From: Christoph Hellwig <hch@infradead.org>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
Keith Busch <kbusch@meta.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, snitzer@kernel.org,
axboe@kernel.dk, dw@davidwei.uk, brauner@kernel.org,
Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCHv2 1/7] block: check for valid bio while splitting
Date: Sun, 10 Aug 2025 10:14:44 -0700 [thread overview]
Message-ID: <aJjThNwGsrjFtWlg@infradead.org> (raw)
In-Reply-To: <aJi9RgOAjXm8Hwlo@kbusch-mbp>
On Sun, Aug 10, 2025 at 09:39:50AM -0600, Keith Busch wrote:
> > > bytes = ALIGN_DOWN(bytes, bio_split_alignment(bio, lim));
> > > + if (!bytes)
> > > + return -EINVAL;
> >
> > How is this related to the other hunk and the patch description?
>
> The patchset allows you to submit an io with vectors that are partial
> logical blocks. Misuse could create a bio that exceeds the device max
> vectors or introduces virtual boundary gaps, requiring a split into
> something that is smaller than a block size. This check catches that.
>
> Quick example: nvme with a 4k logical block size, and the usual 4k
> virtual boundary. Send an io with four vectors iov_len=1k. The total
> size is block sized, but there's no way that could split into a valid
> io. There's a test specifically for this in my reply about xfstests.
Can you turn the above into a comment explaining the check?
next prev parent reply other threads:[~2025-08-10 17:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-05 14:11 [PATCHv2 0/7] direct-io: even more flexible io vectors Keith Busch
2025-08-05 14:11 ` [PATCHv2 1/7] block: check for valid bio while splitting Keith Busch
2025-08-10 14:37 ` Christoph Hellwig
2025-08-10 15:39 ` Keith Busch
2025-08-10 17:14 ` Christoph Hellwig [this message]
2025-08-13 20:06 ` Keith Busch
2025-08-13 20:41 ` Bart Van Assche
2025-08-13 21:01 ` Keith Busch
2025-08-13 23:17 ` Bart Van Assche
2025-08-14 1:42 ` Damien Le Moal
2025-08-13 21:23 ` Martin K. Petersen
2025-08-13 21:52 ` Keith Busch
2025-08-18 4:49 ` Christoph Hellwig
2025-08-05 14:11 ` [PATCHv2 2/7] block: align the bio after building it Keith Busch
2025-08-06 6:07 ` Hannes Reinecke
2025-08-10 14:43 ` Christoph Hellwig
2025-08-05 14:11 ` [PATCHv2 3/7] block: simplify direct io validity check Keith Busch
2025-08-05 14:11 ` [PATCHv2 4/7] iomap: " Keith Busch
2025-08-06 6:07 ` Hannes Reinecke
2025-08-05 14:11 ` [PATCHv2 5/7] block: remove bdev_iter_is_aligned Keith Busch
2025-08-05 14:11 ` [PATCHv2 6/7] blk-integrity: use simpler alignment check Keith Busch
2025-08-05 14:11 ` [PATCHv2 7/7] iov_iter: remove iov_iter_is_aligned Keith Busch
2025-08-06 6:08 ` Hannes Reinecke
2025-08-06 3:03 ` [PATCHv2 0/7] direct-io: even more flexible io vectors Martin K. Petersen
2025-08-06 14:51 ` Christoph Hellwig
2025-08-07 23:20 ` Keith Busch
2025-08-11 10:32 ` Christoph Hellwig
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