On Thu, Nov 21, 2019 at 10:36:36PM -0300, Julio Faracco wrote:
> Driver virtio_net is not handling error events for TX provided by
> dev_watchdog. This event is reached when transmission queue is having
> problems to transmit packets. This could happen for any reason. To
> enable it, driver should have .ndo_tx_timeout implemented.
>
> This commit brings back virtnet_reset method to recover TX queues from a
> error state. That function is called by schedule_work method and it puts
> the reset function into work queue.
>
> As the error cause is unknown at this moment, it would be better to
> reset all queues.
>
> Signed-off-by: Julio Faracco <jcfaracco@xxxxxxxxx>
> Signed-off-by: Daiane Mendes <dnmendes76@xxxxxxxxx>
> Cc: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> v1-v2: Tag `net-next` was included to indentify where patch would be
> applied.
> ---
> drivers/net/virtio_net.c | 95 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 94 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 4d7d5434cc5d..31890d77eaf2 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -75,6 +75,7 @@ struct virtnet_sq_stats {
> u64 xdp_tx;
> u64 xdp_tx_drops;
> u64 kicks;
> + u64 tx_timeouts;
> };
>
> struct virtnet_rq_stats {
> @@ -98,6 +99,7 @@ static const struct virtnet_stat_desc virtnet_sq_stats_desc[] = {
> { "xdp_tx", VIRTNET_SQ_STAT(xdp_tx) },
> { "xdp_tx_drops", VIRTNET_SQ_STAT(xdp_tx_drops) },
> { "kicks", VIRTNET_SQ_STAT(kicks) },
> + { "tx_timeouts", VIRTNET_SQ_STAT(tx_timeouts) },
> };
>
> static const struct virtnet_stat_desc virtnet_rq_stats_desc[] = {
> @@ -211,6 +213,9 @@ struct virtnet_info {
> /* Work struct for config space updates */
> struct work_struct config_work;
>
> + /* Work struct for resetting the virtio-net driver. */
> + struct work_struct reset_work;
> +
> /* Does the affinity hint is set for virtqueues? */
> bool affinity_hint_set;
>
> @@ -1721,7 +1726,7 @@ static void virtnet_stats(struct net_device *dev,
> int i;
>
> for (i = 0; i < vi->max_queue_pairs; i++) {
> - u64 tpackets, tbytes, rpackets, rbytes, rdrops;
> + u64 tpackets, tbytes, terrors, rpackets, rbytes, rdrops;
> struct receive_queue *rq = &vi->rq[i];
> struct send_queue *sq = &vi->sq[i];
>
> @@ -1729,6 +1734,7 @@ static void virtnet_stats(struct net_device *dev,
> start = u64_stats_fetch_begin_irq(&sq->stats.syncp);
> tpackets = sq->stats.packets;
> tbytes = sq->stats.bytes;
> + terrors = sq->stats.tx_timeouts;
> } while (u64_stats_fetch_retry_irq(&sq->stats.syncp, start));
>
> do {
> @@ -1743,6 +1749,7 @@ static void virtnet_stats(struct net_device *dev,
> tot->rx_bytes += rbytes;
> tot->tx_bytes += tbytes;
> tot->rx_dropped += rdrops;
> + tot->tx_errors += terrors;
> }
>
> tot->tx_dropped = dev->stats.tx_dropped;
> @@ -2578,6 +2585,33 @@ static int virtnet_set_features(struct net_device *dev,
> return 0;
> }
>
> +static void virtnet_tx_timeout(struct net_device *dev)
> +{
> + struct virtnet_info *vi = netdev_priv(dev);
> + u32 i;
> +
> + netdev_warn(dev, "TX timeout stats:\n");
> + /* find the stopped queue the same way dev_watchdog() does */
> + for (i = 0; i < vi->curr_queue_pairs; i++) {
> + struct send_queue *sq = &vi->sq[i];
> +
> + if (!netif_xmit_stopped(netdev_get_tx_queue(dev, i))) {
> + netdev_warn(dev, " Available send queue: %d, sq: %s, vq: %d, name: %s\n",
> + i, sq->name, sq->vq->index, sq->vq->name);
What does this mean?
> + continue;
> + }
> +
> + u64_stats_update_begin(&sq->stats.syncp);
> + sq->stats.tx_timeouts++;
> + u64_stats_update_end(&sq->stats.syncp);
> +
> + netdev_warn(dev, " Unavailable send queue: %d, sq: %s, vq: %d, name: %s\n",
> + i, sq->name, sq->vq->index, sq->vq->name);
> + }
Can we make the warning less cryptic?
I wonder why don't we get the sq from timeout directly?
Would seem cleaner.
> +
> + schedule_work(&vi->reset_work);
> +}
> +
> static const struct net_device_ops virtnet_netdev = {
> .ndo_open = virtnet_open,
> .ndo_stop = virtnet_close,
> @@ -2593,6 +2627,7 @@ static const struct net_device_ops virtnet_netdev = {
> .ndo_features_check = passthru_features_check,
> .ndo_get_phys_port_name = virtnet_get_phys_port_name,
> .ndo_set_features = virtnet_set_features,
> + .ndo_tx_timeout = virtnet_tx_timeout,
> };
>
> static void virtnet_config_changed_work(struct work_struct *work)
> @@ -2982,6 +3017,62 @@ static int virtnet_validate(struct virtio_device *vdev)
> return 0;
> }
>
> +static void _remove_vq_common(struct virtnet_info *vi)
> +{
> + vi->vdev->config->reset(vi->vdev);
> +
> + /* Free unused buffers in both send and recv, if any. */
> + free_unused_bufs(vi);
> +
> + _free_receive_bufs(vi);
> +
> + free_receive_page_frags(vi);
> +
> + virtnet_del_vqs(vi);
> +}
> +
> +static int _virtnet_reset(struct virtnet_info *vi)
> +{
> + struct virtio_device *vdev = vi->vdev;
> + int ret;
> +
> + virtio_config_disable(vdev);
> + vdev->failed = vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_FAILED;
> +
> + virtnet_freeze_down(vdev);
> + _remove_vq_common(vi);
> +
> + virtio_add_status(vdev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
> + virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER);
> +
> + ret = virtio_finalize_features(vdev);
> + if (ret)
> + goto err;
> +
> + ret = virtnet_restore_up(vdev);
> + if (ret)
> + goto err;
> +
> + ret = _virtnet_set_queues(vi, vi->curr_queue_pairs);
> + if (ret)
> + goto err;
> +
> + virtio_add_status(vdev, VIRTIO_CONFIG_S_DRIVER_OK);
> + virtio_config_enable(vdev);
Is this enough? E.g. all RX mode programming has been lost.
> + return 0;
> +err:
> + virtio_add_status(vdev, VIRTIO_CONFIG_S_FAILED);
> + return ret;
> +}
> +
> +static void virtnet_reset(struct work_struct *work)
> +{
> + struct virtnet_info *vi =
> + container_of(work, struct virtnet_info, reset_work);
> +
> + _virtnet_reset(vi);
> +}
> +
> static int virtnet_probe(struct virtio_device *vdev)
> {
> int i, err = -ENOMEM;
> @@ -3011,6 +3102,7 @@ static int virtnet_probe(struct virtio_device *vdev)
> dev->netdev_ops = &virtnet_netdev;
> dev->features = NETIF_F_HIGHDMA;
>
> + dev->watchdog_timeo = 5 * HZ;
> dev->ethtool_ops = &virtnet_ethtool_ops;
> SET_NETDEV_DEV(dev, &vdev->dev);
>
Is there a way to make this tuneable from ethtool?
> @@ -3068,6 +3160,7 @@ static int virtnet_probe(struct virtio_device *vdev)
> vdev->priv = vi;
>
> INIT_WORK(&vi->config_work, virtnet_config_changed_work);
> + INIT_WORK(&vi->reset_work, virtnet_reset);
>
> /* If we can receive ANY GSO packets, we must allocate large ones. */
> if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
> --
> 2.17.1
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