Как отбраковать из коллекции отсутствующие на складе товары

/** @var  Mage_Catalog_Model_Resource_Eav_Mysql4_Product_Collection $products */
$products = Mage::getModel ('catalog/product')->getCollection();



$products->addAttributeToSelect ("*");



/** @var Mage_CatalogInventory_Model_Stock $stock */
$stock = Mage::getSingleton('cataloginventory/stock');



$stock->addInStockFilterToCollection ($products);