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Date: Fri, 07 Jun 2024 15:31:57 +0200
From: Martin Schiller <ms@dev.tdt.de>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: martin.blumenstingl@googlemail.com, hauke@hauke-m.de, andrew@lunn.ch,
 f.fainelli@gmail.com, davem@davemloft.net, edumazet@google.com,
 kuba@kernel.org, pabeni@redhat.com, robh@kernel.org, krzk+dt@kernel.org,
 conor+dt@kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 09/13] net: dsa: lantiq_gswip: Forbid
 gswip_add_single_port_br on the CPU port
Organization: TDT AG
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References: <20240606085234.565551-1-ms@dev.tdt.de>
 <20240606085234.565551-10-ms@dev.tdt.de>
 <20240607112628.igcf6ytqe6wbmbq5@skbuf>
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On 2024-06-07 13:26, Vladimir Oltean wrote:
> On Thu, Jun 06, 2024 at 10:52:30AM +0200, Martin Schiller wrote:
>> From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
>> 
>> Calling gswip_add_single_port_br() with the CPU port would be a bug
>> because then only the CPU port could talk to itself. Add the CPU port 
>> to
>> the validation at the beginning of gswip_add_single_port_br().
>> 
>> Signed-off-by: Martin Blumenstingl 
>> <martin.blumenstingl@googlemail.com>
>> ---
>>  drivers/net/dsa/lantiq_gswip.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/net/dsa/lantiq_gswip.c 
>> b/drivers/net/dsa/lantiq_gswip.c
>> index ee8296d5b901..d2195271ffe9 100644
>> --- a/drivers/net/dsa/lantiq_gswip.c
>> +++ b/drivers/net/dsa/lantiq_gswip.c
>> @@ -657,7 +657,7 @@ static int gswip_add_single_port_br(struct 
>> gswip_priv *priv, int port, bool add)
>>  	unsigned int max_ports = priv->hw_info->max_ports;
>>  	int err;
>> 
>> -	if (port >= max_ports) {
>> +	if (port >= max_ports || dsa_is_cpu_port(priv->ds, port)) {
>>  		dev_err(priv->dev, "single port for %i supported\n", port);
>>  		return -EIO;
>>  	}
>> --
>> 2.39.2
>> 
> 
> Isn't the new check effectively dead code?

As long as the dsa_switch_ops .port_bridge_join and .port_bridge_leave 
are not
executed for the cpu port, I agree with you.