diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index f84093b..cae0a85 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -581,7 +581,7 @@
 {
 	int ret;
 
-	switch (arg) {
+	switch (cmd) {
 	case HDIO_GET_UNMASKINTR:
 	case HDIO_GET_MULTCOUNT:
 	case HDIO_GET_KEEPSETTINGS: