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

[Linus Walleij]

On Mon, Oct 14, 2024 at 5:30 PM Vladimir Oltean <vladimir.oltean@xxxxxxx> wrote:

> 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>

Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij