Subject: Re: [net-next, PATCH 3/3, v2] net: netsec: add XDP support

From: Ivan Khoronzhuk <[email-masked]>
Date: Sun, 30 Jun 2019 19:25:53 +0300

On Sat, Jun 29, 2019 at 08:23:25AM +0300, Ilias Apalodimas wrote:
>The interface only supports 1 Tx queue so locking is introduced on
>the Tx queue if XDP is enabled to make sure .ndo_start_xmit and
>.ndo_xdp_xmit won't corrupt Tx ring
>
>- Performance (SMMU off)
>
>Benchmark   XDP_SKB     XDP_DRV
>xdp1        291kpps     344kpps
>rxdrop      282kpps     342kpps
>
>- Performance (SMMU on)
>Benchmark   XDP_SKB     XDP_DRV
>xdp1        167kpps     324kpps
>rxdrop      164kpps     323kpps
>
>Signed-off-by: Ilias Apalodimas <[email-masked]>
>---
> drivers/net/ethernet/socionext/netsec.c | 361 ++++++++++++++++++++++--
> 1 file changed, 334 insertions(+), 27 deletions(-)
>

[...]

>+
>+static int netsec_xdp_setup(struct netsec_priv *priv, struct bpf_prog *prog,
>+			    struct netlink_ext_ack *extack)
>+{
>+	struct net_device *dev = priv->ndev;
>+	struct bpf_prog *old_prog;
>+
>+	/* For now just support only the usual MTU sized frames */
>+	if (prog && dev->mtu > 1500) {
>+		NL_SET_ERR_MSG_MOD(extack, "Jumbo frames not supported on XDP");
>+		return -EOPNOTSUPP;
>+	}
>+
>+	if (netif_running(dev))
>+		netsec_netdev_stop(dev);
And why to stop the interface. XDP allows to update prog in runtime.

>+
>+	/* Detach old prog, if any */
>+	old_prog = xchg(&priv->xdp_prog, prog);
>+	if (old_prog)
>+		bpf_prog_put(old_prog);
>+
>+	if (netif_running(dev))
>+		netsec_netdev_open(dev);
>+
>+	return 0;
>+}
>+
>+static int netsec_xdp(struct net_device *ndev, struct netdev_bpf *xdp)
>+{
>+	struct netsec_priv *priv = netdev_priv(ndev);
>+
>+	switch (xdp->command) {
>+	case XDP_SETUP_PROG:
>+		return netsec_xdp_setup(priv, xdp->prog, xdp->extack);
>+	case XDP_QUERY_PROG:
>+		xdp->prog_id = priv->xdp_prog ? priv->xdp_prog->aux->id : 0;
>+		return 0;
>+	default:
>+		return -EINVAL;
>+	}
>+}
>+
> static const struct net_device_ops netsec_netdev_ops = {
> 	.ndo_init		= netsec_netdev_init,
> 	.ndo_uninit		= netsec_netdev_uninit,
>@@ -1537,6 +1842,8 @@ static const struct net_device_ops netsec_netdev_ops = {
> 	.ndo_set_mac_address    = eth_mac_addr,
> 	.ndo_validate_addr	= eth_validate_addr,
> 	.ndo_do_ioctl		= netsec_netdev_ioctl,
>+	.ndo_xdp_xmit		= netsec_xdp_xmit,
>+	.ndo_bpf		= netsec_xdp,
> };
>
> static int netsec_of_probe(struct platform_device *pdev,
>-- 
>2.20.1
>

-- 
Regards,
Ivan Khoronzhuk