[PATCH] shmem: let shared anonymous be nonlinear again

From: Hugh Dickins
Date: Sun Mar 20 2011 - 01:31:05 EST

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@xxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>

mm/shmem.c | 1 +
1 file changed, 1 insertion(+)

--- 2.6.38/mm/shmem.c 2011-03-14 18:20:32.000000000 -0700
+++ linux/mm/shmem.c 2011-03-19 15:09:26.000000000 -0700
@@ -2791,5 +2791,6 @@ int shmem_zero_setup(struct vm_area_stru
vma->vm_file = file;
vma->vm_ops = &shmem_vm_ops;
+ vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
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