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From:   Andreas Hindborg <nmi@metaspace.dk>
To:     y86-dev@protonmail.com
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>,
        Alice Ryhl <alice@ryhl.io>, rust-for-linux@vger.kernel.org,
        linux-kernel@vger.kernel.org, patches@lists.linux.dev,
        Andreas Hindborg <a.hindborg@samsung.com>
Subject: Re: [PATCH v3 03/13] rust: types: add `Opaque::raw_get`
Date:   Thu, 30 Mar 2023 14:32:19 +0200
In-reply-to: <20230329223239.138757-4-y86-dev@protonmail.com>
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y86-dev@protonmail.com writes:

> From: Benno Lossin <y86-dev@protonmail.com>
>
> This function mirrors `UnsafeCell::raw_get`. It avoids creating a
> reference and allows solely using raw pointers.
> The `pin-init` API will be using this, since uninitialized memory
> requires raw pointers.
>
> Signed-off-by: Benno Lossin <y86-dev@protonmail.com>
> ---

Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>

>  rust/kernel/types.rs | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
> index 9d0fdbc55843..ff2b2fac951d 100644
> --- a/rust/kernel/types.rs
> +++ b/rust/kernel/types.rs
> @@ -238,6 +238,14 @@ impl<T> Opaque<T> {
>      pub fn get(&self) -> *mut T {
>          UnsafeCell::raw_get(self.0.as_ptr())
>      }
> +
> +    /// Gets the value behind `this`.
> +    ///
> +    /// This function is useful to get access to the value without creating intermediate
> +    /// references.
> +    pub const fn raw_get(this: *const Self) -> *mut T {
> +        UnsafeCell::raw_get(this.cast::<UnsafeCell<T>>())
> +    }
>  }
>
>  /// A sum type that always holds either a value of type `L` or `R`.