Received-SPF: pass (google.com: domain of linux-kernel+bounces-45245-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Precedence: bulk
MIME-Version: 1.0
References: <20240130-rust-bit-v1-1-ed2ed6389a58@christina-quast.de>
In-Reply-To: <20240130-rust-bit-v1-1-ed2ed6389a58@christina-quast.de>
From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date: Tue, 30 Jan 2024 21:10:54 +0100
Message-ID: <CANiq72n5nuyA7nuX1NreS4JXPcyqN2iT=8-MnGBcT=a1Hufqbw@mail.gmail.com>
Subject: Re: [PATCH] rust: prelude: add bit function
To: Christina Quast <contact@christina-quast.de>
Cc: Miguel Ojeda <ojeda@kernel.org>, Alex Gaynor <alex.gaynor@gmail.com>, 
	Wedson Almeida Filho <wedsonaf@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>, 
	Benno Lossin <benno.lossin@proton.me>, Andreas Hindborg <a.hindborg@samsung.com>, 
	Alice Ryhl <aliceryhl@google.com>, rust-for-linux@vger.kernel.org, 
	linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Hi Christina,

Thanks for the patch! Please see below.

On Tue, Jan 30, 2024 at 8:48=E2=80=AFPM Christina Quast
<contact@christina-quast.de> wrote:
>
> In order to create masks easily, the define BIT() is used in C code.
> This commit adds the same functionality to the rust kernel.
>
> To use it, include the following into your rust file:
> use kernel::prelude::bit

This is the prelude, i.e. the point is that it does not need to be `use`d.

Did you check the `rust` branch? We had something like this there.

> diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
> index ae21600970b3..16e483de2f27 100644
> --- a/rust/kernel/prelude.rs
> +++ b/rust/kernel/prelude.rs

Please note that the prelude is meant to re-export existing
functionality elsewhere in the `kernel` crate, not to define items
there.

> +/// # Arguments
> +///
> +/// * `n` - A `u32` that specifies the bit position (zero-based index)

We don't use "Arguments"-like sections. Please see other functions'
documentation to see how we usually do it.

> +/// # Example

Please use the plural.

> +/// ```
> +/// let b =3D bit(2);
> +/// assert_eq!(b, 4);

The example is not closed.

> +#[inline]
> +pub const fn bit(n: u32) -> u32 {
> +    1 << n
> +}

Should it be a generic?

Cheers,
Miguel