net/mlx5: E-switch, Devcom, sync devcom events and devcom comp register

devcom events are sent to all registered component. Following the
cited patch, it is possible for two components, e.g.: two eswitches,
to send devcom events, while both components are registered. This
means eswitch layer will do double un/pairing, which is double
allocation and free of resources, even though only one un/pairing is
needed. flow example:

	cpu0					cpu1
	----					----

 mlx5_devlink_eswitch_mode_set(dev0)
  esw_offloads_devcom_init()
   mlx5_devcom_register_component(esw0)
                                         mlx5_devlink_eswitch_mode_set(dev1)
                                          esw_offloads_devcom_init()
                                           mlx5_devcom_register_component(esw1)
                                           mlx5_devcom_send_event()
   mlx5_devcom_send_event()

Hence, check whether the eswitches are already un/paired before
free/allocation of resources.

Fixes: 09b2784 ("net: devlink: enable parallel ops on netlink interface")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/eswitch.h

@@ -342,6 +342,7 @@ struct mlx5_eswitch {
 		u32             large_group_num;
 	}  params;
 	struct blocking_notifier_head n_head;
+	bool paired[MLX5_MAX_PORTS];
 };
 
 void esw_offloads_disable(struct mlx5_eswitch *esw);

drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c

@@ -2742,6 +2742,9 @@ static int mlx5_esw_offloads_devcom_event(int event,
 		    mlx5_eswitch_vport_match_metadata_enabled(peer_esw))
 			break;
 
+		if (esw->paired[mlx5_get_dev_index(peer_esw->dev)])
+			break;
+
 		err = mlx5_esw_offloads_set_ns_peer(esw, peer_esw, true);
 		if (err)
 			goto err_out;
@@ -2753,14 +2756,18 @@ static int mlx5_esw_offloads_devcom_event(int event,
 		if (err)
 			goto err_pair;
 
+		esw->paired[mlx5_get_dev_index(peer_esw->dev)] = true;
+		peer_esw->paired[mlx5_get_dev_index(esw->dev)] = true;
 		mlx5_devcom_set_paired(devcom, MLX5_DEVCOM_ESW_OFFLOADS, true);
 		break;
 
 	case ESW_OFFLOADS_DEVCOM_UNPAIR:
-		if (!mlx5_devcom_is_paired(devcom, MLX5_DEVCOM_ESW_OFFLOADS))
+		if (!esw->paired[mlx5_get_dev_index(peer_esw->dev)])
 			break;
 
 		mlx5_devcom_set_paired(devcom, MLX5_DEVCOM_ESW_OFFLOADS, false);
+		esw->paired[mlx5_get_dev_index(peer_esw->dev)] = false;
+		peer_esw->paired[mlx5_get_dev_index(esw->dev)] = false;
 		mlx5_esw_offloads_unpair(peer_esw);
 		mlx5_esw_offloads_unpair(esw);
 		mlx5_esw_offloads_set_ns_peer(esw, peer_esw, false);