[PATCH] mm: compaction: Fix return value of capture_free_page

[Mel Gorman]

On Wed, Nov 21, 2012 at 02:21:51PM -0500, Dave Hansen wrote:
> 
> This needs to make it in before 3.7 is released.
> 

This is also required. Dave, can you double check? The surprise is that
this does not blow up very obviously.

---8<---
From: Mel Gorman <mgorman@xxxxxxx>
Subject: [PATCH] mm: compaction: Fix return value of capture_free_page

Commit ef6c5be6 (fix incorrect NR_FREE_PAGES accounting (appears like
memory leak)) fixes a NR_FREE_PAGE accounting leak but missed the return
value which was also missed by this reviewer until today. That return value
is used by compaction when adding pages to a list of isolated free
pages and without this follow-up fix, there is a risk of free list
corruption.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
 mm/page_alloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bcb72c6..8193809 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1422,7 +1422,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
 		}
 	}
 
-	return 1UL << order;
+	return 1UL << alloc_order;
 }
 
 /*
--
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