From 7bb4c628adfb28d83fe65ca895a252f5ec77e477 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@osdl.org>
Date: Thu, 19 Jul 2007 01:49:17 -0700
Subject: [PATCH] --- yaml --- r: 61657 b: refs/heads/master c:
 d688abf50bd5a30d2c44dea2a72dd59052cd3cce h: refs/heads/master i:   61655:
 416e848a51252a17fdaf7500be55fa95c3408274 v: v3

---
 [refs]                           |  2 +-
 trunk/include/linux/page-flags.h | 38 +++++++-------------------------
 trunk/mm/page-writeback.c        |  4 ++++
 3 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/[refs] b/[refs]
index 722f1648fbbc..651e2acbff23 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6819457d2cb7fe4fdb0fc3655b6b6dc71a86bee9
+refs/heads/master: d688abf50bd5a30d2c44dea2a72dd59052cd3cce
diff --git a/trunk/include/linux/page-flags.h b/trunk/include/linux/page-flags.h
index a454176c3e30..209d3a47f50f 100644
--- a/trunk/include/linux/page-flags.h
+++ b/trunk/include/linux/page-flags.h
@@ -189,37 +189,15 @@ static inline void SetPageUptodate(struct page *page)
 #define __SetPagePrivate(page)  __set_bit(PG_private, &(page)->flags)
 #define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
 
+/*
+ * Only test-and-set exist for PG_writeback.  The unconditional operators are
+ * risky: they bypass page accounting.
+ */
 #define PageWriteback(page)	test_bit(PG_writeback, &(page)->flags)
-#define SetPageWriteback(page)						\
-	do {								\
-		if (!test_and_set_bit(PG_writeback,			\
-				&(page)->flags))			\
-			inc_zone_page_state(page, NR_WRITEBACK);	\
-	} while (0)
-#define TestSetPageWriteback(page)					\
-	({								\
-		int ret;						\
-		ret = test_and_set_bit(PG_writeback,			\
-					&(page)->flags);		\
-		if (!ret)						\
-			inc_zone_page_state(page, NR_WRITEBACK);	\
-		ret;							\
-	})
-#define ClearPageWriteback(page)					\
-	do {								\
-		if (test_and_clear_bit(PG_writeback,			\
-				&(page)->flags))			\
-			dec_zone_page_state(page, NR_WRITEBACK);	\
-	} while (0)
-#define TestClearPageWriteback(page)					\
-	({								\
-		int ret;						\
-		ret = test_and_clear_bit(PG_writeback,			\
-				&(page)->flags);			\
-		if (ret)						\
-			dec_zone_page_state(page, NR_WRITEBACK);	\
-		ret;							\
-	})
+#define TestSetPageWriteback(page) test_and_set_bit(PG_writeback,	\
+							&(page)->flags)
+#define TestClearPageWriteback(page) test_and_clear_bit(PG_writeback,	\
+							&(page)->flags)
 
 #define PageBuddy(page)		test_bit(PG_buddy, &(page)->flags)
 #define __SetPageBuddy(page)	__set_bit(PG_buddy, &(page)->flags)
diff --git a/trunk/mm/page-writeback.c b/trunk/mm/page-writeback.c
index 51b3eb6ab445..63512a9ed57e 100644
--- a/trunk/mm/page-writeback.c
+++ b/trunk/mm/page-writeback.c
@@ -987,6 +987,8 @@ int test_clear_page_writeback(struct page *page)
 	} else {
 		ret = TestClearPageWriteback(page);
 	}
+	if (ret)
+		dec_zone_page_state(page, NR_WRITEBACK);
 	return ret;
 }
 
@@ -1012,6 +1014,8 @@ int test_set_page_writeback(struct page *page)
 	} else {
 		ret = TestSetPageWriteback(page);
 	}
+	if (!ret)
+		inc_zone_page_state(page, NR_WRITEBACK);
 	return ret;
 
 }