Re: [PATCH net-next v5 05/15] net: airoha: Move DSA tag in DMA descriptor

Jakub Kicinski
2025-02-20T22:27:12Z

On Mon, 17 Feb 2025 14:01:09 +0100 Lorenzo Bianconi wrote:
> +static u32 airoha_get_dsa_tag(struct sk_buff *skb, struct net_device *dev)
> +{
> +#if IS_ENABLED(CONFIG_NET_DSA)
> + struct ethhdr *ehdr;
> + struct dsa_port *dp;
> + u8 xmit_tpid;
> + u16 tag;
> +
> + if (!netdev_uses_dsa(dev))
> + return 0;
> +
> + dp = dev->dsa_ptr;
> + if (IS_ERR(dp))
> + return 0;
> +
> + if (dp->tag_ops->proto != DSA_TAG_PROTO_MTK)
> + return 0;
> +
> + if (skb_ensure_writable(skb, ETH_HLEN))
> + return 0;

skb_cow_head() is a lot cheaper (for TCP)

> + ehdr = (struct ethhdr *)skb->data;
> + tag = be16_to_cpu(ehdr->h_proto);
> + xmit_tpid = tag >> 8;

> @@ -2390,8 +2498,10 @@ static int airoha_probe(struct platform_device *pdev)
> for (i = 0; i < ARRAY_SIZE(eth->ports); i++) {
> struct airoha_gdm_port *port = eth->ports[i];
>
> - if (port && port->dev->reg_state == NETREG_REGISTERED)
> + if (port && port->dev->reg_state == NETREG_REGISTERED) {
> + airoha_metadata_dst_free(port);
> unregister_netdev(port->dev);

Looks a tiny bit reversed, isn't it?
First unregister the netdev, then free its metadata.

> + }
> }
> free_netdev(eth->napi_dev);
> platform_set_drvdata(pdev, NULL);
> @@ -2416,6 +2526,7 @@ static void airoha_remove(struct platform_device *pdev)
> continue;
>
> airoha_dev_stop(port->dev);
> + airoha_metadata_dst_free(port);
> unregister_netdev(port->dev);

same here

> }
> free_netdev(eth->napi_dev);