netdev - Re: [PATCH net-next 01/15] net: dsa: provide an option for drivers to always receive bridge VLANs

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Date:   Mon, 11 May 2020 14:59:12 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Russell King - ARM Linux admin <linux@...linux.org.uk>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vivien Didelot <vivien.didelot@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        netdev <netdev@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next 01/15] net: dsa: provide an option for drivers to
 always receive bridge VLANs

On Mon, 11 May 2020 at 14:54, Russell King - ARM Linux admin
<linux@...linux.org.uk> wrote:
>
> On Mon, May 11, 2020 at 02:40:29PM +0300, Vladimir Oltean wrote:
> > On Mon, 11 May 2020 at 14:38, Russell King - ARM Linux admin
> > <linux@...linux.org.uk> wrote:
> > >
> > > On Sun, May 10, 2020 at 07:42:41PM +0300, Vladimir Oltean wrote:
> > > > From: Russell King <rmk+kernel@...linux.org.uk>
> > > >
> > > > DSA assumes that a bridge which has vlan filtering disabled is not
> > > > vlan aware, and ignores all vlan configuration. However, the kernel
> > > > software bridge code allows configuration in this state.
> > > >
> > > > This causes the kernel's idea of the bridge vlan state and the
> > > > hardware state to disagree, so "bridge vlan show" indicates a correct
> > > > configuration but the hardware lacks all configuration. Even worse,
> > > > enabling vlan filtering on a DSA bridge immediately blocks all traffic
> > > > which, given the output of "bridge vlan show", is very confusing.
> > > >
> > > > Provide an option that drivers can set to indicate they want to receive
> > > > vlan configuration even when vlan filtering is disabled. At the very
> > > > least, this is safe for Marvell DSA bridges, which do not look up
> > > > ingress traffic in the VTU if the port is in 8021Q disabled state. It is
> > > > also safe for the Ocelot switch family. Whether this change is suitable
> > > > for all DSA bridges is not known.
> > > >
> > > > Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
> > > > Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
> > >
> > > This patch was NAK'd because of objections to the "vlan_bridge_vtu"
> > > name.  Unfortunately, this means that the bug for Marvell switches
> > > remains unfixed to this day.
> > >
> >
> > How about "accept_vlan_while_unaware"?
>
> It's up to DSA maintainers.
>
> However, I find that rather confusing. What's "unaware"? The point of
> this boolean is to program the vlan tables while vlan filtering is
> disabled. "accept_vlan_while_vlan_filtering_disabled" is way too long.
>

Considering the VLAN filtering modes as "disabled", "check",
"fallback" and "secure", I think a slight improvement over your
wording might be "install_vlans_while_disabled". I hope that is not
confusing and also not too long.

> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up