rswitch_next_queue_index
gq->cur = rswitch_next_queue_index(gq, true, 1);
gq->dirty = rswitch_next_queue_index(gq, false, num);
desc = &gq->tx_ring[rswitch_next_queue_index(gq, true, i)];
gq->cur = rswitch_next_queue_index(gq, true, nr_desc);
gq->cur = rswitch_next_queue_index(gq, true, 1);
gq->dirty = rswitch_next_queue_index(gq, false, num);
gq->dirty = rswitch_next_queue_index(gq, false, 1);