Merge branch 'mlxsw-enslavement'

Petr Machata says:

====================
mlxsw: Permit enslavement to netdevices with uppers

The mlxsw driver currently makes the assumption that the user applies
configuration in a bottom-up manner. Thus netdevices need to be added to
the bridge before IP addresses are configured on that bridge or SVI added
on top of it. Enslaving a netdevice to another netdevice that already has
uppers is in fact forbidden by mlxsw for this reason. Despite this safety,
it is rather easy to get into situations where the offloaded configuration
is just plain wrong.

As an example, take a front panel port, configure an IP address: it gets a
RIF. Now enslave the port to the bridge, and the RIF is gone. Remove the
port from the bridge again, but the RIF never comes back. There is a number
of similar situations, where changing the configuration there and back
utterly breaks the offload.

Similarly, detaching a front panel port from a configured topology means
unoffloading of this whole topology -- VLAN uppers, next hops, etc.
Attaching the port back is then not permitted at all. If it were, it would
not result in a working configuration, because much of mlxsw is written to
react to changes in immediate configuration. There is nothing that would go
visit netdevices in the attached-to topology and offload existing routes
and VLAN memberships, for example.

In this patchset, introduce a number of replays to be invoked so that this
sort of post-hoc offload is supported. Then remove the vetoes that
disallowed enslavement of front panel ports to other netdevices with
uppers.

The patchset progresses as follows:

- In patch #1, fix an issue in the bridge driver. To my knowledge, the
  issue could not have resulted in a buggy behavior previously, and thus is
  packaged with this patchset instead of being sent separately to net.

- In patch #2, add a new helper to the switchdev code.

- In patch #3, drop mlxsw selftests that will not be relevant after this
  patchset anymore.

- Patches #4, #5, #6, #7 and #8 prepare the codebase for smoother
  introduction of the rest of the code.

- Patches #9, #10, #11, #12, #13 and #14 replay various aspects of upper
  configuration when a front panel port is introduced into a topology.
  Individual patches take care of bridge and LAG RIF memberships, switchdev
  replay, nexthop and neighbors replay, and MACVLAN offload.

- Patches #15 and #16 introduce RIFs for newly-relevant netdevices when a
  front panel port is enslaved (in which case all uppers are newly
  relevant), or, respectively, deslaved (in which case the newly-relevant
  netdevice is the one being deslaved).

- Up until this point, the introduced scaffolding was not really used,
  because mlxsw still forbids enslavement of mlxsw netdevices to uppers
  with uppers. In patch #17, this condition is finally relaxed.

A sizable selftest suite is available to test all this new code. That will
be sent in a separate patchset.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 63 insertions, 1 deletions

diff --git a/net/bridge/br.c b/net/bridge/br.c
index 4f5098d33a46..a6e94ceb7c9a 100644
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -234,6 +234,14 @@ static int br_switchdev_blocking_event(struct notifier_block *nb,
 		br_switchdev_port_unoffload(p, b->ctx, b->atomic_nb,
 					    b->blocking_nb);
 		break;
+	case SWITCHDEV_BRPORT_REPLAY:
+		brport_info = ptr;
+		b = &brport_info->brport;
+
+		err = br_switchdev_port_replay(p, b->dev, b->ctx, b->atomic_nb,
+					       b->blocking_nb, extack);
+		err = notifier_from_errno(err);
+		break;
 	}
 
 out:
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 05a965ef76f1..51e4ca54b537 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -2118,6 +2118,12 @@ void br_switchdev_port_unoffload(struct net_bridge_port *p, const void *ctx,
 				 struct notifier_block *atomic_nb,
 				 struct notifier_block *blocking_nb);
 
+int br_switchdev_port_replay(struct net_bridge_port *p,
+			     struct net_device *dev, const void *ctx,
+			     struct notifier_block *atomic_nb,
+			     struct notifier_block *blocking_nb,
+			     struct netlink_ext_ack *extack);
+
 bool br_switchdev_frame_uses_tx_fwd_offload(struct sk_buff *skb);
 
 void br_switchdev_frame_set_offload_fwd_mark(struct sk_buff *skb);
@@ -2168,6 +2174,16 @@ br_switchdev_port_unoffload(struct net_bridge_port *p, const void *ctx,
 {
 }
 
+static inline int
+br_switchdev_port_replay(struct net_bridge_port *p,
+			 struct net_device *dev, const void *ctx,
+			 struct notifier_block *atomic_nb,
+			 struct notifier_block *blocking_nb,
+			 struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline bool br_switchdev_frame_uses_tx_fwd_offload(struct sk_buff *skb)
 {
 	return false;
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index ba95c4d74a60..ee84e783e1df 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -727,6 +727,8 @@ br_switchdev_mdb_replay(struct net_device *br_dev, struct net_device *dev,
 		err = br_switchdev_mdb_replay_one(nb, dev,
 						  SWITCHDEV_OBJ_PORT_MDB(obj),
 						  action, ctx, extack);
+		if (err == -EOPNOTSUPP)
+			err = 0;
 		if (err)
 			goto out_free_mdb;
 	}
@@ -759,8 +761,10 @@ static int nbp_switchdev_sync_objs(struct net_bridge_port *p, const void *ctx,
 
 	err = br_switchdev_mdb_replay(br_dev, dev, ctx, true, blocking_nb,
 				      extack);
-	if (err && err != -EOPNOTSUPP)
+	if (err) {
+		/* -EOPNOTSUPP not propagated from MDB replay. */
 		return err;
+	}
 
 	err = br_switchdev_fdb_replay(br_dev, ctx, true, atomic_nb);
 	if (err && err != -EOPNOTSUPP)
@@ -825,3 +829,12 @@ void br_switchdev_port_unoffload(struct net_bridge_port *p, const void *ctx,
 
 	nbp_switchdev_del(p);
 }
+
+int br_switchdev_port_replay(struct net_bridge_port *p,
+			     struct net_device *dev, const void *ctx,
+			     struct notifier_block *atomic_nb,
+			     struct notifier_block *blocking_nb,
+			     struct netlink_ext_ack *extack)
+{
+	return nbp_switchdev_sync_objs(p, ctx, atomic_nb, blocking_nb, extack);
+}
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 8cc42aea19c7..5b045284849e 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -862,3 +862,28 @@ void switchdev_bridge_port_unoffload(struct net_device *brport_dev,
 					  NULL);
 }
 EXPORT_SYMBOL_GPL(switchdev_bridge_port_unoffload);
+
+int switchdev_bridge_port_replay(struct net_device *brport_dev,
+				 struct net_device *dev, const void *ctx,
+				 struct notifier_block *atomic_nb,
+				 struct notifier_block *blocking_nb,
+				 struct netlink_ext_ack *extack)
+{
+	struct switchdev_notifier_brport_info brport_info = {
+		.brport = {
+			.dev = dev,
+			.ctx = ctx,
+			.atomic_nb = atomic_nb,
+			.blocking_nb = blocking_nb,
+		},
+	};
+	int err;
+
+	ASSERT_RTNL();
+
+	err = call_switchdev_blocking_notifiers(SWITCHDEV_BRPORT_REPLAY,
+						brport_dev, &brport_info.info,
+						extack);
+	return notifier_to_errno(err);
+}
+EXPORT_SYMBOL_GPL(switchdev_bridge_port_replay);