[patch 2/6] mm/page_alloc.c:__alloc_pages_nodemask(): don't alter arg gfp_mask

[akpm@linux-foundation.org]

From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm/page_alloc.c:__alloc_pages_nodemask(): don't alter arg gfp_mask

__alloc_pages_nodemask() strips __GFP_IO when retrying the page
allocation.  But it does this by altering the function-wide variable
gfp_mask.  This will cause subsequent allocation attempts to inadvertently
use the modified gfp_mask.

Cc: Ming Lei <ming.lei@canonical.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff -puN mm/page_alloc.c~mm-page_allocc-__alloc_pages_nodemask-dont-alter-arg-gfp_mask mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_allocc-__alloc_pages_nodemask-dont-alter-arg-gfp_mask
+++ a/mm/page_alloc.c
@@ -2918,8 +2918,9 @@ retry_cpuset:
 		 * can deadlock because I/O on the device might not
 		 * complete.
 		 */
-		gfp_mask = memalloc_noio_flags(gfp_mask);
-		page = __alloc_pages_slowpath(gfp_mask, order,
+		gfp_t mask = memalloc_noio_flags(gfp_mask);
+
+		page = __alloc_pages_slowpath(mask, order,
 				zonelist, high_zoneidx, nodemask,
 				preferred_zone, classzone_idx, migratetype);
 	}
_

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