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>

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c24bd0b9f93a11138b8cab60c0a686196ed2e75b..b685955d4b29bfec2f6d33c0eba8e610cb6960e2 100644 (file)
--- 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

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b69b572131e50369233c632eb582fbc604bd29ea..ff7d642a070a4b78f2ef96633f1bee7836db3937 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5717,6 +5717,28 @@ struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id)
        return css ? css : ERR_PTR(-ENOENT);
 }
 
+/**
+ * css_from_id - lookup css by id
+ * @id: the cgroup id
+ * @ss: cgroup subsys to be looked into
+ *
+ * Returns the css if there's valid one with @id, otherwise returns NULL.
+ * Should be called under rcu_read_lock().
+ */
+struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
+{
+       struct cgroup *cgrp;
+
+       rcu_lockdep_assert(rcu_read_lock_held() ||
+                          lockdep_is_held(&cgroup_mutex),
+                          "css_from_id() needs proper protection");
+
+       cgrp = idr_find(&ss->root->cgroup_idr, id);
+       if (cgrp)
+               return cgroup_css(cgrp, ss->subsys_id);
+       return NULL;
+}
+
 #ifdef CONFIG_CGROUP_DEBUG
 static struct cgroup_subsys_state *
 debug_css_alloc(struct cgroup_subsys_state *parent_css)