On Mon, Dec 04, 2017 at 06:02:08AM -0800, Xiao Wang wrote:
[...]
> diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> index 6a24fde..7313bdd 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -1100,3 +1100,84 @@
>
> return nb_tx;
> }
> +
> +uint16_t
> +virtio_inject_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t
> nb_pkts)
> +{
> + struct virtnet_tx *txvq = tx_queue;
> + struct virtqueue *vq = txvq->vq;
> + struct virtio_hw *hw = vq->hw;
> + uint16_t hdr_size = hw->vtnet_hdr_size;
> + uint16_t nb_used, nb_tx = 0;
> +
> + if (unlikely(nb_pkts < 1))
> + return nb_pkts;
> +
> + PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts);
> + nb_used = VIRTQUEUE_NUSED(vq);
> +
> + virtio_rmb();
> + if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh))
> + virtio_xmit_cleanup(vq, nb_used);
> +
> + for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
> + struct rte_mbuf *txm = tx_pkts[nb_tx];
> + int can_push = 0, use_indirect = 0, slots, need;
> +
> + /* optimize ring usage */
> + if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
> + vtpci_with_feature(hw,
> VIRTIO_F_VERSION_1)) &&
> + rte_mbuf_refcnt_read(txm) == 1 &&
> + RTE_MBUF_DIRECT(txm) &&
> + txm->nb_segs == 1 &&
> + rte_pktmbuf_headroom(txm) >= hdr_size &&
> + rte_is_aligned(rte_pktmbuf_mtod(txm, char *),
> + __alignof__(struct virtio_net_hdr_mrg_rxbuf)))
> + can_push = 1;
> + else if (vtpci_with_feature(hw, VIRTIO_RING_F_INDIRECT_DESC) &&
> + txm->nb_segs < VIRTIO_MAX_TX_INDIRECT)
> + use_indirect = 1;
> +
> + /* How many main ring entries are needed to this Tx?
> + * any_layout => number of segments
> + * indirect => 1
> + * default => number of segments + 1
> + */
> + slots = use_indirect ? 1 : (txm->nb_segs + !can_push);
> + need = slots - vq->vq_free_cnt;
> +
> + /* Positive value indicates it need free vring descriptors */
> + if (unlikely(need > 0)) {
> + nb_used = VIRTQUEUE_NUSED(vq);
> + virtio_rmb();
> + need = RTE_MIN(need, (int)nb_used);
> +
> + virtio_xmit_cleanup(vq, need);
> + need = slots - vq->vq_free_cnt;
> + if (unlikely(need > 0)) {
> + PMD_TX_LOG(ERR,
> + "No free tx descriptors to
> transmit");
> + break;
> + }
> + }
> +
> + /* Enqueue Packet buffers */
> + virtqueue_enqueue_xmit(txvq, txm, slots, use_indirect,
> can_push);
> +
> + txvq->stats.bytes += txm->pkt_len;
> + virtio_update_packet_stats(&txvq->stats, txm);
> + }
> +
> + txvq->stats.packets += nb_tx;
> +
> + if (likely(nb_tx)) {
> + vq_update_avail_idx(vq);
> +
> + if (unlikely(virtqueue_kick_prepare(vq))) {
> + virtqueue_notify(vq);
> + PMD_TX_LOG(DEBUG, "Notified backend after xmit");
> + }
> + }
> +
> + return nb_tx;
> +}
Simple Tx has some special assumptions and setups of the txq.
Basically the current implementation of virtio_inject_pkts()
is a mirror of virtio_xmit_pkts(). So when simple Tx function
is chosen, calling virtio_inject_pkts() could cause problems.
Best regards,
Tiwei Bie
