linux-stable.git/rust/kernel/prelude.rs, branch v6.12.4

rust: init: add `write_[pin_]init` functions

2024-08-21T22:16:16+00:00

Sometimes it is necessary to split allocation and initialization into
two steps. One such situation is when reusing existing allocations
obtained via `Box::drop_contents`. See [1] for an example.

In order to support this use case add `write_[pin_]init` functions to the
pin-init API. These functions operate on already allocated smart
pointers that wrap `MaybeUninit`.

Link: https://lore.kernel.org/rust-for-linux/f026532f-8594-4f18-9aa5-57ad3f5bc592@proton.me/ [1]
Signed-off-by: Benno Lossin 
Reviewed-by: Boqun Feng 
Reviewed-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Link: https://lore.kernel.org/r/20240819112415.99810-2-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda

rust: alloc: introduce the `BoxExt` trait

2024-04-16T20:47:20+00:00

Make fallible versions of `new` and `new_uninit` methods available in
`Box` even though it doesn't implement them because we build `alloc`
with the `no_global_oom_handling` config.

They also have an extra `flags` parameter that allows callers to pass
flags to the allocator.

Signed-off-by: Wedson Almeida Filho 
Reviewed-by: Boqun Feng 
Reviewed-by: Benno Lossin 
Link: https://lore.kernel.org/r/20240328013603.206764-7-wedsonaf@gmail.com
[ Used `Box::write()` to avoid one `unsafe` block as suggested by Boqun. ]
Signed-off-by: Miguel Ojeda

rust: alloc: introduce allocation flags

2024-04-16T20:05:06+00:00

We'll use them when allocating `Box`, `Arc`, and `UniqueArc` instances,
as well as when allocating memory for `Vec` elements. These changes will
come in subsequent patches.

Reviewed-by: Benno Lossin 
Signed-off-by: Wedson Almeida Filho 
Link: https://lore.kernel.org/r/20240328013603.206764-6-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda

rust: alloc: introduce the `VecExt` trait

2024-04-16T20:03:14+00:00

Make `try_with_capacity`, `try_push`, and `try_extend_from_slice`
methods available in `Vec` even though it doesn't implement them. It is
implemented with `try_reserve` and `push_within_capacity`.

This is in preparation for switching to the upstream `alloc` crate.

Reviewed-by: Benno Lossin 
Suggested-by: Gary Guo 
Signed-off-by: Wedson Almeida Filho 
Link: https://lore.kernel.org/r/20240328013603.206764-3-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda

rust: add derive macro for `Zeroable`

2023-08-21T12:31:48+00:00

Add a derive proc-macro for the `Zeroable` trait. The macro supports
structs where every field implements the `Zeroable` trait. This way
`unsafe` implementations can be avoided.

The macro is split into two parts:
- a proc-macro to parse generics into impl and ty generics,
- a declarative macro that expands to the impl block.

Suggested-by: Asahi Lina 
Signed-off-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Martin Rodriguez Reboredo 
Link: https://lore.kernel.org/r/20230814084602.25699-4-benno.lossin@proton.me
[ Added `ignore` to the `lib.rs` example and cleaned trivial nit. ]
Signed-off-by: Miguel Ojeda

rust: introduce `current`

2023-04-21T22:20:00+00:00

This allows Rust code to get a reference to the current task without
having to increment the refcount, but still guaranteeing memory safety.

Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Reviewed-by: Martin Rodriguez Reboredo 
Signed-off-by: Wedson Almeida Filho 
Link: https://lore.kernel.org/r/20230411054543.21278-10-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda

rust: prelude: add `pin-init` API items to prelude

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

Add `pin-init` API macros and traits to the prelude.

Signed-off-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Alice Ryhl 
Reviewed-by: Andreas Hindborg 
Link: https://lore.kernel.org/r/20230408122429.1103522-13-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda

rust: prelude: prevent doc inline of external imports

2023-01-16T22:49:46+00:00

This shows exactly where the items are from, previously the items from
macros, alloc and core were shown as a declaration from the kernel crate,
this shows the correct path.

Link: https://github.com/rust-lang/rust/issues/106713
Signed-off-by: Finn Behrens 
Reviewed-by: Vincenzo Palazzo 
[Reworded to add Link, fixed two typos and comment style]
Signed-off-by: Miguel Ojeda

rust: build_assert: add `build_{error,assert}!` macros

2022-12-04T00:59:16+00:00

Add the `build_error!` and `build_assert!` macros which leverage
the previously introduced `build_error` crate. Do so in a new
module, called `build_assert`.

The former fails the build if the code path calling it can possibly
be executed. The latter asserts that a boolean expression is `true`
at compile time.

In particular, `build_assert!` can be used in some contexts where
`static_assert!` cannot:

    fn f1() {
        static_assert!(N > 1);` // Error.
        build_assert!(N > 1);   // Build-time check.
        assert!(N > 1);         // Run-time check.
    }

    #[inline]
    fn f2(n: usize) {
        static_assert!(n > 1);  // Error.
        build_assert!(n > 1);   // Build-time check.
        assert!(n > 1);         // Run-time check.
    }

Signed-off-by: Gary Guo 
Reviewed-by: Wei Liu 
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda

rust: static_assert: add `static_assert!` macro

2022-12-04T00:59:16+00:00

Add the `static_assert!` macro, which is a compile-time assert, similar
to the C11 `_Static_assert` and C++11 `static_assert` declarations [1,2].
Do so in a new module, called `static_assert`.

For instance:

    static_assert!(42 > 24);
    static_assert!(core::mem::size_of::() == 1);

    const X: &[u8] = b"bar";
    static_assert!(X[1] == b'a');

    const fn f(x: i32) -> i32 {
        x + 2
    }
    static_assert!(f(40) == 42);

Link: https://en.cppreference.com/w/c/language/_Static_assert [1]
Link: https://en.cppreference.com/w/cpp/language/static_assert [2]
Co-developed-by: Alex Gaynor 
Signed-off-by: Alex Gaynor 
Signed-off-by: Miguel Ojeda