Re: [PATCH v7 05/16] rust: types: add `Opaque::pin_init`

Gary Guo
2024-12-24T20:21:28Z

On Thu, 19 Dec 2024 18:04:07 +0100
Danilo Krummrich <dakr@kernel.org> wrote:

> Analogous to `Opaque::new` add `Opaque::pin_init`, which instead of a
> value `T` takes a `PinInit<T>` and returns a `PinInit<Opaque<T>>`.
>
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Suggested-by: Alice Ryhl <aliceryhl@google.com>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Reviewed-by: Gary Guo <gary@garyguo.net>

> ---
> rust/kernel/types.rs | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
> index ec6457bb3084..3aea6af9a0bc 100644
> --- a/rust/kernel/types.rs
> +++ b/rust/kernel/types.rs
> @@ -281,6 +281,17 @@ pub const fn uninit() -> Self {
> }
> }
>
> + /// Create an opaque pin-initializer from the given pin-initializer.
> + pub fn pin_init(slot: impl PinInit<T>) -> impl PinInit<Self> {
> + Self::ffi_init(|ptr: *mut T| {
> + // SAFETY:
> + // - `ptr` is a valid pointer to uninitialized memory,
> + // - `slot` is not accessed on error; the call is infallible,
> + // - `slot` is pinned in memory.
> + let _ = unsafe { init::PinInit::<T>::__pinned_init(slot, ptr) };
> + })
> + }
> +
> /// Creates a pin-initializer from the given initializer closure.
> ///
> /// The returned initializer calls the given closure with the pointer to the inner `T` of this