Fix: relayd metadata size

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

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 974c65f550c94a6be3fb94c18227f86ad133076e..831592a1e96ef4a8a22b64fdc29ffeaa75f62786 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -261,16 +261,17 @@ void consumer_del_stream(struct lttng_consumer_stream *stream)
        }
 
        /* Check and cleanup relayd */
+       rcu_read_lock();
        relayd = consumer_find_relayd(stream->net_seq_idx);
        if (relayd != NULL) {
-               /* We are about to modify the relayd refcount */
-               rcu_read_lock();
-               if (!--relayd->refcount) {
+               uatomic_dec(&relayd->refcount);
+               assert(uatomic_read(&relayd->refcount) >= 0);
+               if (uatomic_read(&relayd->refcount) == 0) {
                        /* Refcount of the relayd struct is 0, destroy it */
                        consumer_destroy_relayd(relayd);
                }
-               rcu_read_unlock();
        }
+       rcu_read_unlock();
 
        if (!--stream->chan->refcount) {
                free_chan = stream->chan;
@@ -371,8 +372,8 @@ int consumer_add_stream(struct lttng_consumer_stream *stream)
        pthread_mutex_lock(&consumer_data.lock);
        /* Steal stream identifier, for UST */
        consumer_steal_stream_key(stream->key);
-       rcu_read_lock();
 
+       rcu_read_lock();
        lttng_ht_lookup(consumer_data.stream_ht,
                        (void *)((unsigned long) stream->key), &iter);
        node = lttng_ht_iter_get_node_ulong(&iter);
@@ -383,16 +384,13 @@ int consumer_add_stream(struct lttng_consumer_stream *stream)
        }
 
        lttng_ht_add_unique_ulong(consumer_data.stream_ht, &stream->node);
-       rcu_read_unlock();
 
        /* Check and cleanup relayd */
        relayd = consumer_find_relayd(stream->net_seq_idx);
        if (relayd != NULL) {
-               /* We are about to modify the relayd refcount */
-               rcu_read_lock();
-               relayd->refcount++;
-               rcu_read_unlock();
+               uatomic_inc(&relayd->refcount);
        }
+       rcu_read_unlock();
 
        /* Update consumer data */
        consumer_data.stream_count++;
@@ -482,6 +480,8 @@ error:
  * Find a relayd socket pair in the global consumer data.
  *
  * Return the object if found else NULL.
+ * RCU read-side lock must be held across this call and while using the
+ * returned object.
  */
 struct consumer_relayd_sock_pair *consumer_find_relayd(int key)
 {
@@ -494,8 +494,6 @@ struct consumer_relayd_sock_pair *consumer_find_relayd(int key)
                goto error;
        }
 
-       rcu_read_lock();
-
        lttng_ht_lookup(consumer_data.relayd_ht, (void *)((unsigned long) key),
                        &iter);
        node = lttng_ht_iter_get_node_ulong(&iter);
@@ -503,8 +501,6 @@ struct consumer_relayd_sock_pair *consumer_find_relayd(int key)
                relayd = caa_container_of(node, struct consumer_relayd_sock_pair, node);
        }
 
-       rcu_read_unlock();
-
 error:
        return relayd;
 }
@@ -528,6 +524,7 @@ int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
        /* Reset data header */
        memset(&data_hdr, 0, sizeof(data_hdr));
 
+       rcu_read_lock();
        /* Get relayd reference of the stream. */
        relayd = consumer_find_relayd(stream->net_seq_idx);
        if (relayd == NULL) {
@@ -562,6 +559,7 @@ int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
        }
 
 error:
+       rcu_read_unlock();
        return outfd;
 }