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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2009-01-08 05:08:18 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-08 19:31:07 +0300
commit549927620b04a8f8073ce2ee2a8977f209af2ee5 (patch)
tree6451507892fb353732fe959b2bf0a171fa3ac20b
parenteeee9a8cd1e93c8b94e7788790fa9e2f8910c779 (diff)
downloadlinux-549927620b04a8f8073ce2ee2a8977f209af2ee5.tar.xz
memcg: add null check to page_cgroup_zoneinfo()
If CONFIG_CGROUP_MEM_RES_CTLR_SWAP=y, page_cgroup::mem_cgroup can be NULL. Therefore null checking is better. A later patch uses this function. Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Hugh Dickins <hugh@veritas.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9b4993ee46b3..457d671029b8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -231,6 +231,9 @@ page_cgroup_zoneinfo(struct page_cgroup *pc)
int nid = page_cgroup_nid(pc);
int zid = page_cgroup_zid(pc);
+ if (!mem)
+ return NULL;
+
return mem_cgroup_zoneinfo(mem, nid, zid);
}