net_dev_init

Kernel: 4.12.6

网络设备初始化，主要包括初始化softnet_data，注册收发包软中断等；

 static int __init net_dev_init(void)
 {
     int i, rc = -ENOMEM;

     BUG_ON(!dev_boot_phase);

     //初始化统计信息的proc文件
     if (dev_proc_init())
         goto out;

     //初始化kobject
     if (netdev_kobject_init())
         goto out;

     //初始化协议类型链表
     INIT_LIST_HEAD(&ptype_all);

     //初始化协议类型hash表
     for (i = ; i < PTYPE_HASH_SIZE; i++)
         INIT_LIST_HEAD(&ptype_base[i]);

     //初始化offload列表
     INIT_LIST_HEAD(&offload_base);

     //注册网络命名空间子系统
     if (register_pernet_subsys(&netdev_net_ops))
         goto out;

     /*
      *    Initialise the packet receive queues.
      */
     //初始化数据包接收队列
     for_each_possible_cpu(i) {
         struct work_struct *flush = per_cpu_ptr(&flush_works, i);
         struct softnet_data *sd = &per_cpu(softnet_data, i);

         //初始化清理backlog队列
         INIT_WORK(flush, flush_backlog);

         //初始化非napi接口层的缓存队列
         skb_queue_head_init(&sd->input_pkt_queue);

         //初始化数据包处理队列
         skb_queue_head_init(&sd->process_queue);

         //初始化网络设备轮询队列
         INIT_LIST_HEAD(&sd->poll_list);

         //初始化输出队列尾部
         sd->output_queue_tailp = &sd->output_queue;

         //若支持RPS
 #ifdef CONFIG_RPS
         sd->csd.func = rps_trigger_softirq;
         sd->csd.info = sd;
         sd->cpu = i;
 #endif

         //支持非napi虚拟设备的回调和配额设置
         sd->backlog.poll = process_backlog;
         sd->backlog.weight = weight_p;
     }

     dev_boot_phase = ;

     /* The loopback device is special if any other network devices
      * is present in a network namespace the loopback device must
      * be present. Since we now dynamically allocate and free the
      * loopback device ensure this invariant is maintained by
      * keeping the loopback device as the first device on the
      * list of network devices.  Ensuring the loopback devices
      * is the first device that appears and the last network device
      * that disappears.
      */
     //注册回环设备
     if (register_pernet_device(&loopback_net_ops))
         goto out;

     if (register_pernet_device(&default_device_ops))
         goto out;

     //注册发送软中断
     open_softirq(NET_TX_SOFTIRQ, net_tx_action);

     //注册接收软中断
     open_softirq(NET_RX_SOFTIRQ, net_rx_action);

     //注册响应cpu状态变化的回调
     rc = cpuhp_setup_state_nocalls(CPUHP_NET_DEV_DEAD, "net/dev:dead",
                        NULL, dev_cpu_dead);
     WARN_ON(rc < );

     //注册响应网络状态变化的回调
     dst_subsys_init();
     rc = ;
 out:
     return rc;
 }