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

Hans Verkuil hverkuil at xs4all.nl
Mon Jun 1 06:02:14 PDT 2015

On 06/01/2015 02:40 PM, Jan Kara wrote:
> On Thu 28-05-15 16:24:02, Andrew Morton wrote:
>> 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?
>   Yeah, makes sense. I'll write a patch. Hans, is it OK with you if I
> just create a patch on top of the series you have in your tree?

No problem.



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