Jon, On Fri, Jul 13, 2012 at 5:44 PM, Jon Mason <jon.mason@xxxxxxxxx> wrote: .............. > +/** > + * ntb_ring_sdb() - Set the doorbell on the secondary/external side > + * @ndev: pointer to ntb_device instance > + * @db: doorbell to ring > + * > + * This function allows triggering of a doorbell on the secondary/external > + * side that will initiate an interrupt on the remote host > + * > + * RETURNS: An appropriate -ERRNO error value on error, or zero for success. > + */ > +int ntb_ring_sdb(struct ntb_device *ndev, unsigned int db) > +{ > + dev_dbg(&ndev->pdev->dev, "%s: ringing doorbell %d\n", __func__, db); > + > + if (db >= ndev->max_cbs) > + return -EINVAL; How about moving this max_cbs error check in the upper level callers(example in ntb_process_tx)? That way you won't have to defer handling some negative cases all the way till the end. So ntb_process_tx could now look like: ..... error=0; if (entry->len > transport_mtu) { ... error=1; } else if (qp->qp_num >= qp->ndev->max_cbs) { ... error=1; } if (unlikely(error)) { ntb_list_add_tail(&qp->txc_lock, &entry->entry, &qp->txc); if (qp->tx_handler) qp->tx_handler(qp); return 0; } ................. No further comments below > + > +static int ntb_process_tx(struct ntb_transport_qp *qp, > + struct ntb_queue_entry *entry) > +{ > + struct ntb_payload_header *hdr; > + void *offset; > + > + offset = qp->tx_offset; > + hdr = offset; > + > + pr_debug("%lld - offset %p, tx %p, entry len %d flags %x buff %p\n", > + qp->tx_pkts, offset, qp->tx_offset, entry->len, entry->flags, > + entry->buf); > + if (hdr->flags) { > + ntb_list_add_head(&qp->txq_lock, &entry->entry, &qp->txq); > + qp->tx_ring_full++; > + return -EAGAIN; > + } > + > + if (entry->len > transport_mtu) { > + pr_err("Trying to send pkt size of %d\n", entry->len); > + entry->flags = HW_ERROR_FLAG; > + > + ntb_list_add_tail(&qp->txc_lock, &entry->entry, &qp->txc); > + > + if (qp->tx_handler) > + qp->tx_handler(qp); > + > + return 0; > + } > + > + ntb_tx_copy_task(qp, entry, offset); > + > + qp->tx_offset = > + (qp->tx_offset + > + ((transport_mtu + sizeof(struct ntb_payload_header)) * 2) >= > + qp->tx_mw_end) ? qp->tx_mw_begin : qp->tx_offset + transport_mtu + > + sizeof(struct ntb_payload_header); > + > + qp->tx_pkts++; > + > + return 0; > +} > + Chetan Loke -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html