1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
// SPDX-License-Identifier: GPL-2.0
use super::HasHrTimer;
use super::HrTimer;
use super::HrTimerCallback;
use super::HrTimerHandle;
use super::RawHrTimerCallback;
use super::UnsafeHrTimerPointer;
use crate::time::Ktime;
use core::pin::Pin;
/// A handle for a `Pin<&HasHrTimer>`. When the handle exists, the timer might be
/// running.
pub struct PinHrTimerHandle<'a, T>
where
T: HasHrTimer<T>,
{
pub(crate) inner: Pin<&'a T>,
}
// SAFETY: We cancel the timer when the handle is dropped. The implementation of
// the `cancel` method will block if the timer handler is running.
unsafe impl<'a, T> HrTimerHandle for PinHrTimerHandle<'a, T>
where
T: HasHrTimer<T>,
{
fn cancel(&mut self) -> bool {
let self_ptr: *const T = self.inner.get_ref();
// SAFETY: As we got `self_ptr` from a reference above, it must point to
// a valid `T`.
let timer_ptr = unsafe { <T as HasHrTimer<T>>::raw_get_timer(self_ptr) };
// SAFETY: As `timer_ptr` is derived from a reference, it must point to
// a valid and initialized `HrTimer`.
unsafe { HrTimer::<T>::raw_cancel(timer_ptr) }
}
}
impl<'a, T> Drop for PinHrTimerHandle<'a, T>
where
T: HasHrTimer<T>,
{
fn drop(&mut self) {
self.cancel();
}
}
// SAFETY: We capture the lifetime of `Self` when we create a `PinHrTimerHandle`,
// so `Self` will outlive the handle.
unsafe impl<'a, T> UnsafeHrTimerPointer for Pin<&'a T>
where
T: Send + Sync,
T: HasHrTimer<T>,
T: HrTimerCallback<Pointer<'a> = Self>,
{
type TimerHandle = PinHrTimerHandle<'a, T>;
unsafe fn start(self, expires: Ktime) -> Self::TimerHandle {
// Cast to pointer
let self_ptr: *const T = self.get_ref();
// SAFETY:
// - As we derive `self_ptr` from a reference above, it must point to a
// valid `T`.
// - We keep `self` alive by wrapping it in a handle below.
unsafe { T::start(self_ptr, expires) };
PinHrTimerHandle { inner: self }
}
}
impl<'a, T> RawHrTimerCallback for Pin<&'a T>
where
T: HasHrTimer<T>,
T: HrTimerCallback<Pointer<'a> = Self>,
{
type CallbackTarget<'b> = Self;
unsafe extern "C" fn run(ptr: *mut bindings::hrtimer) -> bindings::hrtimer_restart {
// `HrTimer` is `repr(C)`
let timer_ptr = ptr as *mut HrTimer<T>;
// SAFETY: By the safety requirement of this function, `timer_ptr`
// points to a `HrTimer<T>` contained in an `T`.
let receiver_ptr = unsafe { T::timer_container_of(timer_ptr) };
// SAFETY:
// - By the safety requirement of this function, `timer_ptr`
// points to a `HrTimer<T>` contained in an `T`.
// - As per the safety requirements of the trait `HrTimerHandle`, the
// `PinHrTimerHandle` associated with this timer is guaranteed to
// be alive until this method returns. That handle borrows the `T`
// behind `receiver_ptr`, thus guaranteeing the validity of
// the reference created below.
let receiver_ref = unsafe { &*receiver_ptr };
// SAFETY: `receiver_ref` only exists as pinned, so it is safe to pin it
// here.
let receiver_pin = unsafe { Pin::new_unchecked(receiver_ref) };
T::run(receiver_pin).into_c()
}
}
|
