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Message-ID: <1c2fe59a-daf6-4486-84ca-5880222d24bd@baylibre.com>
Date: Mon, 26 Feb 2024 18:48:25 +0100
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Subject: Re: [PATCH] net: ethernet: ti: am65-cpsw: Add minimal XDP support
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To: Simon Horman <horms@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
 Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>,
 Paolo Abeni <pabeni@redhat.com>, Russell King <linux@armlinux.org.uk>,
 Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>,
 Jesper Dangaard Brouer <hawk@kernel.org>,
 John Fastabend <john.fastabend@gmail.com>,
 Sumit Semwal <sumit.semwal@linaro.org>,
 =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
 netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
 linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
 linaro-mm-sig@lists.linaro.org
References: <20240223-am65-cpsw-xdp-basic-v1-1-9f0b6cbda310@baylibre.com>
 <20240226172533.GG13129@kernel.org>
From: Julien Panis <jpanis@baylibre.com>
In-Reply-To: <20240226172533.GG13129@kernel.org>
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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;
>> +}
> ...