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/common.c b/net/atm/common.c
index 97ed94a..e3e10e6 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -92,7 +92,7 @@
 {
 	read_lock(&sk->sk_callback_lock);
 	if (sk_has_sleeper(sk))
-		wake_up(sk->sk_sleep);
+		wake_up(sk_sleep(sk));
 	read_unlock(&sk->sk_callback_lock);
 }
 
@@ -110,7 +110,7 @@
 
 	if (vcc_writable(sk)) {
 		if (sk_has_sleeper(sk))
-			wake_up_interruptible(sk->sk_sleep);
+			wake_up_interruptible(sk_sleep(sk));
 
 		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 	}
@@ -549,7 +549,7 @@
 	}
 
 	eff = (size+3) & ~3; /* align to word boundary */
-	prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	error = 0;
 	while (!(skb = alloc_tx(vcc, eff))) {
 		if (m->msg_flags & MSG_DONTWAIT) {
@@ -568,9 +568,9 @@
 			send_sig(SIGPIPE, current, 0);
 			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);
 	if (error)
 		goto out;
 	skb->dev = NULL; /* for paths shared with net_device interfaces */
@@ -595,7 +595,7 @@
 	struct atm_vcc *vcc;
 	unsigned int mask;
 
-	sock_poll_wait(file, sk->sk_sleep, wait);
+	sock_poll_wait(file, sk_sleep(sk), wait);
 	mask = 0;
 
 	vcc = ATM_SD(sock);