diff options
Diffstat (limited to 'block/bio.c')
| -rw-r--r-- | block/bio.c | 174 |
1 files changed, 47 insertions, 127 deletions
diff --git a/block/bio.c b/block/bio.c index bbfeb4ee2892..4a5a036268fb 100644 --- a/block/bio.c +++ b/block/bio.c @@ -609,9 +609,7 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src) bio->bi_iter = bio_src->bi_iter; bio->bi_io_vec = bio_src->bi_io_vec; - bio_clone_blkg_association(bio, bio_src); - - blkcg_bio_issue_init(bio); + bio_clone_blkcg_association(bio, bio_src); } EXPORT_SYMBOL(__bio_clone_fast); @@ -1956,151 +1954,69 @@ 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. - */ -int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) -{ - if (unlikely(bio->bi_blkg)) - return -EBUSY; - bio->bi_blkg = blkg_tryget_closest(blkg); - return 0; -} - -/** - * __bio_associate_blkg_from_css - internal blkg association function - * - * This in the core association function that all association paths rely on. - * A blkg reference is taken which is released upon freeing of the bio. - */ -static int __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; - int ret; - - rcu_read_lock(); - - if (!css || !css->parent) - blkg = q->root_blkg; - else - blkg = blkg_lookup_create(css_to_blkcg(css), q); - - ret = bio_associate_blkg(bio, blkg); - - rcu_read_unlock(); - return ret; -} - -/** - * 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. - */ -int bio_associate_blkg_from_css(struct bio *bio, - struct cgroup_subsys_state *css) -{ - if (unlikely(bio->bi_blkg)) - return -EBUSY; - return __bio_associate_blkg_from_css(bio, css); -} -EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); - #ifdef CONFIG_MEMCG /** - * bio_associate_blkg_from_page - associate a bio with the page's blkg + * bio_associate_blkcg_from_page - associate a bio with the page's blkcg * @bio: target bio * @page: the page to lookup the blkcg from * - * Associate @bio with the blkg from @page's owning memcg and the respective - * request_queue. If cgroup_e_css returns NULL, fall back to the queue's - * root_blkg. - * - * Note: this must be called after bio has an associated device. + * Associate @bio with the blkcg from @page's owning memcg. This works like + * every other associate function wrt references. */ -int bio_associate_blkg_from_page(struct bio *bio, struct page *page) +int bio_associate_blkcg_from_page(struct bio *bio, struct page *page) { - struct cgroup_subsys_state *css; - int ret; + struct cgroup_subsys_state *blkcg_css; - if (unlikely(bio->bi_blkg)) + if (unlikely(bio->bi_css)) return -EBUSY; if (!page->mem_cgroup) return 0; - - rcu_read_lock(); - - css = cgroup_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys); - - ret = __bio_associate_blkg_from_css(bio, css); - - rcu_read_unlock(); - return ret; + blkcg_css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, + &io_cgrp_subsys); + bio->bi_css = blkcg_css; + return 0; } #endif /* CONFIG_MEMCG */ /** - * bio_associate_create_blkg - associate a bio with a blkg from q - * @q: request_queue where bio is going + * bio_associate_blkcg - associate a bio with the specified blkcg * @bio: target bio + * @blkcg_css: css of the blkcg to associate + * + * Associate @bio with the blkcg specified by @blkcg_css. Block layer will + * treat @bio as if it were issued by a task which belongs to the blkcg. * - * Associate @bio with the blkg found from the bio's css and the request_queue. - * If one is not found, bio_lookup_blkg creates the blkg. This falls back to - * the queue's root_blkg if association fails. + * This function takes an extra reference of @blkcg_css which will be put + * when @bio is released. The caller must own @bio and is responsible for + * synchronizing calls to this function. */ -int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) +int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) { - struct cgroup_subsys_state *css; - int ret = 0; - - /* someone has already associated this bio with a blkg */ - if (bio->bi_blkg) - return ret; - - rcu_read_lock(); - - css = blkcg_css(); - - ret = __bio_associate_blkg_from_css(bio, css); - - rcu_read_unlock(); - return ret; + if (unlikely(bio->bi_css)) + return -EBUSY; + css_get(blkcg_css); + bio->bi_css = blkcg_css; + return 0; } +EXPORT_SYMBOL_GPL(bio_associate_blkcg); /** - * bio_reassociate_blkg - reassociate a bio with a blkg from q - * @q: request_queue where bio is going + * bio_associate_blkg - associate a bio with the specified blkg * @bio: target bio + * @blkg: the blkg to associate * - * When submitting a bio, multiple recursive calls to make_request() may occur. - * This causes the initial associate done in blkcg_bio_issue_check() to be - * incorrect and reference the prior request_queue. This performs reassociation - * when this situation happens. + * Associate @bio with the blkg specified by @blkg. This is the queue specific + * blkcg information associated with the @bio, a reference will be taken on the + * @blkg and will be freed when the bio is freed. */ -int bio_reassociate_blkg(struct request_queue *q, struct bio *bio) +int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) { - if (bio->bi_blkg) { - blkg_put(bio->bi_blkg); - bio->bi_blkg = NULL; - } - - return bio_associate_create_blkg(q, bio); + if (unlikely(bio->bi_blkg)) + return -EBUSY; + if (!blkg_try_get(blkg)) + return -ENODEV; + bio->bi_blkg = blkg; + return 0; } /** @@ -2113,6 +2029,10 @@ void bio_disassociate_task(struct bio *bio) put_io_context(bio->bi_ioc); bio->bi_ioc = NULL; } + if (bio->bi_css) { + css_put(bio->bi_css); + bio->bi_css = NULL; + } if (bio->bi_blkg) { blkg_put(bio->bi_blkg); bio->bi_blkg = NULL; @@ -2120,16 +2040,16 @@ void bio_disassociate_task(struct bio *bio) } /** - * bio_clone_blkg_association - clone blkg association from src to dst bio + * bio_clone_blkcg_association - clone blkcg association from src to dst bio * @dst: destination bio * @src: source bio */ -void bio_clone_blkg_association(struct bio *dst, struct bio *src) +void bio_clone_blkcg_association(struct bio *dst, struct bio *src) { - if (src->bi_blkg) - bio_associate_blkg(dst, src->bi_blkg); + if (src->bi_css) + WARN_ON(bio_associate_blkcg(dst, src->bi_css)); } -EXPORT_SYMBOL_GPL(bio_clone_blkg_association); +EXPORT_SYMBOL_GPL(bio_clone_blkcg_association); #endif /* CONFIG_BLK_CGROUP */ static void __init biovec_init_slabs(void) |