return;
}
+/*
+ * We need to execute ht_destroy outside of RCU read-side critical
+ * section, so we postpone its execution using call_rcu. It is simpler
+ * than to change the semantic of the many callers of
+ * destroy_channel().
+ */
+static
+void destroy_channel_rcu(struct rcu_head *head)
+{
+ struct ust_registry_channel *chan =
+ caa_container_of(head, struct ust_registry_channel, rcu_head);
+
+ if (chan->ht) {
+ lttng_ht_destroy(chan->ht);
+ }
+ free(chan);
+}
+
/*
* Destroy every element of the registry and free the memory. This does NOT
* free the registry pointer since it might not have been allocated before so
* it's the caller responsability.
- *
- * This *MUST NOT* be called within a RCU read side lock section.
*/
static void destroy_channel(struct ust_registry_channel *chan)
{
ust_registry_destroy_event(chan, event);
}
rcu_read_unlock();
-
- lttng_ht_destroy(chan->ht);
- free(chan);
+ call_rcu(&chan->rcu_head, destroy_channel_rcu);
}
/*
if (!chan) {
PERROR("zmalloc ust registry channel");
ret = -ENOMEM;
- goto error;
+ goto error_alloc;
}
chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
lttng_ht_add_unique_u64(session->channels, &chan->node);
rcu_read_unlock();
+ return 0;
+
error:
+ destroy_channel(chan);
+error_alloc:
return ret;
}
ret = lttng_ht_del(session->channels, &iter);
assert(!ret);
rcu_read_unlock();
-
- /*
- * Destroying the hash table should be done without RCU
- * read-side lock held. Since we own "chan" now, it is OK to use
- * it outside of RCU read-side critical section.
- */
destroy_channel(chan);
end:
session = zmalloc(sizeof(*session));
if (!session) {
PERROR("zmalloc ust registry session");
- goto error;
+ goto error_alloc;
}
pthread_mutex_init(&session->lock, NULL);
return 0;
error:
+ ust_registry_session_destroy(session);
+error_alloc:
return -1;
}
assert(!ret);
destroy_channel(chan);
}
- lttng_ht_destroy(reg->channels);
rcu_read_unlock();
+ if (reg->channels) {
+ lttng_ht_destroy(reg->channels);
+ }
free(reg->metadata);
}