Re: [PATCH v2 -next] blk-cgroup: synchoronize blkg creation against policy deactivation

[Tejun Heo]

On Wed, Oct 13, 2021 at 08:44:56PM +0800, Yu Kuai wrote:
> @@ -1401,6 +1406,7 @@ void blkcg_deactivate_policy(struct request_queue *q,
>  	if (queue_is_mq(q))
>  		blk_mq_freeze_queue(q);
>  
> +	mutex_lock(&q->blkg_lock);
>  	spin_lock_irq(&q->queue_lock);

Given that deactivation drains q_usage_counter through
blk_mq_freeze_queue(), can't the blkg_conf_prep() just pin the usage count?

Thanks.

-- 
tejun