[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20241030-borrow-mut-v1-1-8f0ceaf78eaf@gmail.com>
Date: Wed, 30 Oct 2024 16:46:38 -0400
From: Tamir Duberstein <tamird@...il.com>
To: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>,
Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
Björn Roy Baron <bjorn3_gh@...tonmail.com>,
Benno Lossin <benno.lossin@...ton.me>,
Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>,
Trevor Gross <tmgross@...ch.edu>, Danilo Krummrich <dakr@...nel.org>
Cc: rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
Tamir Duberstein <tamird@...il.com>
Subject: [PATCH 1/5] rust: arc: use `NonNull::new_unchecked`
There is no need to check (and panic on violations of) the safety
requirements on `ForeignOwnable` functions. Avoiding the check is
consistent with the implementation of `ForeignOwnable` for `Box`.
Signed-off-by: Tamir Duberstein <tamird@...il.com>
---
rust/kernel/sync/arc.rs | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index db9da352d588f65348aa7a5204abbb165b70197f..4857230bd8d410bcca97b2081c3ce2f617ee7921 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -337,9 +337,9 @@ fn into_foreign(self) -> *const core::ffi::c_void {
}
unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> ArcBorrow<'a, T> {
- // By the safety requirement of this function, we know that `ptr` came from
- // a previous call to `Arc::into_foreign`.
- let inner = NonNull::new(ptr as *mut ArcInner<T>).unwrap();
+ // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
+ // call to `Self::into_foreign`.
+ let inner = unsafe { NonNull::new_unchecked(ptr as _) };
// SAFETY: The safety requirements of `from_foreign` ensure that the object remains alive
// for the lifetime of the returned value.
@@ -347,10 +347,14 @@ unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> ArcBorrow<'a, T> {
}
unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {
+ // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
+ // call to `Self::into_foreign`.
+ let inner = unsafe { NonNull::new_unchecked(ptr as _) };
+
// SAFETY: By the safety requirement of this function, we know that `ptr` came from
// a previous call to `Arc::into_foreign`, which guarantees that `ptr` is valid and
// holds a reference count increment that is transferrable to us.
- unsafe { Self::from_inner(NonNull::new(ptr as _).unwrap()) }
+ unsafe { Self::from_inner(inner) }
}
}
--
2.47.0
Powered by blists - more mailing lists