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

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>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 88f7446..8c496b5 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -395,12 +395,13 @@
 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);