Fix if a enqueued instant is first in a non-empty queue

rtic-monotonics/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rtic-monotonics"
-version = "1.0.0-alpha.0"
+version = "1.0.0-alpha.1"
 
 edition = "2021"
 authors = [
@@ -17,7 +17,7 @@ license = "MIT OR Apache-2.0"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rtic-time = { version = "1.0.0-alpha.0", path = "../rtic-time" }
+rtic-time = { version = "1.0.0-alpha.1", path = "../rtic-time" }
 embedded-hal-async = { version = "0.2.0-alpha.0", optional = true }
 fugit = { version = "0.3.6" }
 atomic-polyfill = "1"

rtic-time/CHANGELOG.md

@@ -15,4 +15,6 @@ For each category, *Added*, *Changed*, *Fixed* add new entries at the top!
 
 ### Fixed
 
+- If the queue was non-empty and a new instant was added that was earlier than `head`, then the queue would no pend the monotonic handler. This would cause the new `head` to be dequeued at the wrong time.
+
 ## [v1.0.0] - 2023-xx-xx

rtic-time/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rtic-time"
-version = "1.0.0-alpha.0"
+version = "1.0.0-alpha.1"
 
 edition = "2021"
 authors = [

rtic-time/src/lib.rs

@@ -25,7 +25,7 @@ mod monotonic;
 struct WaitingWaker<Mono: Monotonic> {
     waker: Waker,
     release_at: Mono::Instant,
-    was_poped: AtomicBool,
+    was_popped: AtomicBool,
 }
 
 impl<Mono: Monotonic> Clone for WaitingWaker<Mono> {
@@ -33,7 +33,7 @@ impl<Mono: Monotonic> Clone for WaitingWaker<Mono> {
         Self {
             waker: self.waker.clone(),
             release_at: self.release_at,
-            was_poped: AtomicBool::new(self.was_poped.load(Ordering::Relaxed)),
+            was_popped: AtomicBool::new(self.was_popped.load(Ordering::Relaxed)),
         }
     }
 }
@@ -132,7 +132,7 @@ impl<Mono: Monotonic> TimerQueue<Mono> {
                 release_at = Some(head.release_at);
 
                 let should_pop = Mono::should_dequeue_check(head.release_at);
-                head.was_poped.store(should_pop, Ordering::Relaxed);
+                head.was_popped.store(should_pop, Ordering::Relaxed);
 
                 should_pop
             });
@@ -234,7 +234,7 @@ impl<Mono: Monotonic> TimerQueue<Mono> {
                 let link_ref = link.insert(Link::new(WaitingWaker {
                     waker: cx.waker().clone(),
                     release_at: instant,
-                    was_poped: AtomicBool::new(false),
+                    was_popped: AtomicBool::new(false),
                 }));
 
                 // SAFETY(new_unchecked): The address to the link is stable as it is defined
@@ -243,13 +243,13 @@ impl<Mono: Monotonic> TimerQueue<Mono> {
                 // we make sure in `dropper` that the link is removed from the queue before
                 // dropping `link_ptr` AND `dropper` makes sure that the shadowed `link_ptr` lives
                 // until the end of the stack frame.
-                let (was_empty, addr) = unsafe { queue.insert(Pin::new_unchecked(link_ref)) };
+                let (head_updated, addr) = unsafe { queue.insert(Pin::new_unchecked(link_ref)) };
 
                 marker.store(addr, Ordering::Relaxed);
 
-                if was_empty {
-                    // Pend the monotonic handler if the queue was empty to setup the timer.
-                    Mono::pend_interrupt();
+                if head_updated {
+                    // Pend the monotonic handler if the queue head was updated.
+                    Mono::pend_interrupt()
                 }
             }
 
@@ -261,8 +261,8 @@ impl<Mono: Monotonic> TimerQueue<Mono> {
         // exited the `poll_fn` below in the `drop(dropper)` call. The other dereference
         // of this pointer is in the `poll_fn`.
         if let Some(link) = unsafe { link_ptr.get() } {
-            if link.val.was_poped.load(Ordering::Relaxed) {
-                // If it was poped from the queue there is no need to run delete
+            if link.val.was_popped.load(Ordering::Relaxed) {
+                // If it was popped from the queue there is no need to run delete
                 dropper.defuse();
             }
         } else {

rtic-time/src/linked_list.rs

@@ -92,7 +92,8 @@ impl<T: PartialOrd + Clone> LinkedList<T> {
     }
 
     /// Insert a new link into the linked list.
-    /// The return is (was_empty, address), where the address of the link is for use with `delete`.
+    /// The return is (updated head, address), where the address of the link is for use
+    /// with `delete`.
     ///
     /// SAFETY: The pinned link must live until it is removed from this list.
     pub unsafe fn insert(&self, val: Pin<&Link<T>>) -> (bool, usize) {
@@ -127,7 +128,7 @@ impl<T: PartialOrd + Clone> LinkedList<T> {
                 self.head
                     .store(val as *const _ as *mut _, Ordering::Relaxed);
 
-                return (false, addr);
+                return (true, addr);
             }
 
             // 3. search list for correct place

rtic/Cargo.toml

@@ -22,7 +22,7 @@ name = "rtic"
 readme = "../README.md"
 repository = "https://github.com/rtic-rs/rtic"
 
-version = "2.0.0-alpha.0"
+version = "2.0.0-alpha.1"
 
 [lib]
 name = "rtic"
@@ -32,7 +32,7 @@ cortex-m = { version = "0.7.0", optional = true }
 bare-metal = "1.0.0"
 #portable-atomic = { version = "0.3.19" }
 atomic-polyfill = "1"
-rtic-monotonics = { path = "../rtic-monotonics", version = "1.0.0-alpha.0", optional = true }
+rtic-monotonics = { path = "../rtic-monotonics", version = "1.0.0-alpha.1", optional = true }
 rtic-macros = { path = "../rtic-macros", version = "2.0.0-alpha.0" }
 rtic-core = "1"
 critical-section = "1"