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executor: Replace unsound critical sections with atomics

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This commit is contained in:
Grant Miller
2023-04-02 14:11:31 -05:00
parent eed2b12325
commit 8290236ed6
2 changed files with 25 additions and 21 deletions
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28
embassy-executor/src/raw/mod.rs
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@ -22,7 +22,6 @@ use core::ptr::NonNull;
use core::task::{Context, Poll};
use atomic_polyfill::{AtomicU32, Ordering};
use critical_section::CriticalSection;
#[cfg(feature = "integrated-timers")]
use embassy_time::driver::{self, AlarmHandle};
#[cfg(feature = "integrated-timers")]
@ -373,11 +372,11 @@ impl SyncExecutor {
/// - `task` must be set up to run in this executor.
/// - `task` must NOT be already enqueued (in this executor or another one).
#[inline(always)]
unsafe fn enqueue(&self, cs: CriticalSection, task: TaskRef) {
unsafe fn enqueue(&self, task: TaskRef) {
#[cfg(feature = "rtos-trace")]
trace::task_ready_begin(task.as_ptr() as u32);
if self.run_queue.enqueue(cs, task) {
if self.run_queue.enqueue(task) {
self.pender.pend();
}
}
@ -394,9 +393,7 @@ impl SyncExecutor {
#[cfg(feature = "rtos-trace")]
trace::task_new(task.as_ptr() as u32);
critical_section::with(|cs| {
self.enqueue(cs, task);
})
self.enqueue(task);
}
/// # Safety
@ -552,24 +549,25 @@ impl Executor {
///
/// You can obtain a `TaskRef` from a `Waker` using [`task_from_waker`].
pub fn wake_task(task: TaskRef) {
critical_section::with(|cs| {
let header = task.header();
let state = header.state.load(Ordering::Relaxed);
let header = task.header();
let res = header.state.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |state| {
// If already scheduled, or if not started,
if (state & STATE_RUN_QUEUED != 0) || (state & STATE_SPAWNED == 0) {
return;
None
} else {
// Mark it as scheduled
Some(state | STATE_RUN_QUEUED)
}
});
// Mark it as scheduled
header.state.store(state | STATE_RUN_QUEUED, Ordering::Relaxed);
if res.is_ok() {
// We have just marked the task as scheduled, so enqueue it.
unsafe {
let executor = header.executor.get().unwrap_unchecked();
executor.enqueue(cs, task);
executor.enqueue(task);
}
})
}
}
#[cfg(feature = "integrated-timers")]