1 files changed, 31 insertions, 6 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1f14a430c656..f009a14918d2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6007,7 +6007,6 @@ static struct cftype mem_cgroup_files[] = {
         },
         {
                 .name = "use_hierarchy",
-                .flags = CFTYPE_INSANE,
                 .write_u64 = mem_cgroup_hierarchy_write,
                 .read_u64 = mem_cgroup_hierarchy_read,
         },
@@ -6411,6 +6410,29 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
         __mem_cgroup_free(memcg);
 }
 
+/**
+ * mem_cgroup_css_reset - reset the states of a mem_cgroup
+ * @css: the target css
+ *
+ * Reset the states of the mem_cgroup associated with @css.  This is
+ * invoked when the userland requests disabling on the default hierarchy
+ * but the memcg is pinned through dependency.  The memcg should stop
+ * applying policies and should revert to the vanilla state as it may be
+ * made visible again.
+ *
+ * The current implementation only resets the essential configurations.
+ * This needs to be expanded to cover all the visible parts.
+ */
+static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
+{
+        struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+        mem_cgroup_resize_limit(memcg, ULLONG_MAX);
+        mem_cgroup_resize_memsw_limit(memcg, ULLONG_MAX);
+        memcg_update_kmem_limit(memcg, ULLONG_MAX);
+        res_counter_set_soft_limit(&memcg->res, ULLONG_MAX);
+}
+
 #ifdef CONFIG_MMU
 /* Handlers for move charge at task migration. */
 #define PRECHARGE_COUNT_AT_ONCE 256
@@ -7005,16 +7027,17 @@ static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
 
 /*
  * Cgroup retains root cgroups across [un]mount cycles making it necessary
- * to verify sane_behavior flag on each mount attempt.
+ * to verify whether we're attached to the default hierarchy on each mount
+ * attempt.
  */
 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
 {
         /*
-         * use_hierarchy is forced with sane_behavior.  cgroup core
+         * use_hierarchy is forced on the default hierarchy.  cgroup core
          * guarantees that @root doesn't have any children, so turning it
          * on for the root memcg is enough.
          */
-        if (cgroup_sane_behavior(root_css->cgroup))
+        if (cgroup_on_dfl(root_css->cgroup))
                 mem_cgroup_from_css(root_css)->use_hierarchy = true;
 }
 
@@ -7023,11 +7046,12 @@ struct cgroup_subsys memory_cgrp_subsys = {
         .css_online = mem_cgroup_css_online,
         .css_offline = mem_cgroup_css_offline,
         .css_free = mem_cgroup_css_free,
+        .css_reset = mem_cgroup_css_reset,
         .can_attach = mem_cgroup_can_attach,
         .cancel_attach = mem_cgroup_cancel_attach,
         .attach = mem_cgroup_move_task,
         .bind = mem_cgroup_bind,
-        .base_cftypes = mem_cgroup_files,
+        .legacy_cftypes = mem_cgroup_files,
         .early_init = 0,
 };
 
@@ -7044,7 +7068,8 @@ __setup("swapaccount=", enable_swap_account);
 
 static void __init memsw_file_init(void)
 {
-        WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files));
+        WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
+                                          memsw_cgroup_files));
 }
 
 static void __init enable_swap_cgroup(void)