mm: add gfp mask checking for __get_free_pages()

__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>

1 files changed, 9 insertions, 15 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index afda8fd16484..81926c7ef6f0 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -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)