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authorAlice Ryhl <aliceryhl@google.com>2023-06-14 14:53:28 +0300
committerMiguel Ojeda <ojeda@kernel.org>2023-08-10 02:18:34 +0300
commit35cad617df2eeef8440a38e82bb2d81ae32ca50d (patch)
treec242223c7b6afcd9846da86b59d6eeccfefbcda7 /rust/kernel
parent0bb1c9282e2cb38d199347d1d96b77f208b64810 (diff)
downloadlinux-35cad617df2eeef8440a38e82bb2d81ae32ca50d.tar.xz
rust: make `UnsafeCell` the outer type in `Opaque`
When combining `UnsafeCell` with `MaybeUninit`, it is idiomatic to use `UnsafeCell` as the outer type. Intuitively, this is because a `MaybeUninit<T>` might not contain a `T`, but we always want the effect of the `UnsafeCell`, even if the inner value is uninitialized. Now, strictly speaking, this doesn't really make a difference. The compiler will always apply the `UnsafeCell` effect even if the inner value is uninitialized. But I think we should follow the convention here. 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> Link: https://lore.kernel.org/r/20230614115328.2825961-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust/kernel')
-rw-r--r--rust/kernel/types.rs10
1 files changed, 5 insertions, 5 deletions
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index d479f8da8f38..c0b8bb1a7539 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -206,17 +206,17 @@ impl<T, F: FnOnce(T)> Drop for ScopeGuard<T, F> {
///
/// This is meant to be used with FFI objects that are never interpreted by Rust code.
#[repr(transparent)]
-pub struct Opaque<T>(MaybeUninit<UnsafeCell<T>>);
+pub struct Opaque<T>(UnsafeCell<MaybeUninit<T>>);
impl<T> Opaque<T> {
/// Creates a new opaque value.
pub const fn new(value: T) -> Self {
- Self(MaybeUninit::new(UnsafeCell::new(value)))
+ Self(UnsafeCell::new(MaybeUninit::new(value)))
}
/// Creates an uninitialised value.
pub const fn uninit() -> Self {
- Self(MaybeUninit::uninit())
+ Self(UnsafeCell::new(MaybeUninit::uninit()))
}
/// Creates a pin-initializer from the given initializer closure.
@@ -240,7 +240,7 @@ impl<T> Opaque<T> {
/// Returns a raw pointer to the opaque data.
pub fn get(&self) -> *mut T {
- UnsafeCell::raw_get(self.0.as_ptr())
+ UnsafeCell::get(&self.0).cast::<T>()
}
/// Gets the value behind `this`.
@@ -248,7 +248,7 @@ impl<T> Opaque<T> {
/// This function is useful to get access to the value without creating intermediate
/// references.
pub const fn raw_get(this: *const Self) -> *mut T {
- UnsafeCell::raw_get(this.cast::<UnsafeCell<T>>())
+ UnsafeCell::raw_get(this.cast::<UnsafeCell<MaybeUninit<T>>>()).cast::<T>()
}
}