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

[Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxxxx>
> > Reviewed-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
>
>
> Acked-by: Jason Wang <jasowang@xxxxxxxxxx>

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))