rxrpc: Add notification of end-of-Tx phase

Add a callback to rxrpc_kernel_send_data() so that a kernel service can get
a notification that the AF_RXRPC call has transitioned out the Tx phase and
is now waiting for a reply or a final ACK.

This is called from AF_RXRPC with the call state lock held so the
notification is guaranteed to come before any reply is passed back.

Further, modify the AFS filesystem to make use of this so that we don't have
to change the afs_call state before sending the last bit of data.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 35 insertions, 11 deletions

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 10743043d431..0bf191f0dbaf 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -292,6 +292,19 @@ static void afs_load_bvec(struct afs_call *call, struct msghdr *msg,
 }
 
 /*
+ * Advance the AFS call state when the RxRPC call ends the transmit phase.
+ */
+static void afs_notify_end_request_tx(struct sock *sock,
+				      struct rxrpc_call *rxcall,
+				      unsigned long call_user_ID)
+{
+	struct afs_call *call = (struct afs_call *)call_user_ID;
+
+	if (call->state == AFS_CALL_REQUESTING)
+		call->state = AFS_CALL_AWAIT_REPLY;
+}
+
+/*
  * attach the data from a bunch of pages on an inode to a call
  */
 static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
@@ -310,14 +323,8 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
 		bytes = msg->msg_iter.count;
 		nr = msg->msg_iter.nr_segs;
 
-		/* Have to change the state *before* sending the last
-		 * packet as RxRPC might give us the reply before it
-		 * returns from sending the request.
-		 */
-		if (first + nr - 1 >= last)
-			call->state = AFS_CALL_AWAIT_REPLY;
-		ret = rxrpc_kernel_send_data(afs_socket, call->rxcall,
-					     msg, bytes);
+		ret = rxrpc_kernel_send_data(afs_socket, call->rxcall, msg,
+					     bytes, afs_notify_end_request_tx);
 		for (loop = 0; loop < nr; loop++)
 			put_page(bv[loop].bv_page);
 		if (ret < 0)
@@ -409,7 +416,8 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 	if (!call->send_pages)
 		call->state = AFS_CALL_AWAIT_REPLY;
 	ret = rxrpc_kernel_send_data(afs_socket, rxcall,
-				     &msg, call->request_size);
+				     &msg, call->request_size,
+				     afs_notify_end_request_tx);
 	if (ret < 0)
 		goto error_do_abort;
 
@@ -741,6 +749,20 @@ static int afs_deliver_cm_op_id(struct afs_call *call)
 }
 
 /*
+ * Advance the AFS call state when an RxRPC service call ends the transmit
+ * phase.
+ */
+static void afs_notify_end_reply_tx(struct sock *sock,
+				    struct rxrpc_call *rxcall,
+				    unsigned long call_user_ID)
+{
+	struct afs_call *call = (struct afs_call *)call_user_ID;
+
+	if (call->state == AFS_CALL_REPLYING)
+		call->state = AFS_CALL_AWAIT_ACK;
+}
+
+/*
  * send an empty reply
  */
 void afs_send_empty_reply(struct afs_call *call)
@@ -759,7 +781,8 @@ void afs_send_empty_reply(struct afs_call *call)
 	msg.msg_flags		= 0;
 
 	call->state = AFS_CALL_AWAIT_ACK;
-	switch (rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, 0)) {
+	switch (rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, 0,
+				       afs_notify_end_reply_tx)) {
 	case 0:
 		_leave(" [replied]");
 		return;
@@ -797,7 +820,8 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 	msg.msg_flags		= 0;
 
 	call->state = AFS_CALL_AWAIT_ACK;
-	n = rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, len);
+	n = rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, len,
+				   afs_notify_end_reply_tx);
 	if (n >= 0) {
 		/* Success */
 		_leave(" [replied]");