Cleanup: remove dead assignment

[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 491ab029dfee11b986b1b218c7b566d9a7b929a1..4277372afdd2e874e5fc643568eb0720f6b51018 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -831,6 +831,7 @@ static int close_metadata(uint64_t chan_key)
 {
        int ret = 0;
        struct lttng_consumer_channel *channel;
+       unsigned int channel_monitor;
 
        DBG("UST consumer close metadata key %" PRIu64, chan_key);
 
@@ -849,13 +850,48 @@ static int close_metadata(uint64_t chan_key)
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
-
+       channel_monitor = channel->monitor;
        if (cds_lfht_is_node_deleted(&channel->node.node)) {
                goto error_unlock;
        }
 
        lttng_ustconsumer_close_metadata(channel);
+       pthread_mutex_unlock(&channel->lock);
+       pthread_mutex_unlock(&consumer_data.lock);
 
+       /*
+        * The ownership of a metadata channel depends on the type of
+        * session to which it belongs. In effect, the monitor flag is checked
+        * to determine if this metadata channel is in "snapshot" mode or not.
+        *
+        * In the non-snapshot case, the metadata channel is created along with
+        * a single stream which will remain present until the metadata channel
+        * is destroyed (on the destruction of its session). In this case, the
+        * metadata stream in "monitored" by the metadata poll thread and holds
+        * the ownership of its channel.
+        *
+        * Closing the metadata will cause the metadata stream's "metadata poll
+        * pipe" to be closed. Closing this pipe will wake-up the metadata poll
+        * thread which will teardown the metadata stream which, in return,
+        * deletes the metadata channel.
+        *
+        * In the snapshot case, the metadata stream is created and destroyed
+        * on every snapshot record. Since the channel doesn't have an owner
+        * other than the session daemon, it is safe to destroy it immediately
+        * on reception of the CLOSE_METADATA command.
+        */
+       if (!channel_monitor) {
+               /*
+                * The channel and consumer_data locks must be
+                * released before this call since consumer_del_channel
+                * re-acquires the channel and consumer_data locks to teardown
+                * the channel and queue its reclamation by the "call_rcu"
+                * worker thread.
+                */
+               consumer_del_channel(channel);
+       }
+
+       return ret;
 error_unlock:
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
@@ -1332,7 +1368,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
        {
                /* Session daemon status message are handled in the following call. */
-               ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
+               consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
                                msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
                                &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
                                msg.u.relayd_sock.relayd_session_id);
@@ -2819,7 +2855,7 @@ int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
        request.key = channel->key;
 
        DBG("Sending metadata request to sessiond, session id %" PRIu64
-                       ", per-pid %" PRIu64 ", app UID %u and channek key %" PRIu64,
+                       ", per-pid %" PRIu64 ", app UID %u and channel key %" PRIu64,
                        request.session_id, request.session_id_per_pid, request.uid,
                        request.key);