Re: [patch net-next 24/26] mlxsw: spectrum: Implement LAG port join/leave

[Jiri Pirko <jiri@resnulli.us>]

Wed, Dec 02, 2015 at 06:30:07PM CET, davem@davemloft.net wrote:
>From: Or Gerlitz <gerlitz.or@gmail.com>
>Date: Wed, 2 Dec 2015 07:47:51 +0200
>
>> On Tue, Dec 1, 2015 at 3:49 PM, Jiri Pirko <jiri@resnulli.us> wrote:
>>> Implement basic procedures for joining/leaving port to/from LAG. That
>>> includes HW setup of collector, core LAG mapping setup.
>>>
>>> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
>>> ---
>>>  drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 284 +++++++++++++++++++++++--
>>>  drivers/net/ethernet/mellanox/mlxsw/spectrum.h |  35 ++-
>>>  2 files changed, 302 insertions(+), 17 deletions(-)
>>>
>>> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
>>> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
>> 
>> [...]
>> 
>>> +static int mlxsw_sp_port_lag_leave(struct mlxsw_sp_port *mlxsw_sp_port,
>>> +                                  struct net_device *lag_dev)
>>> +{
>>> +       struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
>>> +       struct mlxsw_sp_upper *lag;
>>> +       u16 lag_id = mlxsw_sp_port->lag_id;
>>> +       int err;
>>> +
>>> +       if (!mlxsw_sp_port->lagged)
>>> +               return 0;
>>> +       lag = mlxsw_sp_lag_get(mlxsw_sp, lag_id);
>>> +       BUG_ON(lag->ref_count == 0);
>> 
>> is this a must to crash the system here? can't we do something less drastic?
>
>Indeed, please use WARN_ON() and return an error or perform some other kind of
>recovery operation.
>
>BUG_ON() is bad and is only to ever be used when the kernel's
>continued operation is absolutely impossible.

Fair enough. Will change.