Linux Ethernet Bridging - Mar 2022 - [Bridge] [PATCH v5 net-next 04/15] net: bridge: mst: Notify switchdev drivers of MST mode changes

The bridge has had per-VLAN STP support for a while now, since:

https://lore.kernel.org/netdev/20200124114022.10883-1-nikolay at
cumulusnetworks.com/

The current implementation has some problems:

- The mapping from VLAN to STP state is fixed as 1:1, i.e. each VLAN
  is managed independently. This is awkward from an MSTP (802.1Q-2018,
  Clause 13.5) point of view, where the model is that multiple VLANs
  are grouped into MST instances.

  Because of the way that the standard is written, presumably, this is
  also reflected in hardware implementations. It is not uncommon for a
  switch to support the full 4k range of VIDs, but that the pool of
  MST instances is much smaller. Some examples:

  Marvell LinkStreet (mv88e6xxx): 4k VLANs, but only 64 MSTIs
  Marvell Prestera: 4k VLANs, but only 128 MSTIs
  Microchip SparX-5i: 4k VLANs, but only 128 MSTIs

- By default, the feature is enabled, and there is no way to disable
  it. This makes it hard to add offloading in a backwards compatible
  way, since any underlying switchdevs have no way to refuse the
  function if the hardware does not support it

- The port-global STP state has precedence over per-VLAN states. In
  MSTP, as far as I understand it, all VLANs will use the common
  spanning tree (CST) by default - through traffic engineering you can
  then optimize your network to group subsets of VLANs to use
  different trees (MSTI). To my understanding, the way this is
  typically managed in silicon is roughly:

  Incoming packet:
  .----.----.--------------.----.-------------
  | DA | SA | 802.1Q VID=X | ET | Payload ...
  '----'----'--------------'----'-------------
                        |
                        '->|\     .----------------------------.
                           | +--> | VID | Members | ... | MSTI |
                   PVID -->|/     |-----|---------|-----|------|
                                  |   1 | 0001001 | ... |    0 |
                                  |   2 | 0001010 | ... |   10 |
                                  |   3 | 0001100 | ... |   10 |
                                  '----------------------------'
                                                             |
                               .-----------------------------'
                               |  .------------------------.
                               '->| MSTI | Fwding | Lrning |
                                  |------|--------|--------|
                                  |    0 | 111110 | 111110 |
                                  |   10 | 110111 | 110111 |
                                  '------------------------'

  What this is trying to show is that the STP state (whether MSTP is
  used, or ye olde STP) is always accessed via the VLAN table. If STP
  is running, all MSTI pointers in that table will reference the same
  index in the STP stable - if MSTP is running, some VLANs may point
  to other trees (like in this example).

  The fact that in the Linux bridge, the global state (think: index 0
  in most hardware implementations) is supposed to override the
  per-VLAN state, is very awkward to offload. In effect, this means
  that when the global state changes to blocking, drivers will have to
  iterate over all MSTIs in use, and alter them all to match. This
  also means that you have to cache whether the hardware state is
  currently tracking the global state or the per-VLAN state. In the
  first case, you also have to cache the per-VLAN state so that you
  can restore it if the global state transitions back to forwarding.

This series adds a new mst_enable bridge setting (as suggested by Nik)
that can only be changed when no VLANs are configured on the
bridge. Enabling this mode has the following effect:

- The port-global STP state is used to represent the CST (Common
  Spanning Tree) (1/15)

- Ingress STP filtering is deferred until the frame's VLAN has been
  resolved (1/15)

- The preexisting per-VLAN states can no longer be controlled directly
  (1/15). They are instead placed under the MST module's control,
  which is managed using a new netlink interface (described in 3/15)

- VLANs can br mapped to MSTIs in an arbitrary M:N fashion, using a
  new global VLAN option (2/15)

Switchdev notifications are added so that a driver can track:
- MST enabled state
- VID to MSTI mappings
- MST port states

An offloading implementation is this provided for mv88e6xxx.

A proposal for the corresponding iproute2 interface is available here:

https://github.com/wkz/iproute2/tree/mst

v4 -> v5:
  Bridge:
  - Fix build error in intermediate commit (Jakub)
  - Use rcu safe list iterator in br_mst_info_size (Nik)
  - Propagate any errors back to the caller when changing an MST state
    (Vladimir)
  DSA:
  - Boolean algebra workshop (Vladimir, feat. De Morgan)
  - Only flush FDBs on ports when transitioning from
    forwarding/learning to listening/blocking/disabled (Vladimir)

v3 -> v4:
  Bridge:
  - Constify arguments where possible (Nik)
  - Use non-atomic bitmap operators (Nik)
  - Rename br_mst_parse -> br_mst_process (Nik)
  - Account for the dynamic size of generated MST netlink data (Nik)
  - Provide proper error reporting on invalid input (Nik)
  - Export bridge helpers under GPL (Nik)
  - Fix build when bridge VLAN filtering is compiled out (Intel bot)
  - Allocate VLAN bitmaps on the stack (Vladimir)
  DSA:
  - Propagate MST state change errors back to the bridge layer
    (Vladimir)
  - Fix issue with software fallback (Vladimir)
  - Ignore FDB events on software bridged ports
  mv88e6xxx:
  - Use non-atomic bitmap operators (Vladimir)
  - Restore refcount in error path (Vladimir)

v2 -> v3:
  Bridge:
  - Use new boolopt API to enable/disable the MST mode (Nik)
  - Mark br_mst_vlan_set_state as static (Vladimir)
  - Avoid updates/notifications on repeated VLAN to MSTI mapping
    configurations (Vladimir)
  - Configure MSTI states via the existing RTM_GET/SETLINK interface
    (Roopa)
  - Refactor switchdev replay logic (Vladimir)
  - Send switchdev notifications when enabling/disabling MST
    (Vladimir)
  DSA:
  - Align VLAN MSTI callback with existing APIs (Vladimir)
  - Only flush entries in the affected VLANs when changing an MST
    state (Vladimir)
  - Refuse offloading, unless all required ops are implemented
    (Vladimir)
  mv88e6xxx:
  - Always keep the driver's MST state in sync with hardware
    (Vladimir)
  - Fix SID leaks (Vladimir)
  - Only flush entries in the affected VLANs when changing an MST
    state (Vladimir)

v1 (RFC) -> v2:
  - Add a separate MST mode that is distinct from the exiting per-VLAN
    state functionality
  - Control MSTI states explicitly, rather than via an associated VLAN

Tobias Waldekranz (15):
  net: bridge: mst: Multiple Spanning Tree (MST) mode
  net: bridge: mst: Allow changing a VLAN's MSTI
  net: bridge: mst: Support setting and reporting MST port states
  net: bridge: mst: Notify switchdev drivers of MST mode changes
  net: bridge: mst: Notify switchdev drivers of VLAN MSTI migrations
  net: bridge: mst: Notify switchdev drivers of MST state changes
  net: bridge: mst: Add helper to map an MSTI to a VID set
  net: bridge: mst: Add helper to check if MST is enabled
  net: bridge: mst: Add helper to query a port's MST state
  net: dsa: Validate hardware support for MST
  net: dsa: Pass VLAN MSTI migration notifications to driver
  net: dsa: Handle MST state changes
  net: dsa: mv88e6xxx: Disentangle STU from VTU
  net: dsa: mv88e6xxx: Export STU as devlink region
  net: dsa: mv88e6xxx: MST Offloading

 drivers/net/dsa/mv88e6xxx/chip.c        | 304 +++++++++++++++++++-
 drivers/net/dsa/mv88e6xxx/chip.h        |  38 +++
 drivers/net/dsa/mv88e6xxx/devlink.c     |  94 +++++++
 drivers/net/dsa/mv88e6xxx/global1.h     |  10 +
 drivers/net/dsa/mv88e6xxx/global1_vtu.c | 311 ++++++++++++---------
 include/linux/if_bridge.h               |  19 ++
 include/net/dsa.h                       |   6 +
 include/net/switchdev.h                 |  16 ++
 include/uapi/linux/if_bridge.h          |  18 ++
 include/uapi/linux/rtnetlink.h          |   1 +
 net/bridge/Makefile                     |   2 +-
 net/bridge/br.c                         |   5 +
 net/bridge/br_input.c                   |  17 +-
 net/bridge/br_mst.c                     | 357 ++++++++++++++++++++++++
 net/bridge/br_netlink.c                 |  44 ++-
 net/bridge/br_private.h                 |  61 ++++
 net/bridge/br_stp.c                     |   6 +
 net/bridge/br_switchdev.c               |  46 +++
 net/bridge/br_vlan.c                    |  20 +-
 net/bridge/br_vlan_options.c            |  20 ++
 net/dsa/dsa_priv.h                      |   7 +
 net/dsa/port.c                          | 113 +++++++-
 net/dsa/slave.c                         |  18 ++
 23 files changed, 1381 insertions(+), 152 deletions(-)
 create mode 100644 net/bridge/br_mst.c

-- 
2.25.1

Allow the user to switch from the current per-VLAN STP mode to an MST
mode.

Up to this point, per-VLAN STP states where always isolated from each
other. This is in contrast to the MSTP standard (802.1Q-2018, Clause
13.5), where VLANs are grouped into MST instances (MSTIs), and the
state is managed on a per-MSTI level, rather that at the per-VLAN
level.

Perhaps due to the prevalence of the standard, many switching ASICs
are built after the same model. Therefore, add a corresponding MST
mode to the bridge, which we can later add offloading support for in a
straight-forward way.

For now, all VLANs are fixed to MSTI 0, also called the Common
Spanning Tree (CST). That is, all VLANs will follow the port-global
state.

Upcoming changes will make this actually useful by allowing VLANs to
be mapped to arbitrary MSTIs and allow individual MSTI states to be
changed.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
Acked-by: Nikolay Aleksandrov <razor at blackwall.org>
---
 include/uapi/linux/if_bridge.h |  1 +
 net/bridge/Makefile            |  2 +-
 net/bridge/br.c                |  5 ++
 net/bridge/br_input.c          | 17 ++++++-
 net/bridge/br_mst.c            | 87 ++++++++++++++++++++++++++++++++++
 net/bridge/br_private.h        | 37 +++++++++++++++
 net/bridge/br_stp.c            |  6 +++
 net/bridge/br_vlan.c           | 20 +++++++-
 net/bridge/br_vlan_options.c   |  5 ++
 9 files changed, 176 insertions(+), 4 deletions(-)
 create mode 100644 net/bridge/br_mst.c

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 2711c3522010..30a242195ced 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -759,6 +759,7 @@ struct br_mcast_stats {
 enum br_boolopt_id {
 	BR_BOOLOPT_NO_LL_LEARN,
 	BR_BOOLOPT_MCAST_VLAN_SNOOPING,
+	BR_BOOLOPT_MST_ENABLE,
 	BR_BOOLOPT_MAX
 };
 
diff --git a/net/bridge/Makefile b/net/bridge/Makefile
index 7fb9a021873b..24bd1c0a9a5a 100644
--- a/net/bridge/Makefile
+++ b/net/bridge/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_BRIDGE_NETFILTER) += br_netfilter.o
 
 bridge-$(CONFIG_BRIDGE_IGMP_SNOOPING) += br_multicast.o br_mdb.o
br_multicast_eht.o
 
-bridge-$(CONFIG_BRIDGE_VLAN_FILTERING) += br_vlan.o br_vlan_tunnel.o
br_vlan_options.o
+bridge-$(CONFIG_BRIDGE_VLAN_FILTERING) += br_vlan.o br_vlan_tunnel.o
br_vlan_options.o br_mst.o
 
 bridge-$(CONFIG_NET_SWITCHDEV) += br_switchdev.o
 
diff --git a/net/bridge/br.c b/net/bridge/br.c
index b1dea3febeea..96e91d69a9a8 100644
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -265,6 +265,9 @@ int br_boolopt_toggle(struct net_bridge *br, enum
br_boolopt_id opt, bool on,
 	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
 		err = br_multicast_toggle_vlan_snooping(br, on, extack);
 		break;
+	case BR_BOOLOPT_MST_ENABLE:
+		err = br_mst_set_enabled(br, on, extack);
+		break;
 	default:
 		/* shouldn't be called with unsupported options */
 		WARN_ON(1);
@@ -281,6 +284,8 @@ int br_boolopt_get(const struct net_bridge *br, enum
br_boolopt_id opt)
 		return br_opt_get(br, BROPT_NO_LL_LEARN);
 	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
 		return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED);
+	case BR_BOOLOPT_MST_ENABLE:
+		return br_opt_get(br, BROPT_MST_ENABLED);
 	default:
 		/* shouldn't be called with unsupported options */
 		WARN_ON(1);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index e0c13fcc50ed..196417859c4a 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -78,13 +78,22 @@ int br_handle_frame_finish(struct net *net, struct sock *sk,
struct sk_buff *skb
 	u16 vid = 0;
 	u8 state;
 
-	if (!p || p->state == BR_STATE_DISABLED)
+	if (!p)
 		goto drop;
 
 	br = p->br;
+
+	if (br_mst_is_enabled(br)) {
+		state = BR_STATE_FORWARDING;
+	} else {
+		if (p->state == BR_STATE_DISABLED)
+			goto drop;
+
+		state = p->state;
+	}
+
 	brmctx = &p->br->multicast_ctx;
 	pmctx = &p->multicast_ctx;
-	state = p->state;
 	if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid,
 				&state, &vlan))
 		goto out;
@@ -370,9 +379,13 @@ static rx_handler_result_t br_handle_frame(struct sk_buff
**pskb)
 		return RX_HANDLER_PASS;
 
 forward:
+	if (br_mst_is_enabled(p->br))
+		goto defer_stp_filtering;
+
 	switch (p->state) {
 	case BR_STATE_FORWARDING:
 	case BR_STATE_LEARNING:
+defer_stp_filtering:
 		if (ether_addr_equal(p->br->dev->dev_addr, dest))
 			skb->pkt_type = PACKET_HOST;
 
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
new file mode 100644
index 000000000000..0f9f596f86bc
--- /dev/null
+++ b/net/bridge/br_mst.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Bridge Multiple Spanning Tree Support
+ *
+ *	Authors:
+ *	Tobias Waldekranz		<tobias at waldekranz.com>
+ */
+
+#include <linux/kernel.h>
+
+#include "br_private.h"
+
+DEFINE_STATIC_KEY_FALSE(br_mst_used);
+
+static void br_mst_vlan_set_state(struct net_bridge_port *p, struct
net_bridge_vlan *v,
+				  u8 state)
+{
+	struct net_bridge_vlan_group *vg = nbp_vlan_group(p);
+
+	if (v->state == state)
+		return;
+
+	br_vlan_set_state(v, state);
+
+	if (v->vid == vg->pvid)
+		br_vlan_set_pvid_state(vg, state);
+}
+
+int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
+		     struct netlink_ext_ack *extack)
+{
+	struct net_bridge_vlan_group *vg;
+	struct net_bridge_vlan *v;
+
+	vg = nbp_vlan_group(p);
+	if (!vg)
+		return 0;
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		if (v->brvlan->msti != msti)
+			continue;
+
+		br_mst_vlan_set_state(p, v, state);
+	}
+
+	return 0;
+}
+
+void br_mst_vlan_init_state(struct net_bridge_vlan *v)
+{
+	/* VLANs always start out in MSTI 0 (CST) */
+	v->msti = 0;
+
+	if (br_vlan_is_master(v))
+		v->state = BR_STATE_FORWARDING;
+	else
+		v->state = v->port->state;
+}
+
+int br_mst_set_enabled(struct net_bridge *br, bool on,
+		       struct netlink_ext_ack *extack)
+{
+	struct net_bridge_vlan_group *vg;
+	struct net_bridge_port *p;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		vg = nbp_vlan_group(p);
+
+		if (!vg->num_vlans)
+			continue;
+
+		NL_SET_ERR_MSG(extack,
+			       "MST mode can't be changed while VLANs exist");
+		return -EBUSY;
+	}
+
+	if (br_opt_get(br, BROPT_MST_ENABLED) == on)
+		return 0;
+
+	if (on)
+		static_branch_enable(&br_mst_used);
+	else
+		static_branch_disable(&br_mst_used);
+
+	br_opt_toggle(br, BROPT_MST_ENABLED, on);
+	return 0;
+}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 48bc61ebc211..c2190c8841fb 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -178,6 +178,7 @@ enum {
  * @br_mcast_ctx: if MASTER flag set, this is the global vlan multicast context
  * @port_mcast_ctx: if MASTER flag unset, this is the per-port/vlan multicast
  *                  context
+ * @msti: if MASTER flag set, this holds the VLANs MST instance
  * @vlist: sorted list of VLAN entries
  * @rcu: used for entry destruction
  *
@@ -210,6 +211,8 @@ struct net_bridge_vlan {
 		struct net_bridge_mcast_port	port_mcast_ctx;
 	};
 
+	u16				msti;
+
 	struct list_head		vlist;
 
 	struct rcu_head			rcu;
@@ -445,6 +448,7 @@ enum net_bridge_opts {
 	BROPT_NO_LL_LEARN,
 	BROPT_VLAN_BRIDGE_BINDING,
 	BROPT_MCAST_VLAN_SNOOPING_ENABLED,
+	BROPT_MST_ENABLED,
 };
 
 struct net_bridge {
@@ -1765,6 +1769,39 @@ static inline bool br_vlan_state_allowed(u8 state, bool
learn_allow)
 }
 #endif
 
+/* br_mst.c */
+#ifdef CONFIG_BRIDGE_VLAN_FILTERING
+DECLARE_STATIC_KEY_FALSE(br_mst_used);
+static inline bool br_mst_is_enabled(struct net_bridge *br)
+{
+	return static_branch_unlikely(&br_mst_used) &&
+		br_opt_get(br, BROPT_MST_ENABLED);
+}
+
+int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
+		     struct netlink_ext_ack *extack);
+void br_mst_vlan_init_state(struct net_bridge_vlan *v);
+int br_mst_set_enabled(struct net_bridge *br, bool on,
+		       struct netlink_ext_ack *extack);
+#else
+static inline bool br_mst_is_enabled(struct net_bridge *br)
+{
+	return false;
+}
+
+static inline int br_mst_set_state(struct net_bridge_port *p, u16 msti,
+				   u8 state, struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int br_mst_set_enabled(struct net_bridge *br, bool on,
+				     struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
 struct nf_br_ops {
 	int (*br_dev_xmit_hook)(struct sk_buff *skb);
 };
diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index 1d80f34a139c..7d27b2e6038f 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -43,6 +43,12 @@ void br_set_state(struct net_bridge_port *p, unsigned int
state)
 		return;
 
 	p->state = state;
+	if (br_opt_get(p->br, BROPT_MST_ENABLED)) {
+		err = br_mst_set_state(p, 0, state, NULL);
+		if (err)
+			br_warn(p->br, "error setting MST state on port %u(%s)\n",
+				p->port_no, netdev_name(p->dev));
+	}
 	err = switchdev_port_attr_set(p->dev, &attr, NULL);
 	if (err && err != -EOPNOTSUPP)
 		br_warn(p->br, "error setting offload STP state on port
%u(%s)\n",
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 7557e90b60e1..0f5e75ccac79 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -226,6 +226,24 @@ static void nbp_vlan_rcu_free(struct rcu_head *rcu)
 	kfree(v);
 }
 
+static void br_vlan_init_state(struct net_bridge_vlan *v)
+{
+	struct net_bridge *br;
+
+	if (br_vlan_is_master(v))
+		br = v->br;
+	else
+		br = v->port->br;
+
+	if (br_opt_get(br, BROPT_MST_ENABLED)) {
+		br_mst_vlan_init_state(v);
+		return;
+	}
+
+	v->state = BR_STATE_FORWARDING;
+	v->msti = 0;
+}
+
 /* This is the shared VLAN add function which works for both ports and bridge
  * devices. There are four possible calls to this function in terms of the
  * vlan entry type:
@@ -322,7 +340,7 @@ static int __vlan_add(struct net_bridge_vlan *v, u16 flags,
 	}
 
 	/* set the state before publishing */
-	v->state = BR_STATE_FORWARDING;
+	br_vlan_init_state(v);
 
 	err = rhashtable_lookup_insert_fast(&vg->vlan_hash, &v->vnode,
 					    br_vlan_rht_params);
diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c
index a6382973b3e7..09112b56e79c 100644
--- a/net/bridge/br_vlan_options.c
+++ b/net/bridge/br_vlan_options.c
@@ -99,6 +99,11 @@ static int br_vlan_modify_state(struct net_bridge_vlan_group
*vg,
 		return -EBUSY;
 	}
 
+	if (br_opt_get(br, BROPT_MST_ENABLED)) {
+		NL_SET_ERR_MSG_MOD(extack, "Can't modify vlan state directly when
MST is enabled");
+		return -EBUSY;
+	}
+
 	if (v->state == state)
 		return 0;
 
-- 
2.25.1

Allow a VLAN to move out of the CST (MSTI 0), to an independent tree.

The user manages the VID to MSTI mappings via a global VLAN
setting. The proposed iproute2 interface would be:

    bridge vlan global set dev br0 vid <VID> msti <MSTI>

Changing the state in non-zero MSTIs is still not supported, but will
be addressed in upcoming changes.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
Acked-by: Nikolay Aleksandrov <razor at blackwall.org>
---
 include/uapi/linux/if_bridge.h |  1 +
 net/bridge/br_mst.c            | 42 ++++++++++++++++++++++++++++++++++
 net/bridge/br_private.h        |  1 +
 net/bridge/br_vlan_options.c   | 15 ++++++++++++
 4 files changed, 59 insertions(+)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 30a242195ced..f60244b747ae 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -564,6 +564,7 @@ enum {
 	BRIDGE_VLANDB_GOPTS_MCAST_QUERIER,
 	BRIDGE_VLANDB_GOPTS_MCAST_ROUTER_PORTS,
 	BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE,
+	BRIDGE_VLANDB_GOPTS_MSTI,
 	__BRIDGE_VLANDB_GOPTS_MAX
 };
 #define BRIDGE_VLANDB_GOPTS_MAX (__BRIDGE_VLANDB_GOPTS_MAX - 1)
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 0f9f596f86bc..d7a7b5d7ddb3 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -46,6 +46,48 @@ int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8
state,
 	return 0;
 }
 
+static void br_mst_vlan_sync_state(struct net_bridge_vlan *pv, u16 msti)
+{
+	struct net_bridge_vlan_group *vg = nbp_vlan_group(pv->port);
+	struct net_bridge_vlan *v;
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		/* If this port already has a defined state in this
+		 * MSTI (through some other VLAN membership), inherit
+		 * it.
+		 */
+		if (v != pv && v->brvlan->msti == msti) {
+			br_mst_vlan_set_state(pv->port, pv, v->state);
+			return;
+		}
+	}
+
+	/* Otherwise, start out in a new MSTI with all ports disabled. */
+	return br_mst_vlan_set_state(pv->port, pv, BR_STATE_DISABLED);
+}
+
+int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)
+{
+	struct net_bridge_vlan_group *vg;
+	struct net_bridge_vlan *pv;
+	struct net_bridge_port *p;
+
+	if (mv->msti == msti)
+		return 0;
+
+	mv->msti = msti;
+
+	list_for_each_entry(p, &mv->br->port_list, list) {
+		vg = nbp_vlan_group(p);
+
+		pv = br_vlan_find(vg, mv->vid);
+		if (pv)
+			br_mst_vlan_sync_state(pv, msti);
+	}
+
+	return 0;
+}
+
 void br_mst_vlan_init_state(struct net_bridge_vlan *v)
 {
 	/* VLANs always start out in MSTI 0 (CST) */
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index c2190c8841fb..3978e1d9ffb5 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -1780,6 +1780,7 @@ static inline bool br_mst_is_enabled(struct net_bridge
*br)
 
 int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
 		     struct netlink_ext_ack *extack);
+int br_mst_vlan_set_msti(struct net_bridge_vlan *v, u16 msti);
 void br_mst_vlan_init_state(struct net_bridge_vlan *v);
 int br_mst_set_enabled(struct net_bridge *br, bool on,
 		       struct netlink_ext_ack *extack);
diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c
index 09112b56e79c..a2724d03278c 100644
--- a/net/bridge/br_vlan_options.c
+++ b/net/bridge/br_vlan_options.c
@@ -296,6 +296,7 @@ bool br_vlan_global_opts_can_enter_range(const struct
net_bridge_vlan *v_curr,
 					 const struct net_bridge_vlan *r_end)
 {
 	return v_curr->vid - r_end->vid == 1 &&
+		v_curr->msti == r_end->msti &&
 	       ((v_curr->priv_flags ^ r_end->priv_flags) &
 		BR_VLFLAG_GLOBAL_MCAST_ENABLED) == 0 &&
 		br_multicast_ctx_options_equal(&v_curr->br_mcast_ctx,
@@ -384,6 +385,9 @@ bool br_vlan_global_opts_fill(struct sk_buff *skb, u16 vid,
u16 vid_range,
 #endif
 #endif
 
+	if (nla_put_u16(skb, BRIDGE_VLANDB_GOPTS_MSTI, v_opts->msti))
+		goto out_err;
+
 	nla_nest_end(skb, nest);
 
 	return true;
@@ -415,6 +419,7 @@ static size_t rtnl_vlan_global_opts_nlmsg_size(const struct
net_bridge_vlan *v)
 		+ nla_total_size(0) /* BRIDGE_VLANDB_GOPTS_MCAST_ROUTER_PORTS */
 		+ br_rports_size(&v->br_mcast_ctx) /*
BRIDGE_VLANDB_GOPTS_MCAST_ROUTER_PORTS */
 #endif
+		+ nla_total_size(sizeof(u16)) /* BRIDGE_VLANDB_GOPTS_MSTI */
 		+ nla_total_size(sizeof(u16)); /* BRIDGE_VLANDB_GOPTS_RANGE */
 }
 
@@ -564,6 +569,15 @@ static int br_vlan_process_global_one_opts(const struct
net_bridge *br,
 	}
 #endif
 #endif
+	if (tb[BRIDGE_VLANDB_GOPTS_MSTI]) {
+		u16 msti;
+
+		msti = nla_get_u16(tb[BRIDGE_VLANDB_GOPTS_MSTI]);
+		err = br_mst_vlan_set_msti(v, msti);
+		if (err)
+			return err;
+		*changed = true;
+	}
 
 	return 0;
 }
@@ -583,6 +597,7 @@ static const struct nla_policy
br_vlan_db_gpol[BRIDGE_VLANDB_GOPTS_MAX + 1] = {
 	[BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_INTVL]	= { .type = NLA_U64 },
 	[BRIDGE_VLANDB_GOPTS_MCAST_STARTUP_QUERY_INTVL]	= { .type = NLA_U64 },
 	[BRIDGE_VLANDB_GOPTS_MCAST_QUERY_RESPONSE_INTVL] = { .type = NLA_U64 },
+	[BRIDGE_VLANDB_GOPTS_MSTI] = NLA_POLICY_MAX(NLA_U16, VLAN_N_VID - 1),
 };
 
 int br_vlan_rtm_process_global_options(struct net_device *dev,
-- 
2.25.1

Make it possible to change the port state in a given MSTI by extending
the bridge port netlink interface (RTM_SETLINK on PF_BRIDGE).The
proposed iproute2 interface would be:

    bridge mst set dev <PORT> msti <MSTI> state <STATE>

Current states in all applicable MSTIs can also be dumped via a
corresponding RTM_GETLINK. The proposed iproute interface looks like
this:

$ bridge mst
port              msti
vb1               0
		    state forwarding
		  100
		    state disabled
vb2               0
		    state forwarding
		  100
		    state forwarding

The preexisting per-VLAN states are still valid in the MST
mode (although they are read-only), and can be queried as usual if one
is interested in knowing a particular VLAN's state without having to
care about the VID to MSTI mapping (in this example VLAN 20 and 30 are
bound to MSTI 100):

$ bridge -d vlan
port              vlan-id
vb1               10
		    state forwarding mcast_router 1
		  20
		    state disabled mcast_router 1
		  30
		    state disabled mcast_router 1
		  40
		    state forwarding mcast_router 1
vb2               10
		    state forwarding mcast_router 1
		  20
		    state forwarding mcast_router 1
		  30
		    state forwarding mcast_router 1
		  40
		    state forwarding mcast_router 1

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/uapi/linux/if_bridge.h |  16 +++++
 include/uapi/linux/rtnetlink.h |   1 +
 net/bridge/br_mst.c            | 126 +++++++++++++++++++++++++++++++++
 net/bridge/br_netlink.c        |  44 +++++++++++-
 net/bridge/br_private.h        |  23 ++++++
 5 files changed, 209 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index f60244b747ae..a86a7e7b811f 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -122,6 +122,7 @@ enum {
 	IFLA_BRIDGE_VLAN_TUNNEL_INFO,
 	IFLA_BRIDGE_MRP,
 	IFLA_BRIDGE_CFM,
+	IFLA_BRIDGE_MST,
 	__IFLA_BRIDGE_MAX,
 };
 #define IFLA_BRIDGE_MAX (__IFLA_BRIDGE_MAX - 1)
@@ -453,6 +454,21 @@ enum {
 
 #define IFLA_BRIDGE_CFM_CC_PEER_STATUS_MAX
(__IFLA_BRIDGE_CFM_CC_PEER_STATUS_MAX - 1)
 
+enum {
+	IFLA_BRIDGE_MST_UNSPEC,
+	IFLA_BRIDGE_MST_ENTRY,
+	__IFLA_BRIDGE_MST_MAX,
+};
+#define IFLA_BRIDGE_MST_MAX (__IFLA_BRIDGE_MST_MAX - 1)
+
+enum {
+	IFLA_BRIDGE_MST_ENTRY_UNSPEC,
+	IFLA_BRIDGE_MST_ENTRY_MSTI,
+	IFLA_BRIDGE_MST_ENTRY_STATE,
+	__IFLA_BRIDGE_MST_ENTRY_MAX,
+};
+#define IFLA_BRIDGE_MST_ENTRY_MAX (__IFLA_BRIDGE_MST_ENTRY_MAX - 1)
+
 struct bridge_stp_xstats {
 	__u64 transition_blk;
 	__u64 transition_fwd;
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 51530aade46e..83849a37db5b 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -817,6 +817,7 @@ enum {
 #define RTEXT_FILTER_MRP	(1 << 4)
 #define RTEXT_FILTER_CFM_CONFIG	(1 << 5)
 #define RTEXT_FILTER_CFM_STATUS	(1 << 6)
+#define RTEXT_FILTER_MST	(1 << 7)
 
 /* End of information exported to user level */
 
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index d7a7b5d7ddb3..5c1831c73fc2 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -127,3 +127,129 @@ int br_mst_set_enabled(struct net_bridge *br, bool on,
 	br_opt_toggle(br, BROPT_MST_ENABLED, on);
 	return 0;
 }
+
+size_t br_mst_info_size(const struct net_bridge_vlan_group *vg)
+{
+	DECLARE_BITMAP(seen, VLAN_N_VID) = { 0 };
+	const struct net_bridge_vlan *v;
+	size_t sz;
+
+	/* IFLA_BRIDGE_MST */
+	sz = nla_total_size(0);
+
+	list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
+		if (test_bit(v->brvlan->msti, seen))
+			continue;
+
+		/* IFLA_BRIDGE_MST_ENTRY */
+		sz += nla_total_size(0) +
+			/* IFLA_BRIDGE_MST_ENTRY_MSTI */
+			nla_total_size(sizeof(u16)) +
+			/* IFLA_BRIDGE_MST_ENTRY_STATE */
+			nla_total_size(sizeof(u8));
+
+		__set_bit(v->brvlan->msti, seen);
+	}
+
+	return sz;
+}
+
+int br_mst_fill_info(struct sk_buff *skb,
+		     const struct net_bridge_vlan_group *vg)
+{
+	DECLARE_BITMAP(seen, VLAN_N_VID) = { 0 };
+	const struct net_bridge_vlan *v;
+	struct nlattr *nest;
+	int err = 0;
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		if (test_bit(v->brvlan->msti, seen))
+			continue;
+
+		nest = nla_nest_start_noflag(skb, IFLA_BRIDGE_MST_ENTRY);
+		if (!nest ||
+		    nla_put_u16(skb, IFLA_BRIDGE_MST_ENTRY_MSTI, v->brvlan->msti) ||
+		    nla_put_u8(skb, IFLA_BRIDGE_MST_ENTRY_STATE, v->state)) {
+			err = -EMSGSIZE;
+			break;
+		}
+		nla_nest_end(skb, nest);
+
+		__set_bit(v->brvlan->msti, seen);
+	}
+
+	return err;
+}
+
+static const struct nla_policy br_mst_nl_policy[IFLA_BRIDGE_MST_ENTRY_MAX + 1]
= {
+	[IFLA_BRIDGE_MST_ENTRY_MSTI] = NLA_POLICY_RANGE(NLA_U16,
+						   1, /* 0 reserved for CST */
+						   VLAN_N_VID - 1),
+	[IFLA_BRIDGE_MST_ENTRY_STATE] = NLA_POLICY_RANGE(NLA_U8,
+						    BR_STATE_DISABLED,
+						    BR_STATE_BLOCKING),
+};
+
+static int br_mst_process_one(struct net_bridge_port *p,
+			      const struct nlattr *attr,
+			      struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[IFLA_BRIDGE_MST_ENTRY_MAX + 1];
+	u16 msti;
+	u8 state;
+	int err;
+
+	err = nla_parse_nested(tb, IFLA_BRIDGE_MST_ENTRY_MAX, attr,
+			       br_mst_nl_policy, extack);
+	if (err)
+		return err;
+
+	if (!tb[IFLA_BRIDGE_MST_ENTRY_MSTI]) {
+		NL_SET_ERR_MSG_MOD(extack, "MSTI not specified");
+		return -EINVAL;
+	}
+
+	if (!tb[IFLA_BRIDGE_MST_ENTRY_STATE]) {
+		NL_SET_ERR_MSG_MOD(extack, "State not specified");
+		return -EINVAL;
+	}
+
+	msti = nla_get_u16(tb[IFLA_BRIDGE_MST_ENTRY_MSTI]);
+	state = nla_get_u8(tb[IFLA_BRIDGE_MST_ENTRY_STATE]);
+
+	return br_mst_set_state(p, msti, state, extack);
+}
+
+int br_mst_process(struct net_bridge_port *p, const struct nlattr *mst_attr,
+		   struct netlink_ext_ack *extack)
+{
+	struct nlattr *attr;
+	int err, msts = 0;
+	int rem;
+
+	if (!br_opt_get(p->br, BROPT_MST_ENABLED)) {
+		NL_SET_ERR_MSG_MOD(extack, "Can't modify MST state when MST is
disabled");
+		return -EBUSY;
+	}
+
+	nla_for_each_nested(attr, mst_attr, rem) {
+		switch (nla_type(attr)) {
+		case IFLA_BRIDGE_MST_ENTRY:
+			err = br_mst_process_one(p, attr, extack);
+			break;
+		default:
+			continue;
+		}
+
+		msts++;
+		if (err)
+			break;
+	}
+
+	if (!msts) {
+		NL_SET_ERR_MSG_MOD(extack, "Found no MST entries to process");
+		err = -EINVAL;
+	}
+
+	return err;
+}
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 7d4432ca9a20..a8d90fa8621e 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -119,6 +119,9 @@ static size_t br_get_link_af_size_filtered(const struct
net_device *dev,
 	/* Each VLAN is returned in bridge_vlan_info along with flags */
 	vinfo_sz += num_vlan_infos * nla_total_size(sizeof(struct bridge_vlan_info));
 
+	if (filter_mask & RTEXT_FILTER_MST)
+		vinfo_sz += br_mst_info_size(vg);
+
 	if (!(filter_mask & RTEXT_FILTER_CFM_STATUS))
 		return vinfo_sz;
 
@@ -485,7 +488,8 @@ static int br_fill_ifinfo(struct sk_buff *skb,
 			   RTEXT_FILTER_BRVLAN_COMPRESSED |
 			   RTEXT_FILTER_MRP |
 			   RTEXT_FILTER_CFM_CONFIG |
-			   RTEXT_FILTER_CFM_STATUS)) {
+			   RTEXT_FILTER_CFM_STATUS |
+			   RTEXT_FILTER_MST)) {
 		af = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
 		if (!af)
 			goto nla_put_failure;
@@ -564,7 +568,28 @@ static int br_fill_ifinfo(struct sk_buff *skb,
 		nla_nest_end(skb, cfm_nest);
 	}
 
+	if ((filter_mask & RTEXT_FILTER_MST) &&
+	    br_opt_get(br, BROPT_MST_ENABLED) && port) {
+		const struct net_bridge_vlan_group *vg = nbp_vlan_group(port);
+		struct nlattr *mst_nest;
+		int err;
+
+		if (!vg || !vg->num_vlans)
+			goto done;
+
+		mst_nest = nla_nest_start(skb, IFLA_BRIDGE_MST);
+		if (!mst_nest)
+			goto nla_put_failure;
+
+		err = br_mst_fill_info(skb, vg);
+		if (err)
+			goto nla_put_failure;
+
+		nla_nest_end(skb, mst_nest);
+	}
+
 done:
+
 	if (af)
 		nla_nest_end(skb, af);
 	nlmsg_end(skb, nlh);
@@ -803,6 +828,23 @@ static int br_afspec(struct net_bridge *br,
 			if (err)
 				return err;
 			break;
+		case IFLA_BRIDGE_MST:
+			if (!p) {
+				NL_SET_ERR_MSG(extack,
+					       "MST states can only be set on bridge ports");
+				return -EINVAL;
+			}
+
+			if (cmd != RTM_SETLINK) {
+				NL_SET_ERR_MSG(extack,
+					       "MST states can only be set through RTM_SETLINK");
+				return -EINVAL;
+			}
+
+			err = br_mst_process(p, attr, extack);
+			if (err)
+				return err;
+			break;
 		}
 	}
 
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 3978e1d9ffb5..18ccc3d5d296 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -1784,6 +1784,11 @@ int br_mst_vlan_set_msti(struct net_bridge_vlan *v, u16
msti);
 void br_mst_vlan_init_state(struct net_bridge_vlan *v);
 int br_mst_set_enabled(struct net_bridge *br, bool on,
 		       struct netlink_ext_ack *extack);
+size_t br_mst_info_size(const struct net_bridge_vlan_group *vg);
+int br_mst_fill_info(struct sk_buff *skb,
+		     const struct net_bridge_vlan_group *vg);
+int br_mst_process(struct net_bridge_port *p, const struct nlattr *mst_attr,
+		   struct netlink_ext_ack *extack);
 #else
 static inline bool br_mst_is_enabled(struct net_bridge *br)
 {
@@ -1801,6 +1806,24 @@ static inline int br_mst_set_enabled(struct net_bridge
*br, bool on,
 {
 	return -EOPNOTSUPP;
 }
+
+static inline size_t br_mst_info_size(const struct net_bridge_vlan_group *vg)
+{
+	return 0;
+}
+
+static inline int br_mst_fill_info(struct sk_buff *skb,
+				   const struct net_bridge_vlan_group *vg)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int br_mst_process(struct net_bridge_port *p,
+				 const struct nlattr *mst_attr,
+				 struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 struct nf_br_ops {
-- 
2.25.1

Trigger a switchdev event whenever the bridge's MST mode is
enabled/disabled. This allows constituent ports to either perform any
required hardware config, or refuse the change if it not supported.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/net/switchdev.h |  2 ++
 net/bridge/br_mst.c     | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 3e424d40fae3..85dd004dc9ad 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -27,6 +27,7 @@ enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL,
 	SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED,
 	SWITCHDEV_ATTR_ID_BRIDGE_MROUTER,
+	SWITCHDEV_ATTR_ID_BRIDGE_MST,
 	SWITCHDEV_ATTR_ID_MRP_PORT_ROLE,
 };
 
@@ -48,6 +49,7 @@ struct switchdev_attr {
 		clock_t ageing_time;			/* BRIDGE_AGEING_TIME */
 		bool vlan_filtering;			/* BRIDGE_VLAN_FILTERING */
 		u16 vlan_protocol;			/* BRIDGE_VLAN_PROTOCOL */
+		bool mst;				/* BRIDGE_MST */
 		bool mc_disabled;			/* MC_DISABLED */
 		u8 mrp_port_role;			/* MRP_PORT_ROLE */
 	} u;
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 5c1831c73fc2..43ca6b97c5c3 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/kernel.h>
+#include <net/switchdev.h>
 
 #include "br_private.h"
 
@@ -102,8 +103,14 @@ void br_mst_vlan_init_state(struct net_bridge_vlan *v)
 int br_mst_set_enabled(struct net_bridge *br, bool on,
 		       struct netlink_ext_ack *extack)
 {
+	struct switchdev_attr attr = {
+		.id = SWITCHDEV_ATTR_ID_BRIDGE_MST,
+		.orig_dev = br->dev,
+		.u.mst = on,
+	};
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_port *p;
+	int err;
 
 	list_for_each_entry(p, &br->port_list, list) {
 		vg = nbp_vlan_group(p);
@@ -119,6 +126,10 @@ int br_mst_set_enabled(struct net_bridge *br, bool on,
 	if (br_opt_get(br, BROPT_MST_ENABLED) == on)
 		return 0;
 
+	err = switchdev_port_attr_set(br->dev, &attr, extack);
+	if (err && err != -EOPNOTSUPP)
+		return err;
+
 	if (on)
 		static_branch_enable(&br_mst_used);
 	else
-- 
2.25.1

Whenever a VLAN moves to a new MSTI, send a switchdev notification so
that switchdevs can track a bridge's VID to MSTI mappings.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/net/switchdev.h   |  7 ++++++
 net/bridge/br_mst.c       | 13 +++++++++++
 net/bridge/br_switchdev.c | 46 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 85dd004dc9ad..53dfa0f7cf5b 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -29,6 +29,7 @@ enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_BRIDGE_MROUTER,
 	SWITCHDEV_ATTR_ID_BRIDGE_MST,
 	SWITCHDEV_ATTR_ID_MRP_PORT_ROLE,
+	SWITCHDEV_ATTR_ID_VLAN_MSTI,
 };
 
 struct switchdev_brport_flags {
@@ -36,6 +37,11 @@ struct switchdev_brport_flags {
 	unsigned long mask;
 };
 
+struct switchdev_vlan_msti {
+	u16 vid;
+	u16 msti;
+};
+
 struct switchdev_attr {
 	struct net_device *orig_dev;
 	enum switchdev_attr_id id;
@@ -52,6 +58,7 @@ struct switchdev_attr {
 		bool mst;				/* BRIDGE_MST */
 		bool mc_disabled;			/* MC_DISABLED */
 		u8 mrp_port_role;			/* MRP_PORT_ROLE */
+		struct switchdev_vlan_msti vlan_msti;	/* VLAN_MSTI */
 	} u;
 };
 
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 43ca6b97c5c3..29266174e6b4 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -69,13 +69,26 @@ static void br_mst_vlan_sync_state(struct net_bridge_vlan
*pv, u16 msti)
 
 int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)
 {
+	struct switchdev_attr attr = {
+		.id = SWITCHDEV_ATTR_ID_VLAN_MSTI,
+		.orig_dev = mv->br->dev,
+		.u.vlan_msti = {
+			.vid = mv->vid,
+			.msti = msti,
+		},
+	};
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_vlan *pv;
 	struct net_bridge_port *p;
+	int err;
 
 	if (mv->msti == msti)
 		return 0;
 
+	err = switchdev_port_attr_set(mv->br->dev, &attr, NULL);
+	if (err && err != -EOPNOTSUPP)
+		return err;
+
 	mv->msti = msti;
 
 	list_for_each_entry(p, &mv->br->port_list, list) {
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index 6f6a70121a5e..8cc44c367231 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -331,6 +331,46 @@ br_switchdev_fdb_replay(const struct net_device *br_dev,
const void *ctx,
 	return err;
 }
 
+static int br_switchdev_vlan_attr_replay(struct net_device *br_dev,
+					 const void *ctx,
+					 struct notifier_block *nb,
+					 struct netlink_ext_ack *extack)
+{
+	struct switchdev_notifier_port_attr_info attr_info = {
+		.info = {
+			.dev = br_dev,
+			.extack = extack,
+			.ctx = ctx,
+		},
+	};
+	struct net_bridge *br = netdev_priv(br_dev);
+	struct net_bridge_vlan_group *vg;
+	struct switchdev_attr attr;
+	struct net_bridge_vlan *v;
+	int err;
+
+	attr_info.attr = &attr;
+	attr.orig_dev = br_dev;
+
+	vg = br_vlan_group(br);
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		if (v->msti) {
+			attr.id = SWITCHDEV_ATTR_ID_VLAN_MSTI;
+			attr.u.vlan_msti.vid = v->vid;
+			attr.u.vlan_msti.msti = v->msti;
+
+			err = nb->notifier_call(nb, SWITCHDEV_PORT_ATTR_SET,
+						&attr_info);
+			err = notifier_to_errno(err);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
 static int
 br_switchdev_vlan_replay_one(struct notifier_block *nb,
 			     struct net_device *dev,
@@ -425,6 +465,12 @@ static int br_switchdev_vlan_replay(struct net_device
*br_dev,
 			return err;
 	}
 
+	if (adding) {
+		err = br_switchdev_vlan_attr_replay(br_dev, ctx, nb, extack);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
-- 
2.25.1

Generate a switchdev notification whenever an MST state changes. This
notification is keyed by the VLANs MSTI rather than the VID, since
multiple VLANs may share the same MST instance.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/net/switchdev.h |  7 +++++++
 net/bridge/br_mst.c     | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index 53dfa0f7cf5b..aa0171d5786d 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -19,6 +19,7 @@
 enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_UNDEFINED,
 	SWITCHDEV_ATTR_ID_PORT_STP_STATE,
+	SWITCHDEV_ATTR_ID_PORT_MST_STATE,
 	SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS,
 	SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS,
 	SWITCHDEV_ATTR_ID_PORT_MROUTER,
@@ -32,6 +33,11 @@ enum switchdev_attr_id {
 	SWITCHDEV_ATTR_ID_VLAN_MSTI,
 };
 
+struct switchdev_mst_state {
+	u16 msti;
+	u8 state;
+};
+
 struct switchdev_brport_flags {
 	unsigned long val;
 	unsigned long mask;
@@ -50,6 +56,7 @@ struct switchdev_attr {
 	void (*complete)(struct net_device *dev, int err, void *priv);
 	union {
 		u8 stp_state;				/* PORT_STP_STATE */
+		struct switchdev_mst_state mst_state;	/* PORT_MST_STATE */
 		struct switchdev_brport_flags brport_flags; /* PORT_BRIDGE_FLAGS */
 		bool mrouter;				/* PORT_MROUTER */
 		clock_t ageing_time;			/* BRIDGE_AGEING_TIME */
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 29266174e6b4..00935a19afcc 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -30,13 +30,31 @@ static void br_mst_vlan_set_state(struct net_bridge_port *p,
struct net_bridge_v
 int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
 		     struct netlink_ext_ack *extack)
 {
+	struct switchdev_attr attr = {
+		.id = SWITCHDEV_ATTR_ID_PORT_MST_STATE,
+		.orig_dev = p->dev,
+		.u.mst_state = {
+			.msti = msti,
+			.state = state,
+		},
+	};
 	struct net_bridge_vlan_group *vg;
 	struct net_bridge_vlan *v;
+	int err;
 
 	vg = nbp_vlan_group(p);
 	if (!vg)
 		return 0;
 
+	/* MSTI 0 (CST) state changes are notified via the regular
+	 * SWITCHDEV_ATTR_ID_PORT_STP_STATE.
+	 */
+	if (msti) {
+		err = switchdev_port_attr_set(p->dev, &attr, extack);
+		if (err && err != -EOPNOTSUPP)
+			return err;
+	}
+
 	list_for_each_entry(v, &vg->vlan_list, vlist) {
 		if (v->brvlan->msti != msti)
 			continue;
-- 
2.25.1

br_mst_get_info answers the question: "On this bridge, which VIDs are
mapped to the given MSTI?"

This is useful in switchdev drivers, which might have to fan-out
operations, relating to an MSTI, per VLAN.

An example: When a port's MST state changes from forwarding to
blocking, a driver may choose to flush the dynamic FDB entries on that
port to get faster reconvergence of the network, but this should only
be done in the VLANs that are managed by the MSTI in question.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/linux/if_bridge.h |  7 +++++++
 net/bridge/br_mst.c       | 26 ++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 3aae023a9353..1cf0cc46d90d 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -119,6 +119,7 @@ int br_vlan_get_info(const struct net_device *dev, u16 vid,
 		     struct bridge_vlan_info *p_vinfo);
 int br_vlan_get_info_rcu(const struct net_device *dev, u16 vid,
 			 struct bridge_vlan_info *p_vinfo);
+int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long
*vids);
 #else
 static inline bool br_vlan_enabled(const struct net_device *dev)
 {
@@ -151,6 +152,12 @@ static inline int br_vlan_get_info_rcu(const struct
net_device *dev, u16 vid,
 {
 	return -EINVAL;
 }
+
+static inline int br_mst_get_info(const struct net_device *dev, u16 msti,
+				  unsigned long *vids)
+{
+	return -EINVAL;
+}
 #endif
 
 #if IS_ENABLED(CONFIG_BRIDGE)
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 00935a19afcc..00b36e629224 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -13,6 +13,32 @@
 
 DEFINE_STATIC_KEY_FALSE(br_mst_used);
 
+int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long
*vids)
+{
+	const struct net_bridge_vlan_group *vg;
+	const struct net_bridge_vlan *v;
+	const struct net_bridge *br;
+
+	ASSERT_RTNL();
+
+	if (!netif_is_bridge_master(dev))
+		return -EINVAL;
+
+	br = netdev_priv(dev);
+	if (!br_opt_get(br, BROPT_MST_ENABLED))
+		return -EINVAL;
+
+	vg = br_vlan_group(br);
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		if (v->msti == msti)
+			__set_bit(v->vid, vids);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(br_mst_get_info);
+
 static void br_mst_vlan_set_state(struct net_bridge_port *p, struct
net_bridge_vlan *v,
 				  u8 state)
 {
-- 
2.25.1

This is useful for switchdev drivers that might want to refuse to join
a bridge where MST is enabled, if the hardware can't support it.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/linux/if_bridge.h | 6 ++++++
 net/bridge/br_mst.c       | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 1cf0cc46d90d..4efd5540279a 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -119,6 +119,7 @@ int br_vlan_get_info(const struct net_device *dev, u16 vid,
 		     struct bridge_vlan_info *p_vinfo);
 int br_vlan_get_info_rcu(const struct net_device *dev, u16 vid,
 			 struct bridge_vlan_info *p_vinfo);
+bool br_mst_enabled(const struct net_device *dev);
 int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long
*vids);
 #else
 static inline bool br_vlan_enabled(const struct net_device *dev)
@@ -153,6 +154,11 @@ static inline int br_vlan_get_info_rcu(const struct
net_device *dev, u16 vid,
 	return -EINVAL;
 }
 
+static inline bool br_mst_enabled(const struct net_device *dev)
+{
+	return false;
+}
+
 static inline int br_mst_get_info(const struct net_device *dev, u16 msti,
 				  unsigned long *vids)
 {
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 00b36e629224..830a5746479f 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -13,6 +13,15 @@
 
 DEFINE_STATIC_KEY_FALSE(br_mst_used);
 
+bool br_mst_enabled(const struct net_device *dev)
+{
+	if (!netif_is_bridge_master(dev))
+		return false;
+
+	return br_opt_get(netdev_priv(dev), BROPT_MST_ENABLED);
+}
+EXPORT_SYMBOL_GPL(br_mst_enabled);
+
 int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long
*vids)
 {
 	const struct net_bridge_vlan_group *vg;
-- 
2.25.1

This is useful for switchdev drivers who are offloading MST states
into hardware. As an example, a driver may wish to flush the FDB for a
port when it transitions from forwarding to blocking - which means
that the previous state must be discoverable.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/linux/if_bridge.h |  6 ++++++
 net/bridge/br_mst.c       | 25 +++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 4efd5540279a..d62ef428e3aa 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -121,6 +121,7 @@ int br_vlan_get_info_rcu(const struct net_device *dev, u16
vid,
 			 struct bridge_vlan_info *p_vinfo);
 bool br_mst_enabled(const struct net_device *dev);
 int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long
*vids);
+int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state);
 #else
 static inline bool br_vlan_enabled(const struct net_device *dev)
 {
@@ -164,6 +165,11 @@ static inline int br_mst_get_info(const struct net_device
*dev, u16 msti,
 {
 	return -EINVAL;
 }
+static inline int br_mst_get_state(const struct net_device *dev, u16 msti,
+				   u8 *state)
+{
+	return -EINVAL;
+}
 #endif
 
 #if IS_ENABLED(CONFIG_BRIDGE)
diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 830a5746479f..ee680adcee17 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -48,6 +48,31 @@ int br_mst_get_info(const struct net_device *dev, u16 msti,
unsigned long *vids)
 }
 EXPORT_SYMBOL_GPL(br_mst_get_info);
 
+int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state)
+{
+	const struct net_bridge_port *p = NULL;
+	const struct net_bridge_vlan_group *vg;
+	const struct net_bridge_vlan *v;
+
+	ASSERT_RTNL();
+
+	p = br_port_get_check_rtnl(dev);
+	if (!p || !br_opt_get(p->br, BROPT_MST_ENABLED))
+		return -EINVAL;
+
+	vg = nbp_vlan_group(p);
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		if (v->brvlan->msti == msti) {
+			*state = v->state;
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(br_mst_get_state);
+
 static void br_mst_vlan_set_state(struct net_bridge_port *p, struct
net_bridge_vlan *v,
 				  u8 state)
 {
-- 
2.25.1

When joining a bridge where MST is enabled, we validate that the
proper offloading support is in place, otherwise we fallback to
software bridging.

When then mode is changed on a bridge in which we are members, we
refuse the change if offloading is not supported.

At the moment we only check for configurable learning, but this will
be further restricted as we support more MST related switchdev events.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 net/dsa/dsa_priv.h |  2 ++
 net/dsa/port.c     | 22 ++++++++++++++++++++++
 net/dsa/slave.c    |  6 ++++++
 3 files changed, 30 insertions(+)

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index f20bdd8ea0a8..2aba420696ef 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -234,6 +234,8 @@ int dsa_port_vlan_filtering(struct dsa_port *dp, bool
vlan_filtering,
 			    struct netlink_ext_ack *extack);
 bool dsa_port_skip_vlan_configuration(struct dsa_port *dp);
 int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock);
+int dsa_port_mst_enable(struct dsa_port *dp, bool on,
+			struct netlink_ext_ack *extack);
 int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu,
 			bool targeted_match);
 int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 58291df14cdb..02214033cec0 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -321,6 +321,11 @@ static void dsa_port_bridge_destroy(struct dsa_port *dp,
 	kfree(bridge);
 }
 
+static bool dsa_port_supports_mst(struct dsa_port *dp)
+{
+	return dsa_port_can_configure_learning(dp);
+}
+
 int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
 			 struct netlink_ext_ack *extack)
 {
@@ -334,6 +339,9 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct
net_device *br,
 	struct net_device *brport_dev;
 	int err;
 
+	if (br_mst_enabled(br) && !dsa_port_supports_mst(dp))
+		return -EOPNOTSUPP;
+
 	/* Here the interface is already bridged. Reflect the current
 	 * configuration so that drivers can program their chips accordingly.
 	 */
@@ -735,6 +743,20 @@ int dsa_port_ageing_time(struct dsa_port *dp, clock_t
ageing_clock)
 	return 0;
 }
 
+int dsa_port_mst_enable(struct dsa_port *dp, bool on,
+			struct netlink_ext_ack *extack)
+{
+	if (!on)
+		return 0;
+
+	if (!dsa_port_supports_mst(dp)) {
+		NL_SET_ERR_MSG_MOD(extack, "Hardware does not support MST");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 int dsa_port_pre_bridge_flags(const struct dsa_port *dp,
 			      struct switchdev_brport_flags flags,
 			      struct netlink_ext_ack *extack)
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index f9cecda791d5..2e8f62476ce9 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -464,6 +464,12 @@ static int dsa_slave_port_attr_set(struct net_device *dev,
const void *ctx,
 
 		ret = dsa_port_ageing_time(dp, attr->u.ageing_time);
 		break;
+	case SWITCHDEV_ATTR_ID_BRIDGE_MST:
+		if (!dsa_port_offloads_bridge_dev(dp, attr->orig_dev))
+			return -EOPNOTSUPP;
+
+		ret = dsa_port_mst_enable(dp, attr->u.mst, extack);
+		break;
 	case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
 		if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
 			return -EOPNOTSUPP;
-- 
2.25.1

Add the usual trampoline functionality from the generic DSA layer down
to the drivers for VLAN MSTI migrations.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv at gmail.com>
---
 include/net/dsa.h  |  3 +++
 net/dsa/dsa_priv.h |  2 ++
 net/dsa/port.c     | 16 +++++++++++++++-
 net/dsa/slave.c    |  6 ++++++
 4 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 9bfe984fcdbf..644fda2293a2 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -976,6 +976,9 @@ struct dsa_switch_ops {
 				 struct netlink_ext_ack *extack);
 	int	(*port_vlan_del)(struct dsa_switch *ds, int port,
 				 const struct switchdev_obj_port_vlan *vlan);
+	int	(*vlan_msti_set)(struct dsa_switch *ds, struct dsa_bridge bridge,
+				 const struct switchdev_vlan_msti *msti);
+
 	/*
 	 * Forwarding database
 	 */
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 2aba420696ef..d90b4cf0c9d2 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -236,6 +236,8 @@ bool dsa_port_skip_vlan_configuration(struct dsa_port *dp);
 int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock);
 int dsa_port_mst_enable(struct dsa_port *dp, bool on,
 			struct netlink_ext_ack *extack);
+int dsa_port_vlan_msti(struct dsa_port *dp,
+		       const struct switchdev_vlan_msti *msti);
 int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu,
 			bool targeted_match);
 int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 02214033cec0..3ac114f6fc22 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -323,7 +323,10 @@ static void dsa_port_bridge_destroy(struct dsa_port *dp,
 
 static bool dsa_port_supports_mst(struct dsa_port *dp)
 {
-	return dsa_port_can_configure_learning(dp);
+	struct dsa_switch *ds = dp->ds;
+
+	return ds->ops->vlan_msti_set &&
+		dsa_port_can_configure_learning(dp);
 }
 
 int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
@@ -800,6 +803,17 @@ int dsa_port_bridge_flags(struct dsa_port *dp,
 	return 0;
 }
 
+int dsa_port_vlan_msti(struct dsa_port *dp,
+		       const struct switchdev_vlan_msti *msti)
+{
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->vlan_msti_set)
+		return -EOPNOTSUPP;
+
+	return ds->ops->vlan_msti_set(ds, *dp->bridge, msti);
+}
+
 int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu,
 			bool targeted_match)
 {
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 2e8f62476ce9..1b3e792d0327 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -483,6 +483,12 @@ static int dsa_slave_port_attr_set(struct net_device *dev,
const void *ctx,
 
 		ret = dsa_port_bridge_flags(dp, attr->u.brport_flags, extack);
 		break;
+	case SWITCHDEV_ATTR_ID_VLAN_MSTI:
+		if (!dsa_port_offloads_bridge_dev(dp, attr->orig_dev))
+			return -EOPNOTSUPP;
+
+		ret = dsa_port_vlan_msti(dp, &attr->u.vlan_msti);
+		break;
 	default:
 		ret = -EOPNOTSUPP;
 		break;
-- 
2.25.1

Add the usual trampoline functionality from the generic DSA layer down
to the drivers for MST state changes.

When a state changes to disabled/blocking/listening, make sure to fast
age any dynamic entries in the affected VLANs (those controlled by the
MSTI in question).

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 include/net/dsa.h  |  3 ++
 net/dsa/dsa_priv.h |  3 ++
 net/dsa/port.c     | 85 +++++++++++++++++++++++++++++++++++++++++-----
 net/dsa/slave.c    |  6 ++++
 4 files changed, 89 insertions(+), 8 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 644fda2293a2..06cdefd3b9dd 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -957,7 +957,10 @@ struct dsa_switch_ops {
 				     struct dsa_bridge bridge);
 	void	(*port_stp_state_set)(struct dsa_switch *ds, int port,
 				      u8 state);
+	int	(*port_mst_state_set)(struct dsa_switch *ds, int port,
+				      const struct switchdev_mst_state *state);
 	void	(*port_fast_age)(struct dsa_switch *ds, int port);
+	int	(*port_vlan_fast_age)(struct dsa_switch *ds, int port, u16 vid);
 	int	(*port_pre_bridge_flags)(struct dsa_switch *ds, int port,
 					 struct switchdev_brport_flags flags,
 					 struct netlink_ext_ack *extack);
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index d90b4cf0c9d2..5d3f4a67dce1 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -215,6 +215,9 @@ static inline struct net_device
*dsa_master_find_slave(struct net_device *dev,
 void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
 			       const struct dsa_device_ops *tag_ops);
 int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);
+int dsa_port_set_mst_state(struct dsa_port *dp,
+			   const struct switchdev_mst_state *state,
+			   struct netlink_ext_ack *extack);
 int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy);
 int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy);
 void dsa_port_disable_rt(struct dsa_port *dp);
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 3ac114f6fc22..32d472a82241 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -30,12 +30,11 @@ static int dsa_port_notify(const struct dsa_port *dp,
unsigned long e, void *v)
 	return dsa_tree_notify(dp->ds->dst, e, v);
 }
 
-static void dsa_port_notify_bridge_fdb_flush(const struct dsa_port *dp)
+static void dsa_port_notify_bridge_fdb_flush(const struct dsa_port *dp, u16
vid)
 {
 	struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
 	struct switchdev_notifier_fdb_info info = {
-		/* flush all VLANs */
-		.vid = 0,
+		.vid = vid,
 	};
 
 	/* When the port becomes standalone it has already left the bridge.
@@ -57,7 +56,42 @@ static void dsa_port_fast_age(const struct dsa_port *dp)
 
 	ds->ops->port_fast_age(ds, dp->index);
 
-	dsa_port_notify_bridge_fdb_flush(dp);
+	/* flush all VLANs */
+	dsa_port_notify_bridge_fdb_flush(dp, 0);
+}
+
+static int dsa_port_vlan_fast_age(const struct dsa_port *dp, u16 vid)
+{
+	struct dsa_switch *ds = dp->ds;
+	int err;
+
+	if (!ds->ops->port_vlan_fast_age)
+		return -EOPNOTSUPP;
+
+	err = ds->ops->port_vlan_fast_age(ds, dp->index, vid);
+
+	if (!err)
+		dsa_port_notify_bridge_fdb_flush(dp, vid);
+
+	return err;
+}
+
+static int dsa_port_msti_fast_age(const struct dsa_port *dp, u16 msti)
+{
+	DECLARE_BITMAP(vids, VLAN_N_VID) = { 0 };
+	int err, vid;
+
+	err = br_mst_get_info(dsa_port_bridge_dev_get(dp), msti, vids);
+	if (err)
+		return err;
+
+	for_each_set_bit(vid, vids, VLAN_N_VID) {
+		err = dsa_port_vlan_fast_age(dp, vid);
+		if (err)
+			return err;
+	}
+
+	return 0;
 }
 
 static bool dsa_port_can_configure_learning(struct dsa_port *dp)
@@ -118,6 +152,42 @@ static void dsa_port_set_state_now(struct dsa_port *dp, u8
state,
 		pr_err("DSA: failed to set STP state %u (%d)\n", state, err);
 }
 
+int dsa_port_set_mst_state(struct dsa_port *dp,
+			   const struct switchdev_mst_state *state,
+			   struct netlink_ext_ack *extack)
+{
+	struct dsa_switch *ds = dp->ds;
+	u8 prev_state;
+	int err;
+
+	if (!ds->ops->port_mst_state_set)
+		return -EOPNOTSUPP;
+
+	err = br_mst_get_state(dsa_port_to_bridge_port(dp), state->msti,
+			       &prev_state);
+	if (err)
+		return err;
+
+	err = ds->ops->port_mst_state_set(ds, dp->index, state);
+	if (err)
+		return err;
+
+	if (!(dp->learning &&
+	      (prev_state == BR_STATE_LEARNING ||
+	       prev_state == BR_STATE_FORWARDING) &&
+	      (state->state == BR_STATE_DISABLED ||
+	       state->state == BR_STATE_BLOCKING ||
+	       state->state == BR_STATE_LISTENING)))
+		return 0;
+
+	err = dsa_port_msti_fast_age(dp, state->msti);
+	if (err)
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Unable to flush associated VLANs");
+
+	return 0;
+}
+
 int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy)
 {
 	struct dsa_switch *ds = dp->ds;
@@ -326,6 +396,8 @@ static bool dsa_port_supports_mst(struct dsa_port *dp)
 	struct dsa_switch *ds = dp->ds;
 
 	return ds->ops->vlan_msti_set &&
+		ds->ops->port_mst_state_set &&
+		ds->ops->port_vlan_fast_age &&
 		dsa_port_can_configure_learning(dp);
 }
 
@@ -749,10 +821,7 @@ int dsa_port_ageing_time(struct dsa_port *dp, clock_t
ageing_clock)
 int dsa_port_mst_enable(struct dsa_port *dp, bool on,
 			struct netlink_ext_ack *extack)
 {
-	if (!on)
-		return 0;
-
-	if (!dsa_port_supports_mst(dp)) {
+	if (on && !dsa_port_supports_mst(dp)) {
 		NL_SET_ERR_MSG_MOD(extack, "Hardware does not support MST");
 		return -EINVAL;
 	}
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 1b3e792d0327..17615b706359 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -451,6 +451,12 @@ static int dsa_slave_port_attr_set(struct net_device *dev,
const void *ctx,
 
 		ret = dsa_port_set_state(dp, attr->u.stp_state, true);
 		break;
+	case SWITCHDEV_ATTR_ID_PORT_MST_STATE:
+		if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
+			return -EOPNOTSUPP;
+
+		ret = dsa_port_set_mst_state(dp, &attr->u.mst_state, extack);
+		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
 		if (!dsa_port_offloads_bridge_dev(dp, attr->orig_dev))
 			return -EOPNOTSUPP;
-- 
2.25.1

In early LinkStreet silicon (e.g. 6095/6185), the per-VLAN STP states
were kept in the VTU - there was no concept of a SID. Later, the
information was split into two tables, where the VTU only tracked
memberships and deferred the STP state tracking to the STU via a
pointer (SID). This meant that a group of VLANs could share the same
STU entry. Most likely, this was done to align with MSTP (802.1Q-2018,
Clause 13), which is built on this principle.

While the VTU is still 4k lines on most devices, the STU is capped at
64 entries. This means that the current stategy, updating STU info
whenever a VTU entry is updated, can not easily support MSTP because:

- The maximum number of VIDs would also be capped at 64, as we would
  have to allocate one SID for every VTU entry - even if many VLANs
  would effectively share the same MST.

- MSTP updates would be unnecessarily slow as you would have to
  iterate over all VLANs that share the same MST.

In order to support MSTP offloading in the future, manage the STU as a
separate entity from the VTU.

Only add support for newer hardware with separate VTU and
STU. VTU-only devices can also be supported, but essentially this
requires a software implementation of an STU (fanning out state
changed to all VLANs tied to the same MST).

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c        |  54 ++++
 drivers/net/dsa/mv88e6xxx/chip.h        |  24 ++
 drivers/net/dsa/mv88e6xxx/global1.h     |  10 +
 drivers/net/dsa/mv88e6xxx/global1_vtu.c | 311 ++++++++++++++----------
 4 files changed, 264 insertions(+), 135 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 84b90fc36c58..c14a62aa6a6c 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1791,6 +1791,33 @@ static int mv88e6xxx_atu_new(struct mv88e6xxx_chip *chip,
u16 *fid)
 	return mv88e6xxx_g1_atu_flush(chip, *fid, true);
 }
 
+static int mv88e6xxx_stu_loadpurge(struct mv88e6xxx_chip *chip,
+				   struct mv88e6xxx_stu_entry *entry)
+{
+	if (!chip->info->ops->stu_loadpurge)
+		return -EOPNOTSUPP;
+
+	return chip->info->ops->stu_loadpurge(chip, entry);
+}
+
+static int mv88e6xxx_stu_setup(struct mv88e6xxx_chip *chip)
+{
+	struct mv88e6xxx_stu_entry stu = {
+		.valid = true,
+		.sid = 0
+	};
+
+	if (!mv88e6xxx_has_stu(chip))
+		return 0;
+
+	/* Make sure that SID 0 is always valid. This is used by VTU
+	 * entries that do not make use of the STU, e.g. when creating
+	 * a VLAN upper on a port that is also part of a VLAN
+	 * filtering bridge.
+	 */
+	return mv88e6xxx_stu_loadpurge(chip, &stu);
+}
+
 static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 					u16 vid)
 {
@@ -3427,6 +3454,13 @@ static int mv88e6xxx_setup(struct dsa_switch *ds)
 	if (err)
 		goto unlock;
 
+	/* Must be called after mv88e6xxx_vtu_setup (which flushes the
+	 * VTU, thereby also flushing the STU).
+	 */
+	err = mv88e6xxx_stu_setup(chip);
+	if (err)
+		goto unlock;
+
 	/* Setup Switch Port Registers */
 	for (i = 0; i < mv88e6xxx_num_ports(chip); i++) {
 		if (dsa_is_unused_port(ds, i))
@@ -3882,6 +3916,8 @@ static const struct mv88e6xxx_ops mv88e6097_ops = {
 	.vtu_getnext = mv88e6352_g1_vtu_getnext,
 	.vtu_loadpurge = mv88e6352_g1_vtu_loadpurge,
 	.phylink_get_caps = mv88e6095_phylink_get_caps,
+	.stu_getnext = mv88e6352_g1_stu_getnext,
+	.stu_loadpurge = mv88e6352_g1_stu_loadpurge,
 	.set_max_frame_size = mv88e6185_g1_set_max_frame_size,
 };
 
@@ -4968,6 +5004,8 @@ static const struct mv88e6xxx_ops mv88e6352_ops = {
 	.atu_set_hash = mv88e6165_g1_atu_set_hash,
 	.vtu_getnext = mv88e6352_g1_vtu_getnext,
 	.vtu_loadpurge = mv88e6352_g1_vtu_loadpurge,
+	.stu_getnext = mv88e6352_g1_stu_getnext,
+	.stu_loadpurge = mv88e6352_g1_stu_loadpurge,
 	.serdes_get_lane = mv88e6352_serdes_get_lane,
 	.serdes_pcs_get_state = mv88e6352_serdes_pcs_get_state,
 	.serdes_pcs_config = mv88e6352_serdes_pcs_config,
@@ -5033,6 +5071,8 @@ static const struct mv88e6xxx_ops mv88e6390_ops = {
 	.atu_set_hash = mv88e6165_g1_atu_set_hash,
 	.vtu_getnext = mv88e6390_g1_vtu_getnext,
 	.vtu_loadpurge = mv88e6390_g1_vtu_loadpurge,
+	.stu_getnext = mv88e6390_g1_stu_getnext,
+	.stu_loadpurge = mv88e6390_g1_stu_loadpurge,
 	.serdes_power = mv88e6390_serdes_power,
 	.serdes_get_lane = mv88e6390_serdes_get_lane,
 	/* Check status register pause & lpa register */
@@ -5098,6 +5138,8 @@ static const struct mv88e6xxx_ops mv88e6390x_ops = {
 	.atu_set_hash = mv88e6165_g1_atu_set_hash,
 	.vtu_getnext = mv88e6390_g1_vtu_getnext,
 	.vtu_loadpurge = mv88e6390_g1_vtu_loadpurge,
+	.stu_getnext = mv88e6390_g1_stu_getnext,
+	.stu_loadpurge = mv88e6390_g1_stu_loadpurge,
 	.serdes_power = mv88e6390_serdes_power,
 	.serdes_get_lane = mv88e6390x_serdes_get_lane,
 	.serdes_pcs_get_state = mv88e6390_serdes_pcs_get_state,
@@ -5166,6 +5208,8 @@ static const struct mv88e6xxx_ops mv88e6393x_ops = {
 	.atu_set_hash = mv88e6165_g1_atu_set_hash,
 	.vtu_getnext = mv88e6390_g1_vtu_getnext,
 	.vtu_loadpurge = mv88e6390_g1_vtu_loadpurge,
+	.stu_getnext = mv88e6390_g1_stu_getnext,
+	.stu_loadpurge = mv88e6390_g1_stu_loadpurge,
 	.serdes_power = mv88e6393x_serdes_power,
 	.serdes_get_lane = mv88e6393x_serdes_get_lane,
 	.serdes_pcs_get_state = mv88e6393x_serdes_pcs_get_state,
@@ -5234,6 +5278,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_ports = 11,
 		.num_internal_phys = 8,
 		.max_vid = 4095,
+		.max_sid = 63,
 		.port_base_addr = 0x10,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5487,6 +5532,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_internal_phys = 9,
 		.num_gpio = 16,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5510,6 +5556,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_internal_phys = 9,
 		.num_gpio = 16,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5532,6 +5579,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5554,6 +5602,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5576,6 +5625,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5815,6 +5865,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_internal_phys = 5,
 		.num_gpio = 15,
 		.max_vid = 4095,
+		.max_sid = 63,
 		.port_base_addr = 0x10,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5839,6 +5890,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_internal_phys = 9,
 		.num_gpio = 16,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5863,6 +5915,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_internal_phys = 9,
 		.num_gpio = 16,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
@@ -5886,6 +5939,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
 		.num_ports = 11,	/* 10 + Z80 */
 		.num_internal_phys = 9,
 		.max_vid = 8191,
+		.max_sid = 63,
 		.port_base_addr = 0x0,
 		.phy_base_addr = 0x0,
 		.global1_addr = 0x1b,
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 30b92a265613..be654be69982 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -20,6 +20,7 @@
 
 #define EDSA_HLEN		8
 #define MV88E6XXX_N_FID		4096
+#define MV88E6XXX_N_SID		64
 
 #define MV88E6XXX_FID_STANDALONE	0
 #define MV88E6XXX_FID_BRIDGED		1
@@ -130,6 +131,7 @@ struct mv88e6xxx_info {
 	unsigned int num_internal_phys;
 	unsigned int num_gpio;
 	unsigned int max_vid;
+	unsigned int max_sid;
 	unsigned int port_base_addr;
 	unsigned int phy_base_addr;
 	unsigned int global1_addr;
@@ -181,6 +183,12 @@ struct mv88e6xxx_vtu_entry {
 	bool	valid;
 	bool	policy;
 	u8	member[DSA_MAX_PORTS];
+	u8	state[DSA_MAX_PORTS];	/* Older silicon has no STU */
+};
+
+struct mv88e6xxx_stu_entry {
+	u8	sid;
+	bool	valid;
 	u8	state[DSA_MAX_PORTS];
 };
 
@@ -602,6 +610,12 @@ struct mv88e6xxx_ops {
 	int (*vtu_loadpurge)(struct mv88e6xxx_chip *chip,
 			     struct mv88e6xxx_vtu_entry *entry);
 
+	/* Spanning Tree Unit operations */
+	int (*stu_getnext)(struct mv88e6xxx_chip *chip,
+			   struct mv88e6xxx_stu_entry *entry);
+	int (*stu_loadpurge)(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry);
+
 	/* GPIO operations */
 	const struct mv88e6xxx_gpio_ops *gpio_ops;
 
@@ -700,6 +714,11 @@ struct mv88e6xxx_hw_stat {
 	int type;
 };
 
+static inline bool mv88e6xxx_has_stu(struct mv88e6xxx_chip *chip)
+{
+	return chip->info->max_sid > 0;
+}
+
 static inline bool mv88e6xxx_has_pvt(struct mv88e6xxx_chip *chip)
 {
 	return chip->info->pvt;
@@ -730,6 +749,11 @@ static inline unsigned int mv88e6xxx_max_vid(struct
mv88e6xxx_chip *chip)
 	return chip->info->max_vid;
 }
 
+static inline unsigned int mv88e6xxx_max_sid(struct mv88e6xxx_chip *chip)
+{
+	return chip->info->max_sid;
+}
+
 static inline u16 mv88e6xxx_port_mask(struct mv88e6xxx_chip *chip)
 {
 	return GENMASK((s32)mv88e6xxx_num_ports(chip) - 1, 0);
diff --git a/drivers/net/dsa/mv88e6xxx/global1.h
b/drivers/net/dsa/mv88e6xxx/global1.h
index 2c1607c858a1..65958b2a0d3a 100644
--- a/drivers/net/dsa/mv88e6xxx/global1.h
+++ b/drivers/net/dsa/mv88e6xxx/global1.h
@@ -348,6 +348,16 @@ int mv88e6390_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 int mv88e6390_g1_vtu_loadpurge(struct mv88e6xxx_chip *chip,
 			       struct mv88e6xxx_vtu_entry *entry);
 int mv88e6xxx_g1_vtu_flush(struct mv88e6xxx_chip *chip);
+int mv88e6xxx_g1_stu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry);
+int mv88e6352_g1_stu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry);
+int mv88e6352_g1_stu_loadpurge(struct mv88e6xxx_chip *chip,
+			       struct mv88e6xxx_stu_entry *entry);
+int mv88e6390_g1_stu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry);
+int mv88e6390_g1_stu_loadpurge(struct mv88e6xxx_chip *chip,
+			       struct mv88e6xxx_stu_entry *entry);
 int mv88e6xxx_g1_vtu_prob_irq_setup(struct mv88e6xxx_chip *chip);
 void mv88e6xxx_g1_vtu_prob_irq_free(struct mv88e6xxx_chip *chip);
 int mv88e6xxx_g1_atu_get_next(struct mv88e6xxx_chip *chip, u16 fid);
diff --git a/drivers/net/dsa/mv88e6xxx/global1_vtu.c
b/drivers/net/dsa/mv88e6xxx/global1_vtu.c
index b1bd9274a562..38e18f5811bf 100644
--- a/drivers/net/dsa/mv88e6xxx/global1_vtu.c
+++ b/drivers/net/dsa/mv88e6xxx/global1_vtu.c
@@ -44,8 +44,7 @@ static int mv88e6xxx_g1_vtu_fid_write(struct mv88e6xxx_chip
*chip,
 
 /* Offset 0x03: VTU SID Register */
 
-static int mv88e6xxx_g1_vtu_sid_read(struct mv88e6xxx_chip *chip,
-				     struct mv88e6xxx_vtu_entry *entry)
+static int mv88e6xxx_g1_vtu_sid_read(struct mv88e6xxx_chip *chip, u8 *sid)
 {
 	u16 val;
 	int err;
@@ -54,15 +53,14 @@ static int mv88e6xxx_g1_vtu_sid_read(struct mv88e6xxx_chip
*chip,
 	if (err)
 		return err;
 
-	entry->sid = val & MV88E6352_G1_VTU_SID_MASK;
+	*sid = val & MV88E6352_G1_VTU_SID_MASK;
 
 	return 0;
 }
 
-static int mv88e6xxx_g1_vtu_sid_write(struct mv88e6xxx_chip *chip,
-				      struct mv88e6xxx_vtu_entry *entry)
+static int mv88e6xxx_g1_vtu_sid_write(struct mv88e6xxx_chip *chip, u8 sid)
 {
-	u16 val = entry->sid & MV88E6352_G1_VTU_SID_MASK;
+	u16 val = sid & MV88E6352_G1_VTU_SID_MASK;
 
 	return mv88e6xxx_g1_write(chip, MV88E6352_G1_VTU_SID, val);
 }
@@ -91,7 +89,7 @@ static int mv88e6xxx_g1_vtu_op(struct mv88e6xxx_chip *chip,
u16 op)
 /* Offset 0x06: VTU VID Register */
 
 static int mv88e6xxx_g1_vtu_vid_read(struct mv88e6xxx_chip *chip,
-				     struct mv88e6xxx_vtu_entry *entry)
+				     bool *valid, u16 *vid)
 {
 	u16 val;
 	int err;
@@ -100,25 +98,28 @@ static int mv88e6xxx_g1_vtu_vid_read(struct mv88e6xxx_chip
*chip,
 	if (err)
 		return err;
 
-	entry->vid = val & 0xfff;
+	if (vid) {
+		*vid = val & 0xfff;
 
-	if (val & MV88E6390_G1_VTU_VID_PAGE)
-		entry->vid |= 0x1000;
+		if (val & MV88E6390_G1_VTU_VID_PAGE)
+			*vid |= 0x1000;
+	}
 
-	entry->valid = !!(val & MV88E6XXX_G1_VTU_VID_VALID);
+	if (valid)
+		*valid = !!(val & MV88E6XXX_G1_VTU_VID_VALID);
 
 	return 0;
 }
 
 static int mv88e6xxx_g1_vtu_vid_write(struct mv88e6xxx_chip *chip,
-				      struct mv88e6xxx_vtu_entry *entry)
+				      bool valid, u16 vid)
 {
-	u16 val = entry->vid & 0xfff;
+	u16 val = vid & 0xfff;
 
-	if (entry->vid & 0x1000)
+	if (vid & 0x1000)
 		val |= MV88E6390_G1_VTU_VID_PAGE;
 
-	if (entry->valid)
+	if (valid)
 		val |= MV88E6XXX_G1_VTU_VID_VALID;
 
 	return mv88e6xxx_g1_write(chip, MV88E6XXX_G1_VTU_VID, val);
@@ -147,7 +148,7 @@ static int mv88e6185_g1_vtu_stu_data_read(struct
mv88e6xxx_chip *chip,
 }
 
 static int mv88e6185_g1_vtu_data_read(struct mv88e6xxx_chip *chip,
-				      struct mv88e6xxx_vtu_entry *entry)
+				      u8 *member, u8 *state)
 {
 	u16 regs[3];
 	int err;
@@ -160,36 +161,20 @@ static int mv88e6185_g1_vtu_data_read(struct
mv88e6xxx_chip *chip,
 	/* Extract MemberTag data */
 	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
 		unsigned int member_offset = (i % 4) * 4;
+		unsigned int state_offset = member_offset + 2;
 
-		entry->member[i] = (regs[i / 4] >> member_offset) & 0x3;
-	}
-
-	return 0;
-}
-
-static int mv88e6185_g1_stu_data_read(struct mv88e6xxx_chip *chip,
-				      struct mv88e6xxx_vtu_entry *entry)
-{
-	u16 regs[3];
-	int err;
-	int i;
-
-	err = mv88e6185_g1_vtu_stu_data_read(chip, regs);
-	if (err)
-		return err;
+		if (member)
+			member[i] = (regs[i / 4] >> member_offset) & 0x3;
 
-	/* Extract PortState data */
-	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
-		unsigned int state_offset = (i % 4) * 4 + 2;
-
-		entry->state[i] = (regs[i / 4] >> state_offset) & 0x3;
+		if (state)
+			state[i] = (regs[i / 4] >> state_offset) & 0x3;
 	}
 
 	return 0;
 }
 
 static int mv88e6185_g1_vtu_data_write(struct mv88e6xxx_chip *chip,
-				       struct mv88e6xxx_vtu_entry *entry)
+				       u8 *member, u8 *state)
 {
 	u16 regs[3] = { 0 };
 	int i;
@@ -199,8 +184,11 @@ static int mv88e6185_g1_vtu_data_write(struct
mv88e6xxx_chip *chip,
 		unsigned int member_offset = (i % 4) * 4;
 		unsigned int state_offset = member_offset + 2;
 
-		regs[i / 4] |= (entry->member[i] & 0x3) << member_offset;
-		regs[i / 4] |= (entry->state[i] & 0x3) << state_offset;
+		if (member)
+			regs[i / 4] |= (member[i] & 0x3) << member_offset;
+
+		if (state)
+			regs[i / 4] |= (state[i] & 0x3) << state_offset;
 	}
 
 	/* Write all 3 VTU/STU Data registers */
@@ -268,48 +256,6 @@ static int mv88e6390_g1_vtu_data_write(struct
mv88e6xxx_chip *chip, u8 *data)
 
 /* VLAN Translation Unit Operations */
 
-static int mv88e6xxx_g1_vtu_stu_getnext(struct mv88e6xxx_chip *chip,
-					struct mv88e6xxx_vtu_entry *entry)
-{
-	int err;
-
-	err = mv88e6xxx_g1_vtu_sid_write(chip, entry);
-	if (err)
-		return err;
-
-	err = mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_STU_GET_NEXT);
-	if (err)
-		return err;
-
-	err = mv88e6xxx_g1_vtu_sid_read(chip, entry);
-	if (err)
-		return err;
-
-	return mv88e6xxx_g1_vtu_vid_read(chip, entry);
-}
-
-static int mv88e6xxx_g1_vtu_stu_get(struct mv88e6xxx_chip *chip,
-				    struct mv88e6xxx_vtu_entry *vtu)
-{
-	struct mv88e6xxx_vtu_entry stu;
-	int err;
-
-	err = mv88e6xxx_g1_vtu_sid_read(chip, vtu);
-	if (err)
-		return err;
-
-	stu.sid = vtu->sid - 1;
-
-	err = mv88e6xxx_g1_vtu_stu_getnext(chip, &stu);
-	if (err)
-		return err;
-
-	if (stu.sid != vtu->sid || !stu.valid)
-		return -EINVAL;
-
-	return 0;
-}
-
 int mv88e6xxx_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 			     struct mv88e6xxx_vtu_entry *entry)
 {
@@ -327,7 +273,7 @@ int mv88e6xxx_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 	 * write the VID only once, when the entry is given as invalid.
 	 */
 	if (!entry->valid) {
-		err = mv88e6xxx_g1_vtu_vid_write(chip, entry);
+		err = mv88e6xxx_g1_vtu_vid_write(chip, false, entry->vid);
 		if (err)
 			return err;
 	}
@@ -336,7 +282,7 @@ int mv88e6xxx_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 	if (err)
 		return err;
 
-	return mv88e6xxx_g1_vtu_vid_read(chip, entry);
+	return mv88e6xxx_g1_vtu_vid_read(chip, &entry->valid,
&entry->vid);
 }
 
 int mv88e6185_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
@@ -350,11 +296,7 @@ int mv88e6185_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 		return err;
 
 	if (entry->valid) {
-		err = mv88e6185_g1_vtu_data_read(chip, entry);
-		if (err)
-			return err;
-
-		err = mv88e6185_g1_stu_data_read(chip, entry);
+		err = mv88e6185_g1_vtu_data_read(chip, entry->member, entry->state);
 		if (err)
 			return err;
 
@@ -384,7 +326,7 @@ int mv88e6352_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 		return err;
 
 	if (entry->valid) {
-		err = mv88e6185_g1_vtu_data_read(chip, entry);
+		err = mv88e6185_g1_vtu_data_read(chip, entry->member, NULL);
 		if (err)
 			return err;
 
@@ -392,12 +334,7 @@ int mv88e6352_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 		if (err)
 			return err;
 
-		/* Fetch VLAN PortState data from the STU */
-		err = mv88e6xxx_g1_vtu_stu_get(chip, entry);
-		if (err)
-			return err;
-
-		err = mv88e6185_g1_stu_data_read(chip, entry);
+		err = mv88e6xxx_g1_vtu_sid_read(chip, &entry->sid);
 		if (err)
 			return err;
 	}
@@ -420,16 +357,11 @@ int mv88e6390_g1_vtu_getnext(struct mv88e6xxx_chip *chip,
 		if (err)
 			return err;
 
-		/* Fetch VLAN PortState data from the STU */
-		err = mv88e6xxx_g1_vtu_stu_get(chip, entry);
-		if (err)
-			return err;
-
-		err = mv88e6390_g1_vtu_data_read(chip, entry->state);
+		err = mv88e6xxx_g1_vtu_fid_read(chip, entry);
 		if (err)
 			return err;
 
-		err = mv88e6xxx_g1_vtu_fid_read(chip, entry);
+		err = mv88e6xxx_g1_vtu_sid_read(chip, &entry->sid);
 		if (err)
 			return err;
 	}
@@ -447,12 +379,12 @@ int mv88e6185_g1_vtu_loadpurge(struct mv88e6xxx_chip
*chip,
 	if (err)
 		return err;
 
-	err = mv88e6xxx_g1_vtu_vid_write(chip, entry);
+	err = mv88e6xxx_g1_vtu_vid_write(chip, entry->valid, entry->vid);
 	if (err)
 		return err;
 
 	if (entry->valid) {
-		err = mv88e6185_g1_vtu_data_write(chip, entry);
+		err = mv88e6185_g1_vtu_data_write(chip, entry->member, entry->state);
 		if (err)
 			return err;
 
@@ -479,27 +411,21 @@ int mv88e6352_g1_vtu_loadpurge(struct mv88e6xxx_chip
*chip,
 	if (err)
 		return err;
 
-	err = mv88e6xxx_g1_vtu_vid_write(chip, entry);
+	err = mv88e6xxx_g1_vtu_vid_write(chip, entry->valid, entry->vid);
 	if (err)
 		return err;
 
 	if (entry->valid) {
-		/* Write MemberTag and PortState data */
-		err = mv88e6185_g1_vtu_data_write(chip, entry);
-		if (err)
-			return err;
-
-		err = mv88e6xxx_g1_vtu_sid_write(chip, entry);
+		/* Write MemberTag data */
+		err = mv88e6185_g1_vtu_data_write(chip, entry->member, NULL);
 		if (err)
 			return err;
 
-		/* Load STU entry */
-		err = mv88e6xxx_g1_vtu_op(chip,
-					  MV88E6XXX_G1_VTU_OP_STU_LOAD_PURGE);
+		err = mv88e6xxx_g1_vtu_fid_write(chip, entry);
 		if (err)
 			return err;
 
-		err = mv88e6xxx_g1_vtu_fid_write(chip, entry);
+		err = mv88e6xxx_g1_vtu_sid_write(chip, entry->sid);
 		if (err)
 			return err;
 	}
@@ -517,41 +443,113 @@ int mv88e6390_g1_vtu_loadpurge(struct mv88e6xxx_chip
*chip,
 	if (err)
 		return err;
 
-	err = mv88e6xxx_g1_vtu_vid_write(chip, entry);
+	err = mv88e6xxx_g1_vtu_vid_write(chip, entry->valid, entry->vid);
 	if (err)
 		return err;
 
 	if (entry->valid) {
-		/* Write PortState data */
-		err = mv88e6390_g1_vtu_data_write(chip, entry->state);
+		/* Write MemberTag data */
+		err = mv88e6390_g1_vtu_data_write(chip, entry->member);
 		if (err)
 			return err;
 
-		err = mv88e6xxx_g1_vtu_sid_write(chip, entry);
+		err = mv88e6xxx_g1_vtu_fid_write(chip, entry);
 		if (err)
 			return err;
 
-		/* Load STU entry */
-		err = mv88e6xxx_g1_vtu_op(chip,
-					  MV88E6XXX_G1_VTU_OP_STU_LOAD_PURGE);
+		err = mv88e6xxx_g1_vtu_sid_write(chip, entry->sid);
 		if (err)
 			return err;
+	}
 
-		/* Write MemberTag data */
-		err = mv88e6390_g1_vtu_data_write(chip, entry->member);
+	/* Load/Purge VTU entry */
+	return mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_VTU_LOAD_PURGE);
+}
+
+int mv88e6xxx_g1_vtu_flush(struct mv88e6xxx_chip *chip)
+{
+	int err;
+
+	err = mv88e6xxx_g1_vtu_op_wait(chip);
+	if (err)
+		return err;
+
+	return mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_FLUSH_ALL);
+}
+
+/* Spanning Tree Unit Operations */
+
+int mv88e6xxx_g1_stu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry)
+{
+	int err;
+
+	err = mv88e6xxx_g1_vtu_op_wait(chip);
+	if (err)
+		return err;
+
+	/* To get the next higher active SID, the STU GetNext operation can be
+	 * started again without setting the SID registers since it already
+	 * contains the last SID.
+	 *
+	 * To save a few hardware accesses and abstract this to the caller,
+	 * write the SID only once, when the entry is given as invalid.
+	 */
+	if (!entry->valid) {
+		err = mv88e6xxx_g1_vtu_sid_write(chip, entry->sid);
 		if (err)
 			return err;
+	}
 
-		err = mv88e6xxx_g1_vtu_fid_write(chip, entry);
+	err = mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_STU_GET_NEXT);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g1_vtu_vid_read(chip, &entry->valid, NULL);
+	if (err)
+		return err;
+
+	if (entry->valid) {
+		err = mv88e6xxx_g1_vtu_sid_read(chip, &entry->sid);
 		if (err)
 			return err;
 	}
 
-	/* Load/Purge VTU entry */
-	return mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_VTU_LOAD_PURGE);
+	return 0;
 }
 
-int mv88e6xxx_g1_vtu_flush(struct mv88e6xxx_chip *chip)
+int mv88e6352_g1_stu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry)
+{
+	int err;
+
+	err = mv88e6xxx_g1_stu_getnext(chip, entry);
+	if (err)
+		return err;
+
+	if (!entry->valid)
+		return 0;
+
+	return mv88e6185_g1_vtu_data_read(chip, NULL, entry->state);
+}
+
+int mv88e6390_g1_stu_getnext(struct mv88e6xxx_chip *chip,
+			     struct mv88e6xxx_stu_entry *entry)
+{
+	int err;
+
+	err = mv88e6xxx_g1_stu_getnext(chip, entry);
+	if (err)
+		return err;
+
+	if (!entry->valid)
+		return 0;
+
+	return mv88e6390_g1_vtu_data_read(chip, entry->state);
+}
+
+int mv88e6352_g1_stu_loadpurge(struct mv88e6xxx_chip *chip,
+			       struct mv88e6xxx_stu_entry *entry)
 {
 	int err;
 
@@ -559,16 +557,59 @@ int mv88e6xxx_g1_vtu_flush(struct mv88e6xxx_chip *chip)
 	if (err)
 		return err;
 
-	return mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_FLUSH_ALL);
+	err = mv88e6xxx_g1_vtu_vid_write(chip, entry->valid, 0);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g1_vtu_sid_write(chip, entry->sid);
+	if (err)
+		return err;
+
+	if (entry->valid) {
+		err = mv88e6185_g1_vtu_data_write(chip, NULL, entry->state);
+		if (err)
+			return err;
+	}
+
+	/* Load/Purge STU entry */
+	return mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_STU_LOAD_PURGE);
+}
+
+int mv88e6390_g1_stu_loadpurge(struct mv88e6xxx_chip *chip,
+			       struct mv88e6xxx_stu_entry *entry)
+{
+	int err;
+
+	err = mv88e6xxx_g1_vtu_op_wait(chip);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g1_vtu_vid_write(chip, entry->valid, 0);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g1_vtu_sid_write(chip, entry->sid);
+	if (err)
+		return err;
+
+	if (entry->valid) {
+		err = mv88e6390_g1_vtu_data_write(chip, entry->state);
+		if (err)
+			return err;
+	}
+
+	/* Load/Purge STU entry */
+	return mv88e6xxx_g1_vtu_op(chip, MV88E6XXX_G1_VTU_OP_STU_LOAD_PURGE);
 }
 
+/* VTU Violation Management */
+
 static irqreturn_t mv88e6xxx_g1_vtu_prob_irq_thread_fn(int irq, void *dev_id)
 {
 	struct mv88e6xxx_chip *chip = dev_id;
-	struct mv88e6xxx_vtu_entry entry;
+	u16 val, vid;
 	int spid;
 	int err;
-	u16 val;
 
 	mv88e6xxx_reg_lock(chip);
 
@@ -580,7 +621,7 @@ static irqreturn_t mv88e6xxx_g1_vtu_prob_irq_thread_fn(int
irq, void *dev_id)
 	if (err)
 		goto out;
 
-	err = mv88e6xxx_g1_vtu_vid_read(chip, &entry);
+	err = mv88e6xxx_g1_vtu_vid_read(chip, NULL, &vid);
 	if (err)
 		goto out;
 
@@ -588,13 +629,13 @@ static irqreturn_t mv88e6xxx_g1_vtu_prob_irq_thread_fn(int
irq, void *dev_id)
 
 	if (val & MV88E6XXX_G1_VTU_OP_MEMBER_VIOLATION) {
 		dev_err_ratelimited(chip->dev, "VTU member violation for vid %d,
source port %d\n",
-				    entry.vid, spid);
+				    vid, spid);
 		chip->ports[spid].vtu_member_violation++;
 	}
 
 	if (val & MV88E6XXX_G1_VTU_OP_MISS_VIOLATION) {
 		dev_dbg_ratelimited(chip->dev, "VTU miss violation for vid %d, source
port %d\n",
-				    entry.vid, spid);
+				    vid, spid);
 		chip->ports[spid].vtu_miss_violation++;
 	}
 
-- 
2.25.1

Export the raw STU data in a devlink region so that it can be
inspected from userspace and compared to the current bridge
configuration.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 drivers/net/dsa/mv88e6xxx/chip.h    |  1 +
 drivers/net/dsa/mv88e6xxx/devlink.c | 94 +++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index be654be69982..6d4daa24d3e5 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -287,6 +287,7 @@ enum mv88e6xxx_region_id {
 	MV88E6XXX_REGION_GLOBAL2,
 	MV88E6XXX_REGION_ATU,
 	MV88E6XXX_REGION_VTU,
+	MV88E6XXX_REGION_STU,
 	MV88E6XXX_REGION_PVT,
 
 	_MV88E6XXX_REGION_MAX,
diff --git a/drivers/net/dsa/mv88e6xxx/devlink.c
b/drivers/net/dsa/mv88e6xxx/devlink.c
index 381068395c63..1266eabee086 100644
--- a/drivers/net/dsa/mv88e6xxx/devlink.c
+++ b/drivers/net/dsa/mv88e6xxx/devlink.c
@@ -503,6 +503,85 @@ static int mv88e6xxx_region_vtu_snapshot(struct devlink
*dl,
 	return 0;
 }
 
+/**
+ * struct mv88e6xxx_devlink_stu_entry - Devlink STU entry
+ * @sid:   Global1/3:   SID, unknown filters and learning.
+ * @vid:   Global1/6:   Valid bit.
+ * @data:  Global1/7-9: Membership data and priority override.
+ * @resvd: Reserved. In case we forgot something.
+ *
+ * The STU entry format varies between chipset generations. Peridot
+ * and Amethyst packs the STU data into Global1/7-8. Older silicon
+ * spreads the information across all three VTU data registers -
+ * inheriting the layout of even older hardware that had no STU at
+ * all. Since this is a low-level debug interface, copy all data
+ * verbatim and defer parsing to the consumer.
+ */
+struct mv88e6xxx_devlink_stu_entry {
+	u16 sid;
+	u16 vid;
+	u16 data[3];
+	u16 resvd;
+};
+
+static int mv88e6xxx_region_stu_snapshot(struct devlink *dl,
+					 const struct devlink_region_ops *ops,
+					 struct netlink_ext_ack *extack,
+					 u8 **data)
+{
+	struct mv88e6xxx_devlink_stu_entry *table, *entry;
+	struct dsa_switch *ds = dsa_devlink_to_ds(dl);
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_stu_entry stu;
+	int err;
+
+	table = kcalloc(mv88e6xxx_max_sid(chip) + 1,
+			sizeof(struct mv88e6xxx_devlink_stu_entry),
+			GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	entry = table;
+	stu.sid = mv88e6xxx_max_sid(chip);
+	stu.valid = false;
+
+	mv88e6xxx_reg_lock(chip);
+
+	do {
+		err = mv88e6xxx_g1_stu_getnext(chip, &stu);
+		if (err)
+			break;
+
+		if (!stu.valid)
+			break;
+
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6352_G1_VTU_SID,
+						&entry->sid);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_VID,
+						&entry->vid);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_DATA1,
+						&entry->data[0]);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_DATA2,
+						&entry->data[1]);
+		err = err ? : mv88e6xxx_g1_read(chip, MV88E6XXX_G1_VTU_DATA3,
+						&entry->data[2]);
+		if (err)
+			break;
+
+		entry++;
+	} while (stu.sid < mv88e6xxx_max_sid(chip));
+
+	mv88e6xxx_reg_unlock(chip);
+
+	if (err) {
+		kfree(table);
+		return err;
+	}
+
+	*data = (u8 *)table;
+	return 0;
+}
+
 static int mv88e6xxx_region_pvt_snapshot(struct devlink *dl,
 					 const struct devlink_region_ops *ops,
 					 struct netlink_ext_ack *extack,
@@ -605,6 +684,12 @@ static struct devlink_region_ops mv88e6xxx_region_vtu_ops =
{
 	.destructor = kfree,
 };
 
+static struct devlink_region_ops mv88e6xxx_region_stu_ops = {
+	.name = "stu",
+	.snapshot = mv88e6xxx_region_stu_snapshot,
+	.destructor = kfree,
+};
+
 static struct devlink_region_ops mv88e6xxx_region_pvt_ops = {
 	.name = "pvt",
 	.snapshot = mv88e6xxx_region_pvt_snapshot,
@@ -640,6 +725,11 @@ static struct mv88e6xxx_region mv88e6xxx_regions[] = {
 		.ops = &mv88e6xxx_region_vtu_ops
 	  /* calculated at runtime */
 	},
+	[MV88E6XXX_REGION_STU] = {
+		.ops = &mv88e6xxx_region_stu_ops,
+		.cond = mv88e6xxx_has_stu,
+	  /* calculated at runtime */
+	},
 	[MV88E6XXX_REGION_PVT] = {
 		.ops = &mv88e6xxx_region_pvt_ops,
 		.size = MV88E6XXX_MAX_PVT_ENTRIES * sizeof(u16),
@@ -706,6 +796,10 @@ int mv88e6xxx_setup_devlink_regions_global(struct
dsa_switch *ds)
 			size = (mv88e6xxx_max_vid(chip) + 1) *
 				sizeof(struct mv88e6xxx_devlink_vtu_entry);
 			break;
+		case MV88E6XXX_REGION_STU:
+			size = (mv88e6xxx_max_sid(chip) + 1) *
+				sizeof(struct mv88e6xxx_devlink_stu_entry);
+			break;
 		}
 
 		region = dsa_devlink_region_create(ds, ops, 1, size);
-- 
2.25.1

Allocate a SID in the STU for each MSTID in use by a bridge and handle
the mapping of MSTIDs to VLANs using the SID field of each VTU entry.

Signed-off-by: Tobias Waldekranz <tobias at waldekranz.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 250 ++++++++++++++++++++++++++++++-
 drivers/net/dsa/mv88e6xxx/chip.h |  13 ++
 2 files changed, 255 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c14a62aa6a6c..bed1a5658eac 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1667,24 +1667,31 @@ static int mv88e6xxx_pvt_setup(struct mv88e6xxx_chip
*chip)
 	return 0;
 }
 
-static void mv88e6xxx_port_fast_age(struct dsa_switch *ds, int port)
+static int mv88e6xxx_port_fast_age_fid(struct mv88e6xxx_chip *chip, int port,
+				       u16 fid)
 {
-	struct mv88e6xxx_chip *chip = ds->priv;
-	int err;
-
-	if (dsa_to_port(ds, port)->lag)
+	if (dsa_to_port(chip->ds, port)->lag)
 		/* Hardware is incapable of fast-aging a LAG through a
 		 * regular ATU move operation. Until we have something
 		 * more fancy in place this is a no-op.
 		 */
-		return;
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_g1_atu_remove(chip, fid, port, false);
+}
+
+static void mv88e6xxx_port_fast_age(struct dsa_switch *ds, int port)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+	int err;
 
 	mv88e6xxx_reg_lock(chip);
-	err = mv88e6xxx_g1_atu_remove(chip, 0, port, false);
+	err = mv88e6xxx_port_fast_age_fid(chip, port, 0);
 	mv88e6xxx_reg_unlock(chip);
 
 	if (err)
-		dev_err(ds->dev, "p%d: failed to flush ATU\n", port);
+		dev_err(chip->ds->dev, "p%d: failed to flush ATU: %d\n",
+			port, err);
 }
 
 static int mv88e6xxx_vtu_setup(struct mv88e6xxx_chip *chip)
@@ -1818,6 +1825,160 @@ static int mv88e6xxx_stu_setup(struct mv88e6xxx_chip
*chip)
 	return mv88e6xxx_stu_loadpurge(chip, &stu);
 }
 
+static int mv88e6xxx_sid_get(struct mv88e6xxx_chip *chip, u8 *sid)
+{
+	DECLARE_BITMAP(busy, MV88E6XXX_N_SID) = { 0 };
+	struct mv88e6xxx_mst *mst;
+
+	__set_bit(0, busy);
+
+	list_for_each_entry(mst, &chip->msts, node)
+		__set_bit(mst->stu.sid, busy);
+
+	*sid = find_first_zero_bit(busy, MV88E6XXX_N_SID);
+
+	return (*sid >= mv88e6xxx_max_sid(chip)) ? -ENOSPC : 0;
+}
+
+static int mv88e6xxx_mst_put(struct mv88e6xxx_chip *chip, u8 sid)
+{
+	struct mv88e6xxx_mst *mst, *tmp;
+	int err;
+
+	if (!sid)
+		return 0;
+
+	list_for_each_entry_safe(mst, tmp, &chip->msts, node) {
+		if (mst->stu.sid != sid)
+			continue;
+
+		if (!refcount_dec_and_test(&mst->refcnt))
+			return 0;
+
+		mst->stu.valid = false;
+		err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
+		if (err) {
+			refcount_set(&mst->refcnt, 1);
+			return err;
+		}
+
+		list_del(&mst->node);
+		kfree(mst);
+		return 0;
+	}
+
+	return -ENOENT;
+}
+
+static int mv88e6xxx_mst_get(struct mv88e6xxx_chip *chip, struct net_device
*br,
+			     u16 msti, u8 *sid)
+{
+	struct mv88e6xxx_mst *mst;
+	int err, i;
+
+	if (!mv88e6xxx_has_stu(chip)) {
+		err = -EOPNOTSUPP;
+		goto err;
+	}
+
+	if (!msti) {
+		*sid = 0;
+		return 0;
+	}
+
+	list_for_each_entry(mst, &chip->msts, node) {
+		if (mst->br == br && mst->msti == msti) {
+			refcount_inc(&mst->refcnt);
+			*sid = mst->stu.sid;
+			return 0;
+		}
+	}
+
+	err = mv88e6xxx_sid_get(chip, sid);
+	if (err)
+		goto err;
+
+	mst = kzalloc(sizeof(*mst), GFP_KERNEL);
+	if (!mst) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	INIT_LIST_HEAD(&mst->node);
+	refcount_set(&mst->refcnt, 1);
+	mst->br = br;
+	mst->msti = msti;
+	mst->stu.valid = true;
+	mst->stu.sid = *sid;
+
+	/* The bridge starts out all ports in the disabled state. But
+	 * a STU state of disabled means to go by the port-global
+	 * state. So we set all user port's initial state to blocking,
+	 * to match the bridge's behavior.
+	 */
+	for (i = 0; i < mv88e6xxx_num_ports(chip); i++)
+		mst->stu.state[i] = dsa_is_user_port(chip->ds, i) ?
+			MV88E6XXX_PORT_CTL0_STATE_BLOCKING :
+			MV88E6XXX_PORT_CTL0_STATE_DISABLED;
+
+	err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
+	if (err)
+		goto err_free;
+
+	list_add_tail(&mst->node, &chip->msts);
+	return 0;
+
+err_free:
+	kfree(mst);
+err:
+	return err;
+}
+
+static int mv88e6xxx_port_mst_state_set(struct dsa_switch *ds, int port,
+					const struct switchdev_mst_state *st)
+{
+	struct dsa_port *dp = dsa_to_port(ds, port);
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_mst *mst;
+	u8 state;
+	int err;
+
+	if (!mv88e6xxx_has_stu(chip))
+		return -EOPNOTSUPP;
+
+	switch (st->state) {
+	case BR_STATE_DISABLED:
+	case BR_STATE_BLOCKING:
+	case BR_STATE_LISTENING:
+		state = MV88E6XXX_PORT_CTL0_STATE_BLOCKING;
+		break;
+	case BR_STATE_LEARNING:
+		state = MV88E6XXX_PORT_CTL0_STATE_LEARNING;
+		break;
+	case BR_STATE_FORWARDING:
+		state = MV88E6XXX_PORT_CTL0_STATE_FORWARDING;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	list_for_each_entry(mst, &chip->msts, node) {
+		if (mst->br == dsa_port_bridge_dev_get(dp) &&
+		    mst->msti == st->msti) {
+			if (mst->stu.state[port] == state)
+				return 0;
+
+			mst->stu.state[port] = state;
+			mv88e6xxx_reg_lock(chip);
+			err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
+			mv88e6xxx_reg_unlock(chip);
+			return err;
+		}
+	}
+
+	return -ENOENT;
+}
+
 static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 					u16 vid)
 {
@@ -2437,6 +2598,12 @@ static int mv88e6xxx_port_vlan_leave(struct
mv88e6xxx_chip *chip,
 	if (err)
 		return err;
 
+	if (!vlan.valid) {
+		err = mv88e6xxx_mst_put(chip, vlan.sid);
+		if (err)
+			return err;
+	}
+
 	return mv88e6xxx_g1_atu_remove(chip, vlan.fid, port, false);
 }
 
@@ -2482,6 +2649,69 @@ static int mv88e6xxx_port_vlan_del(struct dsa_switch *ds,
int port,
 	return err;
 }
 
+static int mv88e6xxx_port_vlan_fast_age(struct dsa_switch *ds, int port, u16
vid)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_vtu_entry vlan;
+	int err;
+
+	mv88e6xxx_reg_lock(chip);
+
+	err = mv88e6xxx_vtu_get(chip, vid, &vlan);
+	if (err)
+		goto unlock;
+
+	err = mv88e6xxx_port_fast_age_fid(chip, port, vlan.fid);
+
+unlock:
+	mv88e6xxx_reg_unlock(chip);
+
+	return err;
+}
+
+static int mv88e6xxx_vlan_msti_set(struct dsa_switch *ds,
+				   struct dsa_bridge bridge,
+				   const struct switchdev_vlan_msti *msti)
+{
+	struct mv88e6xxx_chip *chip = ds->priv;
+	struct mv88e6xxx_vtu_entry vlan;
+	u8 old_sid, new_sid;
+	int err;
+
+	mv88e6xxx_reg_lock(chip);
+
+	err = mv88e6xxx_vtu_get(chip, msti->vid, &vlan);
+	if (err)
+		goto unlock;
+
+	if (!vlan.valid) {
+		err = -EINVAL;
+		goto unlock;
+	}
+
+	old_sid = vlan.sid;
+
+	err = mv88e6xxx_mst_get(chip, bridge.dev, msti->msti, &new_sid);
+	if (err)
+		goto unlock;
+
+	if (new_sid != old_sid) {
+		vlan.sid = new_sid;
+
+		err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
+		if (err) {
+			mv88e6xxx_mst_put(chip, new_sid);
+			goto unlock;
+		}
+	}
+
+	err = mv88e6xxx_mst_put(chip, old_sid);
+
+unlock:
+	mv88e6xxx_reg_unlock(chip);
+	return err;
+}
+
 static int mv88e6xxx_port_fdb_add(struct dsa_switch *ds, int port,
 				  const unsigned char *addr, u16 vid,
 				  struct dsa_db db)
@@ -6008,6 +6238,7 @@ static struct mv88e6xxx_chip *mv88e6xxx_alloc_chip(struct
device *dev)
 	mutex_init(&chip->reg_lock);
 	INIT_LIST_HEAD(&chip->mdios);
 	idr_init(&chip->policies);
+	INIT_LIST_HEAD(&chip->msts);
 
 	return chip;
 }
@@ -6540,10 +6771,13 @@ static const struct dsa_switch_ops mv88e6xxx_switch_ops
= {
 	.port_pre_bridge_flags	= mv88e6xxx_port_pre_bridge_flags,
 	.port_bridge_flags	= mv88e6xxx_port_bridge_flags,
 	.port_stp_state_set	= mv88e6xxx_port_stp_state_set,
+	.port_mst_state_set	= mv88e6xxx_port_mst_state_set,
 	.port_fast_age		= mv88e6xxx_port_fast_age,
+	.port_vlan_fast_age	= mv88e6xxx_port_vlan_fast_age,
 	.port_vlan_filtering	= mv88e6xxx_port_vlan_filtering,
 	.port_vlan_add		= mv88e6xxx_port_vlan_add,
 	.port_vlan_del		= mv88e6xxx_port_vlan_del,
+	.vlan_msti_set		= mv88e6xxx_vlan_msti_set,
 	.port_fdb_add           = mv88e6xxx_port_fdb_add,
 	.port_fdb_del           = mv88e6xxx_port_fdb_del,
 	.port_fdb_dump          = mv88e6xxx_port_fdb_dump,
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 6d4daa24d3e5..6a0b66354e1d 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -297,6 +297,16 @@ struct mv88e6xxx_region_priv {
 	enum mv88e6xxx_region_id id;
 };
 
+struct mv88e6xxx_mst {
+	struct list_head node;
+
+	refcount_t refcnt;
+	struct net_device *br;
+	u16 msti;
+
+	struct mv88e6xxx_stu_entry stu;
+};
+
 struct mv88e6xxx_chip {
 	const struct mv88e6xxx_info *info;
 
@@ -397,6 +407,9 @@ struct mv88e6xxx_chip {
 
 	/* devlink regions */
 	struct devlink_region *regions[_MV88E6XXX_REGION_MAX];
+
+	/* Bridge MST to SID mappings */
+	struct list_head msts;
 };
 
 struct mv88e6xxx_bus_ops {
-- 
2.25.1

On 16/03/2022 17:08, Tobias Waldekranz wrote:
> The bridge has had per-VLAN STP support for a while now, since:
> 
> https://lore.kernel.org/netdev/20200124114022.10883-1-nikolay at
cumulusnetworks.com/
> 
> The current implementation has some problems:
> 
> - The mapping from VLAN to STP state is fixed as 1:1, i.e. each VLAN
>   is managed independently. This is awkward from an MSTP (802.1Q-2018,
>   Clause 13.5) point of view, where the model is that multiple VLANs
>   are grouped into MST instances.
> 
>   Because of the way that the standard is written, presumably, this is
>   also reflected in hardware implementations. It is not uncommon for a
>   switch to support the full 4k range of VIDs, but that the pool of
>   MST instances is much smaller. Some examples:
> 
>   Marvell LinkStreet (mv88e6xxx): 4k VLANs, but only 64 MSTIs
>   Marvell Prestera: 4k VLANs, but only 128 MSTIs
>   Microchip SparX-5i: 4k VLANs, but only 128 MSTIs
> 
> - By default, the feature is enabled, and there is no way to disable
>   it. This makes it hard to add offloading in a backwards compatible
>   way, since any underlying switchdevs have no way to refuse the
>   function if the hardware does not support it
> 
> - The port-global STP state has precedence over per-VLAN states. In
>   MSTP, as far as I understand it, all VLANs will use the common
>   spanning tree (CST) by default - through traffic engineering you can
>   then optimize your network to group subsets of VLANs to use
>   different trees (MSTI). To my understanding, the way this is
>   typically managed in silicon is roughly:
> 
>   Incoming packet:
>   .----.----.--------------.----.-------------
>   | DA | SA | 802.1Q VID=X | ET | Payload ...
>   '----'----'--------------'----'-------------
>                         |
>                         '->|\     .----------------------------.
>                            | +--> | VID | Members | ... | MSTI |
>                    PVID -->|/     |-----|---------|-----|------|
>                                   |   1 | 0001001 | ... |    0 |
>                                   |   2 | 0001010 | ... |   10 |
>                                   |   3 | 0001100 | ... |   10 |
>                                   '----------------------------'
>                                                              |
>                                .-----------------------------'
>                                |  .------------------------.
>                                '->| MSTI | Fwding | Lrning |
>                                   |------|--------|--------|
>                                   |    0 | 111110 | 111110 |
>                                   |   10 | 110111 | 110111 |
>                                   '------------------------'
> 
>   What this is trying to show is that the STP state (whether MSTP is
>   used, or ye olde STP) is always accessed via the VLAN table. If STP
>   is running, all MSTI pointers in that table will reference the same
>   index in the STP stable - if MSTP is running, some VLANs may point
>   to other trees (like in this example).
> 
>   The fact that in the Linux bridge, the global state (think: index 0
>   in most hardware implementations) is supposed to override the
>   per-VLAN state, is very awkward to offload. In effect, this means
>   that when the global state changes to blocking, drivers will have to
>   iterate over all MSTIs in use, and alter them all to match. This
>   also means that you have to cache whether the hardware state is
>   currently tracking the global state or the per-VLAN state. In the
>   first case, you also have to cache the per-VLAN state so that you
>   can restore it if the global state transitions back to forwarding.
> 
> This series adds a new mst_enable bridge setting (as suggested by Nik)
> that can only be changed when no VLANs are configured on the
> bridge. Enabling this mode has the following effect:
> 
> - The port-global STP state is used to represent the CST (Common
>   Spanning Tree) (1/15)
> 
> - Ingress STP filtering is deferred until the frame's VLAN has been
>   resolved (1/15)
> 
> - The preexisting per-VLAN states can no longer be controlled directly
>   (1/15). They are instead placed under the MST module's control,
>   which is managed using a new netlink interface (described in 3/15)
> 
> - VLANs can br mapped to MSTIs in an arbitrary M:N fashion, using a
>   new global VLAN option (2/15)
> 
> Switchdev notifications are added so that a driver can track:
> - MST enabled state
> - VID to MSTI mappings
> - MST port states
> 
> An offloading implementation is this provided for mv88e6xxx.
> 
> A proposal for the corresponding iproute2 interface is available here:
> 
> https://github.com/wkz/iproute2/tree/mst
> 
Hi Tobias,
One major missing thing is the selftests for this new feature. Do you
have a plan to upstream them?

Cheers,
 Nik

Hello:

This series was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba at kernel.org>:

On Wed, 16 Mar 2022 16:08:42 +0100 you wrote:
> The bridge has had per-VLAN STP support for a while now, since:
> 
> https://lore.kernel.org/netdev/20200124114022.10883-1-nikolay at
cumulusnetworks.com/
> 
> The current implementation has some problems:
> 
> - The mapping from VLAN to STP state is fixed as 1:1, i.e. each VLAN
>   is managed independently. This is awkward from an MSTP (802.1Q-2018,
>   Clause 13.5) point of view, where the model is that multiple VLANs
>   are grouped into MST instances.
> 
> [...]
Here is the summary with links:
  - [v5,net-next,01/15] net: bridge: mst: Multiple Spanning Tree (MST) mode
    https://git.kernel.org/netdev/net-next/c/ec7328b59176
  - [v5,net-next,02/15] net: bridge: mst: Allow changing a VLAN's MSTI
    https://git.kernel.org/netdev/net-next/c/8c678d60562f
  - [v5,net-next,03/15] net: bridge: mst: Support setting and reporting MST port
states
    https://git.kernel.org/netdev/net-next/c/122c29486e1f
  - [v5,net-next,04/15] net: bridge: mst: Notify switchdev drivers of MST mode
changes
    https://git.kernel.org/netdev/net-next/c/87c167bb94ee
  - [v5,net-next,05/15] net: bridge: mst: Notify switchdev drivers of VLAN MSTI
migrations
    https://git.kernel.org/netdev/net-next/c/6284c723d9b9
  - [v5,net-next,06/15] net: bridge: mst: Notify switchdev drivers of MST state
changes
    https://git.kernel.org/netdev/net-next/c/7ae9147f4312
  - [v5,net-next,07/15] net: bridge: mst: Add helper to map an MSTI to a VID set
    https://git.kernel.org/netdev/net-next/c/cceac97afa09
  - [v5,net-next,08/15] net: bridge: mst: Add helper to check if MST is enabled
    https://git.kernel.org/netdev/net-next/c/48d57b2e5f43
  - [v5,net-next,09/15] net: bridge: mst: Add helper to query a port's MST
state
    https://git.kernel.org/netdev/net-next/c/f54fd0e16306
  - [v5,net-next,10/15] net: dsa: Validate hardware support for MST
    https://git.kernel.org/netdev/net-next/c/332afc4c8c0d
  - [v5,net-next,11/15] net: dsa: Pass VLAN MSTI migration notifications to
driver
    https://git.kernel.org/netdev/net-next/c/8e6598a7b0fa
  - [v5,net-next,12/15] net: dsa: Handle MST state changes
    https://git.kernel.org/netdev/net-next/c/7414af30b7d8
  - [v5,net-next,13/15] net: dsa: mv88e6xxx: Disentangle STU from VTU
    https://git.kernel.org/netdev/net-next/c/49c98c1dc7d9
  - [v5,net-next,14/15] net: dsa: mv88e6xxx: Export STU as devlink region
    https://git.kernel.org/netdev/net-next/c/7dc96039b967
  - [v5,net-next,15/15] net: dsa: mv88e6xxx: MST Offloading
    https://git.kernel.org/netdev/net-next/c/acaf4d2e36b3

You are awesome, thank you!
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