diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 08b561f0709d..da6568a20177 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -26,7 +26,7 @@ struct gsb_buffer {
 	union {
 		u16	wdata;
 		u8	bdata;
-		u8	data[0];
+		DECLARE_FLEX_ARRAY(u8, data);
 	};
 } __packed;