static int nbd_genl_reconfigure()

in nbd.c [2136:2275]
130 lines of code
26 McCabe index (conditional complexity)

static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
{
	struct nbd_device *nbd = NULL;
	struct nbd_config *config;
	int index;
	int ret = 0;
	bool put_dev = false;

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

	if (!info->attrs[NBD_ATTR_INDEX]) {
		printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
		return -EINVAL;
	}
	index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
	mutex_lock(&nbd_index_mutex);
	nbd = idr_find(&nbd_index_idr, index);
	if (!nbd) {
		mutex_unlock(&nbd_index_mutex);
		printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
		       index);
		return -EINVAL;
	}
	if (nbd->backend) {
		if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
			if (nla_strcmp(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
				       nbd->backend)) {
				mutex_unlock(&nbd_index_mutex);
				dev_err(nbd_to_dev(nbd),
					"backend image doesn't match with %s\n",
					nbd->backend);
				return -EINVAL;
			}
		} else {
			mutex_unlock(&nbd_index_mutex);
			dev_err(nbd_to_dev(nbd), "must specify backend\n");
			return -EINVAL;
		}
	}
	if (!refcount_inc_not_zero(&nbd->refs)) {
		mutex_unlock(&nbd_index_mutex);
		printk(KERN_ERR "nbd: device at index %d is going down\n",
		       index);
		return -EINVAL;
	}
	mutex_unlock(&nbd_index_mutex);

	if (!refcount_inc_not_zero(&nbd->config_refs)) {
		dev_err(nbd_to_dev(nbd),
			"not configured, cannot reconfigure\n");
		nbd_put(nbd);
		return -EINVAL;
	}

	mutex_lock(&nbd->config_lock);
	config = nbd->config;
	if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
	    !nbd->pid) {
		dev_err(nbd_to_dev(nbd),
			"not configured, cannot reconfigure\n");
		ret = -EINVAL;
		goto out;
	}

	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_CLIENT_FLAGS]) {
		u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
		if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
			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);
		} else {
			clear_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_reconnect_socket(nbd, fd);
			if (ret) {
				if (ret == -ENOSPC)
					ret = 0;
				goto out;
			}
			dev_info(nbd_to_dev(nbd), "reconnected socket\n");
		}
	}
out:
	mutex_unlock(&nbd->config_lock);
	nbd_config_put(nbd);
	nbd_put(nbd);
	if (put_dev)
		nbd_put(nbd);
	return ret;
}