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Commit d2a1a1f0 authored by Yu Zhao's avatar Yu Zhao Committed by Linus Torvalds
Browse files

mm: use unsigned long constant for page flags 

struct page->flags is unsigned long, so when shifting bits we should use
UL suffix to match it.

Found this problem after I added 64-bit CPU specific page flags and
failed to compile the kernel:

  mm/page_alloc.c: In function '__free_one_page':
  mm/page_alloc.c:672:2: error: integer overflow in expression [-Werror=overflow]

Link: http://lkml.kernel.org/r/1461971723-16187-1-git-send-email-yuzhao@google.com


Signed-off-by: default avatarYu Zhao <yuzhao@google.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2a138dc7

include/linux/page-flags.h

+9 −9
Original line number Diff line number Diff line
@@ -479,7 +479,7 @@ static inline void ClearPageCompound(struct page *page) 
}

#endif



#define PG_head_mask ((1L << PG_head))

#define PG_head_mask ((1UL << PG_head))



#ifdef CONFIG_HUGETLB_PAGE

int PageHuge(struct page *page);
@@ -670,7 +670,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page) 
}



#ifdef CONFIG_MMU

#define __PG_MLOCKED		(1 << PG_mlocked)

#define __PG_MLOCKED		(1UL << PG_mlocked)

#else

#define __PG_MLOCKED		0

#endif
@@ -680,11 +680,11 @@ static inline void ClearPageSlabPfmemalloc(struct page *page) 
 * these flags set.  It they are, there is a problem.

 */

#define PAGE_FLAGS_CHECK_AT_FREE \

	(1 << PG_lru	 | 1 << PG_locked    | \

	 1 << PG_private | 1 << PG_private_2 | \

	 1 << PG_writeback | 1 << PG_reserved | \

	 1 << PG_slab	 | 1 << PG_swapcache | 1 << PG_active | \

	 1 << PG_unevictable | __PG_MLOCKED)

	(1UL << PG_lru	 | 1UL << PG_locked    | \

	 1UL << PG_private | 1UL << PG_private_2 | \

	 1UL << PG_writeback | 1UL << PG_reserved | \

	 1UL << PG_slab	 | 1UL << PG_swapcache | 1UL << PG_active | \

	 1UL << PG_unevictable | __PG_MLOCKED)



/*

 * Flags checked when a page is prepped for return by the page allocator.
@@ -695,10 +695,10 @@ static inline void ClearPageSlabPfmemalloc(struct page *page) 
 * alloc-free cycle to prevent from reusing the page.

 */

#define PAGE_FLAGS_CHECK_AT_PREP	\

	(((1 << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)

	(((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)



#define PAGE_FLAGS_PRIVATE				\

	(1 << PG_private | 1 << PG_private_2)

	(1UL << PG_private | 1UL << PG_private_2)

/**

 * page_has_private - Determine if page has private stuff

 * @page: The page to be checked