[PATCH 3/8] nvme-loop: quiesce admin_q instead of stopping hw queues

[Ming Lei]

On Tue, Jul 04, 2017 at 10:55:07AM +0300, Sagi Grimberg wrote:
> Before we iterate over the tags, we need to make sure that
> no inflight requests are being queued, so use quiesce
> helper for that.
> 
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>  drivers/nvme/target/loop.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
> index 3d51341e62ee..891002ee005f 100644
> --- a/drivers/nvme/target/loop.c
> +++ b/drivers/nvme/target/loop.c
> @@ -434,7 +434,7 @@ static void nvme_loop_shutdown_ctrl(struct nvme_loop_ctrl *ctrl)
>  	if (ctrl->ctrl.state == NVME_CTRL_LIVE)
>  		nvme_shutdown_ctrl(&ctrl->ctrl);
>  
> -	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_cancel_request, &ctrl->ctrl);
>  	nvme_loop_destroy_admin_queue(ctrl);

Is the queue killed before calling nvme_loop_destroy_admin_queue()? If
not, simply quiescing and not unquiescing will hang in
blk_cleanup_queue().  So I suggest to put blk_mq_unquiesce_queue()
after blk_mq_tagset_busy_iter().

-- 
Ming