af_iucv: avoid path quiesce of severed path in shutdown()

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index d79f5fb..a089b6b 100644 (file)
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1542,7 +1542,8 @@ static int iucv_sock_shutdown(struct socket *sock, int how)
 
        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;