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 <20230517200814.3157916-2-aliceryhl@google.com>
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From:   Andreas Hindborg <nmi@metaspace.dk>
To:     Alice Ryhl <aliceryhl@google.com>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        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>,
        Benno Lossin <benno.lossin@proton.me>,
        Will Deacon <will@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        patches@lists.linux.dev,
        Wedson Almeida Filho <walmeida@microsoft.com>
Subject: Re: [PATCH v1 2/2] rust: sync: implement `AsRef<T>` for `Arc<T>`
Date:   Tue, 23 May 2023 13:59:00 +0200
In-reply-to: <20230517200814.3157916-2-aliceryhl@google.com>
Message-ID: <877cszfeck.fsf@metaspace.dk>
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Alice Ryhl <aliceryhl@google.com> writes:

> This trait lets you use `Arc<T>` in code that is generic over smart
> pointer types.
>
> The `AsRef` trait should be implemented on all smart pointers. The
> standard library also implements it on the ordinary `Arc`.
>
> Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com>
> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

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

> ---
>  rust/kernel/sync/arc.rs | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
> index 274febe3bb06..9ec911e4a0c7 100644
> --- a/rust/kernel/sync/arc.rs
> +++ b/rust/kernel/sync/arc.rs
> @@ -264,6 +264,12 @@ impl<T: ?Sized> Deref for Arc<T> {
>      }
>  }
>  
> +impl<T: ?Sized> AsRef<T> for Arc<T> {
> +    fn as_ref(&self) -> &T {
> +        self.deref()
> +    }
> +}
> +
>  impl<T: ?Sized> Clone for Arc<T> {
>      fn clone(&self) -> Self {
>          // INVARIANT: C `refcount_inc` saturates the refcount, so it cannot overflow to zero.