[PATCH 3.4 63/88] isci: Fix a race condition in the SSP task management path

Greg Kroah-Hartman
2014-06-10T00:25:13Z

From: Jeff Skirvin <jeffrey.d.skirvin@intel.com>

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@intel.com>
Reviewed-by: Lukasz Dorau <lukasz.dorau@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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
@@ -956,6 +956,7 @@ int isci_task_abort_task(struct sas_task
int ret = TMF_RESP_FUNC_FAILED;
unsigned long flags;
int perform_termination = 0;
+ 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
@@ -970,9 +971,11 @@ 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) {
isci_device = isci_lookup_device(task->dev);
-
+ target_done_already = test_bit(IREQ_COMPLETE_IN_TARGET,
+ &old_request->flags);
+ }
spin_unlock(&task->task_state_lock);
spin_unlock_irqrestore(&isci_host->scic_lock, flags);

@@ -1031,7 +1034,7 @@ 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) {

spin_unlock_irqrestore(&isci_host->scic_lock, flags);