Messages in this thread | | | Date | Fri, 7 Sep 2018 10:27:30 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH 03/12] blkcg: convert blkg_lookup_create to find closest blkg |
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Hello,
On Thu, Sep 06, 2018 at 05:10:36PM -0400, Dennis Zhou wrote: > @@ -2021,9 +2021,7 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) > { > if (unlikely(bio->bi_blkg)) > return -EBUSY; > + bio->bi_blkg = blkg_try_get_closest(blkg); > return 0;
It prolly would be a good idea to point out that the associated blkg might not be the same one passed in. Maybe this gets cleared up later in the series?
> @@ -298,14 +297,23 @@ struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, > while (true) { > struct blkcg *pos = blkcg; > struct blkcg *parent = blkcg_parent(blkcg); > - > - while (parent && !__blkg_lookup(parent, q, false)) { > + struct blkcg_gq *ret_blkg = NULL; > + > + while (parent) { > + blkg = __blkg_lookup(parent, q, false); > + if (blkg) { > + /* remember closest blkg */ > + ret_blkg = blkg; > + break; > + } > pos = parent; > parent = blkcg_parent(parent); > } > > blkg = blkg_create(pos, q, NULL); > - if (pos == blkcg || IS_ERR(blkg)) > + if (IS_ERR(blkg)) > + return ret_blkg ?: q->root_blkg;
Why not ret_blkg here?
Thanks.
-- tejun
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