Merge branch 'master' into for-4.4-fixes

The following commit which went into mainline through networking tree

  3b13758f51de ("cgroups: Allow dynamically changing net_classid")

conflicts in net/core/netclassid_cgroup.c with the following pending
fix in cgroup/for-4.4-fixes.

  1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration from subtree_control enabling")

The former separates out update_classid() from cgrp_attach() and
updates it to walk all fds of all tasks in the target css so that it
can be used from both migration and config change paths.  The latter
drops @css from cgrp_attach().

Resolve the conflict by making cgrp_attach() call update_classid()
with the css from the first task.  We can revive @tset walking in
cgrp_attach() but given that net_cls is v1 only where there always is
only one target css during migration, this is fine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Nina Schiff <ninasc@fb.com>

1 files changed, 50 insertions, 7 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index bbf7c2cf15b4..52d27ee924f4 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -254,7 +254,6 @@ struct cg_proto;
   *	@sk_wq: sock wait queue and async head
   *	@sk_rx_dst: receive input route used by early demux
   *	@sk_dst_cache: destination cache
-  *	@sk_dst_lock: destination cache lock
   *	@sk_policy: flow policy
   *	@sk_receive_queue: incoming packets
   *	@sk_wmem_alloc: transmit queue bytes committed
@@ -384,14 +383,16 @@ struct sock {
 	int			sk_rcvbuf;
 
 	struct sk_filter __rcu	*sk_filter;
-	struct socket_wq __rcu	*sk_wq;
-
+	union {
+		struct socket_wq __rcu	*sk_wq;
+		struct socket_wq	*sk_wq_raw;
+	};
 #ifdef CONFIG_XFRM
 	struct xfrm_policy	*sk_policy[2];
 #endif
 	struct dst_entry	*sk_rx_dst;
 	struct dst_entry __rcu	*sk_dst_cache;
-	spinlock_t		sk_dst_lock;
+	/* Note: 32bit hole on 64bit arches */
 	atomic_t		sk_wmem_alloc;
 	atomic_t		sk_omem_alloc;
 	int			sk_sndbuf;
@@ -2005,10 +2006,27 @@ static inline unsigned long sock_wspace(struct sock *sk)
 	return amt;
 }
 
-static inline void sk_wake_async(struct sock *sk, int how, int band)
+/* Note:
+ *  We use sk->sk_wq_raw, from contexts knowing this
+ *  pointer is not NULL and cannot disappear/change.
+ */
+static inline void sk_set_bit(int nr, struct sock *sk)
+{
+	set_bit(nr, &sk->sk_wq_raw->flags);
+}
+
+static inline void sk_clear_bit(int nr, struct sock *sk)
+{
+	clear_bit(nr, &sk->sk_wq_raw->flags);
+}
+
+static inline void sk_wake_async(const struct sock *sk, int how, int band)
 {
-	if (sock_flag(sk, SOCK_FASYNC))
-		sock_wake_async(sk->sk_socket, how, band);
+	if (sock_flag(sk, SOCK_FASYNC)) {
+		rcu_read_lock();
+		sock_wake_async(rcu_dereference(sk->sk_wq), how, band);
+		rcu_read_unlock();
+	}
 }
 
 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
@@ -2226,6 +2244,31 @@ static inline bool sk_listener(const struct sock *sk)
 	return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
 }
 
+/**
+ * sk_state_load - read sk->sk_state for lockless contexts
+ * @sk: socket pointer
+ *
+ * Paired with sk_state_store(). Used in places we do not hold socket lock :
+ * tcp_diag_get_info(), tcp_get_info(), tcp_poll(), get_tcp4_sock() ...
+ */
+static inline int sk_state_load(const struct sock *sk)
+{
+	return smp_load_acquire(&sk->sk_state);
+}
+
+/**
+ * sk_state_store - update sk->sk_state
+ * @sk: socket pointer
+ * @newstate: new state
+ *
+ * Paired with sk_state_load(). Should be used in contexts where
+ * state change might impact lockless readers.
+ */
+static inline void sk_state_store(struct sock *sk, int newstate)
+{
+	smp_store_release(&sk->sk_state, newstate);
+}
+
 void sock_enable_timestamp(struct sock *sk, int flag);
 int sock_get_timestamp(struct sock *, struct timeval __user *);
 int sock_get_timestampns(struct sock *, struct timespec __user *);