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Commit faacb361 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
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tracing: Simplify creation and deletion of synthetic events 

Since the event_mutex and synth_event_mutex ordering issue
is gone, we can skip existing event check when adding or
deleting events, and some redundant code in error path.

This changes release_all_synth_events() to abort the process
when it hits any error and returns the error code. It succeeds
only if it has no error.

Link: http://lkml.kernel.org/r/154140847194.17322.17960275728005067803.stgit@devbox



Reviewed-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent fc800a10

kernel/trace/trace_events_hist.c

+18 −35
Original line number Diff line number Diff line
@@ -1008,18 +1008,6 @@ struct hist_var_data { 
	struct hist_trigger_data *hist_data;

};



static void add_or_delete_synth_event(struct synth_event *event, int delete)

{

	if (delete)

		free_synth_event(event);

	else {

		if (!find_synth_event(event->name))

			list_add(&event->list, &synth_event_list);

		else

			free_synth_event(event);

	}

}



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

{

	struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
@@ -1052,14 +1040,15 @@ static int create_synth_event(int argc, char **argv) 
	if (event) {

		if (delete_event) {

			if (event->ref) {

				event = NULL;

				ret = -EBUSY;

				goto out;

			}

			ret = unregister_synth_event(event);

			if (!ret) {

				list_del(&event->list);

			goto out;

				free_synth_event(event);

			}

		event = NULL;

		} else

			ret = -EEXIST;

		goto out;

	} else if (delete_event) {
@@ -1100,29 +1089,21 @@ static int create_synth_event(int argc, char **argv) 
		event = NULL;

		goto err;

	}

 out:

	if (event) {

		if (delete_event) {

			ret = unregister_synth_event(event);

			add_or_delete_synth_event(event, !ret);

		} else {

	ret = register_synth_event(event);

			add_or_delete_synth_event(event, ret);

		}

	}

	if (!ret)

		list_add(&event->list, &synth_event_list);

	else

		free_synth_event(event);

 out:

	mutex_unlock(&synth_event_mutex);

	mutex_unlock(&event_mutex);



	return ret;

 err:

	mutex_unlock(&synth_event_mutex);

	mutex_unlock(&event_mutex);



	for (i = 0; i < n_fields; i++)

		free_synth_field(fields[i]);

	free_synth_event(event);



	return ret;

	goto out;

}



static int release_all_synth_events(void)
@@ -1141,10 +1122,12 @@ static int release_all_synth_events(void) 
	}



	list_for_each_entry_safe(event, e, &synth_event_list, list) {

		list_del(&event->list);



		ret = unregister_synth_event(event);

		add_or_delete_synth_event(event, !ret);

		if (!ret) {

			list_del(&event->list);

			free_synth_event(event);

		} else

			break;

	}

	mutex_unlock(&synth_event_mutex);

	mutex_unlock(&event_mutex);