From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Thu, 3 Apr 2008 15:38:39 +0200
Subject: [s390] zfcp: hold lock on port handle for ELS command
Message-id: 20080403133839.GG10542@redhat.com
O-Subject: [RHEL5 U3 PATCH 5/7] s390 - zfcp: Hold queue lock when checking port handle for ELS command
Bugzilla: 434955
RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com>

Description
============

We need to hold the queue-lock when checking whether we still have a valid port
handle for the ELS command, i.e whether we can issue this request for this
port. If the error recovery is about to close this port, then it competes for
the queue-lock. If the close request issued by the error recovery wins, then it
is guaranteed that this port has been blocked for other requests.

Bugzilla
=========

BZ 434955
https://bugzilla.redhat.com/show_bug.cgi?id=434955

Upstream status of the patch:
=============================

Patch included in linux-2.6 as git commit
3f0ca62add34010241db682e63bb68ba765bf4a9

Test status:
============
Kernel with patch was built and successfully tested

Please ACK.

With best regards,

Hans

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 3a3f30b..6cc091b 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -457,7 +457,7 @@ zfcp_test_link(struct zfcp_port *port)
 
 	zfcp_port_get(port);
 	retval = zfcp_erp_adisc(port);
-	if (retval != 0) {
+	if (retval != 0 && retval != -EBUSY) {
 		zfcp_port_put(port);
 		ZFCP_LOG_NORMAL("reopen needed for port 0x%016Lx "
 				"on adapter %s\n ", port->wwpn,
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 92ed66f..9e160f4 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -1670,6 +1670,12 @@ zfcp_fsf_send_els(struct zfcp_send_els *els)
                 goto failed_req;
 	}
 
+	if (unlikely(!atomic_test_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
+			&els->port->status))) {
+		ret = -EBUSY;
+		goto port_blocked;
+	}
+
 	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
         if (zfcp_use_one_sbal(els->req, els->req_count,
                               els->resp, els->resp_count)){
@@ -1751,6 +1757,7 @@ zfcp_fsf_send_els(struct zfcp_send_els *els)
 		       "0x%08x)\n", zfcp_get_busid_by_adapter(adapter), d_id);
 	goto out;
 
+ port_blocked:
  failed_send:
 	zfcp_fsf_req_free(fsf_req);