[PATCH 2/9] mm: Provide new get_vaddr_frames() helper

[Andrew Morton]

On Wed, 13 May 2015 15:08:08 +0200 Jan Kara <jack at suse.cz> wrote:

> Provide new function get_vaddr_frames().  This function maps virtual
> addresses from given start and fills given array with page frame numbers of
> the corresponding pages. If given start belongs to a normal vma, the function
> grabs reference to each of the pages to pin them in memory. If start
> belongs to VM_IO | VM_PFNMAP vma, we don't touch page structures. Caller
> must make sure pfns aren't reused for anything else while he is using
> them.
> 
> This function is created for various drivers to simplify handling of
> their buffers.
> 
> Acked-by: Mel Gorman <mgorman at suse.de>
> Acked-by: Vlastimil Babka <vbabka at suse.cz>
> Signed-off-by: Jan Kara <jack at suse.cz>
> ---
>  include/linux/mm.h |  44 +++++++++++
>  mm/gup.c           | 226 +++++++++++++++++++++++++++++++++++++++++++++++++++++

That's a lump of new code which many kernels won't be needing.  Can we
put all this in a new .c file and select it within drivers/media
Kconfig?