diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index e8b9d27dbb3c..ae2078eb6a62 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -422,7 +422,7 @@ struct nd_region {
 	struct nd_interleave_set *nd_set;
 	struct nd_percpu_lane __percpu *lane;
 	int (*flush)(struct nd_region *nd_region, struct bio *bio);
-	struct nd_mapping mapping[];
+	struct nd_mapping mapping[] __counted_by(ndr_mappings);
 };
 
 static inline bool nsl_validate_nlabel(struct nd_region *nd_region,
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index e2f1fb99707f..9e4f7ff024a0 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1028,6 +1028,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 
 	if (!nd_region)
 		return NULL;
+	nd_region->ndr_mappings = ndr_desc->num_mappings;
 	/* CXL pre-assigns memregion ids before creating nvdimm regions */
 	if (test_bit(ND_REGION_CXL, &ndr_desc->flags)) {
 		nd_region->id = ndr_desc->memregion;
@@ -1062,7 +1063,6 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 
 		get_device(&nvdimm->dev);
 	}
-	nd_region->ndr_mappings = ndr_desc->num_mappings;
 	nd_region->provider_data = ndr_desc->provider_data;
 	nd_region->nd_set = ndr_desc->nd_set;
 	nd_region->num_lanes = ndr_desc->num_lanes;