net/mlx5: Fix return value from tracer initialization

Check return value of mlx5_fw_tracer_start(), set error path and fix
return value of mlx5_fw_tracer_init() accordingly.

Fixes: c71ad41c ("net/mlx5: FW tracer, events handling")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c

@@ -1019,12 +1019,19 @@ int mlx5_fw_tracer_init(struct mlx5_fw_tracer *tracer)
 	MLX5_NB_INIT(&tracer->nb, fw_tracer_event, DEVICE_TRACER);
 	mlx5_eq_notifier_register(dev, &tracer->nb);
 
-	mlx5_fw_tracer_start(tracer);
-
+	err = mlx5_fw_tracer_start(tracer);
+	if (err) {
+		mlx5_core_warn(dev, "FWTracer: Failed to start tracer %d\n", err);
+		goto err_notifier_unregister;
+	}
 	return 0;
 
+err_notifier_unregister:
+	mlx5_eq_notifier_unregister(dev, &tracer->nb);
+	mlx5_core_destroy_mkey(dev, &tracer->buff.mkey);
 err_dealloc_pd:
 	mlx5_core_dealloc_pd(dev, tracer->buff.pdn);
+	cancel_work_sync(&tracer->read_fw_strings_work);
 	return err;
 }