Re: [PATCH net-next 2/2] netdevsim: collect statistics at RX side

[Joe Damato <joe@dama.to>]

On Wed, Jun 11, 2025 at 08:06:20AM -0700, Breno Leitao wrote:
> When the RX side of netdevsim was added, the RX statistics were missing,
> making the driver unusable for GenerateTraffic() test framework.
> 
> This patch adds proper statistics tracking on RX side, complementing the
> TX path.
> 
> Signed-off-by: Breno Leitao <Leitao@debian.org>
> ---
>  drivers/net/netdevsim/netdev.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
> index 67871d31252fe..590cb5bb0d20b 100644
> --- a/drivers/net/netdevsim/netdev.c
> +++ b/drivers/net/netdevsim/netdev.c
> @@ -39,12 +39,16 @@ MODULE_IMPORT_NS("NETDEV_INTERNAL");
>  
>  static int nsim_napi_rx(struct nsim_rq *rq, struct sk_buff *skb)
>  {
> +	struct net_device *dev = rq->napi.dev;
> +
>  	if (skb_queue_len(&rq->skb_queue) > NSIM_RING_SIZE) {
>  		dev_kfree_skb_any(skb);
> +		dev_dstats_rx_dropped(dev);
>  		return NET_RX_DROP;
>  	}
>  
>  	skb_queue_tail(&rq->skb_queue, skb);
> +	dev_dstats_rx_add(dev, skb->len);
>  	return NET_RX_SUCCESS;
>  }

Hm, I was wondering: is it maybe better to add the stats code to nsim_poll or
nsim_rcv instead?

It "feels" like other drivers would be bumping RX stats in their NAPI poll
function (which is nsim_poll, the naming of the functions is a bit confusing
here), so it seems like netdevsim maybe should too?