Improve locking on batch transaction submission to better handler concurrent requests

Author: m-Peter

services/requester/batch_tx_pool.go

@@ -124,6 +124,9 @@ func (t *BatchTxPool) Add(
 		return err
 	}
 
+	t.txMux.Lock()
+	defer t.txMux.Unlock()
+
 	eoaActivity, found := t.eoaActivityCache.Get(from)
 	nonce := tx.Nonce()
 
@@ -162,13 +165,11 @@ func (t *BatchTxPool) Add(
 		// If the EOA has pooled transactions, which are not yet processed,
 		// due to congestion or anything, make sure to include the current
 		// tx on that batch.
-		t.txMux.Lock()
 		hasBatch := len(t.pooledTxs[from]) > 0
 		if hasBatch {
 			userTx := pooledEvmTx{txPayload: hexEncodedTx, nonce: nonce}
 			t.pooledTxs[from] = append(t.pooledTxs[from], userTx)
 		}
-		t.txMux.Unlock()
 
 		// If it wasn't batched, submit individually
 		if !hasBatch {
@@ -177,10 +178,8 @@ func (t *BatchTxPool) Add(
 		}
 	} else {
 		// Case 3. EOA activity found AND it was less than [X] seconds ago:
-		t.txMux.Lock()
 		userTx := pooledEvmTx{txPayload: hexEncodedTx, nonce: nonce}
 		t.pooledTxs[from] = append(t.pooledTxs[from], userTx)
-		t.txMux.Unlock()
 	}
 
 	if err != nil {
@@ -319,9 +318,6 @@ func (t *BatchTxPool) updateEOAActivityMetadata(
 	from gethCommon.Address,
 	nonce uint64,
 ) {
-	t.txMux.Lock()
-	defer t.txMux.Unlock()
-
 	// Update metadata for the last EOA activity only on successful add/submit.
 	eoaActivity, _ := t.eoaActivityCache.Get(from)
 	eoaActivity.lastSubmission = time.Now()