netdev - Re: Cannot set ageing to zero

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Message-ID: <20160126174830.GE2195@nanopsycho.orion>
Date:	Tue, 26 Jan 2016 18:48:30 +0100
From:	Jiri Pirko <jiri@...nulli.us>
To:	Flavio Leitner <fbl@...close.org>
Cc:	netdev <netdev@...r.kernel.org>, Scott Feldman <sfeldma@...il.com>
Subject: Re: Cannot set ageing to zero

Tue, Jan 26, 2016 at 06:44:24PM CET, fbl@...close.org wrote:
>On Tue, 26 Jan 2016 18:30:41 +0100
>Jiri Pirko <jiri@...nulli.us> wrote:
>
>> Tue, Jan 26, 2016 at 06:26:30PM CET, fbl@...close.org wrote:
>> >
>> >Hi,
>> >
>> >After the commit[1] below, we can't set ageing on a Linux bridge
>> >device to zero.  It seems rocker needs the minimum value, but we
>> >can't break an old and valid Linux bridge behavior.   
>> 
>> The commit below adds check if the value being set is within
>> BR_MIN_AGEING_TIME and BR_MAX_AGEING_TIME. I believe that the check is
>> correct as it implements the standard.
>>
>> Why do you set ageing_time to 0? Why don't just just disable learning?
>
>It's a documented behavior:
>http://www.linuxcertif.com/man/5/ifcfg-bridge/
>http://www.linuxfoundation.org/collaborate/workgroups/networking/bridge
>http://comments.gmane.org/gmane.linux.network.bridge/2060

0 makes entries permanent. Fair enough. Feel free to send patch moving
the check inside switchdev_port_attr_set or into drivers. I can put it
in my todo list if you want.

Thanks!


>
>fbl
>
>> 
>> 
>> >
>> >[1] commit c62987bbd8a1a1664f99e89e3959339350a6131e
>> >Author: Scott Feldman <sfeldma@...il.com>
>> >Date:   Thu Oct 8 19:23:19 2015 -0700
>> >
>> >    bridge: push bridge setting ageing_time down to switchdev
>> >    
>> >    Use SWITCHDEV_F_SKIP_EOPNOTSUPP to skip over ports in bridge that
>> >    don't support setting ageing_time (or setting bridge attrs in
>> >    general). 
>> >    If push fails, don't update ageing_time in bridge and return err
>> > to user. 
>> >    If push succeeds, update ageing_time in bridge and run gc_timer
>> > now to recalabrate when to run gc_timer next, based on new
>> > ageing_time. 
>> >    Signed-off-by: Scott Feldman <sfeldma@...il.com>
>> >    Signed-off-by: Jiri Pirko <jiri@...nulli.us>
>> >    Acked-by: Jiri Pirko <jiri@...lanox.com>
>> >    Signed-off-by: David S. Miller <davem@...emloft.net>
>> >
>> >
>> >-- 
>> >fbl
>> >  
>
>
>
>-- 
>fbl
>