tracing: Add ftrace_event_call void * 'data' field

add an optional void * pointer to 'ftrace_event_call' that is
passed in for regfunc and unregfunc.

This prepares for syscall tracepoints creation by passing the name of
the syscall we want to trace and then retrieve its number through our
arch syscall table.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index ac8c6f8..8544f12 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -112,8 +112,8 @@
 	struct dentry		*dir;
 	struct trace_event	*event;
 	int			enabled;
-	int			(*regfunc)(void);
-	void			(*unregfunc)(void);
+	int			(*regfunc)(void *);
+	void			(*unregfunc)(void *);
 	int			id;
 	int			(*raw_init)(void);
 	int			(*show_format)(struct trace_seq *s);
@@ -122,6 +122,7 @@
 	int			filter_active;
 	struct event_filter	*filter;
 	void			*mod;
+	void			*data;
 
 	atomic_t		profile_count;
 	int			(*profile_enable)(struct ftrace_event_call *);