cgroup: change cgroup_from_id() to css_from_id()

Now we want cgroup core to always provide the css to use to the
subsystems, so change this API to css_from_id().

Uninline css_from_id(), because it's getting bigger and cgroup_css()
has been unexported.

While at it, remove the #ifdef, and shuffle the order of the args.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 2 insertions, 18 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c24bd0b9f93a..b685955d4b29 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -741,27 +741,11 @@ static inline struct cgroup *task_cgroup(struct task_struct *task,
 	return task_css(task, subsys_id)->cgroup;
 }
 
-/**
- * cgroup_from_id - lookup cgroup by id
- * @ss: cgroup subsys to be looked into
- * @id: the cgroup id
- *
- * Returns the cgroup if there's valid one with @id, otherwise returns NULL.
- * Should be called under rcu_read_lock().
- */
-static inline struct cgroup *cgroup_from_id(struct cgroup_subsys *ss, int id)
-{
-#ifdef CONFIG_PROVE_RCU
-	rcu_lockdep_assert(rcu_read_lock_held() ||
-			   lockdep_is_held(&cgroup_mutex),
-			   "cgroup_from_id() needs proper protection");
-#endif
-	return idr_find(&ss->root->cgroup_idr, id);
-}
-
 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
 					   struct cgroup_subsys_state *parent);
 
+struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
+
 /**
  * css_for_each_child - iterate through children of a css
  * @pos: the css * to use as the loop cursor