[PATCH 4/8] nvme-pci: quiesce/unquiesce admin_q instead of start/stop its hw queues

[Ming Lei]

On Tue, Jul 04, 2017 at 10:55:08AM +0300, Sagi Grimberg wrote:
> unlike blk_mq_stop_hw_queues and blk_mq_start_stopped_hw_queues
> quiescing/unquiescing respects the submission path rcu grace.
> 
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>  drivers/nvme/host/pci.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index eb729ff70e7d..df7c8a355075 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1125,7 +1125,7 @@ static int nvme_suspend_queue(struct nvme_queue *nvmeq)
>  	spin_unlock_irq(&nvmeq->q_lock);
>  
>  	if (!nvmeq->qid && nvmeq->dev->ctrl.admin_q)
> -		blk_mq_stop_hw_queues(nvmeq->dev->ctrl.admin_q);
> +		blk_mq_quiesce_queue(nvmeq->dev->ctrl.admin_q);
>  
>  	pci_free_irq(to_pci_dev(nvmeq->dev->dev), vector, nvmeq);
>  
> @@ -1315,7 +1315,7 @@ static void nvme_dev_remove_admin(struct nvme_dev *dev)
>  		 * user requests may be waiting on a stopped queue. Start the
>  		 * queue to flush these to completion.
>  		 */
> -		blk_mq_start_stopped_hw_queues(dev->ctrl.admin_q, true);
> +		blk_mq_unquiesce_queue(dev->ctrl.admin_q);
>  		blk_cleanup_queue(dev->ctrl.admin_q);
>  		blk_mq_free_tag_set(&dev->admin_tagset);
>  	}
> @@ -1351,8 +1351,10 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev)
>  			dev->ctrl.admin_q = NULL;
>  			return -ENODEV;
>  		}
> -	} else
> -		blk_mq_start_stopped_hw_queues(dev->ctrl.admin_q, true);
> +	} else {
> +		blk_mq_unquiesce_queue(dev->ctrl.admin_q);
> +		blk_mq_kick_requeue_list(dev->ctrl.admin_q);

Again, blk_mq_kick_requeue_list() may not be required.

-- 
Ming