tracing: Update cond flag when enabling or disabling a trigger

When a trigger is enabled, the cond flag should be set beforehand,
otherwise a trigger that's expecting to process a trace record
(e.g. one with post_trigger set) could be invoked without one.

Likewise a trigger's cond flag should be reset after it's disabled,
not before.

Link: http://lkml.kernel.org/r/a420b52a67b1c2d3cab017914362d153255acb99.1448303214.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_events_trigger.c

@@ -543,11 +543,12 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
 	list_add_rcu(&data->list, &file->triggers);
 	ret++;
 
+	update_cond_flag(file);
 	if (trace_event_trigger_enable_disable(file, 1) < 0) {
 		list_del_rcu(&data->list);
+		update_cond_flag(file);
 		ret--;
 	}
-	update_cond_flag(file);
 out:
 	return ret;
 }
@@ -575,8 +576,8 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 		if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 			unregistered = true;
 			list_del_rcu(&data->list);
-			update_cond_flag(file);
 			trace_event_trigger_enable_disable(file, 0);
+			update_cond_flag(file);
 			break;
 		}
 	}
@@ -1319,11 +1320,12 @@ static int event_enable_register_trigger(char *glob,
 	list_add_rcu(&data->list, &file->triggers);
 	ret++;
 
+	update_cond_flag(file);
 	if (trace_event_trigger_enable_disable(file, 1) < 0) {
 		list_del_rcu(&data->list);
+		update_cond_flag(file);
 		ret--;
 	}
-	update_cond_flag(file);
 out:
 	return ret;
 }
@@ -1344,8 +1346,8 @@ static void event_enable_unregister_trigger(char *glob,
 		    (enable_data->file == test_enable_data->file)) {
 			unregistered = true;
 			list_del_rcu(&data->list);
-			update_cond_flag(file);
 			trace_event_trigger_enable_disable(file, 0);
+			update_cond_flag(file);
 			break;
 		}
 	}