netdev - Re: [PATCH net-next v2 4/4] net: dsa: mt7530: always install FDB entries with IVL and FID 1

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Message-ID: <20210803182333.s2oc4yizwrzy746i@skbuf>
Date:   Tue, 3 Aug 2021 21:23:33 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     DENG Qingfang <dqfext@...il.com>
Cc:     Sean Wang <sean.wang@...iatek.com>,
        Landen Chao <Landen.Chao@...iatek.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        netdev@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Eric Woudstra <ericwouds@...il.com>,
        René van Dorst <opensource@...rst.com>,
        Frank Wunderlich <frank-w@...lic-files.de>,
        Ilya Lipnitskiy <ilya.lipnitskiy@...il.com>
Subject: Re: [PATCH net-next v2 4/4] net: dsa: mt7530: always install FDB
 entries with IVL and FID 1

On Wed, Aug 04, 2021 at 01:53:54AM +0800, DENG Qingfang wrote:
> On Tue, Aug 03, 2021 at 07:51:38PM +0300, Vladimir Oltean wrote:
> > 
> > The way FDB entries are installed now makes a lot more intuitive sense.
> 
> Did you forget to add the Reviewed-by tag?

Yeah, in fact I did. I was in a rush and by the time I figured that
I didn't do that, I had already left home.

Still, in fact the patch is obviously correct, which is nice. Standalone
ports never learn and the FDB lookup will always miss because it's in
FID 0 (a separate FID compared to the bridge ports) and there is no FDB
entry there. Packets will always be flooded to their only possible
destination, the CPU port. Ports under VLAN-unaware bridges always use
IVL and learn using the pvid, which is zero, and which happily coincides
with the VID which the bridge uses to install VLAN-unaware FDB entries.
Ports under VLAN-aware bridges again use IVL but the VID is taken from
the packet not just from the pvid, so the VID will be >= 1 there. Again
it coincides with the vid that the bridge uses to offload FDB entries.
Nice, I really like it, it is really simple.

Reviewed-by: Vladimir Oltean <olteanv@...il.com>