From 13d2f7910ca46234c7973065ad9a12cbcf027120 Mon Sep 17 00:00:00 2001
From: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Date: Tue, 5 Nov 2013 16:55:40 +1100
Subject: [PATCH] 
 mm-sparsemem-fix-a-bug-in-free_map_bootmem-when-config_sparsemem_vmemmap-v2

v2: Fix a bug introduced in v1 patch. Thanks wanpeng!

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/sparse.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 908c13435627..8cc7be0e9590 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -651,10 +651,11 @@ static void __kfree_section_memmap(struct page *memmap)
 static void free_map_bootmem(struct page *memmap)
 {
 	unsigned long maps_section_nr, removing_section_nr, i;
-	unsigned long magic;
+	unsigned long magic, nr_pages;
 	struct page *page = virt_to_page(memmap);
-	unsigned long nr_pages = get_order(sizeof(struct page) *
-					   PAGES_PER_SECTION);
+
+	nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
+		>> PAGE_SHIFT;
 
 	for (i = 0; i < nr_pages; i++, page++) {
 		magic = (unsigned long) page->lru.next;
-- 
2.39.5