[RFC PATCH 1/3] powerpc/mm: update pmdp_invalidate to return old pmd value

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 4 ++--
 arch/powerpc/mm/pgtable-book3s64.c           | 9 ++++++---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 41d484ac0822..ece6912fae8e 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1119,8 +1119,8 @@ 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..0bb7f824ecdd 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)
+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)
-- 
2.13.3