Linux Ethernet Bridging - Jul 2021 - [Bridge] [PATCH v6 net-next 5/7] net: bridge: switchdev: let drivers inform which bridge ports are offloaded

On reception of an skb, the bridge checks if it was marked as 'already
forwarded in hardware' (checks if skb->offload_fwd_mark == 1), and if it
is, it assigns the source hardware domain of that skb based on the
hardware domain of the ingress port. Then during forwarding, it enforces
that the egress port must have a different hardware domain than the
ingress one (this is done in nbp_switchdev_allowed_egress).

Non-switchdev drivers don't report any physical switch id (neither
through devlink nor .ndo_get_port_parent_id), therefore the bridge
assigns them a hardware domain of 0, and packets coming from them will
always have skb->offload_fwd_mark = 0. So there aren't any restrictions.

Problems appear due to the fact that DSA would like to perform software
fallback for bonding and team interfaces that the physical switch cannot
offload.

       +-- br0 ---+
      / /   |      \
     / /    |       \
    /  |    |      bond0
   /   |    |     /    \
 swp0 swp1 swp2 swp3 swp4

There, it is desirable that the presence of swp3 and swp4 under a
non-offloaded LAG does not preclude us from doing hardware bridging
beteen swp0, swp1 and swp2. The bandwidth of the CPU is often times high
enough that software bridging between {swp0,swp1,swp2} and bond0 is not
impractical.

But this creates an impossible paradox given the current way in which
port hardware domains are assigned. When the driver receives a packet
from swp0 (say, due to flooding), it must set skb->offload_fwd_mark to
something.

- If we set it to 0, then the bridge will forward it towards swp1, swp2
  and bond0. But the switch has already forwarded it towards swp1 and
  swp2 (not to bond0, remember, that isn't offloaded, so as far as the
  switch is concerned, ports swp3 and swp4 are not looking up the FDB,
  and the entire bond0 is a destination that is strictly behind the
  CPU). But we don't want duplicated traffic towards swp1 and swp2, so
  it's not ok to set skb->offload_fwd_mark = 0.

- If we set it to 1, then the bridge will not forward the skb towards
  the ports with the same switchdev mark, i.e. not to swp1, swp2 and
  bond0. Towards swp1 and swp2 that's ok, but towards bond0? It should
  have forwarded the skb there.

So the real issue is that bond0 will be assigned the same hardware
domain as {swp0,swp1,swp2}, because the function that assigns hardware
domains to bridge ports, nbp_switchdev_add(), recurses through bond0's
lower interfaces until it finds something that implements devlink (calls
dev_get_port_parent_id with bool recurse = true). This is a problem
because the fact that bond0 can be offloaded by swp3 and swp4 in our
example is merely an assumption.

A solution is to give the bridge explicit hints as to what hardware
domain it should use for each port.

Currently, the bridging offload is very 'silent': a driver registers a
netdevice notifier, which is put on the netns's notifier chain, and
which sniffs around for NETDEV_CHANGEUPPER events where the upper is a
bridge, and the lower is an interface it knows about (one registered by
this driver, normally). Then, from within that notifier, it does a bunch
of stuff behind the bridge's back, without the bridge necessarily
knowing that there's somebody offloading that port. It looks like this:

     ip link set swp0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v
        call_netdevice_notifiers
                  |
                  v
       dsa_slave_netdevice_event
                  |
                  v
        oh, hey! it's for me!
                  |
                  v
           .port_bridge_join

What we do to solve the conundrum is to be less silent, and change the
switchdev drivers to present themselves to the bridge. Something like this:

     ip link set swp0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v                    bridge: Aye! I'll use this
        call_netdevice_notifiers           ^  ppid as the
                  |                        |  hardware domain for
                  v                        |  this port, and zero
       dsa_slave_netdevice_event           |  if I got nothing.
                  |                        |
                  v                        |
        oh, hey! it's for me!              |
                  |                        |
                  v                        |
           .port_bridge_join               |
                  |                        |
                  +------------------------+
             switchdev_bridge_port_offload(swp0, swp0)

Then stacked interfaces (like bond0 on top of swp3/swp4) would be
treated differently in DSA, depending on whether we can or cannot
offload them.

The offload case:

    ip link set bond0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v                    bridge: Aye! I'll use this
        call_netdevice_notifiers           ^  ppid as the
                  |                        |  switchdev mark for
                  v                        |        bond0.
       dsa_slave_netdevice_event           | Coincidentally (or not),
                  |                        | bond0 and swp0, swp1, swp2
                  v                        | all have the same switchdev
        hmm, it's not quite for me,        | mark now, since the ASIC
         but my driver has already         | is able to forward towards
           called .port_lag_join           | all these ports in hw.
          for it, because I have           |
      a port with dp->lag_dev == bond0.    |
                  |                        |
                  v                        |
           .port_bridge_join               |
           for swp3 and swp4               |
                  |                        |
                  +------------------------+
            switchdev_bridge_port_offload(bond0, swp3)
            switchdev_bridge_port_offload(bond0, swp4)

And the non-offload case:

    ip link set bond0 master br0
                  |
                  v
 br_add_if() calls netdev_master_upper_dev_link()
                  |
                  v                    bridge waiting:
        call_netdevice_notifiers           ^  huh, switchdev_bridge_port_offload
                  |                        |  wasn't called, okay, I'll
use a
                  v                        |  hwdom of zero for this one.
       dsa_slave_netdevice_event           :  Then packets received on swp0 will
                  |                        :  not be software-forwarded towards
                  v                        :  swp1, but they will towards bond0.
         it's not for me, but
       bond0 is an upper of swp3
      and swp4, but their dp->lag_dev
       is NULL because they couldn't
            offload it.

Basically we can draw the conclusion that the lowers of a bridge port
can come and go, so depending on the configuration of lowers for a
bridge port, it can dynamically toggle between offloaded and unoffloaded.
Therefore, we need an equivalent switchdev_bridge_port_unoffload too.

This patch changes the way any switchdev driver interacts with the
bridge. From now on, everybody needs to call switchdev_bridge_port_offload
and switchdev_bridge_port_unoffload, otherwise the bridge will treat the
port as non-offloaded and allow software flooding to other ports from
the same ASIC.

Note that these functions lay the ground for a more complex handshake
between switchdev drivers and the bridge in the future.

For drivers that will request a replay of the switchdev objects when
they offload and unoffload a bridge port (DSA, dpaa2-switch, ocelot), we
place the call to switchdev_bridge_port_unoffload() strategically inside
the NETDEV_PRECHANGEUPPER notifier's code path, and not inside
NETDEV_CHANGEUPPER. This is because the switchdev object replay helpers
need the netdev adjacency lists to be valid, and that is only true in
NETDEV_PRECHANGEUPPER.

Cc: Vadym Kochan <vkochan at marvell.com>
Cc: Taras Chornyi <tchornyi at marvell.com>
Cc: Ioana Ciornei <ioana.ciornei at nxp.com>
Cc: Lars Povlsen <lars.povlsen at microchip.com>
Cc: Steen Hegelund <Steen.Hegelund at microchip.com>
Cc: UNGLinuxDriver at microchip.com
Cc: Claudiu Manoil <claudiu.manoil at nxp.com>
Cc: Alexandre Belloni <alexandre.belloni at bootlin.com>
Cc: Grygorii Strashko <grygorii.strashko at ti.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
Tested-by: Ioana Ciornei <ioana.ciornei at nxp.com> # dpaa2-switch:
regression
Acked-by: Ioana Ciornei <ioana.ciornei at nxp.com> # dpaa2-switch
Tested-by: Horatiu Vultur <horatiu.vultur at microchip.com> #
ocelot-switch
---
v2->v3: patch is new
v3->v4: added mlxsw_sp_port_pre_lag_leave() and
mlxsw_sp_port_pre_vlan_leave()
v4->v5: use for the comparison in nbp_switchdev_hwdom_set() the
        nbp->ppid provided by switchdev_bridge_port_offload() instead of
        recursing through the lower interfaces of the nbp->dev
v5->v6:
- add error handling to dpaa2-switch
- drop useless arguments from switchdev_bridge_port_unoffload(): dev,
  extack, and make it return void
- stop reworking as deeply the drivers where no replays will be
  requested for now, and just call the offload/unoffload helpers where
  it is most convenient.

 .../ethernet/freescale/dpaa2/dpaa2-switch.c   | 13 +++
 .../ethernet/marvell/prestera/prestera_main.c |  3 +-
 .../marvell/prestera/prestera_switchdev.c     | 11 ++-
 .../marvell/prestera/prestera_switchdev.h     |  3 +-
 .../mellanox/mlxsw/spectrum_switchdev.c       | 24 ++++--
 .../microchip/sparx5/sparx5_switchdev.c       | 23 +++++-
 drivers/net/ethernet/mscc/ocelot_net.c        | 71 ++++++++++++++++
 drivers/net/ethernet/rocker/rocker.h          |  3 +-
 drivers/net/ethernet/rocker/rocker_main.c     |  9 +-
 drivers/net/ethernet/rocker/rocker_ofdpa.c    | 18 +++-
 drivers/net/ethernet/ti/am65-cpsw-nuss.c      | 17 +++-
 drivers/net/ethernet/ti/cpsw_new.c            | 15 +++-
 include/linux/if_bridge.h                     | 21 +++++
 net/bridge/br_if.c                            | 13 +--
 net/bridge/br_private.h                       | 13 +--
 net/bridge/br_switchdev.c                     | 82 ++++++++++++++++---
 net/dsa/port.c                                | 16 +++-
 17 files changed, 298 insertions(+), 57 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
index 23798feb40b2..9b090da3e460 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
@@ -1930,8 +1930,13 @@ static int dpaa2_switch_port_bridge_join(struct
net_device *netdev,
 	if (err)
 		goto err_egress_flood;
 
+	err = switchdev_bridge_port_offload(netdev, netdev, extack);
+	if (err)
+		goto err_switchdev_offload;
+
 	return 0;
 
+err_switchdev_offload:
 err_egress_flood:
 	dpaa2_switch_port_set_fdb(port_priv, NULL);
 	return err;
@@ -1957,6 +1962,11 @@ static int dpaa2_switch_port_restore_rxvlan(struct
net_device *vdev, int vid, vo
 	return dpaa2_switch_port_vlan_add(arg, vlan_proto, vid);
 }
 
+static void dpaa2_switch_port_pre_bridge_leave(struct net_device *netdev)
+{
+	switchdev_bridge_port_unoffload(netdev);
+}
+
 static int dpaa2_switch_port_bridge_leave(struct net_device *netdev)
 {
 	struct ethsw_port_priv *port_priv = netdev_priv(netdev);
@@ -2078,6 +2088,9 @@ static int dpaa2_switch_port_netdevice_event(struct
notifier_block *nb,
 		if (err)
 			goto out;
 
+		if (!info->linking)
+			dpaa2_switch_port_pre_bridge_leave(netdev);
+
 		break;
 	case NETDEV_CHANGEUPPER:
 		upper_dev = info->upper_dev;
diff --git a/drivers/net/ethernet/marvell/prestera/prestera_main.c
b/drivers/net/ethernet/marvell/prestera/prestera_main.c
index 226f4ff29f6e..7c569c1abefc 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_main.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_main.c
@@ -746,7 +746,8 @@ static int prestera_netdev_port_event(struct net_device
*lower,
 	case NETDEV_CHANGEUPPER:
 		if (netif_is_bridge_master(upper)) {
 			if (info->linking)
-				return prestera_bridge_port_join(upper, port);
+				return prestera_bridge_port_join(upper, port,
+								 extack);
 			else
 				prestera_bridge_port_leave(upper, port);
 		} else if (netif_is_lag_master(upper)) {
diff --git a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
index 0b3e8f2db294..8cf3fe3b7e58 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
@@ -480,7 +480,8 @@ prestera_bridge_1d_port_join(struct prestera_bridge_port
*br_port)
 }
 
 int prestera_bridge_port_join(struct net_device *br_dev,
-			      struct prestera_port *port)
+			      struct prestera_port *port,
+			      struct netlink_ext_ack *extack)
 {
 	struct prestera_switchdev *swdev = port->sw->swdev;
 	struct prestera_bridge_port *br_port;
@@ -500,6 +501,10 @@ int prestera_bridge_port_join(struct net_device *br_dev,
 		goto err_brport_create;
 	}
 
+	err = switchdev_bridge_port_offload(br_port->dev, port->dev, extack);
+	if (err)
+		goto err_switchdev_offload;
+
 	if (bridge->vlan_enabled)
 		return 0;
 
@@ -510,6 +515,8 @@ int prestera_bridge_port_join(struct net_device *br_dev,
 	return 0;
 
 err_port_join:
+	switchdev_bridge_port_unoffload(br_port->dev);
+err_switchdev_offload:
 	prestera_bridge_port_put(br_port);
 err_brport_create:
 	prestera_bridge_put(bridge);
@@ -584,6 +591,8 @@ void prestera_bridge_port_leave(struct net_device *br_dev,
 	else
 		prestera_bridge_1d_port_leave(br_port);
 
+	switchdev_bridge_port_unoffload(br_port->dev);
+
 	prestera_hw_port_learning_set(port, false);
 	prestera_hw_port_flood_set(port, BR_FLOOD | BR_MCAST_FLOOD, 0);
 	prestera_port_vid_stp_set(port, PRESTERA_VID_ALL, BR_STATE_FORWARDING);
diff --git a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
index a91bc35d235f..0e93fda3d9a5 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
+++ b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
@@ -8,7 +8,8 @@ int prestera_switchdev_init(struct prestera_switch *sw);
 void prestera_switchdev_fini(struct prestera_switch *sw);
 
 int prestera_bridge_port_join(struct net_device *br_dev,
-			      struct prestera_port *port);
+			      struct prestera_port *port,
+			      struct netlink_ext_ack *extack);
 
 void prestera_bridge_port_leave(struct net_device *br_dev,
 				struct prestera_port *port);
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
index 61911fed6aeb..c52317de1f35 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
@@ -335,14 +335,16 @@ mlxsw_sp_bridge_port_find(struct mlxsw_sp_bridge *bridge,
 
 static struct mlxsw_sp_bridge_port *
 mlxsw_sp_bridge_port_create(struct mlxsw_sp_bridge_device *bridge_device,
-			    struct net_device *brport_dev)
+			    struct net_device *brport_dev,
+			    struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp_bridge_port *bridge_port;
 	struct mlxsw_sp_port *mlxsw_sp_port;
+	int err;
 
 	bridge_port = kzalloc(sizeof(*bridge_port), GFP_KERNEL);
 	if (!bridge_port)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	mlxsw_sp_port = mlxsw_sp_port_dev_lower_find(brport_dev);
 	bridge_port->lagged = mlxsw_sp_port->lagged;
@@ -359,12 +361,23 @@ mlxsw_sp_bridge_port_create(struct mlxsw_sp_bridge_device
*bridge_device,
 	list_add(&bridge_port->list, &bridge_device->ports_list);
 	bridge_port->ref_count = 1;
 
+	err = switchdev_bridge_port_offload(brport_dev, mlxsw_sp_port->dev,
+					    extack);
+	if (err)
+		goto err_switchdev_offload;
+
 	return bridge_port;
+
+err_switchdev_offload:
+	list_del(&bridge_port->list);
+	kfree(bridge_port);
+	return ERR_PTR(err);
 }
 
 static void
 mlxsw_sp_bridge_port_destroy(struct mlxsw_sp_bridge_port *bridge_port)
 {
+	switchdev_bridge_port_unoffload(bridge_port->dev);
 	list_del(&bridge_port->list);
 	WARN_ON(!list_empty(&bridge_port->vlans_list));
 	kfree(bridge_port);
@@ -390,9 +403,10 @@ mlxsw_sp_bridge_port_get(struct mlxsw_sp_bridge *bridge,
 	if (IS_ERR(bridge_device))
 		return ERR_CAST(bridge_device);
 
-	bridge_port = mlxsw_sp_bridge_port_create(bridge_device, brport_dev);
-	if (!bridge_port) {
-		err = -ENOMEM;
+	bridge_port = mlxsw_sp_bridge_port_create(bridge_device, brport_dev,
+						  extack);
+	if (IS_ERR(bridge_port)) {
+		err = PTR_ERR(bridge_port);
 		goto err_bridge_port_create;
 	}
 
diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
b/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
index a72e3b3b596e..e4fb573563d0 100644
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
@@ -93,9 +93,12 @@ static int sparx5_port_attr_set(struct net_device *dev, const
void *ctx,
 }
 
 static int sparx5_port_bridge_join(struct sparx5_port *port,
-				   struct net_device *bridge)
+				   struct net_device *bridge,
+				   struct netlink_ext_ack *extack)
 {
 	struct sparx5 *sparx5 = port->sparx5;
+	struct net_device *ndev = port->ndev;
+	int err;
 
 	if (bitmap_empty(sparx5->bridge_mask, SPX5_PORTS))
 		/* First bridged port */
@@ -109,12 +112,20 @@ static int sparx5_port_bridge_join(struct sparx5_port
*port,
 
 	set_bit(port->portno, sparx5->bridge_mask);
 
+	err = switchdev_bridge_port_offload(ndev, ndev, extack);
+	if (err)
+		goto err_switchdev_offload;
+
 	/* Port enters in bridge mode therefor don't need to copy to CPU
 	 * frames for multicast in case the bridge is not requesting them
 	 */
-	__dev_mc_unsync(port->ndev, sparx5_mc_unsync);
+	__dev_mc_unsync(ndev, sparx5_mc_unsync);
 
 	return 0;
+
+err_switchdev_offload:
+	clear_bit(port->portno, sparx5->bridge_mask);
+	return err;
 }
 
 static void sparx5_port_bridge_leave(struct sparx5_port *port,
@@ -122,6 +133,8 @@ static void sparx5_port_bridge_leave(struct sparx5_port
*port,
 {
 	struct sparx5 *sparx5 = port->sparx5;
 
+	switchdev_bridge_port_unoffload(port->ndev);
+
 	clear_bit(port->portno, sparx5->bridge_mask);
 	if (bitmap_empty(sparx5->bridge_mask, SPX5_PORTS))
 		sparx5->hw_bridge_dev = NULL;
@@ -139,11 +152,15 @@ static int sparx5_port_changeupper(struct net_device *dev,
 				   struct netdev_notifier_changeupper_info *info)
 {
 	struct sparx5_port *port = netdev_priv(dev);
+	struct netlink_ext_ack *extack;
 	int err = 0;
 
+	extack = netdev_notifier_info_to_extack(&info->info);
+
 	if (netif_is_bridge_master(info->upper_dev)) {
 		if (info->linking)
-			err = sparx5_port_bridge_join(port, info->upper_dev);
+			err = sparx5_port_bridge_join(port, info->upper_dev,
+						      extack);
 		else
 			sparx5_port_bridge_leave(port, info->upper_dev);
 
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c
b/drivers/net/ethernet/mscc/ocelot_net.c
index e9d260d84bf3..76b7b9536bf7 100644
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -1216,6 +1216,10 @@ static int ocelot_netdevice_bridge_join(struct net_device
*dev,
 
 	ocelot_port_bridge_join(ocelot, port, bridge);
 
+	err = switchdev_bridge_port_offload(brport_dev, dev, extack);
+	if (err)
+		goto err_switchdev_offload;
+
 	err = ocelot_switchdev_sync(ocelot, port, brport_dev, bridge, extack);
 	if (err)
 		goto err_switchdev_sync;
@@ -1223,10 +1227,17 @@ static int ocelot_netdevice_bridge_join(struct
net_device *dev,
 	return 0;
 
 err_switchdev_sync:
+	switchdev_bridge_port_unoffload(brport_dev);
+err_switchdev_offload:
 	ocelot_port_bridge_leave(ocelot, port, bridge);
 	return err;
 }
 
+static void ocelot_netdevice_pre_bridge_leave(struct net_device *brport_dev)
+{
+	switchdev_bridge_port_unoffload(brport_dev);
+}
+
 static int ocelot_netdevice_bridge_leave(struct net_device *dev,
 					 struct net_device *brport_dev,
 					 struct net_device *bridge)
@@ -1279,6 +1290,18 @@ static int ocelot_netdevice_lag_join(struct net_device
*dev,
 	return err;
 }
 
+static void ocelot_netdevice_pre_lag_leave(struct net_device *dev,
+					   struct net_device *bond)
+{
+	struct net_device *bridge_dev;
+
+	bridge_dev = netdev_master_upper_dev_get(bond);
+	if (!bridge_dev || !netif_is_bridge_master(bridge_dev))
+		return;
+
+	ocelot_netdevice_pre_bridge_leave(bond);
+}
+
 static int ocelot_netdevice_lag_leave(struct net_device *dev,
 				      struct net_device *bond)
 {
@@ -1355,6 +1378,43 @@ ocelot_netdevice_lag_changeupper(struct net_device *dev,
 	return NOTIFY_DONE;
 }
 
+static int
+ocelot_netdevice_prechangeupper(struct net_device *dev,
+				struct net_device *brport_dev,
+				struct netdev_notifier_changeupper_info *info)
+{
+	if (netif_is_bridge_master(info->upper_dev) && !info->linking)
+		ocelot_netdevice_pre_bridge_leave(brport_dev);
+
+	if (netif_is_lag_master(info->upper_dev) && !info->linking)
+		ocelot_netdevice_pre_lag_leave(dev, info->upper_dev);
+
+	return NOTIFY_DONE;
+}
+
+static int
+ocelot_netdevice_lag_prechangeupper(struct net_device *dev,
+				    struct netdev_notifier_changeupper_info *info)
+{
+	struct net_device *lower;
+	struct list_head *iter;
+	int err = NOTIFY_DONE;
+
+	netdev_for_each_lower_dev(dev, lower, iter) {
+		struct ocelot_port_private *priv = netdev_priv(lower);
+		struct ocelot_port *ocelot_port = &priv->port;
+
+		if (ocelot_port->bond != dev)
+			return NOTIFY_OK;
+
+		err = ocelot_netdevice_prechangeupper(dev, lower, info);
+		if (err)
+			return err;
+	}
+
+	return NOTIFY_DONE;
+}
+
 static int
 ocelot_netdevice_changelowerstate(struct net_device *dev,
 				  struct netdev_lag_lower_state_info *info)
@@ -1382,6 +1442,17 @@ static int ocelot_netdevice_event(struct notifier_block
*unused,
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
 	switch (event) {
+	case NETDEV_PRECHANGEUPPER: {
+		struct netdev_notifier_changeupper_info *info = ptr;
+
+		if (ocelot_netdevice_dev_check(dev))
+			return ocelot_netdevice_prechangeupper(dev, dev, info);
+
+		if (netif_is_lag_master(dev))
+			return ocelot_netdevice_lag_prechangeupper(dev, info);
+
+		break;
+	}
 	case NETDEV_CHANGEUPPER: {
 		struct netdev_notifier_changeupper_info *info = ptr;
 
diff --git a/drivers/net/ethernet/rocker/rocker.h
b/drivers/net/ethernet/rocker/rocker.h
index 315a6e5c0f59..e75814a4654f 100644
--- a/drivers/net/ethernet/rocker/rocker.h
+++ b/drivers/net/ethernet/rocker/rocker.h
@@ -119,7 +119,8 @@ struct rocker_world_ops {
 	int (*port_obj_fdb_del)(struct rocker_port *rocker_port,
 				u16 vid, const unsigned char *addr);
 	int (*port_master_linked)(struct rocker_port *rocker_port,
-				  struct net_device *master);
+				  struct net_device *master,
+				  struct netlink_ext_ack *extack);
 	int (*port_master_unlinked)(struct rocker_port *rocker_port,
 				    struct net_device *master);
 	int (*port_neigh_update)(struct rocker_port *rocker_port,
diff --git a/drivers/net/ethernet/rocker/rocker_main.c
b/drivers/net/ethernet/rocker/rocker_main.c
index a46633606cae..53d407a5dbf7 100644
--- a/drivers/net/ethernet/rocker/rocker_main.c
+++ b/drivers/net/ethernet/rocker/rocker_main.c
@@ -1670,13 +1670,14 @@ rocker_world_port_fdb_del(struct rocker_port
*rocker_port,
 }
 
 static int rocker_world_port_master_linked(struct rocker_port *rocker_port,
-					   struct net_device *master)
+					   struct net_device *master,
+					   struct netlink_ext_ack *extack)
 {
 	struct rocker_world_ops *wops = rocker_port->rocker->wops;
 
 	if (!wops->port_master_linked)
 		return -EOPNOTSUPP;
-	return wops->port_master_linked(rocker_port, master);
+	return wops->port_master_linked(rocker_port, master, extack);
 }
 
 static int rocker_world_port_master_unlinked(struct rocker_port *rocker_port,
@@ -3107,6 +3108,7 @@ struct rocker_port *rocker_port_dev_lower_find(struct
net_device *dev,
 static int rocker_netdevice_event(struct notifier_block *unused,
 				  unsigned long event, void *ptr)
 {
+	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct netdev_notifier_changeupper_info *info;
 	struct rocker_port *rocker_port;
@@ -3123,7 +3125,8 @@ static int rocker_netdevice_event(struct notifier_block
*unused,
 		rocker_port = netdev_priv(dev);
 		if (info->linking) {
 			err = rocker_world_port_master_linked(rocker_port,
-							      info->upper_dev);
+							      info->upper_dev,
+							      extack);
 			if (err)
 				netdev_warn(dev, "failed to reflect master linked (err %d)\n",
 					    err);
diff --git a/drivers/net/ethernet/rocker/rocker_ofdpa.c
b/drivers/net/ethernet/rocker/rocker_ofdpa.c
index 967a634ee9ac..84dcaf8687a0 100644
--- a/drivers/net/ethernet/rocker/rocker_ofdpa.c
+++ b/drivers/net/ethernet/rocker/rocker_ofdpa.c
@@ -2571,8 +2571,10 @@ static int ofdpa_port_obj_fdb_del(struct rocker_port
*rocker_port,
 }
 
 static int ofdpa_port_bridge_join(struct ofdpa_port *ofdpa_port,
-				  struct net_device *bridge)
+				  struct net_device *bridge,
+				  struct netlink_ext_ack *extack)
 {
+	struct net_device *dev = ofdpa_port->dev;
 	int err;
 
 	/* Port is joining bridge, so the internal VLAN for the
@@ -2592,13 +2594,20 @@ static int ofdpa_port_bridge_join(struct ofdpa_port
*ofdpa_port,
 
 	ofdpa_port->bridge_dev = bridge;
 
-	return ofdpa_port_vlan_add(ofdpa_port, OFDPA_UNTAGGED_VID, 0);
+	err = ofdpa_port_vlan_add(ofdpa_port, OFDPA_UNTAGGED_VID, 0);
+	if (err)
+		return err;
+
+	return switchdev_bridge_port_offload(dev, dev, extack);
 }
 
 static int ofdpa_port_bridge_leave(struct ofdpa_port *ofdpa_port)
 {
+	struct net_device *dev = ofdpa_port->dev;
 	int err;
 
+	switchdev_bridge_port_unoffload(dev);
+
 	err = ofdpa_port_vlan_del(ofdpa_port, OFDPA_UNTAGGED_VID, 0);
 	if (err)
 		return err;
@@ -2637,13 +2646,14 @@ static int ofdpa_port_ovs_changed(struct ofdpa_port
*ofdpa_port,
 }
 
 static int ofdpa_port_master_linked(struct rocker_port *rocker_port,
-				    struct net_device *master)
+				    struct net_device *master,
+				    struct netlink_ext_ack *extack)
 {
 	struct ofdpa_port *ofdpa_port = rocker_port->wpriv;
 	int err = 0;
 
 	if (netif_is_bridge_master(master))
-		err = ofdpa_port_bridge_join(ofdpa_port, master);
+		err = ofdpa_port_bridge_join(ofdpa_port, master, extack);
 	else if (netif_is_ovs_master(master))
 		err = ofdpa_port_ovs_changed(ofdpa_port, master);
 	return err;
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 718539cdd2f2..8b9596eb808e 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -7,6 +7,7 @@
 
 #include <linux/clk.h>
 #include <linux/etherdevice.h>
+#include <linux/if_bridge.h>
 #include <linux/if_vlan.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -2077,10 +2078,13 @@ bool am65_cpsw_port_dev_check(const struct net_device
*ndev)
 	return false;
 }
 
-static int am65_cpsw_netdevice_port_link(struct net_device *ndev, struct
net_device *br_ndev)
+static int am65_cpsw_netdevice_port_link(struct net_device *ndev,
+					 struct net_device *br_ndev,
+					 struct netlink_ext_ack *extack)
 {
 	struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
 	struct am65_cpsw_ndev_priv *priv = am65_ndev_to_priv(ndev);
+	int err;
 
 	if (!common->br_members) {
 		common->hw_bridge_dev = br_ndev;
@@ -2092,6 +2096,10 @@ static int am65_cpsw_netdevice_port_link(struct
net_device *ndev, struct net_dev
 			return -EOPNOTSUPP;
 	}
 
+	err = switchdev_bridge_port_offload(ndev, ndev, extack);
+	if (err)
+		return err;
+
 	common->br_members |= BIT(priv->port->port_id);
 
 	am65_cpsw_port_offload_fwd_mark_update(common);
@@ -2104,6 +2112,8 @@ static void am65_cpsw_netdevice_port_unlink(struct
net_device *ndev)
 	struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
 	struct am65_cpsw_ndev_priv *priv = am65_ndev_to_priv(ndev);
 
+	switchdev_bridge_port_unoffload(ndev);
+
 	common->br_members &= ~BIT(priv->port->port_id);
 
 	am65_cpsw_port_offload_fwd_mark_update(common);
@@ -2116,6 +2126,7 @@ static void am65_cpsw_netdevice_port_unlink(struct
net_device *ndev)
 static int am65_cpsw_netdevice_event(struct notifier_block *unused,
 				     unsigned long event, void *ptr)
 {
+	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
 	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
 	struct netdev_notifier_changeupper_info *info;
 	int ret = NOTIFY_DONE;
@@ -2129,7 +2140,9 @@ static int am65_cpsw_netdevice_event(struct notifier_block
*unused,
 
 		if (netif_is_bridge_master(info->upper_dev)) {
 			if (info->linking)
-				ret = am65_cpsw_netdevice_port_link(ndev, info->upper_dev);
+				ret = am65_cpsw_netdevice_port_link(ndev,
+								    info->upper_dev,
+								    extack);
 			else
 				am65_cpsw_netdevice_port_unlink(ndev);
 		}
diff --git a/drivers/net/ethernet/ti/cpsw_new.c
b/drivers/net/ethernet/ti/cpsw_new.c
index 57d279fdcc9f..bf9cadfb11b5 100644
--- a/drivers/net/ethernet/ti/cpsw_new.c
+++ b/drivers/net/ethernet/ti/cpsw_new.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/irqreturn.h>
 #include <linux/interrupt.h>
+#include <linux/if_bridge.h>
 #include <linux/if_ether.h>
 #include <linux/etherdevice.h>
 #include <linux/net_tstamp.h>
@@ -1499,10 +1500,12 @@ static void cpsw_port_offload_fwd_mark_update(struct
cpsw_common *cpsw)
 }
 
 static int cpsw_netdevice_port_link(struct net_device *ndev,
-				    struct net_device *br_ndev)
+				    struct net_device *br_ndev,
+				    struct netlink_ext_ack *extack)
 {
 	struct cpsw_priv *priv = netdev_priv(ndev);
 	struct cpsw_common *cpsw = priv->cpsw;
+	int err;
 
 	if (!cpsw->br_members) {
 		cpsw->hw_bridge_dev = br_ndev;
@@ -1514,6 +1517,10 @@ static int cpsw_netdevice_port_link(struct net_device
*ndev,
 			return -EOPNOTSUPP;
 	}
 
+	err = switchdev_bridge_port_offload(ndev, ndev, extack);
+	if (err)
+		return err;
+
 	cpsw->br_members |= BIT(priv->emac_port);
 
 	cpsw_port_offload_fwd_mark_update(cpsw);
@@ -1526,6 +1533,8 @@ static void cpsw_netdevice_port_unlink(struct net_device
*ndev)
 	struct cpsw_priv *priv = netdev_priv(ndev);
 	struct cpsw_common *cpsw = priv->cpsw;
 
+	switchdev_bridge_port_unoffload(ndev);
+
 	cpsw->br_members &= ~BIT(priv->emac_port);
 
 	cpsw_port_offload_fwd_mark_update(cpsw);
@@ -1538,6 +1547,7 @@ static void cpsw_netdevice_port_unlink(struct net_device
*ndev)
 static int cpsw_netdevice_event(struct notifier_block *unused,
 				unsigned long event, void *ptr)
 {
+	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
 	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
 	struct netdev_notifier_changeupper_info *info;
 	int ret = NOTIFY_DONE;
@@ -1552,7 +1562,8 @@ static int cpsw_netdevice_event(struct notifier_block
*unused,
 		if (netif_is_bridge_master(info->upper_dev)) {
 			if (info->linking)
 				ret = cpsw_netdevice_port_link(ndev,
-							       info->upper_dev);
+							       info->upper_dev,
+							       extack);
 			else
 				cpsw_netdevice_port_unlink(ndev);
 		}
diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index b651c5e32a28..ce413eca527e 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -206,4 +206,25 @@ static inline int br_fdb_replay(const struct net_device
*br_dev,
 }
 #endif
 
+#if IS_ENABLED(CONFIG_BRIDGE) && IS_ENABLED(CONFIG_NET_SWITCHDEV)
+
+int switchdev_bridge_port_offload(struct net_device *brport_dev,
+				  struct net_device *dev,
+				  struct netlink_ext_ack *extack);
+void switchdev_bridge_port_unoffload(struct net_device *brport_dev);
+
+#else
+
+static inline int switchdev_bridge_port_offload(struct net_device *brport_dev,
+						struct net_device *dev,
+						struct netlink_ext_ack *extack)
+{
+	return -EINVAL;
+}
+
+static inline void switchdev_bridge_port_unoffload(struct net_device
*brport_dev)
+{
+}
+#endif
+
 #endif
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index c0df50e4abbb..86f6d7e93ea8 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -349,7 +349,6 @@ static void del_nbp(struct net_bridge_port *p)
 	nbp_backup_clear(p);
 
 	nbp_update_port_count(br);
-	nbp_switchdev_del(p);
 
 	netdev_upper_dev_unlink(dev, br->dev);
 
@@ -644,10 +643,6 @@ int br_add_if(struct net_bridge *br, struct net_device
*dev,
 	if (err)
 		goto err5;
 
-	err = nbp_switchdev_add(p);
-	if (err)
-		goto err6;
-
 	dev_disable_lro(dev);
 
 	list_add_rcu(&p->list, &br->port_list);
@@ -685,13 +680,13 @@ int br_add_if(struct net_bridge *br, struct net_device
*dev,
 		 */
 		err = dev_pre_changeaddr_notify(br->dev, dev->dev_addr, extack);
 		if (err)
-			goto err7;
+			goto err6;
 	}
 
 	err = nbp_vlan_init(p, extack);
 	if (err) {
 		netdev_err(dev, "failed to initialize vlan filtering on this
port\n");
-		goto err7;
+		goto err6;
 	}
 
 	spin_lock_bh(&br->lock);
@@ -714,14 +709,12 @@ int br_add_if(struct net_bridge *br, struct net_device
*dev,
 
 	return 0;
 
-err7:
+err6:
 	if (fdb_synced)
 		br_fdb_unsync_static(br, p);
 	list_del_rcu(&p->list);
 	br_fdb_delete_by_port(br, p, 0, 1);
 	nbp_update_port_count(br);
-	nbp_switchdev_del(p);
-err6:
 	netdev_upper_dev_unlink(dev, br->dev);
 err5:
 	dev->priv_flags &= ~IFF_BRIDGE_PORT;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 1c1732d7212a..8d2e4d807808 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -392,6 +392,8 @@ struct net_bridge_port {
 	 * hardware domain.
 	 */
 	int				hwdom;
+	int				offload_count;
+	struct netdev_phys_item_id	ppid;
 #endif
 	u16				group_fwd_mask;
 	u16				backup_redirected_cnt;
@@ -1856,8 +1858,6 @@ void br_switchdev_fdb_notify(struct net_bridge *br,
 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);
-int nbp_switchdev_add(struct net_bridge_port *p);
-void nbp_switchdev_del(struct net_bridge_port *p);
 void br_switchdev_init(struct net_bridge *br);
 
 static inline void br_switchdev_frame_unmark(struct sk_buff *skb)
@@ -1906,15 +1906,6 @@ static inline void br_switchdev_frame_unmark(struct
sk_buff *skb)
 {
 }
 
-static inline int nbp_switchdev_add(struct net_bridge_port *p)
-{
-	return 0;
-}
-
-static inline void nbp_switchdev_del(struct net_bridge_port *p)
-{
-}
-
 static inline void br_switchdev_init(struct net_bridge *br)
 {
 }
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index f3120f13c293..39f0787fde01 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -133,7 +133,7 @@ static int nbp_switchdev_hwdom_set(struct net_bridge_port
*joining)
 
 	/* joining is yet to be added to the port list. */
 	list_for_each_entry(p, &br->port_list, list) {
-		if (netdev_port_same_parent_id(joining->dev, p->dev)) {
+		if (netdev_phys_item_id_same(&joining->ppid, &p->ppid)) {
 			joining->hwdom = p->hwdom;
 			return 0;
 		}
@@ -162,27 +162,85 @@ static void nbp_switchdev_hwdom_put(struct net_bridge_port
*leaving)
 	clear_bit(leaving->hwdom, &br->busy_hwdoms);
 }
 
-int nbp_switchdev_add(struct net_bridge_port *p)
+static int nbp_switchdev_add(struct net_bridge_port *p,
+			     struct netdev_phys_item_id ppid,
+			     struct netlink_ext_ack *extack)
 {
-	struct netdev_phys_item_id ppid = { };
-	int err;
+	if (p->offload_count) {
+		/* Prevent unsupported configurations such as a bridge port
+		 * which is a bonding interface, and the member ports are from
+		 * different hardware switches.
+		 */
+		if (!netdev_phys_item_id_same(&p->ppid, &ppid)) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Same bridge port cannot be offloaded by two physical
switches");
+			return -EBUSY;
+		}
 
-	ASSERT_RTNL();
+		/* Tolerate drivers that call switchdev_bridge_port_offload()
+		 * more than once for the same bridge port, such as when the
+		 * bridge port is an offloaded bonding/team interface.
+		 */
+		p->offload_count++;
 
-	err = dev_get_port_parent_id(p->dev, &ppid, true);
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
+		return 0;
 	}
 
+	p->ppid = ppid;
+	p->offload_count = 1;
+
 	return nbp_switchdev_hwdom_set(p);
 }
 
-void nbp_switchdev_del(struct net_bridge_port *p)
+static void nbp_switchdev_del(struct net_bridge_port *p)
 {
-	ASSERT_RTNL();
+	if (WARN_ON(!p->offload_count))
+		return;
+
+	p->offload_count--;
+
+	if (p->offload_count)
+		return;
 
 	if (p->hwdom)
 		nbp_switchdev_hwdom_put(p);
 }
+
+/* Let the bridge know that this port is offloaded, so that it can assign a
+ * switchdev hardware domain to it.
+ */
+int switchdev_bridge_port_offload(struct net_device *brport_dev,
+				  struct net_device *dev,
+				  struct netlink_ext_ack *extack)
+{
+	struct netdev_phys_item_id ppid;
+	struct net_bridge_port *p;
+	int err;
+
+	ASSERT_RTNL();
+
+	p = br_port_get_rtnl(brport_dev);
+	if (!p)
+		return -ENODEV;
+
+	err = dev_get_port_parent_id(dev, &ppid, false);
+	if (err)
+		return err;
+
+	return nbp_switchdev_add(p, ppid, extack);
+}
+EXPORT_SYMBOL_GPL(switchdev_bridge_port_offload);
+
+void switchdev_bridge_port_unoffload(struct net_device *brport_dev)
+{
+	struct net_bridge_port *p;
+
+	ASSERT_RTNL();
+
+	p = br_port_get_rtnl(brport_dev);
+	if (!p)
+		return;
+
+	nbp_switchdev_del(p);
+}
+EXPORT_SYMBOL_GPL(switchdev_bridge_port_unoffload);
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 982e18771d76..7accda066149 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -292,6 +292,8 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
 		.port = dp->index,
 		.br = br,
 	};
+	struct net_device *dev = dp->slave;
+	struct net_device *brport_dev;
 	int err;
 
 	/* Here the interface is already bridged. Reflect the current
@@ -299,16 +301,24 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
 	 */
 	dp->bridge_dev = br;
 
+	brport_dev = dsa_port_to_bridge_port(dp);
+
 	err = dsa_broadcast(DSA_NOTIFIER_BRIDGE_JOIN, &info);
 	if (err)
 		goto out_rollback;
 
-	err = dsa_port_switchdev_sync(dp, extack);
+	err = switchdev_bridge_port_offload(brport_dev, dev, extack);
 	if (err)
 		goto out_rollback_unbridge;
 
+	err = dsa_port_switchdev_sync(dp, extack);
+	if (err)
+		goto out_rollback_unoffload;
+
 	return 0;
 
+out_rollback_unoffload:
+	switchdev_bridge_port_unoffload(brport_dev);
 out_rollback_unbridge:
 	dsa_broadcast(DSA_NOTIFIER_BRIDGE_LEAVE, &info);
 out_rollback:
@@ -319,6 +329,10 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
 int dsa_port_pre_bridge_leave(struct dsa_port *dp, struct net_device *br,
 			      struct netlink_ext_ack *extack)
 {
+	struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
+
+	switchdev_bridge_port_unoffload(brport_dev);
+
 	return dsa_port_switchdev_unsync_objs(dp, br, extack);
 }
 
-- 
2.25.1

On Wed, 21 Jul 2021 at 21:56, Vladimir Oltean <vladimir.oltean at nxp.com>
wrote:
>
> On reception of an skb, the bridge checks if it was marked as 'already
> forwarded in hardware' (checks if skb->offload_fwd_mark == 1), and
if it
> is, it assigns the source hardware domain of that skb based on the
> hardware domain of the ingress port. Then during forwarding, it enforces
> that the egress port must have a different hardware domain than the
> ingress one (this is done in nbp_switchdev_allowed_egress).
>
> Non-switchdev drivers don't report any physical switch id (neither
> through devlink nor .ndo_get_port_parent_id), therefore the bridge
> assigns them a hardware domain of 0, and packets coming from them will
> always have skb->offload_fwd_mark = 0. So there aren't any
restrictions.
>
> Problems appear due to the fact that DSA would like to perform software
> fallback for bonding and team interfaces that the physical switch cannot
> offload.
>
>        +-- br0 ---+
>       / /   |      \
>      / /    |       \
>     /  |    |      bond0
>    /   |    |     /    \
>  swp0 swp1 swp2 swp3 swp4
>
> There, it is desirable that the presence of swp3 and swp4 under a
> non-offloaded LAG does not preclude us from doing hardware bridging
> beteen swp0, swp1 and swp2. The bandwidth of the CPU is often times high
> enough that software bridging between {swp0,swp1,swp2} and bond0 is not
> impractical.
>
> But this creates an impossible paradox given the current way in which
> port hardware domains are assigned. When the driver receives a packet
> from swp0 (say, due to flooding), it must set skb->offload_fwd_mark to
> something.
>
> - If we set it to 0, then the bridge will forward it towards swp1, swp2
>   and bond0. But the switch has already forwarded it towards swp1 and
>   swp2 (not to bond0, remember, that isn't offloaded, so as far as the
>   switch is concerned, ports swp3 and swp4 are not looking up the FDB,
>   and the entire bond0 is a destination that is strictly behind the
>   CPU). But we don't want duplicated traffic towards swp1 and swp2, so
>   it's not ok to set skb->offload_fwd_mark = 0.
>
> - If we set it to 1, then the bridge will not forward the skb towards
>   the ports with the same switchdev mark, i.e. not to swp1, swp2 and
>   bond0. Towards swp1 and swp2 that's ok, but towards bond0? It should
>   have forwarded the skb there.
>
> So the real issue is that bond0 will be assigned the same hardware
> domain as {swp0,swp1,swp2}, because the function that assigns hardware
> domains to bridge ports, nbp_switchdev_add(), recurses through bond0's
> lower interfaces until it finds something that implements devlink (calls
> dev_get_port_parent_id with bool recurse = true). This is a problem
> because the fact that bond0 can be offloaded by swp3 and swp4 in our
> example is merely an assumption.
>
> A solution is to give the bridge explicit hints as to what hardware
> domain it should use for each port.
>
> Currently, the bridging offload is very 'silent': a driver
registers a
> netdevice notifier, which is put on the netns's notifier chain, and
> which sniffs around for NETDEV_CHANGEUPPER events where the upper is a
> bridge, and the lower is an interface it knows about (one registered by
> this driver, normally). Then, from within that notifier, it does a bunch
> of stuff behind the bridge's back, without the bridge necessarily
> knowing that there's somebody offloading that port. It looks like this:
>
>      ip link set swp0 master br0
>                   |
>                   v
>  br_add_if() calls netdev_master_upper_dev_link()
>                   |
>                   v
>         call_netdevice_notifiers
>                   |
>                   v
>        dsa_slave_netdevice_event
>                   |
>                   v
>         oh, hey! it's for me!
>                   |
>                   v
>            .port_bridge_join
>
> What we do to solve the conundrum is to be less silent, and change the
> switchdev drivers to present themselves to the bridge. Something like this:
>
>      ip link set swp0 master br0
>                   |
>                   v
>  br_add_if() calls netdev_master_upper_dev_link()
>                   |
>                   v                    bridge: Aye! I'll use this
>         call_netdevice_notifiers           ^  ppid as the
>                   |                        |  hardware domain for
>                   v                        |  this port, and zero
>        dsa_slave_netdevice_event           |  if I got nothing.
>                   |                        |
>                   v                        |
>         oh, hey! it's for me!              |
>                   |                        |
>                   v                        |
>            .port_bridge_join               |
>                   |                        |
>                   +------------------------+
>              switchdev_bridge_port_offload(swp0, swp0)
>
> Then stacked interfaces (like bond0 on top of swp3/swp4) would be
> treated differently in DSA, depending on whether we can or cannot
> offload them.
>
> The offload case:
>
>     ip link set bond0 master br0
>                   |
>                   v
>  br_add_if() calls netdev_master_upper_dev_link()
>                   |
>                   v                    bridge: Aye! I'll use this
>         call_netdevice_notifiers           ^  ppid as the
>                   |                        |  switchdev mark for
>                   v                        |        bond0.
>        dsa_slave_netdevice_event           | Coincidentally (or not),
>                   |                        | bond0 and swp0, swp1, swp2
>                   v                        | all have the same switchdev
>         hmm, it's not quite for me,        | mark now, since the ASIC
>          but my driver has already         | is able to forward towards
>            called .port_lag_join           | all these ports in hw.
>           for it, because I have           |
>       a port with dp->lag_dev == bond0.    |
>                   |                        |
>                   v                        |
>            .port_bridge_join               |
>            for swp3 and swp4               |
>                   |                        |
>                   +------------------------+
>             switchdev_bridge_port_offload(bond0, swp3)
>             switchdev_bridge_port_offload(bond0, swp4)
>
> And the non-offload case:
>
>     ip link set bond0 master br0
>                   |
>                   v
>  br_add_if() calls netdev_master_upper_dev_link()
>                   |
>                   v                    bridge waiting:
>         call_netdevice_notifiers           ^  huh,
switchdev_bridge_port_offload
>                   |                        |  wasn't called, okay,
I'll use a
>                   v                        |  hwdom of zero for this one.
>        dsa_slave_netdevice_event           :  Then packets received on swp0
will
>                   |                        :  not be software-forwarded
towards
>                   v                        :  swp1, but they will towards
bond0.
>          it's not for me, but
>        bond0 is an upper of swp3
>       and swp4, but their dp->lag_dev
>        is NULL because they couldn't
>             offload it.
>
> Basically we can draw the conclusion that the lowers of a bridge port
> can come and go, so depending on the configuration of lowers for a
> bridge port, it can dynamically toggle between offloaded and unoffloaded.
> Therefore, we need an equivalent switchdev_bridge_port_unoffload too.
>
> This patch changes the way any switchdev driver interacts with the
> bridge. From now on, everybody needs to call switchdev_bridge_port_offload
> and switchdev_bridge_port_unoffload, otherwise the bridge will treat the
> port as non-offloaded and allow software flooding to other ports from
> the same ASIC.
>
> Note that these functions lay the ground for a more complex handshake
> between switchdev drivers and the bridge in the future.
>
> For drivers that will request a replay of the switchdev objects when
> they offload and unoffload a bridge port (DSA, dpaa2-switch, ocelot), we
> place the call to switchdev_bridge_port_unoffload() strategically inside
> the NETDEV_PRECHANGEUPPER notifier's code path, and not inside
> NETDEV_CHANGEUPPER. This is because the switchdev object replay helpers
> need the netdev adjacency lists to be valid, and that is only true in
> NETDEV_PRECHANGEUPPER.
>
> Cc: Vadym Kochan <vkochan at marvell.com>
> Cc: Taras Chornyi <tchornyi at marvell.com>
> Cc: Ioana Ciornei <ioana.ciornei at nxp.com>
> Cc: Lars Povlsen <lars.povlsen at microchip.com>
> Cc: Steen Hegelund <Steen.Hegelund at microchip.com>
> Cc: UNGLinuxDriver at microchip.com
> Cc: Claudiu Manoil <claudiu.manoil at nxp.com>
> Cc: Alexandre Belloni <alexandre.belloni at bootlin.com>
> Cc: Grygorii Strashko <grygorii.strashko at ti.com>
> Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
> Tested-by: Ioana Ciornei <ioana.ciornei at nxp.com> # dpaa2-switch:
regression
> Acked-by: Ioana Ciornei <ioana.ciornei at nxp.com> # dpaa2-switch
> Tested-by: Horatiu Vultur <horatiu.vultur at microchip.com> #
ocelot-switch
> ---
> v2->v3: patch is new
> v3->v4: added mlxsw_sp_port_pre_lag_leave() and
mlxsw_sp_port_pre_vlan_leave()
> v4->v5: use for the comparison in nbp_switchdev_hwdom_set() the
>         nbp->ppid provided by switchdev_bridge_port_offload() instead of
>         recursing through the lower interfaces of the nbp->dev
> v5->v6:
> - add error handling to dpaa2-switch
> - drop useless arguments from switchdev_bridge_port_unoffload(): dev,
>   extack, and make it return void
> - stop reworking as deeply the drivers where no replays will be
>   requested for now, and just call the offload/unoffload helpers where
>   it is most convenient.
>
>  .../ethernet/freescale/dpaa2/dpaa2-switch.c   | 13 +++
>  .../ethernet/marvell/prestera/prestera_main.c |  3 +-
>  .../marvell/prestera/prestera_switchdev.c     | 11 ++-
>  .../marvell/prestera/prestera_switchdev.h     |  3 +-
>  .../mellanox/mlxsw/spectrum_switchdev.c       | 24 ++++--
>  .../microchip/sparx5/sparx5_switchdev.c       | 23 +++++-
>  drivers/net/ethernet/mscc/ocelot_net.c        | 71 ++++++++++++++++
>  drivers/net/ethernet/rocker/rocker.h          |  3 +-
>  drivers/net/ethernet/rocker/rocker_main.c     |  9 +-
>  drivers/net/ethernet/rocker/rocker_ofdpa.c    | 18 +++-
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c      | 17 +++-
>  drivers/net/ethernet/ti/cpsw_new.c            | 15 +++-
>  include/linux/if_bridge.h                     | 21 +++++
>  net/bridge/br_if.c                            | 13 +--
>  net/bridge/br_private.h                       | 13 +--
>  net/bridge/br_switchdev.c                     | 82 ++++++++++++++++---
>  net/dsa/port.c                                | 16 +++-
>  17 files changed, 298 insertions(+), 57 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
> index 23798feb40b2..9b090da3e460 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
> @@ -1930,8 +1930,13 @@ static int dpaa2_switch_port_bridge_join(struct
net_device *netdev,
>         if (err)
>                 goto err_egress_flood;
>
> +       err = switchdev_bridge_port_offload(netdev, netdev, extack);
> +       if (err)
> +               goto err_switchdev_offload;
> +
>         return 0;
>
> +err_switchdev_offload:
>  err_egress_flood:
>         dpaa2_switch_port_set_fdb(port_priv, NULL);
>         return err;
> @@ -1957,6 +1962,11 @@ static int dpaa2_switch_port_restore_rxvlan(struct
net_device *vdev, int vid, vo
>         return dpaa2_switch_port_vlan_add(arg, vlan_proto, vid);
>  }
>
> +static void dpaa2_switch_port_pre_bridge_leave(struct net_device *netdev)
> +{
> +       switchdev_bridge_port_unoffload(netdev);
> +}
> +
>  static int dpaa2_switch_port_bridge_leave(struct net_device *netdev)
>  {
>         struct ethsw_port_priv *port_priv = netdev_priv(netdev);
> @@ -2078,6 +2088,9 @@ static int dpaa2_switch_port_netdevice_event(struct
notifier_block *nb,
>                 if (err)
>                         goto out;
>
> +               if (!info->linking)
> +                       dpaa2_switch_port_pre_bridge_leave(netdev);
> +
>                 break;
>         case NETDEV_CHANGEUPPER:
>                 upper_dev = info->upper_dev;
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_main.c
b/drivers/net/ethernet/marvell/prestera/prestera_main.c
> index 226f4ff29f6e..7c569c1abefc 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_main.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_main.c
> @@ -746,7 +746,8 @@ static int prestera_netdev_port_event(struct net_device
*lower,
>         case NETDEV_CHANGEUPPER:
>                 if (netif_is_bridge_master(upper)) {
>                         if (info->linking)
> -                               return prestera_bridge_port_join(upper,
port);
> +                               return prestera_bridge_port_join(upper,
port,
> +                                                                extack);
>                         else
>                                 prestera_bridge_port_leave(upper, port);
>                 } else if (netif_is_lag_master(upper)) {
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
> index 0b3e8f2db294..8cf3fe3b7e58 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
> @@ -480,7 +480,8 @@ prestera_bridge_1d_port_join(struct
prestera_bridge_port *br_port)
>  }
>
>  int prestera_bridge_port_join(struct net_device *br_dev,
> -                             struct prestera_port *port)
> +                             struct prestera_port *port,
> +                             struct netlink_ext_ack *extack)
>  {
>         struct prestera_switchdev *swdev = port->sw->swdev;
>         struct prestera_bridge_port *br_port;
> @@ -500,6 +501,10 @@ int prestera_bridge_port_join(struct net_device
*br_dev,
>                 goto err_brport_create;
>         }
>
> +       err = switchdev_bridge_port_offload(br_port->dev, port->dev,
extack);
> +       if (err)
> +               goto err_switchdev_offload;
> +
>         if (bridge->vlan_enabled)
>                 return 0;
>
> @@ -510,6 +515,8 @@ int prestera_bridge_port_join(struct net_device
*br_dev,
>         return 0;
>
>  err_port_join:
> +       switchdev_bridge_port_unoffload(br_port->dev);
> +err_switchdev_offload:
>         prestera_bridge_port_put(br_port);
>  err_brport_create:
>         prestera_bridge_put(bridge);
> @@ -584,6 +591,8 @@ void prestera_bridge_port_leave(struct net_device
*br_dev,
>         else
>                 prestera_bridge_1d_port_leave(br_port);
>
> +       switchdev_bridge_port_unoffload(br_port->dev);
> +
>         prestera_hw_port_learning_set(port, false);
>         prestera_hw_port_flood_set(port, BR_FLOOD | BR_MCAST_FLOOD, 0);
>         prestera_port_vid_stp_set(port, PRESTERA_VID_ALL,
BR_STATE_FORWARDING);
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
> index a91bc35d235f..0e93fda3d9a5 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.h
> @@ -8,7 +8,8 @@ int prestera_switchdev_init(struct prestera_switch *sw);
>  void prestera_switchdev_fini(struct prestera_switch *sw);
>
>  int prestera_bridge_port_join(struct net_device *br_dev,
> -                             struct prestera_port *port);
> +                             struct prestera_port *port,
> +                             struct netlink_ext_ack *extack);
>
>  void prestera_bridge_port_leave(struct net_device *br_dev,
>                                 struct prestera_port *port);
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
> index 61911fed6aeb..c52317de1f35 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
> @@ -335,14 +335,16 @@ mlxsw_sp_bridge_port_find(struct mlxsw_sp_bridge
*bridge,
>
>  static struct mlxsw_sp_bridge_port *
>  mlxsw_sp_bridge_port_create(struct mlxsw_sp_bridge_device *bridge_device,
> -                           struct net_device *brport_dev)
> +                           struct net_device *brport_dev,
> +                           struct netlink_ext_ack *extack)
>  {
>         struct mlxsw_sp_bridge_port *bridge_port;
>         struct mlxsw_sp_port *mlxsw_sp_port;
> +       int err;
>
>         bridge_port = kzalloc(sizeof(*bridge_port), GFP_KERNEL);
>         if (!bridge_port)
> -               return NULL;
> +               return ERR_PTR(-ENOMEM);
>
>         mlxsw_sp_port = mlxsw_sp_port_dev_lower_find(brport_dev);
>         bridge_port->lagged = mlxsw_sp_port->lagged;
> @@ -359,12 +361,23 @@ mlxsw_sp_bridge_port_create(struct
mlxsw_sp_bridge_device *bridge_device,
>         list_add(&bridge_port->list,
&bridge_device->ports_list);
>         bridge_port->ref_count = 1;
>
> +       err = switchdev_bridge_port_offload(brport_dev,
mlxsw_sp_port->dev,
> +                                           extack);
> +       if (err)
> +               goto err_switchdev_offload;
> +
>         return bridge_port;
> +
> +err_switchdev_offload:
> +       list_del(&bridge_port->list);
> +       kfree(bridge_port);
> +       return ERR_PTR(err);
>  }
>
>  static void
>  mlxsw_sp_bridge_port_destroy(struct mlxsw_sp_bridge_port *bridge_port)
>  {
> +       switchdev_bridge_port_unoffload(bridge_port->dev);
>         list_del(&bridge_port->list);
>         WARN_ON(!list_empty(&bridge_port->vlans_list));
>         kfree(bridge_port);
> @@ -390,9 +403,10 @@ mlxsw_sp_bridge_port_get(struct mlxsw_sp_bridge
*bridge,
>         if (IS_ERR(bridge_device))
>                 return ERR_CAST(bridge_device);
>
> -       bridge_port = mlxsw_sp_bridge_port_create(bridge_device,
brport_dev);
> -       if (!bridge_port) {
> -               err = -ENOMEM;
> +       bridge_port = mlxsw_sp_bridge_port_create(bridge_device,
brport_dev,
> +                                                 extack);
> +       if (IS_ERR(bridge_port)) {
> +               err = PTR_ERR(bridge_port);
>                 goto err_bridge_port_create;
>         }
>
> diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
b/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
> index a72e3b3b596e..e4fb573563d0 100644
> --- a/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
> +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
> @@ -93,9 +93,12 @@ static int sparx5_port_attr_set(struct net_device *dev,
const void *ctx,
>  }
>
>  static int sparx5_port_bridge_join(struct sparx5_port *port,
> -                                  struct net_device *bridge)
> +                                  struct net_device *bridge,
> +                                  struct netlink_ext_ack *extack)
>  {
>         struct sparx5 *sparx5 = port->sparx5;
> +       struct net_device *ndev = port->ndev;
> +       int err;
>
>         if (bitmap_empty(sparx5->bridge_mask, SPX5_PORTS))
>                 /* First bridged port */
> @@ -109,12 +112,20 @@ static int sparx5_port_bridge_join(struct sparx5_port
*port,
>
>         set_bit(port->portno, sparx5->bridge_mask);
>
> +       err = switchdev_bridge_port_offload(ndev, ndev, extack);
> +       if (err)
> +               goto err_switchdev_offload;
> +
>         /* Port enters in bridge mode therefor don't need to copy to
CPU
>          * frames for multicast in case the bridge is not requesting them
>          */
> -       __dev_mc_unsync(port->ndev, sparx5_mc_unsync);
> +       __dev_mc_unsync(ndev, sparx5_mc_unsync);
>
>         return 0;
> +
> +err_switchdev_offload:
> +       clear_bit(port->portno, sparx5->bridge_mask);
> +       return err;
>  }
>
>  static void sparx5_port_bridge_leave(struct sparx5_port *port,
> @@ -122,6 +133,8 @@ static void sparx5_port_bridge_leave(struct sparx5_port
*port,
>  {
>         struct sparx5 *sparx5 = port->sparx5;
>
> +       switchdev_bridge_port_unoffload(port->ndev);
> +
>         clear_bit(port->portno, sparx5->bridge_mask);
>         if (bitmap_empty(sparx5->bridge_mask, SPX5_PORTS))
>                 sparx5->hw_bridge_dev = NULL;
> @@ -139,11 +152,15 @@ static int sparx5_port_changeupper(struct net_device
*dev,
>                                    struct netdev_notifier_changeupper_info
*info)
>  {
>         struct sparx5_port *port = netdev_priv(dev);
> +       struct netlink_ext_ack *extack;
>         int err = 0;
>
> +       extack = netdev_notifier_info_to_extack(&info->info);
> +
>         if (netif_is_bridge_master(info->upper_dev)) {
>                 if (info->linking)
> -                       err = sparx5_port_bridge_join(port,
info->upper_dev);
> +                       err = sparx5_port_bridge_join(port,
info->upper_dev,
> +                                                     extack);
>                 else
>                         sparx5_port_bridge_leave(port, info->upper_dev);
>
> diff --git a/drivers/net/ethernet/mscc/ocelot_net.c
b/drivers/net/ethernet/mscc/ocelot_net.c
> index e9d260d84bf3..76b7b9536bf7 100644
> --- a/drivers/net/ethernet/mscc/ocelot_net.c
> +++ b/drivers/net/ethernet/mscc/ocelot_net.c
> @@ -1216,6 +1216,10 @@ static int ocelot_netdevice_bridge_join(struct
net_device *dev,
>
>         ocelot_port_bridge_join(ocelot, port, bridge);
>
> +       err = switchdev_bridge_port_offload(brport_dev, dev, extack);
> +       if (err)
> +               goto err_switchdev_offload;
> +
>         err = ocelot_switchdev_sync(ocelot, port, brport_dev, bridge,
extack);
>         if (err)
>                 goto err_switchdev_sync;
> @@ -1223,10 +1227,17 @@ static int ocelot_netdevice_bridge_join(struct
net_device *dev,
>         return 0;
>
>  err_switchdev_sync:
> +       switchdev_bridge_port_unoffload(brport_dev);
> +err_switchdev_offload:
>         ocelot_port_bridge_leave(ocelot, port, bridge);
>         return err;
>  }
>
> +static void ocelot_netdevice_pre_bridge_leave(struct net_device
*brport_dev)
> +{
> +       switchdev_bridge_port_unoffload(brport_dev);
> +}
> +
>  static int ocelot_netdevice_bridge_leave(struct net_device *dev,
>                                          struct net_device *brport_dev,
>                                          struct net_device *bridge)
> @@ -1279,6 +1290,18 @@ static int ocelot_netdevice_lag_join(struct
net_device *dev,
>         return err;
>  }
>
> +static void ocelot_netdevice_pre_lag_leave(struct net_device *dev,
> +                                          struct net_device *bond)
> +{
> +       struct net_device *bridge_dev;
> +
> +       bridge_dev = netdev_master_upper_dev_get(bond);
> +       if (!bridge_dev || !netif_is_bridge_master(bridge_dev))
> +               return;
> +
> +       ocelot_netdevice_pre_bridge_leave(bond);
> +}
> +
>  static int ocelot_netdevice_lag_leave(struct net_device *dev,
>                                       struct net_device *bond)
>  {
> @@ -1355,6 +1378,43 @@ ocelot_netdevice_lag_changeupper(struct net_device
*dev,
>         return NOTIFY_DONE;
>  }
>
> +static int
> +ocelot_netdevice_prechangeupper(struct net_device *dev,
> +                               struct net_device *brport_dev,
> +                               struct netdev_notifier_changeupper_info
*info)
> +{
> +       if (netif_is_bridge_master(info->upper_dev) &&
!info->linking)
> +               ocelot_netdevice_pre_bridge_leave(brport_dev);
> +
> +       if (netif_is_lag_master(info->upper_dev) &&
!info->linking)
> +               ocelot_netdevice_pre_lag_leave(dev, info->upper_dev);
> +
> +       return NOTIFY_DONE;
> +}
> +
> +static int
> +ocelot_netdevice_lag_prechangeupper(struct net_device *dev,
> +                                   struct netdev_notifier_changeupper_info
*info)
> +{
> +       struct net_device *lower;
> +       struct list_head *iter;
> +       int err = NOTIFY_DONE;
> +
> +       netdev_for_each_lower_dev(dev, lower, iter) {
> +               struct ocelot_port_private *priv = netdev_priv(lower);
> +               struct ocelot_port *ocelot_port = &priv->port;
> +
> +               if (ocelot_port->bond != dev)
> +                       return NOTIFY_OK;
> +
> +               err = ocelot_netdevice_prechangeupper(dev, lower, info);
> +               if (err)
> +                       return err;
> +       }
> +
> +       return NOTIFY_DONE;
> +}
> +
>  static int
>  ocelot_netdevice_changelowerstate(struct net_device *dev,
>                                   struct netdev_lag_lower_state_info *info)
> @@ -1382,6 +1442,17 @@ static int ocelot_netdevice_event(struct
notifier_block *unused,
>         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
>
>         switch (event) {
> +       case NETDEV_PRECHANGEUPPER: {
> +               struct netdev_notifier_changeupper_info *info = ptr;
> +
> +               if (ocelot_netdevice_dev_check(dev))
> +                       return ocelot_netdevice_prechangeupper(dev, dev,
info);
> +
> +               if (netif_is_lag_master(dev))
> +                       return ocelot_netdevice_lag_prechangeupper(dev,
info);
> +
> +               break;
> +       }
>         case NETDEV_CHANGEUPPER: {
>                 struct netdev_notifier_changeupper_info *info = ptr;
>
> diff --git a/drivers/net/ethernet/rocker/rocker.h
b/drivers/net/ethernet/rocker/rocker.h
> index 315a6e5c0f59..e75814a4654f 100644
> --- a/drivers/net/ethernet/rocker/rocker.h
> +++ b/drivers/net/ethernet/rocker/rocker.h
> @@ -119,7 +119,8 @@ struct rocker_world_ops {
>         int (*port_obj_fdb_del)(struct rocker_port *rocker_port,
>                                 u16 vid, const unsigned char *addr);
>         int (*port_master_linked)(struct rocker_port *rocker_port,
> -                                 struct net_device *master);
> +                                 struct net_device *master,
> +                                 struct netlink_ext_ack *extack);
>         int (*port_master_unlinked)(struct rocker_port *rocker_port,
>                                     struct net_device *master);
>         int (*port_neigh_update)(struct rocker_port *rocker_port,
> diff --git a/drivers/net/ethernet/rocker/rocker_main.c
b/drivers/net/ethernet/rocker/rocker_main.c
> index a46633606cae..53d407a5dbf7 100644
> --- a/drivers/net/ethernet/rocker/rocker_main.c
> +++ b/drivers/net/ethernet/rocker/rocker_main.c
> @@ -1670,13 +1670,14 @@ rocker_world_port_fdb_del(struct rocker_port
*rocker_port,
>  }
>
>  static int rocker_world_port_master_linked(struct rocker_port
*rocker_port,
> -                                          struct net_device *master)
> +                                          struct net_device *master,
> +                                          struct netlink_ext_ack *extack)
>  {
>         struct rocker_world_ops *wops = rocker_port->rocker->wops;
>
>         if (!wops->port_master_linked)
>                 return -EOPNOTSUPP;
> -       return wops->port_master_linked(rocker_port, master);
> +       return wops->port_master_linked(rocker_port, master, extack);
>  }
>
>  static int rocker_world_port_master_unlinked(struct rocker_port
*rocker_port,
> @@ -3107,6 +3108,7 @@ struct rocker_port *rocker_port_dev_lower_find(struct
net_device *dev,
>  static int rocker_netdevice_event(struct notifier_block *unused,
>                                   unsigned long event, void *ptr)
>  {
> +       struct netlink_ext_ack *extack =
netdev_notifier_info_to_extack(ptr);
>         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
>         struct netdev_notifier_changeupper_info *info;
>         struct rocker_port *rocker_port;
> @@ -3123,7 +3125,8 @@ static int rocker_netdevice_event(struct
notifier_block *unused,
>                 rocker_port = netdev_priv(dev);
>                 if (info->linking) {
>                         err = rocker_world_port_master_linked(rocker_port,
> -                                                            
info->upper_dev);
> +                                                            
info->upper_dev,
> +                                                             extack);
>                         if (err)
>                                 netdev_warn(dev, "failed to reflect
master linked (err %d)\n",
>                                             err);
> diff --git a/drivers/net/ethernet/rocker/rocker_ofdpa.c
b/drivers/net/ethernet/rocker/rocker_ofdpa.c
> index 967a634ee9ac..84dcaf8687a0 100644
> --- a/drivers/net/ethernet/rocker/rocker_ofdpa.c
> +++ b/drivers/net/ethernet/rocker/rocker_ofdpa.c
> @@ -2571,8 +2571,10 @@ static int ofdpa_port_obj_fdb_del(struct rocker_port
*rocker_port,
>  }
>
>  static int ofdpa_port_bridge_join(struct ofdpa_port *ofdpa_port,
> -                                 struct net_device *bridge)
> +                                 struct net_device *bridge,
> +                                 struct netlink_ext_ack *extack)
>  {
> +       struct net_device *dev = ofdpa_port->dev;
>         int err;
>
>         /* Port is joining bridge, so the internal VLAN for the
> @@ -2592,13 +2594,20 @@ static int ofdpa_port_bridge_join(struct ofdpa_port
*ofdpa_port,
>
>         ofdpa_port->bridge_dev = bridge;
>
> -       return ofdpa_port_vlan_add(ofdpa_port, OFDPA_UNTAGGED_VID, 0);
> +       err = ofdpa_port_vlan_add(ofdpa_port, OFDPA_UNTAGGED_VID, 0);
> +       if (err)
> +               return err;
> +
> +       return switchdev_bridge_port_offload(dev, dev, extack);
>  }
>
>  static int ofdpa_port_bridge_leave(struct ofdpa_port *ofdpa_port)
>  {
> +       struct net_device *dev = ofdpa_port->dev;
>         int err;
>
> +       switchdev_bridge_port_unoffload(dev);
> +
>         err = ofdpa_port_vlan_del(ofdpa_port, OFDPA_UNTAGGED_VID, 0);
>         if (err)
>                 return err;
> @@ -2637,13 +2646,14 @@ static int ofdpa_port_ovs_changed(struct ofdpa_port
*ofdpa_port,
>  }
>
>  static int ofdpa_port_master_linked(struct rocker_port *rocker_port,
> -                                   struct net_device *master)
> +                                   struct net_device *master,
> +                                   struct netlink_ext_ack *extack)
>  {
>         struct ofdpa_port *ofdpa_port = rocker_port->wpriv;
>         int err = 0;
>
>         if (netif_is_bridge_master(master))
> -               err = ofdpa_port_bridge_join(ofdpa_port, master);
> +               err = ofdpa_port_bridge_join(ofdpa_port, master, extack);
>         else if (netif_is_ovs_master(master))
>                 err = ofdpa_port_ovs_changed(ofdpa_port, master);
>         return err;
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index 718539cdd2f2..8b9596eb808e 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -7,6 +7,7 @@
>
>  #include <linux/clk.h>
>  #include <linux/etherdevice.h>
> +#include <linux/if_bridge.h>
>  #include <linux/if_vlan.h>
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
> @@ -2077,10 +2078,13 @@ bool am65_cpsw_port_dev_check(const struct
net_device *ndev)
>         return false;
>  }
>
> -static int am65_cpsw_netdevice_port_link(struct net_device *ndev, struct
net_device *br_ndev)
> +static int am65_cpsw_netdevice_port_link(struct net_device *ndev,
> +                                        struct net_device *br_ndev,
> +                                        struct netlink_ext_ack *extack)
>  {
>         struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
>         struct am65_cpsw_ndev_priv *priv = am65_ndev_to_priv(ndev);
> +       int err;
>
>         if (!common->br_members) {
>                 common->hw_bridge_dev = br_ndev;
> @@ -2092,6 +2096,10 @@ static int am65_cpsw_netdevice_port_link(struct
net_device *ndev, struct net_dev
>                         return -EOPNOTSUPP;
>         }
>
> +       err = switchdev_bridge_port_offload(ndev, ndev, extack);
> +       if (err)
> +               return err;
> +
>         common->br_members |= BIT(priv->port->port_id);
>
>         am65_cpsw_port_offload_fwd_mark_update(common);
> @@ -2104,6 +2112,8 @@ static void am65_cpsw_netdevice_port_unlink(struct
net_device *ndev)
>         struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
>         struct am65_cpsw_ndev_priv *priv = am65_ndev_to_priv(ndev);
>
> +       switchdev_bridge_port_unoffload(ndev);
> +
>         common->br_members &= ~BIT(priv->port->port_id);
>
>         am65_cpsw_port_offload_fwd_mark_update(common);
> @@ -2116,6 +2126,7 @@ static void am65_cpsw_netdevice_port_unlink(struct
net_device *ndev)
>  static int am65_cpsw_netdevice_event(struct notifier_block *unused,
>                                      unsigned long event, void *ptr)
>  {
> +       struct netlink_ext_ack *extack =
netdev_notifier_info_to_extack(ptr);
>         struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
>         struct netdev_notifier_changeupper_info *info;
>         int ret = NOTIFY_DONE;
> @@ -2129,7 +2140,9 @@ static int am65_cpsw_netdevice_event(struct
notifier_block *unused,
>
>                 if (netif_is_bridge_master(info->upper_dev)) {
>                         if (info->linking)
> -                               ret = am65_cpsw_netdevice_port_link(ndev,
info->upper_dev);
> +                               ret = am65_cpsw_netdevice_port_link(ndev,
> +                                                                  
info->upper_dev,
> +                                                                  
extack);
>                         else
>                                 am65_cpsw_netdevice_port_unlink(ndev);
>                 }
> diff --git a/drivers/net/ethernet/ti/cpsw_new.c
b/drivers/net/ethernet/ti/cpsw_new.c
> index 57d279fdcc9f..bf9cadfb11b5 100644
> --- a/drivers/net/ethernet/ti/cpsw_new.c
> +++ b/drivers/net/ethernet/ti/cpsw_new.c
> @@ -11,6 +11,7 @@
>  #include <linux/module.h>
>  #include <linux/irqreturn.h>
>  #include <linux/interrupt.h>
> +#include <linux/if_bridge.h>
>  #include <linux/if_ether.h>
>  #include <linux/etherdevice.h>
>  #include <linux/net_tstamp.h>
> @@ -1499,10 +1500,12 @@ static void
cpsw_port_offload_fwd_mark_update(struct cpsw_common *cpsw)
>  }
>
>  static int cpsw_netdevice_port_link(struct net_device *ndev,
> -                                   struct net_device *br_ndev)
> +                                   struct net_device *br_ndev,
> +                                   struct netlink_ext_ack *extack)
>  {
>         struct cpsw_priv *priv = netdev_priv(ndev);
>         struct cpsw_common *cpsw = priv->cpsw;
> +       int err;
>
>         if (!cpsw->br_members) {
>                 cpsw->hw_bridge_dev = br_ndev;
> @@ -1514,6 +1517,10 @@ static int cpsw_netdevice_port_link(struct
net_device *ndev,
>                         return -EOPNOTSUPP;
>         }
>
> +       err = switchdev_bridge_port_offload(ndev, ndev, extack);
> +       if (err)
> +               return err;
> +
>         cpsw->br_members |= BIT(priv->emac_port);
>
>         cpsw_port_offload_fwd_mark_update(cpsw);
> @@ -1526,6 +1533,8 @@ static void cpsw_netdevice_port_unlink(struct
net_device *ndev)
>         struct cpsw_priv *priv = netdev_priv(ndev);
>         struct cpsw_common *cpsw = priv->cpsw;
>
> +       switchdev_bridge_port_unoffload(ndev);
> +
>         cpsw->br_members &= ~BIT(priv->emac_port);
>
>         cpsw_port_offload_fwd_mark_update(cpsw);
> @@ -1538,6 +1547,7 @@ static void cpsw_netdevice_port_unlink(struct
net_device *ndev)
>  static int cpsw_netdevice_event(struct notifier_block *unused,
>                                 unsigned long event, void *ptr)
>  {
> +       struct netlink_ext_ack *extack =
netdev_notifier_info_to_extack(ptr);
>         struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
>         struct netdev_notifier_changeupper_info *info;
>         int ret = NOTIFY_DONE;
> @@ -1552,7 +1562,8 @@ static int cpsw_netdevice_event(struct notifier_block
*unused,
>                 if (netif_is_bridge_master(info->upper_dev)) {
>                         if (info->linking)
>                                 ret = cpsw_netdevice_port_link(ndev,
> -                                                             
info->upper_dev);
> +                                                             
info->upper_dev,
> +                                                              extack);
>                         else
>                                 cpsw_netdevice_port_unlink(ndev);
>                 }
> diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> index b651c5e32a28..ce413eca527e 100644
> --- a/include/linux/if_bridge.h
> +++ b/include/linux/if_bridge.h
> @@ -206,4 +206,25 @@ static inline int br_fdb_replay(const struct
net_device *br_dev,
>  }
>  #endif
>
> +#if IS_ENABLED(CONFIG_BRIDGE) && IS_ENABLED(CONFIG_NET_SWITCHDEV)
> +
> +int switchdev_bridge_port_offload(struct net_device *brport_dev,
> +                                 struct net_device *dev,
> +                                 struct netlink_ext_ack *extack);
> +void switchdev_bridge_port_unoffload(struct net_device *brport_dev);
> +
> +#else
> +
> +static inline int switchdev_bridge_port_offload(struct net_device
*brport_dev,
> +                                               struct net_device *dev,
> +                                               struct netlink_ext_ack
*extack)
> +{
> +       return -EINVAL;
> +}
> +
> +static inline void switchdev_bridge_port_unoffload(struct net_device
*brport_dev)
> +{
> +}
> +#endif
> +
>  #endif
> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
> index c0df50e4abbb..86f6d7e93ea8 100644
> --- a/net/bridge/br_if.c
> +++ b/net/bridge/br_if.c
> @@ -349,7 +349,6 @@ static void del_nbp(struct net_bridge_port *p)
>         nbp_backup_clear(p);
>
>         nbp_update_port_count(br);
> -       nbp_switchdev_del(p);
>
>         netdev_upper_dev_unlink(dev, br->dev);
>
> @@ -644,10 +643,6 @@ int br_add_if(struct net_bridge *br, struct net_device
*dev,
>         if (err)
>                 goto err5;
>
> -       err = nbp_switchdev_add(p);
> -       if (err)
> -               goto err6;
> -
>         dev_disable_lro(dev);
>
>         list_add_rcu(&p->list, &br->port_list);
> @@ -685,13 +680,13 @@ int br_add_if(struct net_bridge *br, struct
net_device *dev,
>                  */
>                 err = dev_pre_changeaddr_notify(br->dev,
dev->dev_addr, extack);
>                 if (err)
> -                       goto err7;
> +                       goto err6;
>         }
>
>         err = nbp_vlan_init(p, extack);
>         if (err) {
>                 netdev_err(dev, "failed to initialize vlan filtering
on this port\n");
> -               goto err7;
> +               goto err6;
>         }
>
>         spin_lock_bh(&br->lock);
> @@ -714,14 +709,12 @@ int br_add_if(struct net_bridge *br, struct
net_device *dev,
>
>         return 0;
>
> -err7:
> +err6:
>         if (fdb_synced)
>                 br_fdb_unsync_static(br, p);
>         list_del_rcu(&p->list);
>         br_fdb_delete_by_port(br, p, 0, 1);
>         nbp_update_port_count(br);
> -       nbp_switchdev_del(p);
> -err6:
>         netdev_upper_dev_unlink(dev, br->dev);
>  err5:
>         dev->priv_flags &= ~IFF_BRIDGE_PORT;
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 1c1732d7212a..8d2e4d807808 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -392,6 +392,8 @@ struct net_bridge_port {
>          * hardware domain.
>          */
>         int                             hwdom;
> +       int                             offload_count;
> +       struct netdev_phys_item_id      ppid;
>  #endif
>         u16                             group_fwd_mask;
>         u16                             backup_redirected_cnt;
> @@ -1856,8 +1858,6 @@ void br_switchdev_fdb_notify(struct net_bridge *br,
>  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);
> -int nbp_switchdev_add(struct net_bridge_port *p);
> -void nbp_switchdev_del(struct net_bridge_port *p);
>  void br_switchdev_init(struct net_bridge *br);
>
>  static inline void br_switchdev_frame_unmark(struct sk_buff *skb)
> @@ -1906,15 +1906,6 @@ static inline void br_switchdev_frame_unmark(struct
sk_buff *skb)
>  {
>  }
>
> -static inline int nbp_switchdev_add(struct net_bridge_port *p)
> -{
> -       return 0;
> -}
> -
> -static inline void nbp_switchdev_del(struct net_bridge_port *p)
> -{
> -}
> -
>  static inline void br_switchdev_init(struct net_bridge *br)
>  {
>  }
> diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
> index f3120f13c293..39f0787fde01 100644
> --- a/net/bridge/br_switchdev.c
> +++ b/net/bridge/br_switchdev.c
> @@ -133,7 +133,7 @@ static int nbp_switchdev_hwdom_set(struct
net_bridge_port *joining)
>
>         /* joining is yet to be added to the port list. */
>         list_for_each_entry(p, &br->port_list, list) {
> -               if (netdev_port_same_parent_id(joining->dev, p->dev))
{
> +               if (netdev_phys_item_id_same(&joining->ppid,
&p->ppid)) {
>                         joining->hwdom = p->hwdom;
>                         return 0;
>                 }
> @@ -162,27 +162,85 @@ static void nbp_switchdev_hwdom_put(struct
net_bridge_port *leaving)
>         clear_bit(leaving->hwdom, &br->busy_hwdoms);
>  }
>
> -int nbp_switchdev_add(struct net_bridge_port *p)
> +static int nbp_switchdev_add(struct net_bridge_port *p,
> +                            struct netdev_phys_item_id ppid,
> +                            struct netlink_ext_ack *extack)
>  {
> -       struct netdev_phys_item_id ppid = { };
> -       int err;
> +       if (p->offload_count) {
> +               /* Prevent unsupported configurations such as a bridge port
> +                * which is a bonding interface, and the member ports are
from
> +                * different hardware switches.
> +                */
> +               if (!netdev_phys_item_id_same(&p->ppid, &ppid))
{
> +                       NL_SET_ERR_MSG_MOD(extack,
> +                                          "Same bridge port cannot be
offloaded by two physical switches");
> +                       return -EBUSY;
> +               }
>
> -       ASSERT_RTNL();
> +               /* Tolerate drivers that call
switchdev_bridge_port_offload()
> +                * more than once for the same bridge port, such as when
the
> +                * bridge port is an offloaded bonding/team interface.
> +                */
> +               p->offload_count++;
>
> -       err = dev_get_port_parent_id(p->dev, &ppid, true);
> -       if (err) {
> -               if (err == -EOPNOTSUPP)
> -                       return 0;
> -               return err;
> +               return 0;
>         }
>
> +       p->ppid = ppid;
> +       p->offload_count = 1;
> +
>         return nbp_switchdev_hwdom_set(p);
>  }
>
> -void nbp_switchdev_del(struct net_bridge_port *p)
> +static void nbp_switchdev_del(struct net_bridge_port *p)
>  {
> -       ASSERT_RTNL();
> +       if (WARN_ON(!p->offload_count))
> +               return;
> +
> +       p->offload_count--;
> +
> +       if (p->offload_count)
> +               return;
>
>         if (p->hwdom)
>                 nbp_switchdev_hwdom_put(p);
>  }
> +
> +/* Let the bridge know that this port is offloaded, so that it can assign
a
> + * switchdev hardware domain to it.
> + */
> +int switchdev_bridge_port_offload(struct net_device *brport_dev,
> +                                 struct net_device *dev,
> +                                 struct netlink_ext_ack *extack)
> +{
> +       struct netdev_phys_item_id ppid;
> +       struct net_bridge_port *p;
> +       int err;
> +
> +       ASSERT_RTNL();
> +
> +       p = br_port_get_rtnl(brport_dev);
> +       if (!p)
> +               return -ENODEV;
> +
> +       err = dev_get_port_parent_id(dev, &ppid, false);
> +       if (err)
> +               return err;
> +
> +       return nbp_switchdev_add(p, ppid, extack);
> +}
> +EXPORT_SYMBOL_GPL(switchdev_bridge_port_offload);
> +
> +void switchdev_bridge_port_unoffload(struct net_device *brport_dev)
> +{
> +       struct net_bridge_port *p;
> +
> +       ASSERT_RTNL();
> +
> +       p = br_port_get_rtnl(brport_dev);
> +       if (!p)
> +               return;
> +
> +       nbp_switchdev_del(p);
> +}
> +EXPORT_SYMBOL_GPL(switchdev_bridge_port_unoffload);
> diff --git a/net/dsa/port.c b/net/dsa/port.c
> index 982e18771d76..7accda066149 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -292,6 +292,8 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
>                 .port = dp->index,
>                 .br = br,
>         };
> +       struct net_device *dev = dp->slave;
> +       struct net_device *brport_dev;
>         int err;
>
>         /* Here the interface is already bridged. Reflect the current
> @@ -299,16 +301,24 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
>          */
>         dp->bridge_dev = br;
>
> +       brport_dev = dsa_port_to_bridge_port(dp);
> +
>         err = dsa_broadcast(DSA_NOTIFIER_BRIDGE_JOIN, &info);
>         if (err)
>                 goto out_rollback;
>
> -       err = dsa_port_switchdev_sync(dp, extack);
> +       err = switchdev_bridge_port_offload(brport_dev, dev, extack);
>         if (err)
>                 goto out_rollback_unbridge;
>
> +       err = dsa_port_switchdev_sync(dp, extack);
> +       if (err)
> +               goto out_rollback_unoffload;
> +
>         return 0;
>
> +out_rollback_unoffload:
> +       switchdev_bridge_port_unoffload(brport_dev);
>  out_rollback_unbridge:
>         dsa_broadcast(DSA_NOTIFIER_BRIDGE_LEAVE, &info);
>  out_rollback:
> @@ -319,6 +329,10 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
>  int dsa_port_pre_bridge_leave(struct dsa_port *dp, struct net_device *br,
>                               struct netlink_ext_ack *extack)
>  {
> +       struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
> +
> +       switchdev_bridge_port_unoffload(brport_dev);
> +
>         return dsa_port_switchdev_unsync_objs(dp, br, extack);
>  }

[Please ignore if it is already reported]

Following build error noticed on Linux next 20210723 tag
with omap2plus_defconfig on arm architecture.

arm-linux-gnueabihf-ld: drivers/net/ethernet/ti/cpsw_new.o: in
function `cpsw_netdevice_event':
drivers/net/ethernet/ti/cpsw_new.c:1520: undefined reference to
`switchdev_bridge_port_offload'
arm-linux-gnueabihf-ld: drivers/net/ethernet/ti/cpsw_new.c:1537:
undefined reference to `switchdev_bridge_port_unoffload'

ref:
https://builds.tuxbuild.com/1vhy42tGxtLJWBZXR3PjnNGrzf7/
https://builds.tuxbuild.com/1vhy42tGxtLJWBZXR3PjnNGrzf7/config

Steps to reproduce:
--------------------------
# TuxMake is a command line tool and Python library that provides
# portable and repeatable Linux kernel builds across a variety of
# architectures, toolchains, kernel configurations, and make targets.
#
# TuxMake supports the concept of runtimes.
# See https://docs.tuxmake.org/runtimes/, for that to work it requires
# that you install podman or docker on your system.
#
# To install tuxmake on your system globally:
# sudo pip3 install -U tuxmake
#
# See https://docs.tuxmake.org/ for complete documentation.

tuxmake --runtime podman --target-arch arm --toolchain gcc-10
--kconfig omap2plus_defconfig

Reported-by: Linux Kernel Functional Testing <lkft at linaro.org>

--
Linaro LKFT
https://lkft.linaro.org