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Date:   Thu, 13 Oct 2022 14:15:59 -0400
From:   Sasha Levin <sashal@kernel.org>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>, andrew@lunn.ch,
        vivien.didelot@gmail.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 6.0 11/77] net: dsa: all DSA masters must be down
 when changing the tagging protocol
Message-ID: <Y0hV36EMAvOOm79K@sashalap>
References: <20221009220754.1214186-1-sashal@kernel.org>
 <20221009220754.1214186-11-sashal@kernel.org>
 <20221010115430.kloc3urkycsbyele@skbuf>
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On Mon, Oct 10, 2022 at 02:54:30PM +0300, Vladimir Oltean wrote:
>On Sun, Oct 09, 2022 at 06:06:48PM -0400, Sasha Levin wrote:
>> From: Vladimir Oltean <vladimir.oltean@nxp.com>
>>
>> [ Upstream commit f41ec1fd1c20e2a4e60a4ab8490b3e63423c0a8a ]
>>
>> The fact that the tagging protocol is set and queried from the
>> /sys/class/net/<dsa-master>/dsa/tagging file is a bit of a quirk from
>> the single CPU port days which isn't aging very well now that DSA can
>> have more than a single CPU port. This is because the tagging protocol
>> is a switch property, yet in the presence of multiple CPU ports it can
>> be queried and set from multiple sysfs files, all of which are handled
>> by the same implementation.
>>
>> The current logic ensures that the net device whose sysfs file we're
>> changing the tagging protocol through must be down. That net device is
>> the DSA master, and this is fine for single DSA master / CPU port setups.
>>
>> But exactly because the tagging protocol is per switch [ tree, in fact ]
>> and not per DSA master, this isn't fine any longer with multiple CPU
>> ports, and we must iterate through the tree and find all DSA masters,
>> and make sure that all of them are down.
>>
>> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
>> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
>> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>
>Not needed for stable kernels, please drop, thanks.

Ack, I'll drop this and the rest of the patches you've pointed out,
thanks!

-- 
Thanks,
Sasha