Commit e93a2386 authored by Benno Lossin's avatar Benno Lossin
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rust: pin-init: implement `ZeroableOption` for `&T` and `&mut T` 

`Option<&T>` and `Option<&mut T>` are documented [1] to have the `None`
variant be all zeroes.

Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1]
Link: https://github.com/Rust-for-Linux/pin-init/pull/56/commits/5ef1638c79e019d3dc0c62db5905601644c2e60a
Link: https://lore.kernel.org/all/20250523145125.523275-5-lossin@kernel.org


Signed-off-by: default avatarBenno Lossin <lossin@kernel.org>
parent d67b3701

rust/pin-init/src/lib.rs

+7 −0
Original line number Diff line number Diff line
@@ -1546,6 +1546,13 @@ pub unsafe trait ZeroableOption {} 
// SAFETY: by the safety requirement of `ZeroableOption`, this is valid.

unsafe impl<T: ZeroableOption> Zeroable for Option<T> {}



// SAFETY: `Option<&T>` is part of the option layout optimization guarantee:

// <https://doc.rust-lang.org/stable/std/option/index.html#representation>.

unsafe impl<T> ZeroableOption for &T {}

// SAFETY: `Option<&mut T>` is part of the option layout optimization guarantee:

// <https://doc.rust-lang.org/stable/std/option/index.html#representation>.

unsafe impl<T> ZeroableOption for &mut T {}



/// Create an initializer for a zeroed `T`.

///

/// The returned initializer will write `0x00` to every byte of the given `slot`.