[PATCH 5.10 075/103] tipc: call tipc_wait_for_connect only when dlen is not 0

[Greg Kroah-Hartman]

From: Xin Long <lucien.xin@xxxxxxxxx>

commit 7387a72c5f84f0dfb57618f9e4770672c0d2e4c9 upstream.

__tipc_sendmsg() is called to send SYN packet by either tipc_sendmsg()
or tipc_connect(). The difference is in tipc_connect(), it will call
tipc_wait_for_connect() after __tipc_sendmsg() to wait until connecting
is done. So there's no need to wait in __tipc_sendmsg() for this case.

This patch is to fix it by calling tipc_wait_for_connect() only when dlen
is not 0 in __tipc_sendmsg(), which means it's called by tipc_connect().

Note this also fixes the failure in tipcutils/test/ptts/:

  # ./tipcTS &
  # ./tipcTC 9
  (hang)

Fixes: 36239dab6da7 ("tipc: fix implicit-connect for SYN+")
Reported-by: Shuang Li <shuali@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/tipc/socket.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1511,7 +1511,7 @@ static int __tipc_sendmsg(struct socket
 
 	if (unlikely(syn && !rc)) {
 		tipc_set_sk_state(sk, TIPC_CONNECTING);
-		if (timeout) {
+		if (dlen && timeout) {
 			timeout = msecs_to_jiffies(timeout);
 			tipc_wait_for_connect(sock, &timeout);
 		}