+static void wng_pre_select(struct sched *s, struct task *t)
+{
+ struct writer_node_group *g = container_of(t, struct writer_node_group, task);
+ int i;
+
+ FOR_EACH_WRITER_NODE(i, g) {
+ struct writer_node *wn = &g->writer_nodes[i];
+ struct writer *w = writers + wn->writer_num;
+ if (!w->pre_select)
+ continue;
+ t->error = w->pre_select(s, wn);
+ if (t->error < 0)
+ return;
+ }
+ /*
+ * Force a minimal delay if something was written during the previous
+ * call to wng_post_select(). This is necessary because the filter
+ * chain might still have data for us which it couldn't convert during
+ * the previous run due to its buffer size constraints. In this case we
+ * do not want to wait until the next input data arrives as this could
+ * lead to buffer underruns.
+ */
+ if (g->last_written == 0)
+ return;
+ s->timeout.tv_sec = 0;
+ s->timeout.tv_usec = 1;
+}
+
+static void wng_post_select(struct sched *s, struct task *t)