Re: [PATCH 06/15] blkcg: always associate a bio with a blkg

Tejun Heo
2018-08-31T23:16:09Z

Hello,

On Thu, Aug 30, 2018 at 09:53:47PM -0400, Dennis Zhou wrote:
> From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>
>
> Previously, blkg's were only assigned as needed by blk-iolatency and
> blk-throttle. bio->css was also always being associated while blkg was
> being looked up and then thrown away in blkcg_bio_issue_check.
>
> This patch beings the cleanup of bio->css and bio->bi_blkg by always
^
begins

> +int bio_associate_create_blkg(struct request_queue *q, struct bio *bio)
> +{
> + struct blkcg *blkcg;
> + struct blkcg_gq *blkg;
> + int ret = 0;
> +
> + /* someone has already associated this bio with a blkg */
> + if (bio->bi_blkg)
> + return ret;
> +
> + rcu_read_lock();
> +
> + bio_associate_blkcg(bio, NULL);
> + blkcg = bio_blkcg(bio);
> +
> + if (!blkcg->css.parent) {
> + ret = bio_associate_blkg(bio, q->root_blkg);
> + goto assoc_out;
> + }
> +
> + blkg = blkg_lookup_create(blkcg, q);
> + if (IS_ERR(blkg))
> + blkg = q->root_blkg;
> +
> + ret = bio_associate_blkg(bio, blkg);
> +assoc_out:

Maybe if/else instead of goto?

Other than that,

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

--
tejun