mm: memory: remove ->vm_file check on shared writable vmas

Shared anonymous mmaps are implemented with shmem files, so all VMAs with
shared writable semantics also have an underlying backing file.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 5 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 9aa09217fe20..0e9b32610655 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2127,9 +2127,7 @@ reuse:
                                 balance_dirty_pages_ratelimited(mapping);
                         }
 
-                        /* file_update_time outside page_lock */
-                        if (vma->vm_file)
-                                file_update_time(vma->vm_file);
+                        file_update_time(vma->vm_file);
                 }
                 put_page(dirty_page);
                 if (page_mkwrite) {
@@ -2971,8 +2969,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                 balance_dirty_pages_ratelimited(mapping);
         }
 
-        /* file_update_time outside page_lock */
-        if (vma->vm_file && !vma->vm_ops->page_mkwrite)
+        if (!vma->vm_ops->page_mkwrite)
                 file_update_time(vma->vm_file);
 
         return ret;