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

[Arınç ÜNAL]

On 6.02.2023 10:35, Frank Wunderlich wrote:
> Am 6. Februar 2023 00:50:53 MEZ schrieb Vladimir Oltean <vladimir.oltean at nxp.com>:
>> 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

I'm trying this without it, this is the tree I'm testing.

https://github.com/arinc9/linux/commits/test-for-richard

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