[patch 2/2] af_iucv: avoid path quiesce of severed path in shutdown()

[frank.blaschka@de.ibm.com]

[-- Attachment #1: 601-af_iucv-path-quiesce.diff --]
[-- Type: text/plain, Size: 1092 bytes --]

From: Ursula Braun <ursula.braun@de.ibm.com>

An af_iucv stress test showed -EPIPE results for sendmsg()
calls. They are caused by quiescing a path even though it has
been already severed by peer. For IUCV transport shutdown()
consists of 2 steps:
(1) sending the shutdown message to peer
(2) quiescing the iucv path
If the iucv path between these 2 steps is severed due to peer
closing the path, the quiesce step is no longer needed.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Reported-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
---
 net/iucv/af_iucv.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1542,7 +1542,8 @@ static int iucv_sock_shutdown(struct soc
 
 	sk->sk_shutdown |= how;
 	if (how == RCV_SHUTDOWN || how == SHUTDOWN_MASK) {
-		if (iucv->transport == AF_IUCV_TRANS_IUCV) {
+		if ((iucv->transport == AF_IUCV_TRANS_IUCV) &&
+		    iucv->path) {
 			err = pr_iucv->path_quiesce(iucv->path, NULL);
 			if (err)
 				err = -ENOTCONN;