transport: remove some defers (#1538)

transport/transport.go

@@ -67,20 +67,20 @@ func newRecvBuffer() *recvBuffer {
 
 func (b *recvBuffer) put(r recvMsg) {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) == 0 {
 		select {
 		case b.c <- r:
+			b.mu.Unlock()
 			return
 		default:
 		}
 	}
 	b.backlog = append(b.backlog, r)
+	b.mu.Unlock()
 }
 
 func (b *recvBuffer) load() {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) > 0 {
 		select {
 		case b.c <- b.backlog[0]:
@@ -89,6 +89,7 @@ func (b *recvBuffer) load() {
 		default:
 		}
 	}
+	b.mu.Unlock()
 }
 
 // get returns the channel that receives a recvMsg in the buffer.
@@ -164,20 +165,20 @@ func newControlBuffer() *controlBuffer {
 
 func (b *controlBuffer) put(r item) {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) == 0 {
 		select {
 		case b.c <- r:
+			b.mu.Unlock()
 			return
 		default:
 		}
 	}
 	b.backlog = append(b.backlog, r)
+	b.mu.Unlock()
 }
 
 func (b *controlBuffer) load() {
 	b.mu.Lock()
-	defer b.mu.Unlock()
 	if len(b.backlog) > 0 {
 		select {
 		case b.c <- b.backlog[0]:
@@ -186,6 +187,7 @@ func (b *controlBuffer) load() {
 		default:
 		}
 	}
+	b.mu.Unlock()
 }
 
 // get returns the channel that receives an item in the buffer.
@@ -314,8 +316,9 @@ func (s *Stream) Header() (metadata.MD, error) {
 // side only.
 func (s *Stream) Trailer() metadata.MD {
 	s.mu.RLock()
-	defer s.mu.RUnlock()
-	return s.trailer.Copy()
+	c := s.trailer.Copy()
+	s.mu.RUnlock()
+	return c
 }
 
 // ServerTransport returns the underlying ServerTransport for the stream.
@@ -343,14 +346,16 @@ func (s *Stream) Status() *status.Status {
 // Server side only.
 func (s *Stream) SetHeader(md metadata.MD) error {
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	if s.headerOk || s.state == streamDone {
+		s.mu.Unlock()
 		return ErrIllegalHeaderWrite
 	}
 	if md.Len() == 0 {
+		s.mu.Unlock()
 		return nil
 	}
 	s.header = metadata.Join(s.header, md)
+	s.mu.Unlock()
 	return nil
 }
 
@@ -361,8 +366,8 @@ func (s *Stream) SetTrailer(md metadata.MD) error {
 		return nil
 	}
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	s.trailer = metadata.Join(s.trailer, md)
+	s.mu.Unlock()
 	return nil
 }
 
@@ -413,15 +418,17 @@ func (s *Stream) finish(st *status.Status) {
 // BytesSent indicates whether any bytes have been sent on this stream.
 func (s *Stream) BytesSent() bool {
 	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.bytesSent
+	bs := s.bytesSent
+	s.mu.Unlock()
+	return bs
 }
 
 // BytesReceived indicates whether any bytes have been received on this stream.
 func (s *Stream) BytesReceived() bool {
 	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.bytesReceived
+	br := s.bytesReceived
+	s.mu.Unlock()
+	return br
 }
 
 // GoString is implemented by Stream so context.String() won't