diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 4575171e5beb..b2590409f25e 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -374,7 +374,7 @@ z2_init(void)
 static void __exit z2_exit(void)
 {
     int i, j;
-    blk_unregister_region(MKDEV(Z2RAM_MAJOR, 0), 256);
+    blk_unregister_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT);
     unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
     del_gendisk(z2ram_gendisk);
     put_disk(z2ram_gendisk);