Re: [PATCH 0/9 v5] Helper to abstract vma handling in media layer

From: Jan Kara <jack@suse.cz>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Jan Kara <jack@suse.cz>,
	linux-mm@kvack.org, linux-media@vger.kernel.org,
	dri-devel@lists.freedesktop.org, Pawel Osciak <pawel@osciak.com>,
	Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
	mgorman@suse.de, Marek Szyprowski <m.szyprowski@samsung.com>,
	linux-samsung-soc@vger.kernel.org
Subject: Re: [PATCH 0/9 v5] Helper to abstract vma handling in media layer
Date: Mon, 25 May 2015 15:55:33 +0200	[thread overview]
Message-ID: <20150525135533.GA15663@quack.suse.cz> (raw)
In-Reply-To: <55630994.7040006@xs4all.nl>

On Mon 25-05-15 13:37:56, Hans Verkuil wrote:
> Hi Jan,
> 
> On 05/13/2015 03:08 PM, Jan Kara wrote:
> >   Hello,
> > 
> > I'm sending the fifth version of my patch series to abstract vma handling
> > from the various media drivers. The patches got some review from mm people and
> > testing from device driver guys so unless someone objects, patches will be
> > queued in media tree for the next merge window.
> 
> What is the current status? I saw one comment for patch 9, so I assume it is not
> quite ready yet.
> 
> Let me know when you think it is time to merge.
  There was a minor comment to the exynos patch - I've sent updated version
of that patch as a reply to the comment. Do you want me to resend the whole
series? Otherwise I think you can just pick up the patches and merge them.
Thanks!

								Honza

> > 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).
> > 
> > 								Honza
> > 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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> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR