[SCSI] libsas: fix deref before check in commit 70b25f89

commit 70b25f89
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: NDan Carpenter <error27@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

drivers/scsi/libsas/sas_ata.c

@@ -395,12 +395,13 @@ int sas_ata_init_host_and_port(struct domain_device *found_dev,
 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);

drivers/scsi/libsas/sas_scsi_host.c

@@ -1030,8 +1030,6 @@ int __sas_task_abort(struct sas_task *task)
 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 *task)
 
 	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)