Subject: Re: [patch net-next 16/26] bonding: implement lower state change propagation

From: Nikolay Aleksandrov <[email-masked]>
Date: Wed, 2 Dec 2015 12:47:16 +0100

On 12/02/2015 12:40 PM, Nikolay Aleksandrov wrote:
> On 12/01/2015 02:48 PM, Jiri Pirko wrote:
>> From: Jiri Pirko <[email-masked]>
>>
>> Let netdev notifier listeners know about link and slave state change.
>>
>> Signed-off-by: Jiri Pirko <[email-masked]>
>> ---
>>  drivers/net/bonding/bond_main.c | 10 ++++++++++
>>  include/net/bonding.h           |  7 +++++++
>>  2 files changed, 17 insertions(+)
>>
>> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>> index c9943fc..e153a87 100644
>> --- a/drivers/net/bonding/bond_main.c
>> +++ b/drivers/net/bonding/bond_main.c
>> @@ -1315,6 +1315,16 @@ void bond_queue_slave_event(struct slave *slave)
>>  	queue_delayed_work(slave->bond->wq, &nnw->work, 0);
>>  }
>>  
>> +void bond_lower_state_changed(struct slave *slave)
>> +{
>> +	struct netdev_lag_lower_state_info info;
>> +
>> +	info.link_up = slave->link == BOND_LINK_UP ||
>> +		       slave->link == BOND_LINK_FAIL;
>> +	info.tx_enabled = bond_is_active_slave(slave);
>> +	netdev_lower_state_changed(slave->dev, &info);
>> +}
>> +
> 
> Hmm, but does this tell the listeners what changed ? I think it just
> sends the current slave state and the listener has to decide what has
> changed.
> For example, right now it's possible for multiple identical events to
> be sent (e.g. set_inactive_flags called two times on release, once because
> of curr_active_slave change and second because of your set), the listeners
> should be able to cope with that. For this same example I see that the mlxsw
> will call mlxsw_sp_port_lag_changed() two times with the same values in that
> case. I'm not saying this is necessarily bad, just noting it. :-)
> 
> 
Oh well, I see there's a check in bond_set_slave_state() that will prevent the
second notification if the state is the same, so okay. This case in 
particular is averted.