diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
index e5322f33706e..50cadae20ac9 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
@@ -643,7 +643,7 @@ zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
 {
 	zio_t *zio;
 
-	ASSERT3U(type == ZIO_TYPE_FREE || psize, <=, SPA_MAXBLOCKSIZE);
+	IMPLY(type != ZIO_TYPE_FREE, psize <= SPA_MAXBLOCKSIZE);
 	ASSERT(P2PHASE(psize, SPA_MINBLOCKSIZE) == 0);
 	ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);