[PATCH v2 net-next 04/10] net: bridge: mst: Notify switchdev drivers of VLAN MSTI migrations

[Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>]

Whenever a VLAN moves to a new MSTI, send a switchdev notification so
that switchdevs can...

...either refuse the migration if the hardware does not support
offloading of MST...

..or track a bridge's VID to MSTI mapping when offloading is
supported.

Signed-off-by: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
---
 include/net/switchdev.h   | 10 +++++++
 net/bridge/br_mst.c       | 15 +++++++++++
 net/bridge/br_switchdev.c | 57 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 3e424d40fae3..39e57aa5005a 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -28,6 +28,7 @@ enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED,
 	SWITCHDEV_ATTR_ID_BRIDGE_MROUTER,
 	SWITCHDEV_ATTR_ID_MRP_PORT_ROLE,
+	SWITCHDEV_ATTR_ID_VLAN_MSTI,
 };
 
 struct switchdev_brport_flags {
@@ -35,6 +36,14 @@ struct switchdev_brport_flags {
 	unsigned long mask;
 };
 
+struct switchdev_vlan_attr {
+	u16 vid;
+
+	union {
+		u16 msti;
+	};
+};
+
 struct switchdev_attr {
 	struct net_device *orig_dev;
 	enum switchdev_attr_id id;
@@ -50,6 +59,7 @@ struct switchdev_attr {
 		u16 vlan_protocol;			/* BRIDGE_VLAN_PROTOCOL */
 		bool mc_disabled;			/* MC_DISABLED */
 		u8 mrp_port_role;			/* MRP_PORT_ROLE */
+		struct switchdev_vlan_attr vlan_attr;	/* VLAN_* */
 	} u;
 };
 
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 8dea8e7257fd..aba603675165 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/kernel.h>
+#include <net/switchdev.h>
 
 #include "br_private.h"
 
@@ -65,9 +66,23 @@ static void br_mst_vlan_sync_state(struct net_bridge_vlan *pv, u16 msti)
 
 int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)
 {
+	struct switchdev_attr attr = {
+		.id = SWITCHDEV_ATTR_ID_VLAN_MSTI,
+		.flags = SWITCHDEV_F_DEFER,
+		.orig_dev = mv->br->dev,
+		.u.vlan_attr = {
+			.vid = mv->vid,
+			.msti = msti,
+		},
+	};
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_vlan *pv;
 	struct net_bridge_port *p;
+	int err;
+
+	err = switchdev_port_attr_set(mv->br->dev, &attr, NULL);
+	if (err && err != -EOPNOTSUPP)
+		return err;
 
 	mv->msti = msti;
 
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index 6f6a70121a5e..160d7659f88a 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -428,6 +428,57 @@ static int br_switchdev_vlan_replay(struct net_device *br_dev,
 	return 0;
 }
 
+static int br_switchdev_mst_replay(struct net_device *br_dev,
+				   const void *ctx, bool adding,
+				   struct notifier_block *nb,
+				   struct netlink_ext_ack *extack)
+{
+	struct switchdev_notifier_port_attr_info attr_info = {
+		.info = {
+			.dev = br_dev,
+			.extack = extack,
+			.ctx = ctx,
+		},
+	};
+	struct net_bridge *br = netdev_priv(br_dev);
+	struct net_bridge_vlan_group *vg;
+	struct net_bridge_vlan *v;
+	int err;
+
+	ASSERT_RTNL();
+
+	if (!nb)
+		return 0;
+
+	if (!netif_is_bridge_master(br_dev))
+		return -EINVAL;
+
+	vg = br_vlan_group(br);
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		struct switchdev_attr attr = {
+			.id = SWITCHDEV_ATTR_ID_VLAN_MSTI,
+			.flags = SWITCHDEV_F_DEFER,
+			.orig_dev = br_dev,
+			.u.vlan_attr = {
+				.vid = v->vid,
+				.msti = v->msti,
+			}
+		};
+
+		if (!v->msti)
+			continue;
+
+		attr_info.attr = &attr;
+		err = nb->notifier_call(nb, SWITCHDEV_PORT_ATTR_SET, &attr_info);
+		err = notifier_to_errno(err);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 struct br_switchdev_mdb_complete_info {
 	struct net_bridge_port *port;
@@ -695,6 +746,10 @@ static int nbp_switchdev_sync_objs(struct net_bridge_port *p, const void *ctx,
 	if (err && err != -EOPNOTSUPP)
 		return err;
 
+	err = br_switchdev_mst_replay(br_dev, ctx, true, blocking_nb, extack);
+	if (err && err != -EOPNOTSUPP)
+		return err;
+
 	err = br_switchdev_mdb_replay(br_dev, dev, ctx, true, blocking_nb,
 				      extack);
 	if (err && err != -EOPNOTSUPP)
@@ -719,6 +774,8 @@ static void nbp_switchdev_unsync_objs(struct net_bridge_port *p,
 
 	br_switchdev_mdb_replay(br_dev, dev, ctx, false, blocking_nb, NULL);
 
+	br_switchdev_mst_replay(br_dev, ctx, false, blocking_nb, NULL);
+
 	br_switchdev_vlan_replay(br_dev, ctx, false, blocking_nb, NULL);
 }
 
-- 
2.25.1