linux/rust/kernel/sync/arc.rs, branch v6.15

Merge tag 'rust-hrtimer-for-v6.15-v3' of https://github.com/Rust-for-Linux/linux into rust-next

2025-03-25T22:41:14Z

Pull rust-hrtimer updates from Andreas Hindborg: "Introduce Rust support for the 'hrtimer' subsystem: - Add a way to use the 'hrtimer' subsystem from Rust. Rust code can now set up intrusive timers without allocating when starting the timer. - Add support for 'Pin>', 'Arc<_>', 'Pin<&_>' and 'Pin<&mut _>' as pointer types for use with timer callbacks. - Add support for setting clock source and timer mode. 'kernel' crate: - Add 'Arc::as_ptr' for converting an 'Arc' to a raw pointer. This is a dependency for the 'hrtimer' API. - Add 'Box::into_pin' for converting a 'Box<_>' into a 'Pin>' to align with Rust 'alloc'. This is a dependency for the 'hrtimer' API." * tag 'rust-hrtimer-for-v6.15-v3' of https://github.com/Rust-for-Linux/linux: rust: hrtimer: add maintainer entry rust: hrtimer: add clocksource selection through `ClockId` rust: hrtimer: add `HrTimerMode` rust: hrtimer: implement `HrTimerPointer` for `Pin>` rust: alloc: add `Box::into_pin` rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>` rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>` rust: hrtimer: add `hrtimer::ScopedHrTimerPointer` rust: hrtimer: add `UnsafeHrTimerPointer` rust: hrtimer: allow timer restart from timer handler rust: hrtimer: implement `HrTimerPointer` for `Arc` rust: sync: add `Arc::as_ptr` rust: hrtimer: introduce hrtimer support

rust: make pin-init its own crate

2025-03-16T20:59:19Z

Rename relative paths inside of the crate to still refer to the same items, also rename paths inside of the kernel crate and adjust the build system to build the crate. [ Remove the `expect` (and thus the `lint_reasons` feature) since the tree now uses `quote!` from `rust/macros/export.rs`. Remove the `TokenStream` import removal, since it is now used as well. In addition, temporarily (i.e. just for this commit) use an `--extern force:alloc` to prevent an unknown `new_uninit` error in the `rustdoc` target. For context, please see a similar case in: https://lore.kernel.org/lkml/20240422090644.525520-1-ojeda@kernel.org/ And adjusted the message above. - Miguel ] Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-16-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: pin-init: move `InPlaceInit` and impls of `InPlaceWrite` into the kernel crate

2025-03-16T20:59:18Z

In order to make pin-init a standalone crate, move kernel-specific code directly into the kernel crate. This includes the `InPlaceInit` trait, its implementations and the implementations of `InPlaceWrite` for `Arc` and `UniqueArc`. All of these use the kernel's error type which will become unavailable in pin-init. Signed-off-by: Benno Lossin Reviewed-by: Fiona Behrens Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20250308110339.2997091-9-benno.lossin@proton.me Signed-off-by: Miguel Ojeda

rust: sync: add `Arc::as_ptr`

2025-03-11T20:00:42Z

Add a method to get a pointer to the data contained in an `Arc`. Reviewed-by: Lyude Paul Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Link: https://lore.kernel.org/r/20250309-hrtimer-v3-v6-12-rc2-v12-2-73586e2bd5f1@kernel.org Signed-off-by: Andreas Hindborg

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: reorder `ForeignOwnable` items

2025-01-13T22:45:54Z

`{into,from}_foreign` before `borrow` is slightly more logical. This removes an inconsistency with `kbox.rs` which already uses this ordering. Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Signed-off-by: Tamir Duberstein Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-5-80dbadd00951@gmail.com [ 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: arc: split unsafe block, add missing comment

2025-01-13T22:45:31Z

The new SAFETY comment style is taken from existing comments in `deref` and `drop. Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Signed-off-by: Tamir Duberstein Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-3-80dbadd00951@gmail.com 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: arc: use `NonNull::new_unchecked`

2025-01-13T22:45:30Z

There is no need to check (and panic on violations of) the safety requirements on `ForeignOwnable` functions. Avoiding the check is consistent with the implementation of `ForeignOwnable` for `Box`. Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Signed-off-by: Tamir Duberstein Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-1-80dbadd00951@gmail.com Signed-off-by: Miguel Ojeda