static int tipc_wait_for_accept(struct socket *sock, long timeo)
{
	struct sock *sk = sock->sk;
	DEFINE_WAIT(wait);
	int err;

	/* True wake-one mechanism for incoming connections: only
	 * one process gets woken up, not the 'whole herd'.
	 * Since we do not 'race & poll' for established sockets
	 * anymore, the common case will execute the loop only once.
	*/
	for (;;) {
		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
					  TASK_INTERRUPTIBLE);
		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
			release_sock(sk);
			timeo = schedule_timeout(timeo);
			lock_sock(sk);
		}
		err = 0;
		if (!skb_queue_empty(&sk->sk_receive_queue))
			break;
		err = -EINVAL;
		if (sock->state != SS_LISTENING)
			break;
		err = -EAGAIN;
		if (!timeo)
			break;
		err = sock_intr_errno(timeo);
		if (signal_pending(current))
			break;
	}
	finish_wait(sk_sleep(sk), &wait);
	return err;
}

Unknown