[dpdk-stable] [PATCH] net/mlx5: fix rss reta is reset when device is started

[Maxime Leroy]

Hi Raslan,

Any comment/review on the fix ?

Regards,

Maxime

On Thu, Jul 16, 2020 at 12:43 PM Maxime Leroy <maxime.leroy at 6wind.com> wrote:
>
> The following sequences was working fine on mlx5:
>    rte_eth_dev_configure(portid, ...);
>
>    for (queueid = 0; queueid < nb_txq; queueid++)
>       rte_eth_tx_queue_setup(portid, queueid, ...);
>
>    for (queueid = 0; queueid < nb_rxq; queueid++)
>       rte_eth_rx_queue_setup(portid, queueid, ...);
>
>   // use a custom reta configuration
>   rte_eth_dev_rss_reta_update(portid, reta_conf, reta_size);
>   rte_eth_dev_start(portid);
>
> We were able to configure a custom reta before starting the port.
>
> The commit "net/mlx5: support RSS on hairpin" breaks this logic by
> moving the code initializing the RSS reta from rte_eth_dev_configure
> into rte_eth_dev_start.
>
> To fix the issue, the skip_default_rss_reta is always set to 1 in
> rte_eth_dev_rss_reta to avoid reconfigure the rss reta when the device
> is started.
>
> Fixes: 63bd16292c3a ("net/mlx5: support RSS on hairpin")
> Signed-off-by: Maxime Leroy <maxime.leroy at 6wind.com>
> ---
>  drivers/net/mlx5/mlx5_rss.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/mlx5/mlx5_rss.c b/drivers/net/mlx5/mlx5_rss.c
> index 653b0691..6f75ece2 100644
> --- a/drivers/net/mlx5/mlx5_rss.c
> +++ b/drivers/net/mlx5/mlx5_rss.c
> @@ -220,9 +220,11 @@ mlx5_dev_rss_reta_update(struct rte_eth_dev *dev,
>                 MLX5_ASSERT(reta_conf[idx].reta[pos] < priv->rxqs_n);
>                 (*priv->reta_idx)[i] = reta_conf[idx].reta[pos];
>         }
> +
> +       priv->skip_default_rss_reta = 1;
> +
>         if (dev->data->dev_started) {
>                 mlx5_dev_stop(dev);
> -               priv->skip_default_rss_reta = 1;
>                 return mlx5_dev_start(dev);
>         }
>         return 0;
> --
> 2.27.0
>