Index: uspace/lib/c/include/ipc/common.h
===================================================================
--- uspace/lib/c/include/ipc/common.h	(revision c4c60250a236ed30397cd89ce5cea5eaf59cfba5)
+++ uspace/lib/c/include/ipc/common.h	(revision 7c0e1f596a64720b6f6a6ec66b3499a9d26511cb)
@@ -43,8 +43,11 @@
 #define IPC_FLAG_BLOCKING  0x01
 
+struct async_call;
+
 typedef struct {
 	sysarg_t args[IPC_CALL_LEN];
 	task_id_t in_task_id;
 	sysarg_t in_phone_hash;
+	struct async_call *label;
 } ipc_call_t;
 
Index: uspace/lib/c/include/ipc/ipc.h
===================================================================
--- uspace/lib/c/include/ipc/ipc.h	(revision c4c60250a236ed30397cd89ce5cea5eaf59cfba5)
+++ uspace/lib/c/include/ipc/ipc.h	(revision 7c0e1f596a64720b6f6a6ec66b3499a9d26511cb)
@@ -89,19 +89,18 @@
 
 #define ipc_call_async_0(phoneid, method, private, callback) \
-	ipc_call_async_fast((phoneid), (method), 0, 0, 0, 0, (private), \
-	    (callback))
+	ipc_call_async_fast((phoneid), (method), 0, 0, 0, (private), (callback))
 #define ipc_call_async_1(phoneid, method, arg1, private, callback) \
-	ipc_call_async_fast((phoneid), (method), (arg1), 0, 0, 0, (private), \
+	ipc_call_async_fast((phoneid), (method), (arg1), 0, 0, (private), \
 	    (callback))
 #define ipc_call_async_2(phoneid, method, arg1, arg2, private, callback) \
-	ipc_call_async_fast((phoneid), (method), (arg1), (arg2), 0, 0, \
+	ipc_call_async_fast((phoneid), (method), (arg1), (arg2), 0, \
 	    (private), (callback))
 #define ipc_call_async_3(phoneid, method, arg1, arg2, arg3, private, callback) \
-	ipc_call_async_fast((phoneid), (method), (arg1), (arg2), (arg3), 0, \
+	ipc_call_async_fast((phoneid), (method), (arg1), (arg2), (arg3), \
 	    (private), (callback))
 #define ipc_call_async_4(phoneid, method, arg1, arg2, arg3, arg4, private, \
     callback) \
-	ipc_call_async_fast((phoneid), (method), (arg1), (arg2), (arg3), \
-	    (arg4), (private), (callback))
+	ipc_call_async_slow((phoneid), (method), (arg1), (arg2), (arg3), \
+	    (arg4), 0, (private), (callback))
 #define ipc_call_async_5(phoneid, method, arg1, arg2, arg3, arg4, arg5, \
     private, callback) \
@@ -110,5 +109,5 @@
 
 extern void ipc_call_async_fast(int, sysarg_t, sysarg_t, sysarg_t, sysarg_t,
-    sysarg_t, void *, ipc_async_callback_t);
+    void *, ipc_async_callback_t);
 extern void ipc_call_async_slow(int, sysarg_t, sysarg_t, sysarg_t, sysarg_t,
     sysarg_t, sysarg_t, void *, ipc_async_callback_t);