cgroup: s/child_subsys_mask/subtree_ss_mask/

For consistency with cgroup->subtree_control.

* cgroup->child_subsys_mask -> cgroup->subtree_ss_mask
* cgroup_calc_child_subsys_mask() -> cgroup_calc_subtree_ss_mask()
* cgroup_refresh_child_subsys_mask() -> cgroup_refresh_subtree_ss_mask()

No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 4f3c0da..c68ae7f 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -253,13 +253,12 @@
 	/*
 	 * The bitmask of subsystems enabled on the child cgroups.
 	 * ->subtree_control is the one configured through
-	 * "cgroup.subtree_control" while ->child_subsys_mask is the
-	 * effective one which may have more subsystems enabled.
-	 * Controller knobs are made available iff it's enabled in
-	 * ->subtree_control.
+	 * "cgroup.subtree_control" while ->child_ss_mask is the effective
+	 * one which may have more subsystems enabled.  Controller knobs
+	 * are made available iff it's enabled in ->subtree_control.
 	 */
-	unsigned int subtree_control;
-	unsigned int child_subsys_mask;
+	unsigned long subtree_control;
+	unsigned long subtree_ss_mask;
 
 	/* Private pointers for each registered subsystem */
 	struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT];