Re: [PATCH v2 net-next 07/10] net: dsa: Pass MST state changes to driver

[Vladimir Oltean <olteanv@gmail.com>]

On Tue, Mar 01, 2022 at 11:03:18AM +0100, Tobias Waldekranz wrote:
> Add the usual trampoline functionality from the generic DSA layer down
> to the drivers for MST state changes.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
> ---
>  include/net/dsa.h  |  2 ++
>  net/dsa/dsa_priv.h |  2 ++
>  net/dsa/port.c     | 30 ++++++++++++++++++++++++++++++
>  net/dsa/slave.c    |  6 ++++++
>  4 files changed, 40 insertions(+)
> 
> diff --git a/include/net/dsa.h b/include/net/dsa.h
> index cc8acb01bd9b..096e6e3a8e1e 100644
> --- a/include/net/dsa.h
> +++ b/include/net/dsa.h
> @@ -943,6 +943,8 @@ struct dsa_switch_ops {
>  				     struct dsa_bridge bridge);
>  	void	(*port_stp_state_set)(struct dsa_switch *ds, int port,
>  				      u8 state);
> +	int	(*port_mst_state_set)(struct dsa_switch *ds, int port,
> +				      const struct switchdev_mst_state *state);
>  	void	(*port_fast_age)(struct dsa_switch *ds, int port);
>  	int	(*port_pre_bridge_flags)(struct dsa_switch *ds, int port,
>  					 struct switchdev_brport_flags flags,
> diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
> index 87ec0697e92e..a620e079ebc5 100644
> --- a/net/dsa/dsa_priv.h
> +++ b/net/dsa/dsa_priv.h
> @@ -198,6 +198,8 @@ static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
>  void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
>  			       const struct dsa_device_ops *tag_ops);
>  int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);
> +int dsa_port_set_mst_state(struct dsa_port *dp,
> +			   const struct switchdev_mst_state *state);
>  int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy);
>  int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy);
>  void dsa_port_disable_rt(struct dsa_port *dp);
> diff --git a/net/dsa/port.c b/net/dsa/port.c
> index 5f45cb7d70ba..26cfbc8ab499 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -108,6 +108,36 @@ int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age)
>  	return 0;
>  }
>  
> +int dsa_port_set_mst_state(struct dsa_port *dp,
> +			   const struct switchdev_mst_state *state)
> +{
> +	struct dsa_switch *ds = dp->ds;
> +	int err, port = dp->index;
> +
> +	if (!ds->ops->port_mst_state_set)
> +		return -EOPNOTSUPP;
> +
> +	err = ds->ops->port_mst_state_set(ds, port, state);
> +	if (err)
> +		return err;
> +
> +	if (!dsa_port_can_configure_learning(dp) || dp->learning) {
> +		switch (state->state) {
> +		case BR_STATE_DISABLED:
> +		case BR_STATE_BLOCKING:
> +		case BR_STATE_LISTENING:
> +			/* Ideally we would only fast age entries
> +			 * belonging to VLANs controlled by this
> +			 * MST.
> +			 */
> +			dsa_port_fast_age(dp);

Does mv88e6xxx support this? If it does, you might just as well
introduce another variant of ds->ops->port_fast_age() for an msti.

And since it is new code, you could require that drivers _do_ support
configuring learning before they could support MSTP. After all, we don't
want to keep legacy mechanisms in place forever.

> +			break;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static void dsa_port_set_state_now(struct dsa_port *dp, u8 state,
>  				   bool do_fast_age)
>  {
> diff --git a/net/dsa/slave.c b/net/dsa/slave.c
> index c6ffcd782b5a..32b006a5b778 100644
> --- a/net/dsa/slave.c
> +++ b/net/dsa/slave.c
> @@ -288,6 +288,12 @@ static int dsa_slave_port_attr_set(struct net_device *dev, const void *ctx,
>  
>  		ret = dsa_port_set_state(dp, attr->u.stp_state, true);
>  		break;
> +	case SWITCHDEV_ATTR_ID_PORT_MST_STATE:
> +		if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
> +			return -EOPNOTSUPP;
> +
> +		ret = dsa_port_set_mst_state(dp, &attr->u.mst_state);
> +		break;
>  	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
>  		if (!dsa_port_offloads_bridge_dev(dp, attr->orig_dev))
>  			return -EOPNOTSUPP;
> -- 
> 2.25.1
>