[FAB-17289] Fix gossip goroutine leak when reading msg (hyperledger#439)

Signed-off-by: Shitaibin <hz_stb@163.com>
Change-Id: I52acd1631b996ac44cd76a2f6c1319ae3a18cfb3

gossip/comm/conn.go

@@ -217,7 +217,7 @@ func newConnection(cl proto.GossipClient, c *grpc.ClientConn, cs proto.Gossip_Go
 		clientStream: cs,
 		serverStream: ss,
 		stopFlag:     int32(0),
-		stopChan:     make(chan struct{}, 1),
+		stopChan:     make(chan struct{}),
 		recvBuffSize: config.RecvBuffSize,
 	}
 	return connection
@@ -257,7 +257,7 @@ func (conn *connection) close() {
 		return
 	}
 
-	conn.stopChan <- struct{}{}
+	close(conn.stopChan)
 
 	conn.drainOutputBuffer()
 	conn.Lock()
@@ -306,21 +306,18 @@ func (conn *connection) send(msg *proto.SignedGossipMessage, onErr func(error),
 func (conn *connection) serviceConnection() error {
 	errChan := make(chan error, 1)
 	msgChan := make(chan *proto.SignedGossipMessage, conn.recvBuffSize)
-	quit := make(chan struct{})
 	// Call stream.Recv() asynchronously in readFromStream(),
 	// and wait for either the Recv() call to end,
 	// or a signal to close the connection, which exits
 	// the method and makes the Recv() call to fail in the
 	// readFromStream() method
-	go conn.readFromStream(errChan, quit, msgChan)
+	go conn.readFromStream(errChan, msgChan)
 
 	go conn.writeToStream()
 
 	for !conn.toDie() {
 		select {
-		case stop := <-conn.stopChan:
-			conn.logger.Debug("Closing reading from stream")
-			conn.stopChan <- stop
+		case <-conn.stopChan:
 			return nil
 		case err := <-errChan:
 			return err
@@ -346,9 +343,8 @@ func (conn *connection) writeToStream() {
 				return
 			}
 			conn.metrics.SentMessages.Add(1)
-		case stop := <-conn.stopChan:
+		case <-conn.stopChan:
 			conn.logger.Debug("Closing writing to stream")
-			conn.stopChan <- stop
 			return
 		}
 	}
@@ -366,7 +362,7 @@ func (conn *connection) drainOutputBuffer() {
 	}
 }
 
-func (conn *connection) readFromStream(errChan chan error, quit chan struct{}, msgChan chan *proto.SignedGossipMessage) {
+func (conn *connection) readFromStream(errChan chan error, msgChan chan *proto.SignedGossipMessage) {
 	for !conn.toDie() {
 		stream := conn.getStream()
 		if stream == nil {
@@ -392,7 +388,8 @@ func (conn *connection) readFromStream(errChan chan error, quit chan struct{}, m
 		}
 		select {
 		case msgChan <- msg:
-		case <-quit:
+		case <-conn.stopChan:
+			conn.logger.Debug("Closing reading from stream")
 			return
 		}
 	}