Commit 1d148e21 authored Feb 11, 2015 by Wang, Yalin Committed by Linus Torvalds Feb 11, 2015

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>

parent e4b294c2

include/linux/mm.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -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)

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