static int reserve_or_set_tx()

in eni.c [1285:1370]

• 85 lines of code
• 39 McCabe index (conditional complexity)

static int reserve_or_set_tx(struct atm_vcc *vcc,struct atm_trafprm *txtp,
    int set_rsv,int set_shp)
{
	struct eni_dev *eni_dev = ENI_DEV(vcc->dev);
	struct eni_vcc *eni_vcc = ENI_VCC(vcc);
	struct eni_tx *tx;
	unsigned long size;
	void __iomem *mem;
	int rate,ubr,unlimited,new_tx;
	int pre,res,order;
	int error;

	rate = atm_pcr_goal(txtp);
	ubr = txtp->traffic_class == ATM_UBR;
	unlimited = ubr && (!rate || rate <= -ATM_OC3_PCR ||
	    rate >= ATM_OC3_PCR);
	if (!unlimited) {
		size = txtp->max_sdu*eni_dev->tx_mult/100;
		if (size > MID_MAX_BUF_SIZE && txtp->max_sdu <=
		    MID_MAX_BUF_SIZE)
			size = MID_MAX_BUF_SIZE;
	}
	else {
		if (eni_dev->ubr) {
			eni_vcc->tx = eni_dev->ubr;
			txtp->pcr = ATM_OC3_PCR;
			return 0;
		}
		size = UBR_BUFFER;
	}
	new_tx = !eni_vcc->tx;
	mem = NULL; /* for gcc */
	if (!new_tx) tx = eni_vcc->tx;
	else {
		mem = eni_alloc_mem(eni_dev,&size);
		if (!mem) return -ENOBUFS;
		tx = alloc_tx(eni_dev,unlimited);
		if (!tx) {
			eni_free_mem(eni_dev,mem,size);
			return -EBUSY;
		}
		DPRINTK("got chan %d\n",tx->index);
		tx->reserved = tx->shaping = 0;
		tx->send = mem;
		tx->words = size >> 2;
		skb_queue_head_init(&tx->backlog);
		for (order = 0; size > (1 << (order+10)); order++);
		eni_out((order << MID_SIZE_SHIFT) |
		    ((tx->send-eni_dev->ram) >> (MID_LOC_SKIP+2)),
		    MID_TX_PLACE(tx->index));
		tx->tx_pos = eni_in(MID_TX_DESCRSTART(tx->index)) &
		    MID_DESCR_START;
	}
	error = comp_tx(eni_dev,&rate,tx->reserved,&pre,&res,unlimited);
	if (!error  && txtp->min_pcr > rate) error = -EINVAL;
	if (!error && txtp->max_pcr && txtp->max_pcr != ATM_MAX_PCR &&
	    txtp->max_pcr < rate) error = -EINVAL;
	if (!error && !ubr && rate > eni_dev->tx_bw+tx->reserved)
		error = -EINVAL;
	if (!error && set_rsv && !set_shp && rate < tx->shaping)
		error = -EINVAL;
	if (!error && !set_rsv && rate > tx->reserved && !ubr)
		error = -EINVAL;
	if (error) {
		if (new_tx) {
			tx->send = NULL;
			eni_free_mem(eni_dev,mem,size);
		}
		return error;
	}
	txtp->pcr = rate;
	if (set_rsv && !ubr) {
		eni_dev->tx_bw += tx->reserved;
		tx->reserved = rate;
		eni_dev->tx_bw -= rate;
	}
	if (set_shp || (unlimited && new_tx)) {
		if (unlimited && new_tx) eni_dev->ubr = tx;
		tx->prescaler = pre;
		tx->resolution = res;
		tx->shaping = rate;
	}
	if (set_shp) eni_vcc->tx = tx;
	DPRINTK("rsv %d shp %d\n",tx->reserved,tx->shaping);
	return 0;
}