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| author |   Benno Lossin <lossin@kernel.org> | 2025-05-23 16:51:00 +0200 |
|---|---|---|
| committer | Benno Lossin <lossin@kernel.org> | 2025-06-11 21:13:56 +0200 |
| commit | e93a238605348bc40fed77ba5582e311376d113b (patch) | |
| tree | 08baf0c1e16fa34f184eb38135905e5d838b56ff | |
| parent | rust: pin-init: add `zeroed()` & `Zeroable::zeroed()` functions (diff) | |
| download | wireguard-linux-e93a238605348bc40fed77ba5582e311376d113b.tar.xz wireguard-linux-e93a238605348bc40fed77ba5582e311376d113b.zip | |
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: Benno Lossin <lossin@kernel.org>
| -rw-r--r-- | rust/pin-init/src/lib.rs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/rust/pin-init/src/lib.rs b/rust/pin-init/src/lib.rs index a5bb3939b58b..298a3e675b7f 100644 --- a/rust/pin-init/src/lib.rs +++ b/rust/pin-init/src/lib.rs @@ -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`. |