diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index ab27ff7..d6507a6 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -101,7 +101,7 @@
 }
 
 /* __alloc_bootmem...() is protected by !slab_available() */
-int __init_refok init_section_page_cgroup(unsigned long pfn)
+static int __init_refok init_section_page_cgroup(unsigned long pfn)
 {
 	struct mem_section *section;
 	struct page_cgroup *base, *pc;