On Tue, Oct 1, 2024 at 3:23 AM Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote:
>
> This will be used by the miscdevice abstractions, as the C function
> `misc_register` is fallible.
>
> Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
> ---
> rust/kernel/types.rs | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
> index 9e7ca066355c..070d03152937 100644
> --- a/rust/kernel/types.rs
> +++ b/rust/kernel/types.rs
> @@ -299,6 +299,22 @@ pub fn ffi_init(init_func: impl FnOnce(*mut T)) -> impl PinInit<Self> {
> }
> }
>
> + /// Creates a fallible pin-initializer from the given initializer closure.
> + ///
> + /// The returned initializer calls the given closure with the pointer to the inner `T` of this
> + /// `Opaque`. Since this memory is uninitialized, the closure is not allowed to read from it.
> + ///
> + /// This function is safe, because the `T` inside of an `Opaque` is allowed to be
> + /// uninitialized. Additionally, access to the inner `T` requires `unsafe`, so the caller needs
> + /// to verify at that point that the inner value is valid.
> + pub fn try_ffi_init<E>(
> + init_func: impl FnOnce(*mut T) -> Result<(), E>,
> + ) -> impl PinInit<Self, E> {
> + // SAFETY: We contain a `MaybeUninit`, so it is OK for the `init_func` to not fully
> + // initialize the `T`.
> + unsafe { init::pin_init_from_closure::<_, E>(move |slot| init_func(Self::raw_get(slot))) }
> + }
[1] adjusts `ffi_init` to use `try_ffi_init`. Maybe this should do the same?
[1]: https://lore.kernel.org/rust-for-linux/20241022213221.2383-2-dakr@xxxxxxxxxx/
