out;
+		}
+		ping = (call->ackr_reason == RXRPC_ACK_PING);
+		n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top);
+		call->ackr_reason = 0;
 
-	_enter("");
+		spin_unlock_bh(&call->lock);
 
-	if (!msg->msg_name)
-		return ERR_PTR(-EDESTADDRREQ);
 
-	key = rx->key;
-	if (key && !rx->key->payload.data[0])
-		key = NULL;
+		pkt->whdr.flags |= RXRPC_SLOW_START_OK;
 
-	memset(&cp, 0, sizeof(cp));
-	cp.local		= rx->local;
-	cp.key			= rx->key;
-	cp.security_level	= rx->min_sec_level;
-	cp.exclusive		= rx->exclusive | exclusive;
-	cp.service_id		= srx->srx_service;
-	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
+		iov[0].iov_len += sizeof(pkt->ack) + n;
+		iov[1].iov_base = &pkt->ackinfo;
+		iov[1].iov_len	= sizeof(pkt->ackinfo);
+		len += sizeof(pkt->ack) + n + sizeof(pkt->ackinfo);
+		ioc = 2;
+		break;
 
-	_leave(" = %p\n", call);
-	return call;
-}
+	case RXRPC_PACKET_TYPE_ABORT:
+		abort_code = call->abort_code;
+		pkt->abort_code = htonl(abort_code);
+		iov[0].iov_len += sizeof(pkt->abort_code);
+		len += sizeof(pkt->abort_code);
+		ioc = 1;
+		break;
 
-/*
- * send a message forming part of a client call through an RxRPC socket
- * - caller holds the socket locked
- * - the socket may be either a client socket or a server socket
- */
-int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
-{
-	enum rxrpc_command cmd;
-	struct rxrpc_call *call;
-	unsigned long user_call_ID = 0;
-	bool exclusive = false;
-	u32 abort_code = 0;
-	int ret;
-
-	_enter("");
-
-	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
-				 &exclusive);
-	if (ret < 0)
-		return ret;
-
-	if (cmd == RXRPC_CMD_ACCEPT) {
-		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
-			return -EINVAL;
-		call = rxrpc_accept_call(rx, user_call_ID);
-		if (IS_ERR(call))
-			return PTR_ERR(call);
-		rxrpc_put_call(call);
-		return 0;
+	default:
+		BUG();
+		ret = -ENOANO;
+		goto out;
 	}
 
-	call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
-	if (!call) {
-		if (cmd != RXRPC_CMD_SEND_DATA)
-			return -EBADSLT;
-		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
-							 exclusive);
-		if (IS_ERR(call))
-			return PTR_ERR(call);
+	serial = atomic_inc_return(&conn->serial);
+	pkt->whdr.serial = htonl(serial);
+	switch (type) {
+	case RXRPC_PACKET_TYPE_ACK:
+		trace_rxrpc_tx_ack(call, serial,
+				   ntohl(pkt->ack.firstPacket),
+				   ntohl(pkt->ack.serial),
+				   pkt->ack.reason, pkt->ack.nAcks);
+		break;
 	}
 
-	_debug("CALL %d USR %lx ST %d on CONN %p",
-	       call->debug_id, call->user_call_ID, call->state, call->conn);
-
-	if (call->state >= RXRPC_CALL_COMPLETE) {
-		/* it's too late for this call */
-		ret = -ECONNRESET;
-	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
-		rxrpc_send_abort(call, abort_code);
-		ret = 0;
-	} else if (cmd != RXRPC_CMD_SEND_DATA) {
-		ret = -EINVAL;
-	} else if (!call->in_clientflag &&
-		   call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
-		/* request phase complete for this client call */
-		ret = -EPROTO;
-	} else if (call->in_clientflag &&
-		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
-		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
-		/* Reply phase not begun or not complete for service call. */
-		ret = -EPROTO;
-	} else {
-		ret = rxrpc_send_data(rx, call, msg, len);
+	if (ping) {
+		call->ackr_ping = serial;
+		smp_wmb();
+		/* We need to stick a time in before we send the packet in case
+		 * the reply gets back before kernel_sendmsg() completes - but
+		 * asking UDP to send the packet can take a relatively long
+		 * time, so we update the time after, on the assumption that
+		 * the packet transmission is more likely to happen towards the
+		 * end of the kernel_sendmsg() call.
+		 */
+		call->ackr_ping_time = ktime_get_real();
+		set_bit(RXRPC_CALL_PINGING, &call->flags);
+		trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
 	}
-
-	rxrpc_put_call(call);
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/**
- * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
- * @call: The call to send data through
- * @msg: The data to send
- * @len: The amount of data to send
- *
- * Allow a kernel service to send data on a call.  The call must be in an state
- * appropriate to sending data.  No control data should be supplied in @msg,
- * nor should an address be supplied.  MSG_MORE should be flagged if there's
- * more data to come, otherwise this data will end the transmission phase.
- */
-int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
-			   size_t len)
-{
-	int ret;
-
-	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
-
-	ASSERTCMP(msg->msg_name, ==, NULL);
-	ASSERTCMP(msg->msg_control, ==, NULL);
-
-	lock_sock(&call->socket->sk);
-
-	_debug("CALL %d USR %lx ST %d on CONN %p",
-	       call->debug_id, call->user_call_ID, call->state, call->conn);
-
-	if (call->state >= RXRPC_CALL_COMPLETE) {
-		ret = -ESHUTDOWN; /* it's too late for this call */
-	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
-		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
-		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
-		ret = -EPROTO; /* request phase complete for this client call */
-	} else {
-		ret = rxrpc_send_data(call->socket, call, msg, len);
+	ret = kernel_sendmsg(conn->params.local->socket,
+			     &msg, iov, ioc, len);
+	if (ping)
+		call->ackr_ping_time = ktime_get_real();
+
+	if (type == RXRPC_PACKET_TYPE_ACK &&
+	    call->state < RXRPC_CALL_COMPLETE) {
+		if (ret < 0) {
+			clear_bit(RXRPC_CALL_PINGING, &call->flags);
+			rxrpc_propose_ACK(call, pkt->ack.reason,
+					  ntohs(pkt->ack.maxSkew),
+					  ntohl(pkt->ack.serial),
+					  true, true,
+					  rxrpc_propose_ack_retry_tx);
+		} else {
+			spin_lock_bh(&call->lock);
+			if (after(hard_ack, call->ackr_consumed))
+				call->ackr_consumed = hard_ack;
+			if (after(top, call->ackr_seen))
+				call->ackr_seen = top;
+			spin_unlock_bh(&call->lock);
+		}
 	}
 
-	release_sock(&call->socket->sk);
-	_leave(" = %d", ret);
+out:
+	rxrpc_put_connection(conn);
+	kfree(pkt);
 	return ret;
 }
 
-EXPORT_SYMBOL(rxrpc_kernel_send_data);
-
-/**
- * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
- * @call: The call to be aborted
- * @abort_code: The abort code to stick into the ABORT packet
- *
- * Allow a kernel service to abort a call, if it's still in an abortable state.
- */
-void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
-{
-	_enter("{%d},%d", call->debug_id, abort_code);
-
-	lock_sock(&call->socket->sk);
-
-	_debug("CALL %d USR %lx ST %d on CONN %p",
-	       call->debug_id, call->user_call_ID, call->state, call->conn);
-
-	if (call->state < RXRPC_CALL_COMPLETE)
-		rxrpc_send_abort(call, abort_code);
-
-	release_sock(&call->socket->sk);
-	_leave("");
-}
-
-EXPORT_SYMBOL(rxrpc_kernel_abort_call);
-
 /*
  * send a packet through the transport endpoint
  */
-int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
+int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			   bool retrans)
 {
-	struct kvec iov[1];
+	struct rxrpc_connection *conn = call->conn;
+	struct rxrpc_wire_header whdr;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct msghdr msg;
+	struct kvec iov[2];
+	rxrpc_serial_t serial;
+	size_t len;
+	bool lost = false;
 	int ret, opt;
 
 	_enter(",{%d}", skb->len);
 
-	iov[0].iov_base = skb->head;
-	iov[0].iov_len = skb->len;
+	/* Each transmission of a Tx packet needs a new serial number */
+	serial = atomic_inc_return(&conn->serial);
+
+	whdr.epoch	= htonl(conn->proto.epoch);
+	whdr.cid	= htonl(call->cid);
+	whdr.callNumber	= htonl(call->call_id);
+	whdr.seq	= htonl(sp->hdr.seq);
+	whdr.serial	= htonl(serial);
+	whdr.type	= RXRPC_PACKET_TYPE_DATA;
+	whdr.flags	= sp->hdr.flags;
+	whdr.userStatus	= 0;
+	whdr.securityIndex = call->security_ix;
+	whdr._rsvd	= htons(sp->hdr._rsvd);
+	whdr.serviceId	= htons(call->service_id);
+
+	iov[0].iov_base = &whdr;
+	iov[0].iov_len = sizeof(whdr);
+	iov[1].iov_base = skb->head;
+	iov[1].iov_len = skb->len;
+	len = iov[0].iov_len + iov[1].iov_len;
 
-	msg.msg_name = &conn->params.peer->srx.transport;
-	msg.msg_namelen = conn->params.peer->srx.transport_len;
+	msg.msg_name = &call->peer->srx.transport;
+	msg.msg_namelen = call->peer->srx.transport_len;
 	msg.msg_control = NULL;
 	msg.msg_controllen = 0;
 	msg.msg_flags = 0;
 
-	/* send the packet with the don't fragment bit set if we currently
-	 * think it's small enough */
-	if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
-		down_read(&conn->params.local->defrag_sem);
-		/* send the packet by UDP
-		 * - returns -EMSGSIZE if UDP would have to fragment the packet
-		 *   to go out of the interface
-		 *   - in which case, we'll have processed the ICMP error
-		 *     message and update the peer record
-		 */
-		ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
-				     iov[0].iov_len);
+	/* If our RTT cache needs working on, request an ACK.  Also request
+	 * ACKs if a DATA packet appears to have been lost.
+	 */
+	if (retrans ||
+	    call->cong_mode == RXRPC_CALL_SLOW_START ||
+	    (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
+	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
+			 ktime_get_real()))
+		whdr.flags |= RXRPC_REQUEST_ACK;
+
+	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
+		static int lose;
+		if ((lose++ & 7) == 7) {
+			ret = 0;
+			lost = true;
+			goto done;
+		}
+	}
 
-		up_read(&conn->params.local->defrag_sem);
-		if (ret == -EMSGSIZE)
-			goto send_fragmentable;
+	_proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
 
-		_leave(" = %d [%u]", ret, conn->params.peer->maxdata);
-		return ret;
+	/* send the packet with the don't fragment bit set if we currently
+	 * think it's small enough */
+	if (iov[1].iov_len >= call->peer->maxdata)
+		goto send_fragmentable;
+
+	down_read(&conn->params.local->defrag_sem);
+	/* send the packet by UDP
+	 * - returns -EMSGSIZE if UDP would have to fragment the packet
+	 *   to go out of the interface
+	 *   - in which case, we'll have processed the ICMP error
+	 *     message and update the peer record
+	 */
+	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
+
+	up_read(&conn->params.local->defrag_sem);
+	if (ret == -EMSGSIZE)
+		goto send_fragmentable;
+
+done:
+	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
+			    retrans, lost);
+	if (ret >= 0) {
+		ktime_t now = ktime_get_real();
+		skb->tstamp = now;
+		smp_wmb();
+		sp->hdr.serial = serial;
+		if (whdr.flags & RXRPC_REQUEST_ACK) {
+			call->peer->rtt_last_req = now;
+			trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
+		}
 	}
+	_leave(" = %d [%u]", ret, call->peer->maxdata);
+	return ret;
 
 send_fragmentable:
 	/* attempt to send this message with fragmentation enabled */
@@ -358,8 +348,8 @@ send_fragmentable:
 					SOL_IP, IP_MTU_DISCOVER,
 					(char *)&opt, sizeof(opt));
 		if (ret == 0) {
-			ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
-					     iov[0].iov_len);
+			ret = kernel_sendmsg(conn->params.local->socket, &msg,
+					     iov, 2, len);
 
 			opt = IP_PMTUDISC_DO;
 			kernel_setsockopt(conn->params.local->socket, SOL_IP,
@@ -367,355 +357,82 @@ send_fragmentable:
 					  (char *)&opt, sizeof(opt));
 		}
 		break;
-	}
-
-	up_write(&conn->params.local->defrag_sem);
-	_leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
-	return ret;
-}
 
-/*
- * wait for space to appear in the transmit/ACK window
- * - caller holds the socket locked
- */
-static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
-				    struct rxrpc_call *call,
-				    long *timeo)
-{
-	DECLARE_WAITQUEUE(myself, current);
-	int ret;
-
-	_enter(",{%d},%ld",
-	       CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
-			  call->acks_winsz),
-	       *timeo);
-
-	add_wait_queue(&call->tx_waitq, &myself);
-
-	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		ret = 0;
-		if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
-			       call->acks_winsz) > 0)
-			break;
-		if (signal_pending(current)) {
-			ret = sock_intr_errno(*timeo);
-			break;
-		}
-
-		release_sock(&rx->sk);
-		*timeo = schedule_timeout(*timeo);
-		lock_sock(&rx->sk);
-	}
-
-	remove_wait_queue(&call->tx_waitq, &myself);
-	set_current_state(TASK_RUNNING);
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/*
- * attempt to schedule an instant Tx resend
- */
-static inline void rxrpc_instant_resend(struct rxrpc_call *call)
-{
-	read_lock_bh(&call->state_lock);
-	if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
-		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-		if (call->state < RXRPC_CALL_COMPLETE &&
-		    !test_and_set_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
-			rxrpc_queue_call(call);
-	}
-	read_unlock_bh(&call->state_lock);
-}
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		opt = IPV6_PMTUDISC_DONT;
+		ret = kernel_setsockopt(conn->params.local->socket,
+					SOL_IPV6, IPV6_MTU_DISCOVER,
+					(char *)&opt, sizeof(opt));
+		if (ret == 0) {
+			ret = kernel_sendmsg(conn->params.local->socket, &msg,
+					     iov, 1, iov[0].iov_len);
 
-/*
- * queue a packet for transmission, set the resend timer and attempt
- * to send the packet immediately
- */
-static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
-			       bool last)
-{
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	int ret;
-
-	_net("queue skb %p [%d]", skb, call->acks_head);
-
-	ASSERT(call->acks_window != NULL);
-	call->acks_window[call->acks_head] = (unsigned long) skb;
-	smp_wmb();
-	call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
-
-	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
-		_debug("________awaiting reply/ACK__________");
-		write_lock_bh(&call->state_lock);
-		switch (call->state) {
-		case RXRPC_CALL_CLIENT_SEND_REQUEST:
-			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
-			break;
-		case RXRPC_CALL_SERVER_ACK_REQUEST:
-			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
-			if (!last)
-				break;
-		case RXRPC_CALL_SERVER_SEND_REPLY:
-			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
-			break;
-		default:
-			break;
+			opt = IPV6_PMTUDISC_DO;
+			kernel_setsockopt(conn->params.local->socket,
+					  SOL_IPV6, IPV6_MTU_DISCOVER,
+					  (char *)&opt, sizeof(opt));
 		}
-		write_unlock_bh(&call->state_lock);
-	}
-
-	_proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
-
-	sp->need_resend = false;
-	sp->resend_at = jiffies + rxrpc_resend_timeout;
-	if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
-		_debug("run timer");
-		call->resend_timer.expires = sp->resend_at;
-		add_timer(&call->resend_timer);
-	}
-
-	/* attempt to cancel the rx-ACK timer, deferring reply transmission if
-	 * we're ACK'ing the request phase of an incoming call */
-	ret = -EAGAIN;
-	if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
-		/* the packet may be freed by rxrpc_process_call() before this
-		 * returns */
-		ret = rxrpc_send_data_packet(call->conn, skb);
-		_net("sent skb %p", skb);
-	} else {
-		_debug("failed to delete ACK timer");
-	}
-
-	if (ret < 0) {
-		_debug("need instant resend %d", ret);
-		sp->need_resend = true;
-		rxrpc_instant_resend(call);
+		break;
+#endif
 	}
 
-	_leave("");
-}
-
-/*
- * Convert a host-endian header into a network-endian header.
- */
-static void rxrpc_insert_header(struct sk_buff *skb)
-{
-	struct rxrpc_wire_header whdr;
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-
-	whdr.epoch	= htonl(sp->hdr.epoch);
-	whdr.cid	= htonl(sp->hdr.cid);
-	whdr.callNumber	= htonl(sp->hdr.callNumber);
-	whdr.seq	= htonl(sp->hdr.seq);
-	whdr.serial	= htonl(sp->hdr.serial);
-	whdr.type	= sp->hdr.type;
-	whdr.flags	= sp->hdr.flags;
-	whdr.userStatus	= sp->hdr.userStatus;
-	whdr.securityIndex = sp->hdr.securityIndex;
-	whdr._rsvd	= htons(sp->hdr._rsvd);
-	whdr.serviceId	= htons(sp->hdr.serviceId);
-
-	memcpy(skb->head, &whdr, sizeof(whdr));
+	up_write(&conn->params.local->defrag_sem);
+	goto done;
 }
 
 /*
- * send data through a socket
- * - must be called in process context
- * - caller holds the socket locked
+ * reject packets through the local endpoint
  */
-static int rxrpc_send_data(struct rxrpc_sock *rx,
-			   struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len)
+void rxrpc_reject_packets(struct rxrpc_local *local)
 {
+	struct sockaddr_rxrpc srx;
 	struct rxrpc_skb_priv *sp;
+	struct rxrpc_wire_header whdr;
 	struct sk_buff *skb;
-	struct sock *sk = &rx->sk;
-	long timeo;
-	bool more;
-	int ret, copied;
-
-	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
-
-	/* this should be in poll */
-	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
-
-	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
-		return -EPIPE;
-
-	more = msg->msg_flags & MSG_MORE;
-
-	skb = call->tx_pending;
-	call->tx_pending = NULL;
-
-	copied = 0;
-	do {
-		if (!skb) {
-			size_t size, chunk, max, space;
-
-			_debug("alloc");
-
-			if (CIRC_SPACE(call->acks_head,
-				       ACCESS_ONCE(call->acks_tail),
-				       call->acks_winsz) <= 0) {
-				ret = -EAGAIN;
-				if (msg->msg_flags & MSG_DONTWAIT)
-					goto maybe_error;
-				ret = rxrpc_wait_for_tx_window(rx, call,
-							       &timeo);
-				if (ret < 0)
-					goto maybe_error;
-			}
-
-			max = call->conn->params.peer->maxdata;
-			max -= call->conn->security_size;
-			max &= ~(call->conn->size_align - 1UL);
-
-			chunk = max;
-			if (chunk > msg_data_left(msg) && !more)
-				chunk = msg_data_left(msg);
-
-			space = chunk + call->conn->size_align;
-			space &= ~(call->conn->size_align - 1UL);
-
-			size = space + call->conn->header_size;
-
-			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
-
-			/* create a buffer that we can retain until it's ACK'd */
-			skb = sock_alloc_send_skb(
-				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
-			if (!skb)
-				goto maybe_error;
-
-			rxrpc_new_skb(skb);
-
-			_debug("ALLOC SEND %p", skb);
-
-			ASSERTCMP(skb->mark, ==, 0);
+	struct msghdr msg;
+	struct kvec iov[2];
+	size_t size;
+	__be32 code;
 
-			_debug("HS: %u", call->conn->header_size);
-			skb_reserve(skb, call->conn->header_size);
-			skb->len += call->conn->header_size;
+	_enter("%d", local->debug_id);
 
-			sp = rxrpc_skb(skb);
-			sp->remain = chunk;
-			if (sp->remain > skb_tailroom(skb))
-				sp->remain = skb_tailroom(skb);
+	iov[0].iov_base = &whdr;
+	iov[0].iov_len = sizeof(whdr);
+	iov[1].iov_base = &code;
+	iov[1].iov_len = sizeof(code);
+	size = sizeof(whdr) + sizeof(code);
 
-			_net("skb: hr %d, tr %d, hl %d, rm %d",
-			       skb_headroom(skb),
-			       skb_tailroom(skb),
-			       skb_headlen(skb),
-			       sp->remain);
+	msg.msg_name = &srx.transport;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags = 0;
 
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
-		}
+	memset(&whdr, 0, sizeof(whdr));
+	whdr.type = RXRPC_PACKET_TYPE_ABORT;
 
-		_debug("append");
+	while ((skb = skb_dequeue(&local->reject_queue))) {
+		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 		sp = rxrpc_skb(skb);
 
-		/* append next segment of data to the current buffer */
-		if (msg_data_left(msg) > 0) {
-			int copy = skb_tailroom(skb);
-			ASSERTCMP(copy, >, 0);
-			if (copy > msg_data_left(msg))
-				copy = msg_data_left(msg);
-			if (copy > sp->remain)
-				copy = sp->remain;
-
-			_debug("add");
-			ret = skb_add_data(skb, &msg->msg_iter, copy);
-			_debug("added");
-			if (ret < 0)
-				goto efault;
-			sp->remain -= copy;
-			skb->mark += copy;
-			copied += copy;
-		}
+		if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
+			msg.msg_namelen = srx.transport_len;
 
-		/* check for the far side aborting the call or a network error
-		 * occurring */
-		if (call->state > RXRPC_CALL_COMPLETE)
-			goto call_aborted;
-
-		/* add the packet to the send queue if it's now full */
-		if (sp->remain <= 0 ||
-		    (msg_data_left(msg) == 0 && !more)) {
-			struct rxrpc_connection *conn = call->conn;
-			uint32_t seq;
-			size_t pad;
-
-			/* pad out if we're using security */
-			if (conn->security_ix) {
-				pad = conn->security_size + skb->mark;
-				pad = conn->size_align - pad;
-				pad &= conn->size_align - 1;
-				_debug("pad %zu", pad);
-				if (pad)
-					memset(skb_put(skb, pad), 0, pad);
-			}
-
-			seq = atomic_inc_return(&call->sequence);
-
-			sp->hdr.epoch	= conn->proto.epoch;
-			sp->hdr.cid	= call->cid;
-			sp->hdr.callNumber = call->call_id;
-			sp->hdr.seq	= seq;
-			sp->hdr.serial	= atomic_inc_return(&conn->serial);
-			sp->hdr.type	= RXRPC_PACKET_TYPE_DATA;
-			sp->hdr.userStatus = 0;
-			sp->hdr.securityIndex = conn->security_ix;
-			sp->hdr._rsvd	= 0;
-			sp->hdr.serviceId = call->service_id;
-
-			sp->hdr.flags = conn->out_clientflag;
-			if (msg_data_left(msg) == 0 && !more)
-				sp->hdr.flags |= RXRPC_LAST_PACKET;
-			else if (CIRC_SPACE(call->acks_head,
-					    ACCESS_ONCE(call->acks_tail),
-					    call->acks_winsz) > 1)
-				sp->hdr.flags |= RXRPC_MORE_PACKETS;
-			if (more && seq & 1)
-				sp->hdr.flags |= RXRPC_REQUEST_ACK;
-
-			ret = conn->security->secure_packet(
-				call, skb, skb->mark,
-				skb->head + sizeof(struct rxrpc_wire_header));
-			if (ret < 0)
-				goto out;
-
-			rxrpc_insert_header(skb);
-			rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
-			skb = NULL;
-		}
-	} while (msg_data_left(msg) > 0);
+			code = htonl(skb->priority);
 
-success:
-	ret = copied;
-out:
-	call->tx_pending = skb;
-	_leave(" = %d", ret);
-	return ret;
+			whdr.epoch	= htonl(sp->hdr.epoch);
+			whdr.cid	= htonl(sp->hdr.cid);
+			whdr.callNumber	= htonl(sp->hdr.callNumber);
+			whdr.serviceId	= htons(sp->hdr.serviceId);
+			whdr.flags	= sp->hdr.flags;
+			whdr.flags	^= RXRPC_CLIENT_INITIATED;
+			whdr.flags	&= RXRPC_CLIENT_INITIATED;
 
-call_aborted:
-	rxrpc_free_skb(skb);
-	if (call->state == RXRPC_CALL_NETWORK_ERROR)
-		ret = call->error_report < RXRPC_LOCAL_ERROR_OFFSET ?
-			call->error_report :
-			call->error_report - RXRPC_LOCAL_ERROR_OFFSET;
-	else
-		ret = -ECONNABORTED;
-	_leave(" = %d", ret);
-	return ret;
+			kernel_sendmsg(local->socket, &msg, iov, 2, size);
+		}
 
-maybe_error:
-	if (copied)
-		goto success;
-	goto out;
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
+	}
 
-efault:
-	ret = -EFAULT;
-	goto out;
+	_leave("");
 }
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index 8940674b5e08..bf13b8470c9a 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -66,6 +66,32 @@ static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
 		}
 		break;
 
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		srx.transport.sin6.sin6_port = serr->port;
+		srx.transport_len = sizeof(struct sockaddr_in6);
+		switch (serr->ee.ee_origin) {
+		case SO_EE_ORIGIN_ICMP6:
+			_net("Rx ICMP6");
+			memcpy(&srx.transport.sin6.sin6_addr,
+			       skb_network_header(skb) + serr->addr_offset,
+			       sizeof(struct in6_addr));
+			break;
+		case SO_EE_ORIGIN_ICMP:
+			_net("Rx ICMP on v6 sock");
+			memcpy(srx.transport.sin6.sin6_addr.s6_addr + 12,
+			       skb_network_header(skb) + serr->addr_offset,
+			       sizeof(struct in_addr));
+			break;
+		default:
+			memcpy(&srx.transport.sin6.sin6_addr,
+			       &ipv6_hdr(skb)->saddr,
+			       sizeof(struct in6_addr));
+			break;
+		}
+		break;
+#endif
+
 	default:
 		BUG();
 	}
@@ -129,22 +155,21 @@ void rxrpc_error_report(struct sock *sk)
 		_leave("UDP socket errqueue empty");
 		return;
 	}
+	rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 	serr = SKB_EXT_ERR(skb);
 	if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 		_leave("UDP empty message");
-		kfree_skb(skb);
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		return;
 	}
 
-	rxrpc_new_skb(skb);
-
 	rcu_read_lock();
 	peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
 	if (peer && !rxrpc_get_peer_maybe(peer))
 		peer = NULL;
 	if (!peer) {
 		rcu_read_unlock();
-		rxrpc_free_skb(skb);
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		_leave(" [no peer]");
 		return;
 	}
@@ -154,7 +179,7 @@ void rxrpc_error_report(struct sock *sk)
 	     serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 		rxrpc_adjust_mtu(peer, serr);
 		rcu_read_unlock();
-		rxrpc_free_skb(skb);
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		rxrpc_put_peer(peer);
 		_leave(" [MTU update]");
 		return;
@@ -162,7 +187,7 @@ void rxrpc_error_report(struct sock *sk)
 
 	rxrpc_store_error(peer, serr);
 	rcu_read_unlock();
-	rxrpc_free_skb(skb);
+	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 
 	/* The ref we obtained is passed off to the work item */
 	rxrpc_queue_work(&peer->error_distributor);
@@ -248,13 +273,20 @@ void rxrpc_peer_error_distributor(struct work_struct *work)
 	struct rxrpc_peer *peer =
 		container_of(work, struct rxrpc_peer, error_distributor);
 	struct rxrpc_call *call;
-	int error_report;
+	enum rxrpc_call_completion compl;
+	int error;
 
 	_enter("");
 
-	error_report = READ_ONCE(peer->error_report);
+	error = READ_ONCE(peer->error_report);
+	if (error < RXRPC_LOCAL_ERROR_OFFSET) {
+		compl = RXRPC_CALL_NETWORK_ERROR;
+	} else {
+		compl = RXRPC_CALL_LOCAL_ERROR;
+		error -= RXRPC_LOCAL_ERROR_OFFSET;
+	}
 
-	_debug("ISSUE ERROR %d", error_report);
+	_debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);
 
 	spin_lock_bh(&peer->lock);
 
@@ -262,16 +294,10 @@ void rxrpc_peer_error_distributor(struct work_struct *work)
 		call = hlist_entry(peer->error_targets.first,
 				   struct rxrpc_call, error_link);
 		hlist_del_init(&call->error_link);
+		rxrpc_see_call(call);
 
-		write_lock(&call->state_lock);
-		if (call->state != RXRPC_CALL_COMPLETE &&
-		    call->state < RXRPC_CALL_NETWORK_ERROR) {
-			call->error_report = error_report;
-			call->state = RXRPC_CALL_NETWORK_ERROR;
-			set_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
-			rxrpc_queue_call(call);
-		}
-		write_unlock(&call->state_lock);
+		if (rxrpc_set_call_completion(call, compl, 0, error))
+			rxrpc_notify_socket(call);
 	}
 
 	spin_unlock_bh(&peer->lock);
@@ -279,3 +305,44 @@ void rxrpc_peer_error_distributor(struct work_struct *work)
 	rxrpc_put_peer(peer);
 	_leave("");
 }
+
+/*
+ * Add RTT information to cache.  This is called in softirq mode and has
+ * exclusive access to the peer RTT data.
+ */
+void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
+			rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
+			ktime_t send_time, ktime_t resp_time)
+{
+	struct rxrpc_peer *peer = call->peer;
+	s64 rtt;
+	u64 sum = peer->rtt_sum, avg;
+	u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
+
+	rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
+	if (rtt < 0)
+		return;
+
+	/* Replace the oldest datum in the RTT buffer */
+	sum -= peer->rtt_cache[cursor];
+	sum += rtt;
+	peer->rtt_cache[cursor] = rtt;
+	peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
+	peer->rtt_sum = sum;
+	if (usage < RXRPC_RTT_CACHE_SIZE) {
+		usage++;
+		peer->rtt_usage = usage;
+	}
+
+	/* Now recalculate the average */
+	if (usage == RXRPC_RTT_CACHE_SIZE) {
+		avg = sum / RXRPC_RTT_CACHE_SIZE;
+	} else {
+		avg = sum;
+		do_div(avg, usage);
+	}
+
+	peer->rtt = avg;
+	trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
+			   usage, avg);
+}
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index 538e9831c699..941b724d523b 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -16,12 +16,14 @@
 #include <linux/skbuff.h>
 #include <linux/udp.h>
 #include <linux/in.h>
+#include <linux/in6.h>
 #include <linux/slab.h>
 #include <linux/hashtable.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <net/ip.h>
 #include <net/route.h>
+#include <net/ip6_route.h>
 #include "ar-internal.h"
 
 static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
@@ -50,6 +52,13 @@ static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
 		size = sizeof(srx->transport.sin.sin_addr);
 		p = (u16 *)&srx->transport.sin.sin_addr;
 		break;
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		hash_key += (u16 __force)srx->transport.sin.sin_port;
+		size = sizeof(srx->transport.sin6.sin6_addr);
+		p = (u16 *)&srx->transport.sin6.sin6_addr;
+		break;
+#endif
 	default:
 		WARN(1, "AF_RXRPC: Unsupported transport address family\n");
 		return 0;
@@ -93,6 +102,14 @@ static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
 			memcmp(&peer->srx.transport.sin.sin_addr,
 			       &srx->transport.sin.sin_addr,
 			       sizeof(struct in_addr));
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		return ((u16 __force)peer->srx.transport.sin6.sin6_port -
+			(u16 __force)srx->transport.sin6.sin6_port) ?:
+			memcmp(&peer->srx.transport.sin6.sin6_addr,
+			       &srx->transport.sin6.sin6_addr,
+			       sizeof(struct in6_addr));
+#endif
 	default:
 		BUG();
 	}
@@ -130,17 +147,7 @@ struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
 
 	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 	if (peer) {
-		switch (srx->transport.family) {
-		case AF_INET:
-			_net("PEER %d {%d,%u,%pI4+%hu}",
-			     peer->debug_id,
-			     peer->srx.transport_type,
-			     peer->srx.transport.family,
-			     &peer->srx.transport.sin.sin_addr,
-			     ntohs(peer->srx.transport.sin.sin_port));
-			break;
-		}
-
+		_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
 		_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
 	}
 	return peer;
@@ -152,22 +159,53 @@ struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
  */
 static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
 {
+	struct dst_entry *dst;
 	struct rtable *rt;
-	struct flowi4 fl4;
+	struct flowi fl;
+	struct flowi4 *fl4 = &fl.u.ip4;
+#ifdef CONFIG_AF_RXRPC_IPV6
+	struct flowi6 *fl6 = &fl.u.ip6;
+#endif
 
 	peer->if_mtu = 1500;
 
-	rt = ip_route_output_ports(&init_net, &fl4, NULL,
-				   peer->srx.transport.sin.sin_addr.s_addr, 0,
-				   htons(7000), htons(7001),
-				   IPPROTO_UDP, 0, 0);
-	if (IS_ERR(rt)) {
-		_leave(" [route err %ld]", PTR_ERR(rt));
-		return;
+	memset(&fl, 0, sizeof(fl));
+	switch (peer->srx.transport.family) {
+	case AF_INET:
+		rt = ip_route_output_ports(
+			&init_net, fl4, NULL,
+			peer->srx.transport.sin.sin_addr.s_addr, 0,
+			htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
+		if (IS_ERR(rt)) {
+			_leave(" [route err %ld]", PTR_ERR(rt));
+			return;
+		}
+		dst = &rt->dst;
+		break;
+
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		fl6->flowi6_iif = LOOPBACK_IFINDEX;
+		fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
+		fl6->flowi6_proto = IPPROTO_UDP;
+		memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
+		       sizeof(struct in6_addr));
+		fl6->fl6_dport = htons(7001);
+		fl6->fl6_sport = htons(7000);
+		dst = ip6_route_output(&init_net, NULL, fl6);
+		if (IS_ERR(dst)) {
+			_leave(" [route err %ld]", PTR_ERR(dst));
+			return;
+		}
+		break;
+#endif
+
+	default:
+		BUG();
 	}
 
-	peer->if_mtu = dst_mtu(&rt->dst);
-	dst_release(&rt->dst);
+	peer->if_mtu = dst_mtu(dst);
+	dst_release(dst);
 
 	_leave(" [if_mtu %u]", peer->if_mtu);
 }
@@ -199,6 +237,41 @@ struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
 }
 
 /*
+ * Initialise peer record.
+ */
+static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
+{
+	peer->hash_key = hash_key;
+	rxrpc_assess_MTU_size(peer);
+	peer->mtu = peer->if_mtu;
+	peer->rtt_last_req = ktime_get_real();
+
+	switch (peer->srx.transport.family) {
+	case AF_INET:
+		peer->hdrsize = sizeof(struct iphdr);
+		break;
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		peer->hdrsize = sizeof(struct ipv6hdr);
+		break;
+#endif
+	default:
+		BUG();
+	}
+
+	switch (peer->srx.transport_type) {
+	case SOCK_DGRAM:
+		peer->hdrsize += sizeof(struct udphdr);
+		break;
+	default:
+		BUG();
+	}
+
+	peer->hdrsize += sizeof(struct rxrpc_wire_header);
+	peer->maxdata = peer->mtu - peer->hdrsize;
+}
+
+/*
  * Set up a new peer.
  */
 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
@@ -212,31 +285,40 @@ static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
 
 	peer = rxrpc_alloc_peer(local, gfp);
 	if (peer) {
-		peer->hash_key = hash_key;
 		memcpy(&peer->srx, srx, sizeof(*srx));
+		rxrpc_init_peer(peer, hash_key);
+	}
 
-		rxrpc_assess_MTU_size(peer);
-		peer->mtu = peer->if_mtu;
-
-		if (srx->transport.family == AF_INET) {
-			peer->hdrsize = sizeof(struct iphdr);
-			switch (srx->transport_type) {
-			case SOCK_DGRAM:
-				peer->hdrsize += sizeof(struct udphdr);
-				break;
-			default:
-				BUG();
-				break;
-			}
-		} else {
-			BUG();
-		}
+	_leave(" = %p", peer);
+	return peer;
+}
+
+/*
+ * Set up a new incoming peer.  The address is prestored in the preallocated
+ * peer.
+ */
+struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local,
+					      struct rxrpc_peer *prealloc)
+{
+	struct rxrpc_peer *peer;
+	unsigned long hash_key;
+
+	hash_key = rxrpc_peer_hash_key(local, &prealloc->srx);
+	prealloc->local = local;
+	rxrpc_init_peer(prealloc, hash_key);
 
-		peer->hdrsize += sizeof(struct rxrpc_wire_header);
-		peer->maxdata = peer->mtu - peer->hdrsize;
+	spin_lock(&rxrpc_peer_hash_lock);
+
+	/* Need to check that we aren't racing with someone else */
+	peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key);
+	if (peer && !rxrpc_get_peer_maybe(peer))
+		peer = NULL;
+	if (!peer) {
+		peer = prealloc;
+		hash_add_rcu(rxrpc_peer_hash, &peer->hash_link, hash_key);
 	}
 
-	_leave(" = %p", peer);
+	spin_unlock(&rxrpc_peer_hash_lock);
 	return peer;
 }
 
@@ -249,11 +331,7 @@ struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
 	struct rxrpc_peer *peer, *candidate;
 	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 
-	_enter("{%d,%d,%pI4+%hu}",
-	       srx->transport_type,
-	       srx->transport_len,
-	       &srx->transport.sin.sin_addr,
-	       ntohs(srx->transport.sin.sin_port));
+	_enter("{%pISp}", &srx->transport);
 
 	/* search the peer list first */
 	rcu_read_lock();
@@ -272,7 +350,7 @@ struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
 			return NULL;
 		}
 
-		spin_lock(&rxrpc_peer_hash_lock);
+		spin_lock_bh(&rxrpc_peer_hash_lock);
 
 		/* Need to check that we aren't racing with someone else */
 		peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
@@ -282,7 +360,7 @@ struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
 			hash_add_rcu(rxrpc_peer_hash,
 				     &candidate->hash_link, hash_key);
 
-		spin_unlock(&rxrpc_peer_hash_lock);
+		spin_unlock_bh(&rxrpc_peer_hash_lock);
 
 		if (peer)
 			kfree(candidate);
@@ -290,11 +368,7 @@ struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
 			peer = candidate;
 	}
 
-	_net("PEER %d {%d,%pI4+%hu}",
-	     peer->debug_id,
-	     peer->srx.transport_type,
-	     &peer->srx.transport.sin.sin_addr,
-	     ntohs(peer->srx.transport.sin.sin_port));
+	_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
 
 	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
 	return peer;
@@ -307,9 +381,24 @@ void __rxrpc_put_peer(struct rxrpc_peer *peer)
 {
 	ASSERT(hlist_empty(&peer->error_targets));
 
-	spin_lock(&rxrpc_peer_hash_lock);
+	spin_lock_bh(&rxrpc_peer_hash_lock);
 	hash_del_rcu(&peer->hash_link);
-	spin_unlock(&rxrpc_peer_hash_lock);
+	spin_unlock_bh(&rxrpc_peer_hash_lock);
 
 	kfree_rcu(peer, rcu);
 }
+
+/**
+ * rxrpc_kernel_get_peer - Get the peer address of a call
+ * @sock: The socket on which the call is in progress.
+ * @call: The call to query
+ * @_srx: Where to place the result
+ *
+ * Get the address of the remote peer in a call.
+ */
+void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
+			   struct sockaddr_rxrpc *_srx)
+{
+	*_srx = call->peer->srx;
+}
+EXPORT_SYMBOL(rxrpc_kernel_get_peer);
diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c
index ced5f07444e5..65cd980767fa 100644
--- a/net/rxrpc/proc.c
+++ b/net/rxrpc/proc.c
@@ -17,12 +17,12 @@
 static const char *const rxrpc_conn_states[RXRPC_CONN__NR_STATES] = {
 	[RXRPC_CONN_UNUSED]			= "Unused  ",
 	[RXRPC_CONN_CLIENT]			= "Client  ",
+	[RXRPC_CONN_SERVICE_PREALLOC]		= "SvPrealc",
 	[RXRPC_CONN_SERVICE_UNSECURED]		= "SvUnsec ",
 	[RXRPC_CONN_SERVICE_CHALLENGING]	= "SvChall ",
 	[RXRPC_CONN_SERVICE]			= "SvSecure",
 	[RXRPC_CONN_REMOTELY_ABORTED]		= "RmtAbort",
 	[RXRPC_CONN_LOCALLY_ABORTED]		= "LocAbort",
-	[RXRPC_CONN_NETWORK_ERROR]		= "NetError",
 };
 
 /*
@@ -30,6 +30,7 @@ static const char *const rxrpc_conn_states[RXRPC_CONN__NR_STATES] = {
  */
 static void *rxrpc_call_seq_start(struct seq_file *seq, loff_t *_pos)
 {
+	rcu_read_lock();
 	read_lock(&rxrpc_call_lock);
 	return seq_list_start_head(&rxrpc_calls, *_pos);
 }
@@ -42,17 +43,21 @@ static void *rxrpc_call_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 static void rxrpc_call_seq_stop(struct seq_file *seq, void *v)
 {
 	read_unlock(&rxrpc_call_lock);
+	rcu_read_unlock();
 }
 
 static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 {
-	struct rxrpc_connection *conn;
+	struct rxrpc_local *local;
+	struct rxrpc_sock *rx;
+	struct rxrpc_peer *peer;
 	struct rxrpc_call *call;
-	char lbuff[4 + 4 + 4 + 4 + 5 + 1], rbuff[4 + 4 + 4 + 4 + 5 + 1];
+	char lbuff[50], rbuff[50];
 
 	if (v == &rxrpc_calls) {
 		seq_puts(seq,
-			 "Proto Local                  Remote                "
+			 "Proto Local                                          "
+			 " Remote                                         "
 			 " SvID ConnID   CallID   End Use State    Abort   "
 			 " UserID\n");
 		return 0;
@@ -60,30 +65,35 @@ static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
 
 	call = list_entry(v, struct rxrpc_call, link);
 
-	sprintf(lbuff, "%pI4:%u",
-		&call->local->srx.transport.sin.sin_addr,
-		ntohs(call->local->srx.transport.sin.sin_port));
+	rx = rcu_dereference(call->socket);
+	if (rx) {
+		local = READ_ONCE(rx->local);
+		if (local)
+			sprintf(lbuff, "%pISpc", &local->srx.transport);
+		else
+			strcpy(lbuff, "no_local");
+	} else {
+		strcpy(lbuff, "no_socket");
+	}
 
-	conn = call->conn;
-	if (conn)
-		sprintf(rbuff, "%pI4:%u",
-			&conn->params.peer->srx.transport.sin.sin_addr,
-			ntohs(conn->params.peer->srx.transport.sin.sin_port));
+	peer = call->peer;
+	if (peer)
+		sprintf(rbuff, "%pISpc", &peer->srx.transport);
 	else
 		strcpy(rbuff, "no_connection");
 
 	seq_printf(seq,
-		   "UDP   %-22.22s %-22.22s %4x %08x %08x %s %3u"
+		   "UDP   %-47.47s %-47.47s %4x %08x %08x %s %3u"
 		   " %-8.8s %08x %lx\n",
 		   lbuff,
 		   rbuff,
 		   call->service_id,
 		   call->cid,
 		   call->call_id,
-		   call->in_clientflag ? "Svc" : "Clt",
+		   rxrpc_is_service_call(call) ? "Svc" : "Clt",
 		   atomic_read(&call->usage),
 		   rxrpc_call_states[call->state],
-		   call->remote_abort ?: call->local_abort,
+		   call->abort_code,
 		   call->user_call_ID);
 
 	return 0;
@@ -115,13 +125,13 @@ const struct file_operations rxrpc_call_seq_fops = {
 static void *rxrpc_connection_seq_start(struct seq_file *seq, loff_t *_pos)
 {
 	read_lock(&rxrpc_connection_lock);
-	return seq_list_start_head(&rxrpc_connections, *_pos);
+	return seq_list_start_head(&rxrpc_connection_proc_list, *_pos);
 }
 
 static void *rxrpc_connection_seq_next(struct seq_file *seq, void *v,
 				       loff_t *pos)
 {
-	return seq_list_next(v, &rxrpc_connections, pos);
+	return seq_list_next(v, &rxrpc_connection_proc_list, pos);
 }
 
 static void rxrpc_connection_seq_stop(struct seq_file *seq, void *v)
@@ -132,29 +142,31 @@ static void rxrpc_connection_seq_stop(struct seq_file *seq, void *v)
 static int rxrpc_connection_seq_show(struct seq_file *seq, void *v)
 {
 	struct rxrpc_connection *conn;
-	char lbuff[4 + 4 + 4 + 4 + 5 + 1], rbuff[4 + 4 + 4 + 4 + 5 + 1];
+	char lbuff[50], rbuff[50];
 
-	if (v == &rxrpc_connections) {
+	if (v == &rxrpc_connection_proc_list) {
 		seq_puts(seq,
-			 "Proto Local                  Remote                "
+			 "Proto Local                                          "
+			 " Remote                                         "
 			 " SvID ConnID   End Use State    Key     "
 			 " Serial   ISerial\n"
 			 );
 		return 0;
 	}
 
-	conn = list_entry(v, struct rxrpc_connection, link);
-
-	sprintf(lbuff, "%pI4:%u",
-		&conn->params.local->srx.transport.sin.sin_addr,
-		ntohs(conn->params.local->srx.transport.sin.sin_port));
+	conn = list_entry(v, struct rxrpc_connection, proc_link);
+	if (conn->state == RXRPC_CONN_SERVICE_PREALLOC) {
+		strcpy(lbuff, "no_local");
+		strcpy(rbuff, "no_connection");
+		goto print;
+	}
 
-	sprintf(rbuff, "%pI4:%u",
-		&conn->params.peer->srx.transport.sin.sin_addr,
-		ntohs(conn->params.peer->srx.transport.sin.sin_port));
+	sprintf(lbuff, "%pISpc", &conn->params.local->srx.transport);
 
+	sprintf(rbuff, "%pISpc", &conn->params.peer->srx.transport);
+print:
 	seq_printf(seq,
-		   "UDP   %-22.22s %-22.22s %4x %08x %s %3u"
+		   "UDP   %-47.47s %-47.47s %4x %08x %s %3u"
 		   " %s %08x %08x %08x\n",
 		   lbuff,
 		   rbuff,
@@ -165,7 +177,7 @@ static int rxrpc_connection_seq_show(struct seq_file *seq, void *v)
 		   rxrpc_conn_states[conn->state],
 		   key_serial(conn->params.key),
 		   atomic_read(&conn->serial),
-		   atomic_read(&conn->hi_serial));
+		   conn->hi_serial);
 
 	return 0;
 }
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 9ed66d533002..f05ea0a88076 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -19,399 +19,645 @@
 #include "ar-internal.h"
 
 /*
- * removal a call's user ID from the socket tree to make the user ID available
- * again and so that it won't be seen again in association with that call
+ * Post a call for attention by the socket or kernel service.  Further
+ * notifications are suppressed by putting recvmsg_link on a dummy queue.
  */
-void rxrpc_remove_user_ID(struct rxrpc_sock *rx, struct rxrpc_call *call)
+void rxrpc_notify_socket(struct rxrpc_call *call)
 {
-	_debug("RELEASE CALL %d", call->debug_id);
+	struct rxrpc_sock *rx;
+	struct sock *sk;
+
+	_enter("%d", call->debug_id);
+
+	if (!list_empty(&call->recvmsg_link))
+		return;
+
+	rcu_read_lock();
+
+	rx = rcu_dereference(call->socket);
+	sk = &rx->sk;
+	if (rx && sk->sk_state < RXRPC_CLOSE) {
+		if (call->notify_rx) {
+			call->notify_rx(sk, call, call->user_call_ID);
+		} else {
+			write_lock_bh(&rx->recvmsg_lock);
+			if (list_empty(&call->recvmsg_link)) {
+				rxrpc_get_call(call, rxrpc_call_got);
+				list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
+			}
+			write_unlock_bh(&rx->recvmsg_lock);
 
-	if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
-		write_lock_bh(&rx->call_lock);
-		rb_erase(&call->sock_node, &call->socket->calls);
-		clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
-		write_unlock_bh(&rx->call_lock);
+			if (!sock_flag(sk, SOCK_DEAD)) {
+				_debug("call %ps", sk->sk_data_ready);
+				sk->sk_data_ready(sk);
+			}
+		}
 	}
 
-	read_lock_bh(&call->state_lock);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
-	read_unlock_bh(&call->state_lock);
+	rcu_read_unlock();
+	_leave("");
 }
 
 /*
- * receive a message from an RxRPC socket
- * - we need to be careful about two or more threads calling recvmsg
- *   simultaneously
+ * Pass a call terminating message to userspace.
  */
-int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
-		  int flags)
+static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
 {
-	struct rxrpc_skb_priv *sp;
-	struct rxrpc_call *call = NULL, *continue_call = NULL;
-	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
-	struct sk_buff *skb;
-	long timeo;
-	int copy, ret, ullen, offset, copied = 0;
-	u32 abort_code;
-
-	DEFINE_WAIT(wait);
-
-	_enter(",,,%zu,%d", len, flags);
-
-	if (flags & (MSG_OOB | MSG_TRUNC))
-		return -EOPNOTSUPP;
-
-	ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
+	u32 tmp = 0;
+	int ret;
+
+	switch (call->completion) {
+	case RXRPC_CALL_SUCCEEDED:
+		ret = 0;
+		if (rxrpc_is_service_call(call))
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
+		break;
+	case RXRPC_CALL_REMOTELY_ABORTED:
+		tmp = call->abort_code;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
+		break;
+	case RXRPC_CALL_LOCALLY_ABORTED:
+		tmp = call->abort_code;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
+		break;
+	case RXRPC_CALL_NETWORK_ERROR:
+		tmp = call->error;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
+		break;
+	case RXRPC_CALL_LOCAL_ERROR:
+		tmp = call->error;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
+		break;
+	default:
+		pr_err("Invalid terminal call state %u\n", call->state);
+		BUG();
+		break;
+	}
 
-	timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
-	msg->msg_flags |= MSG_MORE;
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_terminal, call->rx_hard_ack,
+			    call->rx_pkt_offset, call->rx_pkt_len, ret);
+	return ret;
+}
 
-	lock_sock(&rx->sk);
+/*
+ * Pass back notification of a new call.  The call is added to the
+ * to-be-accepted list.  This means that the next call to be accepted might not
+ * be the last call seen awaiting acceptance, but unless we leave this on the
+ * front of the queue and block all other messages until someone gives us a
+ * user_ID for it, there's not a lot we can do.
+ */
+static int rxrpc_recvmsg_new_call(struct rxrpc_sock *rx,
+				  struct rxrpc_call *call,
+				  struct msghdr *msg, int flags)
+{
+	int tmp = 0, ret;
 
-	for (;;) {
-		/* return immediately if a client socket has no outstanding
-		 * calls */
-		if (RB_EMPTY_ROOT(&rx->calls)) {
-			if (copied)
-				goto out;
-			if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
-				release_sock(&rx->sk);
-				if (continue_call)
-					rxrpc_put_call(continue_call);
-				return -ENODATA;
-			}
-		}
+	ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &tmp);
 
-		/* get the next message on the Rx queue */
-		skb = skb_peek(&rx->sk.sk_receive_queue);
-		if (!skb) {
-			/* nothing remains on the queue */
-			if (copied &&
-			    (flags & MSG_PEEK || timeo == 0))
-				goto out;
+	if (ret == 0 && !(flags & MSG_PEEK)) {
+		_debug("to be accepted");
+		write_lock_bh(&rx->recvmsg_lock);
+		list_del_init(&call->recvmsg_link);
+		write_unlock_bh(&rx->recvmsg_lock);
 
-			/* wait for a message to turn up */
-			release_sock(&rx->sk);
-			prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
-						  TASK_INTERRUPTIBLE);
-			ret = sock_error(&rx->sk);
-			if (ret)
-				goto wait_error;
-
-			if (skb_queue_empty(&rx->sk.sk_receive_queue)) {
-				if (signal_pending(current))
-					goto wait_interrupted;
-				timeo = schedule_timeout(timeo);
-			}
-			finish_wait(sk_sleep(&rx->sk), &wait);
-			lock_sock(&rx->sk);
-			continue;
-		}
+		rxrpc_get_call(call, rxrpc_call_got);
+		write_lock(&rx->call_lock);
+		list_add_tail(&call->accept_link, &rx->to_be_accepted);
+		write_unlock(&rx->call_lock);
+	}
 
-	peek_next_packet:
-		sp = rxrpc_skb(skb);
-		call = sp->call;
-		ASSERT(call != NULL);
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_to_be_accepted, 1, 0, 0, ret);
+	return ret;
+}
 
-		_debug("next pkt %s", rxrpc_pkts[sp->hdr.type]);
+/*
+ * End the packet reception phase.
+ */
+static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
+{
+	_enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
 
-		/* make sure we wait for the state to be updated in this call */
-		spin_lock_bh(&call->lock);
-		spin_unlock_bh(&call->lock);
+	trace_rxrpc_receive(call, rxrpc_receive_end, 0, call->rx_top);
+	ASSERTCMP(call->rx_hard_ack, ==, call->rx_top);
 
-		if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
-			_debug("packet from released call");
-			if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-				BUG();
-			rxrpc_free_skb(skb);
-			continue;
-		}
+	if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) {
+		rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, serial, true, false,
+				  rxrpc_propose_ack_terminal_ack);
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+	}
 
-		/* determine whether to continue last data receive */
-		if (continue_call) {
-			_debug("maybe cont");
-			if (call != continue_call ||
-			    skb->mark != RXRPC_SKB_MARK_DATA) {
-				release_sock(&rx->sk);
-				rxrpc_put_call(continue_call);
-				_leave(" = %d [noncont]", copied);
-				return copied;
-			}
-		}
+	write_lock_bh(&call->state_lock);
 
-		rxrpc_get_call(call);
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+		__rxrpc_call_completed(call);
+		break;
 
-		/* copy the peer address and timestamp */
-		if (!continue_call) {
-			if (msg->msg_name) {
-				size_t len =
-					sizeof(call->conn->params.peer->srx);
-				memcpy(msg->msg_name,
-				       &call->conn->params.peer->srx, len);
-				msg->msg_namelen = len;
-			}
-			sock_recv_timestamp(msg, &rx->sk, skb);
-		}
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+		call->tx_phase = true;
+		call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
+		break;
+	default:
+		break;
+	}
 
-		/* receive the message */
-		if (skb->mark != RXRPC_SKB_MARK_DATA)
-			goto receive_non_data_message;
+	write_unlock_bh(&call->state_lock);
+}
 
-		_debug("recvmsg DATA #%u { %d, %d }",
-		       sp->hdr.seq, skb->len, sp->offset);
+/*
+ * Discard a packet we've used up and advance the Rx window by one.
+ */
+static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	rxrpc_serial_t serial;
+	rxrpc_seq_t hard_ack, top;
+	u8 flags;
+	int ix;
+
+	_enter("%d", call->debug_id);
+
+	hard_ack = call->rx_hard_ack;
+	top = smp_load_acquire(&call->rx_top);
+	ASSERT(before(hard_ack, top));
+
+	hard_ack++;
+	ix = hard_ack & RXRPC_RXTX_BUFF_MASK;
+	skb = call->rxtx_buffer[ix];
+	rxrpc_see_skb(skb, rxrpc_skb_rx_rotated);
+	sp = rxrpc_skb(skb);
+	flags = sp->hdr.flags;
+	serial = sp->hdr.serial;
+	if (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO)
+		serial += (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) - 1;
+
+	call->rxtx_buffer[ix] = NULL;
+	call->rxtx_annotations[ix] = 0;
+	/* Barrier against rxrpc_input_data(). */
+	smp_store_release(&call->rx_hard_ack, hard_ack);
+
+	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
+
+	_debug("%u,%u,%02x", hard_ack, top, flags);
+	trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
+	if (flags & RXRPC_LAST_PACKET) {
+		rxrpc_end_rx_phase(call, serial);
+	} else {
+		/* Check to see if there's an ACK that needs sending. */
+		if (after_eq(hard_ack, call->ackr_consumed + 2) ||
+		    after_eq(top, call->ackr_seen + 2) ||
+		    (hard_ack == top && after(hard_ack, call->ackr_consumed)))
+			rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, 0, serial,
+					  true, false,
+					  rxrpc_propose_ack_rotate_rx);
+		if (call->ackr_reason)
+			rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+	}
+}
 
-		if (!continue_call) {
-			/* only set the control data once per recvmsg() */
-			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
-				       ullen, &call->user_call_ID);
-			if (ret < 0)
-				goto copy_error;
-			ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
-		}
+/*
+ * Decrypt and verify a (sub)packet.  The packet's length may be changed due to
+ * padding, but if this is the case, the packet length will be resident in the
+ * socket buffer.  Note that we can't modify the master skb info as the skb may
+ * be the home to multiple subpackets.
+ */
+static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			       u8 annotation,
+			       unsigned int offset, unsigned int len)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	rxrpc_seq_t seq = sp->hdr.seq;
+	u16 cksum = sp->hdr.cksum;
 
-		ASSERTCMP(sp->hdr.seq, >=, call->rx_data_recv);
-		ASSERTCMP(sp->hdr.seq, <=, call->rx_data_recv + 1);
-		call->rx_data_recv = sp->hdr.seq;
+	_enter("");
 
-		ASSERTCMP(sp->hdr.seq, >, call->rx_data_eaten);
+	/* For all but the head jumbo subpacket, the security checksum is in a
+	 * jumbo header immediately prior to the data.
+	 */
+	if ((annotation & RXRPC_RX_ANNO_JUMBO) > 1) {
+		__be16 tmp;
+		if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0)
+			BUG();
+		cksum = ntohs(tmp);
+		seq += (annotation & RXRPC_RX_ANNO_JUMBO) - 1;
+	}
 
-		offset = sp->offset;
-		copy = skb->len - offset;
-		if (copy > len - copied)
-			copy = len - copied;
+	return call->conn->security->verify_packet(call, skb, offset, len,
+						   seq, cksum);
+}
 
-		ret = skb_copy_datagram_msg(skb, offset, msg, copy);
+/*
+ * Locate the data within a packet.  This is complicated by:
+ *
+ * (1) An skb may contain a jumbo packet - so we have to find the appropriate
+ *     subpacket.
+ *
+ * (2) The (sub)packets may be encrypted and, if so, the encrypted portion
+ *     contains an extra header which includes the true length of the data,
+ *     excluding any encrypted padding.
+ */
+static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
+			     u8 *_annotation,
+			     unsigned int *_offset, unsigned int *_len)
+{
+	unsigned int offset = sizeof(struct rxrpc_wire_header);
+	unsigned int len = *_len;
+	int ret;
+	u8 annotation = *_annotation;
+
+	/* Locate the subpacket */
+	len = skb->len - offset;
+	if ((annotation & RXRPC_RX_ANNO_JUMBO) > 0) {
+		offset += (((annotation & RXRPC_RX_ANNO_JUMBO) - 1) *
+			   RXRPC_JUMBO_SUBPKTLEN);
+		len = (annotation & RXRPC_RX_ANNO_JLAST) ?
+			skb->len - offset : RXRPC_JUMBO_SUBPKTLEN;
+	}
 
+	if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) {
+		ret = rxrpc_verify_packet(call, skb, annotation, offset, len);
 		if (ret < 0)
-			goto copy_error;
-
-		/* handle piecemeal consumption of data packets */
-		_debug("copied %d+%d", copy, copied);
+			return ret;
+		*_annotation |= RXRPC_RX_ANNO_VERIFIED;
+	}
 
-		offset += copy;
-		copied += copy;
+	*_offset = offset;
+	*_len = len;
+	call->conn->security->locate_data(call, skb, _offset, _len);
+	return 0;
+}
 
-		if (!(flags & MSG_PEEK))
-			sp->offset = offset;
+/*
+ * Deliver messages to a call.  This keeps processing packets until the buffer
+ * is filled and we find either more DATA (returns 0) or the end of the DATA
+ * (returns 1).  If more packets are required, it returns -EAGAIN.
+ */
+static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
+			      struct msghdr *msg, struct iov_iter *iter,
+			      size_t len, int flags, size_t *_offset)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	rxrpc_seq_t hard_ack, top, seq;
+	size_t remain;
+	bool last;
+	unsigned int rx_pkt_offset, rx_pkt_len;
+	int ix, copy, ret = -EAGAIN, ret2;
+
+	rx_pkt_offset = call->rx_pkt_offset;
+	rx_pkt_len = call->rx_pkt_len;
+
+	if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
+		seq = call->rx_hard_ack;
+		ret = 1;
+		goto done;
+	}
 
-		if (sp->offset < skb->len) {
-			_debug("buffer full");
-			ASSERTCMP(copied, ==, len);
+	/* Barriers against rxrpc_input_data(). */
+	hard_ack = call->rx_hard_ack;
+	top = smp_load_acquire(&call->rx_top);
+	for (seq = hard_ack + 1; before_eq(seq, top); seq++) {
+		ix = seq & RXRPC_RXTX_BUFF_MASK;
+		skb = call->rxtx_buffer[ix];
+		if (!skb) {
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_hole, seq,
+					    rx_pkt_offset, rx_pkt_len, 0);
 			break;
 		}
+		smp_rmb();
+		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
+		sp = rxrpc_skb(skb);
 
-		/* we transferred the whole data packet */
 		if (!(flags & MSG_PEEK))
-			rxrpc_kernel_data_consumed(call, skb);
-
-		if (sp->hdr.flags & RXRPC_LAST_PACKET) {
-			_debug("last");
-			if (rxrpc_conn_is_client(call->conn)) {
-				 /* last byte of reply received */
-				ret = copied;
-				goto terminal_message;
+			trace_rxrpc_receive(call, rxrpc_receive_front,
+					    sp->hdr.serial, seq);
+
+		if (msg)
+			sock_recv_timestamp(msg, sock->sk, skb);
+
+		if (rx_pkt_offset == 0) {
+			ret2 = rxrpc_locate_data(call, skb,
+						 &call->rxtx_annotations[ix],
+						 &rx_pkt_offset, &rx_pkt_len);
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_next, seq,
+					    rx_pkt_offset, rx_pkt_len, ret2);
+			if (ret2 < 0) {
+				ret = ret2;
+				goto out;
 			}
+		} else {
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_cont, seq,
+					    rx_pkt_offset, rx_pkt_len, 0);
+		}
 
-			/* last bit of request received */
-			if (!(flags & MSG_PEEK)) {
-				_debug("eat packet");
-				if (skb_dequeue(&rx->sk.sk_receive_queue) !=
-				    skb)
-					BUG();
-				rxrpc_free_skb(skb);
+		/* We have to handle short, empty and used-up DATA packets. */
+		remain = len - *_offset;
+		copy = rx_pkt_len;
+		if (copy > remain)
+			copy = remain;
+		if (copy > 0) {
+			ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
+						      copy);
+			if (ret2 < 0) {
+				ret = ret2;
+				goto out;
 			}
-			msg->msg_flags &= ~MSG_MORE;
-			break;
+
+			/* handle piecemeal consumption of data packets */
+			rx_pkt_offset += copy;
+			rx_pkt_len -= copy;
+			*_offset += copy;
 		}
 
-		/* move on to the next data message */
-		_debug("next");
-		if (!continue_call)
-			continue_call = sp->call;
-		else
-			rxrpc_put_call(call);
-		call = NULL;
-
-		if (flags & MSG_PEEK) {
-			_debug("peek next");
-			skb = skb->next;
-			if (skb == (struct sk_buff *) &rx->sk.sk_receive_queue)
-				break;
-			goto peek_next_packet;
+		if (rx_pkt_len > 0) {
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_full, seq,
+					    rx_pkt_offset, rx_pkt_len, 0);
+			ASSERTCMP(*_offset, ==, len);
+			ret = 0;
+			break;
 		}
 
-		_debug("eat packet");
-		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-			BUG();
-		rxrpc_free_skb(skb);
+		/* The whole packet has been transferred. */
+		last = sp->hdr.flags & RXRPC_LAST_PACKET;
+		if (!(flags & MSG_PEEK))
+			rxrpc_rotate_rx_window(call);
+		rx_pkt_offset = 0;
+		rx_pkt_len = 0;
+
+		if (last) {
+			ASSERTCMP(seq, ==, READ_ONCE(call->rx_top));
+			ret = 1;
+			goto out;
+		}
 	}
 
-	/* end of non-terminal data packet reception for the moment */
-	_debug("end rcv data");
 out:
-	release_sock(&rx->sk);
-	if (call)
-		rxrpc_put_call(call);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	_leave(" = %d [data]", copied);
-	return copied;
-
-	/* handle non-DATA messages such as aborts, incoming connections and
-	 * final ACKs */
-receive_non_data_message:
-	_debug("non-data");
-
-	if (skb->mark == RXRPC_SKB_MARK_NEW_CALL) {
-		_debug("RECV NEW CALL");
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &abort_code);
-		if (ret < 0)
-			goto copy_error;
-		if (!(flags & MSG_PEEK)) {
-			if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-				BUG();
-			rxrpc_free_skb(skb);
-		}
-		goto out;
+	if (!(flags & MSG_PEEK)) {
+		call->rx_pkt_offset = rx_pkt_offset;
+		call->rx_pkt_len = rx_pkt_len;
 	}
+done:
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_data_return, seq,
+			    rx_pkt_offset, rx_pkt_len, ret);
+	return ret;
+}
 
-	ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
-		       ullen, &call->user_call_ID);
-	if (ret < 0)
-		goto copy_error;
-	ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
+/*
+ * Receive a message from an RxRPC socket
+ * - we need to be careful about two or more threads calling recvmsg
+ *   simultaneously
+ */
+int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+		  int flags)
+{
+	struct rxrpc_call *call;
+	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
+	struct list_head *l;
+	size_t copied = 0;
+	long timeo;
+	int ret;
+
+	DEFINE_WAIT(wait);
+
+	trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_enter, 0, 0, 0, 0);
+
+	if (flags & (MSG_OOB | MSG_TRUNC))
+		return -EOPNOTSUPP;
+
+	timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
+
+try_again:
+	lock_sock(&rx->sk);
+
+	/* Return immediately if a client socket has no outstanding calls */
+	if (RB_EMPTY_ROOT(&rx->calls) &&
+	    list_empty(&rx->recvmsg_q) &&
+	    rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
+		release_sock(&rx->sk);
+		return -ENODATA;
+	}
+
+	if (list_empty(&rx->recvmsg_q)) {
+		ret = -EWOULDBLOCK;
+		if (timeo == 0) {
+			call = NULL;
+			goto error_no_call;
+		}
+
+		release_sock(&rx->sk);
+
+		/* Wait for something to happen */
+		prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
+					  TASK_INTERRUPTIBLE);
+		ret = sock_error(&rx->sk);
+		if (ret)
+			goto wait_error;
+
+		if (list_empty(&rx->recvmsg_q)) {
+			if (signal_pending(current))
+				goto wait_interrupted;
+			trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_wait,
+					    0, 0, 0, 0);
+			timeo = schedule_timeout(timeo);
+		}
+		finish_wait(sk_sleep(&rx->sk), &wait);
+		goto try_again;
+	}
 
-	switch (skb->mark) {
-	case RXRPC_SKB_MARK_DATA:
+	/* Find the next call and dequeue it if we're not just peeking.  If we
+	 * do dequeue it, that comes with a ref that we will need to release.
+	 */
+	write_lock_bh(&rx->recvmsg_lock);
+	l = rx->recvmsg_q.next;
+	call = list_entry(l, struct rxrpc_call, recvmsg_link);
+	if (!(flags & MSG_PEEK))
+		list_del_init(&call->recvmsg_link);
+	else
+		rxrpc_get_call(call, rxrpc_call_got);
+	write_unlock_bh(&rx->recvmsg_lock);
+
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0);
+
+	if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 		BUG();
-	case RXRPC_SKB_MARK_FINAL_ACK:
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_BUSY:
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_REMOTE_ABORT:
-		abort_code = call->remote_abort;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_LOCAL_ABORT:
-		abort_code = call->local_abort;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_NET_ERROR:
-		_debug("RECV NET ERROR %d", sp->error);
-		abort_code = sp->error;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &abort_code);
+
+	if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
+		if (flags & MSG_CMSG_COMPAT) {
+			unsigned int id32 = call->user_call_ID;
+
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+				       sizeof(unsigned int), &id32);
+		} else {
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+				       sizeof(unsigned long),
+				       &call->user_call_ID);
+		}
+		if (ret < 0)
+			goto error;
+	}
+
+	if (msg->msg_name) {
+		size_t len = sizeof(call->conn->params.peer->srx);
+		memcpy(msg->msg_name, &call->conn->params.peer->srx, len);
+		msg->msg_namelen = len;
+	}
+
+	switch (call->state) {
+	case RXRPC_CALL_SERVER_ACCEPTING:
+		ret = rxrpc_recvmsg_new_call(rx, call, msg, flags);
 		break;
-	case RXRPC_SKB_MARK_LOCAL_ERROR:
-		_debug("RECV LOCAL ERROR %d", sp->error);
-		abort_code = sp->error;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
-			       &abort_code);
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+	case RXRPC_CALL_SERVER_ACK_REQUEST:
+		ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
+					 flags, &copied);
+		if (ret == -EAGAIN)
+			ret = 0;
+
+		if (after(call->rx_top, call->rx_hard_ack) &&
+		    call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK])
+			rxrpc_notify_socket(call);
 		break;
 	default:
-		pr_err("Unknown packet mark %u\n", skb->mark);
-		BUG();
+		ret = 0;
 		break;
 	}
 
 	if (ret < 0)
-		goto copy_error;
-
-terminal_message:
-	_debug("terminal");
-	msg->msg_flags &= ~MSG_MORE;
-	msg->msg_flags |= MSG_EOR;
+		goto error;
 
-	if (!(flags & MSG_PEEK)) {
-		_net("free terminal skb %p", skb);
-		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-			BUG();
-		rxrpc_free_skb(skb);
-		rxrpc_remove_user_ID(rx, call);
+	if (call->state == RXRPC_CALL_COMPLETE) {
+		ret = rxrpc_recvmsg_term(call, msg);
+		if (ret < 0)
+			goto error;
+		if (!(flags & MSG_PEEK))
+			rxrpc_release_call(rx, call);
+		msg->msg_flags |= MSG_EOR;
+		ret = 1;
 	}
 
-	release_sock(&rx->sk);
-	rxrpc_put_call(call);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	_leave(" = %d", ret);
-	return ret;
+	if (ret == 0)
+		msg->msg_flags |= MSG_MORE;
+	else
+		msg->msg_flags &= ~MSG_MORE;
+	ret = copied;
 
-copy_error:
-	_debug("copy error");
+error:
+	rxrpc_put_call(call, rxrpc_call_put);
+error_no_call:
 	release_sock(&rx->sk);
-	rxrpc_put_call(call);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	_leave(" = %d", ret);
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
 	return ret;
 
 wait_interrupted:
 	ret = sock_intr_errno(timeo);
 wait_error:
 	finish_wait(sk_sleep(&rx->sk), &wait);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	if (copied)
-		copied = ret;
-	_leave(" = %d [waitfail %d]", copied, ret);
-	return copied;
-
+	call = NULL;
+	goto error_no_call;
 }
 
 /**
- * rxrpc_kernel_is_data_last - Determine if data message is last one
- * @skb: Message holding data
+ * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
+ * @sock: The socket that the call exists on
+ * @call: The call to send data through
+ * @buf: The buffer to receive into
+ * @size: The size of the buffer, including data already read
+ * @_offset: The running offset into the buffer.
+ * @want_more: True if more data is expected to be read
+ * @_abort: Where the abort code is stored if -ECONNABORTED is returned
  *
- * Determine if data message is last one for the parent call.
+ * Allow a kernel service to receive data and pick up information about the
+ * state of a call.  Returns 0 if got what was asked for and there's more
+ * available, 1 if we got what was asked for and we're at the end of the data
+ * and -EAGAIN if we need more data.
+ *
+ * Note that we may return -EAGAIN to drain empty packets at the end of the
+ * data, even if we've already copied over the requested data.
+ *
+ * This function adds the amount it transfers to *_offset, so this should be
+ * precleared as appropriate.  Note that the amount remaining in the buffer is
+ * taken to be size - *_offset.
+ *
+ * *_abort should also be initialised to 0.
  */
-bool rxrpc_kernel_is_data_last(struct sk_buff *skb)
+int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
+			   void *buf, size_t size, size_t *_offset,
+			   bool want_more, u32 *_abort)
 {
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct iov_iter iter;
+	struct kvec iov;
+	int ret;
 
-	ASSERTCMP(skb->mark, ==, RXRPC_SKB_MARK_DATA);
+	_enter("{%d,%s},%zu/%zu,%d",
+	       call->debug_id, rxrpc_call_states[call->state],
+	       *_offset, size, want_more);
 
-	return sp->hdr.flags & RXRPC_LAST_PACKET;
-}
+	ASSERTCMP(*_offset, <=, size);
+	ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING);
 
-EXPORT_SYMBOL(rxrpc_kernel_is_data_last);
+	iov.iov_base = buf + *_offset;
+	iov.iov_len = size - *_offset;
+	iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset);
 
-/**
- * rxrpc_kernel_get_abort_code - Get the abort code from an RxRPC abort message
- * @skb: Message indicating an abort
- *
- * Get the abort code from an RxRPC abort message.
- */
-u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb)
-{
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	lock_sock(sock->sk);
+
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+	case RXRPC_CALL_SERVER_ACK_REQUEST:
+		ret = rxrpc_recvmsg_data(sock, call, NULL, &iter, size, 0,
+					 _offset);
+		if (ret < 0)
+			goto out;
+
+		/* We can only reach here with a partially full buffer if we
+		 * have reached the end of the data.  We must otherwise have a
+		 * full buffer or have been given -EAGAIN.
+		 */
+		if (ret == 1) {
+			if (*_offset < size)
+				goto short_data;
+			if (!want_more)
+				goto read_phase_complete;
+			ret = 0;
+			goto out;
+		}
+
+		if (!want_more)
+			goto excess_data;
+		goto out;
+
+	case RXRPC_CALL_COMPLETE:
+		goto call_complete;
 
-	switch (skb->mark) {
-	case RXRPC_SKB_MARK_REMOTE_ABORT:
-		return sp->call->remote_abort;
-	case RXRPC_SKB_MARK_LOCAL_ABORT:
-		return sp->call->local_abort;
 	default:
-		BUG();
+		ret = -EINPROGRESS;
+		goto out;
 	}
-}
-
-EXPORT_SYMBOL(rxrpc_kernel_get_abort_code);
 
-/**
- * rxrpc_kernel_get_error - Get the error number from an RxRPC error message
- * @skb: Message indicating an error
- *
- * Get the error number from an RxRPC error message.
- */
-int rxrpc_kernel_get_error_number(struct sk_buff *skb)
-{
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+read_phase_complete:
+	ret = 1;
+out:
+	release_sock(sock->sk);
+	_leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
+	return ret;
 
-	return sp->error;
+short_data:
+	ret = -EBADMSG;
+	goto out;
+excess_data:
+	ret = -EMSGSIZE;
+	goto out;
+call_complete:
+	*_abort = call->abort_code;
+	ret = call->error;
+	if (call->completion == RXRPC_CALL_SUCCEEDED) {
+		ret = 1;
+		if (size > 0)
+			ret = -ECONNRESET;
+	}
+	goto out;
 }
-
-EXPORT_SYMBOL(rxrpc_kernel_get_error_number);
+EXPORT_SYMBOL(rxrpc_kernel_recv_data);
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 63afa9e9cc08..627abed5f999 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -80,12 +80,10 @@ static int rxkad_init_connection_security(struct rxrpc_connection *conn)
 	case RXRPC_SECURITY_AUTH:
 		conn->size_align = 8;
 		conn->security_size = sizeof(struct rxkad_level1_hdr);
-		conn->header_size += sizeof(struct rxkad_level1_hdr);
 		break;
 	case RXRPC_SECURITY_ENCRYPT:
 		conn->size_align = 8;
 		conn->security_size = sizeof(struct rxkad_level2_hdr);
-		conn->header_size += sizeof(struct rxkad_level2_hdr);
 		break;
 	default:
 		ret = -EKEYREJECTED;
@@ -161,7 +159,7 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
 
 	_enter("");
 
-	check = sp->hdr.seq ^ sp->hdr.callNumber;
+	check = sp->hdr.seq ^ call->call_id;
 	data_size |= (u32)check << 16;
 
 	hdr.data_size = htonl(data_size);
@@ -205,7 +203,7 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
 
 	_enter("");
 
-	check = sp->hdr.seq ^ sp->hdr.callNumber;
+	check = sp->hdr.seq ^ call->call_id;
 
 	rxkhdr.data_size = htonl(data_size | (u32)check << 16);
 	rxkhdr.checksum = 0;
@@ -275,9 +273,9 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
 	memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
 
 	/* calculate the security checksum */
-	x = call->channel << (32 - RXRPC_CIDSHIFT);
+	x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
 	x |= sp->hdr.seq & 0x3fffffff;
-	call->crypto_buf[0] = htonl(sp->hdr.callNumber);
+	call->crypto_buf[0] = htonl(call->call_id);
 	call->crypto_buf[1] = htonl(x);
 
 	sg_init_one(&sg, call->crypto_buf, 8);
@@ -316,12 +314,11 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
 /*
  * decrypt partial encryption on a packet (level 1 security)
  */
-static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
-				    struct sk_buff *skb,
-				    u32 *_abort_code)
+static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
+				 unsigned int offset, unsigned int len,
+				 rxrpc_seq_t seq)
 {
 	struct rxkad_level1_hdr sechdr;
-	struct rxrpc_skb_priv *sp;
 	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
 	struct rxrpc_crypt iv;
 	struct scatterlist sg[16];
@@ -332,15 +329,20 @@ static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
 
 	_enter("");
 
-	sp = rxrpc_skb(skb);
+	if (len < 8) {
+		rxrpc_abort_call("V1H", call, seq, RXKADSEALEDINCON, EPROTO);
+		goto protocol_error;
+	}
 
-	/* we want to decrypt the skbuff in-place */
+	/* Decrypt the skbuff in-place.  TODO: We really want to decrypt
+	 * directly into the target buffer.
+	 */
 	nsg = skb_cow_data(skb, 0, &trailer);
 	if (nsg < 0 || nsg > 16)
 		goto nomem;
 
 	sg_init_table(sg, nsg);
-	skb_to_sgvec(skb, sg, 0, 8);
+	skb_to_sgvec(skb, sg, offset, 8);
 
 	/* start the decryption afresh */
 	memset(&iv, 0, sizeof(iv));
@@ -351,35 +353,35 @@ static int rxkad_verify_packet_auth(const struct rxrpc_call *call,
 	crypto_skcipher_decrypt(req);
 	skcipher_request_zero(req);
 
-	/* remove the decrypted packet length */
-	if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
-		goto datalen_error;
-	if (!skb_pull(skb, sizeof(sechdr)))
-		BUG();
+	/* Extract the decrypted packet length */
+	if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
+		rxrpc_abort_call("XV1", call, seq, RXKADDATALEN, EPROTO);
+		goto protocol_error;
+	}
+	offset += sizeof(sechdr);
+	len -= sizeof(sechdr);
 
 	buf = ntohl(sechdr.data_size);
 	data_size = buf & 0xffff;
 
 	check = buf >> 16;
-	check ^= sp->hdr.seq ^ sp->hdr.callNumber;
+	check ^= seq ^ call->call_id;
 	check &= 0xffff;
 	if (check != 0) {
-		*_abort_code = RXKADSEALEDINCON;
+		rxrpc_abort_call("V1C", call, seq, RXKADSEALEDINCON, EPROTO);
 		goto protocol_error;
 	}
 
-	/* shorten the packet to remove the padding */
-	if (data_size > skb->len)
-		goto datalen_error;
-	else if (data_size < skb->len)
-		skb->len = data_size;
+	if (data_size > len) {
+		rxrpc_abort_call("V1L", call, seq, RXKADDATALEN, EPROTO);
+		goto protocol_error;
+	}
 
 	_leave(" = 0 [dlen=%x]", data_size);
 	return 0;
 
-datalen_error:
-	*_abort_code = RXKADDATALEN;
 protocol_error:
+	rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
 	_leave(" = -EPROTO");
 	return -EPROTO;
 
@@ -391,13 +393,12 @@ nomem:
 /*
  * wholly decrypt a packet (level 2 security)
  */
-static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
-				       struct sk_buff *skb,
-				       u32 *_abort_code)
+static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
+				 unsigned int offset, unsigned int len,
+				 rxrpc_seq_t seq)
 {
 	const struct rxrpc_key_token *token;
 	struct rxkad_level2_hdr sechdr;
-	struct rxrpc_skb_priv *sp;
 	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
 	struct rxrpc_crypt iv;
 	struct scatterlist _sg[4], *sg;
@@ -408,9 +409,14 @@ static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
 
 	_enter(",{%d}", skb->len);
 
-	sp = rxrpc_skb(skb);
+	if (len < 8) {
+		rxrpc_abort_call("V2H", call, seq, RXKADSEALEDINCON, EPROTO);
+		goto protocol_error;
+	}
 
-	/* we want to decrypt the skbuff in-place */
+	/* Decrypt the skbuff in-place.  TODO: We really want to decrypt
+	 * directly into the target buffer.
+	 */
 	nsg = skb_cow_data(skb, 0, &trailer);
 	if (nsg < 0)
 		goto nomem;
@@ -423,7 +429,7 @@ static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
 	}
 
 	sg_init_table(sg, nsg);
-	skb_to_sgvec(skb, sg, 0, skb->len);
+	skb_to_sgvec(skb, sg, offset, len);
 
 	/* decrypt from the session key */
 	token = call->conn->params.key->payload.data[0];
@@ -431,41 +437,41 @@ static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
 
 	skcipher_request_set_tfm(req, call->conn->cipher);
 	skcipher_request_set_callback(req, 0, NULL, NULL);
-	skcipher_request_set_crypt(req, sg, sg, skb->len, iv.x);
+	skcipher_request_set_crypt(req, sg, sg, len, iv.x);
 	crypto_skcipher_decrypt(req);
 	skcipher_request_zero(req);
 	if (sg != _sg)
 		kfree(sg);
 
-	/* remove the decrypted packet length */
-	if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
-		goto datalen_error;
-	if (!skb_pull(skb, sizeof(sechdr)))
-		BUG();
+	/* Extract the decrypted packet length */
+	if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
+		rxrpc_abort_call("XV2", call, seq, RXKADDATALEN, EPROTO);
+		goto protocol_error;
+	}
+	offset += sizeof(sechdr);
+	len -= sizeof(sechdr);
 
 	buf = ntohl(sechdr.data_size);
 	data_size = buf & 0xffff;
 
 	check = buf >> 16;
-	check ^= sp->hdr.seq ^ sp->hdr.callNumber;
+	check ^= seq ^ call->call_id;
 	check &= 0xffff;
 	if (check != 0) {
-		*_abort_code = RXKADSEALEDINCON;
+		rxrpc_abort_call("V2C", call, seq, RXKADSEALEDINCON, EPROTO);
 		goto protocol_error;
 	}
 
-	/* shorten the packet to remove the padding */
-	if (data_size > skb->len)
-		goto datalen_error;
-	else if (data_size < skb->len)
-		skb->len = data_size;
+	if (data_size > len) {
+		rxrpc_abort_call("V2L", call, seq, RXKADDATALEN, EPROTO);
+		goto protocol_error;
+	}
 
 	_leave(" = 0 [dlen=%x]", data_size);
 	return 0;
 
-datalen_error:
-	*_abort_code = RXKADDATALEN;
 protocol_error:
+	rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
 	_leave(" = -EPROTO");
 	return -EPROTO;
 
@@ -475,40 +481,31 @@ nomem:
 }
 
 /*
- * verify the security on a received packet
+ * Verify the security on a received packet or subpacket (if part of a
+ * jumbo packet).
  */
-static int rxkad_verify_packet(struct rxrpc_call *call,
-			       struct sk_buff *skb,
-			       u32 *_abort_code)
+static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			       unsigned int offset, unsigned int len,
+			       rxrpc_seq_t seq, u16 expected_cksum)
 {
 	SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
-	struct rxrpc_skb_priv *sp;
 	struct rxrpc_crypt iv;
 	struct scatterlist sg;
 	u16 cksum;
 	u32 x, y;
-	int ret;
-
-	sp = rxrpc_skb(skb);
 
 	_enter("{%d{%x}},{#%u}",
-	       call->debug_id, key_serial(call->conn->params.key), sp->hdr.seq);
+	       call->debug_id, key_serial(call->conn->params.key), seq);
 
 	if (!call->conn->cipher)
 		return 0;
 
-	if (sp->hdr.securityIndex != RXRPC_SECURITY_RXKAD) {
-		*_abort_code = RXKADINCONSISTENCY;
-		_leave(" = -EPROTO [not rxkad]");
-		return -EPROTO;
-	}
-
 	/* continue encrypting from where we left off */
 	memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
 
 	/* validate the security checksum */
-	x = call->channel << (32 - RXRPC_CIDSHIFT);
-	x |= sp->hdr.seq & 0x3fffffff;
+	x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
+	x |= seq & 0x3fffffff;
 	call->crypto_buf[0] = htonl(call->call_id);
 	call->crypto_buf[1] = htonl(x);
 
@@ -524,29 +521,69 @@ static int rxkad_verify_packet(struct rxrpc_call *call,
 	if (cksum == 0)
 		cksum = 1; /* zero checksums are not permitted */
 
-	if (sp->hdr.cksum != cksum) {
-		*_abort_code = RXKADSEALEDINCON;
+	if (cksum != expected_cksum) {
+		rxrpc_abort_call("VCK", call, seq, RXKADSEALEDINCON, EPROTO);
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
 		_leave(" = -EPROTO [csum failed]");
 		return -EPROTO;
 	}
 
 	switch (call->conn->params.security_level) {
 	case RXRPC_SECURITY_PLAIN:
-		ret = 0;
-		break;
+		return 0;
 	case RXRPC_SECURITY_AUTH:
-		ret = rxkad_verify_packet_auth(call, skb, _abort_code);
-		break;
+		return rxkad_verify_packet_1(call, skb, offset, len, seq);
 	case RXRPC_SECURITY_ENCRYPT:
-		ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
-		break;
+		return rxkad_verify_packet_2(call, skb, offset, len, seq);
 	default:
-		ret = -ENOANO;
-		break;
+		return -ENOANO;
 	}
+}
 
-	_leave(" = %d", ret);
-	return ret;
+/*
+ * Locate the data contained in a packet that was partially encrypted.
+ */
+static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
+				unsigned int *_offset, unsigned int *_len)
+{
+	struct rxkad_level1_hdr sechdr;
+
+	if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
+		BUG();
+	*_offset += sizeof(sechdr);
+	*_len = ntohl(sechdr.data_size) & 0xffff;
+}
+
+/*
+ * Locate the data contained in a packet that was completely encrypted.
+ */
+static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
+				unsigned int *_offset, unsigned int *_len)
+{
+	struct rxkad_level2_hdr sechdr;
+
+	if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
+		BUG();
+	*_offset += sizeof(sechdr);
+	*_len = ntohl(sechdr.data_size) & 0xffff;
+}
+
+/*
+ * Locate the data contained in an already decrypted packet.
+ */
+static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
+			      unsigned int *_offset, unsigned int *_len)
+{
+	switch (call->conn->params.security_level) {
+	case RXRPC_SECURITY_AUTH:
+		rxkad_locate_data_1(call, skb, _offset, _len);
+		return;
+	case RXRPC_SECURITY_ENCRYPT:
+		rxkad_locate_data_2(call, skb, _offset, _len);
+		return;
+	default:
+		return;
+	}
 }
 
 /*
@@ -716,7 +753,7 @@ static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
 	struct rxkad_challenge challenge;
 	struct rxkad_response resp
 		__attribute__((aligned(8))); /* must be aligned for crypto */
-	struct rxrpc_skb_priv *sp;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	u32 version, nonce, min_level, abort_code;
 	int ret;
 
@@ -734,8 +771,8 @@ static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
 	}
 
 	abort_code = RXKADPACKETSHORT;
-	sp = rxrpc_skb(skb);
-	if (skb_copy_bits(skb, 0, &challenge, sizeof(challenge)) < 0)
+	if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+			  &challenge, sizeof(challenge)) < 0)
 		goto protocol_error;
 
 	version = ntohl(challenge.version);
@@ -981,7 +1018,7 @@ static int rxkad_verify_response(struct rxrpc_connection *conn,
 {
 	struct rxkad_response response
 		__attribute__((aligned(8))); /* must be aligned for crypto */
-	struct rxrpc_skb_priv *sp;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct rxrpc_crypt session_key;
 	time_t expiry;
 	void *ticket;
@@ -992,7 +1029,8 @@ static int rxkad_verify_response(struct rxrpc_connection *conn,
 	_enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
 
 	abort_code = RXKADPACKETSHORT;
-	if (skb_copy_bits(skb, 0, &response, sizeof(response)) < 0)
+	if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+			  &response, sizeof(response)) < 0)
 		goto protocol_error;
 	if (!pskb_pull(skb, sizeof(response)))
 		BUG();
@@ -1000,7 +1038,6 @@ static int rxkad_verify_response(struct rxrpc_connection *conn,
 	version = ntohl(response.version);
 	ticket_len = ntohl(response.ticket_len);
 	kvno = ntohl(response.kvno);
-	sp = rxrpc_skb(skb);
 	_proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
 	       sp->hdr.serial, version, kvno, ticket_len);
 
@@ -1022,7 +1059,8 @@ static int rxkad_verify_response(struct rxrpc_connection *conn,
 		return -ENOMEM;
 
 	abort_code = RXKADPACKETSHORT;
-	if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
+	if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+			  ticket, ticket_len) < 0)
 		goto protocol_error_free;
 
 	ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
@@ -1147,6 +1185,7 @@ const struct rxrpc_security rxkad = {
 	.prime_packet_security		= rxkad_prime_packet_security,
 	.secure_packet			= rxkad_secure_packet,
 	.verify_packet			= rxkad_verify_packet,
+	.locate_data			= rxkad_locate_data,
 	.issue_challenge		= rxkad_issue_challenge,
 	.respond_to_challenge		= rxkad_respond_to_challenge,
 	.verify_response		= rxkad_verify_response,
diff --git a/net/rxrpc/security.c b/net/rxrpc/security.c
index 814d285ff802..7d921e56e715 100644
--- a/net/rxrpc/security.c
+++ b/net/rxrpc/security.c
@@ -130,20 +130,20 @@ int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
 	}
 
 	/* find the service */
-	read_lock_bh(&local->services_lock);
-	list_for_each_entry(rx, &local->services, listen_link) {
-		if (rx->srx.srx_service == conn->params.service_id)
-			goto found_service;
-	}
+	read_lock(&local->services_lock);
+	rx = rcu_dereference_protected(local->service,
+				       lockdep_is_held(&local->services_lock));
+	if (rx && rx->srx.srx_service == conn->params.service_id)
+		goto found_service;
 
 	/* the service appears to have died */
-	read_unlock_bh(&local->services_lock);
+	read_unlock(&local->services_lock);
 	_leave(" = -ENOENT");
 	return -ENOENT;
 
 found_service:
 	if (!rx->securities) {
-		read_unlock_bh(&local->services_lock);
+		read_unlock(&local->services_lock);
 		_leave(" = -ENOKEY");
 		return -ENOKEY;
 	}
@@ -152,13 +152,13 @@ found_service:
 	kref = keyring_search(make_key_ref(rx->securities, 1UL),
 			      &key_type_rxrpc_s, kdesc);
 	if (IS_ERR(kref)) {
-		read_unlock_bh(&local->services_lock);
+		read_unlock(&local->services_lock);
 		_leave(" = %ld [search]", PTR_ERR(kref));
 		return PTR_ERR(kref);
 	}
 
 	key = key_ref_to_ptr(kref);
-	read_unlock_bh(&local->services_lock);
+	read_unlock(&local->services_lock);
 
 	conn->server_key = key;
 	conn->security = sec;
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
new file mode 100644
index 000000000000..3322543d460a
--- /dev/null
+++ b/net/rxrpc/sendmsg.c
@@ -0,0 +1,606 @@
+/* AF_RXRPC sendmsg() implementation.
+ *
+ * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/net.h>
+#include <linux/gfp.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+enum rxrpc_command {
+	RXRPC_CMD_SEND_DATA,		/* send data message */
+	RXRPC_CMD_SEND_ABORT,		/* request abort generation */
+	RXRPC_CMD_ACCEPT,		/* [server] accept incoming call */
+	RXRPC_CMD_REJECT_BUSY,		/* [server] reject a call as busy */
+};
+
+/*
+ * wait for space to appear in the transmit/ACK window
+ * - caller holds the socket locked
+ */
+static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
+				    struct rxrpc_call *call,
+				    long *timeo)
+{
+	DECLARE_WAITQUEUE(myself, current);
+	int ret;
+
+	_enter(",{%u,%u,%u}",
+	       call->tx_hard_ack, call->tx_top, call->tx_winsize);
+
+	add_wait_queue(&call->waitq, &myself);
+
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		ret = 0;
+		if (call->tx_top - call->tx_hard_ack <
+		    min_t(unsigned int, call->tx_winsize,
+			  call->cong_cwnd + call->cong_extra))
+			break;
+		if (call->state >= RXRPC_CALL_COMPLETE) {
+			ret = -call->error;
+			break;
+		}
+		if (signal_pending(current)) {
+			ret = sock_intr_errno(*timeo);
+			break;
+		}
+
+		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
+		release_sock(&rx->sk);
+		*timeo = schedule_timeout(*timeo);
+		lock_sock(&rx->sk);
+	}
+
+	remove_wait_queue(&call->waitq, &myself);
+	set_current_state(TASK_RUNNING);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Schedule an instant Tx resend.
+ */
+static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
+{
+	spin_lock_bh(&call->lock);
+
+	if (call->state < RXRPC_CALL_COMPLETE) {
+		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
+		if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
+			rxrpc_queue_call(call);
+	}
+
+	spin_unlock_bh(&call->lock);
+}
+
+/*
+ * Queue a DATA packet for transmission, set the resend timeout and send the
+ * packet immediately
+ */
+static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			       bool last)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	rxrpc_seq_t seq = sp->hdr.seq;
+	int ret, ix;
+	u8 annotation = RXRPC_TX_ANNO_UNACK;
+
+	_net("queue skb %p [%d]", skb, seq);
+
+	ASSERTCMP(seq, ==, call->tx_top + 1);
+
+	if (last)
+		annotation |= RXRPC_TX_ANNO_LAST;
+
+	/* We have to set the timestamp before queueing as the retransmit
+	 * algorithm can see the packet as soon as we queue it.
+	 */
+	skb->tstamp = ktime_get_real();
+
+	ix = seq & RXRPC_RXTX_BUFF_MASK;
+	rxrpc_get_skb(skb, rxrpc_skb_tx_got);
+	call->rxtx_annotations[ix] = annotation;
+	smp_wmb();
+	call->rxtx_buffer[ix] = skb;
+	call->tx_top = seq;
+	if (last)
+		trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
+	else
+		trace_rxrpc_transmit(call, rxrpc_transmit_queue);
+
+	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
+		_debug("________awaiting reply/ACK__________");
+		write_lock_bh(&call->state_lock);
+		switch (call->state) {
+		case RXRPC_CALL_CLIENT_SEND_REQUEST:
+			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
+			break;
+		case RXRPC_CALL_SERVER_ACK_REQUEST:
+			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
+			if (!last)
+				break;
+		case RXRPC_CALL_SERVER_SEND_REPLY:
+			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
+			break;
+		default:
+			break;
+		}
+		write_unlock_bh(&call->state_lock);
+	}
+
+	if (seq == 1 && rxrpc_is_client_call(call))
+		rxrpc_expose_client_call(call);
+
+	ret = rxrpc_send_data_packet(call, skb, false);
+	if (ret < 0) {
+		_debug("need instant resend %d", ret);
+		rxrpc_instant_resend(call, ix);
+	} else {
+		ktime_t now = ktime_get_real(), resend_at;
+
+		resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
+
+		if (ktime_before(resend_at, call->resend_at)) {
+			call->resend_at = resend_at;
+			rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
+		}
+	}
+
+	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+	_leave("");
+}
+
+/*
+ * send data through a socket
+ * - must be called in process context
+ * - caller holds the socket locked
+ */
+static int rxrpc_send_data(struct rxrpc_sock *rx,
+			   struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	struct sock *sk = &rx->sk;
+	long timeo;
+	bool more;
+	int ret, copied;
+
+	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+
+	/* this should be in poll */
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+		return -EPIPE;
+
+	more = msg->msg_flags & MSG_MORE;
+
+	skb = call->tx_pending;
+	call->tx_pending = NULL;
+	rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
+
+	copied = 0;
+	do {
+		/* Check to see if there's a ping ACK to reply to. */
+		if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
+			rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+
+		if (!skb) {
+			size_t size, chunk, max, space;
+
+			_debug("alloc");
+
+			if (call->tx_top - call->tx_hard_ack >=
+			    min_t(unsigned int, call->tx_winsize,
+				  call->cong_cwnd + call->cong_extra)) {
+				ret = -EAGAIN;
+				if (msg->msg_flags & MSG_DONTWAIT)
+					goto maybe_error;
+				ret = rxrpc_wait_for_tx_window(rx, call,
+							       &timeo);
+				if (ret < 0)
+					goto maybe_error;
+			}
+
+			max = RXRPC_JUMBO_DATALEN;
+			max -= call->conn->security_size;
+			max &= ~(call->conn->size_align - 1UL);
+
+			chunk = max;
+			if (chunk > msg_data_left(msg) && !more)
+				chunk = msg_data_left(msg);
+
+			space = chunk + call->conn->size_align;
+			space &= ~(call->conn->size_align - 1UL);
+
+			size = space + call->conn->security_size;
+
+			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
+
+			/* create a buffer that we can retain until it's ACK'd */
+			skb = sock_alloc_send_skb(
+				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
+			if (!skb)
+				goto maybe_error;
+
+			rxrpc_new_skb(skb, rxrpc_skb_tx_new);
+
+			_debug("ALLOC SEND %p", skb);
+
+			ASSERTCMP(skb->mark, ==, 0);
+
+			_debug("HS: %u", call->conn->security_size);
+			skb_reserve(skb, call->conn->security_size);
+			skb->len += call->conn->security_size;
+
+			sp = rxrpc_skb(skb);
+			sp->remain = chunk;
+			if (sp->remain > skb_tailroom(skb))
+				sp->remain = skb_tailroom(skb);
+
+			_net("skb: hr %d, tr %d, hl %d, rm %d",
+			       skb_headroom(skb),
+			       skb_tailroom(skb),
+			       skb_headlen(skb),
+			       sp->remain);
+
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		}
+
+		_debug("append");
+		sp = rxrpc_skb(skb);
+
+		/* append next segment of data to the current buffer */
+		if (msg_data_left(msg) > 0) {
+			int copy = skb_tailroom(skb);
+			ASSERTCMP(copy, >, 0);
+			if (copy > msg_data_left(msg))
+				copy = msg_data_left(msg);
+			if (copy > sp->remain)
+				copy = sp->remain;
+
+			_debug("add");
+			ret = skb_add_data(skb, &msg->msg_iter, copy);
+			_debug("added");
+			if (ret < 0)
+				goto efault;
+			sp->remain -= copy;
+			skb->mark += copy;
+			copied += copy;
+		}
+
+		/* check for the far side aborting the call or a network error
+		 * occurring */
+		if (call->state == RXRPC_CALL_COMPLETE)
+			goto call_terminated;
+
+		/* add the packet to the send queue if it's now full */
+		if (sp->remain <= 0 ||
+		    (msg_data_left(msg) == 0 && !more)) {
+			struct rxrpc_connection *conn = call->conn;
+			uint32_t seq;
+			size_t pad;
+
+			/* pad out if we're using security */
+			if (conn->security_ix) {
+				pad = conn->security_size + skb->mark;
+				pad = conn->size_align - pad;
+				pad &= conn->size_align - 1;
+				_debug("pad %zu", pad);
+				if (pad)
+					memset(skb_put(skb, pad), 0, pad);
+			}
+
+			seq = call->tx_top + 1;
+
+			sp->hdr.seq	= seq;
+			sp->hdr._rsvd	= 0;
+			sp->hdr.flags	= conn->out_clientflag;
+
+			if (msg_data_left(msg) == 0 && !more)
+				sp->hdr.flags |= RXRPC_LAST_PACKET;
+			else if (call->tx_top - call->tx_hard_ack <
+				 call->tx_winsize)
+				sp->hdr.flags |= RXRPC_MORE_PACKETS;
+
+			ret = conn->security->secure_packet(
+				call, skb, skb->mark, skb->head);
+			if (ret < 0)
+				goto out;
+
+			rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
+			skb = NULL;
+		}
+	} while (msg_data_left(msg) > 0);
+
+success:
+	ret = copied;
+out:
+	call->tx_pending = skb;
+	_leave(" = %d", ret);
+	return ret;
+
+call_terminated:
+	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+	_leave(" = %d", -call->error);
+	return -call->error;
+
+maybe_error:
+	if (copied)
+		goto success;
+	goto out;
+
+efault:
+	ret = -EFAULT;
+	goto out;
+}
+
+/*
+ * extract control messages from the sendmsg() control buffer
+ */
+static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
+			      unsigned long *user_call_ID,
+			      enum rxrpc_command *command,
+			      u32 *abort_code,
+			      bool *_exclusive)
+{
+	struct cmsghdr *cmsg;
+	bool got_user_ID = false;
+	int len;
+
+	*command = RXRPC_CMD_SEND_DATA;
+
+	if (msg->msg_controllen == 0)
+		return -EINVAL;
+
+	for_each_cmsghdr(cmsg, msg) {
+		if (!CMSG_OK(msg, cmsg))
+			return -EINVAL;
+
+		len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
+		_debug("CMSG %d, %d, %d",
+		       cmsg->cmsg_level, cmsg->cmsg_type, len);
+
+		if (cmsg->cmsg_level != SOL_RXRPC)
+			continue;
+
+		switch (cmsg->cmsg_type) {
+		case RXRPC_USER_CALL_ID:
+			if (msg->msg_flags & MSG_CMSG_COMPAT) {
+				if (len != sizeof(u32))
+					return -EINVAL;
+				*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
+			} else {
+				if (len != sizeof(unsigned long))
+					return -EINVAL;
+				*user_call_ID = *(unsigned long *)
+					CMSG_DATA(cmsg);
+			}
+			_debug("User Call ID %lx", *user_call_ID);
+			got_user_ID = true;
+			break;
+
+		case RXRPC_ABORT:
+			if (*command != RXRPC_CMD_SEND_DATA)
+				return -EINVAL;
+			*command = RXRPC_CMD_SEND_ABORT;
+			if (len != sizeof(*abort_code))
+				return -EINVAL;
+			*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
+			_debug("Abort %x", *abort_code);
+			if (*abort_code == 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_ACCEPT:
+			if (*command != RXRPC_CMD_SEND_DATA)
+				return -EINVAL;
+			*command = RXRPC_CMD_ACCEPT;
+			if (len != 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_EXCLUSIVE_CALL:
+			*_exclusive = true;
+			if (len != 0)
+				return -EINVAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (!got_user_ID)
+		return -EINVAL;
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * Create a new client call for sendmsg().
+ */
+static struct rxrpc_call *
+rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
+				  unsigned long user_call_ID, bool exclusive)
+{
+	struct rxrpc_conn_parameters cp;
+	struct rxrpc_call *call;
+	struct key *key;
+
+	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
+
+	_enter("");
+
+	if (!msg->msg_name)
+		return ERR_PTR(-EDESTADDRREQ);
+
+	key = rx->key;
+	if (key && !rx->key->payload.data[0])
+		key = NULL;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.local		= rx->local;
+	cp.key			= rx->key;
+	cp.security_level	= rx->min_sec_level;
+	cp.exclusive		= rx->exclusive | exclusive;
+	cp.service_id		= srx->srx_service;
+	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
+
+	_leave(" = %p\n", call);
+	return call;
+}
+
+/*
+ * send a message forming part of a client call through an RxRPC socket
+ * - caller holds the socket locked
+ * - the socket may be either a client socket or a server socket
+ */
+int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
+{
+	enum rxrpc_command cmd;
+	struct rxrpc_call *call;
+	unsigned long user_call_ID = 0;
+	bool exclusive = false;
+	u32 abort_code = 0;
+	int ret;
+
+	_enter("");
+
+	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
+				 &exclusive);
+	if (ret < 0)
+		return ret;
+
+	if (cmd == RXRPC_CMD_ACCEPT) {
+		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
+			return -EINVAL;
+		call = rxrpc_accept_call(rx, user_call_ID, NULL);
+		if (IS_ERR(call))
+			return PTR_ERR(call);
+		rxrpc_put_call(call, rxrpc_call_put);
+		return 0;
+	}
+
+	call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
+	if (!call) {
+		if (cmd != RXRPC_CMD_SEND_DATA)
+			return -EBADSLT;
+		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
+							 exclusive);
+		if (IS_ERR(call))
+			return PTR_ERR(call);
+	}
+
+	_debug("CALL %d USR %lx ST %d on CONN %p",
+	       call->debug_id, call->user_call_ID, call->state, call->conn);
+
+	if (call->state >= RXRPC_CALL_COMPLETE) {
+		/* it's too late for this call */
+		ret = -ESHUTDOWN;
+	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
+		ret = 0;
+		if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
+			ret = rxrpc_send_call_packet(call,
+						     RXRPC_PACKET_TYPE_ABORT);
+	} else if (cmd != RXRPC_CMD_SEND_DATA) {
+		ret = -EINVAL;
+	} else if (rxrpc_is_client_call(call) &&
+		   call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
+		/* request phase complete for this client call */
+		ret = -EPROTO;
+	} else if (rxrpc_is_service_call(call) &&
+		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
+		/* Reply phase not begun or not complete for service call. */
+		ret = -EPROTO;
+	} else {
+		ret = rxrpc_send_data(rx, call, msg, len);
+	}
+
+	rxrpc_put_call(call, rxrpc_call_put);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/**
+ * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
+ * @sock: The socket the call is on
+ * @call: The call to send data through
+ * @msg: The data to send
+ * @len: The amount of data to send
+ *
+ * Allow a kernel service to send data on a call.  The call must be in an state
+ * appropriate to sending data.  No control data should be supplied in @msg,
+ * nor should an address be supplied.  MSG_MORE should be flagged if there's
+ * more data to come, otherwise this data will end the transmission phase.
+ */
+int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len)
+{
+	int ret;
+
+	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
+
+	ASSERTCMP(msg->msg_name, ==, NULL);
+	ASSERTCMP(msg->msg_control, ==, NULL);
+
+	lock_sock(sock->sk);
+
+	_debug("CALL %d USR %lx ST %d on CONN %p",
+	       call->debug_id, call->user_call_ID, call->state, call->conn);
+
+	if (call->state >= RXRPC_CALL_COMPLETE) {
+		ret = -ESHUTDOWN; /* it's too late for this call */
+	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
+		ret = -EPROTO; /* request phase complete for this client call */
+	} else {
+		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
+	}
+
+	release_sock(sock->sk);
+	_leave(" = %d", ret);
+	return ret;
+}
+EXPORT_SYMBOL(rxrpc_kernel_send_data);
+
+/**
+ * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
+ * @sock: The socket the call is on
+ * @call: The call to be aborted
+ * @abort_code: The abort code to stick into the ABORT packet
+ * @error: Local error value
+ * @why: 3-char string indicating why.
+ *
+ * Allow a kernel service to abort a call, if it's still in an abortable state.
+ */
+void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
+			     u32 abort_code, int error, const char *why)
+{
+	_enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
+
+	lock_sock(sock->sk);
+
+	if (rxrpc_abort_call(why, call, 0, abort_code, error))
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
+
+	release_sock(sock->sk);
+	_leave("");
+}
+
+EXPORT_SYMBOL(rxrpc_kernel_abort_call);
diff --git a/net/rxrpc/skbuff.c b/net/rxrpc/skbuff.c
index 06c51d4b622d..67b02c45271b 100644
--- a/net/rxrpc/skbuff.c
+++ b/net/rxrpc/skbuff.c
@@ -18,148 +18,82 @@
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
+#define select_skb_count(op) (op >= rxrpc_skb_tx_cleaned ? &rxrpc_n_tx_skbs : &rxrpc_n_rx_skbs)
+
 /*
- * set up for the ACK at the end of the receive phase when we discard the final
- * receive phase data packet
- * - called with softirqs disabled
+ * Note the allocation or reception of a socket buffer.
  */
-static void rxrpc_request_final_ACK(struct rxrpc_call *call)
+void rxrpc_new_skb(struct sk_buff *skb, enum rxrpc_skb_trace op)
 {
-	/* the call may be aborted before we have a chance to ACK it */
-	write_lock(&call->state_lock);
-
-	switch (call->state) {
-	case RXRPC_CALL_CLIENT_RECV_REPLY:
-		call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
-		_debug("request final ACK");
-
-		/* get an extra ref on the call for the final-ACK generator to
-		 * release */
-		rxrpc_get_call(call);
-		set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
-		if (try_to_del_timer_sync(&call->ack_timer) >= 0)
-			rxrpc_queue_call(call);
-		break;
-
-	case RXRPC_CALL_SERVER_RECV_REQUEST:
-		call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
-	default:
-		break;
-	}
-
-	write_unlock(&call->state_lock);
+	const void *here = __builtin_return_address(0);
+	int n = atomic_inc_return(select_skb_count(op));
+	trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
 }
 
 /*
- * drop the bottom ACK off of the call ACK window and advance the window
+ * Note the re-emergence of a socket buffer from a queue or buffer.
  */
-static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
-				struct rxrpc_skb_priv *sp)
+void rxrpc_see_skb(struct sk_buff *skb, enum rxrpc_skb_trace op)
 {
-	int loop;
-	u32 seq;
-
-	spin_lock_bh(&call->lock);
-
-	_debug("hard ACK #%u", sp->hdr.seq);
-
-	for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
-		call->ackr_window[loop] >>= 1;
-		call->ackr_window[loop] |=
-			call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
-	}
-
-	seq = sp->hdr.seq;
-	ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
-	call->rx_data_eaten = seq;
-
-	if (call->ackr_win_top < UINT_MAX)
-		call->ackr_win_top++;
-
-	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
-		    call->rx_data_post, >=, call->rx_data_recv);
-	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
-		    call->rx_data_recv, >=, call->rx_data_eaten);
-
-	if (sp->hdr.flags & RXRPC_LAST_PACKET) {
-		rxrpc_request_final_ACK(call);
-	} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
-		   test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
-		/* We previously soft-ACK'd some received packets that have now
-		 * been consumed, so send a hard-ACK if no more packets are
-		 * immediately forthcoming to allow the transmitter to free up
-		 * its Tx bufferage.
-		 */
-		_debug("send Rx idle ACK");
-		__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
-				    false);
+	const void *here = __builtin_return_address(0);
+	if (skb) {
+		int n = atomic_read(select_skb_count(op));
+		trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
 	}
-
-	spin_unlock_bh(&call->lock);
 }
 
-/**
- * rxrpc_kernel_data_consumed - Record consumption of data message
- * @call: The call to which the message pertains.
- * @skb: Message holding data
- *
- * Record the consumption of a data message and generate an ACK if appropriate.
- * The call state is shifted if this was the final packet.  The caller must be
- * in process context with no spinlocks held.
- *
- * TODO: Actually generate the ACK here rather than punting this to the
- * workqueue.
+/*
+ * Note the addition of a ref on a socket buffer.
  */
-void rxrpc_kernel_data_consumed(struct rxrpc_call *call, struct sk_buff *skb)
+void rxrpc_get_skb(struct sk_buff *skb, enum rxrpc_skb_trace op)
 {
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-
-	_enter("%d,%p{%u}", call->debug_id, skb, sp->hdr.seq);
-
-	ASSERTCMP(sp->call, ==, call);
-	ASSERTCMP(sp->hdr.type, ==, RXRPC_PACKET_TYPE_DATA);
-
-	/* TODO: Fix the sequence number tracking */
-	ASSERTCMP(sp->hdr.seq, >=, call->rx_data_recv);
-	ASSERTCMP(sp->hdr.seq, <=, call->rx_data_recv + 1);
-	ASSERTCMP(sp->hdr.seq, >, call->rx_data_eaten);
-
-	call->rx_data_recv = sp->hdr.seq;
-	rxrpc_hard_ACK_data(call, sp);
+	const void *here = __builtin_return_address(0);
+	int n = atomic_inc_return(select_skb_count(op));
+	trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
+	skb_get(skb);
 }
-EXPORT_SYMBOL(rxrpc_kernel_data_consumed);
 
 /*
- * Destroy a packet that has an RxRPC control buffer
+ * Note the destruction of a socket buffer.
  */
-void rxrpc_packet_destructor(struct sk_buff *skb)
+void rxrpc_free_skb(struct sk_buff *skb, enum rxrpc_skb_trace op)
 {
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	struct rxrpc_call *call = sp->call;
-
-	_enter("%p{%p}", skb, call);
-
-	if (call) {
-		if (atomic_dec_return(&call->skb_count) < 0)
-			BUG();
-		rxrpc_put_call(call);
-		sp->call = NULL;
+	const void *here = __builtin_return_address(0);
+	if (skb) {
+		int n;
+		CHECK_SLAB_OKAY(&skb->users);
+		n = atomic_dec_return(select_skb_count(op));
+		trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
+		kfree_skb(skb);
 	}
+}
 
-	if (skb->sk)
-		sock_rfree(skb);
-	_leave("");
+/*
+ * Note the injected loss of a socket buffer.
+ */
+void rxrpc_lose_skb(struct sk_buff *skb, enum rxrpc_skb_trace op)
+{
+	const void *here = __builtin_return_address(0);
+	if (skb) {
+		int n;
+		CHECK_SLAB_OKAY(&skb->users);
+		n = atomic_dec_return(select_skb_count(op));
+		trace_rxrpc_skb(skb, op, atomic_read(&skb->users), n, here);
+		kfree_skb(skb);
+	}
 }
 
-/**
- * rxrpc_kernel_free_skb - Free an RxRPC socket buffer
- * @skb: The socket buffer to be freed
- *
- * Let RxRPC free its own socket buffer, permitting it to maintain debug
- * accounting.
+/*
+ * Clear a queue of socket buffers.
  */
-void rxrpc_kernel_free_skb(struct sk_buff *skb)
+void rxrpc_purge_queue(struct sk_buff_head *list)
 {
-	rxrpc_free_skb(skb);
+	const void *here = __builtin_return_address(0);
+	struct sk_buff *skb;
+	while ((skb = skb_dequeue((list))) != NULL) {
+		int n = atomic_dec_return(select_skb_count(rxrpc_skb_rx_purged));
+		trace_rxrpc_skb(skb, rxrpc_skb_rx_purged,
+				atomic_read(&skb->users), n, here);
+		kfree_skb(skb);
+	}
 }
-EXPORT_SYMBOL(rxrpc_kernel_free_skb);
diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
index 03ad08774d4e..34c706d2f79c 100644
--- a/net/rxrpc/sysctl.c
+++ b/net/rxrpc/sysctl.c
@@ -20,7 +20,7 @@ static const unsigned int one = 1;
 static const unsigned int four = 4;
 static const unsigned int thirtytwo = 32;
 static const unsigned int n_65535 = 65535;
-static const unsigned int n_max_acks = RXRPC_MAXACKS;
+static const unsigned int n_max_acks = RXRPC_RXTX_BUFF_SIZE - 1;
 
 /*
  * RxRPC operating parameters.
@@ -35,7 +35,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.data		= &rxrpc_requested_ack_delay,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_ms_jiffies,
+		.proc_handler	= proc_dointvec,
 		.extra1		= (void *)&zero,
 	},
 	{
@@ -43,7 +43,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.data		= &rxrpc_soft_ack_delay,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_ms_jiffies,
+		.proc_handler	= proc_dointvec,
 		.extra1		= (void *)&one,
 	},
 	{
@@ -51,7 +51,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.data		= &rxrpc_idle_ack_delay,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_ms_jiffies,
+		.proc_handler	= proc_dointvec,
 		.extra1		= (void *)&one,
 	},
 	{
@@ -59,6 +59,22 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.data		= &rxrpc_resend_timeout,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= (void *)&one,
+	},
+	{
+		.procname	= "idle_conn_expiry",
+		.data		= &rxrpc_conn_idle_client_expiry,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_ms_jiffies,
+		.extra1		= (void *)&one,
+	},
+	{
+		.procname	= "idle_conn_fast_expiry",
+		.data		= &rxrpc_conn_idle_client_fast_expiry,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
 		.proc_handler	= proc_dointvec_ms_jiffies,
 		.extra1		= (void *)&one,
 	},
@@ -69,29 +85,28 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.data		= &rxrpc_max_call_lifetime,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_jiffies,
+		.proc_handler	= proc_dointvec,
 		.extra1		= (void *)&one,
 	},
+
+	/* Non-time values */
 	{
-		.procname	= "dead_call_expiry",
-		.data		= &rxrpc_dead_call_expiry,
+		.procname	= "max_client_conns",
+		.data		= &rxrpc_max_client_connections,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_jiffies,
-		.extra1		= (void *)&one,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)&rxrpc_reap_client_connections,
 	},
-
-	/* Values measured in seconds */
 	{
-		.procname	= "connection_expiry",
-		.data		= &rxrpc_connection_expiry,
+		.procname	= "reap_client_conns",
+		.data		= &rxrpc_reap_client_connections,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= (void *)&one,
+		.extra2		= (void *)&rxrpc_max_client_connections,
 	},
-
-	/* Non-time values */
 	{
 		.procname	= "max_backlog",
 		.data		= &rxrpc_max_backlog,
diff --git a/net/rxrpc/utils.c b/net/rxrpc/utils.c
index b88914d53ca5..ff7af71c4b49 100644
--- a/net/rxrpc/utils.c
+++ b/net/rxrpc/utils.c
@@ -30,6 +30,7 @@ int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *srx, struct sk_buff *skb)
 		srx->transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 		return 0;
 
+#ifdef CONFIG_AF_RXRPC_IPV6
 	case ETH_P_IPV6:
 		srx->transport_type = SOCK_DGRAM;
 		srx->transport_len = sizeof(srx->transport.sin6);
@@ -37,6 +38,7 @@ int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *srx, struct sk_buff *skb)
 		srx->transport.sin6.sin6_port = udp_hdr(skb)->source;
 		srx->transport.sin6.sin6_addr = ipv6_hdr(skb)->saddr;
 		return 0;
+#endif
 
 	default:
 		pr_warn_ratelimited("AF_RXRPC: Unknown eth protocol %u\n",