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authorBalbir Singh <balbir@linux.vnet.ibm.com>2008-02-07 00:14:18 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-07 08:42:20 -0800
commitac44d354d5c9ced49b1165d6496f134501134219 (patch)
treebe054e8e2d37739a33d94cc78db3fd65e73c3aff /mm/memcontrol.c
parent217bc3194d57150549e9234e6ddfee30de28cc78 (diff)
Memory controller use rcu_read_lock() in mem_cgroup_cache_charge()
Hugh Dickins noticed that we were using rcu_dereference() without rcu_read_lock() in the cache charging routine. The patch below fixes this problem Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.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.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 975e89935d52..160101a05b4d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -456,16 +456,20 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
+ int ret = 0;
struct mem_cgroup *mem;
if (!mm)
mm = &init_mm;
+ rcu_read_lock();
mem = rcu_dereference(mm->mem_cgroup);
+ css_get(&mem->css);
+ rcu_read_unlock();
if (mem->control_type == MEM_CGROUP_TYPE_ALL)
- return mem_cgroup_charge_common(page, mm, gfp_mask,
+ ret = mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE);
- else
- return 0;
+ css_put(&mem->css);
+ return ret;
}
/*