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mm: add gfp mask checking for __get_free_pages()

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__get_free_pages() with __GFP_HIGHMEM is not safe because the return
address cannot represent a highmem page.  get_zeroed_page() already has
such a debug checking.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2009-09-21 17:01:47 -07:00 committed by Linus Torvalds
parent a26f5320c4
commit 945a11136e
1 changed files with 9 additions and 15 deletions
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24
mm/page_alloc.c
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@ -1922,31 +1922,25 @@ EXPORT_SYMBOL(__alloc_pages_nodemask);
*/
unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
{
struct page * page;
struct page *page;
/*
* __get_free_pages() returns a 32-bit address, which cannot represent
* a highmem page
*/
VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
page = alloc_pages(gfp_mask, order);
if (!page)
return 0;
return (unsigned long) page_address(page);
}
EXPORT_SYMBOL(__get_free_pages);
unsigned long get_zeroed_page(gfp_t gfp_mask)
{
struct page * page;
/*
* get_zeroed_page() returns a 32-bit address, which cannot represent
* a highmem page
*/
VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
if (page)
return (unsigned long) page_address(page);
return 0;
return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
}
EXPORT_SYMBOL(get_zeroed_page);
void __pagevec_free(struct pagevec *pvec)