From 254ab2882a1ef244246b2a3d18c7d1f4b20d1678 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@g5.osdl.org>
Date: Sun, 16 Oct 2005 17:36:06 -0700
Subject: [PATCH] --- yaml --- r: 9902 b: refs/heads/master c:
 3d80636a0d5f056ffc26472d05b6027a7a9f6e1c h: refs/heads/master v: v3

---
 [refs]            |  2 +-
 trunk/mm/vmscan.c | 13 +++++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index f2757c28b024..d4a4f8b5c1ac 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 688ce17b8599abc548b406c00e4d18ae0dec954f
+refs/heads/master: 3d80636a0d5f056ffc26472d05b6027a7a9f6e1c
diff --git a/trunk/mm/vmscan.c b/trunk/mm/vmscan.c
index 0ea71e887bb6..64f9570cff56 100644
--- a/trunk/mm/vmscan.c
+++ b/trunk/mm/vmscan.c
@@ -511,10 +511,11 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
 		 * PageDirty _after_ making sure that the page is freeable and
 		 * not in use by anybody. 	(pagecache + us == 2)
 		 */
-		if (page_count(page) != 2 || PageDirty(page)) {
-			write_unlock_irq(&mapping->tree_lock);
-			goto keep_locked;
-		}
+		if (unlikely(page_count(page) != 2))
+			goto cannot_free;
+		smp_rmb();
+		if (unlikely(PageDirty(page)))
+			goto cannot_free;
 
 #ifdef CONFIG_SWAP
 		if (PageSwapCache(page)) {
@@ -538,6 +539,10 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
 			__pagevec_release_nonlru(&freed_pvec);
 		continue;
 
+cannot_free:
+		write_unlock_irq(&mapping->tree_lock);
+		goto keep_locked;
+
 activate_locked:
 		SetPageActive(page);
 		pgactivate++;