+ /*
+ * No need for threads to be pending here, they can leave the first
+ * taker all the work.
+ *
+ * mvmtxq->tx_request logic:
+ *
+ * If 0, no one is currently TXing, set to 1 to indicate current thread
+ * will now start TX and other threads should quit.
+ *
+ * If 1, another thread is currently TXing, set to 2 to indicate to
+ * that thread that there was another request. Since that request may
+ * have raced with the check whether the queue is empty, the TXing
+ * thread should check the queue's status one more time before leaving.
+ * This check is done in order to not leave any TX hanging in the queue
+ * until the next TX invocation (which may not even happen).
+ *
+ * If 2, another thread is currently TXing, and it will already double
+ * check the queue, so do nothing.
+ */
+ if (atomic_fetch_add_unless(&mvmtxq->tx_request, 1, 2))
+ return;