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/ipv4/af_inet.c b/net/ipv4/af_inet.c
index c5376c7..5ca7290 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -548,7 +548,7 @@
 {
 	DEFINE_WAIT(wait);
 
-	prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 
 	/* Basic assumption: if someone sets sk->sk_err, he _must_
 	 * change state of the socket from TCP_SYN_*.
@@ -561,9 +561,9 @@
 		lock_sock(sk);
 		if (signal_pending(current) || !timeo)
 			break;
-		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	}
-	finish_wait(sk->sk_sleep, &wait);
+	finish_wait(sk_sleep(sk), &wait);
 	return timeo;
 }
 
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 8da6429..e0a3e35 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -234,7 +234,7 @@
 	 * having to remove and re-insert us on the wait queue.
 	 */
 	for (;;) {
-		prepare_to_wait_exclusive(sk->sk_sleep, &wait,
+		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
 					  TASK_INTERRUPTIBLE);
 		release_sock(sk);
 		if (reqsk_queue_empty(&icsk->icsk_accept_queue))
@@ -253,7 +253,7 @@
 		if (!timeo)
 			break;
 	}
-	finish_wait(sk->sk_sleep, &wait);
+	finish_wait(sk_sleep(sk), &wait);
 	return err;
 }
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0f8caf6..7720833 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -378,7 +378,7 @@
 	struct sock *sk = sock->sk;
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	sock_poll_wait(file, sk->sk_sleep, wait);
+	sock_poll_wait(file, sk_sleep(sk), wait);
 	if (sk->sk_state == TCP_LISTEN)
 		return inet_csk_listen_poll(sk);