diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index c5c45de..7cbbc7a 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -301,6 +301,12 @@
 	u32 data;
 	void __user *dxferp;
 	int err;
+	int interface_id;
+
+	if (get_user(interface_id, &sgio32->interface_id))
+		return -EFAULT;
+	if (interface_id != 'S')
+		return sys_ioctl(fd, cmd, (unsigned long)sgio32);
 
 	if (get_user(iovec_count, &sgio32->iovec_count))
 		return -EFAULT;