+
+/*
+ * This job is sent to the kevent workqueue.
+ * While no event is once sent to any callback, the connector workqueue
+ * is not created to avoid a useless waiting kernel task.
+ * Once the first event is received, we create this dedicated workqueue which
+ * is necessary because the flow of data can be high and we don't want
+ * to encumber keventd with that.
+ */
+static void cn_queue_create(struct work_struct *work)
+{
+ struct cn_queue_dev *dev;
+
+ dev = container_of(work, struct cn_queue_dev, wq_creation);
+
+ dev->cn_queue = create_singlethread_workqueue(dev->name);
+ /* If we fail, we will use keventd for all following connector jobs */
+ WARN_ON(!dev->cn_queue);
+}
+
+/*
+ * Queue a data sent to a callback.
+ * If the connector workqueue is already created, we queue the job on it.
+ * Otherwise, we queue the job to kevent and queue the connector workqueue
+ * creation too.
+ */
+int queue_cn_work(struct cn_callback_entry *cbq, struct work_struct *work)
+{
+ struct cn_queue_dev *pdev = cbq->pdev;
+
+ if (likely(pdev->cn_queue))
+ return queue_work(pdev->cn_queue, work);
+
+ /* Don't create the connector workqueue twice */
+ if (atomic_inc_return(&pdev->wq_requested) == 1)
+ schedule_work(&pdev->wq_creation);
+ else
+ atomic_dec(&pdev->wq_requested);
+
+ return schedule_work(work);
+}
+