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Subject[PATCH 1/2 v3] tracepoints: Remove unnecessary "data_args" macro parameter
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

While working on a clean up that would restructure the difference between
architectures that have static calls vs those that do not, I was stumbling
over the "data_args" parameter that includes "__data" in the arguments. The
issue was that one version didn't even need it, while the other one did.
Instead of injecting a "__data = NULL;" into the macro for the unneeded
version, just remove it completely.

The original idea behind data_args is that there may be a case of a
tracepoint with no arguments. But this is considered bad practice, and all
tracepoints should pass something to that location (that's what tracepoints
were created for).

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
include/linux/tracepoint.h | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 966ed8980327..42bb5b753b33 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -160,13 +160,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
/*
* it_func[0] is never NULL because there is at least one element in the array
* when the array itself is non NULL.
- *
- * Note, the proto and args passed in includes "__data" as the first parameter.
- * The reason for this is to handle the "void" prototype. If a tracepoint
- * has a "void" prototype, then it is invalid to declare a function
- * as "(void *, void)".
*/
-#define __DO_TRACE(name, proto, args, cond, rcuidle) \
+#define __DO_TRACE(name, args, cond, rcuidle) \
do { \
struct tracepoint_func *it_func_ptr; \
int __maybe_unused __idx = 0; \
@@ -194,7 +189,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
rcu_dereference_raw((&__tracepoint_##name)->funcs); \
if (it_func_ptr) { \
__data = (it_func_ptr)->data; \
- __DO_TRACE_CALL(name)(args); \
+ __DO_TRACE_CALL(name)(__data, args); \
} \
\
if (rcuidle) { \
@@ -206,17 +201,16 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
} while (0)

#ifndef MODULE
-#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \
+#define __DECLARE_TRACE_RCU(name, proto, args, cond) \
static inline void trace_##name##_rcuidle(proto) \
{ \
if (static_key_false(&__tracepoint_##name.key)) \
__DO_TRACE(name, \
- TP_PROTO(data_proto), \
- TP_ARGS(data_args), \
+ TP_ARGS(args), \
TP_CONDITION(cond), 1); \
}
#else
-#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
+#define __DECLARE_TRACE_RCU(name, proto, args, cond)
#endif

/*
@@ -231,7 +225,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
* even when this tracepoint is off. This code has no purpose other than
* poking RCU a bit.
*/
-#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
+#define __DECLARE_TRACE(name, proto, args, cond, data_proto) \
extern int __traceiter_##name(data_proto); \
DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \
extern struct tracepoint __tracepoint_##name; \
@@ -239,8 +233,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
{ \
if (static_key_false(&__tracepoint_##name.key)) \
__DO_TRACE(name, \
- TP_PROTO(data_proto), \
- TP_ARGS(data_args), \
+ TP_ARGS(args), \
TP_CONDITION(cond), 0); \
if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \
rcu_read_lock_sched_notrace(); \
@@ -249,7 +242,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
} \
} \
__DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \
- PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \
+ PARAMS(cond)) \
static inline int \
register_trace_##name(void (*probe)(data_proto), void *data) \
{ \
@@ -332,7 +325,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)


#else /* !TRACEPOINTS_ENABLED */
-#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
+#define __DECLARE_TRACE(name, proto, args, cond, data_proto) \
static inline void trace_##name(proto) \
{ } \
static inline void trace_##name##_rcuidle(proto) \
@@ -412,14 +405,12 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
#define DECLARE_TRACE(name, proto, args) \
__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
cpu_online(raw_smp_processor_id()), \
- PARAMS(void *__data, proto), \
- PARAMS(__data, args))
+ PARAMS(void *__data, proto))

#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
- PARAMS(void *__data, proto), \
- PARAMS(__data, args))
+ PARAMS(void *__data, proto))

#define TRACE_EVENT_FLAGS(event, flag)

--
2.29.2

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