mm: fail GFP_DMA allocations when ZONE_DMA is not configured
commita197b59ae6e8bee56fcef37ea2482dc08414e2ac
authorDavid Rientjes <rientjes@google.com>
Wed, 25 May 2011 00:12:35 +0000 (24 17:12 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 25 May 2011 15:39:29 +0000 (25 08:39 -0700)
treeead0890373cc9c36321364efbad73a25898076ab
parentba93fa81b5f2bf0076407a3a777fff122ce16220
mm: fail GFP_DMA allocations when ZONE_DMA is not configured

The page allocator will improperly return a page from ZONE_NORMAL even
when __GFP_DMA is passed if CONFIG_ZONE_DMA is disabled.  The caller
expects DMA memory, perhaps for ISA devices with 16-bit address registers,
and may get higher memory resulting in undefined behavior.

This patch causes the page allocator to return NULL in such circumstances
with a warning emitted to the kernel log on the first occurrence.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc.c