Re: [PATCH v2 net-next 4/4] net: dsa: tag_dsa: Support reception of packets from LAG devices

[Vladimir Oltean <olteanv@gmail.com>]

On Mon, Nov 30, 2020 at 03:06:10PM +0100, Tobias Waldekranz wrote:
> Packets ingressing on a LAG that egress on the CPU port, which are not
> classified as management, will have a FORWARD tag that does not
> contain the normal source device/port tuple. Instead the trunk bit
> will be set, and the port field holds the LAG id.
> 
> Since the exact source port information is not available in the tag,
> frames are injected directly on the LAG interface and thus do never
> pass through any DSA port interface on ingress.
> 
> Management frames (TO_CPU) are not affected and will pass through the
> DSA port interface as usual.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
> ---
>  net/dsa/dsa.c     | 12 +++++++++++-
>  net/dsa/tag_dsa.c | 17 ++++++++++++++++-
>  2 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
> index a1b1dc8a4d87..7325bf4608e9 100644
> --- a/net/dsa/dsa.c
> +++ b/net/dsa/dsa.c
> @@ -219,11 +219,21 @@ static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
>  	}
>  
>  	skb = nskb;
> -	p = netdev_priv(skb->dev);
>  	skb_push(skb, ETH_HLEN);
>  	skb->pkt_type = PACKET_HOST;
>  	skb->protocol = eth_type_trans(skb, skb->dev);
>  
> +	if (unlikely(!dsa_slave_dev_check(skb->dev))) {
> +		/* Packet is to be injected directly on an upper
> +		 * device, e.g. a team/bond, so skip all DSA-port
> +		 * specific actions.
> +		 */
> +		netif_rx(skb);
> +		return 0;

netif_rx returns an int code, it seems odd to ignore it.

> +	}
> +
> +	p = netdev_priv(skb->dev);
> +
>  	if (unlikely(cpu_dp->ds->untag_bridge_pvid)) {
>  		nskb = dsa_untag_bridge_pvid(skb);
>  		if (!nskb) {