Re: [PATCH net-next 7/8] net/mlx5e: take into account device reconfiguration for xdp_features flag

[Lorenzo Bianconi <lorenzo.bianconi@redhat.com>]

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> 
> 
> On 07/03/2023 16:54, Lorenzo Bianconi wrote:
> > Take into account LRO and GRO configuration setting device xdp_features
> > flag. Moreover consider channel rq_wq_type enabling rx scatter-gatter
> > support in xdp_features flag.
> > 
> > Fixes: 66c0e13ad236 ("drivers: net: turn on XDP features")
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >   drivers/net/ethernet/mellanox/mlx5/core/en.h  |  1 +
> >   .../ethernet/mellanox/mlx5/core/en_ethtool.c  | 10 ++++-
> >   .../net/ethernet/mellanox/mlx5/core/en_main.c | 45 ++++++++++++++++---
> >   .../net/ethernet/mellanox/mlx5/core/en_rep.c  |  3 ++
> >   4 files changed, 51 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
> > index 88460b7796e5..4276c6eb6820 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
> > @@ -1243,6 +1243,7 @@ void mlx5e_build_nic_params(struct mlx5e_priv *priv, struct mlx5e_xsk *xsk, u16
> >   void mlx5e_rx_dim_work(struct work_struct *work);
> >   void mlx5e_tx_dim_work(struct work_struct *work);
> > +void mlx5e_set_xdp_feature(struct net_device *netdev);
> >   netdev_features_t mlx5e_features_check(struct sk_buff *skb,
> >   				       struct net_device *netdev,
> >   				       netdev_features_t features);
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
> > index 7708acc9b2ab..79fd21ecb9cb 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
> > @@ -1985,6 +1985,7 @@ static int set_pflag_rx_striding_rq(struct net_device *netdev, bool enable)
> >   	struct mlx5e_priv *priv = netdev_priv(netdev);
> >   	struct mlx5_core_dev *mdev = priv->mdev;
> >   	struct mlx5e_params new_params;
> > +	int err;
> >   	if (enable) {
> >   		/* Checking the regular RQ here; mlx5e_validate_xsk_param called
> > @@ -2005,7 +2006,14 @@ static int set_pflag_rx_striding_rq(struct net_device *netdev, bool enable)
> >   	MLX5E_SET_PFLAG(&new_params, MLX5E_PFLAG_RX_STRIDING_RQ, enable);
> >   	mlx5e_set_rq_type(mdev, &new_params);
> > -	return mlx5e_safe_switch_params(priv, &new_params, NULL, NULL, true);
> > +	err = mlx5e_safe_switch_params(priv, &new_params, NULL, NULL, true);
> > +	if (err)
> > +		return err;
> > +
> > +	/* update XDP supported features */
> > +	mlx5e_set_xdp_feature(netdev);
> > +
> > +	return 0;
> >   }
> >   static int set_pflag_rx_no_csum_complete(struct net_device *netdev, bool enable)
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > index 76a9c5194a70..1b68dd2be2c5 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> > @@ -4004,6 +4004,30 @@ static int mlx5e_handle_feature(struct net_device *netdev,
> >   	return 0;
> >   }
> > +void mlx5e_set_xdp_feature(struct net_device *netdev)
> > +{
> > +	struct mlx5e_priv *priv = netdev_priv(netdev);
> > +	bool ndo_xmit = test_bit(MLX5E_STATE_XDP_ACTIVE, &priv->state);
> 
> Our driver doesn't require loading a dummy XDP program to have the
> redirect-in ability. It's always there.
> 
> I actually have a bug fix under internal review with Saeed that addresses
> this.
> 
> In addition, it cleans up the NETDEV_XDP_ACT_NDO_XMIT_SG as we do not
> support it yet. I have a series that's adding support and will submit it
> soon.
> 
> Any reason you're submitting these fixes to net-next rather than net?

Hi Tariq,

I am fine to repost this series for net instead of net-next. Any downsides about
it?

> Maybe it'd be better if we integrate the patches, here's my fix (still under
> review...):
> 
> Author: Tariq Toukan <tariqt@nvidia.com>
> Date:   Thu Feb 23 08:58:04 2023 +0200
> 
>     net/mlx5e: Fix exposed xdp_features
> 
>     Always declare NETDEV_XDP_ACT_NDO_XMIT as the ndo_xdp_xmit callback
>     is always functional per our design, and does not require loading
>     a dummy xdp program.
> 
>     Although non-linear XDP buffer is supported for XDP_TX flow, do not
>     declare NETDEV_XDP_ACT_NDO_XMIT_SG as it is yet supported for
>     redirected-in frames.
> 
>     Fixes: 66c0e13ad236 ("drivers: net: turn on XDP features")
>     Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> index 53feb0529943..9a5d3ce1fbcd 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> @@ -4741,13 +4741,6 @@ static int mlx5e_xdp_set(struct net_device *netdev,
> struct bpf_prog *prog)
>         if (old_prog)
>                 bpf_prog_put(old_prog);
> 
> -       if (reset) {
> -               if (prog)
> -                       xdp_features_set_redirect_target(netdev, true);
> -               else
> -                       xdp_features_clear_redirect_target(netdev);
> -       }
> -
>         if (!test_bit(MLX5E_STATE_OPENED, &priv->state) || reset)
>                 goto unlock;
> 
> @@ -5144,6 +5137,7 @@ static void mlx5e_build_nic_netdev(struct net_device
> *netdev)
>         netdev->features         |= NETIF_F_HW_VLAN_STAG_FILTER;
> 
>         netdev->xdp_features = NETDEV_XDP_ACT_BASIC |
> NETDEV_XDP_ACT_REDIRECT |
> +                              NETDEV_XDP_ACT_NDO_XMIT |
>                                NETDEV_XDP_ACT_XSK_ZEROCOPY |
>                                NETDEV_XDP_ACT_RX_SG;

I am fine to drop this my patch and rely on the one you provided but it depends
on the eta about the described patches because otherwise real capabilities and
xdp-features will not be aligned. Any inputs on it?

> 
> 
> > +	struct mlx5e_params *params = &priv->channels.params;
> > +	xdp_features_t val;
> > +
> > +	if (params->packet_merge.type != MLX5E_PACKET_MERGE_NONE) {
> > +		xdp_clear_features_flag(netdev);
> > +		return;
> > +	}
> > +
> > +	val = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
> > +	      NETDEV_XDP_ACT_XSK_ZEROCOPY;
> > +	if (ndo_xmit)
> > +		val |= NETDEV_XDP_ACT_NDO_XMIT;
> > +	if (params->rq_wq_type == MLX5_WQ_TYPE_CYCLIC) {
> > +		val |= NETDEV_XDP_ACT_RX_SG;
> > +		if (ndo_xmit)
> > +			val |= NETDEV_XDP_ACT_NDO_XMIT_SG;
> 
> This NETDEV_XDP_ACT_NDO_XMIT_SG capability is not related to the RQ type.
> It's still not supported at this point.

ack, I will fix it.

> 
> BTW, I have a series completing all the missing capabilities (multibuf on
> Striding + multibuf redirect-in), should be submitted in this kernel.

cool :)

Regards,
Lorenzo

> 
> > +	}
> > +	xdp_set_features_flag(netdev, val);
> > +}
> > +
> >   int mlx5e_set_features(struct net_device *netdev, netdev_features_t features)
> >   {
> >   	netdev_features_t oper_features = features;
> > @@ -4030,6 +4054,9 @@ int mlx5e_set_features(struct net_device *netdev, netdev_features_t features)
> >   		return -EINVAL;
> >   	}
> > +	/* update XDP supported features */
> > +	mlx5e_set_xdp_feature(netdev);
> > +
> >   	return 0;
> >   }
> > @@ -4762,10 +4789,14 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)
> >   		bpf_prog_put(old_prog);
> >   	if (reset) {
> > -		if (prog)
> > -			xdp_features_set_redirect_target(netdev, true);
> > -		else
> > +		if (prog) {
> > +			bool xmit_sg;
> > +
> > +			xmit_sg = new_params.rq_wq_type == MLX5_WQ_TYPE_CYCLIC;
> 
> Same, not related. Still not supported at this point.
> 
> > +			xdp_features_set_redirect_target(netdev, xmit_sg);
> > +		} else {
> >   			xdp_features_clear_redirect_target(netdev);
> > +		}
> >   	}
> >   	if (!test_bit(MLX5E_STATE_OPENED, &priv->state) || reset)
> > @@ -5163,13 +5194,10 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)
> >   	netdev->features         |= NETIF_F_HIGHDMA;
> >   	netdev->features         |= NETIF_F_HW_VLAN_STAG_FILTER;
> > -	netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
> > -			       NETDEV_XDP_ACT_XSK_ZEROCOPY |
> > -			       NETDEV_XDP_ACT_RX_SG;
> > -
> >   	netdev->priv_flags       |= IFF_UNICAST_FLT;
> >   	netif_set_tso_max_size(netdev, GSO_MAX_SIZE);
> > +	mlx5e_set_xdp_feature(netdev);
> >   	mlx5e_set_netdev_dev_addr(netdev);
> >   	mlx5e_macsec_build_netdev(priv);
> >   	mlx5e_ipsec_build_netdev(priv);
> > @@ -5241,6 +5269,9 @@ static int mlx5e_nic_init(struct mlx5_core_dev *mdev,
> >   		mlx5_core_err(mdev, "TLS initialization failed, %d\n", err);
> >   	mlx5e_health_create_reporters(priv);
> > +	/* update XDP supported features */
> > +	mlx5e_set_xdp_feature(netdev);
> > +
> >   	return 0;
> >   }
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
> > index 9b9203443085..43fd12fb87b8 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
> > @@ -747,6 +747,9 @@ static void mlx5e_build_rep_params(struct net_device *netdev)
> >   	/* RQ */
> >   	mlx5e_build_rq_params(mdev, params);
> > +	/* update XDP supported features */
> > +	mlx5e_set_xdp_feature(netdev);
> > +
> >   	/* CQ moderation params */
> >   	params->rx_dim_enabled = MLX5_CAP_GEN(mdev, cq_moderation);
> >   	mlx5e_set_rx_cq_mode_params(params, cq_period_mode);
> 

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