Re: [patch net-next v3 08/17] bridge: call netdev_sw_port_stp_update when bridge port STP status changes

Florian Fainelli
2014-11-25T22:20:18Z

On 25/11/14 07:58, Andy Gospodarek wrote:
> On Tue, Nov 25, 2014 at 11:28:39AM +0100, Jiri Pirko wrote:
>> From: Scott Feldman <sfeldma@gmail.com>
>>
>> To notify switch driver of change in STP state of bridge port, add new
>> .ndo op and provide switchdev wrapper func to call ndo op. Use it in bridge
>> code then.
>>
>> Signed-off-by: Scott Feldman <sfeldma@gmail.com>
>> Signed-off-by: Jiri Pirko <jiri@resnulli.us>

[snip]

>> #include "br_private.h"
>> #include "br_private_stp.h"
>> @@ -39,6 +40,7 @@ void br_log_state(const struct net_bridge_port *p)
>> void br_set_state(struct net_bridge_port *p, unsigned int state)
>> {
>> p->state = state;
>> + netdev_switch_port_stp_update(p->dev, state);
>
> The only thing that concerns me about this patch is the fact that there
> is nothing paying attention to the return code.
>
> This means if *something* in the driver fails to set the STP state we
> have no way to feed this information back to the user to let them know
> that their hardware isn't exactly functioning as we expect.

This typically translates into an actual HW register write in general
(writing the STP algorithm result per-port), so although they typically
don't fail in most HW transports, I so no harm in returning something
useful just in case.

Once you do this, feel free to add a:

Acked-by: Florian Fainelli <f.fainelli@gmail.com>

Thanks!

>
> I do not expect that this first set would provide full feedback to
> br_make_forwarding, br_make_blocking, etc, to allow spanning tree to
> properly deal with the failure (that change is fine to add later), but a
> short one-liner indicating that the call to the hardware failed would e
> good. What about something simple like this:
>
> void br_set_state(struct net_bridge_port *p, unsigned int state)
> {
> int ret;
> p->state = state;
> ret = netdev_switch_port_stp_update(p->dev, state);
> if (ret && ret != -EOPNOTSUPP)
> br_warn(br, "error setting offload STP state for interface %s\n",
> p->dev->name);
> }
>
>>
>> /* called under bridge lock */
>> diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
>> index 66973de..d162b21 100644
>> --- a/net/switchdev/switchdev.c
>> +++ b/net/switchdev/switchdev.c
>> @@ -31,3 +31,22 @@ int netdev_switch_parent_id_get(struct net_device *dev,
>> return ops->ndo_switch_parent_id_get(dev, psid);
>> }
>> EXPORT_SYMBOL(netdev_switch_parent_id_get);
>> +
>> +/**
>> + * netdev_switch_port_stp_update - Notify switch device port of STP
>> + * state change
>> + * @dev: port device
>> + * @state: port STP state
>> + *
>> + * Notify switch device port of bridge port STP state change.
>> + */
>> +int netdev_switch_port_stp_update(struct net_device *dev, u8 state)
>> +{
>> + const struct net_device_ops *ops = dev->netdev_ops;
>> +
>> + if (!ops->ndo_switch_port_stp_update)
>> + return -EOPNOTSUPP;
>> + WARN_ON(!ops->ndo_switch_parent_id_get);
>> + return ops->ndo_switch_port_stp_update(dev, state);
>> +}
>> +EXPORT_SYMBOL(netdev_switch_port_stp_update);
>> --
>> 1.9.3
>>