Re: [RFC PATCH v1 0/3] iomap: convert to in-iter ->iomap_next() model

[Christoph Hellwig <hch@lst.de>]

On Fri, Jun 26, 2026 at 01:35:33PM +0800, Gao Xiang wrote:
> I know it's much better to "show the code" but I also think it's
> useful to comment ideas now rather than later in case that anyone
> is interested so that it could be useful for their adaption.

Sure.

> I hope I could arrange it in my formal todo list, but I've already
> had a bunch of other things (erofs fsdax dedupe support as I told
> to you since it impacts workloads, and some overlayfs improvement
> and more) in my scheduling list.
>
> Although I tend to play with this idea, it's not a blocker on
> my main interested use cases for now.  Also see if some
> complicated conversion like btrfs and f2fs can make more related
> developers interested in following this way.

Yeah.  But for now I'd like to get the relatively low hanging fruit
done.  And Joanne showed that moving from begin/end to an iter is
actually way simpler than I thought by having the iomap_process
helper that still does get callbacks, but which get inlined.  So
I'd be really happy to get this done ASAP before we get a lot more
conversions, and also to avoid having a partial transitition where
we need to keep the old ops around for too long.

After that doing the inlining as in patch 3 becomes pretty easy,
so we can do it where it matter like direct I/O.  And also once
we are down to a single callback I think we have a better baseline
for your idea.

>
> Thanks,
> Gao Xiang
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