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/atm/signaling.c b/net/atm/signaling.c
index 6ba6e46..509c8ac 100644
--- a/net/atm/signaling.c
+++ b/net/atm/signaling.c
@@ -131,7 +131,7 @@
 		}
 		sk->sk_ack_backlog++;
 		skb_queue_tail(&sk->sk_receive_queue, skb);
-		pr_debug("waking sk->sk_sleep 0x%p\n", sk->sk_sleep);
+		pr_debug("waking sk_sleep(sk) 0x%p\n", sk_sleep(sk));
 		sk->sk_state_change(sk);
 as_indicate_complete:
 		release_sock(sk);