memcg: make cgroup_event deal with mem_cgroup instead of cgroup_subsys_state

cgroup_event is now memcg specific.  Replace cgroup_event->css with
->memcg and convert [un]register_event() callbacks to take mem_cgroup
pointer instead of cgroup_subsys_state one.  This simplifies the code
slightly and makes css_to_vmpressure() unnecessary which is removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>

1 files changed, 6 insertions, 6 deletions

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index 0f25a996d150..196970a4541f 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -278,7 +278,7 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
 
 /**
  * vmpressure_register_event() - Bind vmpressure notifications to an eventfd
- * @css:        css that is interested in vmpressure notifications
+ * @memcg:      memcg that is interested in vmpressure notifications
  * @eventfd:    eventfd context to link notifications with
  * @args:       event arguments (used to set up a pressure level threshold)
  *
@@ -290,10 +290,10 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
  *
  * To be used as memcg event method.
  */
-int vmpressure_register_event(struct cgroup_subsys_state *css,
+int vmpressure_register_event(struct mem_cgroup *memcg,
                               struct eventfd_ctx *eventfd, const char *args)
 {
-        struct vmpressure *vmpr = css_to_vmpressure(css);
+        struct vmpressure *vmpr = memcg_to_vmpressure(memcg);
         struct vmpressure_event *ev;
         int level;
 
@@ -321,7 +321,7 @@ int vmpressure_register_event(struct cgroup_subsys_state *css,
 
 /**
  * vmpressure_unregister_event() - Unbind eventfd from vmpressure
- * @css:        css handle
+ * @memcg:      memcg handle
  * @eventfd:    eventfd context that was used to link vmpressure with the @cg
  *
  * This function does internal manipulations to detach the @eventfd from
@@ -330,10 +330,10 @@ int vmpressure_register_event(struct cgroup_subsys_state *css,
  *
  * To be used as memcg event method.
  */
-void vmpressure_unregister_event(struct cgroup_subsys_state *css,
+void vmpressure_unregister_event(struct mem_cgroup *memcg,
                                  struct eventfd_ctx *eventfd)
 {
-        struct vmpressure *vmpr = css_to_vmpressure(css);
+        struct vmpressure *vmpr = memcg_to_vmpressure(memcg);
         struct vmpressure_event *ev;
 
         mutex_lock(&vmpr->events_lock);