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

[Heng Qi <hengqi@linux.alibaba.com>]

在 2022/12/27 下午3:55, Jason Wang 写道:
>
> 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 for your energy.

>
> 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))