scsi: scsi_transport_fc: Hold queue lock while calling blk_run_queue_async()

It is required to hold the queue lock when calling blk_run_queue_async()
to avoid that a race between blk_run_queue_async() and
blk_cleanup_queue() is triggered. Additionally, remove the get_device()
and put_device() calls from fc_bsg_goose_queue. It is namely the
responsibility of the caller of fc_bsg_goose_queue() to ensure that the
bsg queue does not disappear while fc_bsg_goose_queue() is in progress.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: James Smart <james.smart@avagotech.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_transport_fc.c

@@ -3855,15 +3855,15 @@ fc_bsg_host_dispatch(struct request_queue *q, struct Scsi_Host *shost,
 static void
 fc_bsg_goose_queue(struct fc_rport *rport)
 {
-	if (!rport->rqst_q)
+	struct request_queue *q = rport->rqst_q;
+	unsigned long flags;
+
+	if (!q)
 		return;
 
-	/*
-	 * This get/put dance makes no sense
-	 */
-	get_device(&rport->dev);
-	blk_run_queue_async(rport->rqst_q);
-	put_device(&rport->dev);
+	spin_lock_irqsave(q->queue_lock, flags);
+	blk_run_queue_async(q);
+	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 /**