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 <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-05-22 17:13:21 -04:00 committed by Jens Axboe
parent 56161634e4
commit 496d5e7560
2 changed files with 5 additions and 0 deletions

View File

@ -30,6 +30,8 @@ struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT,
.cfq_leaf_weight = 2 * CFQ_WEIGHT_DEFAULT, };
EXPORT_SYMBOL_GPL(blkcg_root);
struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
static bool blkcg_policy_enabled(struct request_queue *q,

View File

@ -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; }