Re: [PATCH net-next v1] net: stmmac: Enable TSO on VLANs

[Russell King (Oracle)]

On Thu, Jun 13, 2024 at 10:38:08AM +0800, Furong Xu wrote:
> @@ -4239,16 +4239,32 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
>  	struct stmmac_txq_stats *txq_stats;
>  	int tmp_pay_len = 0, first_tx;
>  	struct stmmac_tx_queue *tx_q;
> -	bool has_vlan, set_ic;
> +	bool set_ic;
>  	u8 proto_hdr_len, hdr;
>  	u32 pay_len, mss;
>  	dma_addr_t des;
>  	int i;
> +	struct vlan_ethhdr *veth;
>  
>  	tx_q = &priv->dma_conf.tx_queue[queue];
>  	txq_stats = &priv->xstats.txq_stats[queue];
>  	first_tx = tx_q->cur_tx;
>  
> +	if (skb_vlan_tag_present(skb)) {
> +		/* Always insert VLAN tag to SKB payload for TSO frames.
> +		 *
> +		 * Never insert VLAN tag by HW, since segments splited by
> +		 * TSO engine will be un-tagged by mistake.
> +		 */
> +		skb_push(skb, VLAN_HLEN);
> +		memmove(skb->data, skb->data + VLAN_HLEN, ETH_ALEN * 2);
> +
> +		veth = skb_vlan_eth_hdr(skb);
> +		veth->h_vlan_proto = skb->vlan_proto;
> +		veth->h_vlan_TCI = htons(skb_vlan_tag_get(skb));
> +		__vlan_hwaccel_clear_tag(skb);
> +	}

I think drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c::
otx2_sq_append_skb() does something similar, but uses a helper
instead:

        if (skb_shinfo(skb)->gso_size && !is_hw_tso_supported(pfvf, skb)) {
                /* Insert vlan tag before giving pkt to tso */
                if (skb_vlan_tag_present(skb))
                        skb = __vlan_hwaccel_push_inside(skb);
                otx2_sq_append_tso(pfvf, sq, skb, qidx);
                return true;
        }

Maybe __vlan_hwaccel_push_inside() should be used here?

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