Re: [dpdk-dev] [dpdk-stable] [PATCH v2 1/4] net/virtio: fix segmented packet issue in in-order Rx path

[David Marchand <david.marchand@redhat.com>]

On Wed, Jun 5, 2019 at 10:10 AM Maxime Coquelin <maxime.coquelin@redhat.com>
wrote:

> After having dequeued a burst of descriptors, there may be a
> need to dequeue a few more if the last packet was segmented
> and not complete. When it happens, the extra segments were
> not properly attached to the mbuf chain, and so were lost.
>
> Also, head segment data_len field is wrongly summed with
> the length of all the segments of the chain.
>
> This patch fixes both the mbuf chaining and head segment's
> data_len field.
>
> Fixes: e5f456a98d3c ("net/virtio: support in-order Rx and Tx")
> Cc: stable@dpdk.org
>
> Reported-by: Yaroslav Brustinov <ybrustin@cisco.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  drivers/net/virtio/virtio_rxtx.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> index 1de28540cd..6b3baf0423 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -1424,7 +1424,7 @@ virtio_recv_pkts_inorder(void *rx_queue,
>         struct virtqueue *vq = rxvq->vq;
>         struct virtio_hw *hw = vq->hw;
>         struct rte_mbuf *rxm;
> -       struct rte_mbuf *prev;
> +       struct rte_mbuf *prev = NULL;
>         uint16_t nb_used, num, nb_rx;
>         uint32_t len[VIRTIO_MBUF_BURST_SZ];
>         struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
> @@ -1516,7 +1516,6 @@ virtio_recv_pkts_inorder(void *rx_queue,
>                         rxm->data_len = (uint16_t)(len[i]);
>
>                         rx_pkts[nb_rx]->pkt_len += (uint32_t)(len[i]);
> -                       rx_pkts[nb_rx]->data_len += (uint16_t)(len[i]);
>
>                         if (prev)
>                                 prev->next = rxm;
> @@ -1536,7 +1535,6 @@ virtio_recv_pkts_inorder(void *rx_queue,
>                 uint16_t rcv_cnt = RTE_MIN((uint16_t)seg_res,
>                                         VIRTIO_MBUF_BURST_SZ);
>
> -               prev = rcv_pkts[nb_rx];
>                 if (likely(VIRTQUEUE_NUSED(vq) >= rcv_cnt)) {
>                         virtio_rmb(hw->weak_barriers);
>                         num = virtqueue_dequeue_rx_inorder(vq, rcv_pkts,
> len,
>

I think you have missed another data_len update line 1554.

Reviewed-by: David Marchand <david.marchand@redhat.com>


-- 
David Marchand