roce是网卡的一部分

roce分为软件实现的roce和硬件实现的roce，硬件roce就是在普通网卡中添加一个模块，其中pf和vf 都可以使用roce
由于roce是网卡的一部分，因此roce在初始化的时候是包含在网卡初始化中的过程中，例如下面这个roce就会注册
自己的初始化函数到网卡驱动中
static const struct hnae3_client_ops hns_roce_hw_v2_ops = {
	.init_instance = hns_roce_hw_v2_init_instance,
	.uninit_instance = hns_roce_hw_v2_uninit_instance,
};

static struct hnae3_client hns_roce_hw_v2_client = {
	.name = "hns_roce_hw_v2",
	.type = HNAE3_CLIENT_ROCE,
	.ops = &hns_roce_hw_v2_ops,
};

static int __init hns_roce_hw_v2_init(void)
{
	return hnae3_register_client(&hns_roce_hw_v2_client);
}
执行hnae3_register_client 后，就把roce的初始化函数添加到网卡驱动中
int hnae3_register_client(struct hnae3_client *client)
{
	struct hnae3_client *client_tmp;
	struct hnae3_ae_dev *ae_dev;
	int ret = 0;

	mutex_lock(&hnae3_common_lock);
	/* one system should only have one client for every type */
#检查一下roce是否已经加入到网口的初始化列表中，如果已经加入了，则不能重复加载，直接退出
	list_for_each_entry(client_tmp, &hnae3_client_list, node) {
		if (client_tmp->type == client->type)
			goto exit;
	}
#把client加到入到网卡中
	list_add_tail(&client->node, &hnae3_client_list);
#为网卡的每个口都添加roce的client
	/* initialize the client on every matched port */
	list_for_each_entry(ae_dev, &hnae3_ae_dev_list, node) {
		/* if the client could not be initialized on current port, for
		 * any error reasons, move on to next available port
		 */
		ret = hnae3_match_n_instantiate(client, ae_dev, true);
		if (ret)
			dev_err(&ae_dev->pdev->dev,
				"match 

}
将roce添加到网卡驱动中后，就会调用ib_register_device来注册roce驱动
这个函数第一个参数是要注册的device，一般在注册之前会将这个device 结构体的成员变量填充好。
int ib_register_device(struct ib_device *device,
		       int (*port_callback)(struct ib_device *,
					    u8, struct kobject *))
{
	int ret;
	struct ib_client *client;
	struct ib_udata uhw = {.outlen = 0, .inlen = 0};
	struct device *parent = device->dev.parent;

	WARN_ON_ONCE(device->dma_device);
#看这个设备是否提供dma操作的函数，这里dma操作分为一致性dma和流式dma
	if (device->dev.dma_ops) {
		/*
		 * The caller provided custom DMA operations. Copy the
		 * DMA-related fields that are used by e.g. dma_alloc_coherent()
		 * into device->dev.
		 */
		device->dma_device = &device->dev;
		if (!device->dev.dma_mask) {
			if (parent)
				device->dev.dma_mask = parent->dma_mask;
			else
				WARN_ON_ONCE(true);
		}
		mutex_lock(&device_mutex);
#ib 设备申请name
	if (strchr(device->name, '%')) {
		ret = alloc_name(device->name);
		if (ret)
			goto out;
	}
#检查device是否提供基础的roce功能
	if (ib_device_check_mandatory(device)) {
		ret = -EINVAL;
		goto out;
	}
#读取port和key
	ret = read_port_immutable(device);
	if (ret) {
		pr_warn("Couldn't create per port immutable data %s\n",
			device->name);
		goto out;
	}

	ret = setup_port_pkey_list(device);
	if (ret) {
		pr_warn("Couldn't create per port_pkey_list\n");
		goto out;
	}
#为ib设备建立cache
	ret = ib_cache_setup_one(device);
	if (ret) {
		pr_warn("Couldn't set up InfiniBand P_Key/GID cache\n");
		goto port_cleanup;
	}
#注册cgroup
	ret = ib_device_register_rdmacg(device);
	if (ret) {
		pr_warn("Couldn't register device with rdma cgroup\n");
		goto cache_cleanup;
	}
#查询设备的hw和attrs信息
	memset(&device->attrs, 0, sizeof(device->attrs));
	ret = device->query_device(device, &device->attrs, &uhw);
	if (ret) {
		pr_warn("Couldn't query the device attributes\n");
		goto cg_cleanup;
	}
#注册sysfs信息
	ret = ib_device_register_sysfs(device, port_callback);
	if (ret) {
		pr_warn("Couldn't register device %s with driver model\n",
			device->name);
		goto cg_cleanup;
	}

	device->reg_state = IB_DEV_REGISTERED;
#增加context
	list_for_each_entry(client, &client_list, list)
		if (!add_client_context(device, client) && client->add)
			client->add(device);

	device->index = __dev_new_index();
	down_write(&lists_rwsem);
#所有的roce设备都放在&device_list 中
	list_add_tail(&device->core_list, &device_list);
	up_write(&lists_rwsem);
	mutex_unlock(&device_mutex);
	return 0;

}