From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Thu, 3 Apr 2008 15:37:24 +0200
Subject: [s390] zfcp: hold lock when checking port/unit handle
Message-id: 20080403133724.GE10542@redhat.com
O-Subject: [RHEL5 U3 PATCH 3/7] s390 - zfcp: Hold queue lock when checking port/unit handle for abort command
Bugzilla: 434953
RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com>

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

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

Bugzilla
=========

BZ 434953
https://bugzilla.redhat.com/show_bug.cgi?id=434953

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

Patch included in linux-2.6 as git commit 951f746fece2e24a26853b3872d16e9013b6fe0b

Test status:
============

Kernel with patch was built and successfully tested

Please ACK.

With best regards,

Hans

 drivers/s390/scsi/zfcp_fsf.c |   23 +++++++++--------------
 1 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index e26f607..59edf96 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -1117,6 +1117,10 @@ zfcp_fsf_abort_fcp_command(unsigned long old_req_id,
 		goto out;
 	}
 
+	if (unlikely(!atomic_test_mask(ZFCP_STATUS_COMMON_UNBLOCKED,
+			&unit->status)))
+		goto unit_blocked;
+
 	sbale = zfcp_qdio_sbale_req(fsf_req, fsf_req->sbal_curr, 0);
         sbale[0].flags |= SBAL_FLAGS0_TYPE_READ;
         sbale[1].flags |= SBAL_FLAGS_LAST_ENTRY;
@@ -1132,22 +1136,13 @@ zfcp_fsf_abort_fcp_command(unsigned long old_req_id,
 
 	zfcp_fsf_start_timer(fsf_req, ZFCP_SCSI_ER_TIMEOUT);
 	retval = zfcp_fsf_req_send(fsf_req);
-	if (retval) {
-		ZFCP_LOG_INFO("error: Failed to send abort command request "
-			      "on adapter %s, port 0x%016Lx, unit 0x%016Lx\n",
-			      zfcp_get_busid_by_adapter(adapter),
-			      unit->port->wwpn, unit->fcp_lun);
-		zfcp_fsf_req_free(fsf_req);
-		fsf_req = NULL;
+	if (!retval)
 		goto out;
-	}
 
-	ZFCP_LOG_DEBUG("Abort FCP Command request initiated "
-		       "(adapter%s, port d_id=0x%08x, "
-		       "unit x%016Lx, old_req_id=0x%lx)\n",
-		       zfcp_get_busid_by_adapter(adapter),
-		       unit->port->d_id,
-		       unit->fcp_lun, old_req_id);
+ unit_blocked:
+	zfcp_fsf_req_free(fsf_req);
+	fsf_req = NULL;
+
  out:
 	write_unlock_irqrestore(&adapter->request_queue.queue_lock, lock_flags);
 	return fsf_req;