Date:   Thu, 2 Feb 2023 14:28:04 +0000
From:   Gary Guo <gary@garyguo.net>
To:     Boqun Feng <boqun.feng@gmail.com>
Cc:     rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        Will Deacon <will@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        =?UTF-8?B?QmrDtnJu?= Roy Baron <bjorn3_gh@protonmail.com>,
        Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Subject: Re: [RFC 4/5] rust: sync: impl Debug for {Unique,}Arc
Message-ID: <20230202142804.753c898c.gary@garyguo.net>
In-Reply-To: <20230201232244.212908-5-boqun.feng@gmail.com>
References: <20230201232244.212908-1-boqun.feng@gmail.com>
        <20230201232244.212908-5-boqun.feng@gmail.com>
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On Wed,  1 Feb 2023 15:22:43 -0800
Boqun Feng <boqun.feng@gmail.com> wrote:

> This allows printing macros to print the data and the refcount nubmer
> of these struct for debugging purposes.
> 
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> ---
>  rust/kernel/sync/arc.rs | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
> index 4d8de20c996f..f143d8305c36 100644
> --- a/rust/kernel/sync/arc.rs
> +++ b/rust/kernel/sync/arc.rs
> @@ -474,6 +474,7 @@ impl<T: ?Sized> Deref for ArcBorrow<'_, T> {
>  ///
>  /// # test().unwrap();
>  /// ```
> +#[derive(Debug)]

I don't think this should be a `#[derive(Debug)]`. For `UniqueArc` the
refcount field in `Arc` is useless, and we should just delegate the
`Debug` impl to that of deref, just like `Display` does.

Best,
Gary