static int nbd_genl_connect()

in nbd.c [1907:2078]

• 155 lines of code
• 36 McCabe index (conditional complexity)

static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
{
	struct nbd_device *nbd;
	struct nbd_config *config;
	int index = -1;
	int ret;
	bool put_dev = false;

	if (!netlink_capable(skb, CAP_SYS_ADMIN))
		return -EPERM;

	if (info->attrs[NBD_ATTR_INDEX])
		index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
	if (!info->attrs[NBD_ATTR_SOCKETS]) {
		printk(KERN_ERR "nbd: must specify at least one socket\n");
		return -EINVAL;
	}
	if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
		printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
		return -EINVAL;
	}
again:
	mutex_lock(&nbd_index_mutex);
	if (index == -1) {
		nbd = nbd_find_get_unused();
	} else {
		nbd = idr_find(&nbd_index_idr, index);
		if (nbd) {
			if ((test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
			     test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) ||
			    !refcount_inc_not_zero(&nbd->refs)) {
				mutex_unlock(&nbd_index_mutex);
				pr_err("nbd: device at index %d is going down\n",
					index);
				return -EINVAL;
			}
		}
	}
	mutex_unlock(&nbd_index_mutex);

	if (!nbd) {
		nbd = nbd_dev_add(index, 2);
		if (IS_ERR(nbd)) {
			pr_err("nbd: failed to add new device\n");
			return PTR_ERR(nbd);
		}
	}

	mutex_lock(&nbd->config_lock);
	if (refcount_read(&nbd->config_refs)) {
		mutex_unlock(&nbd->config_lock);
		nbd_put(nbd);
		if (index == -1)
			goto again;
		printk(KERN_ERR "nbd: nbd%d already in use\n", index);
		return -EBUSY;
	}
	if (WARN_ON(nbd->config)) {
		mutex_unlock(&nbd->config_lock);
		nbd_put(nbd);
		return -EINVAL;
	}
	config = nbd->config = nbd_alloc_config();
	if (!nbd->config) {
		mutex_unlock(&nbd->config_lock);
		nbd_put(nbd);
		printk(KERN_ERR "nbd: couldn't allocate config\n");
		return -ENOMEM;
	}
	refcount_set(&nbd->config_refs, 1);
	set_bit(NBD_RT_BOUND, &config->runtime_flags);

	ret = nbd_genl_size_set(info, nbd);
	if (ret)
		goto out;

	if (info->attrs[NBD_ATTR_TIMEOUT])
		nbd_set_cmd_timeout(nbd,
				    nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
	if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
		config->dead_conn_timeout =
			nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
		config->dead_conn_timeout *= HZ;
	}
	if (info->attrs[NBD_ATTR_SERVER_FLAGS])
		config->flags =
			nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
	if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
		u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
		if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
			/*
			 * We have 1 ref to keep the device around, and then 1
			 * ref for our current operation here, which will be
			 * inherited by the config.  If we already have
			 * DESTROY_ON_DISCONNECT set then we know we don't have
			 * that extra ref already held so we don't need the
			 * put_dev.
			 */
			if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
					      &nbd->flags))
				put_dev = true;
		} else {
			if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
					       &nbd->flags))
				refcount_inc(&nbd->refs);
		}
		if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
			set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
				&config->runtime_flags);
		}
	}

	if (info->attrs[NBD_ATTR_SOCKETS]) {
		struct nlattr *attr;
		int rem, fd;

		nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
				    rem) {
			struct nlattr *socks[NBD_SOCK_MAX+1];

			if (nla_type(attr) != NBD_SOCK_ITEM) {
				printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
				ret = -EINVAL;
				goto out;
			}
			ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
							  attr,
							  nbd_sock_policy,
							  info->extack);
			if (ret != 0) {
				printk(KERN_ERR "nbd: error processing sock list\n");
				ret = -EINVAL;
				goto out;
			}
			if (!socks[NBD_SOCK_FD])
				continue;
			fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
			ret = nbd_add_socket(nbd, fd, true);
			if (ret)
				goto out;
		}
	}
	ret = nbd_start_device(nbd);
	if (ret)
		goto out;
	if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
		nbd->backend = nla_strdup(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
					  GFP_KERNEL);
		if (!nbd->backend) {
			ret = -ENOMEM;
			goto out;
		}
	}
	ret = device_create_file(disk_to_dev(nbd->disk), &backend_attr);
	if (ret) {
		dev_err(disk_to_dev(nbd->disk),
			"device_create_file failed for backend!\n");
		goto out;
	}
	set_bit(NBD_RT_HAS_BACKEND_FILE, &config->runtime_flags);
out:
	mutex_unlock(&nbd->config_lock);
	if (!ret) {
		set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
		refcount_inc(&nbd->config_refs);
		nbd_connect_reply(info, nbd->index);
	}
	nbd_config_put(nbd);
	if (put_dev)
		nbd_put(nbd);
	return ret;
}