Merge branch 'for-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup changes from Tejun Heo:
 "Three mostly trivial patches.  The biggest change is that blkio is now
  initialized before memcg which will be needed to make memcg and blkcg
  cooperate on writeback IOs"

* 'for-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: add dummy css_put() for !CONFIG_CGROUPS
  cgroup: reorder SUBSYS(blkio) in cgroup_subsys.h
  Update of Documentation/cgroups/00-INDEX

Documentation/cgroups/00-INDEX

@@ -24,3 +24,5 @@ net_prio.txt
 	- Network priority cgroups details and usages.
 resource_counter.txt
 	- Resource Counter API.
+unified-hierarchy.txt
+	- Description the new/next cgroup interface.

include/linux/cgroup.h

@@ -943,6 +943,8 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
 
 #else /* !CONFIG_CGROUPS */
 
+struct cgroup_subsys_state;
+
 static inline int cgroup_init_early(void) { return 0; }
 static inline int cgroup_init(void) { return 0; }
 static inline void cgroup_fork(struct task_struct *p) {}
@@ -955,6 +957,8 @@ static inline int cgroupstats_build(struct cgroupstats *stats,
 	return -EINVAL;
 }
 
+static inline void css_put(struct cgroup_subsys_state *css) {}
+
 /* No cgroups - nothing to do */
 static inline int cgroup_attach_task_all(struct task_struct *from,
 					 struct task_struct *t)

include/linux/cgroup_subsys.h

@@ -15,6 +15,10 @@ SUBSYS(cpu)
 SUBSYS(cpuacct)
 #endif
 
+#if IS_ENABLED(CONFIG_BLK_CGROUP)
+SUBSYS(blkio)
+#endif
+
 #if IS_ENABLED(CONFIG_MEMCG)
 SUBSYS(memory)
 #endif
@@ -31,10 +35,6 @@ SUBSYS(freezer)
 SUBSYS(net_cls)
 #endif
 
-#if IS_ENABLED(CONFIG_BLK_CGROUP)
-SUBSYS(blkio)
-#endif
-
 #if IS_ENABLED(CONFIG_CGROUP_PERF)
 SUBSYS(perf_event)
 #endif