X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=include%2Flinux%2Fcgroup.h;h=bbf4d89b56a8ccab699fe8342c778ca780a22d1b;hb=e14880f7bb7e0dc0933af304998371dd543ceb40;hp=4dfcd0e1b73e290483931caa7cd68d47da6b1e37;hpb=b414dc09a31d41d696093a4cce9fb2853a5ecd4e;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 4dfcd0e..bbf4d89 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -720,6 +720,24 @@ static inline struct cgroup* task_cgroup(struct task_struct *task,
 	return task_subsys_state(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 *cgroup_next_sibling(struct cgroup *pos);
 
 /**