f manually cas-loop

Author: TheBlueMatt

lightning/src/chain/chainmonitor.rs

@@ -261,7 +261,14 @@ where C::Target: chain::Filter,
 	{
 		let mut dependent_txdata = Vec::new();
 		if let Some(height) = best_height {
-			self.highest_chain_height.fetch_max(height as usize, Ordering::AcqRel);
+			// Sadly AtomicUsize::fetch_max wasn't stabilized until 1.45, so until then we have to
+			// manually CAS.
+			let mut old_height = self.highest_chain_height.fetch(Ordering::Relaxed);
+			while self.highest_chain_height
+				.compare_exchange(old_height, height as usize, Ordering::AcqRel, Ordering::Relaxed).is_err()
+			{
+				old_height = self.highest_chain_height.fetch(Ordering::Acquire);
+			}
 		}
 		{
 			let monitor_states = self.monitors.write().unwrap();