net: sk_sleep() helper

Define a new function to return the waitqueue of a "struct sock".

static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
	return sk->sk_sleep;
}

Change all read occurrences of sk_sleep by a call to this function.

Needed for a future RCU conversion. sk_sleep wont be a field directly
available.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 3d9122e..87c0360 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -316,7 +316,7 @@
 	read_lock(&sk->sk_callback_lock);
 	if (unix_writable(sk)) {
 		if (sk_has_sleeper(sk))
-			wake_up_interruptible_sync(sk->sk_sleep);
+			wake_up_interruptible_sync(sk_sleep(sk));
 		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 	}
 	read_unlock(&sk->sk_callback_lock);
@@ -1736,7 +1736,7 @@
 	unix_state_lock(sk);
 
 	for (;;) {
-		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 
 		if (!skb_queue_empty(&sk->sk_receive_queue) ||
 		    sk->sk_err ||
@@ -1752,7 +1752,7 @@
 		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 	}
 
-	finish_wait(sk->sk_sleep, &wait);
+	finish_wait(sk_sleep(sk), &wait);
 	unix_state_unlock(sk);
 	return timeo;
 }
@@ -1991,7 +1991,7 @@
 	struct sock *sk = sock->sk;
 	unsigned int mask;
 
-	sock_poll_wait(file, sk->sk_sleep, wait);
+	sock_poll_wait(file, sk_sleep(sk), wait);
 	mask = 0;
 
 	/* exceptional events? */
@@ -2028,7 +2028,7 @@
 	struct sock *sk = sock->sk, *other;
 	unsigned int mask, writable;
 
-	sock_poll_wait(file, sk->sk_sleep, wait);
+	sock_poll_wait(file, sk_sleep(sk), wait);
 	mask = 0;
 
 	/* exceptional events? */