On Tue, 15 May 2018 21:06:15 +0200 Björn Töpel <bjorn.to...@gmail.com> wrote:
> From: Magnus Karlsson <magnus.karls...@intel.com>
>
> Here, the zero-copy ndo is implemented. As a shortcut, the existing
> XDP Tx rings are used for zero-copy. This means that and XDP program
> cannot redirect to an AF_XDP enabled XDP Tx ring.
This "shortcut" is not acceptable, and completely broken. The
XDP_REDIRECT queue_index is based on smp_processor_id(), and can easily
clash with the configured XSK queue_index. Provided a bit more code
context below...
On Tue, 15 May 2018 21:06:15 +0200
Björn Töpel <bjorn.to...@gmail.com> wrote:
int i40e_xdp_xmit(struct net_device *dev, struct xdp_frame *xdpf)
{
struct i40e_netdev_priv *np = netdev_priv(dev);
unsigned int queue_index = smp_processor_id();
struct i40e_vsi *vsi = np->vsi;
int err;
if (test_bit(__I40E_VSI_DOWN, vsi->state))
return -ENETDOWN;
> @@ -4025,6 +4158,9 @@ int i40e_xdp_xmit(struct net_device *dev, struct
> xdp_frame *xdpf)
> if (!i40e_enabled_xdp_vsi(vsi) || queue_index >= vsi->num_queue_pairs)
> return -ENXIO;
>
> + if (vsi->xdp_rings[queue_index]->xsk_umem)
> + return -ENXIO;
> +
Using the sane errno makes this impossible to debug (via the tracepoints).
> err = i40e_xmit_xdp_ring(xdpf, vsi->xdp_rings[queue_index]);
> if (err != I40E_XDP_TX)
> return -ENOSPC;
> @@ -4048,5 +4184,34 @@ void i40e_xdp_flush(struct net_device *dev)
> if (!i40e_enabled_xdp_vsi(vsi) || queue_index >= vsi->num_queue_pairs)
> return;
>
> + if (vsi->xdp_rings[queue_index]->xsk_umem)
> + return;
> +
> i40e_xdp_ring_update_tail(vsi->xdp_rings[queue_index]);
> }
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
