Re: [PATCH net-next 1/2] net: introduce skb_coalesce_rx_frag()

[Jason Wang <jasowang@redhat.com>]

On 10/31/2013 07:05 PM, Kmindg G wrote:
> On Thu, Oct 31, 2013 at 6:28 PM, Jason Wang <jasowang@redhat.com> wrote:
>> > Sometimes we need to coalesce the rx frags to avoid frag list. One example is
>> > virtio-net driver which tries to use small frags for both MTU sized packet and
>> > GSO packet. So this patch introduce skb_coalesce_rx_frag() to do this.
>> >
>> > Cc: Rusty Russell <rusty@rustcorp.com.au>
>> > Cc: Michael S. Tsirkin <mst@redhat.com>
>> > Cc: Michael Dalton <mwdalton@google.com>
>> > Cc: Eric Dumazet <edumazet@google.com>
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
>> > ---
>> >  include/linux/skbuff.h |  3 +++
>> >  net/core/skbuff.c      | 13 +++++++++++++
>> >  2 files changed, 16 insertions(+)
>> >
>> > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
>> > index 2c15497..e34652b 100644
>> > --- a/include/linux/skbuff.h
>> > +++ b/include/linux/skbuff.h
>> > @@ -1372,6 +1372,9 @@ static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
>> >  void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
>> >                      int size, unsigned int truesize);
>> >
>> > +void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int off, int size,
>> > +                         unsigned int truesize);
>> > +
>> >  #define SKB_PAGE_ASSERT(skb)   BUG_ON(skb_shinfo(skb)->nr_frags)
>> >  #define SKB_FRAG_ASSERT(skb)   BUG_ON(skb_has_frag_list(skb))
>> >  #define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
>> > diff --git a/net/core/skbuff.c b/net/core/skbuff.c
>> > index 0ab32fa..fdef994 100644
>> > --- a/net/core/skbuff.c
>> > +++ b/net/core/skbuff.c
>> > @@ -476,6 +476,19 @@ void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
>> >  }
>> >  EXPORT_SYMBOL(skb_add_rx_frag);
>> >
>> > +void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int off, int size,
>> > +                         unsigned int truesize)
>> > +{
>> > +       skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
>> > +
>> > +       skb_frag_size_add(frag, size);
>> > +       skb->len += size;
>> > +       skb->data_len += size;
>> > +       skb->truesize += truesize;
>> > +       skb_frag_unref(skb, i);
>> > +}
> I didn't see  you use "off" in skb_coalesce_rx_frag.
>

Ture, it's useless. Will post V2.

Thanks