From dab0a7746190acc10f1576a6287d190474f20930 Mon Sep 17 00:00:00 2001
From: Hartmut Birr <osexpert@googlemail.com>
Date: Fri, 30 Jan 2004 23:57:58 +0000
Subject: [PATCH] - Check for a privat page and change only the page protection
   for such a page in MmAccessFaultSectionView.

svn path=/trunk/; revision=7932
---
 reactos/ntoskrnl/mm/section.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/reactos/ntoskrnl/mm/section.c b/reactos/ntoskrnl/mm/section.c
index acd41d4029d..a591a29f47c 100644
--- a/reactos/ntoskrnl/mm/section.c
+++ b/reactos/ntoskrnl/mm/section.c
@@ -16,7 +16,7 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
-/* $Id: section.c,v 1.142 2004/01/27 20:13:08 hbirr Exp $
+/* $Id: section.c,v 1.143 2004/01/30 23:57:58 hbirr Exp $
  *
  * PROJECT:         ReactOS kernel
  * FILE:            ntoskrnl/mm/section.c
@@ -1218,6 +1218,7 @@ MmAccessFaultSectionView(PMADDRESS_SPACE AddressSpace,
   ULONG Offset;
   PMM_PAGEOP PageOp;
   PMM_REGION Region;
+  ULONG Entry;
 
   /*
    * Check if the page has been paged out or has already been set readwrite
@@ -1253,15 +1254,11 @@ MmAccessFaultSectionView(PMADDRESS_SPACE AddressSpace,
     */
    MmLockSectionSegment(Segment);
 
-   /*
-    * Sanity check.
-    */
-   if (MmGetPageEntrySectionSegment(Segment, Offset) == 0)
-     {
-       DPRINT1("COW fault for page with PESS 0. Address was 0x%.8X\n",
-	       Address);
-     }
+   OldPage = MmGetPhysicalAddressForProcess(NULL, Address);
+   Entry = MmGetPageEntrySectionSegment(Segment, Offset);
+
    MmUnlockSectionSegment(Segment);
+
    /*
     * Check if we are doing COW
     */
@@ -1273,6 +1270,18 @@ MmAccessFaultSectionView(PMADDRESS_SPACE AddressSpace,
        return(STATUS_UNSUCCESSFUL);
      }
 
+   if (IS_SWAP_FROM_SSE(Entry) ||
+       PAGE_FROM_SSE(Entry) != OldPage.u.LowPart)
+     {
+       /* This is a private page. We must only change the page protection. */
+       MmSetPageProtect(AddressSpace->Process, (PVOID)PAddress, Region->Protect);
+       if (Locked)
+         {
+	   MmLockPage(OldPage);
+	 }
+       return(STATUS_SUCCESS);
+     }
+
    /*
     * Get or create a pageop
     */
@@ -1330,7 +1339,6 @@ MmAccessFaultSectionView(PMADDRESS_SPACE AddressSpace,
    /*
     * Copy the old page
     */
-   OldPage = MmGetPhysicalAddressForProcess(NULL, Address);
 
    NewAddress = ExAllocatePageWithPhysPage(NewPage);
    memcpy(NewAddress, (PVOID)PAddress, PAGE_SIZE);