From: Hugh Dickins <hugh@veritas.com>
Date: Sat, 16 Jun 2007 17:15:59 +0000 (-0700)
Subject: i386 mm: use pte_update() in ptep_test_and_clear_dirty()
X-Git-Tag: v2.6.22-rc5~17
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d6f8bb1310d4745ff1d0c74eeacae31e2a3eeff1;p=linux-2.6

i386 mm: use pte_update() in ptep_test_and_clear_dirty()

It is not safe to use pte_update_defer() in ptep_test_and_clear_young():
its only user, /proc/<pid>/clear_refs, drops pte lock before flushing TLB.
Use the safe though less efficient pte_update() paravirtop in its place.
Likewise in ptep_test_and_clear_dirty(), though that has no current use.

These are macros (header file dependency stops them from becoming inline
functions), so be more liberal with the underscores and parentheses.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index 2394589786..d62bdb029e 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -295,22 +295,24 @@ do {									\
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 #define ptep_test_and_clear_dirty(vma, addr, ptep) ({			\
-	int ret = 0;							\
-	if (pte_dirty(*ptep))						\
-		ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); \
-	if (ret)							\
-		pte_update_defer(vma->vm_mm, addr, ptep);		\
-	ret;								\
+	int __ret = 0;							\
+	if (pte_dirty(*(ptep)))						\
+		__ret = test_and_clear_bit(_PAGE_BIT_DIRTY,		\
+						&(ptep)->pte_low);	\
+	if (__ret)							\
+		pte_update((vma)->vm_mm, addr, ptep);			\
+	__ret;								\
 })
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define ptep_test_and_clear_young(vma, addr, ptep) ({			\
-	int ret = 0;							\
-	if (pte_young(*ptep))						\
-		ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); \
-	if (ret)							\
-		pte_update_defer(vma->vm_mm, addr, ptep);		\
-	ret;								\
+	int __ret = 0;							\
+	if (pte_young(*(ptep)))						\
+		__ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,		\
+						&(ptep)->pte_low);	\
+	if (__ret)							\
+		pte_update((vma)->vm_mm, addr, ptep);			\
+	__ret;								\
 })
 
 /*