diff --git a/libcontainer/container_linux.go b/libcontainer/container_linux.go
index e2f64fcb9..ee08c17e5 100644
--- a/libcontainer/container_linux.go
+++ b/libcontainer/container_linux.go
@@ -853,7 +853,7 @@ func (c *linuxContainer) criuSupportsExtNS(t configs.NamespaceType) bool {
 	return c.checkCriuVersion(minVersion) == nil
 }
 
-func (c *linuxContainer) criuNsToKey(t configs.NamespaceType) string {
+func criuNsToKey(t configs.NamespaceType) string {
 	return "extRoot" + strings.Title(configs.NsName(t)) + "NS"
 }
 
@@ -873,7 +873,7 @@ func (c *linuxContainer) handleCheckpointingExternalNamespaces(rpcOpts *criurpc.
 	if err := unix.Stat(nsPath, &ns); err != nil {
 		return err
 	}
-	criuExternal := fmt.Sprintf("%s[%d]:%s", configs.NsName(t), ns.Ino, c.criuNsToKey(t))
+	criuExternal := fmt.Sprintf("%s[%d]:%s", configs.NsName(t), ns.Ino, criuNsToKey(t))
 	rpcOpts.External = append(rpcOpts.External, criuExternal)
 
 	return nil
@@ -897,11 +897,12 @@ func (c *linuxContainer) handleRestoringExternalNamespaces(rpcOpts *criurpc.Criu
 		logrus.Errorf("If a specific network namespace is defined it must exist: %s", err)
 		return fmt.Errorf("Requested network namespace %v does not exist", nsPath)
 	}
-	inheritFd := new(criurpc.InheritFd)
-	inheritFd.Key = proto.String(c.criuNsToKey(t))
-	// The offset of four is necessary because 0, 1, 2 and 3 is already
-	// used by stdin, stdout, stderr, 'criu swrk' socket.
-	inheritFd.Fd = proto.Int32(int32(4 + len(*extraFiles)))
+	inheritFd := &criurpc.InheritFd{
+		Key: proto.String(criuNsToKey(t)),
+		// The offset of four is necessary because 0, 1, 2 and 3 are
+		// already used by stdin, stdout, stderr, 'criu swrk' socket.
+		Fd: proto.Int32(int32(4 + len(*extraFiles))),
+	}
 	rpcOpts.InheritFd = append(rpcOpts.InheritFd, inheritFd)
 	// All open FDs need to be transferred to CRIU via extraFiles
 	*extraFiles = append(*extraFiles, nsFd)