dpdk driver probe

参考：  https://blog.csdn.net/jeawayfox/article/details/105444104

net/hns3/hns3_ethdev.c:4918:    return rte_eth_dev_pci_generic_probe(pci_dev,

rte_eal_init
   rte_bus_scan 
       rte_pci_scan
        rte_bus_probe

rte_eth_dev_pci_generic_probe(struct rte_pci_device *pci_dev,
        size_t private_data_size, eth_dev_pci_callback_t dev_init)
{
        struct rte_eth_dev *eth_dev;
        int ret;

        eth_dev = rte_eth_dev_pci_allocate(pci_dev, private_data_size);
        if (!eth_dev)
                return -ENOMEM;

        RTE_FUNC_PTR_OR_ERR_RET(*dev_init, -EINVAL);
        ret = dev_init(eth_dev);
        if (ret)
                rte_eth_dev_pci_release(eth_dev);
        else
                rte_eth_dev_probing_finish(eth_dev);

        return ret;
}
rte_eth_dev_pci_allocate
     rte_eth_dev_allocate(name)
struct rte_eth_dev *
rte_eth_dev_allocated(const char *name)
{
        struct rte_eth_dev *ethdev;

        rte_eth_dev_shared_data_prepare();

        rte_spinlock_lock(&rte_eth_dev_shared_data->ownership_lock);

        ethdev = _rte_eth_dev_allocated(name);

        rte_spinlock_unlock(&rte_eth_dev_shared_data->ownership_lock);

        return ethdev;
}

static struct rte_eth_dev *
_rte_eth_dev_allocated(const char *name)
{
        unsigned i;

        for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
                if (rte_eth_devices[i].data != NULL &&
                    strcmp(rte_eth_devices[i].data->name, name) == 0)
                        return &rte_eth_devices[i];
        }
        return NULL;
}

struct rte_eth_dev *
rte_eth_dev_allocate(const char *name)
{
    uint16_t port_id;
    struct rte_eth_dev *eth_dev = NULL;
    
    //申请进程间共享的data数据，用作挂到eth_dev->data下。
    rte_eth_dev_shared_data_prepare();

    /* Synchronize port creation between primary and secondary threads. */
    rte_spinlock_lock(&rte_eth_dev_shared_data->ownership_lock);
    
    //check一下，此name是否已经被申请。
    if (_rte_eth_dev_allocated(name) != NULL) {
        RTE_ETHDEV_LOG(ERR,
            "Ethernet device with name %s already allocated
",
            name);
        goto unlock;
    }
    
    //找到第一个free的port id号。
    port_id = rte_eth_dev_find_free_port();
    if (port_id == RTE_MAX_ETHPORTS) {
        RTE_ETHDEV_LOG(ERR,
            "Reached maximum number of Ethernet ports
");
        goto unlock;
    }
    
    //返回全局变量数组rte_eth_devices[port_id]，同时把上面申请到的共享data数据，正式挂到eth_dev->data下。
    eth_dev = eth_dev_get(port_id);
    snprintf(eth_dev->data->name, sizeof(eth_dev->data->name), "%s", name);
    eth_dev->data->port_id = port_id;
    eth_dev->data->mtu = ETHER_MTU;

unlock:
    rte_spinlock_unlock(&rte_eth_dev_shared_data->ownership_lock);

    return eth_dev;
}