Den lör 28 juli 2018 kl 05:21 skrev Jakub Kicinski
<jakub.kicin...@netronome.com>:
>
> xdp_return_buff() is used when frame has been successfully
> handled (transmitted) or if an error occurred during delayed
> processing and there is no way to report it back to
> xdp_do_redirect().
>
> In case of __xsk_rcv_zc() error is propagated all the way
> back to the driver, so there is no need to call
> xdp_return_buff(). Driver will recycle the frame anyway
> after seeing that error happened.
>
> Fixes: 173d3adb6f43 ("xsk: add zero-copy support for Rx")
> Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
> ---
> Patch could as well be applied to bpf-next, since there are no drivers
> for AF_XDP in tree, yet. xdp_umem_get_dma() and xdp_umem_get_data() are
> not even exported. But one could reimplent those...
>
> As I mentioned I think this makes the entire MEM_TYPE_ZERO_COPY allocator
> handling dead code now :(
>
Nice Jakub!
Indeed, as you state, there's no ZC driver implementation yet. So,
either bpf or bpf-next.
Acked-by: Björn Töpel <bjorn.to...@intel.com>
> net/xdp/xsk.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index 72335c2e8108..4e937cd7c17d 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -84,10 +84,8 @@ static int __xsk_rcv_zc(struct xdp_sock *xs, struct
> xdp_buff *xdp, u32 len)
> {
> int err = xskq_produce_batch_desc(xs->rx, (u64)xdp->handle, len);
>
> - if (err) {
> - xdp_return_buff(xdp);
> + if (err)
> xs->rx_dropped++;
> - }
>
> return err;
> }
> --
> 2.17.1
>
