diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b8224ea..d7ae241 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -712,7 +712,7 @@
 #define BLK_BOUNCE_HIGH		-1ULL
 #endif
 #define BLK_BOUNCE_ANY		(-1ULL)
-#define BLK_BOUNCE_ISA		(ISA_DMA_THRESHOLD)
+#define BLK_BOUNCE_ISA		(DMA_BIT_MASK(24))
 
 /*
  * default timeout for SG_IO if none specified