cgroup: remove css_parent()

[linux-2.6-block.git] / include / linux / cgroup.h

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 1737db0c63fe46c558242a3f83e2e1e753aae9c4..2549493d518d0dcb07358189fe82fa81039db7c8 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -48,22 +48,28 @@ enum cgroup_subsys_id {
 };
 #undef SUBSYS
 
-/* Per-subsystem/per-cgroup state maintained by the system. */
+/*
+ * Per-subsystem/per-cgroup state maintained by the system.  This is the
+ * fundamental structural building block that controllers deal with.
+ *
+ * Fields marked with "PI:" are public and immutable and may be accessed
+ * directly without synchronization.
+ */
 struct cgroup_subsys_state {
-       /* the cgroup that this css is attached to */
+       /* PI: the cgroup that this css is attached to */
        struct cgroup *cgroup;
 
-       /* the cgroup subsystem that this css is attached to */
+       /* PI: the cgroup subsystem that this css is attached to */
        struct cgroup_subsys *ss;
 
        /* reference count - access via css_[try]get() and css_put() */
        struct percpu_ref refcnt;
 
-       /* the parent css */
+       /* PI: the parent css */
        struct cgroup_subsys_state *parent;
 
        /*
-        * Subsys-unique ID.  0 is unused and root is always 1.  The
+        * PI: Subsys-unique ID.  0 is unused and root is always 1.  The
         * matching css can be looked up using css_from_id().
         */
        int id;
@@ -669,19 +675,6 @@ struct cgroup_subsys {
 #include <linux/cgroup_subsys.h>
 #undef SUBSYS
 
-/**
- * css_parent - find the parent css
- * @css: the target cgroup_subsys_state
- *
- * Return the parent css of @css.  This function is guaranteed to return
- * non-NULL parent as long as @css isn't the root.
- */
-static inline
-struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css)
-{
-       return css->parent;
-}
-
 /**
  * task_css_set_check - obtain a task's css_set with extra access conditions
  * @task: the task to obtain css_set for