On Sun, Jul 29, 2012 at 8:26 PM, Jon Mason [off-list ref] wrote:

<snip>

+static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
+                            struct ntb_queue_entry *entry,
+                            void *offset)
+{
+       struct ntb_payload_header *hdr = offset;
+
+       offset += sizeof(struct ntb_payload_header);
+       memcpy_toio(offset, entry->buf, entry->len);
+
+       hdr->len = entry->len;
+       hdr->ver = qp->tx_pkts;
+
+       /* Ensure that the data is fully copied out before setting the flag */
+       wmb();
+       hdr->flags = entry->flags | DESC_DONE_FLAG;
+
+       ntb_ring_sdb(qp->ndev, qp->qp_num);
+
+       /* The entry length can only be zero if the packet is intended to be a
+        * "link down" or similar.  Since no payload is being sent in these
+        * cases, there is nothing to add to the completion queue.
+        */
+       if (entry->len > 0) {
+               qp->tx_bytes += entry->len;
+
+               /* Add fully transmitted data to completion queue */
+               ntb_list_add_tail(&qp->ntb_tx_comp_q_lock, &entry->entry,
+                                 &qp->tx_comp_q);
+
+               if (qp->tx_handler)
+                       qp->tx_handler(qp->cb_data, qp);
+       } else
+               ntb_list_add_tail(&qp->ntb_tx_free_q_lock, &entry->entry,
+                                 &qp->tx_free_q);
+}

I know you talked about a fixed array. But it's not here yet. So at
all the call-sites, for [r/t]x_free_q , add the 'entry' to the head -
change to ntb_list_add_head here and else where.

Chetan Loke