drivers/nvdimm/region_devs.c - SHIFTPHONES/kernel/common - Gitiles

 /*
  * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  */
 #include <linux/scatterlist.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/sort.h>
 #include <linux/io.h>
 #include "nd-core.h"
 #include "nd.h"

 static DEFINE_IDA(region_ida);

 static void nd_region_release(struct device *dev)
 {
 	struct nd_region *nd_region = to_nd_region(dev);
 	u16 i;

 	for (i = 0; i < nd_region->ndr_mappings; i++) {
 		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 		struct nvdimm *nvdimm = nd_mapping->nvdimm;

 		put_device(&nvdimm->dev);
 	}
 	ida_simple_remove(&region_ida, nd_region->id);
 	kfree(nd_region);
 }

 static struct device_type nd_blk_device_type = {
 	.name = "nd_blk",
 	.release = nd_region_release,
 };

 static struct device_type nd_pmem_device_type = {
 	.name = "nd_pmem",
 	.release = nd_region_release,
 };

 static struct device_type nd_volatile_device_type = {
 	.name = "nd_volatile",
 	.release = nd_region_release,
 };

 bool is_nd_pmem(struct device *dev)
 {
 	return dev ? dev->type == &nd_pmem_device_type : false;
 }

 bool is_nd_blk(struct device *dev)
 {
 	return dev ? dev->type == &nd_blk_device_type : false;
 }

 struct nd_region *to_nd_region(struct device *dev)
 {
 	struct nd_region *nd_region = container_of(dev, struct nd_region, dev);

 	WARN_ON(dev->type->release != nd_region_release);
 	return nd_region;
 }
 EXPORT_SYMBOL_GPL(to_nd_region);

 /**
  * nd_region_to_nstype() - region to an integer namespace type
  * @nd_region: region-device to interrogate
  *
  * This is the 'nstype' attribute of a region as well, an input to the
  * MODALIAS for namespace devices, and bit number for a nvdimm_bus to match
  * namespace devices with namespace drivers.
  */
 int nd_region_to_nstype(struct nd_region *nd_region)
 {
 	if (is_nd_pmem(&nd_region->dev)) {
 		u16 i, alias;

 		for (i = 0, alias = 0; i < nd_region->ndr_mappings; i++) {
 			struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 			struct nvdimm *nvdimm = nd_mapping->nvdimm;

 			if (nvdimm->flags & NDD_ALIASING)
 				alias++;
 		}
 		if (alias)
 			return ND_DEVICE_NAMESPACE_PMEM;
 		else
 			return ND_DEVICE_NAMESPACE_IO;
 	} else if (is_nd_blk(&nd_region->dev)) {
 		return ND_DEVICE_NAMESPACE_BLK;
 	}

 	return 0;
 }

 static ssize_t size_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct nd_region *nd_region = to_nd_region(dev);
 	unsigned long long size = 0;

 	if (is_nd_pmem(dev)) {
 		size = nd_region->ndr_size;
 	} else if (nd_region->ndr_mappings == 1) {
 		struct nd_mapping *nd_mapping = &nd_region->mapping[0];

 		size = nd_mapping->size;
 	}

 	return sprintf(buf, "%llu\n", size);
 }
 static DEVICE_ATTR_RO(size);

 static ssize_t mappings_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct nd_region *nd_region = to_nd_region(dev);

 	return sprintf(buf, "%d\n", nd_region->ndr_mappings);
 }
 static DEVICE_ATTR_RO(mappings);

 static ssize_t nstype_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct nd_region *nd_region = to_nd_region(dev);

 	return sprintf(buf, "%d\n", nd_region_to_nstype(nd_region));
 }
 static DEVICE_ATTR_RO(nstype);

 static ssize_t set_cookie_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct nd_region *nd_region = to_nd_region(dev);
 	struct nd_interleave_set *nd_set = nd_region->nd_set;

 	if (is_nd_pmem(dev) && nd_set)
 		/* pass, should be precluded by region_visible */;
 	else
 		return -ENXIO;

 	return sprintf(buf, "%#llx\n", nd_set->cookie);
 }
 static DEVICE_ATTR_RO(set_cookie);

 static ssize_t init_namespaces_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct nd_region_namespaces *num_ns = dev_get_drvdata(dev);
 	ssize_t rc;

 	nvdimm_bus_lock(dev);
 	if (num_ns)
 		rc = sprintf(buf, "%d/%d\n", num_ns->active, num_ns->count);
 	else
 		rc = -ENXIO;
 	nvdimm_bus_unlock(dev);

 	return rc;
 }
 static DEVICE_ATTR_RO(init_namespaces);

 static struct attribute *nd_region_attributes[] = {
 	&dev_attr_size.attr,
 	&dev_attr_nstype.attr,
 	&dev_attr_mappings.attr,
 	&dev_attr_set_cookie.attr,
 	&dev_attr_init_namespaces.attr,
 	NULL,
 };

 static umode_t region_visible(struct kobject *kobj, struct attribute *a, int n)
 {
 	struct device *dev = container_of(kobj, typeof(*dev), kobj);
 	struct nd_region *nd_region = to_nd_region(dev);
 	struct nd_interleave_set *nd_set = nd_region->nd_set;

 	if (a != &dev_attr_set_cookie.attr)
 		return a->mode;

 	if (is_nd_pmem(dev) && nd_set)
 			return a->mode;

 	return 0;
 }

 struct attribute_group nd_region_attribute_group = {
 	.attrs = nd_region_attributes,
 	.is_visible = region_visible,
 };
 EXPORT_SYMBOL_GPL(nd_region_attribute_group);

 /*
  * Upon successful probe/remove, take/release a reference on the
  * associated interleave set (if present)
  */
 static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
 		struct device *dev, bool probe)
 {
 	if (is_nd_pmem(dev) || is_nd_blk(dev)) {
 		struct nd_region *nd_region = to_nd_region(dev);
 		int i;

 		for (i = 0; i < nd_region->ndr_mappings; i++) {
 			struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 			struct nvdimm *nvdimm = nd_mapping->nvdimm;

 			if (probe)
 				atomic_inc(&nvdimm->busy);
 			else
 				atomic_dec(&nvdimm->busy);
 		}
 	}
 }

 void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)
 {
 	nd_region_notify_driver_action(nvdimm_bus, dev, true);
 }

 void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev)
 {
 	nd_region_notify_driver_action(nvdimm_bus, dev, false);
 }

 static ssize_t mappingN(struct device *dev, char *buf, int n)
 {
 	struct nd_region *nd_region = to_nd_region(dev);
 	struct nd_mapping *nd_mapping;
 	struct nvdimm *nvdimm;

 	if (n >= nd_region->ndr_mappings)
 		return -ENXIO;
 	nd_mapping = &nd_region->mapping[n];
 	nvdimm = nd_mapping->nvdimm;

 	return sprintf(buf, "%s,%llu,%llu\n", dev_name(&nvdimm->dev),
 			nd_mapping->start, nd_mapping->size);
 }

 #define REGION_MAPPING(idx) \
 static ssize_t mapping##idx##_show(struct device *dev,		\
 		struct device_attribute *attr, char *buf)	\
 {								\
 	return mappingN(dev, buf, idx);				\
 }								\
 static DEVICE_ATTR_RO(mapping##idx)

 /*
  * 32 should be enough for a while, even in the presence of socket
  * interleave a 32-way interleave set is a degenerate case.
  */
 REGION_MAPPING(0);
 REGION_MAPPING(1);
 REGION_MAPPING(2);
 REGION_MAPPING(3);
 REGION_MAPPING(4);
 REGION_MAPPING(5);
 REGION_MAPPING(6);
 REGION_MAPPING(7);
 REGION_MAPPING(8);
 REGION_MAPPING(9);
 REGION_MAPPING(10);
 REGION_MAPPING(11);
 REGION_MAPPING(12);
 REGION_MAPPING(13);
 REGION_MAPPING(14);
 REGION_MAPPING(15);
 REGION_MAPPING(16);
 REGION_MAPPING(17);
 REGION_MAPPING(18);
 REGION_MAPPING(19);
 REGION_MAPPING(20);
 REGION_MAPPING(21);
 REGION_MAPPING(22);
 REGION_MAPPING(23);
 REGION_MAPPING(24);
 REGION_MAPPING(25);
 REGION_MAPPING(26);
 REGION_MAPPING(27);
 REGION_MAPPING(28);
 REGION_MAPPING(29);
 REGION_MAPPING(30);
 REGION_MAPPING(31);

 static umode_t mapping_visible(struct kobject *kobj, struct attribute *a, int n)
 {
 	struct device *dev = container_of(kobj, struct device, kobj);
 	struct nd_region *nd_region = to_nd_region(dev);

 	if (n < nd_region->ndr_mappings)
 		return a->mode;
 	return 0;
 }

 static struct attribute *mapping_attributes[] = {
 	&dev_attr_mapping0.attr,
 	&dev_attr_mapping1.attr,
 	&dev_attr_mapping2.attr,
 	&dev_attr_mapping3.attr,
 	&dev_attr_mapping4.attr,
 	&dev_attr_mapping5.attr,
 	&dev_attr_mapping6.attr,
 	&dev_attr_mapping7.attr,
 	&dev_attr_mapping8.attr,
 	&dev_attr_mapping9.attr,
 	&dev_attr_mapping10.attr,
 	&dev_attr_mapping11.attr,
 	&dev_attr_mapping12.attr,
 	&dev_attr_mapping13.attr,
 	&dev_attr_mapping14.attr,
 	&dev_attr_mapping15.attr,
 	&dev_attr_mapping16.attr,
 	&dev_attr_mapping17.attr,
 	&dev_attr_mapping18.attr,
 	&dev_attr_mapping19.attr,
 	&dev_attr_mapping20.attr,
 	&dev_attr_mapping21.attr,
 	&dev_attr_mapping22.attr,
 	&dev_attr_mapping23.attr,
 	&dev_attr_mapping24.attr,
 	&dev_attr_mapping25.attr,
 	&dev_attr_mapping26.attr,
 	&dev_attr_mapping27.attr,
 	&dev_attr_mapping28.attr,
 	&dev_attr_mapping29.attr,
 	&dev_attr_mapping30.attr,
 	&dev_attr_mapping31.attr,
 	NULL,
 };

 struct attribute_group nd_mapping_attribute_group = {
 	.is_visible = mapping_visible,
 	.attrs = mapping_attributes,
 };
 EXPORT_SYMBOL_GPL(nd_mapping_attribute_group);

 void *nd_region_provider_data(struct nd_region *nd_region)
 {
 	return nd_region->provider_data;
 }
 EXPORT_SYMBOL_GPL(nd_region_provider_data);

 static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 		struct nd_region_desc *ndr_desc, struct device_type *dev_type,
 		const char *caller)
 {
 	struct nd_region *nd_region;
 	struct device *dev;
 	u16 i;

 	for (i = 0; i < ndr_desc->num_mappings; i++) {
 		struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
 		struct nvdimm *nvdimm = nd_mapping->nvdimm;

 		if ((nd_mapping->start | nd_mapping->size) % SZ_4K) {
 			dev_err(&nvdimm_bus->dev, "%s: %s mapping%d is not 4K aligned\n",
 					caller, dev_name(&nvdimm->dev), i);

 			return NULL;
 		}
 	}

 	nd_region = kzalloc(sizeof(struct nd_region)
 			+ sizeof(struct nd_mapping) * ndr_desc->num_mappings,
 			GFP_KERNEL);
 	if (!nd_region)
 		return NULL;
 	nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
 	if (nd_region->id < 0) {
 		kfree(nd_region);
 		return NULL;
 	}

 	memcpy(nd_region->mapping, ndr_desc->nd_mapping,
 			sizeof(struct nd_mapping) * ndr_desc->num_mappings);
 	for (i = 0; i < ndr_desc->num_mappings; i++) {
 		struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
 		struct nvdimm *nvdimm = nd_mapping->nvdimm;

 		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;
 	dev = &nd_region->dev;
 	dev_set_name(dev, "region%d", nd_region->id);
 	dev->parent = &nvdimm_bus->dev;
 	dev->type = dev_type;
 	dev->groups = ndr_desc->attr_groups;
 	nd_region->ndr_size = resource_size(ndr_desc->res);
 	nd_region->ndr_start = ndr_desc->res->start;
 	nd_device_register(dev);

 	return nd_region;
 }

 struct nd_region *nvdimm_pmem_region_create(struct nvdimm_bus *nvdimm_bus,
 		struct nd_region_desc *ndr_desc)
 {
 	return nd_region_create(nvdimm_bus, ndr_desc, &nd_pmem_device_type,
 			__func__);
 }
 EXPORT_SYMBOL_GPL(nvdimm_pmem_region_create);

 struct nd_region *nvdimm_blk_region_create(struct nvdimm_bus *nvdimm_bus,
 		struct nd_region_desc *ndr_desc)
 {
 	if (ndr_desc->num_mappings > 1)
 		return NULL;
 	return nd_region_create(nvdimm_bus, ndr_desc, &nd_blk_device_type,
 			__func__);
 }
 EXPORT_SYMBOL_GPL(nvdimm_blk_region_create);

 struct nd_region *nvdimm_volatile_region_create(struct nvdimm_bus *nvdimm_bus,
 		struct nd_region_desc *ndr_desc)
 {
 	return nd_region_create(nvdimm_bus, ndr_desc, &nd_volatile_device_type,
 			__func__);
 }
 EXPORT_SYMBOL_GPL(nvdimm_volatile_region_create);
	/*
	* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of version 2 of the GNU General Public License as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*/
	#include <linux/scatterlist.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/sort.h>
	#include <linux/io.h>
	#include "nd-core.h"
	#include "nd.h"

	static DEFINE_IDA(region_ida);

	static void nd_region_release(struct device *dev)
	{
	struct nd_region *nd_region = to_nd_region(dev);
	u16 i;

	for (i = 0; i < nd_region->ndr_mappings; i++) {
	struct nd_mapping *nd_mapping = &nd_region->mapping[i];
	struct nvdimm *nvdimm = nd_mapping->nvdimm;

	put_device(&nvdimm->dev);
	}
	ida_simple_remove(&region_ida, nd_region->id);
	kfree(nd_region);
	}

	static struct device_type nd_blk_device_type = {
	.name = "nd_blk",
	.release = nd_region_release,
	};

	static struct device_type nd_pmem_device_type = {
	.name = "nd_pmem",
	.release = nd_region_release,
	};

	static struct device_type nd_volatile_device_type = {
	.name = "nd_volatile",
	.release = nd_region_release,
	};

	bool is_nd_pmem(struct device *dev)
	{
	return dev ? dev->type == &nd_pmem_device_type : false;
	}

	bool is_nd_blk(struct device *dev)
	{
	return dev ? dev->type == &nd_blk_device_type : false;
	}

	struct nd_region to_nd_region(struct device dev)
	{
	struct nd_region *nd_region = container_of(dev, struct nd_region, dev);

	WARN_ON(dev->type->release != nd_region_release);
	return nd_region;
	}
	EXPORT_SYMBOL_GPL(to_nd_region);

	/**
	* nd_region_to_nstype() - region to an integer namespace type
	* @nd_region: region-device to interrogate
	*
	* This is the 'nstype' attribute of a region as well, an input to the
	* MODALIAS for namespace devices, and bit number for a nvdimm_bus to match
	* namespace devices with namespace drivers.
	*/
	int nd_region_to_nstype(struct nd_region *nd_region)
	{
	if (is_nd_pmem(&nd_region->dev)) {
	u16 i, alias;

	for (i = 0, alias = 0; i < nd_region->ndr_mappings; i++) {
	struct nd_mapping *nd_mapping = &nd_region->mapping[i];
	struct nvdimm *nvdimm = nd_mapping->nvdimm;

	if (nvdimm->flags & NDD_ALIASING)
	alias++;
	}
	if (alias)
	return ND_DEVICE_NAMESPACE_PMEM;
	else
	return ND_DEVICE_NAMESPACE_IO;
	} else if (is_nd_blk(&nd_region->dev)) {
	return ND_DEVICE_NAMESPACE_BLK;
	}

	return 0;
	}

	static ssize_t size_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct nd_region *nd_region = to_nd_region(dev);
	unsigned long long size = 0;

	if (is_nd_pmem(dev)) {
	size = nd_region->ndr_size;
	} else if (nd_region->ndr_mappings == 1) {
	struct nd_mapping *nd_mapping = &nd_region->mapping[0];

	size = nd_mapping->size;
	}

	return sprintf(buf, "%llu\n", size);
	}
	static DEVICE_ATTR_RO(size);

	static ssize_t mappings_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct nd_region *nd_region = to_nd_region(dev);

	return sprintf(buf, "%d\n", nd_region->ndr_mappings);
	}
	static DEVICE_ATTR_RO(mappings);

	static ssize_t nstype_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct nd_region *nd_region = to_nd_region(dev);

	return sprintf(buf, "%d\n", nd_region_to_nstype(nd_region));
	}
	static DEVICE_ATTR_RO(nstype);

	static ssize_t set_cookie_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct nd_region *nd_region = to_nd_region(dev);
	struct nd_interleave_set *nd_set = nd_region->nd_set;

	if (is_nd_pmem(dev) && nd_set)
	/* pass, should be precluded by region_visible */;
	else
	return -ENXIO;

	return sprintf(buf, "%#llx\n", nd_set->cookie);
	}
	static DEVICE_ATTR_RO(set_cookie);

	static ssize_t init_namespaces_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct nd_region_namespaces *num_ns = dev_get_drvdata(dev);
	ssize_t rc;

	nvdimm_bus_lock(dev);
	if (num_ns)
	rc = sprintf(buf, "%d/%d\n", num_ns->active, num_ns->count);
	else
	rc = -ENXIO;
	nvdimm_bus_unlock(dev);

	return rc;
	}
	static DEVICE_ATTR_RO(init_namespaces);

	static struct attribute *nd_region_attributes[] = {
	&dev_attr_size.attr,
	&dev_attr_nstype.attr,
	&dev_attr_mappings.attr,
	&dev_attr_set_cookie.attr,
	&dev_attr_init_namespaces.attr,
	NULL,
	};

	static umode_t region_visible(struct kobject kobj, struct attribute a, int n)
	{
	struct device dev = container_of(kobj, typeof(dev), kobj);
	struct nd_region *nd_region = to_nd_region(dev);
	struct nd_interleave_set *nd_set = nd_region->nd_set;

	if (a != &dev_attr_set_cookie.attr)
	return a->mode;

	if (is_nd_pmem(dev) && nd_set)
	return a->mode;

	return 0;
	}

	struct attribute_group nd_region_attribute_group = {
	.attrs = nd_region_attributes,
	.is_visible = region_visible,
	};
	EXPORT_SYMBOL_GPL(nd_region_attribute_group);

	/*
	* Upon successful probe/remove, take/release a reference on the
	* associated interleave set (if present)
	*/
	static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
	struct device *dev, bool probe)
	{
	if (is_nd_pmem(dev) \|\| is_nd_blk(dev)) {
	struct nd_region *nd_region = to_nd_region(dev);
	int i;

	for (i = 0; i < nd_region->ndr_mappings; i++) {
	struct nd_mapping *nd_mapping = &nd_region->mapping[i];
	struct nvdimm *nvdimm = nd_mapping->nvdimm;

	if (probe)
	atomic_inc(&nvdimm->busy);
	else
	atomic_dec(&nvdimm->busy);
	}
	}
	}

	void nd_region_probe_success(struct nvdimm_bus nvdimm_bus, struct device dev)
	{
	nd_region_notify_driver_action(nvdimm_bus, dev, true);
	}

	void nd_region_disable(struct nvdimm_bus nvdimm_bus, struct device dev)
	{
	nd_region_notify_driver_action(nvdimm_bus, dev, false);
	}

	static ssize_t mappingN(struct device dev, char buf, int n)
	{
	struct nd_region *nd_region = to_nd_region(dev);
	struct nd_mapping *nd_mapping;
	struct nvdimm *nvdimm;

	if (n >= nd_region->ndr_mappings)
	return -ENXIO;
	nd_mapping = &nd_region->mapping[n];
	nvdimm = nd_mapping->nvdimm;

	return sprintf(buf, "%s,%llu,%llu\n", dev_name(&nvdimm->dev),
	nd_mapping->start, nd_mapping->size);
	}

	#define REGION_MAPPING(idx) \
	static ssize_t mapping##idx##_show(struct device *dev, \
	struct device_attribute attr, char buf) \
	{ \
	return mappingN(dev, buf, idx); \
	} \
	static DEVICE_ATTR_RO(mapping##idx)

	/*
	* 32 should be enough for a while, even in the presence of socket
	* interleave a 32-way interleave set is a degenerate case.
	*/
	REGION_MAPPING(0);
	REGION_MAPPING(1);
	REGION_MAPPING(2);
	REGION_MAPPING(3);
	REGION_MAPPING(4);
	REGION_MAPPING(5);
	REGION_MAPPING(6);
	REGION_MAPPING(7);
	REGION_MAPPING(8);
	REGION_MAPPING(9);
	REGION_MAPPING(10);
	REGION_MAPPING(11);
	REGION_MAPPING(12);
	REGION_MAPPING(13);
	REGION_MAPPING(14);
	REGION_MAPPING(15);
	REGION_MAPPING(16);
	REGION_MAPPING(17);
	REGION_MAPPING(18);
	REGION_MAPPING(19);
	REGION_MAPPING(20);
	REGION_MAPPING(21);
	REGION_MAPPING(22);
	REGION_MAPPING(23);
	REGION_MAPPING(24);
	REGION_MAPPING(25);
	REGION_MAPPING(26);
	REGION_MAPPING(27);
	REGION_MAPPING(28);
	REGION_MAPPING(29);
	REGION_MAPPING(30);
	REGION_MAPPING(31);

	static umode_t mapping_visible(struct kobject kobj, struct attribute a, int n)
	{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct nd_region *nd_region = to_nd_region(dev);

	if (n < nd_region->ndr_mappings)
	return a->mode;
	return 0;
	}

	static struct attribute *mapping_attributes[] = {
	&dev_attr_mapping0.attr,
	&dev_attr_mapping1.attr,
	&dev_attr_mapping2.attr,
	&dev_attr_mapping3.attr,
	&dev_attr_mapping4.attr,
	&dev_attr_mapping5.attr,
	&dev_attr_mapping6.attr,
	&dev_attr_mapping7.attr,
	&dev_attr_mapping8.attr,
	&dev_attr_mapping9.attr,
	&dev_attr_mapping10.attr,
	&dev_attr_mapping11.attr,
	&dev_attr_mapping12.attr,
	&dev_attr_mapping13.attr,
	&dev_attr_mapping14.attr,
	&dev_attr_mapping15.attr,
	&dev_attr_mapping16.attr,
	&dev_attr_mapping17.attr,
	&dev_attr_mapping18.attr,
	&dev_attr_mapping19.attr,
	&dev_attr_mapping20.attr,
	&dev_attr_mapping21.attr,
	&dev_attr_mapping22.attr,
	&dev_attr_mapping23.attr,
	&dev_attr_mapping24.attr,
	&dev_attr_mapping25.attr,
	&dev_attr_mapping26.attr,
	&dev_attr_mapping27.attr,
	&dev_attr_mapping28.attr,
	&dev_attr_mapping29.attr,
	&dev_attr_mapping30.attr,
	&dev_attr_mapping31.attr,
	NULL,
	};

	struct attribute_group nd_mapping_attribute_group = {
	.is_visible = mapping_visible,
	.attrs = mapping_attributes,
	};
	EXPORT_SYMBOL_GPL(nd_mapping_attribute_group);

	void nd_region_provider_data(struct nd_region nd_region)
	{
	return nd_region->provider_data;
	}
	EXPORT_SYMBOL_GPL(nd_region_provider_data);

	static struct nd_region nd_region_create(struct nvdimm_bus nvdimm_bus,
	struct nd_region_desc ndr_desc, struct device_type dev_type,
	const char *caller)
	{
	struct nd_region *nd_region;
	struct device *dev;
	u16 i;

	for (i = 0; i < ndr_desc->num_mappings; i++) {
	struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
	struct nvdimm *nvdimm = nd_mapping->nvdimm;

	if ((nd_mapping->start \| nd_mapping->size) % SZ_4K) {
	dev_err(&nvdimm_bus->dev, "%s: %s mapping%d is not 4K aligned\n",
	caller, dev_name(&nvdimm->dev), i);

	return NULL;
	}
	}

	nd_region = kzalloc(sizeof(struct nd_region)
	+ sizeof(struct nd_mapping) * ndr_desc->num_mappings,
	GFP_KERNEL);
	if (!nd_region)
	return NULL;
	nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
	if (nd_region->id < 0) {
	kfree(nd_region);
	return NULL;
	}

	memcpy(nd_region->mapping, ndr_desc->nd_mapping,
	sizeof(struct nd_mapping) * ndr_desc->num_mappings);
	for (i = 0; i < ndr_desc->num_mappings; i++) {
	struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
	struct nvdimm *nvdimm = nd_mapping->nvdimm;

	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;
	dev = &nd_region->dev;
	dev_set_name(dev, "region%d", nd_region->id);
	dev->parent = &nvdimm_bus->dev;
	dev->type = dev_type;
	dev->groups = ndr_desc->attr_groups;
	nd_region->ndr_size = resource_size(ndr_desc->res);
	nd_region->ndr_start = ndr_desc->res->start;
	nd_device_register(dev);

	return nd_region;
	}

	struct nd_region nvdimm_pmem_region_create(struct nvdimm_bus nvdimm_bus,
	struct nd_region_desc *ndr_desc)
	{
	return nd_region_create(nvdimm_bus, ndr_desc, &nd_pmem_device_type,
	__func__);
	}
	EXPORT_SYMBOL_GPL(nvdimm_pmem_region_create);

	struct nd_region nvdimm_blk_region_create(struct nvdimm_bus nvdimm_bus,
	struct nd_region_desc *ndr_desc)
	{
	if (ndr_desc->num_mappings > 1)
	return NULL;
	return nd_region_create(nvdimm_bus, ndr_desc, &nd_blk_device_type,
	__func__);
	}
	EXPORT_SYMBOL_GPL(nvdimm_blk_region_create);

	struct nd_region nvdimm_volatile_region_create(struct nvdimm_bus nvdimm_bus,
	struct nd_region_desc *ndr_desc)
	{
	return nd_region_create(nvdimm_bus, ndr_desc, &nd_volatile_device_type,
	__func__);
	}
	EXPORT_SYMBOL_GPL(nvdimm_volatile_region_create);