ftrace: add compile-time check on F_printk()

Make sure F_printk() has corrent format and args, and make sure
changes in F_STRUCT() won't break F_printk().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AADF6CC.1060809@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_export.c

@@ -22,6 +22,47 @@
 #undef __field_struct
 #define __field_struct(type, item)
 
+#undef __field
+#define __field(type, item)				type item;
+
+#undef __field_desc
+#define __field_desc(type, container, item)		type item;
+
+#undef __array
+#define __array(type, item, size)			type item[size];
+
+#undef __array_desc
+#define __array_desc(type, container, item, size)	type item[size];
+
+#undef __dynamic_array
+#define __dynamic_array(type, item)			type item[];
+
+#undef F_STRUCT
+#define F_STRUCT(args...)				args
+
+#undef F_printk
+#define F_printk(fmt, args...) fmt, args
+
+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(name, struct_name, id, tstruct, print)	\
+struct ____ftrace_##name {					\
+	tstruct							\
+};								\
+static void __used ____ftrace_check_##name(void)		\
+{								\
+	struct ____ftrace_##name *__entry = NULL;		\
+								\
+	/* force cmpile-time check on F_printk() */		\
+	printk(print);						\
+}
+
+#undef FTRACE_ENTRY_DUP
+#define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print)	\
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
+#include "trace_entries.h"
+
+
 #undef __field
 #define __field(type, item)						\
 	ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t"	\
@@ -88,10 +129,6 @@ ftrace_format_##name(struct ftrace_event_call *unused,			\
 	return ret;							\
 }
 
-#undef FTRACE_ENTRY_DUP
-#define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print)	\
-	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
-
 #include "trace_entries.h"