From: Punit Agrawal <punit.agrawal@arm.com>
To: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Punit Agrawal <punit.agrawal@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Tyler Baicar <tbaicar@codeaurora.org>,
David Woods <dwoods@mellanox.com>
Subject: [RFC PATCH 2/2] arm64: hugetlbpages: Correctly handle swap entries in huge_pte_offset()
Date: Thu, 23 Mar 2017 12:58:23 +0000 [thread overview]
Message-ID: <20170323125823.429-3-punit.agrawal@arm.com> (raw)
In-Reply-To: <20170323125823.429-1-punit.agrawal@arm.com>
huge_pte_offset() does not correctly handle poisoned or migration page
table entries. Not knowing the size of the hugepage entry being
requested only compounded the problem.
The recently added hstate parameter can be used to determine the size of
hugepage being accessed. Use the size to find the correct page table
entry to return when coming across a swap page table entry.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: David Woods <dwoods@mellanox.com>
---
arch/arm64/mm/hugetlbpage.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 75d8cc3e138b..db108fa6e197 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -191,38 +191,39 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, struct hstate *h)
{
+ unsigned long sz = huge_page_size(h);
pgd_t *pgd;
pud_t *pud;
- pmd_t *pmd = NULL;
- pte_t *pte = NULL;
+ pmd_t *pmd;
+ pte_t *pte;
pgd = pgd_offset(mm, addr);
pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);
if (!pgd_present(*pgd))
return NULL;
+
pud = pud_offset(pgd, addr);
- if (!pud_present(*pud))
+ if (pud_none(*pud) && sz != PUD_SIZE)
return NULL;
-
- if (pud_huge(*pud))
+ else if (!pud_table(*pud))
return (pte_t *)pud;
+
+ if (sz == CONT_PMD_SIZE)
+ addr &= CONT_PMD_MASK;
+
pmd = pmd_offset(pud, addr);
- if (!pmd_present(*pmd))
+ if (pmd_none(*pmd) &&
+ !(sz == PMD_SIZE || sz == CONT_PMD_SIZE))
return NULL;
-
- if (pte_cont(pmd_pte(*pmd))) {
- pmd = pmd_offset(
- pud, (addr & CONT_PMD_MASK));
- return (pte_t *)pmd;
- }
- if (pmd_huge(*pmd))
+ else if (!pmd_table(*pmd))
return (pte_t *)pmd;
- pte = pte_offset_kernel(pmd, addr);
- if (pte_present(*pte) && pte_cont(*pte)) {
+
+ if (sz == CONT_PTE_SIZE) {
pte = pte_offset_kernel(
pmd, (addr & CONT_PTE_MASK));
return pte;
}
+
return NULL;
}
--
2.11.0
--
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next prev parent reply other threads:[~2017-03-23 12:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-23 12:58 [RFC PATCH 0/2] Add hstate parameter to huge_pte_offset() Punit Agrawal
2017-03-23 12:58 ` [RFC PATCH 1/2] mm/hugetlb.c: add " Punit Agrawal
2017-03-23 12:58 ` Punit Agrawal [this message]
2017-03-23 20:55 ` [RFC PATCH 0/2] Add " Mike Kravetz
2017-03-24 10:37 ` Kirill A. Shutemov
2017-03-24 11:23 ` Punit Agrawal
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