alloc_netdev() 与alloc_etherdev()区别

alloc_netdev()函数生成一个net_device结构体，对其成员赋值并返回该结构体的指针。第一个参数是设备私有成员的大小，第二个参数为设备名，第三个参数为net_device的setup()函数指针。setup()函数接收的参数为struct net_device指针，用于预置net_device成员的值。


linux-2.6.22/net/core/dev.c
----------------------------------------
struct net_device *alloc_netdev(int sizeof_priv, const char *name,
                void (*setup)(struct net_device *))
{
        void *p;
        struct net_device *dev;
        int alloc_size;

        BUG_ON(strlen(name) >= sizeof(dev->name));

        /* ensure 32-byte alignment of both the device and private area */
        alloc_size = (sizeof(*dev) + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST;
        alloc_size += sizeof_priv + NETDEV_ALIGN_CONST;

        p = kzalloc(alloc_size, GFP_KERNEL);
        if (!p) {
                printk(KERN_ERR "alloc_netdev: Unable to allocate device.\n");
                return NULL;
        }

        dev = (struct net_device *)
                (((long)p + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST);
        dev->padded = (char *)dev - (char *)p;

        if (sizeof_priv)
                dev->priv = netdev_priv(dev);

        dev->get_stats = internal_stats;
        setup(dev);
        strcpy(dev->name, name);
        return dev;
}

alloc_etherdev()是alloc_netdev()针对以太网的"快捷"函数

linux-2.6.22/net/ethernet/eth.c
----------------------------------------
struct net_device *alloc_etherdev(int sizeof_priv)
{
----returnalloc_netdev(sizeof_priv, "eth%d",ether_setup);
}


          net_device
+--------------+
|              |
|--------------|
|  base_addr   |
|--------------|
|              |
|              |
|--------------|
|  priv        | ---+
|--------------|   |
|              |   |
|              |   |
+--------------+ <--+
|              |
|              | sizeof_priv
|              |
+--------------+