Re: [PATCH 1/2] nvme: pci: simplify timeout handling

[jianchao.wang]

Hi Ming

Thanks for your wonderful solution. :)

On 04/26/2018 08:39 PM, Ming Lei wrote:
> +/*
> + * This one is called after queues are quiesced, and no in-fligh timeout
> + * and nvme interrupt handling.
> + */
> +static void nvme_pci_cancel_request(struct request *req, void *data,
> +             bool reserved)
> +{
> +     /* make sure timed-out requests are covered too */
> +     if (req->rq_flags & RQF_MQ_TIMEOUT_EXPIRED) {
> +             req->aborted_gstate = 0;
> +             req->rq_flags &= ~RQF_MQ_TIMEOUT_EXPIRED;
> +     }
> +
> +     nvme_cancel_request(req, data, reserved);
> +}
> +
>  static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
>  {
>       int i;
> @@ -2223,10 +2316,17 @@ static void nvme_dev_disable(struct nvme_dev *dev, 
> bool shutdown)
>       for (i = dev->ctrl.queue_count - 1; i >= 0; i--)
>               nvme_suspend_queue(&dev->queues[i]);
>  
> +     /*
> +      * safe to sync timeout after queues are quiesced, then all
> +      * requests(include the time-out ones) will be canceled.
> +      */
> +     nvme_sync_queues(&dev->ctrl);
> +     blk_sync_queue(dev->ctrl.admin_q);
> +
Looks like blk_sync_queue cannot drain all the timeout work.

blk_sync_queue
  -> del_timer_sync          
                          blk_mq_timeout_work
                            -> mod_timer
  -> cancel_work_sync
the timeout work may come back again.
we may need to force all the in-flight requests to be timed out with 
blk_abort_request

>       nvme_pci_disable(dev);

the interrupt will not come, but there maybe running one.
a synchronize_sched() here ?

Thanks
Jianchao
>  
> -     blk_mq_tagset_busy_iter(&dev->tagset, nvme_cancel_request, &dev->ctrl);
> -     blk_mq_tagset_busy_iter(&dev->admin_tagset, nvme_cancel_request, 
> &dev->ctrl);
> +     blk_mq_tagset_busy_iter(&dev->tagset, nvme_pci_cancel_request, 
> &dev->ctrl);
> +     blk_mq_tagset_busy_iter(&dev->admin_tagset, nvme_pci_cancel_request, 
> &dev->ctrl);