cgroup,rcu: convert call_rcu(__free_css_id_cb) to kfree_rcu()

The rcu callback __free_css_id_cb() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__free_css_id_cb).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 20451ce7195feb6a1f68cd45d1e3274eaf6ac68d..909a35510af53656c684021b113977c10bfbbac8 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4610,14 +4610,6 @@ bool css_is_ancestor(struct cgroup_subsys_state *child,
        return ret;
 }
 
-static void __free_css_id_cb(struct rcu_head *head)
-{
-       struct css_id *id;
-
-       id = container_of(head, struct css_id, rcu_head);
-       kfree(id);
-}
-
 void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css)
 {
        struct css_id *id = css->id;
@@ -4632,7 +4624,7 @@ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css)
        spin_lock(&ss->id_lock);
        idr_remove(&ss->idr, id->id);
        spin_unlock(&ss->id_lock);
-       call_rcu(&id->rcu_head, __free_css_id_cb);
+       kfree_rcu(id, rcu_head);
 }
 EXPORT_SYMBOL_GPL(free_css_id);