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-rw-r--r--mm/memcontrol.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 48747ef5b88f..5579e762b1ce 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4062,11 +4062,13 @@ static DEFINE_IDR(mem_cgroup_idr);
static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
{
+ VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
atomic_add(n, &memcg->id.ref);
}
static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
{
+ VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
if (atomic_sub_and_test(n, &memcg->id.ref)) {
idr_remove(&mem_cgroup_idr, memcg->id.id);
memcg->id.id = 0;
@@ -4255,8 +4257,10 @@ fail:
static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
/* Online state pins memcg ID, memcg ID pins CSS */
- mem_cgroup_id_get(mem_cgroup_from_css(css));
+ atomic_set(&memcg->id.ref, 1);
css_get(css);
return 0;
}