[PATCH v2 net] net: dsa: vsc73xx: fix reception from VLAN-unaware bridges

From: Vladimir Oltean
Date: Mon Oct 14 2024 - 11:34:01 EST


Similar to the situation described for sja1105 in commit 1f9fc48fd302
("net: dsa: sja1105: fix reception from VLAN-unaware bridges"), the
vsc73xx driver uses tag_8021q and doesn't need the ds->untag_bridge_pvid
request. In fact, this option breaks packet reception.

The ds->untag_bridge_pvid option strips VLANs from packets received on
VLAN-unaware bridge ports. But those VLANs should already be stripped
by tag_vsc73xx_8021q.c as part of vsc73xx_rcv() - they are not VLANs in
VLAN-unaware mode, but DSA tags. Thus, dsa_software_vlan_untag() tries
to untag a VLAN that doesn't exist, corrupting the packet.

Fixes: 93e4649efa96 ("net: dsa: provide a software untagging function on RX for VLAN-aware bridges")
Tested-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
v1->v2:
- retarget to 'net'
- rewrite commit message

Link to v1:
https://lore.kernel.org/netdev/20241008104657.3549151-1-vladimir.oltean@xxxxxxx/

drivers/net/dsa/vitesse-vsc73xx-core.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
index e4b98fd51643..f18aa321053d 100644
--- a/drivers/net/dsa/vitesse-vsc73xx-core.c
+++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
@@ -851,7 +851,6 @@ static int vsc73xx_setup(struct dsa_switch *ds)

dev_info(vsc->dev, "set up the switch\n");

- ds->untag_bridge_pvid = true;
ds->max_num_bridges = DSA_TAG_8021Q_MAX_NUM_BRIDGES;
ds->fdb_isolation = true;

--
2.43.0