From: "Alexandre Courbot" <acourbot@nvidia.com>
To: "Eliot Courtney" <ecourtney@nvidia.com>
Cc: "Alice Ryhl" <aliceryhl@google.com>,
"Burak Emir" <burak.emir@gmail.com>,
"Yury Norov" <yury.norov@gmail.com>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Boqun Feng" <boqun@kernel.org>, "Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Benno Lossin" <lossin@kernel.org>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>,
"Daniel Almeida" <daniel.almeida@collabora.com>,
"Tamir Duberstein" <tamird@kernel.org>,
"Onur Özkan" <work@onurozkan.dev>,
"David Airlie" <airlied@gmail.com>,
"Simona Vetter" <simona@ffwll.ch>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"John Hubbard" <jhubbard@nvidia.com>,
"Alistair Popple" <apopple@nvidia.com>,
"Timur Tabi" <ttabi@nvidia.com>, "Zhi Wang" <zhiw@nvidia.com>,
rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
nova-gpu@lists.linux.dev, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v7 06/10] rust: id_pool: take a NonZero capacity in with_capacity
Date: Fri, 21 Aug 2026 17:39:58 +0900 [thread overview]
Message-ID: <DKUHJF1YTTY6.1XXC1L2SYXEMF@nvidia.com> (raw)
In-Reply-To: <20260817-chid-v7-6-a5872e64d8f4@nvidia.com>
On Mon Aug 17, 2026 at 4:04 PM JST, Eliot Courtney wrote:
> There is no good reason to allocate an IdPool with zero capacity.
> Reflect this in IdPool::with_capacity.
>
> Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
I am not sure this one is justifiable; `KVec::with_capacity(0)` is
doable, so why not here? As long as it doesn't introduce soundness
issues I'd say this is the caller's business; a driver with a legitimate
empty IdPool use-case would now need to special-case it.
Now we do have an actual soundness issue with zero-sized IdPools, which
is that `find_unused_id` would panic with `CONFIG_RUST_BITMAP_HARDENED`,
but as I said on patch 5 I don't think it should anyway. Another
potential issue is that `grow_request` would not grow anything; but that
should be fixed there by handling the `capacity == 0` case. Actually
that would give justification for empty IdPools to exist: just like a
vector can start empty and grow, so can an IdPool.
next prev parent reply other threads:[~2026-08-21 8:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-17 7:04 [PATCH v7 00/10] rust: Add support for reserving of ranges of IDs Eliot Courtney
2026-08-17 7:04 ` [PATCH v7 01/10] rust: bitmap: use function-level cfg on kunit test Eliot Courtney
2026-08-17 10:29 ` Gary Guo
2026-08-17 19:42 ` Burak Emir
2026-08-17 7:04 ` [PATCH v7 02/10] rust: bitmap: restrict bitmap length to at most i32::MAX Eliot Courtney
2026-08-17 19:51 ` Burak Emir
2026-08-21 7:37 ` Alexandre Courbot
2026-08-17 7:04 ` [PATCH v7 03/10] rust: num: add nz! macro for compile time NonZero values Eliot Courtney
2026-08-19 20:07 ` Gary Guo
2026-08-21 7:39 ` Alexandre Courbot
2026-08-17 7:04 ` [PATCH v7 04/10] rust: sizes: implement SizeConstants for Alignment Eliot Courtney
2026-08-17 7:12 ` sashiko-bot
2026-08-21 7:46 ` Alexandre Courbot
2026-08-17 7:04 ` [PATCH v7 05/10] rust: bitmap: add contiguous area operations Eliot Courtney
2026-08-17 20:12 ` Burak Emir
2026-08-21 8:11 ` Alexandre Courbot
2026-08-21 8:31 ` Miguel Ojeda
2026-08-21 11:04 ` Alexandre Courbot
2026-08-17 7:04 ` [PATCH v7 06/10] rust: id_pool: take a NonZero capacity in with_capacity Eliot Courtney
2026-08-17 7:12 ` sashiko-bot
2026-08-17 20:13 ` Burak Emir
2026-08-21 8:39 ` Alexandre Courbot [this message]
2026-08-17 7:04 ` [PATCH v7 07/10] rust: id_pool: add contiguous ID reservation Eliot Courtney
2026-08-17 7:14 ` sashiko-bot
2026-08-17 20:21 ` Burak Emir
2026-08-21 8:30 ` Alexandre Courbot
2026-08-17 7:04 ` [PATCH v7 08/10] rust: id_pool: do not round capacity up to BitmapVec::MAX_INLINE_LEN Eliot Courtney
2026-08-17 20:39 ` Burak Emir
2026-08-17 7:04 ` [PATCH v7 09/10] gpu: nova-core: add ChannelIdPool Eliot Courtney
2026-08-17 7:04 ` [PATCH v7 10/10] rust: use Alignment size constants Eliot Courtney
2026-08-21 11:04 ` Alexandre Courbot
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