From 496d5e7560dbb84399dbd92316fc33857aa83900 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:21 -0400 Subject: blkcg: add blkcg_root_css Add global constant blkcg_root_css which points to &blkcg_root.css. This will be used by cgroup writeback support. If blkcg is disabled, it's defined as ERR_PTR(-EINVAL). v2: The declarations moved to include/linux/blk-cgroup.h as suggested by Vivek. Signed-off-by: Tejun Heo Cc: Vivek Goyal Cc: Jens Axboe Signed-off-by: Jens Axboe --- include/linux/blk-cgroup.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/blk-cgroup.h') diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 51f95b34d3f0..65f0c178fd04 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -134,6 +134,7 @@ struct blkcg_policy { }; extern struct blkcg blkcg_root; +extern struct cgroup_subsys_state * const blkcg_root_css; struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q); struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, @@ -570,6 +571,8 @@ struct blkcg_gq { struct blkcg_policy { }; +#define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL)) + #ifdef CONFIG_BLOCK static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } -- cgit v1.2.3