sock: Introduce named constants for sk_reuse

Name them in a "backward compatible" manner, i.e. reuse or not
are still 1 and 0 respectively. The reuse value of 2 means that
the socket with it will forcibly reuse everyone else's port.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index 044e7b5..1bfe880 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -2005,7 +2005,7 @@
 	o2net_listen_sock = sock;
 	INIT_WORK(&o2net_listen_work, o2net_accept_many);
 
-	sock->sk->sk_reuse = 1;
+	sock->sk->sk_reuse = SK_CAN_REUSE;
 	ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
 	if (ret < 0) {
 		printk(KERN_ERR "o2net: Error %d while binding socket at "