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 *);
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 25d3b02..46d81b5 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -568,7 +568,7 @@
 		trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \
 }									\
 									\
-static int ftrace_raw_reg_event_##call(void)				\
+static int ftrace_raw_reg_event_##call(void *ptr)			\
 {									\
 	int ret;							\
 									\
@@ -579,7 +579,7 @@
 	return ret;							\
 }									\
 									\
-static void ftrace_raw_unreg_event_##call(void)				\
+static void ftrace_raw_unreg_event_##call(void *ptr)			\
 {									\
 	unregister_trace_##call(ftrace_raw_event_##call);		\
 }									\
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f95f847..1d289e2 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -86,14 +86,14 @@
 		if (call->enabled) {
 			call->enabled = 0;
 			tracing_stop_cmdline_record();
-			call->unregfunc();
+			call->unregfunc(call->data);
 		}
 		break;
 	case 1:
 		if (!call->enabled) {
 			call->enabled = 1;
 			tracing_start_cmdline_record();
-			call->regfunc();
+			call->regfunc(call->data);
 		}
 		break;
 	}