Re: [PATCH] net: ethernet: ti: am65-cpsw: Add minimal XDP support

[Julien Panis <jpanis@baylibre.com>]

Hello Simon,

Thank you for the review.

On 2/26/24 18:25, Simon Horman wrote:
> On Fri, Feb 23, 2024 at 12:01:37PM +0100, Julien Panis wrote:
>> This patch adds XDP (eXpress Data Path) support to TI AM65 CPSW
>> Ethernet driver. The following features are implemented:
>> - NETDEV_XDP_ACT_BASIC (XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED)
>> - NETDEV_XDP_ACT_REDIRECT (XDP_REDIRECT)
>> - NETDEV_XDP_ACT_NDO_XMIT (ndo_xdp_xmit callback)
>>
>> Signed-off-by: Julien Panis <jpanis@baylibre.com>
> ...
>
>> @@ -440,6 +476,27 @@ static void am65_cpsw_nuss_tx_cleanup(void *data, dma_addr_t desc_dma)
>>   	dev_kfree_skb_any(skb);
>>   }
>>   
>> +static struct sk_buff *am65_cpsw_alloc_skb(struct net_device *ndev, unsigned int len)
>> +{
>> +	struct page *page;
>> +	struct sk_buff *skb;
> nit: please arrange local variables in reverse xmas tree order,
>       from longest line to shortest in new code.
>
>       This tool can be useful: https://github.com/ecree-solarflare/xmastree

You mean, for the new functions introduced in this patch only ?

>
>> +
>> +	page = dev_alloc_pages(0);
> nit: Maybe dev_alloc_page() is appropriate here?

Absolutely.

>
>> +	if (unlikely(!page))
>> +		return NULL;
>> +
>> +	len += AM65_CPSW_HEADROOM;
>> +
>> +	skb = build_skb(page_address(page), len);
>> +	if (unlikely(!skb))
> Does page need to be freed here?

Of course it does ! This will be fixed in the next version.

>
>> +		return NULL;
>> +
>> +	skb_reserve(skb, AM65_CPSW_HEADROOM + NET_IP_ALIGN);
>> +	skb->dev = ndev;
>> +
>> +	return skb;
>> +}
> ...