[PATCH net v3 1/2] net/mlx5: Bridge, don't fail switchdev events of sibling eswitch ports

[Bernardo Soares <bsoares.it@gmail.com>]

mlx5 registers the bridge offload switchdev notifiers once per eswitch
instance, but the notifier chains are global, so every instance sees
every event and must filter out the ones that aren't its own. The
existing filter, mlx5_esw_bridge_dev_same_hw(), only checks that the
event netdevice sits on the same HCA - intentional for merged eswitch,
where one bridge can span representors of several eswitches on one
HCA - but same-HCA doesn't mean the instance actually has that port:
peer ports are only created reactively from NETDEV_CHANGEUPPER, so an
instance brought up after a sibling PF's port was already enslaved has
none. The port object and attribute handlers claim the event anyway
once same-HW passes, then fail the port lookup and return -EINVAL,
which gets reported to user space even though the owning instance
already handled it (e.g. "bridge vlan add ... RTNETLINK answers:
Invalid argument"). Fix by filtering on the tracked port instead.

The same gap exists in the LAG bond lookup used by attribute changes
on a bonded uplink: mlx5_esw_bridge_lower_rep_vport_num_vhca_id_get()
walks the bond's lower devices and returns the first rep that's
structurally eligible (same HCA, is a rep), without checking it's
tracked by the calling instance's br_offloads. Lower devices are
appended in enslavement order (__netdev_adjacent_dev_insert() uses
list_add_tail_rcu()), so on a merged-eswitch HCA where a bond spans
reps of more than one eswitch instance, whichever rep was enslaved
first wins the walk regardless of which instance's br_offloads is
doing the lookup. If a sibling's rep was enslaved first, this returns
that rep instead of continuing to the one this instance actually owns
- reached via mlx5_esw_bridge_port_obj_attr_set(), so a bridge
attribute change on a bonded uplink can silently no-op on the right
instance depending on enslavement order. Fix the same way, by checking
mlx5_esw_bridge_port_exists() at the point each rep is picked.

Fixes: c358ea1741bc ("net/mlx5: Bridge, allow merged eswitch connectivity")
Signed-off-by: Bernardo Soares <bsoares.it@gmail.com>
Cc: Vlad Buslov <vladbu@nvidia.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>
---
 .../mellanox/mlx5/core/en/rep/bridge.c        | 45 +++++++++++++++----
 .../ethernet/mellanox/mlx5/core/esw/bridge.c  |  6 +++
 .../ethernet/mellanox/mlx5/core/esw/bridge.h  |  2 +
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c b/drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c
index baac38bece14..4b7b0a0fc2b2 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c
@@ -85,9 +85,16 @@ mlx5_esw_bridge_lower_rep_vport_num_vhca_id_get(struct net_device *dev, struct m
 	struct net_device *lower_dev;
 	struct list_head *iter;
 
-	if (netif_is_lag_master(dev) || mlx5e_eswitch_rep(dev))
-		return mlx5_esw_bridge_rep_vport_num_vhca_id_get(dev, esw, vport_num,
-								 esw_owner_vhca_id);
+	if (netif_is_lag_master(dev) || mlx5e_eswitch_rep(dev)) {
+		struct net_device *rep;
+
+		rep = mlx5_esw_bridge_rep_vport_num_vhca_id_get(dev, esw, vport_num,
+								esw_owner_vhca_id);
+		if (rep && !mlx5_esw_bridge_port_exists(*vport_num, *esw_owner_vhca_id,
+							esw->br_offloads))
+			return NULL;
+		return rep;
+	}
 
 	netdev_for_each_lower_dev(dev, lower_dev, iter) {
 		struct net_device *rep;
@@ -104,6 +111,28 @@ mlx5_esw_bridge_lower_rep_vport_num_vhca_id_get(struct net_device *dev, struct m
 	return NULL;
 }
 
+static bool mlx5_esw_bridge_rep_port_lookup(struct net_device *dev,
+					    struct mlx5_esw_bridge_offloads *br_offloads,
+					    u16 *vport_num, u16 *esw_owner_vhca_id)
+{
+	if (!mlx5_esw_bridge_rep_vport_num_vhca_id_get(dev, br_offloads->esw, vport_num,
+						       esw_owner_vhca_id))
+		return false;
+
+	return mlx5_esw_bridge_port_exists(*vport_num, *esw_owner_vhca_id, br_offloads);
+}
+
+static bool mlx5_esw_bridge_lower_rep_port_lookup(struct net_device *dev,
+						  struct mlx5_esw_bridge_offloads *br_offloads,
+						  u16 *vport_num, u16 *esw_owner_vhca_id)
+{
+	if (!mlx5_esw_bridge_lower_rep_vport_num_vhca_id_get(dev, br_offloads->esw, vport_num,
+							     esw_owner_vhca_id))
+		return false;
+
+	return mlx5_esw_bridge_port_exists(*vport_num, *esw_owner_vhca_id, br_offloads);
+}
+
 static bool mlx5_esw_bridge_is_local(struct net_device *dev, struct net_device *rep,
 				     struct mlx5_eswitch *esw)
 {
@@ -218,8 +247,7 @@ mlx5_esw_bridge_port_obj_add(struct net_device *dev,
 	u16 vport_num, esw_owner_vhca_id;
 	int err;
 
-	if (!mlx5_esw_bridge_rep_vport_num_vhca_id_get(dev, br_offloads->esw, &vport_num,
-						       &esw_owner_vhca_id))
+	if (!mlx5_esw_bridge_rep_port_lookup(dev, br_offloads, &vport_num, &esw_owner_vhca_id))
 		return 0;
 
 	port_obj_info->handled = true;
@@ -251,8 +279,7 @@ mlx5_esw_bridge_port_obj_del(struct net_device *dev,
 	const struct switchdev_obj_port_mdb *mdb;
 	u16 vport_num, esw_owner_vhca_id;
 
-	if (!mlx5_esw_bridge_rep_vport_num_vhca_id_get(dev, br_offloads->esw, &vport_num,
-						       &esw_owner_vhca_id))
+	if (!mlx5_esw_bridge_rep_port_lookup(dev, br_offloads, &vport_num, &esw_owner_vhca_id))
 		return 0;
 
 	port_obj_info->handled = true;
@@ -283,8 +310,8 @@ mlx5_esw_bridge_port_obj_attr_set(struct net_device *dev,
 	u16 vport_num, esw_owner_vhca_id;
 	int err = 0;
 
-	if (!mlx5_esw_bridge_lower_rep_vport_num_vhca_id_get(dev, br_offloads->esw, &vport_num,
-							     &esw_owner_vhca_id))
+	if (!mlx5_esw_bridge_lower_rep_port_lookup(dev, br_offloads, &vport_num,
+						   &esw_owner_vhca_id))
 		return 0;
 
 	port_attr_info->handled = true;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
index 87b5fd349594..ac90ccda1272 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
@@ -1686,6 +1686,12 @@ int mlx5_esw_bridge_vport_peer_unlink(struct net_device *br_netdev, u16 vport_nu
 					    extack);
 }
 
+bool mlx5_esw_bridge_port_exists(u16 vport_num, u16 esw_owner_vhca_id,
+				 struct mlx5_esw_bridge_offloads *br_offloads)
+{
+	return mlx5_esw_bridge_port_lookup(vport_num, esw_owner_vhca_id, br_offloads);
+}
+
 int mlx5_esw_bridge_port_vlan_add(u16 vport_num, u16 esw_owner_vhca_id, u16 vid, u16 flags,
 				  struct mlx5_esw_bridge_offloads *br_offloads,
 				  struct netlink_ext_ack *extack)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.h b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.h
index d6f539161993..a4e59cc21089 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.h
@@ -80,6 +80,8 @@ int mlx5_esw_bridge_vlan_proto_set(u16 vport_num, u16 esw_owner_vhca_id, u16 pro
 				   struct mlx5_esw_bridge_offloads *br_offloads);
 int mlx5_esw_bridge_mcast_set(u16 vport_num, u16 esw_owner_vhca_id, bool enable,
 			      struct mlx5_esw_bridge_offloads *br_offloads);
+bool mlx5_esw_bridge_port_exists(u16 vport_num, u16 esw_owner_vhca_id,
+				 struct mlx5_esw_bridge_offloads *br_offloads);
 int mlx5_esw_bridge_port_vlan_add(u16 vport_num, u16 esw_owner_vhca_id, u16 vid, u16 flags,
 				  struct mlx5_esw_bridge_offloads *br_offloads,
 				  struct netlink_ext_ack *extack);
-- 
2.43.0