tracing: introduce TRACE_EVENT_NOP()
Sometimes we want to define a tracepoint as a do-nothing function.
So I introduce TRACE_EVENT_NOP, DECLARE_EVENT_CLASS_NOP and
DEFINE_EVENT_NOP for this kind of usage.
Link: http://lkml.kernel.org/r/1553602391-11926-2-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 9c31865..86b019a 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -548,4 +548,19 @@
#define TRACE_EVENT_PERF_PERM(event, expr...)
+#define DECLARE_EVENT_NOP(name, proto, args) \
+ static inline void trace_##name(proto) \
+ { } \
+ static inline bool trace_##name##_enabled(void) \
+ { \
+ return false; \
+ }
+
+#define TRACE_EVENT_NOP(name, proto, args, struct, assign, print) \
+ DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
+
+#define DECLARE_EVENT_CLASS_NOP(name, proto, args, tstruct, assign, print)
+#define DEFINE_EVENT_NOP(template, name, proto, args) \
+ DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
+
#endif /* ifdef TRACE_EVENT (see note above) */