Commit f5f6b255 authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (VMware)
Browse files

tracing: Add synth_event_delete() 

create_or_delete_synth_event() contains code to delete a synthetic
event, which would be useful on its own - specifically, it would be
useful to allow event-creating modules to call it separately.

Separate out the delete code from that function and create an exported
function named synth_event_delete().

Link: http://lkml.kernel.org/r/050db3b06df7f0a4b8a2922da602d1d879c7c1c2.1580323897.git.zanussi@kernel.org



Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarTom Zanussi <zanussi@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent e3e2a2cc

include/linux/trace_events.h

+2 −0
Original line number Diff line number Diff line
@@ -354,6 +354,8 @@ extern struct trace_event_file *trace_get_event_file(const char *instance, 
						     const char *event);

extern void trace_put_event_file(struct trace_event_file *file);



extern int synth_event_delete(const char *name);



/*

 * Event file flags:

 *  ENABLED	  - The event is enabled

kernel/trace/trace_events_hist.c

+41 −16
Original line number Diff line number Diff line
@@ -1360,29 +1360,54 @@ static int __create_synth_event(int argc, const char *name, const char **argv) 
	goto out;

}



static int create_or_delete_synth_event(int argc, char **argv)

static int destroy_synth_event(struct synth_event *se)

{

	const char *name = argv[0];

	struct synth_event *event = NULL;

	int ret;



	/* trace_run_command() ensures argc != 0 */

	if (name[0] == '!') {

		mutex_lock(&event_mutex);

		event = find_synth_event(name + 1);

		if (event) {

			if (event->ref)

	if (se->ref)

		ret = -EBUSY;

	else {

				ret = unregister_synth_event(event);

		ret = unregister_synth_event(se);

		if (!ret) {

					dyn_event_remove(&event->devent);

					free_synth_event(event);

			dyn_event_remove(&se->devent);

			free_synth_event(se);

		}

	}

		} else

			ret = -ENOENT;



	return ret;

}



/**

 * synth_event_delete - Delete a synthetic event

 * @event_name: The name of the new sythetic event

 *

 * Delete a synthetic event that was created with synth_event_create().

 *

 * Return: 0 if successful, error otherwise.

 */

int synth_event_delete(const char *event_name)

{

	struct synth_event *se = NULL;

	int ret = -ENOENT;



	mutex_lock(&event_mutex);

	se = find_synth_event(event_name);

	if (se)

		ret = destroy_synth_event(se);

	mutex_unlock(&event_mutex);



	return ret;

}

EXPORT_SYMBOL_GPL(synth_event_delete);



static int create_or_delete_synth_event(int argc, char **argv)

{

	const char *name = argv[0];

	int ret;



	/* trace_run_command() ensures argc != 0 */

	if (name[0] == '!') {

		ret = synth_event_delete(name + 1);

		return ret;

	}

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