Merge tag 'net-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
 "Core:

   - Introduce and use a single page frag cache for allocating small skb
     heads, clawing back the 10-20% performance regression in UDP flood
     test from previous fixes.

   - Run packets which already went thru HW coalescing thru SW GRO. This
     significantly improves TCP segment coalescing and simplifies
     deployments as different workloads benefit from HW or SW GRO.

   - Shrink the size of the base zero-copy send structure.

   - Move TCP init under a new slow / sleepable version of DO_ONCE().

  BPF:

   - Add BPF-specific, any-context-safe memory allocator.

   - Add helpers/kfuncs for PKCS#7 signature verification from BPF
     programs.

   - Define a new map type and related helpers for user space -> kernel
     communication over a ring buffer (BPF_MAP_TYPE_USER_RINGBUF).

   - Allow targeting BPF iterators to loop through resources of one
     task/thread.

   - Add ability to call selected destructive functions. Expose
     crash_kexec() to allow BPF to trigger a kernel dump. Use
     CAP_SYS_BOOT check on the loading process to judge permissions.

   - Enable BPF to collect custom hierarchical cgroup stats efficiently
     by integrating with the rstat framework.

   - Support struct arguments for trampoline based programs. Only
     structs with size <= 16B and x86 are supported.

   - Invoke cgroup/connect{4,6} programs for unprivileged ICMP ping
     sockets (instead of just TCP and UDP sockets).

   - Add a helper for accessing CLOCK_TAI for time sensitive network
     related programs.

   - Support accessing network tunnel metadata's flags.

   - Make TCP SYN ACK RTO tunable by BPF programs with TCP Fast Open.

   - Add support for writing to Netfilter's nf_conn:mark.

  Protocols:

   - WiFi: more Extremely High Throughput (EHT) and Multi-Link Operation
     (MLO) work (802.11be, WiFi 7).

   - vsock: improve support for SO_RCVLOWAT.

   - SMC: support SO_REUSEPORT.

   - Netlink: define and document how to use netlink in a "modern" way.
     Support reporting missing attributes via extended ACK.

   - IPSec: support collect metadata mode for xfrm interfaces.

   - TCPv6: send consistent autoflowlabel in SYN_RECV state and RST
     packets.

   - TCP: introduce optional per-netns connection hash table to allow
     better isolation between namespaces (opt-in, at the cost of memory
     and cache pressure).

   - MPTCP: support TCP_FASTOPEN_CONNECT.

   - Add NEXT-C-SID support in Segment Routing (SRv6) End behavior.

   - Adjust IP_UNICAST_IF sockopt behavior for connected UDP sockets.

   - Open vSwitch:
      - Allow specifying ifindex of new interfaces.
      - Allow conntrack and metering in non-initial user namespace.

   - TLS: support the Korean ARIA-GCM crypto algorithm.

   - Remove DECnet support.

  Driver API:

   - Allow selecting the conduit interface used by each port in DSA
     switches, at runtime.

   - Ethernet Power Sourcing Equipment and Power Device support.

   - Add tc-taprio support for queueMaxSDU parameter, i.e. setting per
     traffic class max frame size for time-based packet schedules.

   - Support PHY rate matching - adapting between differing host-side
     and link-side speeds.

   - Introduce QUSGMII PHY mode and 1000BASE-KX interface mode.

   - Validate OF (device tree) nodes for DSA shared ports; make
     phylink-related properties mandatory on DSA and CPU ports.
     Enforcing more uniformity should allow transitioning to phylink.

   - Require that flash component name used during update matches one of
     the components for which version is reported by info_get().

   - Remove "weight" argument from driver-facing NAPI API as much as
     possible. It's one of those magic knobs which seemed like a good
     idea at the time but is too indirect to use in practice.

   - Support offload of TLS connections with 256 bit keys.

  New hardware / drivers:

   - Ethernet:
      - Microchip KSZ9896 6-port Gigabit Ethernet Switch
      - Renesas Ethernet AVB (EtherAVB-IF) Gen4 SoCs
      - Analog Devices ADIN1110 and ADIN2111 industrial single pair
        Ethernet (10BASE-T1L) MAC+PHY.
      - Rockchip RV1126 Gigabit Ethernet (a version of stmmac IP).

   - Ethernet SFPs / modules:
      - RollBall / Hilink / Turris 10G copper SFPs
      - HALNy GPON module

   - WiFi:
      - CYW43439 SDIO chipset (brcmfmac)
      - CYW89459 PCIe chipset (brcmfmac)
      - BCM4378 on Apple platforms (brcmfmac)

  Drivers:

   - CAN:
      - gs_usb: HW timestamp support

   - Ethernet PHYs:
      - lan8814: cable diagnostics

   - Ethernet NICs:
      - Intel (100G):
         - implement control of FCS/CRC stripping
         - port splitting via devlink
         - L2TPv3 filtering offload
      - nVidia/Mellanox:
         - tunnel offload for sub-functions
         - MACSec offload, w/ Extended packet number and replay window
           offload
         - significantly restructure, and optimize the AF_XDP support,
           align the behavior with other vendors
      - Huawei:
         - configuring DSCP map for traffic class selection
         - querying standard FEC statistics
         - querying SerDes lane number via ethtool
      - Marvell/Cavium:
         - egress priority flow control
         - MACSec offload
      - AMD/SolarFlare:
         - PTP over IPv6 and raw Ethernet
      - small / embedded:
         - ax88772: convert to phylink (to support SFP cages)
         - altera: tse: convert to phylink
         - ftgmac100: support fixed link
         - enetc: standard Ethtool counters
         - macb: ZynqMP SGMII dynamic configuration support
         - tsnep: support multi-queue and use page pool
         - lan743x: Rx IP & TCP checksum offload
         - igc: add xdp frags support to ndo_xdp_xmit

   - Ethernet high-speed switches:
      - Marvell (prestera):
         - support SPAN port features (traffic mirroring)
         - nexthop object offloading
      - Microchip (sparx5):
         - multicast forwarding offload
         - QoS queuing offload (tc-mqprio, tc-tbf, tc-ets)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - support RGMII cmode
      - NXP (felix):
         - standardized ethtool counters
      - Microchip (lan966x):
         - QoS queuing offload (tc-mqprio, tc-tbf, tc-cbs, tc-ets)
         - traffic policing and mirroring
         - link aggregation / bonding offload
         - QUSGMII PHY mode support

   - Qualcomm 802.11ax WiFi (ath11k):
      - cold boot calibration support on WCN6750
      - support to connect to a non-transmit MBSSID AP profile
      - enable remain-on-channel support on WCN6750
      - Wake-on-WLAN support for WCN6750
      - support to provide transmit power from firmware via nl80211
      - support to get power save duration for each client
      - spectral scan support for 160 MHz

   - MediaTek WiFi (mt76):
      - WiFi-to-Ethernet bridging offload for MT7986 chips

   - RealTek WiFi (rtw89):
      - P2P support"

* tag 'net-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1864 commits)
  eth: pse: add missing static inlines
  once: rename _SLOW to _SLEEPABLE
  net: pse-pd: add regulator based PSE driver
  dt-bindings: net: pse-dt: add bindings for regulator based PoDL PSE controller
  ethtool: add interface to interact with Ethernet Power Equipment
  net: mdiobus: search for PSE nodes by parsing PHY nodes.
  net: mdiobus: fwnode_mdiobus_register_phy() rework error handling
  net: add framework to support Ethernet PSE and PDs devices
  dt-bindings: net: phy: add PoDL PSE property
  net: marvell: prestera: Propagate nh state from hw to kernel
  net: marvell: prestera: Add neighbour cache accounting
  net: marvell: prestera: add stub handler neighbour events
  net: marvell: prestera: Add heplers to interact with fib_notifier_info
  net: marvell: prestera: Add length macros for prestera_ip_addr
  net: marvell: prestera: add delayed wq and flush wq on deinit
  net: marvell: prestera: Add strict cleanup of fib arbiter
  net: marvell: prestera: Add cleanup of allocated fib_nodes
  net: marvell: prestera: Add router nexthops ABI
  eth: octeon: fix build after netif_napi_add() changes
  net/mlx5: E-Switch, Return EBUSY if can't get mode lock
  ...

10 files changed, 1145 insertions, 236 deletions

diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index af28c24ead18..bf57ef3bce2a 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -1,7 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0
 # the core
 obj-$(CONFIG_NET_DSA) += dsa_core.o
-dsa_core-y += dsa.o dsa2.o master.o port.o slave.o switch.o tag_8021q.o
+dsa_core-y += \
+	dsa.o \
+	dsa2.o \
+	master.o \
+	netlink.o \
+	port.o \
+	slave.o \
+	switch.o \
+	tag_8021q.o
 
 # tagging formats
 obj-$(CONFIG_NET_DSA_TAG_AR9331) += tag_ar9331.o
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index be7b320cda76..64b14f655b23 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -536,8 +536,16 @@ static int __init dsa_init_module(void)
 	dsa_tag_driver_register(&DSA_TAG_DRIVER_NAME(none_ops),
 				THIS_MODULE);
 
+	rc = rtnl_link_register(&dsa_link_ops);
+	if (rc)
+		goto netlink_register_fail;
+
 	return 0;
 
+netlink_register_fail:
+	dsa_tag_driver_unregister(&DSA_TAG_DRIVER_NAME(none_ops));
+	dsa_slave_unregister_notifier();
+	dev_remove_pack(&dsa_pack_type);
 register_notifier_fail:
 	destroy_workqueue(dsa_owq);
 
@@ -547,6 +555,7 @@ module_init(dsa_init_module);
 
 static void __exit dsa_cleanup_module(void)
 {
+	rtnl_link_unregister(&dsa_link_ops);
 	dsa_tag_driver_unregister(&DSA_TAG_DRIVER_NAME(none_ops));
 
 	dsa_slave_unregister_notifier();
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index cac48a741f27..af0e2c0394ac 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -387,6 +387,20 @@ static struct dsa_port *dsa_tree_find_first_cpu(struct dsa_switch_tree *dst)
 	return NULL;
 }
 
+struct net_device *dsa_tree_find_first_master(struct dsa_switch_tree *dst)
+{
+	struct device_node *ethernet;
+	struct net_device *master;
+	struct dsa_port *cpu_dp;
+
+	cpu_dp = dsa_tree_find_first_cpu(dst);
+	ethernet = of_parse_phandle(cpu_dp->dn, "ethernet", 0);
+	master = of_find_net_device_by_node(ethernet);
+	of_node_put(ethernet);
+
+	return master;
+}
+
 /* Assign the default CPU port (the first one in the tree) to all ports of the
  * fabric which don't already have one as part of their own switch.
  */
@@ -447,6 +461,72 @@ static void dsa_tree_teardown_cpu_ports(struct dsa_switch_tree *dst)
 			dp->cpu_dp = NULL;
 }
 
+static int dsa_port_devlink_setup(struct dsa_port *dp)
+{
+	struct devlink_port *dlp = &dp->devlink_port;
+	struct dsa_switch_tree *dst = dp->ds->dst;
+	struct devlink_port_attrs attrs = {};
+	struct devlink *dl = dp->ds->devlink;
+	struct dsa_switch *ds = dp->ds;
+	const unsigned char *id;
+	unsigned char len;
+	int err;
+
+	memset(dlp, 0, sizeof(*dlp));
+	devlink_port_init(dl, dlp);
+
+	if (ds->ops->port_setup) {
+		err = ds->ops->port_setup(ds, dp->index);
+		if (err)
+			return err;
+	}
+
+	id = (const unsigned char *)&dst->index;
+	len = sizeof(dst->index);
+
+	attrs.phys.port_number = dp->index;
+	memcpy(attrs.switch_id.id, id, len);
+	attrs.switch_id.id_len = len;
+
+	switch (dp->type) {
+	case DSA_PORT_TYPE_UNUSED:
+		attrs.flavour = DEVLINK_PORT_FLAVOUR_UNUSED;
+		break;
+	case DSA_PORT_TYPE_CPU:
+		attrs.flavour = DEVLINK_PORT_FLAVOUR_CPU;
+		break;
+	case DSA_PORT_TYPE_DSA:
+		attrs.flavour = DEVLINK_PORT_FLAVOUR_DSA;
+		break;
+	case DSA_PORT_TYPE_USER:
+		attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
+		break;
+	}
+
+	devlink_port_attrs_set(dlp, &attrs);
+	err = devlink_port_register(dl, dlp, dp->index);
+	if (err) {
+		if (ds->ops->port_teardown)
+			ds->ops->port_teardown(ds, dp->index);
+		return err;
+	}
+
+	return 0;
+}
+
+static void dsa_port_devlink_teardown(struct dsa_port *dp)
+{
+	struct devlink_port *dlp = &dp->devlink_port;
+	struct dsa_switch *ds = dp->ds;
+
+	devlink_port_unregister(dlp);
+
+	if (ds->ops->port_teardown)
+		ds->ops->port_teardown(ds, dp->index);
+
+	devlink_port_fini(dlp);
+}
+
 static int dsa_port_setup(struct dsa_port *dp)
 {
 	struct devlink_port *dlp = &dp->devlink_port;
@@ -458,21 +538,25 @@ static int dsa_port_setup(struct dsa_port *dp)
 	if (dp->setup)
 		return 0;
 
-	if (ds->ops->port_setup) {
-		err = ds->ops->port_setup(ds, dp->index);
-		if (err)
-			return err;
-	}
+	err = dsa_port_devlink_setup(dp);
+	if (err)
+		return err;
 
 	switch (dp->type) {
 	case DSA_PORT_TYPE_UNUSED:
 		dsa_port_disable(dp);
 		break;
 	case DSA_PORT_TYPE_CPU:
-		err = dsa_port_link_register_of(dp);
-		if (err)
-			break;
-		dsa_port_link_registered = true;
+		if (dp->dn) {
+			err = dsa_shared_port_link_register_of(dp);
+			if (err)
+				break;
+			dsa_port_link_registered = true;
+		} else {
+			dev_warn(ds->dev,
+				 "skipping link registration for CPU port %d\n",
+				 dp->index);
+		}
 
 		err = dsa_port_enable(dp, NULL);
 		if (err)
@@ -481,10 +565,16 @@ static int dsa_port_setup(struct dsa_port *dp)
 
 		break;
 	case DSA_PORT_TYPE_DSA:
-		err = dsa_port_link_register_of(dp);
-		if (err)
-			break;
-		dsa_port_link_registered = true;
+		if (dp->dn) {
+			err = dsa_shared_port_link_register_of(dp);
+			if (err)
+				break;
+			dsa_port_link_registered = true;
+		} else {
+			dev_warn(ds->dev,
+				 "skipping link registration for DSA port %d\n",
+				 dp->index);
+		}
 
 		err = dsa_port_enable(dp, NULL);
 		if (err)
@@ -505,10 +595,9 @@ static int dsa_port_setup(struct dsa_port *dp)
 	if (err && dsa_port_enabled)
 		dsa_port_disable(dp);
 	if (err && dsa_port_link_registered)
-		dsa_port_link_unregister_of(dp);
+		dsa_shared_port_link_unregister_of(dp);
 	if (err) {
-		if (ds->ops->port_teardown)
-			ds->ops->port_teardown(ds, dp->index);
+		dsa_port_devlink_teardown(dp);
 		return err;
 	}
 
@@ -517,59 +606,13 @@ static int dsa_port_setup(struct dsa_port *dp)
 	return 0;
 }
 
-static int dsa_port_devlink_setup(struct dsa_port *dp)
-{
-	struct devlink_port *dlp = &dp->devlink_port;
-	struct dsa_switch_tree *dst = dp->ds->dst;
-	struct devlink_port_attrs attrs = {};
-	struct devlink *dl = dp->ds->devlink;
-	const unsigned char *id;
-	unsigned char len;
-	int err;
-
-	id = (const unsigned char *)&dst->index;
-	len = sizeof(dst->index);
-
-	attrs.phys.port_number = dp->index;
-	memcpy(attrs.switch_id.id, id, len);
-	attrs.switch_id.id_len = len;
-	memset(dlp, 0, sizeof(*dlp));
-
-	switch (dp->type) {
-	case DSA_PORT_TYPE_UNUSED:
-		attrs.flavour = DEVLINK_PORT_FLAVOUR_UNUSED;
-		break;
-	case DSA_PORT_TYPE_CPU:
-		attrs.flavour = DEVLINK_PORT_FLAVOUR_CPU;
-		break;
-	case DSA_PORT_TYPE_DSA:
-		attrs.flavour = DEVLINK_PORT_FLAVOUR_DSA;
-		break;
-	case DSA_PORT_TYPE_USER:
-		attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
-		break;
-	}
-
-	devlink_port_attrs_set(dlp, &attrs);
-	err = devlink_port_register(dl, dlp, dp->index);
-
-	if (!err)
-		dp->devlink_port_setup = true;
-
-	return err;
-}
-
 static void dsa_port_teardown(struct dsa_port *dp)
 {
 	struct devlink_port *dlp = &dp->devlink_port;
-	struct dsa_switch *ds = dp->ds;
 
 	if (!dp->setup)
 		return;
 
-	if (ds->ops->port_teardown)
-		ds->ops->port_teardown(ds, dp->index);
-
 	devlink_port_type_clear(dlp);
 
 	switch (dp->type) {
@@ -577,11 +620,13 @@ static void dsa_port_teardown(struct dsa_port *dp)
 		break;
 	case DSA_PORT_TYPE_CPU:
 		dsa_port_disable(dp);
-		dsa_port_link_unregister_of(dp);
+		if (dp->dn)
+			dsa_shared_port_link_unregister_of(dp);
 		break;
 	case DSA_PORT_TYPE_DSA:
 		dsa_port_disable(dp);
-		dsa_port_link_unregister_of(dp);
+		if (dp->dn)
+			dsa_shared_port_link_unregister_of(dp);
 		break;
 	case DSA_PORT_TYPE_USER:
 		if (dp->slave) {
@@ -591,46 +636,15 @@ static void dsa_port_teardown(struct dsa_port *dp)
 		break;
 	}
 
-	dp->setup = false;
-}
-
-static void dsa_port_devlink_teardown(struct dsa_port *dp)
-{
-	struct devlink_port *dlp = &dp->devlink_port;
+	dsa_port_devlink_teardown(dp);
 
-	if (dp->devlink_port_setup)
-		devlink_port_unregister(dlp);
-	dp->devlink_port_setup = false;
+	dp->setup = false;
 }
 
-/* Destroy the current devlink port, and create a new one which has the UNUSED
- * flavour. At this point, any call to ds->ops->port_setup has been already
- * balanced out by a call to ds->ops->port_teardown, so we know that any
- * devlink port regions the driver had are now unregistered. We then call its
- * ds->ops->port_setup again, in order for the driver to re-create them on the
- * new devlink port.
- */
-static int dsa_port_reinit_as_unused(struct dsa_port *dp)
+static int dsa_port_setup_as_unused(struct dsa_port *dp)
 {
-	struct dsa_switch *ds = dp->ds;
-	int err;
-
-	dsa_port_devlink_teardown(dp);
 	dp->type = DSA_PORT_TYPE_UNUSED;
-	err = dsa_port_devlink_setup(dp);
-	if (err)
-		return err;
-
-	if (ds->ops->port_setup) {
-		/* On error, leave the devlink port registered,
-		 * dsa_switch_teardown will clean it up later.
-		 */
-		err = ds->ops->port_setup(ds, dp->index);
-		if (err)
-			return err;
-	}
-
-	return 0;
+	return dsa_port_setup(dp);
 }
 
 static int dsa_devlink_info_get(struct devlink *dl,
@@ -854,7 +868,6 @@ static int dsa_switch_setup(struct dsa_switch *ds)
 {
 	struct dsa_devlink_priv *dl_priv;
 	struct device_node *dn;
-	struct dsa_port *dp;
 	int err;
 
 	if (ds->setup)
@@ -877,18 +890,9 @@ static int dsa_switch_setup(struct dsa_switch *ds)
 	dl_priv = devlink_priv(ds->devlink);
 	dl_priv->ds = ds;
 
-	/* Setup devlink port instances now, so that the switch
-	 * setup() can register regions etc, against the ports
-	 */
-	dsa_switch_for_each_port(dp, ds) {
-		err = dsa_port_devlink_setup(dp);
-		if (err)
-			goto unregister_devlink_ports;
-	}
-
 	err = dsa_switch_register_notifier(ds);
 	if (err)
-		goto unregister_devlink_ports;
+		goto devlink_free;
 
 	ds->configure_vlan_while_not_filtering = true;
 
@@ -929,9 +933,7 @@ teardown:
 		ds->ops->teardown(ds);
 unregister_notifier:
 	dsa_switch_unregister_notifier(ds);
-unregister_devlink_ports:
-	dsa_switch_for_each_port(dp, ds)
-		dsa_port_devlink_teardown(dp);
+devlink_free:
 	devlink_free(ds->devlink);
 	ds->devlink = NULL;
 	return err;
@@ -939,8 +941,6 @@ unregister_devlink_ports:
 
 static void dsa_switch_teardown(struct dsa_switch *ds)
 {
-	struct dsa_port *dp;
-
 	if (!ds->setup)
 		return;
 
@@ -959,8 +959,6 @@ static void dsa_switch_teardown(struct dsa_switch *ds)
 	dsa_switch_unregister_notifier(ds);
 
 	if (ds->devlink) {
-		dsa_switch_for_each_port(dp, ds)
-			dsa_port_devlink_teardown(dp);
 		devlink_free(ds->devlink);
 		ds->devlink = NULL;
 	}
@@ -1013,7 +1011,7 @@ static int dsa_tree_setup_ports(struct dsa_switch_tree *dst)
 		if (dsa_port_is_user(dp) || dsa_port_is_unused(dp)) {
 			err = dsa_port_setup(dp);
 			if (err) {
-				err = dsa_port_reinit_as_unused(dp);
+				err = dsa_port_setup_as_unused(dp);
 				if (err)
 					goto teardown;
 			}
@@ -1046,26 +1044,24 @@ static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 
 static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
 {
-	struct dsa_port *dp;
+	struct dsa_port *cpu_dp;
 	int err = 0;
 
 	rtnl_lock();
 
-	list_for_each_entry(dp, &dst->ports, list) {
-		if (dsa_port_is_cpu(dp)) {
-			struct net_device *master = dp->master;
-			bool admin_up = (master->flags & IFF_UP) &&
-					!qdisc_tx_is_noop(master);
+	dsa_tree_for_each_cpu_port(cpu_dp, dst) {
+		struct net_device *master = cpu_dp->master;
+		bool admin_up = (master->flags & IFF_UP) &&
+				!qdisc_tx_is_noop(master);
 
-			err = dsa_master_setup(master, dp);
-			if (err)
-				break;
+		err = dsa_master_setup(master, cpu_dp);
+		if (err)
+			break;
 
-			/* Replay master state event */
-			dsa_tree_master_admin_state_change(dst, master, admin_up);
-			dsa_tree_master_oper_state_change(dst, master,
-							  netif_oper_up(master));
-		}
+		/* Replay master state event */
+		dsa_tree_master_admin_state_change(dst, master, admin_up);
+		dsa_tree_master_oper_state_change(dst, master,
+						  netif_oper_up(master));
 	}
 
 	rtnl_unlock();
@@ -1075,22 +1071,20 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
 
 static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
 {
-	struct dsa_port *dp;
+	struct dsa_port *cpu_dp;
 
 	rtnl_lock();
 
-	list_for_each_entry(dp, &dst->ports, list) {
-		if (dsa_port_is_cpu(dp)) {
-			struct net_device *master = dp->master;
+	dsa_tree_for_each_cpu_port(cpu_dp, dst) {
+		struct net_device *master = cpu_dp->master;
 
-			/* Synthesizing an "admin down" state is sufficient for
-			 * the switches to get a notification if the master is
-			 * currently up and running.
-			 */
-			dsa_tree_master_admin_state_change(dst, master, false);
+		/* Synthesizing an "admin down" state is sufficient for
+		 * the switches to get a notification if the master is
+		 * currently up and running.
+		 */
+		dsa_tree_master_admin_state_change(dst, master, false);
 
-			dsa_master_teardown(master);
-		}
+		dsa_master_teardown(master);
 	}
 
 	rtnl_unlock();
@@ -1238,7 +1232,6 @@ out_disconnect:
  * they would have formed disjoint trees (different "dsa,member" values).
  */
 int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
-			      struct net_device *master,
 			      const struct dsa_device_ops *tag_ops,
 			      const struct dsa_device_ops *old_tag_ops)
 {
@@ -1254,12 +1247,9 @@ int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
 	 * attempts to change the tagging protocol. If we ever lift the IFF_UP
 	 * restriction, there needs to be another mutex which serializes this.
 	 */
-	if (master->flags & IFF_UP)
-		goto out_unlock;
-
-	list_for_each_entry(dp, &dst->ports, list) {
-		if (!dsa_port_is_user(dp))
-			continue;
+	dsa_tree_for_each_user_port(dp, dst) {
+		if (dsa_port_to_master(dp)->flags & IFF_UP)
+			goto out_unlock;
 
 		if (dp->slave->flags & IFF_UP)
 			goto out_unlock;
@@ -1306,6 +1296,12 @@ void dsa_tree_master_admin_state_change(struct dsa_switch_tree *dst,
 	struct dsa_port *cpu_dp = master->dsa_ptr;
 	bool notify = false;
 
+	/* Don't keep track of admin state on LAG DSA masters,
+	 * but rather just of physical DSA masters
+	 */
+	if (netif_is_lag_master(master))
+		return;
+
 	if ((dsa_port_master_is_operational(cpu_dp)) !=
 	    (up && cpu_dp->master_oper_up))
 		notify = true;
@@ -1323,6 +1319,12 @@ void dsa_tree_master_oper_state_change(struct dsa_switch_tree *dst,
 	struct dsa_port *cpu_dp = master->dsa_ptr;
 	bool notify = false;
 
+	/* Don't keep track of oper state on LAG DSA masters,
+	 * but rather just of physical DSA masters
+	 */
+	if (netif_is_lag_master(master))
+		return;
+
 	if ((dsa_port_master_is_operational(cpu_dp)) !=
 	    (cpu_dp->master_admin_up && up))
 		notify = true;
@@ -1791,7 +1793,7 @@ void dsa_switch_shutdown(struct dsa_switch *ds)
 	rtnl_lock();
 
 	dsa_switch_for_each_user_port(dp, ds) {
-		master = dp->cpu_dp->master;
+		master = dsa_port_to_master(dp);
 		slave_dev = dp->slave;
 
 		netdev_upper_dev_unlink(master, slave_dev);
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index d9722e49864b..6e65c7ffd6f3 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -88,6 +88,7 @@ struct dsa_notifier_lag_info {
 	const struct dsa_port *dp;
 	struct dsa_lag lag;
 	struct netdev_lag_upper_info *info;
+	struct netlink_ext_ack *extack;
 };
 
 /* DSA_NOTIFIER_VLAN_* */
@@ -184,6 +185,11 @@ static inline int dsa_tag_protocol_overhead(const struct dsa_device_ops *ops)
 /* master.c */
 int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp);
 void dsa_master_teardown(struct net_device *dev);
+int dsa_master_lag_setup(struct net_device *lag_dev, struct dsa_port *cpu_dp,
+			 struct netdev_lag_upper_info *uinfo,
+			 struct netlink_ext_ack *extack);
+void dsa_master_lag_teardown(struct net_device *lag_dev,
+			     struct dsa_port *cpu_dp);
 
 static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
 						       int device, int port)
@@ -200,6 +206,9 @@ static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
 	return NULL;
 }
 
+/* netlink.c */
+extern struct rtnl_link_ops dsa_link_ops __read_mostly;
+
 /* port.c */
 void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
 			       const struct dsa_device_ops *tag_ops);
@@ -285,13 +294,16 @@ int dsa_port_mrp_add_ring_role(const struct dsa_port *dp,
 int dsa_port_mrp_del_ring_role(const struct dsa_port *dp,
 			       const struct switchdev_obj_ring_role_mrp *mrp);
 int dsa_port_phylink_create(struct dsa_port *dp);
-int dsa_port_link_register_of(struct dsa_port *dp);
-void dsa_port_link_unregister_of(struct dsa_port *dp);
+void dsa_port_phylink_destroy(struct dsa_port *dp);
+int dsa_shared_port_link_register_of(struct dsa_port *dp);
+void dsa_shared_port_link_unregister_of(struct dsa_port *dp);
 int dsa_port_hsr_join(struct dsa_port *dp, struct net_device *hsr);
 void dsa_port_hsr_leave(struct dsa_port *dp, struct net_device *hsr);
 int dsa_port_tag_8021q_vlan_add(struct dsa_port *dp, u16 vid, bool broadcast);
 void dsa_port_tag_8021q_vlan_del(struct dsa_port *dp, u16 vid, bool broadcast);
 void dsa_port_set_host_flood(struct dsa_port *dp, bool uc, bool mc);
+int dsa_port_change_master(struct dsa_port *dp, struct net_device *master,
+			   struct netlink_ext_ack *extack);
 
 /* slave.c */
 extern const struct dsa_device_ops notag_netdev_ops;
@@ -305,8 +317,12 @@ int dsa_slave_suspend(struct net_device *slave_dev);
 int dsa_slave_resume(struct net_device *slave_dev);
 int dsa_slave_register_notifier(void);
 void dsa_slave_unregister_notifier(void);
+void dsa_slave_sync_ha(struct net_device *dev);
+void dsa_slave_unsync_ha(struct net_device *dev);
 void dsa_slave_setup_tagger(struct net_device *slave);
 int dsa_slave_change_mtu(struct net_device *dev, int new_mtu);
+int dsa_slave_change_master(struct net_device *dev, struct net_device *master,
+			    struct netlink_ext_ack *extack);
 int dsa_slave_manage_vlan_filtering(struct net_device *dev,
 				    bool vlan_filtering);
 
@@ -322,7 +338,7 @@ dsa_slave_to_master(const struct net_device *dev)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 
-	return dp->cpu_dp->master;
+	return dsa_port_to_master(dp);
 }
 
 /* If under a bridge with vlan_filtering=0, make sure to send pvid-tagged
@@ -542,10 +558,10 @@ void dsa_lag_map(struct dsa_switch_tree *dst, struct dsa_lag *lag);
 void dsa_lag_unmap(struct dsa_switch_tree *dst, struct dsa_lag *lag);
 struct dsa_lag *dsa_tree_lag_find(struct dsa_switch_tree *dst,
 				  const struct net_device *lag_dev);
+struct net_device *dsa_tree_find_first_master(struct dsa_switch_tree *dst);
 int dsa_tree_notify(struct dsa_switch_tree *dst, unsigned long e, void *v);
 int dsa_broadcast(unsigned long e, void *v);
 int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
-			      struct net_device *master,
 			      const struct dsa_device_ops *tag_ops,
 			      const struct dsa_device_ops *old_tag_ops);
 void dsa_tree_master_admin_state_change(struct dsa_switch_tree *dst,
diff --git a/net/dsa/master.c b/net/dsa/master.c
index 2851e44c4cf0..40367ab41cf8 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -58,7 +58,7 @@ static void dsa_master_get_regs(struct net_device *dev,
 	}
 
 	cpu_info = (struct ethtool_drvinfo *)data;
-	strlcpy(cpu_info->driver, "dsa", sizeof(cpu_info->driver));
+	strscpy(cpu_info->driver, "dsa", sizeof(cpu_info->driver));
 	data += sizeof(*cpu_info);
 	cpu_regs = (struct ethtool_regs *)data;
 	data += sizeof(*cpu_regs);
@@ -226,6 +226,9 @@ static int dsa_master_ethtool_setup(struct net_device *dev)
 	struct dsa_switch *ds = cpu_dp->ds;
 	struct ethtool_ops *ops;
 
+	if (netif_is_lag_master(dev))
+		return 0;
+
 	ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
 	if (!ops)
 		return -ENOMEM;
@@ -250,6 +253,9 @@ static void dsa_master_ethtool_teardown(struct net_device *dev)
 {
 	struct dsa_port *cpu_dp = dev->dsa_ptr;
 
+	if (netif_is_lag_master(dev))
+		return;
+
 	dev->ethtool_ops = cpu_dp->orig_ethtool_ops;
 	cpu_dp->orig_ethtool_ops = NULL;
 }
@@ -257,6 +263,9 @@ static void dsa_master_ethtool_teardown(struct net_device *dev)
 static void dsa_netdev_ops_set(struct net_device *dev,
 			       const struct dsa_netdevice_ops *ops)
 {
+	if (netif_is_lag_master(dev))
+		return;
+
 	dev->dsa_ptr->netdev_ops = ops;
 }
 
@@ -307,7 +316,7 @@ static ssize_t tagging_store(struct device *d, struct device_attribute *attr,
 		 */
 		goto out;
 
-	err = dsa_tree_change_tag_proto(cpu_dp->ds->dst, dev, new_tag_ops,
+	err = dsa_tree_change_tag_proto(cpu_dp->ds->dst, new_tag_ops,
 					old_tag_ops);
 	if (err) {
 		/* On failure the old tagger is restored, so we don't need the
@@ -355,12 +364,14 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 	mtu = ETH_DATA_LEN + dsa_tag_protocol_overhead(tag_ops);
 
 	/* The DSA master must use SET_NETDEV_DEV for this to work. */
-	consumer_link = device_link_add(ds->dev, dev->dev.parent,
-					DL_FLAG_AUTOREMOVE_CONSUMER);
-	if (!consumer_link)
-		netdev_err(dev,
-			   "Failed to create a device link to DSA switch %s\n",
-			   dev_name(ds->dev));
+	if (!netif_is_lag_master(dev)) {
+		consumer_link = device_link_add(ds->dev, dev->dev.parent,
+						DL_FLAG_AUTOREMOVE_CONSUMER);
+		if (!consumer_link)
+			netdev_err(dev,
+				   "Failed to create a device link to DSA switch %s\n",
+				   dev_name(ds->dev));
+	}
 
 	/* The switch driver may not implement ->port_change_mtu(), case in
 	 * which dsa_slave_change_mtu() will not update the master MTU either,
@@ -417,3 +428,52 @@ void dsa_master_teardown(struct net_device *dev)
 	 */
 	wmb();
 }
+
+int dsa_master_lag_setup(struct net_device *lag_dev, struct dsa_port *cpu_dp,
+			 struct netdev_lag_upper_info *uinfo,
+			 struct netlink_ext_ack *extack)
+{
+	bool master_setup = false;
+	int err;
+
+	if (!netdev_uses_dsa(lag_dev)) {
+		err = dsa_master_setup(lag_dev, cpu_dp);
+		if (err)
+			return err;
+
+		master_setup = true;
+	}
+
+	err = dsa_port_lag_join(cpu_dp, lag_dev, uinfo, extack);
+	if (err) {
+		if (extack && !extack->_msg)
+			NL_SET_ERR_MSG_MOD(extack,
+					   "CPU port failed to join LAG");
+		goto out_master_teardown;
+	}
+
+	return 0;
+
+out_master_teardown:
+	if (master_setup)
+		dsa_master_teardown(lag_dev);
+	return err;
+}
+
+/* Tear down a master if there isn't any other user port on it,
+ * optionally also destroying LAG information.
+ */
+void dsa_master_lag_teardown(struct net_device *lag_dev,
+			     struct dsa_port *cpu_dp)
+{
+	struct net_device *upper;
+	struct list_head *iter;
+
+	dsa_port_lag_leave(cpu_dp, lag_dev);
+
+	netdev_for_each_upper_dev_rcu(lag_dev, upper, iter)
+		if (dsa_slave_dev_check(upper))
+			return;
+
+	dsa_master_teardown(lag_dev);
+}
diff --git a/net/dsa/netlink.c b/net/dsa/netlink.c
new file mode 100644
index 000000000000..ecf9ed1de185
--- /dev/null
+++ b/net/dsa/netlink.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2022 NXP
+ */
+#include <linux/netdevice.h>
+#include <net/rtnetlink.h>
+
+#include "dsa_priv.h"
+
+static const struct nla_policy dsa_policy[IFLA_DSA_MAX + 1] = {
+	[IFLA_DSA_MASTER]	= { .type = NLA_U32 },
+};
+
+static int dsa_changelink(struct net_device *dev, struct nlattr *tb[],
+			  struct nlattr *data[],
+			  struct netlink_ext_ack *extack)
+{
+	int err;
+
+	if (!data)
+		return 0;
+
+	if (data[IFLA_DSA_MASTER]) {
+		u32 ifindex = nla_get_u32(data[IFLA_DSA_MASTER]);
+		struct net_device *master;
+
+		master = __dev_get_by_index(dev_net(dev), ifindex);
+		if (!master)
+			return -EINVAL;
+
+		err = dsa_slave_change_master(dev, master, extack);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static size_t dsa_get_size(const struct net_device *dev)
+{
+	return nla_total_size(sizeof(u32)) +	/* IFLA_DSA_MASTER  */
+	       0;
+}
+
+static int dsa_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	struct net_device *master = dsa_slave_to_master(dev);
+
+	if (nla_put_u32(skb, IFLA_DSA_MASTER, master->ifindex))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+struct rtnl_link_ops dsa_link_ops __read_mostly = {
+	.kind			= "dsa",
+	.priv_size		= sizeof(struct dsa_port),
+	.maxtype		= IFLA_DSA_MAX,
+	.policy			= dsa_policy,
+	.changelink		= dsa_changelink,
+	.get_size		= dsa_get_size,
+	.fill_info		= dsa_fill_info,
+	.netns_refund		= true,
+};
diff --git a/net/dsa/port.c b/net/dsa/port.c
index a8895ee3cd60..e4a0513816bb 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/if_bridge.h>
+#include <linux/netdevice.h>
 #include <linux/notifier.h>
 #include <linux/of_mdio.h>
 #include <linux/of_net.h>
@@ -634,6 +635,7 @@ int dsa_port_lag_join(struct dsa_port *dp, struct net_device *lag_dev,
 	struct dsa_notifier_lag_info info = {
 		.dp = dp,
 		.info = uinfo,
+		.extack = extack,
 	};
 	struct net_device *bridge_dev;
 	int err;
@@ -1026,7 +1028,7 @@ int dsa_port_standalone_host_fdb_add(struct dsa_port *dp,
 int dsa_port_bridge_host_fdb_add(struct dsa_port *dp,
 				 const unsigned char *addr, u16 vid)
 {
-	struct dsa_port *cpu_dp = dp->cpu_dp;
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_db db = {
 		.type = DSA_DB_BRIDGE,
 		.bridge = *dp->bridge,
@@ -1037,8 +1039,8 @@ int dsa_port_bridge_host_fdb_add(struct dsa_port *dp,
 	 * requires rtnl_lock(), since we can't guarantee that is held here,
 	 * and we can't take it either.
 	 */
-	if (cpu_dp->master->priv_flags & IFF_UNICAST_FLT) {
-		err = dev_uc_add(cpu_dp->master, addr);
+	if (master->priv_flags & IFF_UNICAST_FLT) {
+		err = dev_uc_add(master, addr);
 		if (err)
 			return err;
 	}
@@ -1077,15 +1079,15 @@ int dsa_port_standalone_host_fdb_del(struct dsa_port *dp,
 int dsa_port_bridge_host_fdb_del(struct dsa_port *dp,
 				 const unsigned char *addr, u16 vid)
 {
-	struct dsa_port *cpu_dp = dp->cpu_dp;
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_db db = {
 		.type = DSA_DB_BRIDGE,
 		.bridge = *dp->bridge,
 	};
 	int err;
 
-	if (cpu_dp->master->priv_flags & IFF_UNICAST_FLT) {
-		err = dev_uc_del(cpu_dp->master, addr);
+	if (master->priv_flags & IFF_UNICAST_FLT) {
+		err = dev_uc_del(master, addr);
 		if (err)
 			return err;
 	}
@@ -1208,14 +1210,14 @@ int dsa_port_standalone_host_mdb_add(const struct dsa_port *dp,
 int dsa_port_bridge_host_mdb_add(const struct dsa_port *dp,
 				 const struct switchdev_obj_port_mdb *mdb)
 {
-	struct dsa_port *cpu_dp = dp->cpu_dp;
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_db db = {
 		.type = DSA_DB_BRIDGE,
 		.bridge = *dp->bridge,
 	};
 	int err;
 
-	err = dev_mc_add(cpu_dp->master, mdb->addr);
+	err = dev_mc_add(master, mdb->addr);
 	if (err)
 		return err;
 
@@ -1252,14 +1254,14 @@ int dsa_port_standalone_host_mdb_del(const struct dsa_port *dp,
 int dsa_port_bridge_host_mdb_del(const struct dsa_port *dp,
 				 const struct switchdev_obj_port_mdb *mdb)
 {
-	struct dsa_port *cpu_dp = dp->cpu_dp;
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_db db = {
 		.type = DSA_DB_BRIDGE,
 		.bridge = *dp->bridge,
 	};
 	int err;
 
-	err = dev_mc_del(cpu_dp->master, mdb->addr);
+	err = dev_mc_del(master, mdb->addr);
 	if (err)
 		return err;
 
@@ -1294,19 +1296,19 @@ int dsa_port_host_vlan_add(struct dsa_port *dp,
 			   const struct switchdev_obj_port_vlan *vlan,
 			   struct netlink_ext_ack *extack)
 {
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_notifier_vlan_info info = {
 		.dp = dp,
 		.vlan = vlan,
 		.extack = extack,
 	};
-	struct dsa_port *cpu_dp = dp->cpu_dp;
 	int err;
 
 	err = dsa_port_notify(dp, DSA_NOTIFIER_HOST_VLAN_ADD, &info);
 	if (err && err != -EOPNOTSUPP)
 		return err;
 
-	vlan_vid_add(cpu_dp->master, htons(ETH_P_8021Q), vlan->vid);
+	vlan_vid_add(master, htons(ETH_P_8021Q), vlan->vid);
 
 	return err;
 }
@@ -1314,18 +1316,18 @@ int dsa_port_host_vlan_add(struct dsa_port *dp,
 int dsa_port_host_vlan_del(struct dsa_port *dp,
 			   const struct switchdev_obj_port_vlan *vlan)
 {
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_notifier_vlan_info info = {
 		.dp = dp,
 		.vlan = vlan,
 	};
-	struct dsa_port *cpu_dp = dp->cpu_dp;
 	int err;
 
 	err = dsa_port_notify(dp, DSA_NOTIFIER_HOST_VLAN_DEL, &info);
 	if (err && err != -EOPNOTSUPP)
 		return err;
 
-	vlan_vid_del(cpu_dp->master, htons(ETH_P_8021Q), vlan->vid);
+	vlan_vid_del(master, htons(ETH_P_8021Q), vlan->vid);
 
 	return err;
 }
@@ -1374,6 +1376,136 @@ int dsa_port_mrp_del_ring_role(const struct dsa_port *dp,
 	return ds->ops->port_mrp_del_ring_role(ds, dp->index, mrp);
 }
 
+static int dsa_port_assign_master(struct dsa_port *dp,
+				  struct net_device *master,
+				  struct netlink_ext_ack *extack,
+				  bool fail_on_err)
+{
+	struct dsa_switch *ds = dp->ds;
+	int port = dp->index, err;
+
+	err = ds->ops->port_change_master(ds, port, master, extack);
+	if (err && !fail_on_err)
+		dev_err(ds->dev, "port %d failed to assign master %s: %pe\n",
+			port, master->name, ERR_PTR(err));
+
+	if (err && fail_on_err)
+		return err;
+
+	dp->cpu_dp = master->dsa_ptr;
+	dp->cpu_port_in_lag = netif_is_lag_master(master);
+
+	return 0;
+}
+
+/* Change the dp->cpu_dp affinity for a user port. Note that both cross-chip
+ * notifiers and drivers have implicit assumptions about user-to-CPU-port
+ * mappings, so we unfortunately cannot delay the deletion of the objects
+ * (switchdev, standalone addresses, standalone VLANs) on the old CPU port
+ * until the new CPU port has been set up. So we need to completely tear down
+ * the old CPU port before changing it, and restore it on errors during the
+ * bringup of the new one.
+ */
+int dsa_port_change_master(struct dsa_port *dp, struct net_device *master,
+			   struct netlink_ext_ack *extack)
+{
+	struct net_device *bridge_dev = dsa_port_bridge_dev_get(dp);
+	struct net_device *old_master = dsa_port_to_master(dp);
+	struct net_device *dev = dp->slave;
+	struct dsa_switch *ds = dp->ds;
+	bool vlan_filtering;
+	int err, tmp;
+
+	/* Bridges may hold host FDB, MDB and VLAN objects. These need to be
+	 * migrated, so dynamically unoffload and later reoffload the bridge
+	 * port.
+	 */
+	if (bridge_dev) {
+		dsa_port_pre_bridge_leave(dp, bridge_dev);
+		dsa_port_bridge_leave(dp, bridge_dev);
+	}
+
+	/* The port might still be VLAN filtering even if it's no longer
+	 * under a bridge, either due to ds->vlan_filtering_is_global or
+	 * ds->needs_standalone_vlan_filtering. In turn this means VLANs
+	 * on the CPU port.
+	 */
+	vlan_filtering = dsa_port_is_vlan_filtering(dp);
+	if (vlan_filtering) {
+		err = dsa_slave_manage_vlan_filtering(dev, false);
+		if (err) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Failed to remove standalone VLANs");
+			goto rewind_old_bridge;
+		}
+	}
+
+	/* Standalone addresses, and addresses of upper interfaces like
+	 * VLAN, LAG, HSR need to be migrated.
+	 */
+	dsa_slave_unsync_ha(dev);
+
+	err = dsa_port_assign_master(dp, master, extack, true);
+	if (err)
+		goto rewind_old_addrs;
+
+	dsa_slave_sync_ha(dev);
+
+	if (vlan_filtering) {
+		err = dsa_slave_manage_vlan_filtering(dev, true);
+		if (err) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Failed to restore standalone VLANs");
+			goto rewind_new_addrs;
+		}
+	}
+
+	if (bridge_dev) {
+		err = dsa_port_bridge_join(dp, bridge_dev, extack);
+		if (err && err == -EOPNOTSUPP) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Failed to reoffload bridge");
+			goto rewind_new_vlan;
+		}
+	}
+
+	return 0;
+
+rewind_new_vlan:
+	if (vlan_filtering)
+		dsa_slave_manage_vlan_filtering(dev, false);
+
+rewind_new_addrs:
+	dsa_slave_unsync_ha(dev);
+
+	dsa_port_assign_master(dp, old_master, NULL, false);
+
+/* Restore the objects on the old CPU port */
+rewind_old_addrs:
+	dsa_slave_sync_ha(dev);
+
+	if (vlan_filtering) {
+		tmp = dsa_slave_manage_vlan_filtering(dev, true);
+		if (tmp) {
+			dev_err(ds->dev,
+				"port %d failed to restore standalone VLANs: %pe\n",
+				dp->index, ERR_PTR(tmp));
+		}
+	}
+
+rewind_old_bridge:
+	if (bridge_dev) {
+		tmp = dsa_port_bridge_join(dp, bridge_dev, extack);
+		if (tmp) {
+			dev_err(ds->dev,
+				"port %d failed to rejoin bridge %s: %pe\n",
+				dp->index, bridge_dev->name, ERR_PTR(tmp));
+		}
+	}
+
+	return err;
+}
+
 void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
 			       const struct dsa_device_ops *tag_ops)
 {
@@ -1529,6 +1661,7 @@ int dsa_port_phylink_create(struct dsa_port *dp)
 {
 	struct dsa_switch *ds = dp->ds;
 	phy_interface_t mode;
+	struct phylink *pl;
 	int err;
 
 	err = of_get_phy_mode(dp->dn, &mode);
@@ -1545,17 +1678,25 @@ int dsa_port_phylink_create(struct dsa_port *dp)
 	if (ds->ops->phylink_get_caps)
 		ds->ops->phylink_get_caps(ds, dp->index, &dp->pl_config);
 
-	dp->pl = phylink_create(&dp->pl_config, of_fwnode_handle(dp->dn),
-				mode, &dsa_port_phylink_mac_ops);
-	if (IS_ERR(dp->pl)) {
+	pl = phylink_create(&dp->pl_config, of_fwnode_handle(dp->dn),
+			    mode, &dsa_port_phylink_mac_ops);
+	if (IS_ERR(pl)) {
 		pr_err("error creating PHYLINK: %ld\n", PTR_ERR(dp->pl));
-		return PTR_ERR(dp->pl);
+		return PTR_ERR(pl);
 	}
 
+	dp->pl = pl;
+
 	return 0;
 }
 
-static int dsa_port_setup_phy_of(struct dsa_port *dp, bool enable)
+void dsa_port_phylink_destroy(struct dsa_port *dp)
+{
+	phylink_destroy(dp->pl);
+	dp->pl = NULL;
+}
+
+static int dsa_shared_port_setup_phy_of(struct dsa_port *dp, bool enable)
 {
 	struct dsa_switch *ds = dp->ds;
 	struct phy_device *phydev;
@@ -1593,7 +1734,7 @@ err_put_dev:
 	return err;
 }
 
-static int dsa_port_fixed_link_register_of(struct dsa_port *dp)
+static int dsa_shared_port_fixed_link_register_of(struct dsa_port *dp)
 {
 	struct device_node *dn = dp->dn;
 	struct dsa_switch *ds = dp->ds;
@@ -1627,7 +1768,7 @@ static int dsa_port_fixed_link_register_of(struct dsa_port *dp)
 	return 0;
 }
 
-static int dsa_port_phylink_register(struct dsa_port *dp)
+static int dsa_shared_port_phylink_register(struct dsa_port *dp)
 {
 	struct dsa_switch *ds = dp->ds;
 	struct device_node *port_dn = dp->dn;
@@ -1649,26 +1790,188 @@ static int dsa_port_phylink_register(struct dsa_port *dp)
 	return 0;
 
 err_phy_connect:
-	phylink_destroy(dp->pl);
+	dsa_port_phylink_destroy(dp);
 	return err;
 }
 
-int dsa_port_link_register_of(struct dsa_port *dp)
+/* During the initial DSA driver migration to OF, port nodes were sometimes
+ * added to device trees with no indication of how they should operate from a
+ * link management perspective (phy-handle, fixed-link, etc). Additionally, the
+ * phy-mode may be absent. The interpretation of these port OF nodes depends on
+ * their type.
+ *
+ * User ports with no phy-handle or fixed-link are expected to connect to an
+ * internal PHY located on the ds->slave_mii_bus at an MDIO address equal to
+ * the port number. This description is still actively supported.
+ *
+ * Shared (CPU and DSA) ports with no phy-handle or fixed-link are expected to
+ * operate at the maximum speed that their phy-mode is capable of. If the
+ * phy-mode is absent, they are expected to operate using the phy-mode
+ * supported by the port that gives the highest link speed. It is unspecified
+ * if the port should use flow control or not, half duplex or full duplex, or
+ * if the phy-mode is a SERDES link, whether in-band autoneg is expected to be
+ * enabled or not.
+ *
+ * In the latter case of shared ports, omitting the link management description
+ * from the firmware node is deprecated and strongly discouraged. DSA uses
+ * phylink, which rejects the firmware nodes of these ports for lacking
+ * required properties.
+ *
+ * For switches in this table, DSA will skip enforcing validation and will
+ * later omit registering a phylink instance for the shared ports, if they lack
+ * a fixed-link, a phy-handle, or a managed = "in-band-status" property.
+ * It becomes the responsibility of the driver to ensure that these ports
+ * operate at the maximum speed (whatever this means) and will interoperate
+ * with the DSA master or other cascade port, since phylink methods will not be
+ * invoked for them.
+ *
+ * If you are considering expanding this table for newly introduced switches,
+ * think again. It is OK to remove switches from this table if there aren't DT
+ * blobs in circulation which rely on defaulting the shared ports.
+ */
+static const char * const dsa_switches_apply_workarounds[] = {
+#if IS_ENABLED(CONFIG_NET_DSA_XRS700X)
+	"arrow,xrs7003e",
+	"arrow,xrs7003f",
+	"arrow,xrs7004e",
+	"arrow,xrs7004f",
+#endif
+#if IS_ENABLED(CONFIG_B53)
+	"brcm,bcm5325",
+	"brcm,bcm53115",
+	"brcm,bcm53125",
+	"brcm,bcm53128",
+	"brcm,bcm5365",
+	"brcm,bcm5389",
+	"brcm,bcm5395",
+	"brcm,bcm5397",
+	"brcm,bcm5398",
+	"brcm,bcm53010-srab",
+	"brcm,bcm53011-srab",
+	"brcm,bcm53012-srab",
+	"brcm,bcm53018-srab",
+	"brcm,bcm53019-srab",
+	"brcm,bcm5301x-srab",
+	"brcm,bcm11360-srab",
+	"brcm,bcm58522-srab",
+	"brcm,bcm58525-srab",
+	"brcm,bcm58535-srab",
+	"brcm,bcm58622-srab",
+	"brcm,bcm58623-srab",
+	"brcm,bcm58625-srab",
+	"brcm,bcm88312-srab",
+	"brcm,cygnus-srab",
+	"brcm,nsp-srab",
+	"brcm,omega-srab",
+	"brcm,bcm3384-switch",
+	"brcm,bcm6328-switch",
+	"brcm,bcm6368-switch",
+	"brcm,bcm63xx-switch",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_BCM_SF2)
+	"brcm,bcm7445-switch-v4.0",
+	"brcm,bcm7278-switch-v4.0",
+	"brcm,bcm7278-switch-v4.8",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_LANTIQ_GSWIP)
+	"lantiq,xrx200-gswip",
+	"lantiq,xrx300-gswip",
+	"lantiq,xrx330-gswip",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_MV88E6060)
+	"marvell,mv88e6060",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_MV88E6XXX)
+	"marvell,mv88e6085",
+	"marvell,mv88e6190",
+	"marvell,mv88e6250",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ_COMMON)
+	"microchip,ksz8765",
+	"microchip,ksz8794",
+	"microchip,ksz8795",
+	"microchip,ksz8863",
+	"microchip,ksz8873",
+	"microchip,ksz9477",
+	"microchip,ksz9897",
+	"microchip,ksz9893",
+	"microchip,ksz9563",
+	"microchip,ksz8563",
+	"microchip,ksz9567",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_SMSC_LAN9303_MDIO)
+	"smsc,lan9303-mdio",
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_SMSC_LAN9303_I2C)
+	"smsc,lan9303-i2c",
+#endif
+	NULL,
+};
+
+static void dsa_shared_port_validate_of(struct dsa_port *dp,
+					bool *missing_phy_mode,
+					bool *missing_link_description)
 {
+	struct device_node *dn = dp->dn, *phy_np;
 	struct dsa_switch *ds = dp->ds;
-	struct device_node *phy_np;
+	phy_interface_t mode;
+
+	*missing_phy_mode = false;
+	*missing_link_description = false;
+
+	if (of_get_phy_mode(dn, &mode)) {
+		*missing_phy_mode = true;
+		dev_err(ds->dev,
+			"OF node %pOF of %s port %d lacks the required \"phy-mode\" property\n",
+			dn, dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
+	}
+
+	/* Note: of_phy_is_fixed_link() also returns true for
+	 * managed = "in-band-status"
+	 */
+	if (of_phy_is_fixed_link(dn))
+		return;
+
+	phy_np = of_parse_phandle(dn, "phy-handle", 0);
+	if (phy_np) {
+		of_node_put(phy_np);
+		return;
+	}
+
+	*missing_link_description = true;
+
+	dev_err(ds->dev,
+		"OF node %pOF of %s port %d lacks the required \"phy-handle\", \"fixed-link\" or \"managed\" properties\n",
+		dn, dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
+}
+
+int dsa_shared_port_link_register_of(struct dsa_port *dp)
+{
+	struct dsa_switch *ds = dp->ds;
+	bool missing_link_description;
+	bool missing_phy_mode;
 	int port = dp->index;
 
+	dsa_shared_port_validate_of(dp, &missing_phy_mode,
+				    &missing_link_description);
+
+	if ((missing_phy_mode || missing_link_description) &&
+	    !of_device_compatible_match(ds->dev->of_node,
+					dsa_switches_apply_workarounds))
+		return -EINVAL;
+
 	if (!ds->ops->adjust_link) {
-		phy_np = of_parse_phandle(dp->dn, "phy-handle", 0);
-		if (of_phy_is_fixed_link(dp->dn) || phy_np) {
+		if (missing_link_description) {
+			dev_warn(ds->dev,
+				 "Skipping phylink registration for %s port %d\n",
+				 dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
+		} else {
 			if (ds->ops->phylink_mac_link_down)
 				ds->ops->phylink_mac_link_down(ds, port,
 					MLO_AN_FIXED, PHY_INTERFACE_MODE_NA);
-			of_node_put(phy_np);
-			return dsa_port_phylink_register(dp);
+
+			return dsa_shared_port_phylink_register(dp);
 		}
-		of_node_put(phy_np);
 		return 0;
 	}
 
@@ -1676,12 +1979,12 @@ int dsa_port_link_register_of(struct dsa_port *dp)
 		 "Using legacy PHYLIB callbacks. Please migrate to PHYLINK!\n");
 
 	if (of_phy_is_fixed_link(dp->dn))
-		return dsa_port_fixed_link_register_of(dp);
+		return dsa_shared_port_fixed_link_register_of(dp);
 	else
-		return dsa_port_setup_phy_of(dp, true);
+		return dsa_shared_port_setup_phy_of(dp, true);
 }
 
-void dsa_port_link_unregister_of(struct dsa_port *dp)
+void dsa_shared_port_link_unregister_of(struct dsa_port *dp)
 {
 	struct dsa_switch *ds = dp->ds;
 
@@ -1689,15 +1992,14 @@ void dsa_port_link_unregister_of(struct dsa_port *dp)
 		rtnl_lock();
 		phylink_disconnect_phy(dp->pl);
 		rtnl_unlock();
-		phylink_destroy(dp->pl);
-		dp->pl = NULL;
+		dsa_port_phylink_destroy(dp);
 		return;
 	}
 
 	if (of_phy_is_fixed_link(dp->dn))
 		of_phy_deregister_fixed_link(dp->dn);
 	else
-		dsa_port_setup_phy_of(dp, false);
+		dsa_shared_port_setup_phy_of(dp, false);
 }
 
 int dsa_port_hsr_join(struct dsa_port *dp, struct net_device *hsr)
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 1291c2431d44..1a59918d3b30 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -164,6 +164,48 @@ static int dsa_slave_unsync_mc(struct net_device *dev,
 	return dsa_slave_schedule_standalone_work(dev, DSA_MC_DEL, addr, 0);
 }
 
+void dsa_slave_sync_ha(struct net_device *dev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
+	struct netdev_hw_addr *ha;
+
+	netif_addr_lock_bh(dev);
+
+	netdev_for_each_synced_mc_addr(ha, dev)
+		dsa_slave_sync_mc(dev, ha->addr);
+
+	netdev_for_each_synced_uc_addr(ha, dev)
+		dsa_slave_sync_uc(dev, ha->addr);
+
+	netif_addr_unlock_bh(dev);
+
+	if (dsa_switch_supports_uc_filtering(ds) ||
+	    dsa_switch_supports_mc_filtering(ds))
+		dsa_flush_workqueue();
+}
+
+void dsa_slave_unsync_ha(struct net_device *dev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
+	struct netdev_hw_addr *ha;
+
+	netif_addr_lock_bh(dev);
+
+	netdev_for_each_synced_uc_addr(ha, dev)
+		dsa_slave_unsync_uc(dev, ha->addr);
+
+	netdev_for_each_synced_mc_addr(ha, dev)
+		dsa_slave_unsync_mc(dev, ha->addr);
+
+	netif_addr_unlock_bh(dev);
+
+	if (dsa_switch_supports_uc_filtering(ds) ||
+	    dsa_switch_supports_mc_filtering(ds))
+		dsa_flush_workqueue();
+}
+
 /* slave mii_bus handling ***************************************************/
 static int dsa_slave_phy_read(struct mii_bus *bus, int addr, int reg)
 {
@@ -826,9 +868,9 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 static void dsa_slave_get_drvinfo(struct net_device *dev,
 				  struct ethtool_drvinfo *drvinfo)
 {
-	strlcpy(drvinfo->driver, "dsa", sizeof(drvinfo->driver));
-	strlcpy(drvinfo->fw_version, "N/A", sizeof(drvinfo->fw_version));
-	strlcpy(drvinfo->bus_info, "platform", sizeof(drvinfo->bus_info));
+	strscpy(drvinfo->driver, "dsa", sizeof(drvinfo->driver));
+	strscpy(drvinfo->fw_version, "N/A", sizeof(drvinfo->fw_version));
+	strscpy(drvinfo->bus_info, "platform", sizeof(drvinfo->bus_info));
 }
 
 static int dsa_slave_get_regs_len(struct net_device *dev)
@@ -1503,8 +1545,7 @@ static int dsa_slave_setup_tc_block(struct net_device *dev,
 static int dsa_slave_setup_ft_block(struct dsa_switch *ds, int port,
 				    void *type_data)
 {
-	struct dsa_port *cpu_dp = dsa_to_port(ds, port)->cpu_dp;
-	struct net_device *master = cpu_dp->master;
+	struct net_device *master = dsa_port_to_master(dsa_to_port(ds, port));
 
 	if (!master->netdev_ops->ndo_setup_tc)
 		return -EOPNOTSUPP;
@@ -2147,13 +2188,14 @@ static int dsa_slave_fill_forward_path(struct net_device_path_ctx *ctx,
 				       struct net_device_path *path)
 {
 	struct dsa_port *dp = dsa_slave_to_port(ctx->dev);
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_port *cpu_dp = dp->cpu_dp;
 
 	path->dev = ctx->dev;
 	path->type = DEV_PATH_DSA;
 	path->dsa.proto = cpu_dp->tag_ops->proto;
 	path->dsa.port = dp->index;
-	ctx->dev = cpu_dp->master;
+	ctx->dev = master;
 
 	return 0;
 }
@@ -2262,7 +2304,7 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev)
 	if (ret) {
 		netdev_err(slave_dev, "failed to connect to PHY: %pe\n",
 			   ERR_PTR(ret));
-		phylink_destroy(dp->pl);
+		dsa_port_phylink_destroy(dp);
 	}
 
 	return ret;
@@ -2271,9 +2313,9 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev)
 void dsa_slave_setup_tagger(struct net_device *slave)
 {
 	struct dsa_port *dp = dsa_slave_to_port(slave);
+	struct net_device *master = dsa_port_to_master(dp);
 	struct dsa_slave_priv *p = netdev_priv(slave);
 	const struct dsa_port *cpu_dp = dp->cpu_dp;
-	struct net_device *master = cpu_dp->master;
 	const struct dsa_switch *ds = dp->ds;
 
 	slave->needed_headroom = cpu_dp->tag_ops->needed_headroom;
@@ -2330,8 +2372,7 @@ int dsa_slave_resume(struct net_device *slave_dev)
 
 int dsa_slave_create(struct dsa_port *port)
 {
-	const struct dsa_port *cpu_dp = port->cpu_dp;
-	struct net_device *master = cpu_dp->master;
+	struct net_device *master = dsa_port_to_master(port);
 	struct dsa_switch *ds = port->ds;
 	const char *name = port->name;
 	struct net_device *slave_dev;
@@ -2347,6 +2388,7 @@ int dsa_slave_create(struct dsa_port *port)
 	if (slave_dev == NULL)
 		return -ENOMEM;
 
+	slave_dev->rtnl_link_ops = &dsa_link_ops;
 	slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;
 #if IS_ENABLED(CONFIG_DCB)
 	slave_dev->dcbnl_ops = &dsa_slave_dcbnl_ops;
@@ -2434,7 +2476,7 @@ out_phy:
 	rtnl_lock();
 	phylink_disconnect_phy(p->dp->pl);
 	rtnl_unlock();
-	phylink_destroy(p->dp->pl);
+	dsa_port_phylink_destroy(p->dp);
 out_gcells:
 	gro_cells_destroy(&p->gcells);
 out_free:
@@ -2457,12 +2499,89 @@ void dsa_slave_destroy(struct net_device *slave_dev)
 	phylink_disconnect_phy(dp->pl);
 	rtnl_unlock();
 
-	phylink_destroy(dp->pl);
+	dsa_port_phylink_destroy(dp);
 	gro_cells_destroy(&p->gcells);
 	free_percpu(slave_dev->tstats);
 	free_netdev(slave_dev);
 }
 
+int dsa_slave_change_master(struct net_device *dev, struct net_device *master,
+			    struct netlink_ext_ack *extack)
+{
+	struct net_device *old_master = dsa_slave_to_master(dev);
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
+	struct net_device *upper;
+	struct list_head *iter;
+	int err;
+
+	if (master == old_master)
+		return 0;
+
+	if (!ds->ops->port_change_master) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Driver does not support changing DSA master");
+		return -EOPNOTSUPP;
+	}
+
+	if (!netdev_uses_dsa(master)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Interface not eligible as DSA master");
+		return -EOPNOTSUPP;
+	}
+
+	netdev_for_each_upper_dev_rcu(master, upper, iter) {
+		if (dsa_slave_dev_check(upper))
+			continue;
+		if (netif_is_bridge_master(upper))
+			continue;
+		NL_SET_ERR_MSG_MOD(extack, "Cannot join master with unknown uppers");
+		return -EOPNOTSUPP;
+	}
+
+	/* Since we allow live-changing the DSA master, plus we auto-open the
+	 * DSA master when the user port opens => we need to ensure that the
+	 * new DSA master is open too.
+	 */
+	if (dev->flags & IFF_UP) {
+		err = dev_open(master, extack);
+		if (err)
+			return err;
+	}
+
+	netdev_upper_dev_unlink(old_master, dev);
+
+	err = netdev_upper_dev_link(master, dev, extack);
+	if (err)
+		goto out_revert_old_master_unlink;
+
+	err = dsa_port_change_master(dp, master, extack);
+	if (err)
+		goto out_revert_master_link;
+
+	/* Update the MTU of the new CPU port through cross-chip notifiers */
+	err = dsa_slave_change_mtu(dev, dev->mtu);
+	if (err && err != -EOPNOTSUPP) {
+		netdev_warn(dev,
+			    "nonfatal error updating MTU with new master: %pe\n",
+			    ERR_PTR(err));
+	}
+
+	/* If the port doesn't have its own MAC address and relies on the DSA
+	 * master's one, inherit it again from the new DSA master.
+	 */
+	if (is_zero_ether_addr(dp->mac))
+		eth_hw_addr_inherit(dev, master);
+
+	return 0;
+
+out_revert_master_link:
+	netdev_upper_dev_unlink(master, dev);
+out_revert_old_master_unlink:
+	netdev_upper_dev_link(old_master, dev, NULL);
+	return err;
+}
+
 bool dsa_slave_dev_check(const struct net_device *dev)
 {
 	return dev->netdev_ops == &dsa_slave_netdev_ops;
@@ -2476,6 +2595,9 @@ static int dsa_slave_changeupper(struct net_device *dev,
 	struct netlink_ext_ack *extack;
 	int err = NOTIFY_DONE;
 
+	if (!dsa_slave_dev_check(dev))
+		return err;
+
 	extack = netdev_notifier_info_to_extack(&info->info);
 
 	if (netif_is_bridge_master(info->upper_dev)) {
@@ -2531,6 +2653,9 @@ static int dsa_slave_prechangeupper(struct net_device *dev,
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 
+	if (!dsa_slave_dev_check(dev))
+		return NOTIFY_DONE;
+
 	if (netif_is_bridge_master(info->upper_dev) && !info->linking)
 		dsa_port_pre_bridge_leave(dp, info->upper_dev);
 	else if (netif_is_lag_master(info->upper_dev) && !info->linking)
@@ -2551,6 +2676,9 @@ dsa_slave_lag_changeupper(struct net_device *dev,
 	int err = NOTIFY_DONE;
 	struct dsa_port *dp;
 
+	if (!netif_is_lag_master(dev))
+		return err;
+
 	netdev_for_each_lower_dev(dev, lower, iter) {
 		if (!dsa_slave_dev_check(lower))
 			continue;
@@ -2580,6 +2708,9 @@ dsa_slave_lag_prechangeupper(struct net_device *dev,
 	int err = NOTIFY_DONE;
 	struct dsa_port *dp;
 
+	if (!netif_is_lag_master(dev))
+		return err;
+
 	netdev_for_each_lower_dev(dev, lower, iter) {
 		if (!dsa_slave_dev_check(lower))
 			continue;
@@ -2687,6 +2818,277 @@ dsa_slave_prechangeupper_sanity_check(struct net_device *dev,
 	return NOTIFY_DONE;
 }
 
+/* To be eligible as a DSA master, a LAG must have all lower interfaces be
+ * eligible DSA masters. Additionally, all LAG slaves must be DSA masters of
+ * switches in the same switch tree.
+ */
+static int dsa_lag_master_validate(struct net_device *lag_dev,
+				   struct netlink_ext_ack *extack)
+{
+	struct net_device *lower1, *lower2;
+	struct list_head *iter1, *iter2;
+
+	netdev_for_each_lower_dev(lag_dev, lower1, iter1) {
+		netdev_for_each_lower_dev(lag_dev, lower2, iter2) {
+			if (!netdev_uses_dsa(lower1) ||
+			    !netdev_uses_dsa(lower2)) {
+				NL_SET_ERR_MSG_MOD(extack,
+						   "All LAG ports must be eligible as DSA masters");
+				return notifier_from_errno(-EINVAL);
+			}
+
+			if (lower1 == lower2)
+				continue;
+
+			if (!dsa_port_tree_same(lower1->dsa_ptr,
+						lower2->dsa_ptr)) {
+				NL_SET_ERR_MSG_MOD(extack,
+						   "LAG contains DSA masters of disjoint switch trees");
+				return notifier_from_errno(-EINVAL);
+			}
+		}
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int
+dsa_master_prechangeupper_sanity_check(struct net_device *master,
+				       struct netdev_notifier_changeupper_info *info)
+{
+	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(&info->info);
+
+	if (!netdev_uses_dsa(master))
+		return NOTIFY_DONE;
+
+	if (!info->linking)
+		return NOTIFY_DONE;
+
+	/* Allow DSA switch uppers */
+	if (dsa_slave_dev_check(info->upper_dev))
+		return NOTIFY_DONE;
+
+	/* Allow bridge uppers of DSA masters, subject to further
+	 * restrictions in dsa_bridge_prechangelower_sanity_check()
+	 */
+	if (netif_is_bridge_master(info->upper_dev))
+		return NOTIFY_DONE;
+
+	/* Allow LAG uppers, subject to further restrictions in
+	 * dsa_lag_master_prechangelower_sanity_check()
+	 */
+	if (netif_is_lag_master(info->upper_dev))
+		return dsa_lag_master_validate(info->upper_dev, extack);
+
+	NL_SET_ERR_MSG_MOD(extack,
+			   "DSA master cannot join unknown upper interfaces");
+	return notifier_from_errno(-EBUSY);
+}
+
+static int
+dsa_lag_master_prechangelower_sanity_check(struct net_device *dev,
+					   struct netdev_notifier_changeupper_info *info)
+{
+	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(&info->info);
+	struct net_device *lag_dev = info->upper_dev;
+	struct net_device *lower;
+	struct list_head *iter;
+
+	if (!netdev_uses_dsa(lag_dev) || !netif_is_lag_master(lag_dev))
+		return NOTIFY_DONE;
+
+	if (!info->linking)
+		return NOTIFY_DONE;
+
+	if (!netdev_uses_dsa(dev)) {
+		NL_SET_ERR_MSG(extack,
+			       "Only DSA masters can join a LAG DSA master");
+		return notifier_from_errno(-EINVAL);
+	}
+
+	netdev_for_each_lower_dev(lag_dev, lower, iter) {
+		if (!dsa_port_tree_same(dev->dsa_ptr, lower->dsa_ptr)) {
+			NL_SET_ERR_MSG(extack,
+				       "Interface is DSA master for a different switch tree than this LAG");
+			return notifier_from_errno(-EINVAL);
+		}
+
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+/* Don't allow bridging of DSA masters, since the bridge layer rx_handler
+ * prevents the DSA fake ethertype handler to be invoked, so we don't get the
+ * chance to strip off and parse the DSA switch tag protocol header (the bridge
+ * layer just returns RX_HANDLER_CONSUMED, stopping RX processing for these
+ * frames).
+ * The only case where that would not be an issue is when bridging can already
+ * be offloaded, such as when the DSA master is itself a DSA or plain switchdev
+ * port, and is bridged only with other ports from the same hardware device.
+ */
+static int
+dsa_bridge_prechangelower_sanity_check(struct net_device *new_lower,
+				       struct netdev_notifier_changeupper_info *info)
+{
+	struct net_device *br = info->upper_dev;
+	struct netlink_ext_ack *extack;
+	struct net_device *lower;
+	struct list_head *iter;
+
+	if (!netif_is_bridge_master(br))
+		return NOTIFY_DONE;
+
+	if (!info->linking)
+		return NOTIFY_DONE;
+
+	extack = netdev_notifier_info_to_extack(&info->info);
+
+	netdev_for_each_lower_dev(br, lower, iter) {
+		if (!netdev_uses_dsa(new_lower) && !netdev_uses_dsa(lower))
+			continue;
+
+		if (!netdev_port_same_parent_id(lower, new_lower)) {
+			NL_SET_ERR_MSG(extack,
+				       "Cannot do software bridging with a DSA master");
+			return notifier_from_errno(-EINVAL);
+		}
+	}
+
+	return NOTIFY_DONE;
+}
+
+static void dsa_tree_migrate_ports_from_lag_master(struct dsa_switch_tree *dst,
+						   struct net_device *lag_dev)
+{
+	struct net_device *new_master = dsa_tree_find_first_master(dst);
+	struct dsa_port *dp;
+	int err;
+
+	dsa_tree_for_each_user_port(dp, dst) {
+		if (dsa_port_to_master(dp) != lag_dev)
+			continue;
+
+		err = dsa_slave_change_master(dp->slave, new_master, NULL);
+		if (err) {
+			netdev_err(dp->slave,
+				   "failed to restore master to %s: %pe\n",
+				   new_master->name, ERR_PTR(err));
+		}
+	}
+}
+
+static int dsa_master_lag_join(struct net_device *master,
+			       struct net_device *lag_dev,
+			       struct netdev_lag_upper_info *uinfo,
+			       struct netlink_ext_ack *extack)
+{
+	struct dsa_port *cpu_dp = master->dsa_ptr;
+	struct dsa_switch_tree *dst = cpu_dp->dst;
+	struct dsa_port *dp;
+	int err;
+
+	err = dsa_master_lag_setup(lag_dev, cpu_dp, uinfo, extack);
+	if (err)
+		return err;
+
+	dsa_tree_for_each_user_port(dp, dst) {
+		if (dsa_port_to_master(dp) != master)
+			continue;
+
+		err = dsa_slave_change_master(dp->slave, lag_dev, extack);
+		if (err)
+			goto restore;
+	}
+
+	return 0;
+
+restore:
+	dsa_tree_for_each_user_port_continue_reverse(dp, dst) {
+		if (dsa_port_to_master(dp) != lag_dev)
+			continue;
+
+		err = dsa_slave_change_master(dp->slave, master, NULL);
+		if (err) {
+			netdev_err(dp->slave,
+				   "failed to restore master to %s: %pe\n",
+				   master->name, ERR_PTR(err));
+		}
+	}
+
+	dsa_master_lag_teardown(lag_dev, master->dsa_ptr);
+
+	return err;
+}
+
+static void dsa_master_lag_leave(struct net_device *master,
+				 struct net_device *lag_dev)
+{
+	struct dsa_port *dp, *cpu_dp = lag_dev->dsa_ptr;
+	struct dsa_switch_tree *dst = cpu_dp->dst;
+	struct dsa_port *new_cpu_dp = NULL;
+	struct net_device *lower;
+	struct list_head *iter;
+
+	netdev_for_each_lower_dev(lag_dev, lower, iter) {
+		if (netdev_uses_dsa(lower)) {
+			new_cpu_dp = lower->dsa_ptr;
+			break;
+		}
+	}
+
+	if (new_cpu_dp) {
+		/* Update the CPU port of the user ports still under the LAG
+		 * so that dsa_port_to_master() continues to work properly
+		 */
+		dsa_tree_for_each_user_port(dp, dst)
+			if (dsa_port_to_master(dp) == lag_dev)
+				dp->cpu_dp = new_cpu_dp;
+
+		/* Update the index of the virtual CPU port to match the lowest
+		 * physical CPU port
+		 */
+		lag_dev->dsa_ptr = new_cpu_dp;
+		wmb();
+	} else {
+		/* If the LAG DSA master has no ports left, migrate back all
+		 * user ports to the first physical CPU port
+		 */
+		dsa_tree_migrate_ports_from_lag_master(dst, lag_dev);
+	}
+
+	/* This DSA master has left its LAG in any case, so let
+	 * the CPU port leave the hardware LAG as well
+	 */
+	dsa_master_lag_teardown(lag_dev, master->dsa_ptr);
+}
+
+static int dsa_master_changeupper(struct net_device *dev,
+				  struct netdev_notifier_changeupper_info *info)
+{
+	struct netlink_ext_ack *extack;
+	int err = NOTIFY_DONE;
+
+	if (!netdev_uses_dsa(dev))
+		return err;
+
+	extack = netdev_notifier_info_to_extack(&info->info);
+
+	if (netif_is_lag_master(info->upper_dev)) {
+		if (info->linking) {
+			err = dsa_master_lag_join(dev, info->upper_dev,
+						  info->upper_info, extack);
+			err = notifier_from_errno(err);
+		} else {
+			dsa_master_lag_leave(dev, info->upper_dev);
+			err = NOTIFY_OK;
+		}
+	}
+
+	return err;
+}
+
 static int dsa_slave_netdevice_event(struct notifier_block *nb,
 				     unsigned long event, void *ptr)
 {
@@ -2698,36 +3100,68 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
 		int err;
 
 		err = dsa_slave_prechangeupper_sanity_check(dev, info);
-		if (err != NOTIFY_DONE)
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_master_prechangeupper_sanity_check(dev, info);
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_lag_master_prechangelower_sanity_check(dev, info);
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_bridge_prechangelower_sanity_check(dev, info);
+		if (notifier_to_errno(err))
 			return err;
 
-		if (dsa_slave_dev_check(dev))
-			return dsa_slave_prechangeupper(dev, ptr);
+		err = dsa_slave_prechangeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
 
-		if (netif_is_lag_master(dev))
-			return dsa_slave_lag_prechangeupper(dev, ptr);
+		err = dsa_slave_lag_prechangeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
 
 		break;
 	}
-	case NETDEV_CHANGEUPPER:
-		if (dsa_slave_dev_check(dev))
-			return dsa_slave_changeupper(dev, ptr);
+	case NETDEV_CHANGEUPPER: {
+		int err;
 
-		if (netif_is_lag_master(dev))
-			return dsa_slave_lag_changeupper(dev, ptr);
+		err = dsa_slave_changeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_slave_lag_changeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
+
+		err = dsa_master_changeupper(dev, ptr);
+		if (notifier_to_errno(err))
+			return err;
 
 		break;
+	}
 	case NETDEV_CHANGELOWERSTATE: {
 		struct netdev_notifier_changelowerstate_info *info = ptr;
 		struct dsa_port *dp;
 		int err;
 
-		if (!dsa_slave_dev_check(dev))
-			break;
+		if (dsa_slave_dev_check(dev)) {
+			dp = dsa_slave_to_port(dev);
 
-		dp = dsa_slave_to_port(dev);
+			err = dsa_port_lag_change(dp, info->lower_state_info);
+		}
+
+		/* Mirror LAG port events on DSA masters that are in
+		 * a LAG towards their respective switch CPU ports
+		 */
+		if (netdev_uses_dsa(dev)) {
+			dp = dev->dsa_ptr;
+
+			err = dsa_port_lag_change(dp, info->lower_state_info);
+		}
 
-		err = dsa_port_lag_change(dp, info->lower_state_info);
 		return notifier_from_errno(err);
 	}
 	case NETDEV_CHANGE:
@@ -2777,6 +3211,9 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
 			if (!dsa_port_is_user(dp))
 				continue;
 
+			if (dp->cpu_dp != cpu_dp)
+				continue;
+
 			list_add(&dp->slave->close_list, &close_list);
 		}
 
diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index 4dfd68cf61c5..ce56acdba203 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -398,8 +398,15 @@ static int dsa_switch_host_fdb_add(struct dsa_switch *ds,
 
 	dsa_switch_for_each_port(dp, ds) {
 		if (dsa_port_host_address_match(dp, info->dp)) {
-			err = dsa_port_do_fdb_add(dp, info->addr, info->vid,
-						  info->db);
+			if (dsa_port_is_cpu(dp) && info->dp->cpu_port_in_lag) {
+				err = dsa_switch_do_lag_fdb_add(ds, dp->lag,
+								info->addr,
+								info->vid,
+								info->db);
+			} else {
+				err = dsa_port_do_fdb_add(dp, info->addr,
+							  info->vid, info->db);
+			}
 			if (err)
 				break;
 		}
@@ -419,8 +426,15 @@ static int dsa_switch_host_fdb_del(struct dsa_switch *ds,
 
 	dsa_switch_for_each_port(dp, ds) {
 		if (dsa_port_host_address_match(dp, info->dp)) {
-			err = dsa_port_do_fdb_del(dp, info->addr, info->vid,
-						  info->db);
+			if (dsa_port_is_cpu(dp) && info->dp->cpu_port_in_lag) {
+				err = dsa_switch_do_lag_fdb_del(ds, dp->lag,
+								info->addr,
+								info->vid,
+								info->db);
+			} else {
+				err = dsa_port_do_fdb_del(dp, info->addr,
+							  info->vid, info->db);
+			}
 			if (err)
 				break;
 		}
@@ -507,12 +521,12 @@ static int dsa_switch_lag_join(struct dsa_switch *ds,
 {
 	if (info->dp->ds == ds && ds->ops->port_lag_join)
 		return ds->ops->port_lag_join(ds, info->dp->index, info->lag,
-					      info->info);
+					      info->info, info->extack);
 
 	if (info->dp->ds != ds && ds->ops->crosschip_lag_join)
 		return ds->ops->crosschip_lag_join(ds, info->dp->ds->index,
 						   info->dp->index, info->lag,
-						   info->info);
+						   info->info, info->extack);
 
 	return -EOPNOTSUPP;
 }
diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index 01a427800797..34e5ec5d3e23 100644
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -2,9 +2,7 @@
 /* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
  *
  * This module is not a complete tagger implementation. It only provides
- * primitives for taggers that rely on 802.1Q VLAN tags to use. The
- * dsa_8021q_netdev_ops is registered for API compliance and not used
- * directly by callers.
+ * primitives for taggers that rely on 802.1Q VLAN tags to use.
  */
 #include <linux/if_vlan.h>
 #include <linux/dsa/8021q.h>
@@ -332,7 +330,7 @@ static int dsa_tag_8021q_port_setup(struct dsa_switch *ds, int port)
 	if (!dsa_port_is_user(dp))
 		return 0;
 
-	master = dp->cpu_dp->master;
+	master = dsa_port_to_master(dp);
 
 	err = dsa_port_tag_8021q_vlan_add(dp, vid, false);
 	if (err) {
@@ -361,7 +359,7 @@ static void dsa_tag_8021q_port_teardown(struct dsa_switch *ds, int port)
 	if (!dsa_port_is_user(dp))
 		return;
 
-	master = dp->cpu_dp->master;
+	master = dsa_port_to_master(dp);
 
 	dsa_port_tag_8021q_vlan_del(dp, vid, false);