本文共 2445 字，大约阅读时间需要 8 分钟。

以3c359x.c的网卡为例，因为这是《深入理解Linux网络技术内幕》里面的例子

irqreturn_t vortex_interrupt(int irq, void *dev_id)	vortex_rx(dev);	=>int vortex_rx(struct net_device *dev)		struct vortex_private *vp = netdev_priv(dev);		void __iomem *ioaddr = vp->ioaddr;		short rx_status;		while ((rx_status = ioread16(ioaddr + RxStatus)) > 0)			int pkt_len = rx_status & 0x1fff;			struct sk_buff *skb = dev_alloc_skb(pkt_len + 5);			skb_reserve(skb, 2);	/* Align IP on 16 byte boundaries */			if (vp->bus_master && ! (ioread16(ioaddr + Wn7_MasterStatus) & 0x8000)) 				dma_addr_t dma = pci_map_single(VORTEX_PCI(vp), skb_put(skb, pkt_len), pkt_len, PCI_DMA_FROMDEVICE);				iowrite32(dma, ioaddr + Wn7_MasterAddr);				iowrite16((skb->len + 3) & ~3, ioaddr + Wn7_MasterLen);				iowrite16(StartDMAUp, ioaddr + EL3_CMD);				while (ioread16(ioaddr + Wn7_MasterStatus) & 0x8000)					;				pci_unmap_single(VORTEX_PCI(vp), dma, pkt_len, PCI_DMA_FROMDEVICE);			else 				ioread32_rep(ioaddr + RX_FIFO, skb_put(skb, pkt_len), (pkt_len + 3) >> 2);							iowrite16(RxDiscard, ioaddr + EL3_CMD); /* Pop top Rx packet. */			skb->protocol = eth_type_trans(skb, dev);			netif_rx(skb)			=>int netif_rx(struct sk_buff *skb)				if (queue->input_pkt_queue.qlen <= netdev_max_backlog)					if (queue->input_pkt_queue.qlen)			enqueue:						__skb_queue_tail(&queue->input_pkt_queue, skb);						return NET_RX_SUCCESS;											napi_schedule(&queue->backlog);					=>inline void napi_schedule(struct napi_struct *n)						if (napi_schedule_prep(n))							__napi_schedule(n);							=>void __napi_schedule(struct napi_struct *n)								list_add_tail(&n->poll_list, &__get_cpu_var(softnet_data).poll_list);								__raise_softirq_irqoff(NET_RX_SOFTIRQ);//唤醒软中断					goto enqueue;

收包软中断入口函数

void net_rx_action(struct softirq_action *h)	struct list_head *list = &__get_cpu_var(softnet_data).poll_list;	while (!list_empty(list))		n = list_first_entry(list, struct napi_struct, poll_list);		have = netpoll_poll_lock(n);		weight = n->weight;				n = list_first_entry(list, struct napi_struct, poll_list);		have = netpoll_poll_lock(n);		weight = n->weight;				work = 0;		if (test_bit(NAPI_STATE_SCHED, &n->state))			work = n->poll(n, weight);			=>int process_backlog(struct napi_struct *napi, int quota)					budget -= work;

Linux 网络协议栈开发代码分析篇之数据收发（一） —— netif_receive_skb()函数

Linux内核--网络栈实现分析（二）--数据包的传递过程（上）