[PATCH] mm: fix __page_mapcount()

From: Kirill A. Shutemov
Date: Wed Nov 11 2015 - 05:10:12 EST


I made mistake in uninlining patch: we need to read _mapcount of the
page which caller pointed us to, not head page.

It's fixlet for
"mm: uninline slowpath of page_mapcount()"

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/util.c b/mm/util.c
index 22dae03a4ae1..5be2a4bdf76b 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -411,8 +411,8 @@ int __page_mapcount(struct page *page)
{
int ret;

- page = compound_head(page);
ret = atomic_read(&page->_mapcount) + 1;
+ page = compound_head(page);
ret += atomic_read(compound_mapcount_ptr(page)) + 1;
if (PageDoubleMap(page))
ret--;
--
2.6.2

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