[patch 2/3] mm: memory: remove ->vm_file check on shared writable vmas

[Johannes Weiner <hannes@cmpxchg.org>]

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>
---
 mm/memory.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 72d998eb0438..5640a718ac58 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2168,9 +2168,7 @@ 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) {
@@ -3026,8 +3024,7 @@ 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;
-- 
2.1.3