Re: [PATCH] block: Revert "let blkcg_gq grab request queue's refcnt"

[Bart Van Assche <bvanassche@xxxxxxx>]

On 2/1/23 07:55, Ming Lei wrote:
> The following patch can address the blkg leak issue:
>
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index cb110fc51940..78f855c34746 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -2034,6 +2034,10 @@ void blk_cgroup_bio_start(struct bio *bio)
>   	struct blkg_iostat_set *bis;
>   	unsigned long flags;
>   
> +	/* Root-level stats are sourced from system-wide IO stats */
> +	if (!cgroup_parent(blkcg->css.cgroup))
> +		return;
> +
>   	cpu = get_cpu();
>   	bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu);
>   	flags = u64_stats_update_begin_irqsave(&bis->sync);

The above patch passes my tests. Feel free to add:

Tested-by: Bart van Assche <bvanassche@xxxxxxx>