From: Christoph Lameter <clameter@sgi.com>
Date: Thu, 27 Mar 2008 04:03:04 +0000 (-0700)
Subject: x86: stricter check in follow_huge_addr()
X-Git-Tag: v2.6.25-rc8~73^2~3
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=25e59881f109dc6378ebc463ae4c2de907435de3;p=linux-2.6-omap-h63xx.git

x86: stricter check in follow_huge_addr()

The first page of the compound page is determined in follow_huge_addr()
but then PageCompound() only checks if the page is part of a compound page.
PageHead() allows checking if this is indeed the first page of the
compound.

Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index 4fbafb4bc2f..0b3d567e686 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -178,7 +178,7 @@ follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 
 	page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
 
-	WARN_ON(!PageCompound(page));
+	WARN_ON(!PageHead(page));
 
 	return page;
 }