linux-kernel - Re: [PATCH v4 5/7] rust: io: add `register!` macro

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <DG1DP20EZCTK.2YW5G4C198BQT@kernel.org>
Date: Thu, 29 Jan 2026 22:08:02 +0100
From: "Danilo Krummrich" <dakr@...nel.org>
To: "Gary Guo" <gary@...yguo.net>
Cc: "Alexandre Courbot" <acourbot@...dia.com>, "Alice Ryhl"
 <aliceryhl@...gle.com>, "Daniel Almeida" <daniel.almeida@...labora.com>,
 "Miguel Ojeda" <ojeda@...nel.org>, "Boqun Feng" <boqun.feng@...il.com>,
 Björn Roy Baron <bjorn3_gh@...tonmail.com>, "Benno Lossin"
 <lossin@...nel.org>, "Andreas Hindborg" <a.hindborg@...nel.org>, "Trevor
 Gross" <tmgross@...ch.edu>, "Yury Norov" <yury.norov@...il.com>, "John
 Hubbard" <jhubbard@...dia.com>, "Alistair Popple" <apopple@...dia.com>,
 "Joel Fernandes" <joelagnelf@...dia.com>, "Timur Tabi" <ttabi@...dia.com>,
 "Edwin Peer" <epeer@...dia.com>, "Eliot Courtney" <ecourtney@...dia.com>,
 "Dirk Behme" <dirk.behme@...bosch.com>, "Steven Price"
 <steven.price@....com>, <rust-for-linux@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 5/7] rust: io: add `register!` macro

On Thu Jan 29, 2026 at 3:10 PM CET, Gary Guo wrote:
> The issue with `Deref` bound here is that now you *require* a level of
> indirection. If something implements `Io` directly, you cannot use it with the
> method. While `&Bar` is accepted, `&Mmio` is not because `Mmio` is a direct
> implementor of `Io` and not deref to it.
>
> A `Deref` bound also does not help if, say, a type is `Arc<Bar>` which needs two
> level of dereffing before it is Io. For consistency I think it's best to avoid
> `Deref` call all together

I agree with that and we will probably run into this once we start implementing
the I/O traits for things like DMA memory.

We could use AsRef or a custom trait instead, but I'd rather leave this for a
subsequent series, as it requires more changes. They should also be transparent
to users.