/* refills descriptors in the rx chain: allocates skbs and iommu-maps them.  */
static void spider_net_refill_rx_chain(struct spider_net_card *card)
/* refills descriptors in the rx chain: allocates skbs and iommu-maps them.  */
static void spider_net_refill_rx_chain(struct spider_net_card *card)
{
	struct spider_net_descr_chain *chain = &card->rx_chain;
	unsigned long flags;
	if (!spin_trylock_irqsave(&chain->lock, flags))
		return;
	while (spider_net_get_descr_status(chain->head->hwdescr) ==
			SPIDER_NET_DESCR_NOT_IN_USE) {
		if (spider_net_prepare_rx_descr(card, chain->head))
			break;
		chain->head = chain->head->next;
	}
	spin_unlock_irqrestore(&chain->lock, flags);
}