From 8290236ed64435453a9c028c95246a86371bd4ce Mon Sep 17 00:00:00 2001 From: Grant Miller Date: Sun, 2 Apr 2023 14:11:31 -0500 Subject: executor: Replace unsound critical sections with atomics --- embassy-executor/src/raw/run_queue.rs | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'embassy-executor/src/raw/run_queue.rs') diff --git a/embassy-executor/src/raw/run_queue.rs b/embassy-executor/src/raw/run_queue.rs index 362157535..a88174a0c 100644 --- a/embassy-executor/src/raw/run_queue.rs +++ b/embassy-executor/src/raw/run_queue.rs @@ -2,7 +2,6 @@ use core::ptr; use core::ptr::NonNull; use atomic_polyfill::{AtomicPtr, Ordering}; -use critical_section::CriticalSection; use super::{TaskHeader, TaskRef}; @@ -46,11 +45,18 @@ impl RunQueue { /// /// `item` must NOT be already enqueued in any queue. #[inline(always)] - pub(crate) unsafe fn enqueue(&self, _cs: CriticalSection, task: TaskRef) -> bool { - let prev = self.head.load(Ordering::Relaxed); - task.header().run_queue_item.next.store(prev, Ordering::Relaxed); - self.head.store(task.as_ptr() as _, Ordering::Relaxed); - prev.is_null() + pub(crate) unsafe fn enqueue(&self, task: TaskRef) -> bool { + let mut was_empty = false; + + self.head + .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |prev| { + was_empty = prev.is_null(); + task.header().run_queue_item.next.store(prev, Ordering::Relaxed); + Some(task.as_ptr() as *mut _) + }) + .ok(); + + was_empty } /// Empty the queue, then call `on_task` for each task that was in the queue. -- cgit