op-batcher: remove unecessary mutex (#13569)

* Revert "op-batcher: Fix concurrent map write (#13527)"

This reverts commit 90435d07.

* lock channelMgrMutex during recordFailedDARequest

* rename / export pruneSafeBlocks and pruneChannels

op-batcher/batcher/channel_manager.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"sync"
 
 	"github.com/ethereum-optimism/optimism/op-batcher/metrics"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
@@ -56,8 +55,6 @@ type channelManager struct {
 	channelQueue []*channel
 	// used to lookup channels by tx ID upon tx success / failure
 	txChannels map[string]*channel
-
-	mtx sync.Mutex
 }
 
 func NewChannelManager(log log.Logger, metr metrics.Metricer, cfgProvider ChannelConfigProvider, rollupCfg *rollup.Config) *channelManager {
@@ -96,9 +93,6 @@ func (s *channelManager) pendingBlocks() int {
 // TxFailed records a transaction as failed. It will attempt to resubmit the data
 // in the failed transaction.
 func (s *channelManager) TxFailed(_id txID) {
-	s.mtx.Lock()
-	defer s.mtx.Unlock()
-
 	id := _id.String()
 	if channel, ok := s.txChannels[id]; ok {
 		delete(s.txChannels, id)
@@ -111,8 +105,6 @@ func (s *channelManager) TxFailed(_id txID) {
 // TxConfirmed marks a transaction as confirmed on L1. Only if the channel timed out
 // the channelManager's state is modified.
 func (s *channelManager) TxConfirmed(_id txID, inclusionBlock eth.BlockID) {
-	s.mtx.Lock()
-	defer s.mtx.Unlock()
 
 	id := _id.String()
 	if channel, ok := s.txChannels[id]; ok {
@@ -199,9 +191,6 @@ func (s *channelManager) nextTxData(channel *channel) (txData, error) {
 // When switching DA type, the channelManager state will be rebuilt
 // with a new ChannelConfig.
 func (s *channelManager) TxData(l1Head eth.BlockID) (txData, error) {
-	s.mtx.Lock()
-	defer s.mtx.Unlock()
-
 	channel, err := s.getReadyChannel(l1Head)
 	if err != nil {
 		return emptyTxData, err
@@ -463,8 +452,8 @@ func l2BlockRefFromBlockAndL1Info(block *types.Block, l1info *derive.L1BlockInfo
 
 var ErrPendingAfterClose = errors.New("pending channels remain after closing channel-manager")
 
-// pruneSafeBlocks dequeues the provided number of blocks from the internal blocks queue
-func (s *channelManager) pruneSafeBlocks(num int) {
+// PruneSafeBlocks dequeues the provided number of blocks from the internal blocks queue
+func (s *channelManager) PruneSafeBlocks(num int) {
 	_, ok := s.blocks.DequeueN(int(num))
 	if !ok {
 		panic("tried to prune more blocks than available")
@@ -475,8 +464,8 @@ func (s *channelManager) pruneSafeBlocks(num int) {
 	}
 }
 
-// pruneChannels dequeues the provided number of channels from the internal channels queue
-func (s *channelManager) pruneChannels(num int) {
+// PruneChannels dequeues the provided number of channels from the internal channels queue
+func (s *channelManager) PruneChannels(num int) {
 	clearCurrentChannel := false
 	for i := 0; i < num; i++ {
 		if s.channelQueue[i] == s.currentChannel {

op-batcher/batcher/channel_manager_test.go

@@ -550,10 +550,10 @@ func TestChannelManager_PruneBlocks(t *testing.T) {
 			m.blocks = tc.initialQ
 			m.blockCursor = tc.initialBlockCursor
 			if tc.expectedQ != nil {
-				m.pruneSafeBlocks(tc.numChannelsToPrune)
+				m.PruneSafeBlocks(tc.numChannelsToPrune)
 				require.Equal(t, tc.expectedQ, m.blocks)
 			} else {
-				require.Panics(t, func() { m.pruneSafeBlocks(tc.numChannelsToPrune) })
+				require.Panics(t, func() { m.PruneSafeBlocks(tc.numChannelsToPrune) })
 			}
 		})
 	}
@@ -618,11 +618,11 @@ func TestChannelManager_PruneChannels(t *testing.T) {
 			m.channelQueue = tc.initialQ
 			m.currentChannel = tc.initialCurrentChannel
 			if tc.expectedQ != nil {
-				m.pruneChannels(tc.numChannelsToPrune)
+				m.PruneChannels(tc.numChannelsToPrune)
 				require.Equal(t, tc.expectedQ, m.channelQueue)
 				require.Equal(t, tc.expectedCurrentChannel, m.currentChannel)
 			} else {
-				require.Panics(t, func() { m.pruneChannels(tc.numChannelsToPrune) })
+				require.Panics(t, func() { m.PruneChannels(tc.numChannelsToPrune) })
 			}
 		})
 	}

op-batcher/batcher/driver.go

@@ -413,8 +413,8 @@ func (l *BatchSubmitter) syncAndPrune(syncStatus *eth.SyncStatus) *inclusiveBloc
 	if syncActions.clearState != nil {
 		l.channelMgr.Clear(*syncActions.clearState)
 	} else {
-		l.channelMgr.pruneSafeBlocks(syncActions.blocksToPrune)
-		l.channelMgr.pruneChannels(syncActions.channelsToPrune)
+		l.channelMgr.PruneSafeBlocks(syncActions.blocksToPrune)
+		l.channelMgr.PruneChannels(syncActions.channelsToPrune)
 	}
 	return syncActions.blocksToLoad
 }
@@ -892,6 +892,8 @@ func (l *BatchSubmitter) handleReceipt(r txmgr.TxReceipt[txRef]) {
 }
 
 func (l *BatchSubmitter) recordFailedDARequest(id txID, err error) {
+	l.channelMgrMutex.Lock()
+	defer l.channelMgrMutex.Unlock()
 	if err != nil {
 		l.Log.Warn("DA request failed", logFields(id, err)...)
 	}