tipc: Fix missing connection request handling

In filter_connect, we use waitqueue_active() to check for any
connections to wakeup. But waitqueue_active() is missing memory
barriers while accessing the critical sections, leading to
inconsistent results.

In this commit, we replace this with an SMP safe wq_has_sleeper()
using the generic socket callback sk_data_ready().

Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/socket.c

@@ -1581,8 +1581,7 @@ static bool filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
 			return true;
 
 		/* If empty 'ACK-' message, wake up sleeping connect() */
-		if (waitqueue_active(sk_sleep(sk)))
-			wake_up_interruptible(sk_sleep(sk));
+		sk->sk_data_ready(sk);
 
 		/* 'ACK-' message is neither accepted nor rejected: */
 		msg_set_dest_droppable(hdr, 1);