Subject: Re: [net-next 10/13] net/mlx5e: Add support for XDP_REDIRECT in device-out side

From: Jesper Dangaard Brouer <[email-masked]>
Date: Mon, 30 Jul 2018 14:10:21 +0200

On Thu, 26 Jul 2018 15:56:44 -0700 Saeed Mahameed <[email-masked]> wrote:

> +int mlx5e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
> +		   u32 flags)
> +{
> +	struct mlx5e_priv *priv = netdev_priv(dev);
> +	struct mlx5e_xdpsq *sq;
> +	int drops = 0;
> +	int sq_num;
> +	int i;
> +
> +	if (unlikely(!test_bit(MLX5E_STATE_OPENED, &priv->state)))
> +		return -ENETDOWN;
> +
> +	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
> +		return -EINVAL;
> +
> +	sq_num = smp_processor_id();
> +
> +	if (unlikely(sq_num >= priv->channels.num))
> +		return -ENXIO;
> +
> +	sq = &priv->channels.c[sq_num]->xdpsq;
> +
> +	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))
> +		return -ENETDOWN;
> +
> +	for (i = 0; i < n; i++) {
> +		struct xdp_frame *xdpf = frames[i];
> +		struct mlx5e_xdp_info xdpi;
> +
> +		xdpi.dma_addr = dma_map_single(sq->pdev, xdpf->data, xdpf->len,
> +					       DMA_TO_DEVICE);
> +		if (unlikely(dma_mapping_error(sq->pdev, xdpi.dma_addr))) {
> +			drops++;

I think you are missing a xdp_return_frame_rx_napi(xdpf) here.

> +			continue;
> +		}
> +
> +		xdpi.xdpf = xdpf;
> +
> +		if (unlikely(!mlx5e_xmit_xdp_frame(sq, &xdpi))) {
> +			xdp_return_frame_rx_napi(xdpf);
> +			drops++;
> +		}
> +	}
> +
> +	if (flags & XDP_XMIT_FLUSH)
> +		mlx5e_xmit_xdp_doorbell(sq);
> +
> +	return n - drops;
> +}

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer