Re: [dpdk-dev] [PATCH] net/failsafe: fix source port ID in Rx packets

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

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On Thu, Apr 18, 2019 at 03:11:26PM +0200, Adrien Mazarguil wrote:
> When passed to the application, Rx packets retain the port ID value
> originally set by slave devices. Unfortunately these IDs have no meaning to
> applications, which are typically unaware of their existence.
> 
> This confuses those caring about the source port field in mbufs (m->port)
> which experience issues ranging from traffic drop to crashes.
> 
> Fixes: a46f8d584eb8 ("net/failsafe: add fail-safe PMD")
> Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>

Missing a Cc: stable@dpdk.org no? Given that no one saw that until a
slightly heavier application was used with the fail-safe, I guess few
people will care, but still.

Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>

> ---
>  drivers/net/failsafe/failsafe_rxtx.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/net/failsafe/failsafe_rxtx.c b/drivers/net/failsafe/failsafe_rxtx.c
> index 231c83291..e78624127 100644
> --- a/drivers/net/failsafe/failsafe_rxtx.c
> +++ b/drivers/net/failsafe/failsafe_rxtx.c
> @@ -61,6 +61,21 @@ failsafe_set_burst_fn(struct rte_eth_dev *dev, int force_safe)
>  	rte_wmb();
>  }
>  
> +/*
> + * Override source port in Rx packets.
> + *
> + * Make Rx packets originate from this PMD instance instead of one of its
> + * slaves. This is mandatory to avoid breaking applications.
> + */
> +static void
> +failsafe_rx_set_port(struct rte_mbuf **rx_pkts, uint16_t nb_pkts, uint16_t port)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i != nb_pkts; ++i)
> +		rx_pkts[i]->port = port;
> +}
> +
>  uint16_t
>  failsafe_rx_burst(void *queue,
>  		  struct rte_mbuf **rx_pkts,
> @@ -87,6 +102,9 @@ failsafe_rx_burst(void *queue,
>  		sdev = sdev->next;
>  	} while (nb_rx == 0 && sdev != rxq->sdev);
>  	rxq->sdev = sdev;
> +	if (nb_rx)
> +		failsafe_rx_set_port(rx_pkts, nb_rx,
> +				     rxq->priv->dev->data->port_id);
>  	return nb_rx;
>  }
>  
> @@ -112,6 +130,9 @@ failsafe_rx_burst_fast(void *queue,
>  		sdev = sdev->next;
>  	} while (nb_rx == 0 && sdev != rxq->sdev);
>  	rxq->sdev = sdev;
> +	if (nb_rx)
> +		failsafe_rx_set_port(rx_pkts, nb_rx,
> +				     rxq->priv->dev->data->port_id);
>  	return nb_rx;
>  }
>  
> -- 
> 2.11.0

-- 
Gaëtan Rivet
6WIND