diff options
author | Christoph Hellwig <hch@lst.de> | 2020-06-27 09:31:49 +0200 |
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committer | Jens Axboe <axboe@kernel.dk> | 2020-06-29 09:09:08 -0600 |
commit | 2badf06cf906c7af4bdd4bc1da62890c8e686341 (patch) | |
tree | ae4a182d31c8fd73f4760fe58d1fde7ee30bffee /block | |
parent | d92c370a16cbe0276954c761b874bd024a7e4fac (diff) | |
download | lwn-2badf06cf906c7af4bdd4bc1da62890c8e686341.tar.gz lwn-2badf06cf906c7af4bdd4bc1da62890c8e686341.zip |
block: merge __bio_associate_blkg into bio_associate_blkg_from_css
Merge __bio_associate_blkg into the only caller, which allows to slightly
reduce the RCU crticial section and better explain the code flow.
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r-- | block/bio.c | 45 |
1 files changed, 13 insertions, 32 deletions
diff --git a/block/bio.c b/block/bio.c index e1d01acce807..bc8de2432e36 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1628,52 +1628,33 @@ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src) EXPORT_SYMBOL(bioset_init_from_src); #ifdef CONFIG_BLK_CGROUP - -/** - * __bio_associate_blkg - associate a bio with the a blkg - * @bio: target bio - * @blkg: the blkg to associate - * - * This tries to associate @bio with the specified @blkg. Association failure - * is handled by walking up the blkg tree. Therefore, the blkg associated can - * be anything between @blkg and the root_blkg. This situation only happens - * when a cgroup is dying and then the remaining bios will spill to the closest - * alive blkg. - * - * A reference will be taken on the @blkg and will be released when @bio is - * freed. - */ -static void __bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) -{ - if (bio->bi_blkg) - blkg_put(bio->bi_blkg); - bio->bi_blkg = blkg_tryget_closest(blkg); -} - /** * bio_associate_blkg_from_css - associate a bio with a specified css * @bio: target bio * @css: target css * * Associate @bio with the blkg found by combining the css's blkg and the - * request_queue of the @bio. This falls back to the queue's root_blkg if - * the association fails with the css. + * request_queue of the @bio. An association failure is handled by walking up + * the blkg tree. Therefore, the blkg associated can be anything between @blkg + * and q->root_blkg. This situation only happens when a cgroup is dying and + * then the remaining bios will spill to the closest alive blkg. + * + * A reference will be taken on the blkg and will be released when @bio is + * freed. */ void bio_associate_blkg_from_css(struct bio *bio, struct cgroup_subsys_state *css) { struct request_queue *q = bio->bi_disk->queue; - struct blkcg_gq *blkg; + struct blkcg_gq *blkg = q->root_blkg; - rcu_read_lock(); + if (bio->bi_blkg) + blkg_put(bio->bi_blkg); - if (!css || !css->parent) - blkg = q->root_blkg; - else + rcu_read_lock(); + if (css && css->parent) blkg = blkg_lookup_create(css_to_blkcg(css), q); - - __bio_associate_blkg(bio, blkg); - + bio->bi_blkg = blkg_tryget_closest(blkg); rcu_read_unlock(); } EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); |