diff options
| -rw-r--r-- | rust/kernel/init.rs | 9 | ||||
| -rw-r--r-- | rust/kernel/types.rs | 20 |
2 files changed, 29 insertions, 0 deletions
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index ffd539e2f5ef..a1298c8bbda0 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -177,6 +177,14 @@ //! } //! ``` //! +//! For the special case where initializing a field is a single FFI-function call that cannot fail, +//! there exist the helper function [`Opaque::ffi_init`]. This function initialize a single +//! [`Opaque`] field by just delegating to the supplied closure. You can use these in combination +//! with [`pin_init!`]. +//! +//! For more information on how to use [`pin_init_from_closure()`], take a look at the uses inside +//! the `kernel` crate. The [`sync`] module is a good starting point. +//! //! [`sync`]: kernel::sync //! [pinning]: https://doc.rust-lang.org/std/pin/index.html //! [structurally pinned fields]: @@ -187,6 +195,7 @@ //! [`impl PinInit<T, E>`]: PinInit //! [`impl Init<T, E>`]: Init //! [`Opaque`]: kernel::types::Opaque +//! [`Opaque::ffi_init`]: kernel::types::Opaque::ffi_init //! [`pin_data`]: ::macros::pin_data use crate::{ diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs index ff2b2fac951d..a4b1e3778da7 100644 --- a/rust/kernel/types.rs +++ b/rust/kernel/types.rs @@ -2,6 +2,7 @@ //! Kernel types. +use crate::init::{self, PinInit}; use alloc::boxed::Box; use core::{ cell::UnsafeCell, @@ -234,6 +235,25 @@ impl<T> Opaque<T> { Self(MaybeUninit::uninit()) } + /// 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 + /// `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 ffi_init(init_func: impl FnOnce(*mut T)) -> impl PinInit<Self> { + // 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::<_, ::core::convert::Infallible>(move |slot| { + init_func(Self::raw_get(slot)); + Ok(()) + }) + } + } + /// Returns a raw pointer to the opaque data. pub fn get(&self) -> *mut T { UnsafeCell::raw_get(self.0.as_ptr()) |