linux/rust/kernel/str.rs, branch v6.17

rust: kernel: use `core::ffi::CStr` method names

2025-07-20T23:16:36Z

Prepare for `core::ffi::CStr` taking the place of `kernel::str::CStr` by avoiding methods that only exist on the latter. Also avoid `Deref for CStr` as that impl doesn't exist on `core::ffi::CStr`. Link: https://github.com/Rust-for-Linux/linux/issues/1075 Signed-off-by: Tamir Duberstein Reviewed-by: Benno Lossin Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-6-a91524037783@gmail.com [ Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

rust: str: add `CStr` methods matching `core::ffi::CStr`

2025-07-20T23:16:36Z

Prepare for replacing `CStr` with `core::ffi::CStr` by soft-deprecating methods which don't exist on `core::ffi::CStr`. We could keep `as_bytes{,_with_nul}` through an extension trait but seeing as we have to introduce `as_char_ptr_in_const_context` as a free function, we may as well introduce `to_bytes{,_with_nul}` here to allow downstream code to migrate in one cycle rather than two. Link: https://github.com/Rust-for-Linux/linux/issues/1075 Signed-off-by: Tamir Duberstein Reviewed-by: Benno Lossin Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-5-a91524037783@gmail.com [ Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

rust: str: remove unnecessary qualification

2025-07-20T23:16:36Z

`core::ffi::*` is in the prelude, which is imported here. Signed-off-by: Tamir Duberstein Reviewed-by: Benno Lossin Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-4-a91524037783@gmail.com Signed-off-by: Miguel Ojeda

rust: use `kernel::{fmt,prelude::fmt!}`

2025-07-20T23:16:35Z

Reduce coupling to implementation details of the formatting machinery by avoiding direct use for `core`'s formatting traits and macros. Signed-off-by: Tamir Duberstein Reviewed-by: Benno Lossin Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-3-a91524037783@gmail.com Signed-off-by: Miguel Ojeda

rust: kernel: remove `fmt!`, fix clippy::uninlined-format-args

2025-07-20T23:15:51Z

Rather than export a macro that delegates to `core::format_args`, simply re-export `core::format_args` as `fmt` from the prelude. This exposes clippy warnings which were previously obscured by this macro, such as: warning: variables can be used directly in the `format!` string --> ../drivers/cpufreq/rcpufreq_dt.rs:21:43 | 21 | let prop_name = CString::try_from_fmt(fmt!("{}-supply", name)).ok()?; | ^^^^^^^^^^^^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args = note: `-W clippy::uninlined-format-args` implied by `-W clippy::all` = help: to override `-W clippy::all` add `#[allow(clippy::uninlined_format_args)]` help: change this to | 21 - let prop_name = CString::try_from_fmt(fmt!("{}-supply", name)).ok()?; 21 + let prop_name = CString::try_from_fmt(fmt!("{name}-supply")).ok()?; | Thus fix them in the same commit. This could possibly be fixed in two stages, but the diff is small enough (outside of kernel/str.rs) that I hope it can be taken in a single commit. Signed-off-by: Tamir Duberstein Reviewed-by: Benno Lossin Reviewed-by: Alice Ryhl Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250704-core-cstr-prepare-v1-1-a91524037783@gmail.com Signed-off-by: Miguel Ojeda

rust: enable `clippy::ref_as_ptr` lint

2025-06-22T21:09:32Z

In Rust 1.78.0, Clippy introduced the `ref_as_ptr` lint [1]: > Using `as` casts may result in silently changing mutability or type. While this doesn't eliminate unchecked `as` conversions, it makes such conversions easier to scrutinize. It also has the slight benefit of removing a degree of freedom on which to bikeshed. Thus apply the changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#ref_as_ptr [1] Suggested-by: Benno Lossin Link: https://lore.kernel.org/all/D8PGG7NTWB6U.3SS3A5LN4XWMN@proton.me/ Reviewed-by: Benno Lossin Reviewed-by: Boqun Feng Signed-off-by: Tamir Duberstein Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-6-f43b024581e8@gmail.com Signed-off-by: Miguel Ojeda

rust: enable `clippy::as_underscore` lint

2025-06-22T21:09:17Z

In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]: > The conversion might include lossy conversion or a dangerous cast that > might go undetected due to the type being inferred. > > The lint is allowed by default as using `_` is less wordy than always > specifying the type. Always specifying the type is especially helpful in function call contexts where the inferred type may change at a distance. Specifying the type also allows Clippy to spot more cases of `useless_conversion`. The primary downside is the need to specify the type in trivial getters. There are 4 such functions: 3 have become slightly less ergonomic, 1 was revealed to be a `useless_conversion`. While this doesn't eliminate unchecked `as` conversions, it makes such conversions easier to scrutinize. It also has the slight benefit of removing a degree of freedom on which to bikeshed. Thus apply the changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1] Reviewed-by: Benno Lossin Reviewed-by: Boqun Feng Signed-off-by: Tamir Duberstein Acked-by: Greg Kroah-Hartman Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com [ Changed `isize` to `c_long`. - Miguel ] Signed-off-by: Miguel Ojeda

rust: enable `clippy::ptr_as_ptr` lint

2025-06-22T21:08:42Z

In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]: > Though `as` casts between raw pointers are not terrible, > `pointer::cast` is safer because it cannot accidentally change the > pointer's mutability, nor cast the pointer to other types like `usize`. There are a few classes of changes required: - Modules generated by bindgen are marked `#[allow(clippy::ptr_as_ptr)]`. - Inferred casts (` as _`) are replaced with `.cast()`. - Ascribed casts (` as *... T`) are replaced with `.cast::()`. - Multistep casts from references (` as *const _ as *const T`) are replaced with `core::ptr::from_ref(&x).cast()` with or without `::` according to the previous rules. The `core::ptr::from_ref` call is required because `(x as *const _).cast::()` results in inference failure. - Native literal C strings are replaced with `c_str!().as_char_ptr()`. - `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut T)`.cast();` since pointer to pointer can be confusing. Apply these changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1] Reviewed-by: Benno Lossin Reviewed-by: Boqun Feng Signed-off-by: Tamir Duberstein Acked-by: Viresh Kumar Acked-by: Greg Kroah-Hartman Acked-by: Tejun Heo Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-1-f43b024581e8@gmail.com [ Added `.cast()` for `opp`. - Miguel ] Signed-off-by: Miguel Ojeda

rust: str: take advantage of the `-> Result` support in KUnit `#[test]`'s

2025-05-27T18:09:59Z

Since now we have support for returning `-> Result`s, we can convert some of these tests to use the feature, and serve as a first user for it too. Thus convert them, which allows us to remove some `unwrap()`s. We keep the actual assertions we want to make as explicit ones with `assert*!`s. Reviewed-by: David Gow Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250502215133.1923676-6-ojeda@kernel.org [ Split the `CString` simplification into a new commit. - Miguel ] Signed-off-by: Miguel Ojeda

rust: str: simplify KUnit tests `format!` macro

2025-05-27T18:09:59Z

Simplify the `format!` macro used in the tests by using `CString::try_from_fmt` and directly `unwrap()`ing. This will allow us to change both `unwrap()`s here in order to showcase the `?` operator support now that the tests are KUnit ones. Reviewed-by: David Gow Acked-by: Danilo Krummrich [ Split from the next commit as suggested by Tamir. - Miguel ] Signed-off-by: Miguel Ojeda