Re: [patch net-next v2 14/15] devlink: move port_del() to devlink_port_ops

[Jakub Kicinski <kuba@kernel.org>]

On Mon, 29 May 2023 10:31:14 +0200 Jiri Pirko wrote:
> >One could argue logically removing a port is also an operation of 
> >the parent (i.e. the devlink instance). The fact that the port gets
> >destroyed in the process is secondary. Ergo maybe we should skip 
> >this patch?  
> 
> Well, the port_del() could differ for different port flavours. The
> embedding structure of struct devlink_port is also different.
> 
> Makes sense to me to skip the flavour switch and have one port_del() for
> each port.

The asymmetry bothers me. It's hard to comment on what the best
approach is given this series shows no benefit of moving port_del().
Maybe even a loss, as mlx5 now has an ifdef in two places:

> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
> index e39fd85ea2f9..63635cc44479 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
> @@ -320,7 +320,6 @@ static const struct devlink_ops mlx5_devlink_ops = {
>  #endif
>  #ifdef CONFIG_MLX5_SF_MANAGER
>  	.port_new = mlx5_devlink_sf_port_new,
> -	.port_del = mlx5_devlink_sf_port_del,
>  #endif
>  	.flash_update = mlx5_devlink_flash_update,
>  	.info_get = mlx5_devlink_info_get,
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c
> index 76c5d6e9d47f..f370f67d9e33 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/devlink_port.c
> @@ -145,6 +145,9 @@ struct devlink_port *mlx5_esw_offloads_devlink_port(struct mlx5_eswitch *esw, u1
>  }
>  
>  static const struct devlink_port_ops mlx5_esw_dl_sf_port_ops = {
> +#ifdef CONFIG_MLX5_SF_MANAGER
> +	.port_del = mlx5_devlink_sf_port_del,
> +#endif
>  	.port_fn_hw_addr_get = mlx5_devlink_port_fn_hw_addr_get,
>  	.port_fn_hw_addr_set = mlx5_devlink_port_fn_hw_addr_set,
>  	.port_fn_roce_get = mlx5_devlink_port_fn_roce_get,

Is it okay if we deferred the port_del() patch until there's some
clear benefit?