Re: [PATCH 0/10 v6] Helper to abstract vma handling in media layer

[Hans Verkuil <hverkuil@xs4all.nl>]

On 07/09/2015 02:12 PM, Hans Verkuil wrote:
> On 07/09/2015 01:48 PM, Jan Kara wrote:
>>   Hello,
>>
>>   Hans, did you have a chance to look at these patches? I have tested them
>> with the vivid driver but it would be good if you could run them through
>> your standard testing procedure as well. Andrew has updated the patches in
>> his tree but some ack from you would be welcome...
> 
> I've planned a 'patch day' for Monday. So hopefully you'll see a pull request
> by then.

OK, I'm confused. I thought the non-vb2 patches would go in for 4.2? That didn't
happen, so I guess the plan is to merge the whole lot for 4.3 via our media
tree? If that's the case, can you post a new patch series on top of the master
branch of the media tree? I want to make sure I use the right patches. Also, if
you do make a new patch series, then it would be better if patch 10/10 is folded
into patch 2/10.

If that's not the case, then you have to let me know what I should do.

Regards,

	Hans

>>
>> 								Honza
>> On Thu 18-06-15 16:08:30, Jan Kara wrote:
>>>   Hello,
>>>
>>> I'm sending the sixth version of my patch series to abstract vma handling from
>>> the various media drivers. Since the previous version I have added a patch to
>>> move mm helpers into a separate file and behind a config option. I also
>>> changed patch pushing mmap_sem down in videobuf2 core to avoid lockdep warning
>>> and NULL dereference Hans found in his testing. I've also included small
>>> fixups Andrew was carrying.
>>>
>>> After this patch set drivers have to know much less details about vmas, their
>>> types, and locking. Also quite some code is removed from them. As a bonus
>>> drivers get automatically VM_FAULT_RETRY handling. The primary motivation for
>>> this series is to remove knowledge about mmap_sem locking from as many places a
>>> possible so that we can change it with reasonable effort.
>>>
>>> The core of the series is the new helper get_vaddr_frames() which is given a
>>> virtual address and it fills in PFNs / struct page pointers (depending on VMA
>>> type) into the provided array. If PFNs correspond to normal pages it also grabs
>>> references to these pages. The difference from get_user_pages() is that this
>>> function can also deal with pfnmap, and io mappings which is what the media
>>> drivers need.
>>>
>>> I have tested the patches with vivid driver so at least vb2 code got some
>>> exposure. Conversion of other drivers was just compile-tested (for x86 so e.g.
>>> exynos driver which is only for Samsung platform is completely untested).
>>>
>>> Andrew, can you please update the patches in mm three? Thanks!
>>>
>>> 								Honza
>>>
>>> Changes since v5:
>>> * Moved mm helper into a separate file and behind a config option
>>> * Changed the first patch pushing mmap_sem down in videobuf2 core to avoid
>>>   possible deadlock
>>>
>>> Changes since v4:
>>> * Minor cleanups and fixes pointed out by Mel and Vlasta
>>> * Added Acked-by tags
>>>
>>> Changes since v3:
>>> * Added include <linux/vmalloc.h> into mm/gup.c as it's needed for some archs
>>> * Fixed error path for exynos driver
>>>
>>> Changes since v2:
>>> * Renamed functions and structures as Mel suggested
>>> * Other minor changes suggested by Mel
>>> * Rebased on top of 4.1-rc2
>>> * Changed functions to get pointer to array of pages / pfns to perform
>>>   conversion if necessary. This fixes possible issue in the omap I may have
>>>   introduced in v2 and generally makes the API less errorprone.
> 
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