iwlwifi: pcie: Refactor iwl_rxq_space

 */

static int iwl_rxq_space(const struct iwl_rxq *rxq)

{

	int s = rxq->read - rxq->write;

	if (s <= 0)

		s += RX_QUEUE_SIZE;

	/* keep some buffer to not confuse full and empty queue */

	s -= 2;

	if (s < 0)

		s = 0;

	return s;

	/* Make sure RX_QUEUE_SIZE is a power of 2 */

	BUILD_BUG_ON(RX_QUEUE_SIZE & (RX_QUEUE_SIZE - 1));

	/*

	 * There can be up to (RX_QUEUE_SIZE - 1) free slots, to avoid ambiguity

	 * between empty and completely full queues.

	 * The following is equivalent to modulo by RX_QUEUE_SIZE and is well

	 * defined for negative dividends.

	 */

	return (rxq->read - rxq->write - 1) & (RX_QUEUE_SIZE - 1);

}

/*