Re: [RFC 4/5] rust: sync: impl Debug for {Unique,}Arc

From: Boqun Feng <boqun.feng@gmail.com>
To: Gary Guo <gary@garyguo.net>
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>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Vincenzo Palazzo" <vincenzopalazzodev@gmail.com>
Subject: Re: [RFC 4/5] rust: sync: impl Debug for {Unique,}Arc
Date: Fri, 3 Feb 2023 11:46:07 -0800	[thread overview]
Message-ID: <Y91kf/IMiYNw8BdR@boqun-archlinux> (raw)
In-Reply-To: <20230202142804.753c898c.gary@garyguo.net>

On Thu, Feb 02, 2023 at 02:28:04PM +0000, Gary Guo wrote:
> 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.
> 

I was just being lazy ;-) Will change this in v2.

Regards,
Boqun

> Best,
> Gary