Feedback-ID: iad51458e:Fastmail
From:   Boqun Feng <boqun.feng@gmail.com>
To:     rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     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>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= <bjorn3_gh@protonmail.com>,
        Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Subject: [RFC 1/5] rust: sync: impl Display for {Unique,}Arc
Date:   Wed,  1 Feb 2023 15:22:40 -0800
Message-Id: <20230201232244.212908-2-boqun.feng@gmail.com>
In-Reply-To: <20230201232244.212908-1-boqun.feng@gmail.com>
References: <20230201232244.212908-1-boqun.feng@gmail.com>
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This allows printing the inner data of `Arc` and its friends if the
inner data implements `Display`. It's useful for logging and debugging
purpose.

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 519a6ec43644..fc680a4a795c 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -22,6 +22,7 @@ use crate::{
 };
 use alloc::boxed::Box;
 use core::{
+    fmt,
     marker::{PhantomData, Unsize},
     mem::{ManuallyDrop, MaybeUninit},
     ops::{Deref, DerefMut},
@@ -522,3 +523,15 @@ impl<T: ?Sized> DerefMut for UniqueArc<T> {
         unsafe { &mut self.inner.ptr.as_mut().data }
     }
 }
+
+impl<T: fmt::Display + ?Sized> fmt::Display for UniqueArc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self.deref(), f)
+    }
+}
+
+impl<T: fmt::Display + ?Sized> fmt::Display for Arc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self.deref(), f)
+    }
+}
-- 
2.39.1