From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Joanne Koong <joannelkoong@gmail.com>,
brauner@kernel.org, miklos@szeredi.hu, hch@infradead.org,
linux-fsdevel@vger.kernel.org, kernel-team@meta.com,
linux-xfs@vger.kernel.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH v1 04/16] iomap: use iomap_iter->private for stashing read/readahead bio
Date: Wed, 3 Sep 2025 23:07:13 -0700 [thread overview]
Message-ID: <aLkskcgl3Z91oIVB@infradead.org> (raw)
In-Reply-To: <20250903203031.GM1587915@frogsfrogsfrogs>
On Wed, Sep 03, 2025 at 01:30:31PM -0700, Darrick J. Wong wrote:
> On Fri, Aug 29, 2025 at 04:56:15PM -0700, Joanne Koong wrote:
> > Use the iomap_iter->private field for stashing any read/readahead bios
> > instead of defining the bio as part of the iomap_readpage_ctx struct.
> > This makes the read/readahead interface more generic. Some filesystems
> > that will be using iomap for read/readahead may not have CONFIG_BLOCK
> > set.
>
> Sorry, but I don't like abusing iomap_iter::private because (a) it's a
> void pointer which means shenanigans; and (b) private exists to store
> some private data for an iomap caller, not iomap itself.
I don't think we can do without the void pointer for a generic
lower library, but I fully agree on not using iomap_iter::private.
We'll need that for something caller provided sooner or later.
The right way ahead is to have a void pointer for the I/O-type specific
context in iomap_readpage_ctx, and then hopefully reasonable type safe
wrappers around it.
next prev parent reply other threads:[~2025-09-04 6:07 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-29 23:56 [PATCH v1 00/16] fuse: use iomap for buffered reads + readahead Joanne Koong
2025-08-29 23:56 ` [PATCH v1 01/16] iomap: move async bio read logic into helper function Joanne Koong
2025-09-03 20:16 ` Darrick J. Wong
2025-09-04 6:00 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 02/16] iomap: rename cur_folio_in_bio to folio_unlocked Joanne Koong
2025-09-03 20:26 ` [PATCH v1 02/16] iomap: rename cur_folio_in_bio to folio_unlockedOM Darrick J. Wong
2025-09-04 6:03 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 03/16] iomap: refactor read/readahead completion Joanne Koong
2025-09-04 6:05 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 04/16] iomap: use iomap_iter->private for stashing read/readahead bio Joanne Koong
2025-09-03 20:30 ` Darrick J. Wong
2025-09-04 6:07 ` Christoph Hellwig [this message]
2025-08-29 23:56 ` [PATCH v1 05/16] iomap: propagate iomap_read_folio() error to caller Joanne Koong
2025-09-03 20:32 ` Darrick J. Wong
2025-09-04 6:09 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 06/16] iomap: move read/readahead logic out of CONFIG_BLOCK guard Joanne Koong
2025-08-29 23:56 ` [PATCH v1 07/16] iomap: iterate through entire folio in iomap_readpage_iter() Joanne Koong
2025-09-03 20:43 ` Darrick J. Wong
2025-09-04 6:14 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 08/16] iomap: rename iomap_readpage_iter() to iomap_readfolio_iter() Joanne Koong
2025-09-04 6:15 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 09/16] iomap: rename iomap_readpage_ctx struct to iomap_readfolio_ctx Joanne Koong
2025-09-03 20:44 ` Darrick J. Wong
2025-08-29 23:56 ` [PATCH v1 10/16] iomap: add iomap_start_folio_read() helper Joanne Koong
2025-09-03 20:52 ` Darrick J. Wong
2025-08-29 23:56 ` [PATCH v1 11/16] iomap: make start folio read and finish folio read public APIs Joanne Koong
2025-09-03 20:53 ` Darrick J. Wong
2025-09-04 6:15 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 12/16] iomap: add iomap_read_ops for read and readahead Joanne Koong
2025-09-03 21:08 ` Darrick J. Wong
2025-09-04 6:21 ` Christoph Hellwig
2025-08-29 23:56 ` [PATCH v1 13/16] iomap: add a private arg " Joanne Koong
2025-08-30 1:54 ` Gao Xiang
2025-09-02 21:24 ` Joanne Koong
2025-09-03 1:55 ` Gao Xiang
2025-09-03 21:11 ` Darrick J. Wong
2025-08-29 23:56 ` [PATCH v1 14/16] fuse: use iomap for read_folio Joanne Koong
2025-09-03 21:13 ` Darrick J. Wong
2025-08-29 23:56 ` [PATCH v1 15/16] fuse: use iomap for readahead Joanne Koong
2025-09-03 21:17 ` Darrick J. Wong
2025-08-29 23:56 ` [PATCH v1 16/16] fuse: remove fuse_readpages_end() null mapping check Joanne Koong
2025-09-02 9:21 ` Miklos Szeredi
2025-09-02 21:19 ` Joanne Koong
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