Tx data ring support was removed in a previous change
to add multi-seg transmit.  This change adds it back.

Fixes: 7ba5de417e3c ("vmxnet3: support multi-segment transmit")

Signed-off-by: Yong Wang <yongwang at vmware.com>
---
 doc/guides/rel_notes/release_2_3.rst |  5 +++++
 drivers/net/vmxnet3/vmxnet3_rxtx.c   | 17 ++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/doc/guides/rel_notes/release_2_3.rst 
b/doc/guides/rel_notes/release_2_3.rst
index 99de186..a23c8ac 100644
--- a/doc/guides/rel_notes/release_2_3.rst
+++ b/doc/guides/rel_notes/release_2_3.rst
@@ -15,6 +15,11 @@ EAL
 Drivers
 ~~~~~~~

+* **vmxnet3: restore tx data ring.**
+
+  Tx data ring has been shown to improve small pkt forwarding performance
+  on vSphere environment.
+

 Libraries
 ~~~~~~~~~
diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c 
b/drivers/net/vmxnet3/vmxnet3_rxtx.c
index 4de5d89..2202d31 100644
--- a/drivers/net/vmxnet3/vmxnet3_rxtx.c
+++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c
@@ -348,6 +348,7 @@ vmxnet3_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
                uint32_t first2fill, avail, dw2;
                struct rte_mbuf *txm = tx_pkts[nb_tx];
                struct rte_mbuf *m_seg = txm;
+               int copy_size = 0;

                /* Is this packet execessively fragmented, then drop */
                if (unlikely(txm->nb_segs > VMXNET3_MAX_TXD_PER_PKT)) {
@@ -365,6 +366,14 @@ vmxnet3_xmit_pkts(void *tx_queue, struct rte_mbuf 
**tx_pkts,
                        break;
                }

+               if (rte_pktmbuf_pkt_len(txm) <= VMXNET3_HDR_COPY_SIZE) {
+                       struct Vmxnet3_TxDataDesc *tdd;
+
+                       tdd = txq->data_ring.base + txq->cmd_ring.next2fill;
+                       copy_size = rte_pktmbuf_pkt_len(txm);
+                       rte_memcpy(tdd->data, rte_pktmbuf_mtod(txm, char *), 
copy_size);
+               }
+
                /* use the previous gen bit for the SOP desc */
                dw2 = (txq->cmd_ring.gen ^ 0x1) << VMXNET3_TXD_GEN_SHIFT;
                first2fill = txq->cmd_ring.next2fill;
@@ -377,7 +386,13 @@ vmxnet3_xmit_pkts(void *tx_queue, struct rte_mbuf 
**tx_pkts,
                           transmit buffer size (16K) is greater than
                           maximum sizeof mbuf segment size. */
                        gdesc = txq->cmd_ring.base + txq->cmd_ring.next2fill;
-                       gdesc->txd.addr = RTE_MBUF_DATA_DMA_ADDR(m_seg);
+                       if (copy_size)
+                               gdesc->txd.addr = 
rte_cpu_to_le_64(txq->data_ring.basePA +
+                                                               
txq->cmd_ring.next2fill *
+                                                               sizeof(struct 
Vmxnet3_TxDataDesc));
+                       else
+                               gdesc->txd.addr = RTE_MBUF_DATA_DMA_ADDR(m_seg);
+
                        gdesc->dword[2] = dw2 | m_seg->data_len;
                        gdesc->dword[3] = 0;

-- 
1.9.1

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