[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/socket.c b/net/socket.c
index aeeab38..9ebca5c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1070,20 +1070,19 @@
 	if (!sock || !sock->fasync_list)
 		return -1;
 	switch (how) {
-	case 1:
-
+	case SOCK_WAKE_WAITD:
 		if (test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
 			break;
 		goto call_kill;
-	case 2:
+	case SOCK_WAKE_SPACE:
 		if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags))
 			break;
 		/* fall through */
-	case 0:
+	case SOCK_WAKE_IO:
 call_kill:
 		__kill_fasync(sock->fasync_list, SIGIO, band);
 		break;
-	case 3:
+	case SOCK_WAKE_URG:
 		__kill_fasync(sock->fasync_list, SIGURG, band);
 	}
 	return 0;