[PATCH -V9 04/20] mm/THP: withdraw the pgtable after pmdp related operations

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>

For architectures like ppc64 we look at deposited pgtable when
calling pmdp_get_and_clear. So do the pgtable_trans_huge_withdraw
after finishing pmdp related operations.

Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/huge_memory.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6b785e1..5c4fac2 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1360,9 +1360,15 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		struct page *page;
 		pgtable_t pgtable;
 		pmd_t orig_pmd;
-		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+		/*
+		 * For architectures like ppc64 we look at deposited pgtable
+		 * when calling pmdp_get_and_clear. So do the
+		 * pgtable_trans_huge_withdraw after finishing pmdp related
+		 * operations.
+		 */
 		orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
 		tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
 		if (is_huge_zero_pmd(orig_pmd)) {
 			tlb->mm->nr_ptes--;
 			spin_unlock(&tlb->mm->page_table_lock);
-- 
1.8.1.2