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author | Benno Lossin <benno.lossin@proton.me> | 2023-08-14 08:47:40 +0000 |
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committer | Miguel Ojeda <ojeda@kernel.org> | 2023-08-21 14:31:49 +0200 |
commit | 1a8076ac6d83825bedb2050e67db0f2635acbb09 (patch) | |
tree | 63bf052855987033b3f1e72920f2a1a6cea31105 /rust | |
parent | 2e704f1883f5dd2f1380944c7d969c817fcd189e (diff) | |
download | lwn-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.rs | 21 | ||||
-rw-r--r-- | rust/kernel/init/__internal.rs | 12 |
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. /// |