+/*
+ * Initializes the ioengine configured for a job, if it has not been done so
+ * already.
+ */
+int ioengine_load(struct thread_data *td)
+{
+ const char *engine;
+
+ /*
+ * Engine has already been loaded.
+ */
+ if (td->io_ops)
+ return 0;
+
+ engine = get_engine_name(td->o.ioengine);
+ td->io_ops = load_ioengine(td, engine);
+ if (!td->io_ops) {
+ log_err("fio: failed to load engine %s\n", engine);
+ return 1;
+ }
+
+ if (td->io_ops->option_struct_size && td->io_ops->options) {
+ /*
+ * In cases where td->eo is set, clone it for a child thread.
+ * This requires that the parent thread has the same ioengine,
+ * but that requirement must be enforced by the code which
+ * cloned the thread.
+ */
+ void *origeo = td->eo;
+ /*
+ * Otherwise use the default thread options.
+ */
+ if (!origeo && td != &def_thread && def_thread.eo &&
+ def_thread.io_ops->options == td->io_ops->options)
+ origeo = def_thread.eo;
+
+ options_init(td->io_ops->options);
+ td->eo = malloc(td->io_ops->option_struct_size);
+ /*
+ * Use the default thread as an option template if this uses the
+ * same options structure and there are non-default options
+ * used.
+ */
+ if (origeo) {
+ memcpy(td->eo, origeo, td->io_ops->option_struct_size);
+ options_mem_dupe(td->eo, td->io_ops->options);
+ } else {
+ memset(td->eo, 0, td->io_ops->option_struct_size);
+ fill_default_options(td->eo, td->io_ops->options);
+ }
+ *(struct thread_data **)td->eo = td;
+ }
+
+ return 0;
+}
+