store/tikv: remove use of MatchStoreLabels transaction option in store/tikv

store/driver/txn/snapshot.go

@@ -17,6 +17,7 @@ import (
 	"context"
 	"unsafe"
 
+	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/store/tikv"
 	tikvstore "github.com/pingcap/tidb/store/tikv/kv"
@@ -73,6 +74,8 @@ func (s *tikvSnapshot) SetOption(opt int, val interface{}) {
 		s.KVSnapshot.SetNotFillCache(val.(bool))
 	case tikvstore.SnapshotTS:
 		s.KVSnapshot.SetSnapshotTS(val.(uint64))
+	case tikvstore.MatchStoreLabels:
+		s.KVSnapshot.SetMatchStoreLabels(val.([]*metapb.StoreLabel))
 	default:
 		s.KVSnapshot.SetOption(opt, val)
 	}

store/driver/txn/txn_driver.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/opentracing/opentracing-go"
 	"github.com/pingcap/errors"
+	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/sessionctx/binloginfo"
@@ -152,6 +153,8 @@ func (txn *tikvTxn) SetOption(opt int, val interface{}) {
 		txn.SetEnable1PC(val.(bool))
 	case tikvstore.TxnScope:
 		txn.SetScope(val.(string))
+	case tikvstore.MatchStoreLabels:
+		txn.KVTxn.GetSnapshot().SetMatchStoreLabels(val.([]*metapb.StoreLabel))
 	default:
 		txn.KVTxn.SetOption(opt, val)
 	}

store/tikv/snapshot.go

@@ -583,10 +583,6 @@ func (s *KVSnapshot) SetOption(opt int, val interface{}) {
 		s.mu.Lock()
 		s.mu.isStaleness = val.(bool)
 		s.mu.Unlock()
-	case kv.MatchStoreLabels:
-		s.mu.Lock()
-		s.mu.matchStoreLabels = val.([]*metapb.StoreLabel)
-		s.mu.Unlock()
 	}
 }
 
@@ -625,6 +621,13 @@ func (s *KVSnapshot) SetPriority(pri Priority) {
 	s.priority = pri
 }
 
+// SetMatchStoreLabels sets up labels to filter target stores.
+func (s *KVSnapshot) SetMatchStoreLabels(labels []*metapb.StoreLabel) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.mu.matchStoreLabels = labels
+}
+
 // SnapCacheHitCount gets the snapshot cache hit count. Only for test.
 func (s *KVSnapshot) SnapCacheHitCount() int {
 	return int(atomic.LoadInt64(&s.mu.hitCnt))