From bd780aea671eda9660837c05d9ba58de22ceecad Mon Sep 17 00:00:00 2001
From: Alice Ryhl <aliceryhl@google.com>
Date: Wed, 17 May 2023 20:08:13 +0000
Subject: [PATCH] rust: sync: add `Arc::ptr_eq`
Add a method for comparing whether two `Arc` pointers reference the same
underlying object.
This comparison can already be done by getting a reference to the inner
values and comparing whether the references have the same address.
However, writing `Arc::ptr_eq(a, b)` is generally less error-prone than
doing the same check on the references, since you might otherwise
accidentally compare the two `&Arc<T>` references instead, which wont
work because those are pointers to pointers to the inner value, when you
just want to compare the pointers to the inner value.
Also, this method might optimize better because getting a reference to
the inner value involves offsetting the pointer, which this method does
not need to do.
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: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230517200814.3157916-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
rust/kernel/sync/arc.rs | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index 1b0734fdf6a7..b03d84f7ce87 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -221,6 +221,11 @@ impl<T: ?Sized> Arc<T> {
// reference can be created.
unsafe { ArcBorrow::new(self.ptr) }
}
+
+ /// Compare whether two [`Arc`] pointers reference the same underlying object.
+ pub fn ptr_eq(this: &Self, other: &Self) -> bool {
+ core::ptr::eq(this.ptr.as_ptr(), other.ptr.as_ptr())
+ }
}
impl<T: 'static> ForeignOwnable for Arc<T> {