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 4fbafb4bc2f02a93bfcbb64fa732fc08fb0af406..0b3d567e686df15c1b042deb388091ab78a6ae25 100644 (file)
--- 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;
 }