diff options
| -rw-r--r-- | block/blk-cgroup.c | 16 | ||||
| -rw-r--r-- | include/linux/blk-cgroup.h | 6 |
2 files changed, 21 insertions, 1 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 2acef6a64954..c5dc833212e1 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1006,6 +1006,21 @@ unlock: return ret; } +static int blkcg_css_online(struct cgroup_subsys_state *css) +{ + struct blkcg *blkcg = css_to_blkcg(css); + struct blkcg *parent = blkcg_parent(blkcg); + + /* + * blkcg_pin_online() is used to delay blkcg offline so that blkgs + * don't go offline while cgwbs are still active on them. Pin the + * parent so that offline always happens towards the root. + */ + if (parent) + blkcg_pin_online(parent); + return 0; +} + /** * blkcg_init_queue - initialize blkcg part of request queue * @q: request_queue to initialize @@ -1199,6 +1214,7 @@ static void blkcg_exit(struct task_struct *tsk) struct cgroup_subsys io_cgrp_subsys = { .css_alloc = blkcg_css_alloc, + .css_online = blkcg_css_online, .css_offline = blkcg_css_offline, .css_free = blkcg_css_free, .can_attach = blkcg_can_attach, diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 7fb7caa55a3d..35f8ffe92b70 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -436,8 +436,12 @@ static inline void blkcg_pin_online(struct blkcg *blkcg) */ static inline void blkcg_unpin_online(struct blkcg *blkcg) { - if (refcount_dec_and_test(&blkcg->online_pin)) + do { + if (!refcount_dec_and_test(&blkcg->online_pin)) + break; blkcg_destroy_blkgs(blkcg); + blkcg = blkcg_parent(blkcg); + } while (blkcg); } /** |