page_cgroup: add helper function to get swap_cgroup

There are multiple places which need to get the swap_cgroup address, so
add a helper function:

  static struct swap_cgroup *swap_cgroup_getsc(swp_entry_t ent,
                                struct swap_cgroup_ctrl **ctrl);

to simplify the code.

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 71a9774e6ead..4c53e971749e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2474,7 +2474,7 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
                         memcg = NULL;
         } else if (PageSwapCache(page)) {
                 ent.val = page_private(page);
-                id = lookup_swap_cgroup(ent);
+                id = lookup_swap_cgroup_id(ent);
                 rcu_read_lock();
                 memcg = mem_cgroup_lookup(id);
                 if (memcg && !css_tryget(&memcg->css))
@@ -5264,7 +5264,7 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma,
         }
         /* There is a swap entry and a page doesn't exist or isn't charged */
         if (ent.val && !ret &&
-                        css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
+                        css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
                 ret = MC_TARGET_SWAP;
                 if (target)
                         target->ent = ent;