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Commit a1d0ce82 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
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tracing: Use class->reg() for all registering of events 



Because kprobes and syscalls need special processing to register
events, the class->reg() method was created to handle the differences.

But instead of creating a default ->reg for perf and ftrace events,
the code was scattered with:

	if (class->reg)
		class->reg();
	else
		default_reg();

This is messy and can also lead to bugs.

This patch cleans up this code and creates a default reg() entry for
the events allowing for the code to directly call the class->reg()
without the condition.

Reported-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent d62f85d1

include/linux/ftrace_event.h

+3 −0
Original line number Diff line number Diff line
@@ -146,6 +146,9 @@ struct ftrace_event_class { 
	int			(*raw_init)(struct ftrace_event_call *);

};



extern int ftrace_event_reg(struct ftrace_event_call *event,

			    enum trace_reg type);



enum {

	TRACE_EVENT_FL_ENABLED_BIT,

	TRACE_EVENT_FL_FILTERED_BIT,

include/trace/ftrace.h

+2 −0
Original line number Diff line number Diff line
@@ -439,6 +439,7 @@ static inline notrace int ftrace_get_offsets_##call( \ 
 *	.fields			= LIST_HEAD_INIT(event_class_##call.fields),

 *	.raw_init		= trace_event_raw_init,

 *	.probe			= ftrace_raw_event_##call,

 *	.reg			= ftrace_event_reg,

 * };

 *

 * static struct ftrace_event_call __used
@@ -567,6 +568,7 @@ static struct ftrace_event_class __used event_class_##call = { \ 
	.fields			= LIST_HEAD_INIT(event_class_##call.fields),\

	.raw_init		= trace_event_raw_init,			\

	.probe			= ftrace_raw_event_##call,		\

	.reg			= ftrace_event_reg,			\

	_TRACE_PERF_INIT(call)						\

};

kernel/trace/trace_event_perf.c

+3 −16
Original line number Diff line number Diff line
@@ -54,13 +54,7 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event, 
		}

	}



	if (tp_event->class->reg)

	ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER);

	else

		ret = tracepoint_probe_register(tp_event->name,

						tp_event->class->perf_probe,

						tp_event);



	if (ret)

		goto fail;
@@ -94,9 +88,7 @@ int perf_trace_init(struct perf_event *p_event) 
	mutex_lock(&event_mutex);

	list_for_each_entry(tp_event, &ftrace_events, list) {

		if (tp_event->event.type == event_id &&

		    tp_event->class &&

		    (tp_event->class->perf_probe ||

		     tp_event->class->reg) &&

		    tp_event->class && tp_event->class->reg &&

		    try_module_get(tp_event->mod)) {

			ret = perf_trace_event_init(tp_event, p_event);

			break;
@@ -136,12 +128,7 @@ void perf_trace_destroy(struct perf_event *p_event) 
	if (--tp_event->perf_refcount > 0)

		goto out;



	if (tp_event->class->reg)

	tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);

	else

		tracepoint_probe_unregister(tp_event->name,

					    tp_event->class->perf_probe,

					    tp_event);



	/*

	 * Ensure our callback won't be called anymore. See

kernel/trace/trace_events.c

+36 −19
Original line number Diff line number Diff line
@@ -141,6 +141,35 @@ int trace_event_raw_init(struct ftrace_event_call *call) 
}

EXPORT_SYMBOL_GPL(trace_event_raw_init);



int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)

{

	switch (type) {

	case TRACE_REG_REGISTER:

		return tracepoint_probe_register(call->name,

						 call->class->probe,

						 call);

	case TRACE_REG_UNREGISTER:

		tracepoint_probe_unregister(call->name,

					    call->class->probe,

					    call);

		return 0;



#ifdef CONFIG_PERF_EVENTS

	case TRACE_REG_PERF_REGISTER:

		return tracepoint_probe_register(call->name,

						 call->class->perf_probe,

						 call);

	case TRACE_REG_PERF_UNREGISTER:

		tracepoint_probe_unregister(call->name,

					    call->class->perf_probe,

					    call);

		return 0;

#endif

	}

	return 0;

}

EXPORT_SYMBOL_GPL(ftrace_event_reg);



static int ftrace_event_enable_disable(struct ftrace_event_call *call,

					int enable)

{
@@ -151,23 +180,13 @@ static int ftrace_event_enable_disable(struct ftrace_event_call *call, 
		if (call->flags & TRACE_EVENT_FL_ENABLED) {

			call->flags &= ~TRACE_EVENT_FL_ENABLED;

			tracing_stop_cmdline_record();

			if (call->class->reg)

			call->class->reg(call, TRACE_REG_UNREGISTER);

			else

				tracepoint_probe_unregister(call->name,

							    call->class->probe,

							    call);

		}

		break;

	case 1:

		if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {

			tracing_start_cmdline_record();

			if (call->class->reg)

			ret = call->class->reg(call, TRACE_REG_REGISTER);

			else

				ret = tracepoint_probe_register(call->name,

								call->class->probe,

								call);

			if (ret) {

				tracing_stop_cmdline_record();

				pr_info("event trace: Could not enable event "
@@ -205,8 +224,7 @@ static int __ftrace_set_clr_event(const char *match, const char *sub, 
	mutex_lock(&event_mutex);

	list_for_each_entry(call, &ftrace_events, list) {



		if (!call->name || !call->class ||

		    (!call->class->probe && !call->class->reg))

		if (!call->name || !call->class || !call->class->reg)

			continue;



		if (match &&
@@ -332,7 +350,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos) 
		 * The ftrace subsystem is for showing formats only.

		 * They can not be enabled or disabled via the event files.

		 */

		if (call->class && (call->class->probe || call->class->reg))

		if (call->class && call->class->reg)

			return call;

	}
@@ -485,8 +503,7 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 


	mutex_lock(&event_mutex);

	list_for_each_entry(call, &ftrace_events, list) {

		if (!call->name || !call->class ||

		    (!call->class->probe && !call->class->reg))

		if (!call->name || !call->class || !call->class->reg)

			continue;



		if (system && strcmp(call->class->system, system) != 0)
@@ -977,12 +994,12 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, 
		return -1;

	}



	if (call->class->probe || call->class->reg)

	if (call->class->reg)

		trace_create_file("enable", 0644, call->dir, call,

				  enable);



#ifdef CONFIG_PERF_EVENTS

	if (call->event.type && (call->class->perf_probe || call->class->reg))

	if (call->event.type && call->class->reg)

		trace_create_file("id", 0444, call->dir, call,

		 		  id);

#endif