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Replace deprecated compare_and_swap with compare_exchange #2297

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Merged
merged 1 commit into from
Dec 25, 2020
Merged

Replace deprecated compare_and_swap with compare_exchange #2297

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42 changes: 20 additions & 22 deletions futures-channel/src/mpsc/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -923,17 +923,16 @@ impl<T> Clone for UnboundedSenderInner<T> {
debug_assert!(curr < MAX_BUFFER);

let next = curr + 1;
let actual = self.inner.num_senders.compare_and_swap(curr, next, SeqCst);

// The ABA problem doesn't matter here. We only care that the
// number of senders never exceeds the maximum.
if actual == curr {
return Self {
inner: self.inner.clone(),
};
match self.inner.num_senders.compare_exchange(curr, next, SeqCst, SeqCst) {
Ok(_) => {
// The ABA problem doesn't matter here. We only care that the
// number of senders never exceeds the maximum.
return Self {
inner: self.inner.clone(),
};
}
Err(actual) => curr = actual,
}

curr = actual;
}
}
}
Expand All @@ -954,19 +953,18 @@ impl<T> Clone for BoundedSenderInner<T> {
debug_assert!(curr < self.inner.max_senders());

let next = curr + 1;
let actual = self.inner.num_senders.compare_and_swap(curr, next, SeqCst);

// The ABA problem doesn't matter here. We only care that the
// number of senders never exceeds the maximum.
if actual == curr {
return Self {
inner: self.inner.clone(),
sender_task: Arc::new(Mutex::new(SenderTask::new())),
maybe_parked: false,
};
match self.inner.num_senders.compare_exchange(curr, next, SeqCst, SeqCst) {
Ok(_) => {
// The ABA problem doesn't matter here. We only care that the
// number of senders never exceeds the maximum.
return Self {
inner: self.inner.clone(),
sender_task: Arc::new(Mutex::new(SenderTask::new())),
maybe_parked: false,
};
}
Err(actual) => curr = actual,
}

curr = actual;
}
}
}
Expand Down
6 changes: 5 additions & 1 deletion futures-core/src/task/__internal/atomic_waker.rs
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Expand Up @@ -259,7 +259,11 @@ impl AtomicWaker {
/// }
/// ```
pub fn register(&self, waker: &Waker) {
match self.state.compare_and_swap(WAITING, REGISTERING, Acquire) {
match self
.state
.compare_exchange(WAITING, REGISTERING, Acquire, Acquire)
.unwrap_or_else(|x| x)
{
WAITING => {
unsafe {
// Locked acquired, update the waker cell
Expand Down
27 changes: 18 additions & 9 deletions futures-util/src/future/future/shared.rs
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Expand Up @@ -210,7 +210,12 @@ where

inner.record_waker(&mut this.waker_key, cx);

match inner.notifier.state.compare_and_swap(IDLE, POLLING, SeqCst) {
match inner
.notifier
.state
.compare_exchange(IDLE, POLLING, SeqCst, SeqCst)
.unwrap_or_else(|x| x)
{
IDLE => {
// Lock acquired, fall through
}
Expand Down Expand Up @@ -255,14 +260,18 @@ where

match future.poll(&mut cx) {
Poll::Pending => {
match inner.notifier.state.compare_and_swap(POLLING, IDLE, SeqCst) {
POLLING => {
// Success
drop(_reset);
this.inner = Some(inner);
return Poll::Pending;
}
_ => unreachable!(),
if inner
.notifier
.state
.compare_exchange(POLLING, IDLE, SeqCst, SeqCst)
.is_ok()
{
// Success
drop(_reset);
this.inner = Some(inner);
return Poll::Pending;
} else {
unreachable!()
}
}
Poll::Ready(output) => output,
Expand Down