eth: accept transactions when starting CPU mining (#13882)

eth/backend.go

@@ -22,6 +22,7 @@ import (
 	"math/big"
 	"regexp"
 	"sync"
+	"sync/atomic"
 
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
@@ -326,12 +327,19 @@ func (self *Ethereum) SetEtherbase(etherbase common.Address) {
 	self.miner.SetEtherbase(etherbase)
 }
 
-func (s *Ethereum) StartMining() error {
+func (s *Ethereum) StartMining(local bool) error {
 	eb, err := s.Etherbase()
 	if err != nil {
 		log.Error("Cannot start mining without etherbase", "err", err)
 		return fmt.Errorf("etherbase missing: %v", err)
 	}
+	if local {
+		// If local (CPU) mining is started, we can disable the transaction rejection
+		// mechanism introduced to speed sync times. CPU mining on mainnet is ludicrous
+		// so noone will ever hit this path, whereas marking sync done on CPU mining
+		// will ensure that private networks work in single miner mode too.
+		atomic.StoreUint32(&s.protocolManager.acceptTxs, 1)
+	}
 	go s.miner.Start(eb)
 	return nil
 }