kernel: DSA roaming fix for Marvell mv88e6xxx

Marvell mv88e6xxx switch series cannot perform MAC learning from
CPU-injected (FROM_CPU) DSA frames, which results in 2 issues.
- excessive flooding, due to the fact that DSA treats those addresses
as unknown
- the risk of stale routes, which can lead to temporary packet loss

Backport those patch series from netdev mailing list, which solve these
issues by adding and clearing static entries to the switch's FDB.

Add a hack patch to set default VID to 1 in port_fdb_{add,del}. Otherwise
the static entries will be added to the switch's private FDB if VLAN
filtering disabled, which will not work.

The switch may generate an "ATU violation" warning when a client moves
from the CPU port to a switch port because the static ATU entry added by
DSA core still points to the CPU port. DSA core will then clear the static
entry so it is not fatal. Disable the warning so it will not confuse users.

Link: https://lore.kernel.org/netdev/20210106095136.224739-1-olteanv@gmail.com/
Link: https://lore.kernel.org/netdev/20210116012515.3152-1-tobias@waldekranz.com/
Ref: https://gitlab.nic.cz/turris/turris-build/-/issues/165
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
(cherry picked from commit 920eaab1d8179035d0ae1047e75cf9a50da6a6eb)

1 files changed, 94 insertions, 0 deletions

diff --git a/target/linux/generic/pending-5.4/764-net-bridge-switchdev-Send-FDB-notifications-for-host.patch b/target/linux/generic/pending-5.4/764-net-bridge-switchdev-Send-FDB-notifications-for-host.patch
new file mode 100644
index 0000000000..8b869dd8f3
--- /dev/null
+++ b/target/linux/generic/pending-5.4/764-net-bridge-switchdev-Send-FDB-notifications-for-host.patch
@@ -0,0 +1,94 @@
+From 2e50fd9322047253c327550b4485cf8761035a8c Mon Sep 17 00:00:00 2001
+From: Tobias Waldekranz <tobias@waldekranz.com>
+Date: Sat, 16 Jan 2021 02:25:11 +0100
+Subject: [PATCH] net: bridge: switchdev: Send FDB notifications for host
+ addresses
+
+Treat addresses added to the bridge itself in the same way as regular
+ports and send out a notification so that drivers may sync it down to
+the hardware FDB.
+
+Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
+---
+ net/bridge/br_fdb.c       |  4 ++--
+ net/bridge/br_private.h   |  7 ++++---
+ net/bridge/br_switchdev.c | 11 +++++------
+ 3 files changed, 11 insertions(+), 11 deletions(-)
+
+--- a/net/bridge/br_fdb.c
++++ b/net/bridge/br_fdb.c
+@@ -581,7 +581,7 @@ void br_fdb_update(struct net_bridge *br
+ 
+ 			/* fastpath: update of existing entry */
+ 			if (unlikely(source != fdb->dst && !fdb->is_sticky)) {
+-				br_switchdev_fdb_notify(fdb, RTM_DELNEIGH);
++				br_switchdev_fdb_notify(br, fdb, RTM_DELNEIGH);
+ 				fdb->dst = source;
+ 				fdb_modified = true;
+ 				/* Take over HW learned entry */
+@@ -697,7 +697,7 @@ static void fdb_notify(struct net_bridge
+ 	int err = -ENOBUFS;
+ 
+ 	if (swdev_notify)
+-		br_switchdev_fdb_notify(fdb, type);
++		br_switchdev_fdb_notify(br, fdb, type);
+ 
+ 	skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
+ 	if (skb == NULL)
+--- a/net/bridge/br_private.h
++++ b/net/bridge/br_private.h
+@@ -1203,8 +1203,8 @@ bool nbp_switchdev_allowed_egress(const
+ int br_switchdev_set_port_flag(struct net_bridge_port *p,
+ 			       unsigned long flags,
+ 			       unsigned long mask);
+-void br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb,
+-			     int type);
++void br_switchdev_fdb_notify(struct net_bridge *br,
++			     const struct net_bridge_fdb_entry *fdb, int type);
+ int br_switchdev_port_vlan_add(struct net_device *dev, u16 vid, u16 flags,
+ 			       struct netlink_ext_ack *extack);
+ int br_switchdev_port_vlan_del(struct net_device *dev, u16 vid);
+@@ -1250,7 +1250,8 @@ static inline int br_switchdev_port_vlan
+ }
+ 
+ static inline void
+-br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
++br_switchdev_fdb_notify(struct net_bridge *br,
++			const struct net_bridge_fdb_entry *fdb, int type)
+ {
+ }
+ 
+--- a/net/bridge/br_switchdev.c
++++ b/net/bridge/br_switchdev.c
+@@ -103,7 +103,8 @@ int br_switchdev_set_port_flag(struct ne
+ }
+ 
+ void
+-br_switchdev_fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
++br_switchdev_fdb_notify(struct net_bridge *br,
++			const struct net_bridge_fdb_entry *fdb, int type)
+ {
+ 	struct switchdev_notifier_fdb_info info = {
+ 		.addr = fdb->key.addr.addr,
+@@ -112,18 +113,16 @@ br_switchdev_fdb_notify(const struct net
+ 		.local = fdb->is_local,
+ 		.offloaded = fdb->offloaded,
+ 	};
+-
+-	if (!fdb->dst)
+-		return;
++	struct net_device *dev = fdb->dst ? fdb->dst->dev : br->dev;
+ 
+ 	switch (type) {
+ 	case RTM_DELNEIGH:
+ 		call_switchdev_notifiers(SWITCHDEV_FDB_DEL_TO_DEVICE,
+-					 fdb->dst->dev, &info.info, NULL);
++					 dev, &info.info, NULL);
+ 		break;
+ 	case RTM_NEWNEIGH:
+ 		call_switchdev_notifiers(SWITCHDEV_FDB_ADD_TO_DEVICE,
+-					 fdb->dst->dev, &info.info, NULL);
++					 dev, &info.info, NULL);
+ 		break;
+ 	}
+ }