diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index dd9f2d765e68b27fbc016f2c34571dff8c94c500..00abe0e5d602bc8d51545aae2bc3c60c6f0c9f4f 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -463,7 +463,8 @@ struct fw_iso_packet {
 	u32 tag:2;		/* tx: Tag in packet header		*/
 	u32 sy:4;		/* tx: Sy in packet header		*/
 	u32 header_length:8;	/* Length of immediate header		*/
-	u32 header[];		/* tx: Top of 1394 isoch. data_block	*/
+				/* tx: Top of 1394 isoch. data_block    */
+	u32 header[] __counted_by(header_length);
 };
 
 #define FW_ISO_CONTEXT_TRANSMIT			0