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;
Date:   Fri, 14 Jul 2023 09:44:07 +0000
In-Reply-To: <20230714-zeroed-v1-1-494d6820d61b@asahilina.net>
Mime-Version: 1.0
References: <20230714-zeroed-v1-1-494d6820d61b@asahilina.net>
Message-ID: <20230714094407.2188895-1-aliceryhl@google.com>
Subject: Re: [PATCH] rust: init: Implement Zeroable::zeroed()
From:   Alice Ryhl <aliceryhl@google.com>
To:     lina@asahilina.net
Cc:     alex.gaynor@gmail.com, benno.lossin@proton.me,
        bjorn3_gh@protonmail.com, boqun.feng@gmail.com, gary@garyguo.net,
        linux-kernel@vger.kernel.org, ojeda@kernel.org,
        rust-for-linux@vger.kernel.org, wedsonaf@gmail.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Asahi Lina <lina@asahilina.net> writes:
> +pub unsafe trait Zeroable: core::marker::Sized {
> +    /// Create a new zeroed T.
> +    ///
> +    /// Directly returns a zeroed T, analogous to Default::default().
> +    fn zeroed() -> Self {
> +        unsafe { core::mem::zeroed() }
> +    }
> +}

I don't think this trait needs to require `Sized`. How about the
following alternate implementation?

pub unsafe trait Zeroable {
    /// Create a new zeroed T.
    ///
    /// Directly returns a zeroed T, analogous to Default::default().
    fn zeroed() -> Self
    where
        Self: core::marker::Sized,
    {
        unsafe { core::mem::zeroed() }
    }
}

Then types like [T] can also implement Zeroable when T does.

If you make the above change, then you may add my
  Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Alice