Split LockableScore responsibilities between read & write operations

    - Split Score from LockableScore to ScoreLookUp to handle read
      operations and ScoreUpdate to handle write operations
    - Change all struct that implemented Score to implement ScoreLookUp
      and/or ScoreUpdate
    - Change Mutex's to RwLocks to allow multiple data readers
    - Change LockableScore to Deref in ScorerAccountingForInFlightHtlcs
      as we only need to read
    - Add ScoreLookUp and ScoreUpdate docs
    - Remove reference(&'a) and Sized from Score in ScorerAccountingForInFlightHtlcs
      as Score implements Deref
    - Split MultiThreadedScoreLock into MultiThreadedScoreLockWrite and MultiThreadedScoreLockRead.
      After splitting LockableScore, we split MultiThreadedScoreLock following
      the same way, splitting a single score into two srtucts, one for read and
      other for write.
      MultiThreadedScoreLock is used in c_bindings.

Author: jbesraa

lightning-background-processor/src/lib.rs

@@ -34,7 +34,7 @@ use lightning::ln::peer_handler::APeerManager;
 use lightning::routing::gossip::{NetworkGraph, P2PGossipSync};
 use lightning::routing::utxo::UtxoLookup;
 use lightning::routing::router::Router;
-use lightning::routing::scoring::{Score, WriteableScore};
+use lightning::routing::scoring::{ScoreUpdate, WriteableScore};
 use lightning::util::logger::Logger;
 use lightning::util::persist::Persister;
 #[cfg(feature = "std")]
@@ -241,23 +241,27 @@ fn handle_network_graph_update<L: Deref>(
 fn update_scorer<'a, S: 'static + Deref<Target = SC> + Send + Sync, SC: 'a + WriteableScore<'a>>(
 	scorer: &'a S, event: &Event
 ) -> bool {
-	let mut score = scorer.lock();
 	match event {
 		Event::PaymentPathFailed { ref path, short_channel_id: Some(scid), .. } => {
+			let mut score = scorer.write_lock();
 			score.payment_path_failed(path, *scid);
 		},
 		Event::PaymentPathFailed { ref path, payment_failed_permanently: true, .. } => {
 			// Reached if the destination explicitly failed it back. We treat this as a successful probe
 			// because the payment made it all the way to the destination with sufficient liquidity.
+			let mut score = scorer.write_lock();
 			score.probe_successful(path);
 		},
 		Event::PaymentPathSuccessful { path, .. } => {
+			let mut score = scorer.write_lock();
 			score.payment_path_successful(path);
 		},
 		Event::ProbeSuccessful { path, .. } => {
+			let mut score = scorer.write_lock();
 			score.probe_successful(path);
 		},
 		Event::ProbeFailed { path, short_channel_id: Some(scid), .. } => {
+			let mut score = scorer.write_lock();
 			score.probe_failed(path, *scid);
 		},
 		_ => return false,
@@ -858,7 +862,7 @@ mod tests {
 	use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor, IgnoringMessageHandler};
 	use lightning::routing::gossip::{NetworkGraph, NodeId, P2PGossipSync};
 	use lightning::routing::router::{DefaultRouter, Path, RouteHop};
-	use lightning::routing::scoring::{ChannelUsage, Score};
+	use lightning::routing::scoring::{ChannelUsage, ScoreUpdate, ScoreLookUp};
 	use lightning::util::config::UserConfig;
 	use lightning::util::ser::Writeable;
 	use lightning::util::test_utils;
@@ -1033,12 +1037,14 @@ mod tests {
 		fn write<W: lightning::util::ser::Writer>(&self, _: &mut W) -> Result<(), lightning::io::Error> { Ok(()) }
 	}
 
-	impl Score for TestScorer {
+	impl ScoreLookUp for TestScorer {
 		type ScoreParams = ();
 		fn channel_penalty_msat(
 			&self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId, _usage: ChannelUsage, _score_params: &Self::ScoreParams
 		) -> u64 { unimplemented!(); }
+	}
 
+	impl ScoreUpdate for TestScorer {
 		fn payment_path_failed(&mut self, actual_path: &Path, actual_short_channel_id: u64) {
 			if let Some(expectations) = &mut self.event_expectations {
 				match expectations.pop_front().unwrap() {

lightning/src/ln/channelmanager.rs

@@ -10582,7 +10582,7 @@ pub mod bench {
 	use bitcoin::hashes::sha256::Hash as Sha256;
 	use bitcoin::{Block, BlockHeader, PackedLockTime, Transaction, TxMerkleNode, TxOut};
 
-	use crate::sync::{Arc, Mutex};
+	use crate::sync::{Arc, Mutex, RwLock};
 
 	use criterion::Criterion;
 
@@ -10619,7 +10619,7 @@ pub mod bench {
 		let tx_broadcaster = test_utils::TestBroadcaster::new(network);
 		let fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: Mutex::new(253) };
 		let logger_a = test_utils::TestLogger::with_id("node a".to_owned());
-		let scorer = Mutex::new(test_utils::TestScorer::new());
+		let scorer = RwLock::new(test_utils::TestScorer::new());
 		let router = test_utils::TestRouter::new(Arc::new(NetworkGraph::new(network, &logger_a)), &scorer);
 
 		let mut config: UserConfig = Default::default();

lightning/src/ln/functional_test_utils.rs

@@ -43,7 +43,7 @@ use crate::io;
 use crate::prelude::*;
 use core::cell::RefCell;
 use alloc::rc::Rc;
-use crate::sync::{Arc, Mutex, LockTestExt};
+use crate::sync::{Arc, Mutex, LockTestExt, RwLock};
 use core::mem;
 use core::iter::repeat;
 use bitcoin::{PackedLockTime, TxMerkleNode};
@@ -352,7 +352,7 @@ pub struct TestChanMonCfg {
 	pub persister: test_utils::TestPersister,
 	pub logger: test_utils::TestLogger,
 	pub keys_manager: test_utils::TestKeysInterface,
-	pub scorer: Mutex<test_utils::TestScorer>,
+	pub scorer: RwLock<test_utils::TestScorer>,
 }
 
 pub struct NodeCfg<'a> {
@@ -539,7 +539,7 @@ impl<'a, 'b, 'c> Drop for Node<'a, 'b, 'c> {
 					channel_monitors.insert(monitor.get_funding_txo().0, monitor);
 				}
 
-				let scorer = Mutex::new(test_utils::TestScorer::new());
+				let scorer = RwLock::new(test_utils::TestScorer::new());
 				let mut w = test_utils::TestVecWriter(Vec::new());
 				self.node.write(&mut w).unwrap();
 				<(BlockHash, ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>)>::read(&mut io::Cursor::new(w.0), ChannelManagerReadArgs {
@@ -2634,7 +2634,7 @@ pub fn create_chanmon_cfgs(node_count: usize) -> Vec<TestChanMonCfg> {
 		let persister = test_utils::TestPersister::new();
 		let seed = [i as u8; 32];
 		let keys_manager = test_utils::TestKeysInterface::new(&seed, Network::Testnet);
-		let scorer = Mutex::new(test_utils::TestScorer::new());
+		let scorer = RwLock::new(test_utils::TestScorer::new());
 
 		chan_mon_cfgs.push(TestChanMonCfg { tx_broadcaster, fee_estimator, chain_source, logger, persister, keys_manager, scorer });
 	}

lightning/src/ln/functional_tests.rs

@@ -56,7 +56,7 @@ use alloc::collections::BTreeSet;
 use core::default::Default;
 use core::iter::repeat;
 use bitcoin::hashes::Hash;
-use crate::sync::{Arc, Mutex};
+use crate::sync::{Arc, Mutex, RwLock};
 
 use crate::ln::functional_test_utils::*;
 use crate::ln::chan_utils::CommitmentTransaction;
@@ -5434,7 +5434,7 @@ fn test_key_derivation_params() {
 	let keys_manager = test_utils::TestKeysInterface::new(&seed, Network::Testnet);
 	let chain_monitor = test_utils::TestChainMonitor::new(Some(&chanmon_cfgs[0].chain_source), &chanmon_cfgs[0].tx_broadcaster, &chanmon_cfgs[0].logger, &chanmon_cfgs[0].fee_estimator, &chanmon_cfgs[0].persister, &keys_manager);
 	let network_graph = Arc::new(NetworkGraph::new(Network::Testnet, &chanmon_cfgs[0].logger));
-	let scorer = Mutex::new(test_utils::TestScorer::new());
+	let scorer = RwLock::new(test_utils::TestScorer::new());
 	let router = test_utils::TestRouter::new(network_graph.clone(), &scorer);
 	let node = NodeCfg { chain_source: &chanmon_cfgs[0].chain_source, logger: &chanmon_cfgs[0].logger, tx_broadcaster: &chanmon_cfgs[0].tx_broadcaster, fee_estimator: &chanmon_cfgs[0].fee_estimator, router, chain_monitor, keys_manager: &keys_manager, network_graph, node_seed: seed, override_init_features: alloc::rc::Rc::new(core::cell::RefCell::new(None)) };
 	let mut node_cfgs = create_node_cfgs(3, &chanmon_cfgs);

lightning/src/ln/outbound_payment.rs

@@ -1516,7 +1516,7 @@ mod tests {
 	use crate::ln::outbound_payment::{OutboundPayments, Retry, RetryableSendFailure};
 	use crate::routing::gossip::NetworkGraph;
 	use crate::routing::router::{InFlightHtlcs, Path, PaymentParameters, Route, RouteHop, RouteParameters};
-	use crate::sync::{Arc, Mutex};
+	use crate::sync::{Arc, Mutex, RwLock};
 	use crate::util::errors::APIError;
 	use crate::util::test_utils;
 
@@ -1555,7 +1555,7 @@ mod tests {
 		let outbound_payments = OutboundPayments::new();
 		let logger = test_utils::TestLogger::new();
 		let network_graph = Arc::new(NetworkGraph::new(Network::Testnet, &logger));
-		let scorer = Mutex::new(test_utils::TestScorer::new());
+		let scorer = RwLock::new(test_utils::TestScorer::new());
 		let router = test_utils::TestRouter::new(network_graph, &scorer);
 		let secp_ctx = Secp256k1::new();
 		let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
@@ -1602,7 +1602,7 @@ mod tests {
 		let outbound_payments = OutboundPayments::new();
 		let logger = test_utils::TestLogger::new();
 		let network_graph = Arc::new(NetworkGraph::new(Network::Testnet, &logger));
-		let scorer = Mutex::new(test_utils::TestScorer::new());
+		let scorer = RwLock::new(test_utils::TestScorer::new());
 		let router = test_utils::TestRouter::new(network_graph, &scorer);
 		let secp_ctx = Secp256k1::new();
 		let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
@@ -1644,7 +1644,7 @@ mod tests {
 		let outbound_payments = OutboundPayments::new();
 		let logger = test_utils::TestLogger::new();
 		let network_graph = Arc::new(NetworkGraph::new(Network::Testnet, &logger));
-		let scorer = Mutex::new(test_utils::TestScorer::new());
+		let scorer = RwLock::new(test_utils::TestScorer::new());
 		let router = test_utils::TestRouter::new(network_graph, &scorer);
 		let secp_ctx = Secp256k1::new();
 		let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);

lightning/src/ln/payment_tests.rs

@@ -2544,7 +2544,7 @@ fn retry_multi_path_single_failed_payment() {
 		}, Ok(route.clone()));
 
 	{
-		let scorer = chanmon_cfgs[0].scorer.lock().unwrap();
+		let scorer = chanmon_cfgs[0].scorer.read().unwrap();
 		// The initial send attempt, 2 paths
 		scorer.expect_usage(chans[0].short_channel_id.unwrap(), ChannelUsage { amount_msat: 10_000, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown });
 		scorer.expect_usage(chans[1].short_channel_id.unwrap(), ChannelUsage { amount_msat: 100_000_001, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown });