libnvdimm: Move nd_mapping_attribute_group to device_type

A 'struct device_type' instance can carry default attributes for the
device. Use this facility to remove the export of
nd_mapping_attribute_group and put the responsibility on the core rather
than leaf implementations to define this attribute.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/157309902686.1582359.6749533709859492704.stgit@dwillia2-desk3.amr.corp.intel.com

arch/powerpc/platforms/pseries/papr_scm.c

@@ -284,11 +284,6 @@ int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
 	return 0;
 }
 
-static const struct attribute_group *region_attr_groups[] = {
-	&nd_mapping_attribute_group,
-	NULL,
-};
-
 static const struct attribute_group *bus_attr_groups[] = {
 	&nvdimm_bus_attribute_group,
 	NULL,
@@ -362,7 +357,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	mapping.size = p->blocks * p->block_size; // XXX: potential overflow?
 
 	memset(&ndr_desc, 0, sizeof(ndr_desc));
-	ndr_desc.attr_groups = region_attr_groups;
 	target_nid = dev_to_node(&p->pdev->dev);
 	online_nid = papr_scm_node(target_nid);
 	ndr_desc.numa_node = online_nid;

drivers/acpi/nfit/core.c

@@ -2196,7 +2196,6 @@ static const struct attribute_group acpi_nfit_region_attribute_group = {
 };
 
 static const struct attribute_group *acpi_nfit_region_attribute_groups[] = {
-	&nd_mapping_attribute_group,
 	&acpi_nfit_region_attribute_group,
 	NULL,
 };

drivers/nvdimm/region_devs.c

@@ -751,11 +751,10 @@ static struct attribute *mapping_attributes[] = {
 	NULL,
 };
 
-struct attribute_group nd_mapping_attribute_group = {
+static const struct attribute_group nd_mapping_attribute_group = {
 	.is_visible = mapping_visible,
 	.attrs = mapping_attributes,
 };
-EXPORT_SYMBOL_GPL(nd_mapping_attribute_group);
 
 static const struct attribute_group nd_region_attribute_group = {
 	.attrs = nd_region_attributes,
@@ -766,6 +765,7 @@ static const struct attribute_group *nd_region_attribute_groups[] = {
 	&nd_device_attribute_group,
 	&nd_region_attribute_group,
 	&nd_numa_attribute_group,
+	&nd_mapping_attribute_group,
 	NULL,
 };
 

include/linux/libnvdimm.h

@@ -67,7 +67,6 @@ enum {
 
 extern struct attribute_group nvdimm_bus_attribute_group;
 extern struct attribute_group nvdimm_attribute_group;
-extern struct attribute_group nd_mapping_attribute_group;
 
 struct nvdimm;
 struct nvdimm_bus_descriptor;