On 18/08/02 (木) 22:53, Jesper Dangaard Brouer wrote:
On Thu, 2 Aug 2018 22:17:53 +0900
Toshiaki Makita <toshiaki.maki...@gmail.com> wrote:
On 18/08/02 (木) 20:45, Jesper Dangaard Brouer wrote:
On Thu, 2 Aug 2018 19:55:09 +0900
Toshiaki Makita <makita.toshi...@lab.ntt.co.jp> wrote:
+ headroom = frame->data - delta - (void *)frame;
Your calculation of headroom is still adding an assumption that
xdp_frame is located in the top of data area, that is unnecessary.
The headroom can be calculated as:
headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
Thanks. But I'm not sure I get what you are requesting.
I'm simply requesting you do not use the (void *)frame pointer address,
to calculate the headroom, as it can be calculated in another way.
I don't see difference, but ok I can change this calculation as you
prefer a different way.
Supposing xdp_frame is not located in the top of data area, what ensures
that additional sizeof(struct xdp_frame) can be used?
The calculation in convert_to_xdp_frame() assures this. If we later
add an xdp_frame that is not located in the top of data area, and want
to change the reserved headroom size, then we deal with it, and update
the code.
I just thought you are requesting the change so that we don't need to
change this code even when convert_to_xdp_frame() is changed. Now I see
my guess was wrong.
will send v8.
Thanks,
Toshiaki Makita
