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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2011-03-23 16:42:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-23 19:46:22 -0700
commit56039efa18f2530fc23e8ef19e716b65ee2a1d1e (patch)
treea61cbd2f760e93363657622de2cd1591db028458 /mm/memcontrol.c
parent6c191cd01a935e5b53ef43c9403c771bb7a32b60 (diff)
memcg: fix ugly initialization of return value is in caller
Remove initialization of vaiable in caller of memory cgroup function. Actually, it's return value of memcg function but it's initialized in caller. Some memory cgroup uses following style to bring the result of start function to the end function for avoiding races. mem_cgroup_start_A(&(*ptr)) /* Something very complicated can happen here. */ mem_cgroup_end_A(*ptr) In some calls, *ptr should be initialized to NULL be caller. But it's ugly. This patch fixes that *ptr is initialized by _start function. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e1ee6ad9c97..b56bd74b486 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2475,7 +2475,7 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
/* shmem */
if (PageSwapCache(page)) {
- struct mem_cgroup *mem = NULL;
+ struct mem_cgroup *mem;
ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
if (!ret)
@@ -2501,6 +2501,8 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
struct mem_cgroup *mem;
int ret;
+ *ptr = NULL;
+
if (mem_cgroup_disabled())
return 0;
@@ -2916,6 +2918,8 @@ int mem_cgroup_prepare_migration(struct page *page,
enum charge_type ctype;
int ret = 0;
+ *ptr = NULL;
+
VM_BUG_ON(PageTransHuge(page));
if (mem_cgroup_disabled())
return 0;
@@ -3058,7 +3062,7 @@ int mem_cgroup_shmem_charge_fallback(struct page *page,
struct mm_struct *mm,
gfp_t gfp_mask)
{
- struct mem_cgroup *mem = NULL;
+ struct mem_cgroup *mem;
int ret;
if (mem_cgroup_disabled())