session_set_save_handler函数问题，在自定义的处理函数中不能调用数据库类，求解

<?php
/*
session_set_save_handler函数来自定义处理会话数据
session_set_save_handler(打开函数，关闭函数，读取函数，写入函数，清楚当前数据函数，清楚全部数据函数）；
*/
include '../mc.php';
$dbsql = new dbsql;
global $dbsql;
function mysql_session_open($session_path = '',$session_name = ''){
global $dbsql;
$config = array('dbhost'=>'localhost','dbuser'=>'root','dbpassword'=>'admin','dbname'=>'myweb','dbcharset'=>'GBK');
$dbsql->open(false,$config);
}

function mysql_session_close(){
global $dbsql;
//$dbsql->destory_result();
}

function mysql_session_read($sid = ''){
global $dbsql;
$sid = session_id();
if(empty($sid)){
return null;
}else{
$data = 'value';
$where = 'sid=\''.$sid.'\'';
return $dbsql->read($data,'uselogin',$where);
}
}

function mysql_session_write($sid = ''){
global $dbsql;
$sid = session_id();
$time = time(); $name = 'name';
$_SESSION['name'] = 'name';$_SESSION['sex'] = '0';
$value = session_encode();
$values = array('sid'=>$sid,'name'=>'name','time'=>$time,'value'=>$value);
$dbsql->in_data($values,'uselogin');//报错行
}

function mysql_session_destory(){

}

function mysql_session_des_all(){

}

session_set_save_handler('mysql_session_open','mysql_session_close','mysql_session_read','mysql_session_write','mysql_session_destory','mysql_session_des_all');
session_start();

错误提示：

Fatal error: Call to a member function in_data() on a non-object in F:\AppServ\www\createwebcms\session\session.php on line 39