Re: [Hugetlb x86] 3/3 Check p?d_present in huge_pte_offset()

[Adam Litke <agl@us.ibm.com>]

Initial Post (Wed, 17 Aug 2005)

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.

Diffed against 2.6.13-rc6

Signed-off-by: Adam Litke <agl@us.ibm.com>

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