linux/rust/kernel/alloc, branch v6.14

rust: alloc: satisfy POSIX alignment requirement

2025-03-05T22:57:48Z

ISO C's `aligned_alloc` is partially implementation-defined; on some systems it inherits stricter requirements from POSIX's `posix_memalign`. This causes the call added in commit dd09538fb409 ("rust: alloc: implement `Cmalloc` in module allocator_test") to fail on macOS because it doesn't meet the requirements of `posix_memalign`. Adjust the call to meet the POSIX requirement and add a comment. This fixes failures in `make rusttest` on macOS. Acked-by: Danilo Krummrich Cc: stable@vger.kernel.org Fixes: dd09538fb409 ("rust: alloc: implement `Cmalloc` in module allocator_test") Signed-off-by: Tamir Duberstein Reviewed-by: Gary Guo Link: https://lore.kernel.org/r/20250213-aligned-alloc-v7-1-d2a2d0be164b@gmail.com [ Added Cc: stable. - Miguel ] Signed-off-by: Miguel Ojeda

rust: kernel: add improved version of `ForeignOwnable::borrow_mut`

2025-01-13T22:46:07Z

Previously, the `ForeignOwnable` trait had a method called `borrow_mut` that was intended to provide mutable access to the inner value. However, the method accidentally made it possible to change the address of the object being modified, which usually isn't what we want. (And when we want that, it can be done by calling `from_foreign` and `into_foreign`, like how the old `borrow_mut` was implemented.) In this patch, we introduce an alternate definition of `borrow_mut` that solves the previous problem. Conceptually, given a pointer type `P` that implements `ForeignOwnable`, the `borrow_mut` method gives you the same kind of access as an `&mut P` would, except that it does not let you change the pointer `P` itself. This is analogous to how the existing `borrow` method provides the same kind of access to the inner value as an `&P`. Note that for types like `Arc`, having an `&mut Arc` only gives you immutable access to the inner `T`. This is because mutable references assume exclusive access, but there might be other handles to the same reference counted value, so the access isn't exclusive. The `Arc` type implements this by making `borrow_mut` return the same type as `borrow`. Signed-off-by: Alice Ryhl Reviewed-by: Boqun Feng Reviewed-by: Benno Lossin Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Andreas Hindborg Signed-off-by: Tamir Duberstein Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-6-80dbadd00951@gmail.com [ Updated to `crate::ffi::`. Reworded title slightly. - Miguel ] Signed-off-by: Miguel Ojeda

rust: kernel: change `ForeignOwnable` pointer to mut

2025-01-13T22:45:31Z

It is slightly more convenient to operate on mut pointers, and this also properly conveys the desired ownership semantics of the trait. Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Signed-off-by: Tamir Duberstein Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-4-80dbadd00951@gmail.com [ Reworded title slightly. - Miguel ] Signed-off-by: Miguel Ojeda

rust: types: avoid `as` casts

2025-01-13T22:45:30Z

Replace `as` casts with `cast{,_mut}` calls which are a bit safer. In one instance, remove an unnecessary `as` cast without replacement. Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Signed-off-by: Tamir Duberstein Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-2-80dbadd00951@gmail.com Signed-off-by: Miguel Ojeda

rust: alloc: add doctest for `ArrayLayout::new()`

2025-01-13T22:45:30Z

Add a rustdoc example and Kunit test to the `ArrayLayout` struct's `ArrayLayout::new()` function. This patch depends on the first patch in this series in order for the KUnit test to compile. Suggested-by: Boqun Feng Link: https://github.com/Rust-for-Linux/linux/issues/1131 Reviewed-by: Danilo Krummrich Signed-off-by: Jimmy Ostler Link: https://lore.kernel.org/r/f1564da5bcaa6be87aee312767a1d1694a03d1b7.1734674670.git.jtostler1@gmail.com [ Added periods to example comments. Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

rust: alloc: align Debug implementation for Box with Display

2024-12-17T23:56:05Z

Ensure consistency between `Debug` and `Display` for `Box` by updating `Debug` to match the new `Display` style. Acked-by: Danilo Krummrich Signed-off-by: Guangbo Cui <2407018371@qq.com> Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/tencent_1FC0BC283DA65DD81A8A14EEF25563934E05@qq.com [ Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

rust: alloc: implement Display for Box

2024-12-17T23:54:31Z

Currently `impl Display` is missing for `Box`, as a result, things like using `Box<..>` directly as an operand in `pr_info!()` are impossible, which is less ergonomic compared to `Box` in Rust std. Therefore add `impl Display` for `Box`. Acked-by: Danilo Krummrich Suggested-by: Boqun Feng Link: https://github.com/Rust-for-Linux/linux/issues/1126 Signed-off-by: Guangbo Cui <2407018371@qq.com> Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/tencent_2AD25C6A6898D3A598CBA54BB6AF59BB900A@qq.com [ Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

rust: alloc: Fix `ArrayLayout` allocations

2024-11-24T23:11:07Z

We were accidentally allocating a layout for the *square* of the object size due to a variable shadowing mishap. Fixes memory bloat and page allocation failures in drm/asahi. Reported-by: Janne Grunau Fixes: 9e7bbfa18276 ("rust: alloc: introduce `ArrayLayout`") Signed-off-by: Asahi Lina Acked-by: Danilo Krummrich Reviewed-by: Neal Gompa Link: https://lore.kernel.org/r/20241123-rust-fix-arraylayout-v1-1-197e64c95bd4@asahilina.net Signed-off-by: Miguel Ojeda

rust: use custom FFI integer types

2024-11-10T22:58:00Z

Currently FFI integer types are defined in libcore. This commit creates the `ffi` crate and asks bindgen to use that crate for FFI integer types instead of `core::ffi`. This commit is preparatory and no type changes are made in this commit yet. Signed-off-by: Gary Guo Link: https://lore.kernel.org/r/20240913213041.395655-4-gary@garyguo.net [ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of `rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate docs slightly and formatted. - Miguel ] Signed-off-by: Miguel Ojeda

kbuild: rust: remove the `alloc` crate and `GlobalAlloc`

2024-10-15T21:10:32Z

Now that we have our own `Allocator`, `Box` and `Vec` types we can remove Rust's `alloc` crate and the `new_uninit` unstable feature. Also remove `Kmalloc`'s `GlobalAlloc` implementation -- we can't remove this in a separate patch, since the `alloc` crate requires a `#[global_allocator]` to set, that implements `GlobalAlloc`. Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-29-dakr@kernel.org Signed-off-by: Miguel Ojeda