From: Nitin Gupta <nitin.m.gu...@oracle.com>

[ Upstream commit a8e654f01cb725d0bfd741ebca1bf4c9337969cc ]

It's required to avoid losing dirty and accessed bits.

[a...@linux-foundation.org: add a `do' to the do-while loop]
Link: 
http://lkml.kernel.org/r/20171213105756.69879-9-kirill.shute...@linux.intel.com
Signed-off-by: Nitin Gupta <nitin.m.gu...@oracle.com>
Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Cc: David Miller <da...@davemloft.net>
Cc: Vlastimil Babka <vba...@suse.cz>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Michal Hocko <mho...@kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 arch/sparc/include/asm/pgtable_64.h |  2 +-
 arch/sparc/mm/tlb.c                 | 23 ++++++++++++++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/sparc/include/asm/pgtable_64.h 
b/arch/sparc/include/asm/pgtable_64.h
index b6802b978140..81ad06a1672f 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -952,7 +952,7 @@ void update_mmu_cache_pmd(struct vm_area_struct *vma, 
unsigned long addr,
                          pmd_t *pmd);
 
 #define __HAVE_ARCH_PMDP_INVALIDATE
-extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
                            pmd_t *pmdp);
 
 #define __HAVE_ARCH_PGTABLE_DEPOSIT
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index c56a195c9071..b2722ed31053 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -219,17 +219,28 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
        }
 }
 
+static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
+               unsigned long address, pmd_t *pmdp, pmd_t pmd)
+{
+       pmd_t old;
+
+       do {
+               old = *pmdp;
+       } while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
+
+       return old;
+}
+
 /*
  * This routine is only called when splitting a THP
  */
-void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
                     pmd_t *pmdp)
 {
-       pmd_t entry = *pmdp;
-
-       pmd_val(entry) &= ~_PAGE_VALID;
+       pmd_t old, entry;
 
-       set_pmd_at(vma->vm_mm, address, pmdp, entry);
+       entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
+       old = pmdp_establish(vma, address, pmdp, entry);
        flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 
        /*
@@ -240,6 +251,8 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned 
long address,
        if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
            !is_huge_zero_page(pmd_page(entry)))
                (vma->vm_mm)->context.thp_pte_count--;
+
+       return old;
 }
 
 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
-- 
2.15.1

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