On Mon, Mar 14, 2022 at 10:52:26AM +0100, Tobias Waldekranz wrote:
> When joining a bridge where MST is enabled, we validate that the
> proper offloading support is in place, otherwise we fallback to
> software bridging.
>
> When then mode is changed on a bridge in which we are members, we
> refuse the change if offloading is not supported.
>
> At the moment we only check for configurable learning, but this will
> be further restricted as we support more MST related switchdev events.
>
> Signed-off-by: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
> ---
> net/dsa/dsa_priv.h | 2 ++
> net/dsa/port.c | 20 ++++++++++++++++++++
> net/dsa/slave.c | 6 ++++++
> 3 files changed, 28 insertions(+)
>
> diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
> index f20bdd8ea0a8..2aba420696ef 100644
> --- a/net/dsa/dsa_priv.h
> +++ b/net/dsa/dsa_priv.h
> @@ -234,6 +234,8 @@ int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
> struct netlink_ext_ack *extack);
> bool dsa_port_skip_vlan_configuration(struct dsa_port *dp);
> int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock);
> +int dsa_port_mst_enable(struct dsa_port *dp, bool on,
> + struct netlink_ext_ack *extack);
> int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu,
> bool targeted_match);
> int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
> diff --git a/net/dsa/port.c b/net/dsa/port.c
> index 58291df14cdb..1a17a0efa2fa 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -240,6 +240,10 @@ static int dsa_port_switchdev_sync_attrs(struct dsa_port *dp,
> if (err && err != -EOPNOTSUPP)
> return err;
>
> + err = dsa_port_mst_enable(dp, br_mst_enabled(br), extack);
> + if (err && err != -EOPNOTSUPP)
> + return err;
The "err && err != -EOPNOTSUPP" scheme is in place for compatibility
with drivers that don't all support the bridge port attributes, but used
to work prior to dsa_port_switchdev_sync_attrs()'s existence.
I don't think this scheme is necessary for dsa_port_mst_enable(), you
can just return -EOPNOTSUPP and remove the special handling for this code.
> +
> return 0;
> }
>
> @@ -735,6 +739,22 @@ int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock)
> return 0;
> }
>
> +int dsa_port_mst_enable(struct dsa_port *dp, bool on,
> + struct netlink_ext_ack *extack)
> +{
> + struct dsa_switch *ds = dp->ds;
> +
> + if (!on)
> + return 0;
> +
> + if (!dsa_port_can_configure_learning(dp)) {
> + NL_SET_ERR_MSG_MOD(extack, "Hardware does not support MST");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> int dsa_port_pre_bridge_flags(const struct dsa_port *dp,
> struct switchdev_brport_flags flags,
> struct netlink_ext_ack *extack)
> diff --git a/net/dsa/slave.c b/net/dsa/slave.c
> index a61a7c54af20..333f5702ea4f 100644
> --- a/net/dsa/slave.c
> +++ b/net/dsa/slave.c
> @@ -463,6 +463,12 @@ static int dsa_slave_port_attr_set(struct net_device *dev, const void *ctx,
>
> ret = dsa_port_ageing_time(dp, attr->u.ageing_time);
> break;
> + case SWITCHDEV_ATTR_ID_BRIDGE_MST:
> + if (!dsa_port_offloads_bridge_dev(dp, attr->orig_dev))
> + return -EOPNOTSUPP;
> +
> + ret = dsa_port_mst_enable(dp, attr->u.mst, extack);
> + break;
> case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
> if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
> return -EOPNOTSUPP;
> --
> 2.25.1
>
