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authorBenno Lossin <benno.lossin@proton.me>2023-08-14 08:47:40 +0000
committerMiguel Ojeda <ojeda@kernel.org>2023-08-21 14:31:49 +0200
commit1a8076ac6d83825bedb2050e67db0f2635acbb09 (patch)
tree63bf052855987033b3f1e72920f2a1a6cea31105 /rust
parent2e704f1883f5dd2f1380944c7d969c817fcd189e (diff)
downloadlwn-1a8076ac6d83825bedb2050e67db0f2635acbb09.tar.gz
lwn-1a8076ac6d83825bedb2050e67db0f2635acbb09.zip
rust: init: make `PinInit<T, E>` a supertrait of `Init<T, E>`
Remove the blanket implementation of `PinInit<T, E> for I where I: Init<T, E>`. This blanket implementation prevented custom types that implement `PinInit`. Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230814084602.25699-12-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust')
-rw-r--r--rust/kernel/init.rs21
-rw-r--r--rust/kernel/init/__internal.rs12
2 files changed, 20 insertions, 13 deletions
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs
index 0e44b3cc2eed..0f9c8576697e 100644
--- a/rust/kernel/init.rs
+++ b/rust/kernel/init.rs
@@ -799,7 +799,7 @@ pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized {
///
/// [`Arc<T>`]: crate::sync::Arc
#[must_use = "An initializer must be used in order to create its value."]
-pub unsafe trait Init<T: ?Sized, E = Infallible>: Sized {
+pub unsafe trait Init<T: ?Sized, E = Infallible>: PinInit<T, E> {
/// Initializes `slot`.
///
/// # Safety
@@ -810,18 +810,6 @@ pub unsafe trait Init<T: ?Sized, E = Infallible>: Sized {
unsafe fn __init(self, slot: *mut T) -> Result<(), E>;
}
-// SAFETY: Every in-place initializer can also be used as a pin-initializer.
-unsafe impl<T: ?Sized, E, I> PinInit<T, E> for I
-where
- I: Init<T, E>,
-{
- unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
- // SAFETY: `__init` meets the same requirements as `__pinned_init`, except that it does not
- // require `slot` to not move after init.
- unsafe { self.__init(slot) }
- }
-}
-
/// Creates a new [`PinInit<T, E>`] from the given closure.
///
/// # Safety
@@ -964,6 +952,13 @@ unsafe impl<T, E> Init<T, E> for T {
}
}
+// SAFETY: Every type can be initialized by-value. `__pinned_init` calls `__init`.
+unsafe impl<T, E> PinInit<T, E> for T {
+ unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
+ unsafe { self.__init(slot) }
+ }
+}
+
/// Smart pointer that can initialize memory in-place.
pub trait InPlaceInit<T>: Sized {
/// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this
diff --git a/rust/kernel/init/__internal.rs b/rust/kernel/init/__internal.rs
index 7abd1fb65e41..12e195061525 100644
--- a/rust/kernel/init/__internal.rs
+++ b/rust/kernel/init/__internal.rs
@@ -32,6 +32,18 @@ where
}
}
+// SAFETY: While constructing the `InitClosure`, the user promised that it upholds the
+// `__pinned_init` invariants.
+unsafe impl<T: ?Sized, F, E> PinInit<T, E> for InitClosure<F, T, E>
+where
+ F: FnOnce(*mut T) -> Result<(), E>,
+{
+ #[inline]
+ unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
+ (self.0)(slot)
+ }
+}
+
/// This trait is only implemented via the `#[pin_data]` proc-macro. It is used to facilitate
/// the pin projections within the initializers.
///