From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Keith Busch <kbusch@meta.com>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
hch@lst.de, axboe@kernel.dk
Subject: Re: [PATCH 1/2] block: accumulate segment page gaps per bio
Date: Wed, 6 Aug 2025 16:53:34 +0200 [thread overview]
Message-ID: <20250806145333.GA20102@lst.de> (raw)
In-Reply-To: <aJKLGy9UkVjJTIIQ@kbusch-mbp>
On Tue, Aug 05, 2025 at 04:52:11PM -0600, Keith Busch wrote:
> On Tue, Aug 05, 2025 at 12:56:07PM -0700, Keith Busch wrote:
> > + bv = next->bio->bi_io_vec[0];
> > + bvprv = req->biotail->bi_io_vec[req->biotail->bi_vcnt - 1];
>
> Hm, commit 7bcd79ac50d9d8 suggests I missed something obvious about not
> being allowed to use 'bi_vcnt - 1' for the tail bvec of the previous
> bio. I guess it's some stacking thing.
It is bio cloning and splitting. bi_io_vec is the original payload added
to a bio, and directly accessing it is only allowed for the submitter,
i.e. usually the file system. The I/O stack always need to go through
the bio_iter to deal with split/cloned/truncated/partially completed and
resubmitted bios.
next prev parent reply other threads:[~2025-08-06 14:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-05 19:56 [PATCH 1/2] block: accumulate segment page gaps per bio Keith Busch
2025-08-05 19:56 ` [PATCH 2/2] nvme: remove virtual boundary for sgl capable devices Keith Busch
2025-08-06 14:55 ` Christoph Hellwig
2025-08-06 15:04 ` Keith Busch
2025-08-05 20:32 ` [PATCH 1/2] block: accumulate segment page gaps per bio Caleb Sander Mateos
2025-08-05 20:52 ` Keith Busch
2025-08-05 22:52 ` Keith Busch
2025-08-06 14:53 ` Christoph Hellwig [this message]
2025-08-06 15:17 ` Keith Busch
2025-08-06 14:56 ` Christoph Hellwig
2025-08-06 15:44 ` Keith Busch
2025-08-10 14:31 ` Christoph Hellwig
2025-08-11 15:27 ` Keith Busch
2025-08-11 16:17 ` Christoph Hellwig
2025-08-20 19:22 ` Keith Busch
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