trace/simple: add st_init_group

Add helper function and call it for each trace event group added.
Makes sure that events added at module load time are initialized
properly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20210601132414.432430-6-kraxel@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

trace/control.c

@@ -82,6 +82,10 @@ void trace_event_register_group(TraceEvent **events)
     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
     event_groups[nevent_groups].events = events;
     nevent_groups++;
+
+#ifdef CONFIG_TRACE_SIMPLE
+    st_init_group(nevent_groups - 1);
+#endif
 }
 
 

trace/simple.c

@@ -422,3 +422,15 @@ bool st_init(void)
     atexit(st_flush_trace_buffer);
     return true;
 }
+
+void st_init_group(size_t group)
+{
+    TraceEventIter iter;
+
+    if (!trace_writeout_enabled) {
+        return;
+    }
+
+    trace_event_iter_init_group(&iter, group);
+    st_write_event_mapping(&iter);
+}

trace/simple.h

@@ -15,6 +15,7 @@ void st_print_trace_file_status(void);
 bool st_set_trace_file_enabled(bool enable);
 void st_set_trace_file(const char *file);
 bool st_init(void);
+void st_init_group(size_t group);
 void st_flush_trace_buffer(void);
 
 typedef struct {