Re: [PATCH] bonding: move IPv6 support into a separate kernel module

[Brian Haley <brian.haley@hp.com>]

David Miller wrote:
> From: Brian Haley <brian.haley@hp.com>
> Date: Fri, 20 Feb 2009 19:31:29 -0500
> 
>> [Possible fix for bonding IPv6 regression reported by Andrey Borzenkov,
>> tried to keep all Cc's]
>>
>> This patch moves the IPv6 bonding code into a separate kernel module
>> called bonding_ipv6 if either bonding or IPv6 are built as modules.
>> If both are built into the kernel then this is as well.  Bonding_ipv6.ko
>> registers an "send_unsol_na" function pointer for the unsolicited
>> advertisement function to be called on a failover - the default action
>> is to do nothing.  The notifier callbacks are now registered in this
>> module and not in the base bonding module.
>>
>> Signed-off-by: Brian Haley <brian.haley@hp.com>
> 
> Thanks for taking the time to work on this Brian.
> 
> I wonder if we aren't just trading one evil for another.
> 
> Right now just configuring bonding will get the bonding
> module loaded and the ipv6 facilities will be visible.
> 
> Now with your change, the user has to explicitly load
> the module.  That's extremely user-unfriendly.

I agree, part of me just wanted to make sure it could be done, and figured it 
was just a matter of time before my hand was forced, or the original commit was 
reverted.

One idea is that the IPv6 notifier, addrconf_notify(), could try and load the 
bonding_ipv6 module if a device with IFF_MASTER registered.  I haven't 
prototyped it to see if it would actually work, seemed like a hack.

-Brian