diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 72a1784dae54..1f8fddcc34d6 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -48,8 +48,8 @@ static int qxl_alloc_client_monitors_config(struct qxl_device *qdev,
 	}
 	if (!qdev->client_monitors_config) {
 		qdev->client_monitors_config = kzalloc(
-				sizeof(struct qxl_monitors_config) +
-				sizeof(struct qxl_head) * count, GFP_KERNEL);
+				struct_size(qdev->client_monitors_config,
+				heads, count), GFP_KERNEL);
 		if (!qdev->client_monitors_config)
 			return -ENOMEM;
 	}