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；
1 static int __init net_dev_init(void) 2 { 3 int i, rc = -ENOMEM; 4 5 BUG_ON(!dev_boot_phase); 6 7 //初始化统计信息的proc文件 8 if (dev_proc_init()) 9 goto out; 10 11 //初始化kobject 12 if (netdev_kobject_init()) 13 goto out; 14 15 //初始化协议类型链表 16 INIT_LIST_HEAD(&ptype_all); 17 18 //初始化协议类型hash表 19 for (i = 0; i < PTYPE_HASH_SIZE; i++) 20 INIT_LIST_HEAD(&ptype_base[i]); 21 22 //初始化offload列表 23 INIT_LIST_HEAD(&offload_base); 24 25 //注册网络命名空间子系统 26 if (register_pernet_subsys(&netdev_net_ops)) 27 goto out; 28 29 /* 30 * Initialise the packet receive queues. 31 */ 32 //初始化数据包接收队列 33 for_each_possible_cpu(i) { 34 struct work_struct *flush = per_cpu_ptr(&flush_works, i); 35 struct softnet_data *sd = &per_cpu(softnet_data, i); 36 37 //初始化清理backlog队列 38 INIT_WORK(flush, flush_backlog); 39 40 //初始化非napi接口层的缓存队列 41 skb_queue_head_init(&sd->input_pkt_queue); 42 43 //初始化数据包处理队列 44 skb_queue_head_init(&sd->process_queue); 45 46 //初始化网络设备轮询队列 47 INIT_LIST_HEAD(&sd->poll_list); 48 49 //初始化输出队列尾部 50 sd->output_queue_tailp = &sd->output_queue; 51 52 //若支持RPS 53 #ifdef CONFIG_RPS 54 sd->csd.func = rps_trigger_softirq; 55 sd->csd.info = sd; 56 sd->cpu = i; 57 #endif 58 59 //支持非napi虚拟设备的回调和配额设置 60 sd->backlog.poll = process_backlog; 61 sd->backlog.weight = weight_p; 62 } 63 64 dev_boot_phase = 0; 65 66 /* The loopback device is special if any other network devices 67 * is present in a network namespace the loopback device must 68 * be present. Since we now dynamically allocate and free the 69 * loopback device ensure this invariant is maintained by 70 * keeping the loopback device as the first device on the 71 * list of network devices. Ensuring the loopback devices 72 * is the first device that appears and the last network device 73 * that disappears. 74 */ 75 //注册回环设备 76 if (register_pernet_device(&loopback_net_ops)) 77 goto out; 78 79 if (register_pernet_device(&default_device_ops)) 80 goto out; 81 82 //注册发送软中断 83 open_softirq(NET_TX_SOFTIRQ, net_tx_action); 84 85 //注册接收软中断 86 open_softirq(NET_RX_SOFTIRQ, net_rx_action); 87 88 //注册响应cpu状态变化的回调 89 rc = cpuhp_setup_state_nocalls(CPUHP_NET_DEV_DEAD, "net/dev:dead", 90 NULL, dev_cpu_dead); 91 WARN_ON(rc < 0); 92 93 //注册响应网络状态变化的回调 94 dst_subsys_init(); 95 rc = 0; 96 out: 97 return rc; 98 }