[PATCH v2 2/2] vhost: fix slot index calculation in async vhost
Maxime Coquelin
maxime.coquelin at redhat.com
Fri Oct 21 10:17:07 CEST 2022
On 10/11/22 05:08, Cheng Jiang wrote:
> When the packet receiving failure and the DMA ring full occur
> simultaneously in the asynchronous vhost, the slot_idx needs to be
> decreased by 1. For packed virtqueue, the slot index should be
> ring_size - 1, if the slot_idx is currently 0, since the ring size is
> not necessarily the power of 2.
>
> Fixes: 84d5204310d7 ("vhost: support async dequeue for split ring")
> Fixes: fe8477ebbd94 ("vhost: support async packed ring dequeue")
> Cc: stable at dpdk.org
>
> Signed-off-by: Cheng Jiang <cheng1.jiang at intel.com>
> ---
> lib/vhost/virtio_net.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 457ac2e92a..efebd063d7 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -3457,6 +3457,7 @@ virtio_dev_tx_async_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
> allocerr_warned = true;
> }
> dropped = true;
> + slot_idx--;
> break;
> }
>
> @@ -3647,6 +3648,12 @@ virtio_dev_tx_async_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
> if (unlikely(virtio_dev_tx_async_single_packed(dev, vq, mbuf_pool, pkt,
> slot_idx, legacy_ol_flags))) {
> rte_pktmbuf_free_bulk(&pkts_prealloc[pkt_idx], count - pkt_idx);
> +
> + if (slot_idx == 0)
> + slot_idx = vq->size - 1;
> + else
> + slot_idx--;
> +
> break;
> }
>
> @@ -3674,8 +3681,13 @@ virtio_dev_tx_async_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
> async->buffer_idx_packed += vq->size - pkt_err;
>
> while (pkt_err-- > 0) {
> - rte_pktmbuf_free(pkts_info[slot_idx % vq->size].mbuf);
> - slot_idx--;
> + rte_pktmbuf_free(pkts_info[slot_idx].mbuf);
> + descs_err += pkts_info[slot_idx].descs;
> +
> + if (slot_idx == 0)
> + slot_idx = vq->size - 1;
> + else
> + slot_idx--;
> }
>
> /* recover available ring */
Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
Thanks,
Maxime
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