tipc: fix inconsistent signal handling regression

Commit 9bbb4ec ("tipc: standardize recvmsg routine") changed
the sleep/wakeup behaviour for sockets entering recv() or accept().
In this process the order of reporting -EAGAIN/-EINTR was reversed.
This caused problems with wrong errno being reported back if the
timeout expires. The same problem happens if the socket is
nonblocking and recv()/accept() is called when the process have
pending signals. If there is no pending data read or connections to
accept, -EINTR will be returned instead of -EAGAIN.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Reported-by László Benedek <laszlo.benedek@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/socket.c

@@ -1318,12 +1318,12 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
 		err = 0;
 		if (!skb_queue_empty(&sk->sk_receive_queue))
 			break;
-		err = sock_intr_errno(timeo);
-		if (signal_pending(current))
-			break;
 		err = -EAGAIN;
 		if (!timeo)
 			break;
+		err = sock_intr_errno(timeo);
+		if (signal_pending(current))
+			break;
 	}
 	finish_wait(sk_sleep(sk), &wait);
 	*timeop = timeo;
@@ -2026,12 +2026,12 @@ static int tipc_wait_for_accept(struct socket *sock, long timeo)
 		err = -EINVAL;
 		if (sock->state != SS_LISTENING)
 			break;
-		err = sock_intr_errno(timeo);
-		if (signal_pending(current))
-			break;
 		err = -EAGAIN;
 		if (!timeo)
 			break;
+		err = sock_intr_errno(timeo);
+		if (signal_pending(current))
+			break;
 	}
 	finish_wait(sk_sleep(sk), &wait);
 	return err;