Subject: Re: [PATCH net-next v5 2/2] net/mlx5e: add mlx5e_rep_indr_setup_ft_cb support

From: Vlad Buslov <[email-masked]>
Date: Tue, 24 Mar 2020 16:36:16 +0200

On Tue 24 Mar 2020 at 14:49, wenxu <[email-masked]> wrote:
> 在 2020/3/24 20:05, Vlad Buslov 写道:
>> On Tue 24 Mar 2020 at 01:44, [email-masked] wrote:
>>> From: wenxu <[email-masked]>
>>>
>>> Add mlx5e_rep_indr_setup_ft_cb to support indr block setup
>>> in FT mode.
>>>
>>> Signed-off-by: wenxu <[email-masked]>
>>> ---
>>> v5: no change
>>>
>>>   drivers/net/ethernet/mellanox/mlx5/core/en_rep.c | 52 ++++++++++++++++++++++++
>>>   1 file changed, 52 insertions(+)
>>>
>>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
>>> index 057f5f9..30c81c3 100644
>>> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
>>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
>>> @@ -732,6 +732,55 @@ static int mlx5e_rep_indr_setup_tc_cb(enum tc_setup_type type,
>>>   	}
>>>   }
>>>
>>> +static int mlx5e_rep_indr_setup_ft_cb(enum tc_setup_type type,
>>> +				      void *type_data, void *indr_priv)
>>> +{
>>> +	struct mlx5e_rep_indr_block_priv *priv = indr_priv;
>>> +	struct flow_cls_offload *f = type_data;
>>> +	struct flow_cls_offload tmp;
>>> +	struct mlx5e_priv *mpriv;
>>> +	struct mlx5_eswitch *esw;
>>> +	unsigned long flags;
>>> +	int err;
>>> +
>>> +	mpriv = netdev_priv(priv->rpriv->netdev);
>>> +	esw = mpriv->mdev->priv.eswitch;
>>> +
>>> +	flags = MLX5_TC_FLAG(EGRESS) |
>>> +		MLX5_TC_FLAG(ESW_OFFLOAD) |
>>> +		MLX5_TC_FLAG(FT_OFFLOAD);
>>> +
>>> +	switch (type) {
>>> +	case TC_SETUP_CLSFLOWER:
>>> +		memcpy(&tmp, f, sizeof(*f));
>>> +
>>> +		if (!mlx5_esw_chains_prios_supported(esw))
>>> +			return -EOPNOTSUPP;
>>> +
>>> +		/* Re-use tc offload path by moving the ft flow to the
>>> +		 * reserved ft chain.
>>> +		 *
>>> +		 * FT offload can use prio range [0, INT_MAX], so we normalize
>>> +		 * it to range [1, mlx5_esw_chains_get_prio_range(esw)]
>>> +		 * as with tc, where prio 0 isn't supported.
>>> +		 *
>>> +		 * We only support chain 0 of FT offload.
>>> +		 */
>>> +		if (tmp.common.prio >= mlx5_esw_chains_get_prio_range(esw))
>>> +			return -EOPNOTSUPP;
>>> +		if (tmp.common.chain_index != 0)
>>> +			return -EOPNOTSUPP;
>>> +
>>> +		tmp.common.chain_index = mlx5_esw_chains_get_ft_chain(esw);
>>> +		tmp.common.prio++;
>>> +		err = mlx5e_rep_indr_offload(priv->netdev, &tmp, priv, flags);
>>> +		memcpy(&f->stats, &tmp.stats, sizeof(f->stats));
>> Why do you need to create temporary copy of flow_cls_offload struct and
>> then copy parts of tmp back to the original? Again, this info should
>> probably be in the commit message.
>
> This FT mode using the specficed chain_index which changed by driver adnd
>
> using only in driver. It will move the flow table rules to their steering
> domain.
>
> This scenario just follow the mlx5e_rep_setup_ft_cb which did offload in FT
> mode.
>
> So it's an old scenario, Is it necessary to add to the commit message?

Well, without knowing the reasoning it is hard to understand if the
original scenario is applicable in this case.

>
>>
>>> +		return err;
>>> +	default:
>>> +		return -EOPNOTSUPP;
>>> +	}
>>> +}
>>> +
>>>   static void mlx5e_rep_indr_block_unbind(void *cb_priv)
>>>   {
>>>   	struct mlx5e_rep_indr_block_priv *indr_priv = cb_priv;
>>> @@ -809,6 +858,9 @@ int mlx5e_rep_indr_setup_cb(struct net_device *netdev, void *cb_priv,
>>>   	case TC_SETUP_BLOCK:
>>>   		return mlx5e_rep_indr_setup_block(netdev, cb_priv, type_data,
>>>   						  mlx5e_rep_indr_setup_tc_cb);
>>> +	case TC_SETUP_FT:
>>> +		return mlx5e_rep_indr_setup_block(netdev, cb_priv, type_data,
>>> +						  mlx5e_rep_indr_setup_ft_cb);
>>>   	default:
>>>   		return -EOPNOTSUPP;
>>>   	}