address comments

Signed-off-by: Ryan Leung <rleungx@gmail.com>

pkg/utils/grpcutil/grpcutil.go

@@ -252,10 +252,7 @@ func CheckStream(ctx context.Context, cancel context.CancelFunc, done chan struc
 
 // NeedRebuildConnection checks if the error is a connection error.
 func NeedRebuildConnection(err error) bool {
-	if err == nil {
-		return false
-	}
-	return err == io.EOF ||
+	return err != nil && err == io.EOF ||
 		strings.Contains(err.Error(), codes.Unavailable.String()) || // Unavailable indicates the service is currently unavailable. This is a most likely a transient condition.
 		strings.Contains(err.Error(), codes.DeadlineExceeded.String()) || // DeadlineExceeded means operation expired before completion.
 		strings.Contains(err.Error(), codes.Internal.String()) || // Internal errors.

server/forward.go

@@ -159,7 +159,7 @@ func (s *GrpcServer) forwardTSO(stream pdpb.PD_TsoServer) error {
 		tsopbResp, err := s.forwardTSORequestWithDeadLine(forwardCtx, cancelForward, forwardStream, request, tsDeadlineCh)
 		if err != nil {
 			tsoStreamErr = errors.WithStack(err)
-			return errors.WithStack(err)
+			return tsoStreamErr
 		}
 
 		// The error types defined for tsopb and pdpb are different, so we need to convert them.