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Date: Wed, 23 Sep 2026 06:51:43 +0200
From: Christoph Hellwig <hch@lst.de>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
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	Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
	Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
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	Benjamin Marzinski <bmarzins@redhat.com>, dm-devel@lists.linux.dev
Subject: Re: [PATCH v6 04/13] block: introduce dma map backed bio type
Message-ID: <20260923045143.GA26231@lst.de>
References: <cover.1789997898.git.asml.silence@gmail.com> <a3ee719abc440ca139f1a945fdaf43a45f0c6b57.1789997898.git.asml.silence@gmail.com> <20260922131610.GA30468@lst.de> <cce62c72-278a-44d1-9cf7-e0beb0b72688@gmail.com>
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On Tue, Sep 22, 2026 at 02:54:25PM +0100, Pavel Begunkov wrote:
>>
>> Can you please expland on the splitting considerations a bit?  Preferably
>> both in a comment for the details, and in the commit log for how we
>> arrived at them and why they are fine for now?
>
> I'll add something to the commit log, but not sure which specific
> details in comments you mean. Do you want me to expand the comment
> above limiting the number of segments? Maybe I should add there that
> it's stricter than necessary and might cause more splitting than
> necessary? This one:

Yes, explain why we apply a relatively arbitrary limit not fully
exploiting the hardware capabilities, and why we thing that is okay.