Re: [PATCH v6 08/12] block, scsi: Introduce blk_pm_runtime_exit()

["jianchao.wang" <jianchao.w.wang@xxxxxxxxxx>]

Hi Bart

On 08/11/2018 12:17 AM, Bart Van Assche wrote:
> void blk_pm_runtime_exit(struct request_queue *q)
> {
> 	if (!q->dev)
> 		return;
> 
> 	pm_runtime_get_sync(q->dev);
> 	blk_freeze_queue(q);
> 	q->dev = NULL;
> 	blk_unfreeze_queue(q);
> }

I'm afraid this will not work.

In following patch:

@@ -972,6 +972,8 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
 		if (success)
 			return 0;
 
+		blk_pm_request_resume(q);
+
 		if (flags & BLK_MQ_REQ_NOWAIT)
 			return -EBUSY;

We could still invoke blk_pm_request_resume even if the queue is frozen.

And we have blk_pm_request_resume later as following:

+static inline void blk_pm_request_resume(struct request_queue *q)
+{
+	if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
+		       q->rpm_status == RPM_SUSPENDING))
+		pm_request_resume(q->dev);
+}

Thanks
Jianchao