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: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/mm/shmem.c b/mm/shmem.c
index eef4ebea51581f9aa8a6d2244f8ce5fa57f99c22..0203cda3297a53f3905521b382045b0e27f01f76 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2701,5 +2701,6 @@ 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;
 }