FreeBSD/sys/dev/xen/netfront/netfront.c
/**
 * \brief Verify that there is sufficient space in the Tx ring
 *        buffer for a maximally sized request to be enqueued.
 *
 * A transmit request requires a transmit descriptor for each packet
 * fragment, plus up to 2 entries for "options" (e.g. TSO).
 */
\brief Verify that there is sufficient space in the Tx ring
buffer for a maximally sized request to be enqueued.

A transmit request requires a transmit descriptor for each packet
fragment, plus up to 2 entries for "options" .
\ brief Verify that there is sufficient space in the Tx ring buffer for a maximally sized request to be enqueued . A transmit request requires a transmit descriptor for each packet fragment plus up to 2 entries for " options " .
static inline int
xn_tx_slot_available(struct netfront_txq *txq)
{
	return (RING_FREE_REQUESTS(&txq->ring) > (MAX_TX_REQ_FRAGS + 2));
}
static inline int xn_tx_slot_available ( struct netfront_txq * txq ) { return ( RING_FREE_REQUESTS ( & txq -> ring ) > ( MAX_TX_REQ_FRAGS + 2 ) ) ; }
\brief Verify that there is sufficient space in the Tx ring
        buffer for a maximally sized request to be enqueued.
\ brief Verify that there is sufficient space in the Tx ring buffer for a maximally sized request to be enqueued .