From c839e7a03f92bafd71fd145b470dcdc7f43f2d4c Mon Sep 17 00:00:00 2001 From: "Dennis Zhou (Facebook)" Date: Tue, 11 Sep 2018 14:41:33 -0400 Subject: [PATCH] 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 ++++++++------------------------------ block/bounce.c | 2 +- drivers/block/loop.c | 5 ++-- drivers/md/raid0.c | 2 +- include/linux/bio.h | 9 ++---- include/linux/blk-cgroup.h | 8 +++--- include/linux/blk_types.h | 1 - kernel/trace/blktrace.c | 4 +-- 8 files changed, 25 insertions(+), 62 deletions(-) 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) diff --git a/block/bounce.c b/block/bounce.c index 7a08703b1204..b30071ac4ec6 100644 --- a/block/bounce.c +++ b/block/bounce.c @@ -257,7 +257,7 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask, } } - bio_clone_blkcg_association(bio, bio_src); + bio_clone_blkg_association(bio, bio_src); blkcg_bio_issue_init(bio); diff --git a/drivers/block/loop.c b/drivers/block/loop.c index ea9debf59b22..abad6d15f956 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -77,6 +77,7 @@ #include #include #include +#include #include "loop.h" @@ -1760,8 +1761,8 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, /* always use the first bio's css */ #ifdef CONFIG_BLK_CGROUP - if (cmd->use_aio && rq->bio && rq->bio->bi_css) { - cmd->css = rq->bio->bi_css; + if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { + cmd->css = &bio_blkcg(rq->bio)->css; css_get(cmd->css); } else #endif diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index ac1cffd2a09b..f3fb5bb8c82a 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -542,7 +542,7 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) !discard_bio) continue; bio_chain(discard_bio, bio); - bio_clone_blkcg_association(discard_bio, bio); + bio_clone_blkg_association(discard_bio, bio); if (mddev->gendisk) trace_block_bio_remap(bdev_get_queue(rdev->bdev), discard_bio, disk_devt(mddev->gendisk), diff --git a/include/linux/bio.h b/include/linux/bio.h index c73a870ebc0e..e973876625a8 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -540,24 +540,21 @@ static inline int bio_associate_blkg_from_page(struct bio *bio, #endif #ifdef CONFIG_BLK_CGROUP -int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css); int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg); int bio_associate_blkg_from_css(struct bio *bio, struct cgroup_subsys_state *css); int bio_associate_create_blkg(struct request_queue *q, struct bio *bio); void bio_disassociate_task(struct bio *bio); -void bio_clone_blkcg_association(struct bio *dst, struct bio *src); +void bio_clone_blkg_association(struct bio *dst, struct bio *src); #else /* CONFIG_BLK_CGROUP */ -static inline int bio_associate_blkcg(struct bio *bio, - struct cgroup_subsys_state *blkcg_css) { return 0; } static inline int bio_associate_blkg_from_css(struct bio *bio, struct cgroup_subsys_state *css) { return 0; } static inline int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) { return 0; } static inline void bio_disassociate_task(struct bio *bio) { } -static inline void bio_clone_blkcg_association(struct bio *dst, - struct bio *src) { } +static inline void bio_clone_blkg_association(struct bio *dst, + struct bio *src) { } #endif /* CONFIG_BLK_CGROUP */ #ifdef CONFIG_HIGHMEM diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index a6b6e741a75e..c41cfcc2b4d8 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -308,8 +308,8 @@ static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) */ static inline struct blkcg *__bio_blkcg(struct bio *bio) { - if (bio && bio->bi_css) - return css_to_blkcg(bio->bi_css); + if (bio && bio->bi_blkg) + return bio->bi_blkg->blkcg; return css_to_blkcg(blkcg_css()); } @@ -323,8 +323,8 @@ static inline struct blkcg *__bio_blkcg(struct bio *bio) */ static inline struct blkcg *bio_blkcg(struct bio *bio) { - if (bio && bio->bi_css) - return css_to_blkcg(bio->bi_css); + if (bio && bio->bi_blkg) + return bio->bi_blkg->blkcg; return NULL; } diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index f6dfb30737d8..9578c7ab1eb6 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -178,7 +178,6 @@ struct bio { * release. Read comment on top of bio_associate_current(). */ struct io_context *bi_ioc; - struct cgroup_subsys_state *bi_css; struct blkcg_gq *bi_blkg; struct bio_issue bi_issue; #endif diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 2868d85f1fb1..fac0ddf8a8e2 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -764,9 +764,9 @@ blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) return NULL; - if (!bio->bi_css) + if (!bio->bi_blkg) return NULL; - return cgroup_get_kernfs_id(bio->bi_css->cgroup); + return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup); } #else static union kernfs_node_id *