Subject: Re: [PATCH net-next 0/3] VLANs, DSA switches and multiple bridges

From: Russell King - ARM Linux admin <[email-masked]>
Date: Thu, 20 Feb 2020 11:35:28 +0000

On Wed, Feb 19, 2020 at 01:07:07PM -0500, Vivien Didelot wrote:
> Hi Russell,
> 
> Some switches like the Marvell 88E6060 don't have a VTU, so programming the
> default PVID would return -EOPNOTSUPP.

The 88e6060 has its own driver separate from mv88e6xxx.

> Switches supporting only global VLAN
> filtering cannot have a VLAN filtering aware bridge as well as a non VLAN
> filtering aware bridge spanning their ports at the same time. But all this
> shouldn't be a problem because drivers inform the stack whether they support
> ds->vlan_filtering per-port, globally or not. We should simply reject the
> operation when vlan_filtering is being enabled on unsupported hardware.
> 
> Linux bridge is the reference for the implementation of an Ethernet bridge,
> if it programs VLAN entries, supported DSA hardware must do so. I'm not a
> fan of having our own bridge logic in DSA, so the limitation implemented by
> 2ea7a679ca2a ("net: dsa: Don't add vlans when vlan filtering is disabled")
> needs to go in my opinion.

... which is basically what patch 3 is doing, but in a per-driver
manner.

The checks introduced in 2ea7a679ca2a ("net: dsa: Don't add vlans when
vlan filtering is disabled") were raised up a level by c5335d737ff3
("net: dsa: check bridge VLAN in slave operations") to their present
positions, which are then touched by my patch 3 to make the checks
conditional.

-- 
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