// SPDX-License-Identifier: GPL-2.0 use super::HasHrTimer; use super::HrTimer; use super::HrTimerCallback; use super::HrTimerHandle; use super::HrTimerPointer; use super::RawHrTimerCallback; use crate::sync::Arc; use crate::sync::ArcBorrow; use crate::time::Ktime; /// A handle for an `Arc>` returned by a call to /// [`HrTimerPointer::start`]. pub struct ArcHrTimerHandle where T: HasHrTimer, { pub(crate) inner: Arc, } // SAFETY: We implement drop below, and we cancel the timer in the drop // implementation. unsafe impl HrTimerHandle for ArcHrTimerHandle where T: HasHrTimer, { fn cancel(&mut self) -> bool { let self_ptr = Arc::as_ptr(&self.inner); // SAFETY: As we obtained `self_ptr` from a valid reference above, it // must point to a valid `T`. let timer_ptr = unsafe { >::raw_get_timer(self_ptr) }; // SAFETY: As `timer_ptr` points into `T` and `T` is valid, `timer_ptr` // must point to a valid `HrTimer` instance. unsafe { HrTimer::::raw_cancel(timer_ptr) } } } impl Drop for ArcHrTimerHandle where T: HasHrTimer, { fn drop(&mut self) { self.cancel(); } } impl HrTimerPointer for Arc where T: 'static, T: Send + Sync, T: HasHrTimer, T: for<'a> HrTimerCallback = Self>, { type TimerHandle = ArcHrTimerHandle; fn start(self, expires: Ktime) -> ArcHrTimerHandle { // SAFETY: // - We keep `self` alive by wrapping it in a handle below. // - Since we generate the pointer passed to `start` from a valid // reference, it is a valid pointer. unsafe { T::start(Arc::as_ptr(&self), expires) }; ArcHrTimerHandle { inner: self } } } impl RawHrTimerCallback for Arc where T: 'static, T: HasHrTimer, T: for<'a> HrTimerCallback = Self>, { type CallbackTarget<'a> = ArcBorrow<'a, T>; unsafe extern "C" fn run(ptr: *mut bindings::hrtimer) -> bindings::hrtimer_restart { // `HrTimer` is `repr(C)` let timer_ptr = ptr.cast::>(); // SAFETY: By C API contract `ptr` is the pointer we passed when // queuing the timer, so it is a `HrTimer` embedded in a `T`. let data_ptr = unsafe { T::timer_container_of(timer_ptr) }; // SAFETY: // - `data_ptr` is derived form the pointer to the `T` that was used to // queue the timer. // - As per the safety requirements of the trait `HrTimerHandle`, the // `ArcHrTimerHandle` associated with this timer is guaranteed to // be alive until this method returns. That handle borrows the `T` // behind `data_ptr` thus guaranteeing the validity of // the `ArcBorrow` created below. // - We own one refcount in the `ArcTimerHandle` associated with this // timer, so it is not possible to get a `UniqueArc` to this // allocation from other `Arc` clones. let receiver = unsafe { ArcBorrow::from_raw(data_ptr) }; T::run(receiver).into_c() } }