int drbd_adm_dump_connections()

in drbd/drbd_nl.c [3499:3615]
107 lines of code
20 McCabe index (conditional complexity)

int drbd_adm_dump_connections(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct nlattr *resource_filter;
	struct drbd_resource *resource = NULL, *next_resource;
	struct drbd_connection *connection;
	int err = 0, retcode;
	struct drbd_genlmsghdr *dh;
	struct connection_info connection_info;
	struct connection_statistics connection_statistics;

	rcu_read_lock();
	resource = (struct drbd_resource *)cb->args[0];
	if (!cb->args[0]) {
		resource_filter = find_cfg_context_attr(cb->nlh, T_ctx_resource_name);
		if (resource_filter) {
			retcode = ERR_RES_NOT_KNOWN;
			resource = drbd_find_resource(nla_data(resource_filter));
			if (!resource)
				goto put_result;
			cb->args[0] = (long)resource;
			cb->args[1] = SINGLE_RESOURCE;
		}
	}
	if (!resource) {
		if (list_empty(&drbd_resources))
			goto out;
		resource = list_first_entry(&drbd_resources, struct drbd_resource, resources);
		kref_get(&resource->kref);
		cb->args[0] = (long)resource;
		cb->args[1] = ITERATE_RESOURCES;
	}

    next_resource:
	rcu_read_unlock();
	mutex_lock(&resource->conf_update);
	rcu_read_lock();
	if (cb->args[2]) {
		for_each_connection_rcu(connection, resource)
			if (connection == (struct drbd_connection *)cb->args[2])
				goto found_connection;
		/* connection was probably deleted */
		goto no_more_connections;
	}
	connection = list_entry(&resource->connections, struct drbd_connection, connections);

found_connection:
	list_for_each_entry_continue_rcu(connection, &resource->connections, connections) {
		if (!has_net_conf(connection))
			continue;
		retcode = NO_ERROR;
		goto put_result;  /* only one iteration */
	}

no_more_connections:
	if (cb->args[1] == ITERATE_RESOURCES) {
		for_each_resource_rcu(next_resource, &drbd_resources) {
			if (next_resource == resource)
				goto found_resource;
		}
		/* resource was probably deleted */
	}
	goto out;

found_resource:
	list_for_each_entry_continue_rcu(next_resource, &drbd_resources, resources) {
		mutex_unlock(&resource->conf_update);
		kref_put(&resource->kref, drbd_destroy_resource);
		resource = next_resource;
		kref_get(&resource->kref);
		cb->args[0] = (long)resource;
		cb->args[2] = 0;
		goto next_resource;
	}
	goto out;  /* no more resources */

put_result:
	dh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
			cb->nlh->nlmsg_seq, &drbd_genl_family,
			NLM_F_MULTI, DRBD_ADM_GET_CONNECTIONS);
	err = -ENOMEM;
	if (!dh)
		goto out;
	dh->ret_code = retcode;
	dh->minor = -1U;
	if (retcode == NO_ERROR) {
		struct net_conf *net_conf;

		err = nla_put_drbd_cfg_context(skb, resource, connection, NULL);
		if (err)
			goto out;
		net_conf = rcu_dereference(connection->net_conf);
		if (net_conf) {
			err = net_conf_to_skb(skb, net_conf, !capable(CAP_SYS_ADMIN));
			if (err)
				goto out;
		}
		connection_to_info(&connection_info, connection);
		err = connection_info_to_skb(skb, &connection_info, !capable(CAP_SYS_ADMIN));
		if (err)
			goto out;
		connection_statistics.conn_congested = test_bit(NET_CONGESTED, &connection->flags);
		err = connection_statistics_to_skb(skb, &connection_statistics, !capable(CAP_SYS_ADMIN));
		if (err)
			goto out;
		cb->args[2] = (long)connection;
	}
	genlmsg_end(skb, dh);
	err = 0;

out:
	rcu_read_unlock();
	if (resource)
		mutex_unlock(&resource->conf_update);
	if (err)
		return err;
	return skb->len;
}