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

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Message-Id: <1418746691-326-3-git-send-email-hannes@cmpxchg.org>
Date:	Tue, 16 Dec 2014 11:18:10 -0500
From:	Johannes Weiner <hannes@...xchg.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Tejun Heo <tj@...nel.org>, Hugh Dickins <hughd@...gle.com>,
	Michel Lespinasse <walken@...gle.com>, Jan Kara <jack@...e.cz>,
	"Kirill A. Shutemov" <kirill@...temov.name>, linux-mm@...ck.org,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [patch 2/3] 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@...xchg.org>
Reviewed-by: Jan Kara <jack@...e.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 mm/memory.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 4c06cdcd36cf..d5a303cf2901 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2155,9 +2155,7 @@ 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) {
@@ -3013,8 +3011,7 @@ 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

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