Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20221206010519.39075-1-ojeda@kernel.org>
In-Reply-To: <20221206010519.39075-1-ojeda@kernel.org>
From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Tue, 17 Jan 2023 00:32:00 +0100
Message-ID: <CANiq72kTrfYzmgdLjOecsVTQzHdy_ZDaCO2KgbODtHpL0pS7Qw@mail.gmail.com>
Subject: Re: [PATCH v1] rust: alloc: remove the `borrow` module (`ToOwned`, `Cow`)
To:     ojeda@kernel.org
Cc:     Wedson Almeida Filho <wedsonaf@gmail.com>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        patches@lists.linux.dev, Josh Triplett <josh@joshtriplett.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Dec 6, 2022 at 2:05 AM <ojeda@kernel.org> wrote:
>
> From: Miguel Ojeda <ojeda@kernel.org>
>
> The `Cow` type [1] requires that its generic parameter type implements
> the `ToOwned` trait [2], which provides a method to create owned data
> from borrowed data, usually by cloning.
>
> However, it is infallible, and thus in most cases it is not useful for
> the kernel. [3]
>
> Therefore, introduce `cfg(no_borrow)` to remove the `borrow` module
> (which contains `ToOwned` and `Cow`) from `alloc`.
>
> Link: https://doc.rust-lang.org/alloc/borrow/enum.Cow.html [1]
> Link: https://doc.rust-lang.org/alloc/borrow/trait.ToOwned.html [2]
> Link: https://lore.kernel.org/rust-for-linux/20221204103153.117675b1@GaryWorkstation/ [3]
> Cc: Gary Guo <gary@garyguo.net>
> Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Applied to rust-next, thanks all!

Cheers,
Miguel