From a550e2f5c3a3800889a28fe0a56d6bd9e73fd81d Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Thu, 22 Oct 2015 09:03:45 +1100
Subject: [PATCH] mm, madvise: use vma_is_anonymous() to check for anon VMA

!vma->vm_file is not reliable to detect anon VMA, because not all
drivers bother set it. Let's use vma_is_anonymous() instead.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/madvise.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 38a54267342e..84c29e51e765 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -357,7 +357,7 @@ static int madvise_free_single_vma(struct vm_area_struct *vma,
 		return -EINVAL;
 
 	/* MADV_FREE works for only anon vma at the moment */
-	if (vma->vm_file)
+	if (!vma_is_anonymous(vma))
 		return -EINVAL;
 
 	start = max(vma->vm_start, start_addr);
-- 
2.39.5