Re: [PATCH net v2 4/5] net: mvneta: unwind a failed mqprio setup

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi,

On 11/3/26 13:50, Josef Schlehofer wrote:
> A failed mqprio offload setup leaves part of its configuration in the
> hardware. For example, when one max_rate is not a multiple of
> 10 kbit/s, the command fails but the TX queues set up before it stay
> rate limited.
> 
> mvneta_setup_mqprio() returns on an invalid queue range or rate after
> it has already mapped RX queues, switched the rate limit mode and set
> the rates of some TX queues. The qdisc then fails to attach and the
> driver is not called again, so nothing removes them.
> 
> Undo the RX queue mapping, the rate limits and the traffic classes
> when the setup fails.
> 
> Tested on a Turris Omnia (Armada 385). After mqprio failed on a
> max_rate of 10001kbit, TX queues 0-3 stayed limited to 10 Mbit/s and
> the VLAN priority map stayed set. With this patch neither is left
> behind.
> 
> Fixes: e9f7099d0730 ("net: mvneta: Allow having more than one queue per TC")
> Fixes: 2551dc9e398c ("net: mvneta: Add TC traffic shaping offload")
> Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Maxime

> ---
>  drivers/net/ethernet/marvell/mvneta.c | 28 +++++++++++++++++++--------
>  1 file changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index 75d46349df37..d3a6bf8f383e 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -5299,8 +5299,10 @@ static int mvneta_setup_mqprio(struct net_device *dev,
>  		for (rxq = mqprio->qopt.offset[tc];
>  		     rxq < mqprio->qopt.count[tc] + mqprio->qopt.offset[tc];
>  		     rxq++) {
> -			if (rxq >= rxq_number)
> -				return -EINVAL;
> +			if (rxq >= rxq_number) {
> +				ret = -EINVAL;
> +				goto err;
> +			}
>  
>  			mvneta_map_vlan_prio_to_rxq(pp, tc, rxq);
>  		}
> @@ -5311,29 +5313,39 @@ static int mvneta_setup_mqprio(struct net_device *dev,
>  		return 0;
>  	}
>  
> -	if (mqprio->qopt.num_tc > txq_number)
> -		return -EINVAL;
> +	if (mqprio->qopt.num_tc > txq_number) {
> +		ret = -EINVAL;
> +		goto err;
> +	}
>  
>  	ret = mvneta_enable_per_queue_rate_limit(pp);
>  	if (ret)
> -		return ret;
> +		goto err;
>  
>  	for (tc = 0; tc < mqprio->qopt.num_tc; tc++) {
>  		for (txq = mqprio->qopt.offset[tc];
>  		     txq < mqprio->qopt.count[tc] + mqprio->qopt.offset[tc];
>  		     txq++) {
> -			if (txq >= txq_number)
> -				return -EINVAL;
> +			if (txq >= txq_number) {
> +				ret = -EINVAL;
> +				goto err;
> +			}
>  
>  			ret = mvneta_setup_queue_rates(pp, txq,
>  						       mqprio->min_rate[tc],
>  						       mqprio->max_rate[tc]);
>  			if (ret)
> -				return ret;
> +				goto err;
>  		}
>  	}
>  
>  	return 0;
> +
> +err:
> +	mvneta_clear_rx_prio_map(pp);
> +	mvneta_disable_per_queue_rate_limit(pp);
> +	netdev_reset_tc(dev);
> +	return ret;
>  }
>  
>  static int mvneta_setup_tc(struct net_device *dev, enum tc_setup_type type,