Re: [PATCH v5 net-next 10/15] net: dsa: Validate hardware support for MST

Vladimir Oltean
2022-03-16T16:00:03Z

On Wed, Mar 16, 2022 at 04:08:52PM +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@waldekranz.com>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

> net/dsa/dsa_priv.h | 2 ++
> net/dsa/port.c | 22 ++++++++++++++++++++++
> net/dsa/slave.c | 6 ++++++
> 3 files changed, 30 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..02214033cec0 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -321,6 +321,11 @@ static void dsa_port_bridge_destroy(struct dsa_port *dp,
> kfree(bridge);
> }
>
> +static bool dsa_port_supports_mst(struct dsa_port *dp)
> +{
> + return dsa_port_can_configure_learning(dp);
> +}
> +
> int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
> struct netlink_ext_ack *extack)
> {
> @@ -334,6 +339,9 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
> struct net_device *brport_dev;
> int err;
>
> + if (br_mst_enabled(br) && !dsa_port_supports_mst(dp))
> + return -EOPNOTSUPP;
> +
> /* Here the interface is already bridged. Reflect the current
> * configuration so that drivers can program their chips accordingly.
> */
> @@ -735,6 +743,20 @@ 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)
> +{
> + if (!on)
> + return 0;
> +
> + if (!dsa_port_supports_mst(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 f9cecda791d5..2e8f62476ce9 100644
> --- a/net/dsa/slave.c
> +++ b/net/dsa/slave.c
> @@ -464,6 +464,12 @@ 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
>