[ 15/99] SCSI: isci: Fix a race condition in the SSP task management path

From: Greg Kroah-Hartman
Date: Fri Aug 02 2013 - 06:54:34 EST

3.10-stable review patch. If anyone has any objections, please let me know.


From: Jeff Skirvin <jeffrey.d.skirvin@xxxxxxxxx>

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@xxxxxxxxx>
Reviewed-by: Lukasz Dorau <lukasz.dorau@xxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/scsi/isci/task.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/scsi/isci/task.c
+++ b/drivers/scsi/isci/task.c
@@ -491,6 +491,7 @@ int isci_task_abort_task(struct sas_task
struct isci_tmf tmf;
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
/* 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_irqrestore(&ihost->scic_lock, flags);

@@ -561,7 +564,7 @@ int isci_task_abort_task(struct sas_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);

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