From: Christoph Hellwig <hch@infradead.org>
To: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Oliver Mangold <oliver.mangold@pm.me>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: set bi_vcnt when cloning bio
Date: Wed, 19 Feb 2025 22:11:36 -0800 [thread overview]
Message-ID: <Z7bHmJHI1ewrFZsa@infradead.org> (raw)
In-Reply-To: <20250215-clone-bi_vcnt-v1-1-5d00c95fd53a@kernel.org>
On Sat, Feb 15, 2025 at 11:58:15AM +0100, Andreas Hindborg wrote:
> When cloning a bio, the `bio.bi_vcnt` field is not cloned. This is a
> problem if users want to perform bounds checks on the `bio.bi_io_vec`
> field.
Right now bi_vcnt is supposed to be an implementation detail for
bio_add_*, which obviously can't be called on cloned bio. Except for the
usual abuse in bcache/bcachefs that has mostly kept up except for a few
read-only checks in the completion routines which also can't be called
on cloned bios.
It would be nice to use it as a __counted_by bound for bi_io_vec, but
until that is supported on pointers in addition to the flexible arrays
we can't actually do that. So as-is I don't really see a point in
just assigning the value if we don't actually use it.
prev parent reply other threads:[~2025-02-20 6:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-15 10:58 [PATCH] block: set bi_vcnt when cloning bio Andreas Hindborg
2025-02-18 10:40 ` John Garry
2025-02-18 11:40 ` Andreas Hindborg
2025-02-18 17:12 ` John Garry
2025-02-18 18:20 ` Andreas Hindborg
2025-02-18 22:21 ` Bart Van Assche
2025-02-19 14:19 ` John Garry
2025-02-20 6:11 ` Christoph Hellwig [this message]
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