[NET]: Name magic constants in sock_wake_async()

The sock_wake_async() performs a bit different actions
depending on "how" argument. Unfortunately this argument
ony has numerical magic values.

I propose to give names to their constants to help people
reading this function callers understand what's going on
without looking into this function all the time.

I suppose this is 2.6.25 material, but if it's not (or the
naming seems poor/bad/awful), I can rework it against the
current net-2.6 tree.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 79996b1..97ea3ed 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3595,9 +3595,9 @@
 		/* Do not send POLL_HUP for half duplex close. */
 		if (sk->sk_shutdown == SHUTDOWN_MASK ||
 		    sk->sk_state == TCP_CLOSE)
-			sk_wake_async(sk, 1, POLL_HUP);
+			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
 		else
-			sk_wake_async(sk, 1, POLL_IN);
+			sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
 	}
 }
 
@@ -4956,7 +4956,7 @@
 
 		if (!sock_flag(sk, SOCK_DEAD)) {
 			sk->sk_state_change(sk);
-			sk_wake_async(sk, 0, POLL_OUT);
+			sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
 		}
 
 		if (sk->sk_write_pending ||
@@ -5186,9 +5186,9 @@
 				 * are not waked up, because sk->sk_sleep ==
 				 * NULL and sk->sk_socket == NULL.
 				 */
-				if (sk->sk_socket) {
-					sk_wake_async(sk,0,POLL_OUT);
-				}
+				if (sk->sk_socket)
+					sk_wake_async(sk,
+							SOCK_WAKE_IO, POLL_OUT);
 
 				tp->snd_una = TCP_SKB_CB(skb)->ack_seq;
 				tp->snd_wnd = ntohs(th->window) <<