Re: [PATCH net-next 12/16] idpf: implement XDP_SETUP_PROG in ndo_bpf for splitq

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

On Wed, Mar 05, 2025 at 05:21:28PM +0100, Alexander Lobakin wrote:
> From: Michal Kubiak <michal.kubiak@intel.com>
> 
> Implement loading/removing XDP program using .ndo_bpf callback
> in the split queue mode. Reconfigure and restart the queues if needed
> (!!old_prog != !!new_prog), otherwise, just update the pointers.
> 
> Signed-off-by: Michal Kubiak <michal.kubiak@intel.com>
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
> ---
>  drivers/net/ethernet/intel/idpf/idpf_txrx.h |   4 +-
>  drivers/net/ethernet/intel/idpf/xdp.h       |   7 ++
>  drivers/net/ethernet/intel/idpf/idpf_lib.c  |   1 +
>  drivers/net/ethernet/intel/idpf/idpf_txrx.c |   4 +
>  drivers/net/ethernet/intel/idpf/xdp.c       | 114 ++++++++++++++++++++
>  5 files changed, 129 insertions(+), 1 deletion(-)
> 

(...)

> +
> +/**
> + * idpf_xdp_setup_prog - handle XDP program install/remove requests
> + * @vport: vport to configure
> + * @xdp: request data (program, extack)
> + *
> + * Return: 0 on success, -errno on failure.
> + */
> +static int
> +idpf_xdp_setup_prog(struct idpf_vport *vport, const struct netdev_bpf *xdp)
> +{
> +	const struct idpf_netdev_priv *np = netdev_priv(vport->netdev);
> +	struct bpf_prog *old, *prog = xdp->prog;
> +	struct idpf_vport_config *cfg;
> +	int ret;
> +
> +	cfg = vport->adapter->vport_config[vport->idx];
> +	if (!vport->num_xdp_txq && vport->num_txq == cfg->max_q.max_txq) {
> +		NL_SET_ERR_MSG_MOD(xdp->extack,
> +				   "No Tx queues available for XDP, please decrease the number of regular SQs");
> +		return -ENOSPC;
> +	}
> +
> +	if (test_bit(IDPF_REMOVE_IN_PROG, vport->adapter->flags) ||

IN_PROG is a bit unfortunate here as it mixes with 'prog' :P

> +	    !!vport->xdp_prog == !!prog) {
> +		if (np->state == __IDPF_VPORT_UP)
> +			idpf_copy_xdp_prog_to_qs(vport, prog);
> +
> +		old = xchg(&vport->xdp_prog, prog);
> +		if (old)
> +			bpf_prog_put(old);
> +
> +		cfg->user_config.xdp_prog = prog;
> +
> +		return 0;
> +	}
> +
> +	old = cfg->user_config.xdp_prog;
> +	cfg->user_config.xdp_prog = prog;
> +
> +	ret = idpf_initiate_soft_reset(vport, IDPF_SR_Q_CHANGE);
> +	if (ret) {
> +		NL_SET_ERR_MSG_MOD(xdp->extack,
> +				   "Could not reopen the vport after XDP setup");
> +
> +		if (prog)
> +			bpf_prog_put(prog);

aren't you missing this for prog->NULL conversion? you have this for
hot-swap case (prog->prog).

> +
> +		cfg->user_config.xdp_prog = old;
> +	}
> +
> +	return ret;
> +}
> +
> +/**
> + * idpf_xdp - handle XDP-related requests
> + * @dev: network device to configure
> + * @xdp: request data (program, extack)
> + *
> + * Return: 0 on success, -errno on failure.
> + */
> +int idpf_xdp(struct net_device *dev, struct netdev_bpf *xdp)
> +{
> +	struct idpf_vport *vport;
> +	int ret;
> +
> +	idpf_vport_ctrl_lock(dev);
> +	vport = idpf_netdev_to_vport(dev);
> +
> +	if (!idpf_is_queue_model_split(vport->txq_model))
> +		goto notsupp;
> +
> +	switch (xdp->command) {
> +	case XDP_SETUP_PROG:
> +		ret = idpf_xdp_setup_prog(vport, xdp);
> +		break;
> +	default:
> +notsupp:
> +		ret = -EOPNOTSUPP;
> +		break;
> +	}
> +
> +	idpf_vport_ctrl_unlock(dev);
> +
> +	return ret;
> +}
> -- 
> 2.48.1
>