Re: [PATCH net] net: dsa: mt7530: don't change PVC_EG_TAG when CPU port becomes VLAN-aware

[Frank Wunderlich]

Am 6. Februar 2023 00:50:53 MEZ schrieb Vladimir Oltean <vladimir.oltean@xxxxxxx>:
>On Mon, Feb 06, 2023 at 02:02:48AM +0300, Arınç ÜNAL wrote:
>> # ethtool -S eth1 | grep -v ': 0'
>> NIC statistics:
>>      tx_bytes: 6272
>>      tx_packets: 81
>>      rx_bytes: 9089
>>      rx_packets: 136
>>      p05_TxUnicast: 52
>>      p05_TxMulticast: 3
>>      p05_TxBroadcast: 81
>>      p05_TxPktSz65To127: 136
>>      p05_TxBytes: 9633
>>      p05_RxFiltering: 11
>>      p05_RxUnicast: 11
>>      p05_RxMulticast: 26
>>      p05_RxBroadcast: 44
>>      p05_RxPktSz64: 47
>>      p05_RxPktSz65To127: 34
>>      p05_RxBytes: 6272
>> # ethtool -S eth1 | grep -v ': 0'
>> NIC statistics:
>>      tx_bytes: 6784
>>      tx_packets: 89
>>      rx_bytes: 9601
>>      rx_packets: 144
>>      p05_TxUnicast: 60
>>      p05_TxMulticast: 3
>>      p05_TxBroadcast: 81
>>      p05_TxPktSz65To127: 144
>>      p05_TxBytes: 10177
>>      p05_RxFiltering: 11
>>      p05_RxUnicast: 11
>>      p05_RxMulticast: 26
>>      p05_RxBroadcast: 52
>>      p05_RxPktSz64: 55
>>      p05_RxPktSz65To127: 34
>>      p05_RxBytes: 6784
>> # ethtool -S eth1 | grep -v ': 0'
>> NIC statistics:
>>      tx_bytes: 7424
>>      tx_packets: 99
>>      rx_bytes: 10241
>>      rx_packets: 154
>>      p05_TxUnicast: 70
>>      p05_TxMulticast: 3
>>      p05_TxBroadcast: 81
>>      p05_TxPktSz65To127: 154
>>      p05_TxBytes: 10857
>>      p05_RxFiltering: 11
>>      p05_RxUnicast: 11
>>      p05_RxMulticast: 26
>>      p05_RxBroadcast: 62
>>      p05_RxPktSz64: 65
>>      p05_RxPktSz65To127: 34
>>      p05_RxBytes: 7424
>
>I see no signs of packet loss on the DSA master or the CPU port.
>However my analysis of the packets shows:
>
>> # tcpdump -i eth1 -e -n -Q in -XX
>> tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
>> listening on eth1, link-type NULL (BSD loopback), snapshot length 262144 bytes
>> 03:50:38.645568 AF Unknown (2459068999), length 60: 
>> 	0x0000:  9292 6a47 1ac0 e0d5 5ea4 edcc 0806 0001  ..jG....^.......
>                 ^              ^              ^
>                 |              |              |
>                 |              |              ETH_P_ARP
>                 |              MAC SA:
>                 |              e0:d5:5e:a4:ed:cc
>                 MAC DA:
>                 92:92:6a:47:1a:c0
>
>> 	0x0010:  0800 0604 0002 e0d5 5ea4 edcc c0a8 0202  ........^.......
>> 	0x0020:  9292 6a47 1ac0 c0a8 0201 0000 0000 0000  ..jG............
>> 	0x0030:  0000 0000 0000 0000 0000 0000            ............
>
>So you have no tag_mtk header in the EtherType position where it's
>supposed to be. This means you must be making use of the hardware DSA
>untagging feature that Felix Fietkau added.
>
>Let's do some debugging. I'd like to know 2 things, in this order.
>First, whether DSA sees the accelerated header (stripped by hardware, as
>opposed to being present in the packet):
>
>diff --git a/net/dsa/tag.c b/net/dsa/tag.c
>index b2fba1a003ce..e64628cf7fc1 100644
>--- a/net/dsa/tag.c
>+++ b/net/dsa/tag.c
>@@ -75,12 +75,17 @@ static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
> 		if (!skb_has_extensions(skb))
> 			skb->slow_gro = 0;
> 
>+		netdev_err(dev, "%s: skb %px metadata dst contains port id %d attached\n",
>+			   __func__, skb, port);
>+
> 		skb->dev = dsa_master_find_slave(dev, 0, port);
> 		if (likely(skb->dev)) {
> 			dsa_default_offload_fwd_mark(skb);
> 			nskb = skb;
> 		}
> 	} else {
>+		netdev_err(dev, "%s: there is no metadata dst attached to skb 0x%px\n",
>+			   __func__, skb);
> 		nskb = cpu_dp->rcv(skb, dev);
> 	}
> 
>
>And second, which is what does the DSA master actually see, and put in
>the skb metadata dst field:
>
>diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>index f1cb1efc94cf..e7ff569959b4 100644
>--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>@@ -2077,11 +2077,23 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
> 		if (skb_vlan_tag_present(skb) && netdev_uses_dsa(netdev)) {
> 			unsigned int port = ntohs(skb->vlan_proto) & GENMASK(2, 0);
> 
>+			netdev_err(netdev, "%s: skb->vlan_proto 0x%x port %d\n", __func__,
>+				   ntohs(skb->vlan_proto), port);
>+
> 			if (port < ARRAY_SIZE(eth->dsa_meta) &&
>-			    eth->dsa_meta[port])
>+			    eth->dsa_meta[port]) {
>+				netdev_err(netdev, "%s: attaching metadata dst with port %d to skb 0x%px\n",
>+					   __func__, port, skb);
> 				skb_dst_set_noref(skb, &eth->dsa_meta[port]->dst);
>+			} else {
>+				netdev_err(netdev, "%s: not attaching any metadata dst to skb 0x%px\n",
>+					   __func__, skb);
>+			}
> 
> 			__vlan_hwaccel_clear_tag(skb);
>+		} else if (netdev_uses_dsa(netdev)) {
>+			netdev_err(netdev, "%s: received skb 0x%px without VLAN/DSA tag present\n",
>+				   __func__, skb);
> 		}
> 
> 		skb_record_rx_queue(skb, 0);
>
>Be warned that there may be a considerable amount of output to the console,
>so it would be best if you used a single switch port with small amounts
>of traffic.

Arınç have you tested with or without this series?

https://patchwork.kernel.org/project/linux-mediatek/list/?series=707666

Maybe try the opposite.

Have not see it in net-next yet.
regards Frank