cgroup: move cgroup->serial_nr into cgroup_subsys_state

We're moving towards using cgroup_subsys_states as the fundamental
structural blocks.  All csses including the cgroup->self and actual
ones now form trees through css->children and ->sibling which follow
the same rules as what cgroup->children and ->sibling followed.  This
patch moves cgroup->serial_nr which is used to implement css iteration
into css.

Note that all csses, regardless of their types, allocate their serial
numbers from the same monotonically increasing counter.  This doesn't
affect the ordering needed by css iteration or cause any other
material behavior changes.  This will be used to update css iteration.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index cf8ba26..ebe7ce4 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -80,6 +80,14 @@ struct cgroup_subsys_state {
 
 	unsigned int flags;
 
+	/*
+	 * Monotonically increasing unique serial number which defines a
+	 * uniform order among all csses.  It's guaranteed that all
+	 * ->children lists are in the ascending order of ->serial_nr and
+	 * used to allow interrupting and resuming iterations.
+	 */
+	u64 serial_nr;
+
 	/* percpu_ref killing and RCU release */
 	struct rcu_head rcu_head;
 	struct work_struct destroy_work;
@@ -178,14 +186,6 @@ struct cgroup {
 	struct kernfs_node *kn;		/* cgroup kernfs entry */
 	struct kernfs_node *populated_kn; /* kn for "cgroup.subtree_populated" */
 
-	/*
-	 * Monotonically increasing unique serial number which defines a
-	 * uniform order among all cgroups.  It's guaranteed that all
-	 * ->children lists are in the ascending order of ->serial_nr.
-	 * It's used to allow interrupting and resuming iterations.
-	 */
-	u64 serial_nr;
-
 	/* the bitmask of subsystems enabled on the child cgroups */
 	unsigned int child_subsys_mask;