powerpc/mm: update pmdp_invalidate to return old pmd value

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

Link: http://lkml.kernel.org/r/20171213105756.69879-7-kirill.shutemov@linux.intel.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 7 insertions, 4 deletions

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 44697817ccc6..ee19d5bbee06 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1137,8 +1137,8 @@ static inline pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm,
 }
 
 #define __HAVE_ARCH_PMDP_INVALIDATE
-extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
-                            pmd_t *pmdp);
+extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+                             pmd_t *pmdp);
 
 #define __HAVE_ARCH_PMDP_HUGE_SPLIT_PREPARE
 static inline void pmdp_huge_split_prepare(struct vm_area_struct *vma,
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 3b65917785a5..422e80253a33 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -90,16 +90,19 @@ void serialize_against_pte_lookup(struct mm_struct *mm)
  * We use this to invalidate a pmdp entry before switching from a
  * hugepte to regular pmd entry.
  */
-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_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0);
+        unsigned long old_pmd;
+
+        old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0);
         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
         /*
          * This ensures that generic code that rely on IRQ disabling
          * to prevent a parallel THP split work as expected.
          */
         serialize_against_pte_lookup(vma->vm_mm);
+        return __pmd(old_pmd);
 }
 
 static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)