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| author | Benno Lossin <benno.lossin@proton.me> | 2023-08-14 08:47:32 +0000 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2023-08-21 14:31:49 +0200 |
| commit | 2e704f1883f5dd2f1380944c7d969c817fcd189e (patch) | |
| tree | a1fdc5b19b6b24890542983a3033093f8a450a84 | |
| parent | 674b1c7aed6082e1ce329bb3bcb49e7eb9913e79 (diff) | |
| download | lwn-2e704f1883f5dd2f1380944c7d969c817fcd189e.tar.gz lwn-2e704f1883f5dd2f1380944c7d969c817fcd189e.zip | |
rust: init: implement `Zeroable` for `UnsafeCell<T>` and `Opaque<T>`
`UnsafeCell<T>` and `T` have the same layout so if `T` is `Zeroable`
then so should `UnsafeCell<T>` be. This allows using the derive macro
for `Zeroable` on types that contain an `UnsafeCell<T>`.
Since `Opaque<T>` contains a `MaybeUninit<T>`, all bytes zero is a valid
bit pattern for that type.
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230814084602.25699-11-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
| -rw-r--r-- | rust/kernel/init.rs | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index 429b485d8825..0e44b3cc2eed 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -202,11 +202,12 @@ use crate::{ error::{self, Error}, sync::UniqueArc, - types::ScopeGuard, + types::{Opaque, ScopeGuard}, }; use alloc::boxed::Box; use core::{ alloc::AllocError, + cell::UnsafeCell, convert::Infallible, marker::PhantomData, mem::MaybeUninit, @@ -1151,6 +1152,11 @@ impl_zeroable! { // SAFETY: Type is allowed to take any value, including all zeros. {<T>} MaybeUninit<T>, + // SAFETY: Type is allowed to take any value, including all zeros. + {<T>} Opaque<T>, + + // SAFETY: `T: Zeroable` and `UnsafeCell` is `repr(transparent)`. + {<T: ?Sized + Zeroable>} UnsafeCell<T>, // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). Option<NonZeroU8>, Option<NonZeroU16>, Option<NonZeroU32>, Option<NonZeroU64>, |