Implement lib counter

[lttng-modules.git] / src / lttng-events.c

diff --git a/src/lttng-events.c b/src/lttng-events.c
index 75a193045b1d381a3bf531542e763d741b095d8a..012f2245a353f4b7c43c689985b30628d65063d1 100644 (file)
--- a/src/lttng-events.c
+++ b/src/lttng-events.c
@@ -52,6 +52,7 @@
 static LIST_HEAD(sessions);
 static LIST_HEAD(event_notifier_groups);
 static LIST_HEAD(lttng_transport_list);
+static LIST_HEAD(lttng_counter_transport_list);
 /*
  * Protect the sessions and metadata caches.
  */
@@ -759,6 +760,18 @@ void _lttng_metadata_channel_hangup(struct lttng_metadata_stream *stream)
        wake_up_interruptible(&stream->read_wait);
 }
 
+static
+struct lttng_counter_transport *lttng_counter_transport_find(const char *name)
+{
+       struct lttng_counter_transport *transport;
+
+       list_for_each_entry(transport, &lttng_counter_transport_list, node) {
+               if (!strcmp(transport->name, name))
+                       return transport;
+       }
+       return NULL;
+}
+
 /*
  * Supports event creation while tracing session is active.
  * Needs to be called with sessions mutex held.
@@ -3878,6 +3891,29 @@ void lttng_transport_unregister(struct lttng_transport *transport)
 }
 EXPORT_SYMBOL_GPL(lttng_transport_unregister);
 
+void lttng_counter_transport_register(struct lttng_counter_transport *transport)
+{
+       /*
+        * Make sure no page fault can be triggered by the module about to be
+        * registered. We deal with this here so we don't have to call
+        * vmalloc_sync_mappings() in each module's init.
+        */
+       wrapper_vmalloc_sync_mappings();
+
+       mutex_lock(&sessions_mutex);
+       list_add_tail(&transport->node, &lttng_counter_transport_list);
+       mutex_unlock(&sessions_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_counter_transport_register);
+
+void lttng_counter_transport_unregister(struct lttng_counter_transport *transport)
+{
+       mutex_lock(&sessions_mutex);
+       list_del(&transport->node);
+       mutex_unlock(&sessions_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_counter_transport_unregister);
+
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
 
 enum cpuhp_state lttng_hp_prepare;