diff --git a/drivers/mtd/nand/raw/jz4780_nand.c b/drivers/mtd/nand/raw/jz4780_nand.c
index db4fa60bd52a..ac6239588f26 100644
--- a/drivers/mtd/nand/raw/jz4780_nand.c
+++ b/drivers/mtd/nand/raw/jz4780_nand.c
@@ -352,7 +352,7 @@ static int jz4780_nand_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
+	nfc = devm_kzalloc(dev, struct_size(nfc, cs, num_banks), GFP_KERNEL);
 	if (!nfc)
 		return -ENOMEM;