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Date: Fri, 26 Jun 2026 07:10:04 +0200
From: Christoph Hellwig <hch@lst.de>
To: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Joanne Koong <joannelkoong@gmail.com>, Christoph Hellwig <hch@lst.de>,
	willy@infradead.org, djwong@kernel.org,
	linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [RFC PATCH v1 0/3] iomap: convert to in-iter ->iomap_next()
 model
Message-ID: <20260626051004.GA8968@lst.de>
References: <20260625024723.1611000-1-joannelkoong@gmail.com> <6446cb94-a005-4e4c-8034-d7bf2a4b402b@linux.alibaba.com> <20260625130206.GC22620@lst.de> <4da9a5ac-2a53-4fe2-9283-2e0f6181c248@linux.alibaba.com> <CAJnrk1Y_RLezfBq7sfgErGq3uT1t3czA+EWHg44zEXp9VrYF=Q@mail.gmail.com> <9bfa2c7a-1b17-41c5-9846-340e6a5b4b66@linux.alibaba.com>
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On Fri, Jun 26, 2026 at 10:22:17AM +0800, Gao Xiang wrote:
> It's just my rough thought, as I said in the previous year, I
> still don't have a strong tendency but it's my suggestion over
> these years.
>
> Anyway since you're actively working/changing on iomap, so
> it's fine to just respect your ideas/efforts if you don't
> think it's worth, but as a record of my thoughts here again.

This does sound like a lot of work, and I'm not a 100% sold on
the benefits, although getting rid of callbacks would be nice.

I'd be tempted to say that as a first step we should move the the
single callback, as a second stop (after converting everyone to
the single callback) to inline for performance critical path, and
then see if we can massage it into a pure iterator without much
downside instead of trying to do everything at once.

As you seem to have the strongest opinion here, I'd love to see
a proof of concept from you to get everyone excited.