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

Jiri Pirko
2014-11-25T16:53:12Z

Tue, Nov 25, 2014 at 04:58:32PM CET, gospo@cumulusnetworks.com 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>
>> ---
>> v2->v3:
>> -changed "sw" string to "switch" to avoid confusion
>> v1->v2:
>> -no change
>> ---
>> include/linux/netdevice.h | 5 +++++
>> include/net/switchdev.h | 7 +++++++
>> net/bridge/br_stp.c | 2 ++
>> net/switchdev/switchdev.c | 19 +++++++++++++++++++
>> 4 files changed, 33 insertions(+)
>>
>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>> index ce096dc..66cb64e 100644
>> --- a/include/linux/netdevice.h
>> +++ b/include/linux/netdevice.h
>> @@ -1024,6 +1024,9 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
>> * Called to get an ID of the switch chip this port is part of.
>> * If driver implements this, it indicates that it represents a port
>> * of a switch chip.
>> + * int (*ndo_switch_port_stp_update)(struct net_device *dev, u8 state);
>> + * Called to notify switch device port of bridge port STP
>> + * state change.
>> */
>> struct net_device_ops {
>> int (*ndo_init)(struct net_device *dev);
>> @@ -1180,6 +1183,8 @@ struct net_device_ops {
>> #ifdef CONFIG_NET_SWITCHDEV
>> int (*ndo_switch_parent_id_get)(struct net_device *dev,
>> struct netdev_phys_item_id *psid);
>> + int (*ndo_switch_port_stp_update)(struct net_device *dev,
>> + u8 state);
>> #endif
>> };
>>
>> diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>> index 7a52360..8a6d164 100644
>> --- a/include/net/switchdev.h
>> +++ b/include/net/switchdev.h
>> @@ -16,6 +16,7 @@
>>
>> int netdev_switch_parent_id_get(struct net_device *dev,
>> struct netdev_phys_item_id *psid);
>> +int netdev_switch_port_stp_update(struct net_device *dev, u8 state);
>>
>> #else
>>
>> @@ -25,6 +26,12 @@ static inline int netdev_switch_parent_id_get(struct net_device *dev,
>> return -EOPNOTSUPP;
>> }
>>
>> +static inline int netdev_switch_port_stp_update(struct net_device *dev,
>> + u8 state)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +
>> #endif
>>
>> #endif /* _LINUX_SWITCHDEV_H_ */
>> diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
>> index 2b047bc..35e016c 100644
>> --- a/net/bridge/br_stp.c
>> +++ b/net/bridge/br_stp.c
>> @@ -12,6 +12,7 @@
>> */
>> #include <linux/kernel.h>
>> #include <linux/rculist.h>
>> +#include <net/switchdev.h>
>>
>> #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.
>
>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);
>}

That makes sense. Will add this.

>
>>
>> /* 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
>>