From c839e7a03f92bafd71fd145b470dcdc7f43f2d4c Mon Sep 17 00:00:00 2001 From: "Dennis Zhou (Facebook)" Date: Tue, 11 Sep 2018 14:41:33 -0400 Subject: blkcg: remove bio->bi_css and instead use bio->bi_blkg Prior patches ensured that all bios are now associated with some blkg. This now makes bio->bi_css unnecessary as blkg maintains a reference to the blkcg already. This patch removes the field bi_css and transfers corresponding uses to access via bi_blkg. Signed-off-by: Dennis Zhou Reviewed-by: Josef Bacik Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- block/bio.c | 56 +++++++++++--------------------------------------------- 1 file changed, 11 insertions(+), 45 deletions(-) (limited to 'block/bio.c') diff --git a/block/bio.c b/block/bio.c index 387480de6992..71cfe3720ea7 100644 --- a/block/bio.c +++ b/block/bio.c @@ -609,7 +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_blkcg_association(bio, bio_src); + bio_clone_blkg_association(bio, bio_src); blkcg_bio_issue_init(bio); } @@ -1956,34 +1956,6 @@ EXPORT_SYMBOL(bioset_init_from_src); #ifdef CONFIG_BLK_CGROUP -/** - * 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. - * - * 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. If @blkcg_css is NULL, a call to - * blkcg_get_css finds the current css from the kthread or task. - */ -int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) -{ - if (unlikely(bio->bi_css)) - return -EBUSY; - - if (blkcg_css) - css_get(blkcg_css); - else - blkcg_css = blkcg_get_css(); - - bio->bi_css = blkcg_css; - return 0; -} -EXPORT_SYMBOL_GPL(bio_associate_blkcg); - /** * bio_associate_blkg - associate a bio with the a blkg * @bio: target bio @@ -2033,7 +2005,6 @@ int bio_associate_blkg_from_css(struct bio *bio, struct cgroup_subsys_state *css) { css_get(css); - bio->bi_css = css; return __bio_associate_blkg_from_css(bio, css); } EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); @@ -2054,12 +2025,11 @@ int bio_associate_blkg_from_page(struct bio *bio, struct page *page) { struct cgroup_subsys_state *css; - if (unlikely(bio->bi_css)) + if (unlikely(bio->bi_blkg)) return -EBUSY; if (!page->mem_cgroup) return 0; css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys); - bio->bi_css = css; return __bio_associate_blkg_from_css(bio, css); } @@ -2085,8 +2055,7 @@ int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) rcu_read_lock(); - bio_associate_blkcg(bio, NULL); - blkcg = bio_blkcg(bio); + blkcg = css_to_blkcg(blkcg_get_css()); if (!blkcg->css.parent) { ret = bio_associate_blkg(bio, q->root_blkg); @@ -2110,30 +2079,27 @@ 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) { + /* a ref is always taken on css */ + css_put(&bio_blkcg(bio)->css); blkg_put(bio->bi_blkg); bio->bi_blkg = NULL; } } /** - * bio_clone_blkcg_association - clone blkcg association from src to dst bio + * bio_clone_blkg_association - clone blkg association from src to dst bio * @dst: destination bio * @src: source bio */ -void bio_clone_blkcg_association(struct bio *dst, struct bio *src) +void bio_clone_blkg_association(struct bio *dst, struct bio *src) { - if (src->bi_css) - WARN_ON(bio_associate_blkcg(dst, src->bi_css)); - - if (src->bi_blkg) + if (src->bi_blkg) { + css_get(&bio_blkcg(src)->css); bio_associate_blkg(dst, src->bi_blkg); + } } -EXPORT_SYMBOL_GPL(bio_clone_blkcg_association); +EXPORT_SYMBOL_GPL(bio_clone_blkg_association); #endif /* CONFIG_BLK_CGROUP */ static void __init biovec_init_slabs(void) -- cgit