From: Hugh Dickins <hughd@google.com>
Date: Tue, 22 Mar 2011 23:33:43 +0000 (-0700)
Subject: shmem: let shared anonymous be nonlinear again
X-Git-Tag: v2.6.35.12~52
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b845a0bebf3e8728277ed92e1cb66e8901cf4b50;p=karo-tx-linux.git

shmem: let shared anonymous be nonlinear again

commit bee4c36a5cf5c9f63ce1d7372aa62045fbd16d47 upstream.

Up to 2.6.22, you could use remap_file_pages(2) on a tmpfs file or a
shared mapping of /dev/zero or a shared anonymous mapping.  In 2.6.23 we
disabled it by default, but set VM_CAN_NONLINEAR to enable it on safe
mappings.  We made sure to set it in shmem_mmap() for tmpfs files, but
missed it in shmem_zero_setup() for the others.  Fix that at last.

Reported-by: Kenny Simpson <theonetruekenny@yahoo.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---

diff --git a/mm/shmem.c b/mm/shmem.c
index f65f84062db5..676eed337809 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2756,5 +2756,6 @@ int shmem_zero_setup(struct vm_area_struct *vma)
 		fput(vma->vm_file);
 	vma->vm_file = file;
 	vma->vm_ops = &shmem_vm_ops;
+	vma->vm_flags |= VM_CAN_NONLINEAR;
 	return 0;
 }