On Thu, Aug 27, 2020 at 4:31 AM Miaohe Lin <linmia...@huawei.com> wrote: > > Set trailer iff skb1 is the skbuff where the tailbits space begins. > > Signed-off-by: Miaohe Lin <linmia...@huawei.com> > --- > net/core/skbuff.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 0b24aed04060..18ed56316e56 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -4488,8 +4488,9 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, > struct sk_buff **trailer) > skb1 = skb2; > } > elt++; > - *trailer = skb1; > skb_p = &skb1->next; > + if (!*skb_p) > + *trailer = skb1; >
Why is adding a conditional test going to help ? cpu will have hard time predicting this one, I doubt this kind of change is a win.