[PATCH 103/173] shmem: let shared anonymous be nonlinear again

From: Willy Tarreau
Date: Mon Apr 25 2011 - 16:46:55 EST


2.6.27.59-stable review patch. If anyone has any objections, please let us know.

------------------

From: Hugh Dickins <hughd@xxxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

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

--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2691,5 +2691,6 @@ int shmem_zero_setup(struct vm_area_stru
fput(vma->vm_file);
vma->vm_file = file;
vma->vm_ops = &shmem_vm_ops;
+ vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}


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