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

[Jan Kara <jack@suse.cz>]

On Mon 13-07-15 10:45:25, Hans Verkuil wrote:
> 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

I guess Andrew wasn't sure what to push and what not so he just chose the
safe option to not push anything.

> 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.

OK, I'll rebase patches on top of media tree.

								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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> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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