diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 38f8cae7ef514..17f9ed6888417 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -32,6 +32,7 @@
 #include <linux/of_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/component.h>
+#include <linux/overflow.h>
 
 #include <linux/reset.h>
 #include <linux/delay.h>
@@ -1579,7 +1580,6 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
 	struct drm_device *drm_dev = data;
 	struct vop *vop;
 	struct resource *res;
-	size_t alloc_size;
 	int ret, irq;
 
 	vop_data = of_device_get_match_data(dev);
@@ -1587,8 +1587,8 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
 		return -ENODEV;
 
 	/* Allocate vop struct and its vop_win array */
-	alloc_size = sizeof(*vop) + sizeof(*vop->win) * vop_data->win_size;
-	vop = devm_kzalloc(dev, alloc_size, GFP_KERNEL);
+	vop = devm_kzalloc(dev, struct_size(vop, win, vop_data->win_size),
+			   GFP_KERNEL);
 	if (!vop)
 		return -ENOMEM;