diff options
Diffstat (limited to 'block/bio.c')
| -rw-r--r-- | block/bio.c | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/block/bio.c b/block/bio.c index cbce3e2208f4..d2501a479256 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1983,6 +1983,29 @@ struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_ EXPORT_SYMBOL(bioset_create_nobvec); #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. + */ +int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) +{ + 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_associate_current - associate a bio with %current * @bio: target bio @@ -1999,28 +2022,20 @@ EXPORT_SYMBOL(bioset_create_nobvec); int bio_associate_current(struct bio *bio) { struct io_context *ioc; - struct cgroup_subsys_state *css; - if (bio->bi_ioc) + if (bio->bi_css) return -EBUSY; ioc = current->io_context; if (!ioc) return -ENOENT; - /* acquire active ref on @ioc and associate */ get_io_context_active(ioc); bio->bi_ioc = ioc; - - /* associate blkcg if exists */ - rcu_read_lock(); - css = task_css(current, blkio_cgrp_id); - if (css && css_tryget_online(css)) - bio->bi_css = css; - rcu_read_unlock(); - + bio->bi_css = task_get_css(current, io_cgrp_id); return 0; } +EXPORT_SYMBOL_GPL(bio_associate_current); /** * bio_disassociate_task - undo bio_associate_current() |