[ 3.5.y.z extended stable ] Patch "[SCSI] isci: Fix a race condition in the SSP task management" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    [SCSI] isci: Fix a race condition in the SSP task management

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ada7526b94567abaea07101a0dd63e0a6ca6fc9a Mon Sep 17 00:00:00 2001
From: Jeff Skirvin <jeffrey.d.skirvin at intel.com>
Date: Thu, 11 Jul 2013 17:18:58 -0700
Subject: [PATCH] [SCSI] isci: Fix a race condition in the SSP task management
 path

commit 96f15f29038e58e1b0a96483e2b369ff446becf1 upstream.

This commit fixes a race condition in the isci driver abort task and SSP
device task management path.  The race is caused when an I/O termination
in the SCU hardware is necessary because of an SSP target timeout condition,
and the check of the I/O end state races against the HW-termination-driven
end state.  The failure of the race meant that no TMF was sent to the device
to clean-up the pending I/O.

Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin at intel.com>
Reviewed-by: Lukasz Dorau <lukasz.dorau at intel.com>
Signed-off-by: James Bottomley <JBottomley at Parallels.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/scsi/isci/task.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/isci/task.c b/drivers/scsi/isci/task.c
index 6bc74eb..efd9e9e 100644
--- a/drivers/scsi/isci/task.c
+++ b/drivers/scsi/isci/task.c
@@ -491,6 +491,7 @@ int isci_task_abort_task(struct sas_task *task)
 	struct isci_tmf           tmf;
 	int                       ret = TMF_RESP_FUNC_FAILED;
 	unsigned long             flags;
+	int                       target_done_already = 0;

 	/* Get the isci_request reference from the task.  Note that
 	 * this check does not depend on the pending request list
@@ -505,9 +506,11 @@ int isci_task_abort_task(struct sas_task *task)
 	/* If task is already done, the request isn't valid */
 	if (!(task->task_state_flags & SAS_TASK_STATE_DONE) &&
 	    (task->task_state_flags & SAS_TASK_AT_INITIATOR) &&
-	    old_request)
+	    old_request) {
 		idev = isci_get_device(task->dev->lldd_dev);
-
+		target_done_already = test_bit(IREQ_COMPLETE_IN_TARGET,
+					       &old_request->flags);
+	}
 	spin_unlock(&task->task_state_lock);
 	spin_unlock_irqrestore(&ihost->scic_lock, flags);

@@ -561,7 +564,7 @@ int isci_task_abort_task(struct sas_task *task)

 	if (task->task_proto == SAS_PROTOCOL_SMP ||
 	    sas_protocol_ata(task->task_proto) ||
-	    test_bit(IREQ_COMPLETE_IN_TARGET, &old_request->flags) ||
+	    target_done_already ||
 	    test_bit(IDEV_GONE, &idev->flags)) {

 		spin_unlock_irqrestore(&ihost->scic_lock, flags);
--
1.8.1.2