mm: clear pte in clear_soft_dirty()

As mentioned in the commit 56eecdb912b5 ("mm: Use ptep/pmdp_set_numa()
for updating _PAGE_NUMA bit"), architectures like ppc64 don't do tlb
flush in set_pte/pmd functions.

So when dealing with existing pte in clear_soft_dirty, the pte must be
cleared before being modified.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 288185e2476267169398576d6f6177618b5fedc9..ef44bb474ea2cd33279b001de405674941bba87f 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -792,19 +792,20 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
        pte_t ptent = *pte;
 
        if (pte_present(ptent)) {
+               ptent = ptep_modify_prot_start(vma->vm_mm, addr, pte);
                ptent = pte_wrprotect(ptent);
                ptent = pte_clear_soft_dirty(ptent);
+               ptep_modify_prot_commit(vma->vm_mm, addr, pte, ptent);
        } else if (is_swap_pte(ptent)) {
                ptent = pte_swp_clear_soft_dirty(ptent);
+               set_pte_at(vma->vm_mm, addr, pte, ptent);
        }
-
-       set_pte_at(vma->vm_mm, addr, pte, ptent);
 }
 
 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
                unsigned long addr, pmd_t *pmdp)
 {
-       pmd_t pmd = *pmdp;
+       pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
 
        pmd = pmd_wrprotect(pmd);
        pmd = pmd_clear_soft_dirty(pmd);