Use Acq/Rel ordering everywhere #17
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Also fix docs
yvt
reviewed
Oct 9, 2021
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Looks good, but they are unnecessarily strong in many places. They are are harmless by themselves but can conceal synchronization bugs in user code.
Another possible option is to keep the ordering parameters but enforce a minimum ordering like atomic_ref 0.2.1.
| @@ -244,7 +235,7 @@ where | |||
| P: IntoRawPtr + FromRawPtr, | |||
| { | |||
| fn drop(&mut self) { | |||
| self.take(Ordering::Relaxed); | |||
| self.take(); | |||
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This can use the Relaxed ordering or even a non-atomic access (*self.inner.get_mut())
| pub fn compare_and_swap( | ||
| &self, | ||
| current: Option<&P>, | ||
| new: Option<P>, | ||
| order: Ordering, | ||
| ) -> Result<Option<P>, (Option<P>, *mut P)> { |
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Unrelated to the change, but isn't this *mut P actually *mut <P as Deref>::Target? At least this is true for the IntoRawPtr implementations provided by this crate.
| ) -> Result<Option<P>, (Option<P>, *mut P)> { | ||
| let pnew = Self::inner_into_raw(new); | ||
| self.inner | ||
| .compare_exchange(Self::inner_as_ptr(current), pnew, success, failure) | ||
| .compare_exchange(Self::inner_as_ptr(current), pnew, Ordering::AcqRel, Ordering::Acquire) |
| ) -> Result<Option<P>, (Option<P>, *mut P)> { | ||
| let pnew = Self::inner_into_raw(new); | ||
| self.inner | ||
| .compare_exchange_weak(Self::inner_as_ptr(current), pnew, success, failure) | ||
| .compare_exchange_weak(Self::inner_as_ptr(current), pnew, Ordering::AcqRel, Ordering::Acquire) |
Apply suggestions from code review Co-authored-by: yvt <[email protected]>
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Fixes #15
Changed all methods to use
Acquire,ReleaseorAcqRel, whichever is the strictest.I had to remove the ordering parameters from all the methods, so it's a breaking change.