netdev - Re: [RFC V1 net-next 1/1] net: ena: implement XDP drop support

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Date:   Sun, 23 Jun 2019 16:09:24 +0200
From:   Jesper Dangaard Brouer <brouer@...hat.com>
To:     <sameehj@...zon.com>
Cc:     brouer@...hat.com, <davem@...emloft.net>, <netdev@...r.kernel.org>,
        <dwmw@...zon.com>, "Machulsky, Zorik" <zorik@...zon.com>,
        <matua@...zon.com>, <saeedb@...zon.com>, <msw@...zon.com>,
        <aliguori@...zon.com>, <nafea@...zon.com>, <gtzalik@...zon.com>,
        <netanel@...zon.com>, <alisaidi@...zon.com>, <benh@...zon.com>,
        <akiyano@...zon.com>, Daniel Borkmann <borkmann@...earbox.net>
Subject: Re: [RFC V1 net-next 1/1] net: ena: implement XDP drop support


I'm very happy to see progress with XDP for the ENA driver.

On Sun, 23 Jun 2019 10:06:49 +0300 <sameehj@...zon.com> wrote:

> @@ -888,6 +959,15 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
>  	va = page_address(rx_info->page) + rx_info->page_offset;
>  	prefetch(va + NET_IP_ALIGN);
>  
> +	if (ena_xdp_present_ring(rx_ring)) {
> +		rx_ring->xdp.data = va;
> +		rx_ring->xdp.data_meta = rx_ring->xdp.data;
> +		rx_ring->xdp.data_hard_start = rx_ring->xdp.data -
> +			rx_info->page_offset;
> +		rx_ring->xdp.data_end = rx_ring->xdp.data + len;
> +		if (ena_xdp_execute(rx_ring, &rx_ring->xdp) != XDP_PASS)
> +			return NULL;
> +	}

Looks like you forgot to init xdp.rxq pointer.

You can use the samples/bpf/xdp_rxq_info* to access this... and this
driver will likely crash if you use it...

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