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Subject: Re: [PATCH 12/21] dma-iommu: factor atomic pool allocations into
 helpers
To:     Christoph Hellwig <hch@lst.de>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20190327080448.5500-1-hch@lst.de>
 <20190327080448.5500-13-hch@lst.de>
 <b3f80a11-1504-e8f9-4438-92bcd5f3df7f@arm.com> <20190410061157.GA5278@lst.de>
 <20190417063358.GA24139@lst.de>
From:   Robin Murphy <robin.murphy@arm.com>
Message-ID: <83615173-a8b4-e0eb-bac3-1a58d61ea4ef@arm.com>
Date:   Thu, 18 Apr 2019 16:06:56 +0100
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On 17/04/2019 07:33, Christoph Hellwig wrote:
> On Wed, Apr 10, 2019 at 08:11:57AM +0200, Christoph Hellwig wrote:
>> On Tue, Apr 09, 2019 at 06:59:32PM +0100, Robin Murphy wrote:
>>> On 27/03/2019 08:04, Christoph Hellwig wrote:
>>>> This keeps the code together and will simplify compiling the code
>>>> out on architectures that are always dma coherent.
>>>
>>> And this is where things take a turn in the direction I just can't get on
>>> with - I'm looking at the final result and the twisty maze of little
>>> disjoint helpers all overlapping each other in functionality is really
>>> difficult to follow. And I would *much* rather have things rely on
>>> compile-time constant optimisation than spend the future having to fix the
>>> #ifdefed parts for arm64 whenever x86-centric changes fail to test them.
>>
>> Can you draft up a patch on top of my series to show me what you
>> want?  I can take care of finishing it up and moving the changes
>> into the right patches in the series.
> 
> Any chance to make some progress on this?  Or at least a better
> description of what you want?

OK, I'm still looking at mmap and get_sgtable, but for now I've pushed 
out a partial branch that consolidates alloc and free in a way which 
makes sense to me:

   git://linux-arm.org/linux-rm  dma/rework

Please let me know what you think.

Robin.