[PATCH v3 2/8] nvme-fc: quiesce/unquiesce admin_q instead of start/stop its hw queues

[Ming Lei]

On Wed, Jul 05, 2017 at 08:00:31PM +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.
> 
> Also, make sure to unquiesce before cleanup the admin queue.
> 
> Reviewed-By: James Smart <james.smart at broadcom.com>
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>  drivers/nvme/host/fc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 50cc3b2b0e11..8d55e7827932 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -1703,6 +1703,7 @@ nvme_fc_ctrl_free(struct kref *ref)
>  	list_del(&ctrl->ctrl_list);
>  	spin_unlock_irqrestore(&ctrl->rport->lock, flags);
>  
> +	blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);
>  	blk_cleanup_queue(ctrl->ctrl.admin_q);
>  	blk_mq_free_tag_set(&ctrl->admin_tag_set);
>  
> @@ -2321,7 +2322,7 @@ nvme_fc_create_association(struct nvme_fc_ctrl *ctrl)
>  		goto out_delete_hw_queue;
>  
>  	if (ctrl->ctrl.state != NVME_CTRL_NEW)
> -		blk_mq_start_stopped_hw_queues(ctrl->ctrl.admin_q, true);
> +		blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);
>  
>  	ret = nvmf_connect_admin_queue(&ctrl->ctrl);
>  	if (ret)
> @@ -2475,7 +2476,7 @@ nvme_fc_delete_association(struct nvme_fc_ctrl *ctrl)
>  	 * use blk_mq_tagset_busy_itr() and the transport routine to
>  	 * terminate the exchanges.
>  	 */
> -	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
> +	blk_mq_quiesce_queue(ctrl->ctrl.admin_q);
>  	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
>  				nvme_fc_terminate_exchange, &ctrl->ctrl);
>  
> -- 
> 2.7.4
> 

Maybe it is a little better to the blk_mq_unquiesce_queue() before
blk_cleanup_queue() after blk_mq_tagset_busy_iter() in
nvme_fc_delete_association(). But it shouldn't be a big deal.

So looks fine,

	Reviewed-by: Ming Lei <ming.lei at redhat.com>


-- 
Ming