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Subject[PATCH v2 1/2] mm: add helpers pmdp_modify_prot_start/commit
Date
Introduce helpers pmdp_modify_prot_start/commit to abstract
pmdp_modify_prot transaction. Helpers pmdp_modify_prot_start/commit are
functionally unchanged.

Signed-off-by: Xuefeng Wang <wxf.wang@hisilicon.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
include/asm-generic/pgtable.h | 35 +++++++++++++++++++++++++++++++++++
mm/huge_memory.c | 19 ++++++++-----------
2 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 798ea36a0549..e81bd58a9170 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -673,6 +673,41 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
__ptep_modify_prot_commit(vma, addr, ptep, pte);
}
#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
+
+static inline pmd_t __pmdp_modify_prot_start(struct vm_area_struct *vma,
+ unsigned long addr,
+ pmd_t *pmdp)
+{
+ return pmdp_invalidate(vma, addr, pmdp);
+}
+
+static inline void __pmdp_modify_prot_commit(struct vm_area_struct *vma,
+ unsigned long addr,
+ pmd_t *pmdp, pmd_t pmd)
+{
+ set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#ifndef __HAVE_ARCH_PMDP_MODIFY_PROT_TRANSACTION
+static inline pmd_t pmdp_modify_prot_start(struct vm_area_struct *vma,
+ unsigned long addr,
+ pmd_t *pmdp)
+{
+ __pmdp_modify_prot_start(vma, addr, pmdp);
+}
+#endif /* __HAVE_ARCH_PMDP_MODIFY_PROT_TRANSACTION */
+
+/*
+ * Commit an update to a pmd.
+ */
+static inline void pmdp_modify_prot_commit(struct vm_area_struct *vma,
+ unsigned long addr,
+ pmd_t *pmdp, pmd_t old_pmd, pmd_t pmd)
+{
+ __pmdp_modify_prot_commit(vma, addr, pmdp, pmd);
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif /* CONFIG_MMU */

/*
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a88093213674..53515a3c91dd 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1933,9 +1933,8 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, pgprot_t newprot, int prot_numa)
{
- struct mm_struct *mm = vma->vm_mm;
spinlock_t *ptl;
- pmd_t entry;
+ pmd_t pmdnt, oldpmd;
bool preserve_write;
int ret;

@@ -1961,7 +1960,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
newpmd = swp_entry_to_pmd(entry);
if (pmd_swp_soft_dirty(*pmd))
newpmd = pmd_swp_mksoft_dirty(newpmd);
- set_pmd_at(mm, addr, pmd, newpmd);
+ set_pmd_at(vma->vm_mm, addr, pmd, newpmd);
}
goto unlock;
}
@@ -1995,18 +1994,16 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
*
* The race makes MADV_DONTNEED miss the huge pmd and don't clear it
* which may break userspace.
- *
- * pmdp_invalidate() is required to make sure we don't miss
- * dirty/young flags set by hardware.
*/
- entry = pmdp_invalidate(vma, addr, pmd);

- entry = pmd_modify(entry, newprot);
+ oldpmd = pmdp_modify_prot_start(vma, addr, pmd);
+ pmdnt = pmd_modify(oldpmd, newprot);
if (preserve_write)
- entry = pmd_mk_savedwrite(entry);
+ pmdnt = pmd_mk_savedwrite(pmdnt);
+ pmdp_modify_prot_commit(vma, addr, pmd, oldpmd, pmdnt);
+
ret = HPAGE_PMD_NR;
- set_pmd_at(mm, addr, pmd, entry);
- BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry));
+ BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(pmdnt));
unlock:
spin_unlock(ptl);
return ret;
--
2.17.1

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