Messages in this thread Patch in this message | | | Date | Fri, 31 Mar 2023 21:54:29 +0000 | From | y86-dev@protonma ... | Subject | [PATCH v4 13/15] rust: types: add common init-helper functions for `Opaque` |
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From: Benno Lossin <y86-dev@protonmail.com>
Add helper functions to more easily initialize `Opaque<T>` via FFI and rust raw initializer functions. These functions take a function pointer to the FFI/raw initialization function and take between 0-4 other arguments. It then returns an initializer that uses the FFI/raw initialization function along with the given arguments to initialize an `Opaque<T>`.
Signed-off-by: Benno Lossin <y86-dev@protonmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Cc: Gary Guo <gary@garyguo.net> --- rust/kernel/init.rs | 9 +++++++++ rust/kernel/types.rs | 47 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+)
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index fef14c3c0642..7b452e458391 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 helper functions [`Opaque::ffi_init`]. These functions initialize a single +//! [`Opaque`] field by just delegating to the FFI-function. 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..dbfae9bb97ce 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, @@ -248,6 +249,52 @@ impl<T> Opaque<T> { } }
+macro_rules! opaque_init_funcs { + ($($abi:literal $name:ident($($arg_name:ident: $arg_typ:ident),*);)*) => { + impl<T> Opaque<T> { + $( + /// Create an initializer using the given initializer function. + /// + /// # Safety + /// + /// The given function **must** under all circumstances initialize the memory + /// location to a valid `T`. If it fails to do so it results in UB. + /// + /// If any parameters are given, those need to be valid for the function. Valid + /// means that calling the function with those parameters complies with the above + /// requirement **and** every other requirement on the function itself. + pub unsafe fn $name<$($arg_typ),*>( + init_func: unsafe extern $abi fn(*mut T $(, $arg_typ)*), + $($arg_name: $arg_typ,)* + ) -> impl PinInit<Self> { + // SAFETY: The safety contract of this function ensures that `init_func` fully + // initializes `slot`. + unsafe { + init::pin_init_from_closure(move |slot| { + init_func(Self::raw_get(slot) $(, $arg_name)*); + Ok(()) + }) + } + } + )* + } + } +} + +opaque_init_funcs! { + "C" ffi_init(); + "C" ffi_init1(arg1: A1); + "C" ffi_init2(arg1: A1, arg2: A2); + "C" ffi_init3(arg1: A1, arg2: A2, arg3: A3); + "C" ffi_init4(arg1: A1, arg2: A2, arg3: A3, arg4: A4); + + "Rust" manual_init(); + "Rust" manual_init1(arg1: A1); + "Rust" manual_init2(arg1: A1, arg2: A2); + "Rust" manual_init3(arg1: A1, arg2: A2, arg3: A3); + "Rust" manual_init4(arg1: A1, arg2: A2, arg3: A3, arg4: A4); +} + /// A sum type that always holds either a value of type `L` or `R`. pub enum Either<L, R> { /// Constructs an instance of [`Either`] containing a value of type `L`. -- 2.39.2
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