[patch 040/220] hugetlb: check p?d_present in huge_pte_offset()

[patch 040/220] hugetlb: check p?d_present in huge_pte_offset()

[akpm]

From: Adam Litke <agl@us.ibm.com>

For demand faulting, we cannot assume that the page tables will be
populated.  Do what the rest of the architectures do and test p?d_present()
while walking down the page table.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: <linux-mm@kvack.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 arch/i386/mm/hugetlbpage.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff -puN arch/i386/mm/hugetlbpage.c~hugetlb-check-pd_present-in-huge_pte_offset arch/i386/mm/hugetlbpage.c
--- devel/arch/i386/mm/hugetlbpage.c~hugetlb-check-pd_present-in-huge_pte_offset	2005-09-03 15:46:14.000000000 -0700
+++ devel-akpm/arch/i386/mm/hugetlbpage.c	2005-09-03 15:52:25.000000000 -0700
@@ -46,8 +46,11 @@ pte_t *huge_pte_offset(struct mm_struct 
 	pmd_t *pmd = NULL;
 
 	pgd = pgd_offset(mm, addr);
-	pud = pud_offset(pgd, addr);
-	pmd = pmd_offset(pud, addr);
+	if (pgd_present(*pgd)) {
+		pud = pud_offset(pgd, addr);
+		if (pud_present(*pud))
+			pmd = pmd_offset(pud, addr);
+	}
 	return (pte_t *) pmd;
 }
 
_
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