kernel/linux.git/rust/macros/pin_data.rs, branch v6.12.80

rust: macros: allow generic parameter default values in `#[pin_data]`

2024-04-07T20:03:42+00:00

Add support for generic parameters defaults in `#[pin_data]` by using the newly introduced `decl_generics` instead of the `impl_generics`. Before this would not compile: #[pin_data] struct Foo { // ... } because it would be expanded to this: struct Foo { // ... } const _: () = { struct __ThePinData { __phantom: ::core::marker::PhantomData) -> Foo>, } impl ::core::clone::Clone for __ThePinData { fn clone(&self) -> Self { *self } } // [...] rest of expansion omitted }; The problem is with the `impl`, since that is invalid Rust syntax. It should not mention the default value at all, since default values only make sense on type definitions. The new `impl_generics` do not contain the default values, thus generating correct Rust code. This is used by the next commit that puts `#[pin_data]` on `kernel::workqueue::Work`. Signed-off-by: Benno Lossin Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Gary Guo Reviewed-by: Alice Ryhl Tested-by: Alice Ryhl Link: https://lore.kernel.org/r/20240309155243.482334-2-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: macros: add `decl_generics` to `parse_generics()`

2024-04-07T20:03:42+00:00

The generic parameters on a type definition can specify default values. Currently `parse_generics()` cannot handle this though. For example when parsing the following generics: The `impl_generics` will be set to `T: Clone, const N: usize = 0` and `ty_generics` will be set to `T, N`. Now using the `impl_generics` on an impl block: impl<$($impl_generics)*> Foo {} will result in invalid Rust code, because default values are only available on type definitions. Therefore add parsing support for generic parameter default values using a new kind of generics called `decl_generics` and change the old behavior of `impl_generics` to not contain the generic parameter default values. Now `Generics` has three fields: - `impl_generics`: the generics with bounds (e.g. `T: Clone, const N: usize`) - `decl_generics`: the generics with bounds and default values (e.g. `T: Clone, const N: usize = 0`) - `ty_generics`: contains the generics without bounds and without default values (e.g. `T, N`) `impl_generics` is designed to be used on `impl<$impl_generics>`, `decl_generics` for the type definition, so `struct Foo<$decl_generics>` and `ty_generics` whenever you use the type, so `Foo<$ty_generics>`. Here is an example that uses all three different types of generics: let (Generics { decl_generics, impl_generics, ty_generics }, rest) = parse_generics(input); quote! { struct Foo<$($decl_generics)*> { // ... } impl<$impl_generics> Foo<$ty_generics> { fn foo() { // ... } } } The next commit contains a fix to the `#[pin_data]` macro making it compatible with generic parameter default values by relying on this new behavior. Signed-off-by: Benno Lossin Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20240309155243.482334-1-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: macros: replace Self with the concrete type in #[pin_data]

2023-05-31T16:53:09+00:00

When using `#[pin_data]` on a struct that used `Self` in the field types, a type error would be emitted when trying to use `pin_init!`. Since an internal type would be referenced by `Self` instead of the defined struct. This patch fixes this issue by replacing all occurrences of `Self` in the `#[pin_data]` macro with the concrete type circumventing the issue. Since rust allows type definitions inside of blocks, which are expressions, the macro also checks for these and emits a compile error when it finds `trait`, `enum`, `union`, `struct` or `impl`. These keywords allow creating new `Self` contexts, which conflicts with the current implementation of replacing every `Self` ident. If these were allowed, some `Self` idents would be replaced incorrectly. Signed-off-by: Benno Lossin Reported-by: Alice Ryhl Reviewed-by: Alice Ryhl Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Gary Guo Link: https://lore.kernel.org/r/20230424081112.99890-3-benno.lossin@proton.me [ Added newline in commit message ] Signed-off-by: Miguel Ojeda

rust: macros: refactor generics parsing of `#[pin_data]` into its own function

2023-05-31T16:53:09+00:00

Other macros might also want to parse generics. Additionally this makes the code easier to read, as the next commit will introduce more code in `#[pin_data]`. Also add more comments to explain how parsing generics work. Signed-off-by: Benno Lossin Reviewed-by: Alice Ryhl Reviewed-by: Gary Guo Reviewed-by: Martin Rodriguez Reboredo Link: https://lore.kernel.org/r/20230424081112.99890-2-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: init: add initialization macros

2023-04-12T16:41:05+00:00

Add the following initializer macros: - `#[pin_data]` to annotate structurally pinned fields of structs, needed for `pin_init!` and `try_pin_init!` to select the correct initializer of fields. - `pin_init!` create a pin-initializer for a struct with the `Infallible` error type. - `try_pin_init!` create a pin-initializer for a struct with a custom error type (`kernel::error::Error` is the default). - `init!` create an in-place-initializer for a struct with the `Infallible` error type. - `try_init!` create an in-place-initializer for a struct with a custom error type (`kernel::error::Error` is the default). Also add their needed internal helper traits and structs. Co-developed-by: Gary Guo Signed-off-by: Gary Guo Signed-off-by: Benno Lossin Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Link: https://lore.kernel.org/r/20230408122429.1103522-8-y86-dev@protonmail.com [ Fixed three typos. ] Signed-off-by: Miguel Ojeda