-static DEFINE_MUTEX(block_mutex);
-static DECLARE_BITMAP(dev_use, MMC_NUM_MINORS);
+/*
+ * We've only got one major, so number of mmcblk devices is
+ * limited to 256 / number of minors per device.
+ */
+static int max_devices;
+
+/* 256 minors, so at most 256 separate devices */
+static DECLARE_BITMAP(dev_use, 256);