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| author | Wang, Yalin <Yalin.Wang@sonymobile.com> | 2015-02-11 15:24:48 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-11 17:06:00 -0800 |
| commit | 1d148e218a0d0566b1c06f2f45f1436d53b049b2 (patch) | |
| tree | 39e416568334e656764c3a5eab0b5939f6121779 | |
| parent | e4b294c2d8f73af4cd41ff30638ad0e4769dc56a (diff) | |
| download | linux-1d148e218a0d0566b1c06f2f45f1436d53b049b2.tar.bz2 | |
mm: add VM_BUG_ON_PAGE() to page_mapcount()
Add VM_BUG_ON_PAGE() for slab pages. _mapcount is an union with slab
struct in struct page, so we must avoid accessing _mapcount if this page
is a slab page. Also remove the unneeded bracket.
Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/mm.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 8dd4fde9d2e5..c6bf813a6b3d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -484,7 +484,8 @@ static inline void page_mapcount_reset(struct page *page) static inline int page_mapcount(struct page *page) { - return atomic_read(&(page)->_mapcount) + 1; + VM_BUG_ON_PAGE(PageSlab(page), page); + return atomic_read(&page->_mapcount) + 1; } static inline int page_count(struct page *page) |