userfaultfd: shmem: wire up shmem_mfill_zeropage_pte

For shmem VMAs we can use shmem_mfill_zeropage_pte for UFFDIO_ZEROPAGE

Link: http://lkml.kernel.org/r/1497939652-16528-6-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 48c015c80120bf969ef33ebdfc6f232fd7613224..81192701964d36d609d015ce76cf14dbbb1a0dd9 100644 (file)
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -389,11 +389,13 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
                        err = mfill_zeropage_pte(dst_mm, dst_pmd,
                                                 dst_vma, dst_addr);
        } else {
-               err = -EINVAL; /* if zeropage is true return -EINVAL */
-               if (likely(!zeropage))
+               if (!zeropage)
                        err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd,
                                                     dst_vma, dst_addr,
                                                     src_addr, page);
+               else
+                       err = shmem_mfill_zeropage_pte(dst_mm, dst_pmd,
+                                                      dst_vma, dst_addr);
        }
 
        return err;