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Date:   Thu, 2 Sep 2021 07:58:37 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     DENG Qingfang <dqfext@gmail.com>
Cc:     Sasha Levin <sashal@kernel.org>, stable@vger.kernel.org,
        Sean Wang <sean.wang@mediatek.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "open list:MEDIATEK SWITCH DRIVER" <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH 4.19.y] net: dsa: mt7530: disable learning on standalone
 ports
Message-ID: <YTBoDaYDJfBz3YzN@kroah.com>
References: <20210824055509.1316124-1-dqfext@gmail.com>
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On Thu, Sep 02, 2021 at 01:36:19PM +0800, DENG Qingfang wrote:
> On Fri, Aug 27, 2021 at 12:19:23PM +0200, Greg KH wrote:
> > On Tue, Aug 24, 2021 at 11:57:53PM +0800, DENG Qingfang wrote:
> > > Standalone ports should have address learning disabled, according to
> > > the documentation:
> > > https://www.kernel.org/doc/html/v5.14-rc7/networking/dsa/dsa.html#bridge-layer
> > > dsa_switch_ops on 5.10 or earlier does not have .port_bridge_flags
> > > function so it has to be done differently.
> > > 
> > > I've identified an issue related to this.
> > 
> > What issue is that?  Where was it reported?
> 
> See Florian's message here
> https://lore.kernel.org/stable/20210317003549.3964522-2-f.fainelli@gmail.com/

THat is just the patch changelog text, or is it unique to this
stable-only patch?  It is not obvious at all.

> > > > 2. A partial backport of this patch?
> > > 
> > > The other part does not actually fix anything.
> > 
> > Then why is it not ok to just take the whole thing?
> > 
> > When backporting not-identical-patches, something almost always goes
> > wrong, so we prefer to take the original commit when ever possible.
> 
> Okay. MDB and tag ops can be backported as is, and broadcast/multicast
> flooding can be implemented in .port_egress_floods. 

So what are we supposed to do here?

totally confused,

greg k-h