linux-kernel - Re: [PATCH] net: dsa: mv88e6xxx: avoid error message on remove from VLAN 0

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Date:   Fri, 31 May 2019 09:44:04 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Vivien Didelot <vivien.didelot@...il.com>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        "David S. Miller" <davem@...emloft.net>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Marek Behún <marek.behun@....cz>,
        Russell King <rmk+kernel@...linux.org.uk>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Chris Healy <cphealy@...il.com>
Subject: Re: [PATCH] net: dsa: mv88e6xxx: avoid error message on remove from
 VLAN 0

On 5/31/19 7:31 AM, Vivien Didelot wrote:
> Hi Nikita,
> 
> On Fri, 31 May 2019 10:35:14 +0300, Nikita Yushchenko <nikita.yoush@...entembedded.com> wrote:
>> When non-bridged, non-vlan'ed mv88e6xxx port is moving down, error
>> message is logged:
>>
>> failed to kill vid 0081/0 for device eth_cu_1000_4
>>
>> This is caused by call from __vlan_vid_del() with vin set to zero, over
>> call chain this results into _mv88e6xxx_port_vlan_del() called with
>> vid=0, and mv88e6xxx_vtu_get() called from there returns -EINVAL.
>>
>> On symmetric path moving port up, call goes through
>> mv88e6xxx_port_vlan_prepare() that calls mv88e6xxx_port_check_hw_vlan()
>> that returns -EOPNOTSUPP for zero vid.
>>
>> This patch changes mv88e6xxx_vtu_get() to also return -EOPNOTSUPP for
>> zero vid, then this error code is explicitly cleared in
>> dsa_slave_vlan_rx_kill_vid() and error message is no longer logged.
>>
>> Signed-off-by: Nikita Yushchenko <nikita.yoush@...entembedded.com>
>> ---
>>  drivers/net/dsa/mv88e6xxx/chip.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
>> index 28414db979b0..6b77fde5f0e4 100644
>> --- a/drivers/net/dsa/mv88e6xxx/chip.c
>> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
>> @@ -1392,7 +1392,7 @@ static int mv88e6xxx_vtu_get(struct mv88e6xxx_chip *chip, u16 vid,
>>  	int err;
>>  
>>  	if (!vid)
>> -		return -EINVAL;
>> +		return -EOPNOTSUPP;
>>  
>>  	entry->vid = vid - 1;
>>  	entry->valid = false;
> 
> I'm not sure that I like the semantic of it, because the driver can actually
> support VID 0 per-se, only the kernel does not use VLAN 0. Thus I would avoid
> calling the port_vlan_del() ops for VID 0, directly into the upper DSA layer.
> 
> Florian, Andrew, wouldn't the following patch be more adequate?

See my comment about the usage of VLAN ID == 0 with non mv88e6xxx
switches this would break VLAN filtering/isolation for non bridged port.

> 
>     diff --git a/net/dsa/slave.c b/net/dsa/slave.c
>     index 1e2ae9d59b88..80f228258a92 100644
>     --- a/net/dsa/slave.c
>     +++ b/net/dsa/slave.c
>     @@ -1063,6 +1063,10 @@ static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
>             struct bridge_vlan_info info;
>             int ret;
>      
>     +       /* VID 0 has a special meaning and is never programmed in hardware */
>     +       if (!vid)
>     +               return 0;
>     +
>             /* Check for a possible bridge VLAN entry now since there is no
>              * need to emulate the switchdev prepare + commit phase.
>              */
> 
> 
> Thanks,
> Vivien
> 


-- 
Florian