[067/200] [SCSI] libsas: fix deref before check in commit 70b25f890ce

Greg KH
2010-07-01T21:52:43Z

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

------------------

From: James Bottomley <James.Bottomley@suse.de>

commit 1b4d0d8ea7b3cbd107f345ab766416f9b38ce66a upstream.

commit 70b25f890ce9f0520c64075ce9225a5b020a513e
Author: Tejun Heo <tj@kernel.org>
Date: Thu Apr 15 09:00:08 2010 +0900

[SCSI] fix locking around blk_abort_request()

Introduced a reference before check problem, fix this by moving the
lock shorthand code to be right at the point of actual use.

Reported-by: Dan Carpenter <error27@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/scsi/libsas/sas_ata.c | 5 +++--
drivers/scsi/libsas/sas_scsi_host.c | 16 ++++++++--------
2 files changed, 11 insertions(+), 10 deletions(-)

--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -395,12 +395,13 @@ int sas_ata_init_host_and_port(struct do
void sas_ata_task_abort(struct sas_task *task)
{
struct ata_queued_cmd *qc = task->uldd_task;
- struct request_queue *q = qc->scsicmd->device->request_queue;
struct completion *waiting;
- unsigned long flags;

/* Bounce SCSI-initiated commands to the SCSI EH */
if (qc->scsicmd) {
+ struct request_queue *q = qc->scsicmd->device->request_queue;
+ unsigned long flags;
+
spin_lock_irqsave(q->queue_lock, flags);
blk_abort_request(qc->scsicmd->request);
spin_unlock_irqrestore(q->queue_lock, flags);
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -1030,8 +1030,6 @@ int __sas_task_abort(struct sas_task *ta
void sas_task_abort(struct sas_task *task)
{
struct scsi_cmnd *sc = task->uldd_task;
- struct request_queue *q = sc->device->request_queue;
- unsigned long flags;

/* Escape for libsas internal commands */
if (!sc) {
@@ -1043,13 +1041,15 @@ void sas_task_abort(struct sas_task *tas

if (dev_is_sata(task->dev)) {
sas_ata_task_abort(task);
- return;
- }
+ } else {
+ struct request_queue *q = sc->device->request_queue;
+ unsigned long flags;

- spin_lock_irqsave(q->queue_lock, flags);
- blk_abort_request(sc->request);
- spin_unlock_irqrestore(q->queue_lock, flags);
- scsi_schedule_eh(sc->device->host);
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_abort_request(sc->request);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ scsi_schedule_eh(sc->device->host);
+ }
}

int sas_slave_alloc(struct scsi_device *scsi_dev)