[SCSI] fix locking around blk_abort_request()

blk_abort_request() expects queue lock to be held by the caller.
Grab it before calling the function.

Lack of this synchronization led to infinite loop on corrupt
q->timeout_list.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/libsas/sas_ata.c

@@ -395,11 +395,15 @@ 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) {
+		spin_lock_irqsave(q->queue_lock, flags);
 		blk_abort_request(qc->scsicmd->request);
+		spin_unlock_irqrestore(q->queue_lock, flags);
 		scsi_schedule_eh(qc->scsicmd->device->host);
 		return;
 	}

drivers/scsi/libsas/sas_scsi_host.c

@@ -1030,6 +1030,8 @@ 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) {
@@ -1044,7 +1046,9 @@ void sas_task_abort(struct sas_task *task)
 		return;
 	}
 
+	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);
 }