Re: [PATCH v2 8/9] virtio_net: remove xdp related info from page_to_skb()

[Jason Wang <jasowang@redhat.com>]

在 2022/12/20 22:14, Heng Qi 写道:
> For the clear construction of xdp_buff, we remove the xdp processing
> interleaved with page_to_skb(). Now, the logic of xdp and building
> skb from xdp are separate and independent.
>
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
> Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>


Acked-by: Jason Wang <jasowang@redhat.com>

Thanks


> ---
>   drivers/net/virtio_net.c | 41 +++++++++-------------------------------
>   1 file changed, 9 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 4e12196fcfd4..398ffe2a5084 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -439,9 +439,7 @@ static unsigned int mergeable_ctx_to_truesize(void *mrg_ctx)
>   static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>   				   struct receive_queue *rq,
>   				   struct page *page, unsigned int offset,
> -				   unsigned int len, unsigned int truesize,
> -				   bool hdr_valid, unsigned int metasize,
> -				   unsigned int headroom)
> +				   unsigned int len, unsigned int truesize)
>   {
>   	struct sk_buff *skb;
>   	struct virtio_net_hdr_mrg_rxbuf *hdr;
> @@ -459,21 +457,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>   	else
>   		hdr_padded_len = sizeof(struct padded_vnet_hdr);
>   
> -	/* If headroom is not 0, there is an offset between the beginning of the
> -	 * data and the allocated space, otherwise the data and the allocated
> -	 * space are aligned.
> -	 *
> -	 * Buffers with headroom use PAGE_SIZE as alloc size, see
> -	 * add_recvbuf_mergeable() + get_mergeable_buf_len()
> -	 */
> -	truesize = headroom ? PAGE_SIZE : truesize;
> -	tailroom = truesize - headroom;
> -	buf = p - headroom;
> -
> +	buf = p;
>   	len -= hdr_len;
>   	offset += hdr_padded_len;
>   	p += hdr_padded_len;
> -	tailroom -= hdr_padded_len + len;
> +	tailroom = truesize - hdr_padded_len - len;
>   
>   	shinfo_size = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
>   
> @@ -503,7 +491,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>   	if (len <= skb_tailroom(skb))
>   		copy = len;
>   	else
> -		copy = ETH_HLEN + metasize;
> +		copy = ETH_HLEN;
>   	skb_put_data(skb, p, copy);
>   
>   	len -= copy;
> @@ -542,19 +530,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>   		give_pages(rq, page);
>   
>   ok:
> -	/* hdr_valid means no XDP, so we can copy the vnet header */
> -	if (hdr_valid) {
> -		hdr = skb_vnet_hdr(skb);
> -		memcpy(hdr, hdr_p, hdr_len);
> -	}
> +	hdr = skb_vnet_hdr(skb);
> +	memcpy(hdr, hdr_p, hdr_len);
>   	if (page_to_free)
>   		put_page(page_to_free);
>   
> -	if (metasize) {
> -		__skb_pull(skb, metasize);
> -		skb_metadata_set(skb, metasize);
> -	}
> -
>   	return skb;
>   }
>   
> @@ -934,7 +914,7 @@ static struct sk_buff *receive_big(struct net_device *dev,
>   {
>   	struct page *page = buf;
>   	struct sk_buff *skb =
> -		page_to_skb(vi, rq, page, 0, len, PAGE_SIZE, true, 0, 0);
> +		page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
>   
>   	stats->bytes += len - vi->hdr_len;
>   	if (unlikely(!skb))
> @@ -1222,9 +1202,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>   				rcu_read_unlock();
>   				put_page(page);
>   				head_skb = page_to_skb(vi, rq, xdp_page, offset,
> -						       len, PAGE_SIZE, false,
> -						       metasize,
> -						       headroom);
> +						       len, PAGE_SIZE);
>   				return head_skb;
>   			}
>   			break;
> @@ -1289,8 +1267,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>   	rcu_read_unlock();
>   
>   skip_xdp:
> -	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,
> -			       metasize, headroom);
> +	head_skb = page_to_skb(vi, rq, page, offset, len, truesize);
>   	curr_skb = head_skb;
>   
>   	if (unlikely(!curr_skb))