diff --git a/sys/dev/mana/gdma_main.c b/sys/dev/mana/gdma_main.c
--- a/sys/dev/mana/gdma_main.c
+++ b/sys/dev/mana/gdma_main.c
@@ -221,7 +221,7 @@
 	if (!gc || !gmi)
 		return EINVAL;
 
-	if (length < PAGE_SIZE || (length != roundup_pow_of_two(length)))
+	if (length < PAGE_SIZE || !powerof2(length))
 		return EINVAL;
 
 	err = bus_dma_tag_create(bus_get_dma_tag(gc->dev),	/* parent */