memcg: remove mem from arg of charge_common

mem_cgroup_charge_common() is always called with @mem = NULL, so it's
meaningless.  This patch removes it.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 9 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 79a53f0f0cf5..ea5f5edf00b7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2018,10 +2018,9 @@ out:
  * < 0 if the cgroup is over its limit
  */
 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
-                                gfp_t gfp_mask, enum charge_type ctype,
-                                struct mem_cgroup *memcg)
+                                gfp_t gfp_mask, enum charge_type ctype)
 {
-        struct mem_cgroup *mem;
+        struct mem_cgroup *mem = NULL;
         struct page_cgroup *pc;
         int ret;
 
@@ -2031,7 +2030,6 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
                 return 0;
         prefetchw(pc);
 
-        mem = memcg;
         ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
         if (ret || !mem)
                 return ret;
@@ -2059,7 +2057,7 @@ int mem_cgroup_newpage_charge(struct page *page,
         if (unlikely(!mm))
                 mm = &init_mm;
         return mem_cgroup_charge_common(page, mm, gfp_mask,
-                                MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
+                                MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }
 
 static void
@@ -2069,7 +2067,6 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                 gfp_t gfp_mask)
 {
-        struct mem_cgroup *mem = NULL;
         int ret;
 
         if (mem_cgroup_disabled())
@@ -2101,22 +2098,24 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                 unlock_page_cgroup(pc);
         }
 
-        if (unlikely(!mm && !mem))
+        if (unlikely(!mm))
                 mm = &init_mm;
 
         if (page_is_file_cache(page))
                 return mem_cgroup_charge_common(page, mm, gfp_mask,
-                                MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
+                                MEM_CGROUP_CHARGE_TYPE_CACHE);
 
         /* shmem */
         if (PageSwapCache(page)) {
+                struct mem_cgroup *mem = NULL;
+
                 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
                 if (!ret)
                         __mem_cgroup_commit_charge_swapin(page, mem,
                                         MEM_CGROUP_CHARGE_TYPE_SHMEM);
         } else
                 ret = mem_cgroup_charge_common(page, mm, gfp_mask,
-                                        MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
+                                        MEM_CGROUP_CHARGE_TYPE_SHMEM);
 
         return ret;
 }