tipc: fix hanging clients using poll with EPOLLOUT flag

[ Upstream commit ff946833b70e0c7f93de9a3f5b329b5ae2287b38 ]

commit 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets")
introduced a regression for clients using non-blocking sockets.
After the commit, we send EPOLLOUT event to the client even in
TIPC_CONNECTING state. This causes the subsequent send() to fail
with ENOTCONN, as the socket is still not in TIPC_ESTABLISHED state.

In this commit, we:
- improve the fix for hanging poll() by replacing sk_data_ready()
  with sk_state_change() to wake up all clients.
- revert the faulty updates introduced by commit 517d7c79bdb398
  ("tipc: fix hanging poll() for stream sockets").

Fixes: 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets")
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@gmail.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 67a7b31..6c91f12 100644 (file)
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -726,11 +726,11 @@ static __poll_t tipc_poll(struct file *file, struct socket *sock,
 
        switch (sk->sk_state) {
        case TIPC_ESTABLISHED:
-       case TIPC_CONNECTING:
                if (!tsk->cong_link_cnt && !tsk_conn_cong(tsk))
                        revents |= EPOLLOUT;
                /* fall thru' */
        case TIPC_LISTEN:
+       case TIPC_CONNECTING:
                if (!skb_queue_empty(&sk->sk_receive_queue))
                        revents |= EPOLLIN | EPOLLRDNORM;
                break;
@@ -2039,7 +2039,7 @@ static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
                        return true;
 
                /* If empty 'ACK-' message, wake up sleeping connect() */
-               sk->sk_data_ready(sk);
+               sk->sk_state_change(sk);
 
                /* 'ACK-' message is neither accepted nor rejected: */
                msg_set_dest_droppable(hdr, 1);