+
+/*
+ * Clear a kernel session.
+ *
+ * Return LTTNG_OK on success or else an LTTng error code.
+ */
+enum lttng_error_code kernel_clear_session(struct ltt_session *session)
+{
+ int ret;
+ enum lttng_error_code status = LTTNG_OK;
+ struct consumer_socket *socket;
+ struct lttng_ht_iter iter;
+ struct ltt_kernel_session *ksess = session->kernel_session;
+
+ assert(ksess);
+ assert(ksess->consumer);
+
+ DBG("Cleat kernel session %s (session %" PRIu64 ")",
+ session->name, session->id);
+
+ rcu_read_lock();
+
+ /*
+ * Note that this loop will end after one iteration given that there is
+ * only one kernel consumer.
+ */
+ cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
+ socket, node.node) {
+ struct ltt_kernel_channel *chan;
+
+ /* For each channel, ask the consumer to clear it. */
+ cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
+ DBG("Clear kernel channel %" PRIu64 ", session %s",
+ chan->key, session->name);
+ ret = consumer_clear_channel(socket, chan->key,
+ ksess->consumer);
+ if (ret < 0) {
+ goto error;
+ }
+ }
+
+ /*
+ * Clear the metadata channel.
+ * Metadata channel is not cleared per se but we still need to
+ * perform rotation operation on it behind the scene.
+ */
+ ret = consumer_clear_channel(socket, ksess->metadata->key,
+ ksess->consumer);
+ if (ret < 0) {
+ goto error;
+ }
+ }
+
+ goto end;
+error:
+ switch (-ret) {
+ case LTTCOMM_CONSUMERD_RELAYD_DISALLOW_CLEAR:
+ status = LTTNG_ERR_CLEAR_RELAY_DISALLOW;
+ break;
+ default:
+ status = LTTNG_ERR_CLEAR_FAIL_CONSUMER;
+ break;
+ }
+end:
+ rcu_read_unlock();
+ return status;
+}