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

From: Lorenzo Bianconi <[email-masked]>
Date: Thu, 9 Mar 2023 09:43:34 +0100

> 
> 
> On 08/03/2023 17:47, Lorenzo Bianconi wrote:
> > > 
> > > 
> > > 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 <[email-masked]>
> > > > ---
> > > >    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?
> 
> Let's repost to net.
> It's a fixes series, and 6.3 is still in its RCs.
> If you don't post it to net then the xdp-features in 6.3 will be broken.

ack, fine.

> 
> > 
> > > Maybe it'd be better if we integrate the patches, here's my fix (still under
> > > review...):
> > > 
> > > Author: Tariq Toukan <[email-masked]>
> > > 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 <[email-masked]>
> > > 
> > > 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?
> > 
> 
> My patch doesn't replace yours, as it doesn't fix the missing
> features_update according to striding RQ and HW LRO/GRO.
> 
> I think we should combine them, either take mine as-is into your series, or
> squash it into this patch. I'm fine with both.

ack fine, I will squash your changes into the patch posting a new version, thx.

Regards,
Lorenzo

> 
> > > 
> > > 
> > > > +	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
> > 
>