Re: [PATCH net-next] bonding: 3ad: send rtnl ifinfo notify when mux state changed

[Nikolay Aleksandrov <razor@blackwall.org>]

On 6/20/24 09:10, Hangbin Liu wrote:
> Currently, administrators need to retrieve LACP mux state changes from
> the kernel DEBUG log using netdev_dbg and slave_dbg macros. To simplify
> this process, let's send the ifinfo notification whenever the mux state
> changes. This will enable users to directly access and monitor this
> information using the ip monitor command.
> 
> To achieve this, add a new enum NETDEV_LACP_STATE_CHANGE in netdev_cmd.
> 
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
> 
> After this patch, we can see the following info with `ip -d monitor link`
> 
> 7: veth1@if6: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc noqueue master bond0 state UP group default
>     link/ether 02:0a:04:c2:d6:21 brd ff:ff:ff:ff:ff:ff link-netns b promiscuity 0 allmulti 0 minmtu 68 maxmtu 65535
>     veth
>     bond_slave state BACKUP mii_status UP ... ad_aggregator_id 1 ad_actor_oper_port_state 143 ad_actor_oper_port_state_str <active,short_timeout,aggregating,in_sync,expired> ad_partner_oper_port_state 55 ad_partner_oper_port_state_str <active,short_timeout,aggregating,collecting,distributing> ...
> 7: veth1@if6: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc noqueue master bond0 state UP group default
>     link/ether 02:0a:04:c2:d6:21 brd ff:ff:ff:ff:ff:ff link-netns b promiscuity 0 allmulti 0 minmtu 68 maxmtu 65535
>     veth
>     bond_slave state ACTIVE mii_status UP ... ad_aggregator_id 1 ad_actor_oper_port_state 79 ad_actor_oper_port_state_str <active,short_timeout,aggregating,in_sync,defaulted> ad_partner_oper_port_state 1 ad_partner_oper_port_state_str <active> ...
> 7: veth1@if6: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc noqueue master bond0 state UP group default
>     link/ether 02:0a:04:c2:d6:21 brd ff:ff:ff:ff:ff:ff link-netns b promiscuity 0 allmulti 0 minmtu 68 maxmtu 65535
>     veth
>     bond_slave state ACTIVE mii_status UP ... ad_aggregator_id 1 ad_actor_oper_port_state 63 ad_actor_oper_port_state_str <active,short_timeout,aggregating,in_sync,collecting,distributing> ad_partner_oper_port_state 63 ad_partner_oper_port_state_str <active,short_timeout,aggregating,in_sync,collecting,distributing> ...
> 
> ---
>  drivers/net/bonding/bond_3ad.c | 2 ++
>  include/linux/netdevice.h      | 1 +
>  net/core/dev.c                 | 2 +-
>  net/core/rtnetlink.c           | 1 +
>  4 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
> index c6807e473ab7..bcd8b16173f2 100644
> --- a/drivers/net/bonding/bond_3ad.c
> +++ b/drivers/net/bonding/bond_3ad.c
> @@ -1185,6 +1185,8 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
>  		default:
>  			break;
>  		}
> +
> +		call_netdevice_notifiers(NETDEV_LACP_STATE_CHANGE, port->slave->dev);
>  	}

This will cause sleeping while atomic because
ad_mux_machine() is called in atomic context (both rcu and bond mode
spinlock held with bh disabled) in bond_3ad_state_machine_handler().

Minor (and rather more personal pref) I'd split the addition of the new
event and adding its first user (bond) for separate review.

Cheers,
 Nik