libnvdimm: Move nvdimm_bus_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
nvdimm_bus_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/157309903815.1582359.6418211876315050283.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 *bus_attr_groups[] = {
-	&nvdimm_bus_attribute_group,
-	NULL,
-};
-
 static inline int papr_scm_node(int node)
 {
 	int min_dist = INT_MAX, dist;
@@ -319,7 +314,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	p->bus_desc.ndctl = papr_scm_ndctl;
 	p->bus_desc.module = THIS_MODULE;
 	p->bus_desc.of_node = p->pdev->dev.of_node;
-	p->bus_desc.attr_groups = bus_attr_groups;
 	p->bus_desc.provider_name = kstrdup(p->pdev->name, GFP_KERNEL);
 
 	if (!p->bus_desc.provider_name)

drivers/acpi/nfit/core.c

@@ -1404,7 +1404,6 @@ static const struct attribute_group acpi_nfit_attribute_group = {
 };
 
 static const struct attribute_group *acpi_nfit_attribute_groups[] = {
-	&nvdimm_bus_attribute_group,
 	&acpi_nfit_attribute_group,
 	NULL,
 };

drivers/nvdimm/bus.c

@@ -300,9 +300,14 @@ static void nvdimm_bus_release(struct device *dev)
 	kfree(nvdimm_bus);
 }
 
+static const struct device_type nvdimm_bus_dev_type = {
+	.release = nvdimm_bus_release,
+	.groups = nvdimm_bus_attribute_groups,
+};
+
 bool is_nvdimm_bus(struct device *dev)
 {
-	return dev->release == nvdimm_bus_release;
+	return dev->type == &nvdimm_bus_dev_type;
 }
 
 struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
@@ -355,7 +360,7 @@ struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
 	badrange_init(&nvdimm_bus->badrange);
 	nvdimm_bus->nd_desc = nd_desc;
 	nvdimm_bus->dev.parent = parent;
-	nvdimm_bus->dev.release = nvdimm_bus_release;
+	nvdimm_bus->dev.type = &nvdimm_bus_dev_type;
 	nvdimm_bus->dev.groups = nd_desc->attr_groups;
 	nvdimm_bus->dev.bus = &nvdimm_bus_type;
 	nvdimm_bus->dev.of_node = nd_desc->of_node;

drivers/nvdimm/core.c

@@ -385,10 +385,14 @@ static struct attribute *nvdimm_bus_attributes[] = {
 	NULL,
 };
 
-struct attribute_group nvdimm_bus_attribute_group = {
+static const struct attribute_group nvdimm_bus_attribute_group = {
 	.attrs = nvdimm_bus_attributes,
 };
-EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);
+
+const struct attribute_group *nvdimm_bus_attribute_groups[] = {
+	&nvdimm_bus_attribute_group,
+	NULL,
+};
 
 int nvdimm_bus_add_badrange(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
 {

drivers/nvdimm/e820.c

@@ -8,11 +8,6 @@
 #include <linux/libnvdimm.h>
 #include <linux/module.h>
 
-static const struct attribute_group *e820_pmem_attribute_groups[] = {
-	&nvdimm_bus_attribute_group,
-	NULL,
-};
-
 static int e820_pmem_remove(struct platform_device *pdev)
 {
 	struct nvdimm_bus *nvdimm_bus = platform_get_drvdata(pdev);
@@ -55,7 +50,6 @@ static int e820_pmem_probe(struct platform_device *pdev)
 	struct nvdimm_bus *nvdimm_bus;
 	int rc = -ENXIO;
 
-	nd_desc.attr_groups = e820_pmem_attribute_groups;
 	nd_desc.provider_name = "e820";
 	nd_desc.module = THIS_MODULE;
 	nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);

drivers/nvdimm/nd.h

@@ -241,6 +241,7 @@ void nd_region_exit(void);
 struct nvdimm;
 extern const struct attribute_group nd_device_attribute_group;
 extern const struct attribute_group nd_numa_attribute_group;
+extern const struct attribute_group *nvdimm_bus_attribute_groups[];
 struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping);
 int nvdimm_check_config_data(struct device *dev);
 int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);

drivers/nvdimm/of_pmem.c

@@ -9,11 +9,6 @@
 #include <linux/ioport.h>
 #include <linux/slab.h>
 
-static const struct attribute_group *bus_attr_groups[] = {
-	&nvdimm_bus_attribute_group,
-	NULL,
-};
-
 struct of_pmem_private {
 	struct nvdimm_bus_descriptor bus_desc;
 	struct nvdimm_bus *bus;
@@ -35,7 +30,6 @@ static int of_pmem_region_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
-	priv->bus_desc.attr_groups = bus_attr_groups;
 	priv->bus_desc.provider_name = kstrdup(pdev->name, GFP_KERNEL);
 	priv->bus_desc.module = THIS_MODULE;
 	priv->bus_desc.of_node = np;

include/linux/libnvdimm.h

@@ -65,8 +65,6 @@ enum {
 	DPA_RESOURCE_ADJUSTED = 1 << 0,
 };
 
-extern struct attribute_group nvdimm_bus_attribute_group;
-
 struct nvdimm;
 struct nvdimm_bus_descriptor;
 typedef int (*ndctl_fn)(struct nvdimm_bus_descriptor *nd_desc,