static int rio_rx_data_handler()

in rio_cm.c [526:575]

• 36 lines of code
• 4 McCabe index (conditional complexity)

static int rio_rx_data_handler(struct cm_dev *cm, void *buf)
{
	struct rio_ch_chan_hdr *hdr;
	struct rio_channel *ch;

	hdr = buf;

	riocm_debug(RX_DATA, "for ch=%d", ntohs(hdr->dst_ch));

	ch = riocm_get_channel(ntohs(hdr->dst_ch));
	if (!ch) {
		/* Discard data message for non-existing channel */
		kfree(buf);
		return -ENODEV;
	}

	/* Place pointer to the buffer into channel's RX queue */
	spin_lock(&ch->lock);

	if (ch->state != RIO_CM_CONNECTED) {
		/* Channel is not ready to receive data, discard a packet */
		riocm_debug(RX_DATA, "ch=%d is in wrong state=%d",
			    ch->id, ch->state);
		spin_unlock(&ch->lock);
		kfree(buf);
		riocm_put_channel(ch);
		return -EIO;
	}

	if (ch->rx_ring.count == RIOCM_RX_RING_SIZE) {
		/* If RX ring is full, discard a packet */
		riocm_debug(RX_DATA, "ch=%d is full", ch->id);
		spin_unlock(&ch->lock);
		kfree(buf);
		riocm_put_channel(ch);
		return -ENOMEM;
	}

	ch->rx_ring.buf[ch->rx_ring.head] = buf;
	ch->rx_ring.head++;
	ch->rx_ring.count++;
	ch->rx_ring.head %= RIOCM_RX_RING_SIZE;

	complete(&ch->comp);

	spin_unlock(&ch->lock);
	riocm_put_channel(ch);

	return 0;
}