From: Bill Burns <bburns@redhat.com>
Date: Thu, 21 Aug 2008 13:09:10 -0400
Subject: [xen] fix building with max_phys_cpus=128
Message-id: 20080821170910.9528.18187.sendpatchset@localhost.localdomain
O-Subject: [RHEL5.3 PATCH 1/3] Xen fix building with max_phys_cpus=128
Bugzilla: 447958
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Chris Lalancette <clalance@redhat.com>

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1218632057 -3600
# Node ID c6402709acc8122e3f8f92a885750afb4061ac61
# Parent  0638a5c2cc9f2053f6025edf3ddc5ff12300924d
shadow: Fix BUILD_BUG_ON().
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

Fixes bz 447958

There were two issues with this. First was a build
failure due to the size of the page_info structure
growing to be larger than the shadow_page_info structure.
Thus was due to the larger cpu mask field needed in
the page_info structure. A "build bug" macro needed
to be changed to allow this. This change has been
made upstream.

diff --git a/arch/x86/mm/shadow/private.h b/arch/x86/mm/shadow/private.h
index 962d096..3ca5b58 100644
--- a/arch/x86/mm/shadow/private.h
+++ b/arch/x86/mm/shadow/private.h
@@ -245,15 +245,14 @@ struct shadow_page_info
     };
 };
 
-/* The structure above *must* be the same size as a struct page_info
+/* The structure above *must* be no larger than a struct page_info
  * from mm.h, since we'll be using the same space in the frametable. 
  * Also, the mbz field must line up with the owner field of normal 
  * pages, so they look properly like anonymous/xen pages. */
 static inline void shadow_check_page_struct_offsets(void) {
-    BUILD_BUG_ON(sizeof (struct shadow_page_info) 
-                 != sizeof (struct page_info));
-    BUILD_BUG_ON(offsetof(struct shadow_page_info, mbz) 
-                 != offsetof(struct page_info, u.inuse._domain));
+    BUILD_BUG_ON(sizeof (struct shadow_page_info) > sizeof (struct page_info));
+    BUILD_BUG_ON(offsetof(struct shadow_page_info, mbz) !=
+                 offsetof(struct page_info, u.inuse._domain));
 };
 
 /* Shadow type codes */