On Thu, 2020-12-10 at 18:59 +0100, Lorenzo Bianconi wrote:
> On Dec 10, Maciej Fijalkowski wrote:
> > On Thu, Dec 10, 2020 at 05:32:41PM +0100, Lorenzo Bianconi wrote:
> > > > On Thu, Dec 10, 2020 at 04:50:42PM +0100, Lorenzo Bianconi
> > > > wrote:
> > > > > Introduce xdp_init_buff utility routine to initialize
> > > > > xdp_buff data
> > > > > structure. Rely on xdp_init_buff in all XDP capable drivers.
> > > >
> > > > Hm, Jesper was suggesting two helpers, one that you implemented
> > > > for things
> > > > that are set once per NAPI and the other that is set per each
> > > > buffer.
> > > >
> > > > Not sure about the naming for a second one - xdp_prepare_buff ?
> > > > xdp_init_buff that you have feels ok.
> > >
> > > ack, so we can have xdp_init_buff() for initialization done once
> > > per NAPI run and
> > > xdp_prepare_buff() for per-NAPI iteration initialization, e.g.
> > >
> > > static inline void
> > > xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start,
> > > int headroom, int data_len)
> > > {
> > > xdp->data_hard_start = hard_start;
> > > xdp->data = hard_start + headroom;
> > > xdp->data_end = xdp->data + data_len;
> > > xdp_set_data_meta_invalid(xdp);
> > > }
> >
> > I think we should allow for setting the data_meta as well.
> > x64 calling convention states that first four args are placed onto
> > registers, so to keep it fast maybe have a third helper:
> >
> > static inline void
> > xdp_prepare_buff_meta(struct xdp_buff *xdp, unsigned char
> > *hard_start,
> > int headroom, int data_len)
> > {
> > xdp->data_hard_start = hard_start;
> > xdp->data = hard_start + headroom;
> > xdp->data_end = xdp->data + data_len;
> > xdp->data_meta = xdp->data;
> > }
> >
> > Thoughts?
>
> ack, I am fine with it. Let's wait for some feedback.
>
> Do you prefer to have xdp_prepare_buff/xdp_prepare_buff_meta in the
> same series
> of xdp_buff_init() or is it ok to address it in a separate patch?
>
you only need 2
why do you need xpd_prepare_buff_meta? that's exactly
what xdp_set_data_meta_invalid(xdp) is all about.
