Index: kernel/generic/include/ipc/ipc.h
===================================================================
--- kernel/generic/include/ipc/ipc.h	(revision 5378f99e2f33edd586f039d1bdcabfd690939a29)
+++ kernel/generic/include/ipc/ipc.h	(revision 56273bba63681b1fbd77cac08c9ee56c7e06507f)
@@ -115,4 +115,10 @@
  */
 #define IPC_FF_ROUTE_FROM_ME  (1 << 0)
+
+/* Data transfer flags. */
+#define IPC_XF_NONE		0
+
+/** Restrict the transfer size if necessary. */
+#define IPC_XF_RESTRICT		(1 << 0)
 
 /** Kernel IPC interfaces