Hello, Some nitpicks. On Tue, Oct 19, 2021 at 10:41:32AM +0800, Yu Kuai wrote: ... > Because blkcg_deactivate_policy() require queue to be freezed, thus grab ^ ^ ^ requires frozen we can grab > q_usage_counter to synchoronize blkg_conf_prep() against > blkcg_deactivate_policy(). ... > + /* > + * blkcg_deactivate_policy() require queue to be freezed, thus grab > + * q_usage_counter to prevent concurrent with blkcg_deactivate_policy(). > + */ Same here. Looks good otherwise. Please feel free to add Acked-by: Tejun Heo <tj@xxxxxxxxxx> Thanks. -- tejun