diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 9c59d1ceb5b5..c4adbf98fac7 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -581,7 +581,7 @@ static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
 		devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
 		break;
 	case HMM_DMIRROR_MEMORY_DEVICE_COHERENT:
-		devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ?
+		devmem->pagemap.range.start = (MINOR(mdevice->device.devt) - 2) ?
 							spm_addr_dev0 :
 							spm_addr_dev1;
 		devmem->pagemap.range.end = devmem->pagemap.range.start +