[PATCH v6 00/14] hrtimer Rust API

[Andreas Hindborg <a.hindborg@kernel.org>]

This series adds support for using the `hrtimer` subsystem from Rust code.

The series adds support for timer mode and clock source configuration during
timer initialization. Examples and functionality to execute closures at timer
expiration has been removed, as these depend on either atomics [3] or
`SpinLockIrq` [4], which are still being worked on.

This series is a dependency for unmerged features of the Rust null block driver
[1], and for rkvms [2].

Link: https://git.kernel.org/pub/scm/linux/kernel/git/a.hindborg/linux.git/log/?h=rnull-v6.11-rc2 [1]
Link: https://gitlab.freedesktop.org/lyudess/linux/-/tree/rvkms-wip [2]
Link: https://lore.kernel.org/rust-for-linux/20240612223025.1158537-1-boqun.feng@gmail.com/ [3]
Link: https://lore.kernel.org/rust-for-linux/20240916213025.477225-1-lyude@redhat.com/ [4]
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
Changes in v6:
- prefix all hrtimer related type names with `Hr`
- add a few links for type names in the documentation
- Link to v5: https://lore.kernel.org/r/20241217-hrtimer-v3-v6-12-rc2-v5-0-b34c20ac2cb7@kernel.org

Changes in v5:
- Fix a typo in `impl_has_timer`
- Implement `Box::into_pin` in terms of `impl From<Box> for Pin<Box>`
- Link to v4: https://lore.kernel.org/r/20241206-hrtimer-v3-v6-12-rc2-v4-0-6cb8c3673682@kernel.org

Changes in v4:
- rebase on v6.13-rc1 and adapt to kernel `Box`
- add a missing safety comment to `hrtimer::start`
- use `hrtimer_setup`
- fix a build issue when `bindings::hrtimer_restart` is signed
- fix a memory leak where box was not destroyed
- fix a documentation typo
- remove `as` coercion at multiple locations
- use fully qualified syntax when invoking `deref`
- move `hrtimer` into `time` module
- Link to v3: https://lore.kernel.org/r/20241017-hrtimer-v3-v6-12-rc2-v3-0-59a75cbb44da@kernel.org

Changes in v3:
- support timer mode selection
- support clock source selection
- eliminate `Arc::clone_from_raw` in favor of using `ArcBorrow`
- make `Arc::as_ptr` an associated method
- update safety requirement for `ArcBorrow::from_raw`
- remove examples (pending `SpinLockIrq` and `CondVar` patches)
- remove `start_function` (v2 `schedule_function`, pending `SpinLockIrq` and `CondVar` patches)
- change function naming from schedule/armed to start/running
- add vocabulary to documentation
- update safety comment in `Arc::as_ptr`
- Link to v2: https://lore.kernel.org/r/20240917222739.1298275-1-a.hindborg@kernel.org

Changes in v2:
- use a handle to own the timer callback target
- add ability to for callback to reschedule timer
- improve `impl_has_timer` to allow generics
- add support for stack allocated timers
- add support for scheduling closures
- use `Ktime` for setting expiration
- use `CondVar` instead of `AtomicBool` in examples
- rebase on 6.11
- improve documentation
- Link to v1: https://lore.kernel.org/r/20240425094634.262674-1-nmi@metaspace.dk

---
Andreas Hindborg (13):
      rust: hrtimer: introduce hrtimer support
      rust: sync: add `Arc::as_ptr`
      rust: hrtimer: implement `HrTimerPointer` for `Arc`
      rust: hrtimer: allow timer restart from timer handler
      rust: hrtimer: add `UnsafeHrTimerPointer`
      rust: hrtimer: add `hrtimer::ScopedHrTimerPointer`
      rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>`
      rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>`
      rust: alloc: add `Box::into_pin`
      rust: hrtimer: implement `HrTimerPointer` for `Pin<Box<T>>`
      rust: hrtimer: add `HrTimerMode`
      rust: hrtimer: add clocksource selection through `ClockSource`
      rust: hrtimer: add maintainer entry

Lyude Paul (1):
      rust: time: Add Ktime::from_ns()

 MAINTAINERS                         |  10 +
 rust/kernel/alloc/kbox.rs           |   6 +
 rust/kernel/sync/arc.rs             |  13 +-
 rust/kernel/time.rs                 |  10 +
 rust/kernel/time/hrtimer.rs         | 529 ++++++++++++++++++++++++++++++++++++
 rust/kernel/time/hrtimer/arc.rs     |  87 ++++++
 rust/kernel/time/hrtimer/pin.rs     |  95 +++++++
 rust/kernel/time/hrtimer/pin_mut.rs |  97 +++++++
 rust/kernel/time/hrtimer/tbox.rs    | 102 +++++++
 9 files changed, 947 insertions(+), 2 deletions(-)
---
base-commit: 8093380ff7bf546cf202531729705208911b87f1
change-id: 20241017-hrtimer-v3-v6-12-rc2-215dc6b169bf

Best regards,
-- 
Andreas Hindborg <a.hindborg@kernel.org>