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Date: Mon, 22 May 2017 14:36:02 +0100 From: Punit Agrawal <punit.agrawal@....com> To: akpm@...ux-foundation.org Cc: Punit Agrawal <punit.agrawal@....com>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, catalin.marinas@....com, will.deacon@....com, n-horiguchi@...jp.nec.com, kirill.shutemov@...ux.intel.com, mike.kravetz@...cle.com, steve.capper@....com, mark.rutland@....com, hillf.zj@...baba-inc.com, linux-arch@...r.kernel.org, aneesh.kumar@...ux.vnet.ibm.com, Martin Schwidefsky <schwidefsky@...ibm.com>, Heiko Carstens <heiko.carstens@...ibm.com>, Arnd Bergmann <arnd@...db.de> Subject: [PATCH v3 4/6] mm/hugetlb: Allow architectures to override huge_pte_clear() When unmapping a hugepage range, huge_pte_clear() is used to clear the page table entries that are marked as not present. huge_pte_clear() internally just ends up calling pte_clear() which does not correctly deal with hugepages consisting of contiguous page table entries. Add a size argument to address this issue and allow architectures to override huge_pte_clear() in subsequent patches by making it a weak function. Update the s390 to use the new mechanism to override huge_pte_clear(). Note that the change only affects huge_pte_clear() - the other generic hugetlb functions don't need any change. Signed-off-by: Punit Agrawal <punit.agrawal@....com> Cc: Martin Schwidefsky <schwidefsky@...ibm.com> Cc: Heiko Carstens <heiko.carstens@...ibm.com> Cc: Arnd Bergmann <arnd@...db.de> Cc: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com> Cc: Mike Kravetz <mike.kravetz@...cle.com> --- arch/s390/include/asm/hugetlb.h | 10 ++-------- arch/s390/mm/hugetlbpage.c | 9 +++++++++ include/asm-generic/hugetlb.h | 7 ++----- mm/hugetlb.c | 8 +++++++- 4 files changed, 20 insertions(+), 14 deletions(-) diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h index cd546a245c68..aa8489c07f24 100644 --- a/arch/s390/include/asm/hugetlb.h +++ b/arch/s390/include/asm/hugetlb.h @@ -38,14 +38,8 @@ static inline int prepare_hugepage_range(struct file *file, #define arch_clear_hugepage_flags(page) do { } while (0) -static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr, - pte_t *ptep) -{ - if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) - pte_val(*ptep) = _REGION3_ENTRY_EMPTY; - else - pte_val(*ptep) = _SEGMENT_ENTRY_EMPTY; -} +void huge_pte_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned long sz); static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index ae23afc18493..48e19b324017 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -144,6 +144,15 @@ pte_t huge_ptep_get(pte_t *ptep) return __rste_to_pte(pte_val(*ptep)); } +void huge_pte_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned long sz) +{ + if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) + pte_val(*ptep) = _REGION3_ENTRY_EMPTY; + else + pte_val(*ptep) = _SEGMENT_ENTRY_EMPTY; +} + pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h index 99b490b4d05a..3138e126f43b 100644 --- a/include/asm-generic/hugetlb.h +++ b/include/asm-generic/hugetlb.h @@ -31,10 +31,7 @@ static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot) return pte_modify(pte, newprot); } -static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr, - pte_t *ptep) -{ - pte_clear(mm, addr, ptep); -} +void huge_pte_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned long sz); #endif /* _ASM_GENERIC_HUGETLB_H */ diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0e4d1fb3122f..2b0f6f96f2c1 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3289,6 +3289,12 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, return ret; } +void __weak huge_pte_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned long sz) +{ + pte_clear(mm, addr, ptep); +} + void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page) @@ -3338,7 +3344,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, * unmapped and its refcount is dropped, so just clear pte here. */ if (unlikely(!pte_present(pte))) { - huge_pte_clear(mm, address, ptep); + huge_pte_clear(mm, address, ptep, sz); spin_unlock(ptl); continue; } -- 2.11.0
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