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>

diff --git a/mm/shmem.c b/mm/shmem.c
index 47fdeeb..76e971c 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2784,5 +2784,6 @@ 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;
 }