[PATCH] [222/275] shmem: let shared anonymous be nonlinear again

From: Andi Kleen
Date: Wed Mar 30 2011 - 17:22:47 EST


2.6.35-longterm review patch. If anyone has any objections, please let me 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>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

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

Index: linux-2.6.35.y/mm/shmem.c
===================================================================
--- linux-2.6.35.y.orig/mm/shmem.c 2011-03-29 22:50:27.900544514 -0700
+++ linux-2.6.35.y/mm/shmem.c 2011-03-29 23:03:02.862226932 -0700
@@ -2756,5 +2756,6 @@
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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