netif_stop_subqueue函数分析

*      netif_stop_subqueue - stop sending packets on subqueue*      @dev: network device*      @queue_index: sub queue index** Stop individual transmit queue of a device with multiple transmit queues.*/static inline void netif_stop_subqueue(struct net_device *dev, u16 queue_index){    struct netdev_queue *txq = netdev_get_tx_queue(dev, queue_index);    netif_tx_stop_queue(txq);}

static inline void netif_tx_stop_queue(struct netdev_queue *dev_queue){       if (WARN_ON(!dev_queue)) {                pr_info("netif_stop_queue() cannot be called before register_netdev()\n");                return;        }        set_bit(__QUEUE_STATE_DRV_XOFF, &dev_queue->state);}