+
+int register_stat_tracer(struct tracer_stat *trace)
+{
+ struct stat_session *session, *node;
+ int ret;
+
+ if (!trace)
+ return -EINVAL;
+
+ if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
+ return -EINVAL;
+
+ /* Already registered? */
+ mutex_lock(&all_stat_sessions_mutex);
+ list_for_each_entry(node, &all_stat_sessions, session_list) {
+ if (node->ts == trace) {
+ mutex_unlock(&all_stat_sessions_mutex);
+ return -EINVAL;
+ }
+ }
+ mutex_unlock(&all_stat_sessions_mutex);
+
+ /* Init the session */
+ session = kzalloc(sizeof(*session), GFP_KERNEL);
+ if (!session)
+ return -ENOMEM;
+
+ session->ts = trace;
+ INIT_LIST_HEAD(&session->session_list);
+ mutex_init(&session->stat_mutex);
+
+ ret = init_stat_file(session);
+ if (ret) {
+ destroy_session(session);
+ return ret;
+ }
+
+ /* Register */
+ mutex_lock(&all_stat_sessions_mutex);
+ list_add_tail(&session->session_list, &all_stat_sessions);
+ mutex_unlock(&all_stat_sessions_mutex);
+
+ return 0;
+}
+
+void unregister_stat_tracer(struct tracer_stat *trace)
+{
+ struct stat_session *node, *tmp;
+
+ mutex_lock(&all_stat_sessions_mutex);
+ list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
+ if (node->ts == trace) {
+ list_del(&node->session_list);
+ destroy_session(node);
+ break;
+ }
+ }
+ mutex_unlock(&all_stat_sessions_mutex);
+}