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authorDennis Zhou (Facebook) <dennisszhou@gmail.com>2018-09-11 21:41:33 +0300
committerJens Axboe <axboe@kernel.dk>2018-09-22 05:29:13 +0300
commitc839e7a03f92bafd71fd145b470dcdc7f43f2d4c (patch)
tree2327729d2f67268d179beb22f4ef9db44b156af1 /block/bio.c
parentbdc2491708c47601603918a9a20acddef6e1d814 (diff)
downloadlinux-c839e7a03f92bafd71fd145b470dcdc7f43f2d4c.tar.xz
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 <dennisszhou@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bio.c')
-rw-r--r--block/bio.c56
1 files changed, 11 insertions, 45 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);
}
@@ -1957,34 +1957,6 @@ 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
* @blkg: the blkg to associate
@@ -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)