From b43790eedd31e9535b89bbfa45793919e9504c34 Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov@openvz.org>
Date: Wed, 4 Jun 2014 16:06:42 -0700
Subject: [PATCH] mm: softdirty: don't forget to save file map softdiry bit on
 unmap

pte_file_mksoft_dirty operates with argument passed by a value and
returns modified result thus we need to assign @ptfile here, otherwise
itis a no-op which may lead to loss of the softdirty bit.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/rmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 10aef960d3d0..7da400d5d98e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1361,7 +1361,7 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
 		if (page->index != linear_page_index(vma, address)) {
 			pte_t ptfile = pgoff_to_pte(page->index);
 			if (pte_soft_dirty(pteval))
-				pte_file_mksoft_dirty(ptfile);
+				ptfile = pte_file_mksoft_dirty(ptfile);
 			set_pte_at(mm, address, pte, ptfile);
 		}