iw_cxgb4: drop listen destroy replies if no ep found

If the thread waiting for a CLOSE_LISTSRV_RPL times out and bails,
then we need to handle a subsequent CPL if it arrives and the stid has
been released.  In this case silently drop it.

Cc: stable@vger.kernel.org
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

drivers/infiniband/hw/cxgb4/cm.c

@@ -2333,9 +2333,14 @@ static int close_listsrv_rpl(struct c4iw_dev *dev, struct sk_buff *skb)
 	unsigned int stid = GET_TID(rpl);
 	struct c4iw_listen_ep *ep = get_ep_from_stid(dev, stid);
 
+	if (!ep) {
+		pr_debug("%s stid %d lookup failure!\n", __func__, stid);
+		goto out;
+	}
 	pr_debug("%s ep %p\n", __func__, ep);
 	c4iw_wake_up(&ep->com.wr_wait, status2errno(rpl->status));
 	c4iw_put_ep(&ep->com);
+out:
 	return 0;
 }