drivers/nvdimm/pmem.c - kernel/msm-4.19 - Gitiles

 /*
  * Persistent Memory Driver
  *
  * Copyright (c) 2014-2015, Intel Corporation.
  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope 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 <asm/cacheflush.h>
 #include <linux/blkdev.h>
 #include <linux/hdreg.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/badblocks.h>
 #include <linux/memremap.h>
 #include <linux/vmalloc.h>
 #include <linux/pfn_t.h>
 #include <linux/slab.h>
 #include <linux/pmem.h>
 #include <linux/nd.h>
 #include "pmem.h"
 #include "pfn.h"
 #include "nd.h"

 static struct device *to_dev(struct pmem_device *pmem)
 {
 	/*
 	 * nvdimm bus services need a 'dev' parameter, and we record the device
 	 * at init in bb.dev.
 	 */
 	return pmem->bb.dev;
 }

 static struct nd_region *to_region(struct pmem_device *pmem)
 {
 	return to_nd_region(to_dev(pmem)->parent);
 }

 static int pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
 		unsigned int len)
 {
 	struct device *dev = to_dev(pmem);
 	sector_t sector;
 	long cleared;
 	int rc = 0;

 	sector = (offset - pmem->data_offset) / 512;

 	cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
 	if (cleared < len)
 		rc = -EIO;
 	if (cleared > 0 && cleared / 512) {
 		cleared /= 512;
 		dev_dbg(dev, "%s: %#llx clear %ld sector%s\n", __func__,
 				(unsigned long long) sector, cleared,
 				cleared > 1 ? "s" : "");
 		badblocks_clear(&pmem->bb, sector, cleared);
 	}

 	invalidate_pmem(pmem->virt_addr + offset, len);

 	return rc;
 }

 static void write_pmem(void *pmem_addr, struct page *page,
 		unsigned int off, unsigned int len)
 {
 	void *mem = kmap_atomic(page);

 	memcpy_to_pmem(pmem_addr, mem + off, len);
 	kunmap_atomic(mem);
 }

 static int read_pmem(struct page *page, unsigned int off,
 		void *pmem_addr, unsigned int len)
 {
 	int rc;
 	void *mem = kmap_atomic(page);

 	rc = memcpy_from_pmem(mem + off, pmem_addr, len);
 	kunmap_atomic(mem);
 	return rc;
 }

 static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 			unsigned int len, unsigned int off, bool is_write,
 			sector_t sector)
 {
 	int rc = 0;
 	bool bad_pmem = false;
 	phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
 	void *pmem_addr = pmem->virt_addr + pmem_off;

 	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
 		bad_pmem = true;

 	if (!is_write) {
 		if (unlikely(bad_pmem))
 			rc = -EIO;
 		else {
 			rc = read_pmem(page, off, pmem_addr, len);
 			flush_dcache_page(page);
 		}
 	} else {
 		/*
 		 * Note that we write the data both before and after
 		 * clearing poison.  The write before clear poison
 		 * handles situations where the latest written data is
 		 * preserved and the clear poison operation simply marks
 		 * the address range as valid without changing the data.
 		 * In this case application software can assume that an
 		 * interrupted write will either return the new good
 		 * data or an error.
 		 *
 		 * However, if pmem_clear_poison() leaves the data in an
 		 * indeterminate state we need to perform the write
 		 * after clear poison.
 		 */
 		flush_dcache_page(page);
 		write_pmem(pmem_addr, page, off, len);
 		if (unlikely(bad_pmem)) {
 			rc = pmem_clear_poison(pmem, pmem_off, len);
 			write_pmem(pmem_addr, page, off, len);
 		}
 	}

 	return rc;
 }

 /* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */
 #ifndef REQ_FLUSH
 #define REQ_FLUSH REQ_PREFLUSH
 #endif

 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 {
 	int rc = 0;
 	bool do_acct;
 	unsigned long start;
 	struct bio_vec bvec;
 	struct bvec_iter iter;
 	struct pmem_device *pmem = q->queuedata;
 	struct nd_region *nd_region = to_region(pmem);

 	if (bio->bi_opf & REQ_FLUSH)
 		nvdimm_flush(nd_region);

 	do_acct = nd_iostat_start(bio, &start);
 	bio_for_each_segment(bvec, bio, iter) {
 		rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
 				bvec.bv_offset, op_is_write(bio_op(bio)),
 				iter.bi_sector);
 		if (rc) {
 			bio->bi_error = rc;
 			break;
 		}
 	}
 	if (do_acct)
 		nd_iostat_end(bio, start);

 	if (bio->bi_opf & REQ_FUA)
 		nvdimm_flush(nd_region);

 	bio_endio(bio);
 	return BLK_QC_T_NONE;
 }

 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 		       struct page *page, bool is_write)
 {
 	struct pmem_device *pmem = bdev->bd_queue->queuedata;
 	int rc;

 	rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, is_write, sector);

 	/*
 	 * The ->rw_page interface is subtle and tricky.  The core
 	 * retries on any error, so we can only invoke page_endio() in
 	 * the successful completion case.  Otherwise, we'll see crashes
 	 * caused by double completion.
 	 */
 	if (rc == 0)
 		page_endio(page, is_write, 0);

 	return rc;
 }

 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
 __weak long pmem_direct_access(struct block_device *bdev, sector_t sector,
 		      void **kaddr, pfn_t *pfn, long size)
 {
 	struct pmem_device *pmem = bdev->bd_queue->queuedata;
 	resource_size_t offset = sector * 512 + pmem->data_offset;

 	if (unlikely(is_bad_pmem(&pmem->bb, sector, size)))
 		return -EIO;
 	*kaddr = pmem->virt_addr + offset;
 	*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);

 	/*
 	 * If badblocks are present, limit known good range to the
 	 * requested range.
 	 */
 	if (unlikely(pmem->bb.count))
 		return size;
 	return pmem->size - pmem->pfn_pad - offset;
 }

 static const struct block_device_operations pmem_fops = {
 	.owner =		THIS_MODULE,
 	.rw_page =		pmem_rw_page,
 	.direct_access =	pmem_direct_access,
 	.revalidate_disk =	nvdimm_revalidate_disk,
 };

 static void pmem_release_queue(void *q)
 {
 	blk_cleanup_queue(q);
 }

 static void pmem_release_disk(void *disk)
 {
 	del_gendisk(disk);
 	put_disk(disk);
 }

 static int pmem_attach_disk(struct device *dev,
 		struct nd_namespace_common *ndns)
 {
 	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 	struct nd_region *nd_region = to_nd_region(dev->parent);
 	struct vmem_altmap __altmap, *altmap = NULL;
 	struct resource *res = &nsio->res;
 	struct nd_pfn *nd_pfn = NULL;
 	int nid = dev_to_node(dev);
 	struct nd_pfn_sb *pfn_sb;
 	struct pmem_device *pmem;
 	struct resource pfn_res;
 	struct request_queue *q;
 	struct gendisk *disk;
 	void *addr;

 	/* while nsio_rw_bytes is active, parse a pfn info block if present */
 	if (is_nd_pfn(dev)) {
 		nd_pfn = to_nd_pfn(dev);
 		altmap = nvdimm_setup_pfn(nd_pfn, &pfn_res, &__altmap);
 		if (IS_ERR(altmap))
 			return PTR_ERR(altmap);
 	}

 	/* we're attaching a block device, disable raw namespace access */
 	devm_nsio_disable(dev, nsio);

 	pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 	if (!pmem)
 		return -ENOMEM;

 	dev_set_drvdata(dev, pmem);
 	pmem->phys_addr = res->start;
 	pmem->size = resource_size(res);
 	if (nvdimm_has_flush(nd_region) < 0)
 		dev_warn(dev, "unable to guarantee persistence of writes\n");

 	if (!devm_request_mem_region(dev, res->start, resource_size(res),
 				dev_name(&ndns->dev))) {
 		dev_warn(dev, "could not reserve region %pR\n", res);
 		return -EBUSY;
 	}

 	q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev));
 	if (!q)
 		return -ENOMEM;

 	pmem->pfn_flags = PFN_DEV;
 	if (is_nd_pfn(dev)) {
 		addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
 				altmap);
 		pfn_sb = nd_pfn->pfn_sb;
 		pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
 		pmem->pfn_pad = resource_size(res) - resource_size(&pfn_res);
 		pmem->pfn_flags |= PFN_MAP;
 		res = &pfn_res; /* for badblocks populate */
 		res->start += pmem->data_offset;
 	} else if (pmem_should_map_pages(dev)) {
 		addr = devm_memremap_pages(dev, &nsio->res,
 				&q->q_usage_counter, NULL);
 		pmem->pfn_flags |= PFN_MAP;
 	} else
 		addr = devm_memremap(dev, pmem->phys_addr,
 				pmem->size, ARCH_MEMREMAP_PMEM);

 	/*
 	 * At release time the queue must be dead before
 	 * devm_memremap_pages is unwound
 	 */
 	if (devm_add_action_or_reset(dev, pmem_release_queue, q))
 		return -ENOMEM;

 	if (IS_ERR(addr))
 		return PTR_ERR(addr);
 	pmem->virt_addr = addr;

 	blk_queue_write_cache(q, true, true);
 	blk_queue_make_request(q, pmem_make_request);
 	blk_queue_physical_block_size(q, PAGE_SIZE);
 	blk_queue_max_hw_sectors(q, UINT_MAX);
 	blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
 	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
 	queue_flag_set_unlocked(QUEUE_FLAG_DAX, q);
 	q->queuedata = pmem;

 	disk = alloc_disk_node(0, nid);
 	if (!disk)
 		return -ENOMEM;

 	disk->fops		= &pmem_fops;
 	disk->queue		= q;
 	disk->flags		= GENHD_FL_EXT_DEVT;
 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
 	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
 			/ 512);
 	if (devm_init_badblocks(dev, &pmem->bb))
 		return -ENOMEM;
 	nvdimm_badblocks_populate(nd_region, &pmem->bb, res);
 	disk->bb = &pmem->bb;
 	device_add_disk(dev, disk);

 	if (devm_add_action_or_reset(dev, pmem_release_disk, disk))
 		return -ENOMEM;

 	revalidate_disk(disk);

 	return 0;
 }

 static int nd_pmem_probe(struct device *dev)
 {
 	struct nd_namespace_common *ndns;

 	ndns = nvdimm_namespace_common_probe(dev);
 	if (IS_ERR(ndns))
 		return PTR_ERR(ndns);

 	if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev)))
 		return -ENXIO;

 	if (is_nd_btt(dev))
 		return nvdimm_namespace_attach_btt(ndns);

 	if (is_nd_pfn(dev))
 		return pmem_attach_disk(dev, ndns);

 	/* if we find a valid info-block we'll come back as that personality */
 	if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
 			|| nd_dax_probe(dev, ndns) == 0)
 		return -ENXIO;

 	/* ...otherwise we're just a raw pmem device */
 	return pmem_attach_disk(dev, ndns);
 }

 static int nd_pmem_remove(struct device *dev)
 {
 	if (is_nd_btt(dev))
 		nvdimm_namespace_detach_btt(to_nd_btt(dev));
 	nvdimm_flush(to_nd_region(dev->parent));

 	return 0;
 }

 static void nd_pmem_shutdown(struct device *dev)
 {
 	nvdimm_flush(to_nd_region(dev->parent));
 }

 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
 {
 	struct pmem_device *pmem = dev_get_drvdata(dev);
 	struct nd_region *nd_region = to_region(pmem);
 	resource_size_t offset = 0, end_trunc = 0;
 	struct nd_namespace_common *ndns;
 	struct nd_namespace_io *nsio;
 	struct resource res;

 	if (event != NVDIMM_REVALIDATE_POISON)
 		return;

 	if (is_nd_btt(dev)) {
 		struct nd_btt *nd_btt = to_nd_btt(dev);

 		ndns = nd_btt->ndns;
 	} else if (is_nd_pfn(dev)) {
 		struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 		struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;

 		ndns = nd_pfn->ndns;
 		offset = pmem->data_offset + __le32_to_cpu(pfn_sb->start_pad);
 		end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 	} else
 		ndns = to_ndns(dev);

 	nsio = to_nd_namespace_io(&ndns->dev);
 	res.start = nsio->res.start + offset;
 	res.end = nsio->res.end - end_trunc;
 	nvdimm_badblocks_populate(nd_region, &pmem->bb, &res);
 }

 MODULE_ALIAS("pmem");
 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 static struct nd_device_driver nd_pmem_driver = {
 	.probe = nd_pmem_probe,
 	.remove = nd_pmem_remove,
 	.notify = nd_pmem_notify,
 	.shutdown = nd_pmem_shutdown,
 	.drv = {
 		.name = "nd_pmem",
 	},
 	.type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 };

 static int __init pmem_init(void)
 {
 	return nd_driver_register(&nd_pmem_driver);
 }
 module_init(pmem_init);

 static void pmem_exit(void)
 {
 	driver_unregister(&nd_pmem_driver.drv);
 }
 module_exit(pmem_exit);

 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 MODULE_LICENSE("GPL v2");
	/*
	* Persistent Memory Driver
	*
	* Copyright (c) 2014-2015, Intel Corporation.
	* Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
	* Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope 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 <asm/cacheflush.h>
	#include <linux/blkdev.h>
	#include <linux/hdreg.h>
	#include <linux/init.h>
	#include <linux/platform_device.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/badblocks.h>
	#include <linux/memremap.h>
	#include <linux/vmalloc.h>
	#include <linux/pfn_t.h>
	#include <linux/slab.h>
	#include <linux/pmem.h>
	#include <linux/nd.h>
	#include "pmem.h"
	#include "pfn.h"
	#include "nd.h"

	static struct device to_dev(struct pmem_device pmem)
	{
	/*
	* nvdimm bus services need a 'dev' parameter, and we record the device
	* at init in bb.dev.
	*/
	return pmem->bb.dev;
	}

	static struct nd_region to_region(struct pmem_device pmem)
	{
	return to_nd_region(to_dev(pmem)->parent);
	}

	static int pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
	unsigned int len)
	{
	struct device *dev = to_dev(pmem);
	sector_t sector;
	long cleared;
	int rc = 0;

	sector = (offset - pmem->data_offset) / 512;

	cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
	if (cleared < len)
	rc = -EIO;
	if (cleared > 0 && cleared / 512) {
	cleared /= 512;
	dev_dbg(dev, "%s: %#llx clear %ld sector%s\n", __func__,
	(unsigned long long) sector, cleared,
	cleared > 1 ? "s" : "");
	badblocks_clear(&pmem->bb, sector, cleared);
	}

	invalidate_pmem(pmem->virt_addr + offset, len);

	return rc;
	}

	static void write_pmem(void pmem_addr, struct page page,
	unsigned int off, unsigned int len)
	{
	void *mem = kmap_atomic(page);

	memcpy_to_pmem(pmem_addr, mem + off, len);
	kunmap_atomic(mem);
	}

	static int read_pmem(struct page *page, unsigned int off,
	void *pmem_addr, unsigned int len)
	{
	int rc;
	void *mem = kmap_atomic(page);

	rc = memcpy_from_pmem(mem + off, pmem_addr, len);
	kunmap_atomic(mem);
	return rc;
	}

	static int pmem_do_bvec(struct pmem_device pmem, struct page page,
	unsigned int len, unsigned int off, bool is_write,
	sector_t sector)
	{
	int rc = 0;
	bool bad_pmem = false;
	phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
	void *pmem_addr = pmem->virt_addr + pmem_off;

	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
	bad_pmem = true;

	if (!is_write) {
	if (unlikely(bad_pmem))
	rc = -EIO;
	else {
	rc = read_pmem(page, off, pmem_addr, len);
	flush_dcache_page(page);
	}
	} else {
	/*
	* Note that we write the data both before and after
	* clearing poison. The write before clear poison
	* handles situations where the latest written data is
	* preserved and the clear poison operation simply marks
	* the address range as valid without changing the data.
	* In this case application software can assume that an
	* interrupted write will either return the new good
	* data or an error.
	*
	* However, if pmem_clear_poison() leaves the data in an
	* indeterminate state we need to perform the write
	* after clear poison.
	*/
	flush_dcache_page(page);
	write_pmem(pmem_addr, page, off, len);
	if (unlikely(bad_pmem)) {
	rc = pmem_clear_poison(pmem, pmem_off, len);
	write_pmem(pmem_addr, page, off, len);
	}
	}

	return rc;
	}

	/* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */
	#ifndef REQ_FLUSH
	#define REQ_FLUSH REQ_PREFLUSH
	#endif

	static blk_qc_t pmem_make_request(struct request_queue q, struct bio bio)
	{
	int rc = 0;
	bool do_acct;
	unsigned long start;
	struct bio_vec bvec;
	struct bvec_iter iter;
	struct pmem_device *pmem = q->queuedata;
	struct nd_region *nd_region = to_region(pmem);

	if (bio->bi_opf & REQ_FLUSH)
	nvdimm_flush(nd_region);

	do_acct = nd_iostat_start(bio, &start);
	bio_for_each_segment(bvec, bio, iter) {
	rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
	bvec.bv_offset, op_is_write(bio_op(bio)),
	iter.bi_sector);
	if (rc) {
	bio->bi_error = rc;
	break;
	}
	}
	if (do_acct)
	nd_iostat_end(bio, start);

	if (bio->bi_opf & REQ_FUA)
	nvdimm_flush(nd_region);

	bio_endio(bio);
	return BLK_QC_T_NONE;
	}

	static int pmem_rw_page(struct block_device *bdev, sector_t sector,
	struct page *page, bool is_write)
	{
	struct pmem_device *pmem = bdev->bd_queue->queuedata;
	int rc;

	rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, is_write, sector);

	/*
	* The ->rw_page interface is subtle and tricky. The core
	* retries on any error, so we can only invoke page_endio() in
	* the successful completion case. Otherwise, we'll see crashes
	* caused by double completion.
	*/
	if (rc == 0)
	page_endio(page, is_write, 0);

	return rc;
	}

	/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
	__weak long pmem_direct_access(struct block_device *bdev, sector_t sector,
	void *kaddr, pfn_t pfn, long size)
	{
	struct pmem_device *pmem = bdev->bd_queue->queuedata;
	resource_size_t offset = sector * 512 + pmem->data_offset;

	if (unlikely(is_bad_pmem(&pmem->bb, sector, size)))
	return -EIO;
	*kaddr = pmem->virt_addr + offset;
	*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);

	/*
	* If badblocks are present, limit known good range to the
	* requested range.
	*/
	if (unlikely(pmem->bb.count))
	return size;
	return pmem->size - pmem->pfn_pad - offset;
	}

	static const struct block_device_operations pmem_fops = {
	.owner = THIS_MODULE,
	.rw_page = pmem_rw_page,
	.direct_access = pmem_direct_access,
	.revalidate_disk = nvdimm_revalidate_disk,
	};

	static void pmem_release_queue(void *q)
	{
	blk_cleanup_queue(q);
	}

	static void pmem_release_disk(void *disk)
	{
	del_gendisk(disk);
	put_disk(disk);
	}

	static int pmem_attach_disk(struct device *dev,
	struct nd_namespace_common *ndns)
	{
	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
	struct nd_region *nd_region = to_nd_region(dev->parent);
	struct vmem_altmap __altmap, *altmap = NULL;
	struct resource *res = &nsio->res;
	struct nd_pfn *nd_pfn = NULL;
	int nid = dev_to_node(dev);
	struct nd_pfn_sb *pfn_sb;
	struct pmem_device *pmem;
	struct resource pfn_res;
	struct request_queue *q;
	struct gendisk *disk;
	void *addr;

	/* while nsio_rw_bytes is active, parse a pfn info block if present */
	if (is_nd_pfn(dev)) {
	nd_pfn = to_nd_pfn(dev);
	altmap = nvdimm_setup_pfn(nd_pfn, &pfn_res, &__altmap);
	if (IS_ERR(altmap))
	return PTR_ERR(altmap);
	}

	/* we're attaching a block device, disable raw namespace access */
	devm_nsio_disable(dev, nsio);

	pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
	if (!pmem)
	return -ENOMEM;

	dev_set_drvdata(dev, pmem);
	pmem->phys_addr = res->start;
	pmem->size = resource_size(res);
	if (nvdimm_has_flush(nd_region) < 0)
	dev_warn(dev, "unable to guarantee persistence of writes\n");

	if (!devm_request_mem_region(dev, res->start, resource_size(res),
	dev_name(&ndns->dev))) {
	dev_warn(dev, "could not reserve region %pR\n", res);
	return -EBUSY;
	}

	q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev));
	if (!q)
	return -ENOMEM;

	pmem->pfn_flags = PFN_DEV;
	if (is_nd_pfn(dev)) {
	addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
	altmap);
	pfn_sb = nd_pfn->pfn_sb;
	pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
	pmem->pfn_pad = resource_size(res) - resource_size(&pfn_res);
	pmem->pfn_flags \|= PFN_MAP;
	res = &pfn_res; /* for badblocks populate */
	res->start += pmem->data_offset;
	} else if (pmem_should_map_pages(dev)) {
	addr = devm_memremap_pages(dev, &nsio->res,
	&q->q_usage_counter, NULL);
	pmem->pfn_flags \|= PFN_MAP;
	} else
	addr = devm_memremap(dev, pmem->phys_addr,
	pmem->size, ARCH_MEMREMAP_PMEM);

	/*
	* At release time the queue must be dead before
	* devm_memremap_pages is unwound
	*/
	if (devm_add_action_or_reset(dev, pmem_release_queue, q))
	return -ENOMEM;

	if (IS_ERR(addr))
	return PTR_ERR(addr);
	pmem->virt_addr = addr;

	blk_queue_write_cache(q, true, true);
	blk_queue_make_request(q, pmem_make_request);
	blk_queue_physical_block_size(q, PAGE_SIZE);
	blk_queue_max_hw_sectors(q, UINT_MAX);
	blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
	queue_flag_set_unlocked(QUEUE_FLAG_DAX, q);
	q->queuedata = pmem;

	disk = alloc_disk_node(0, nid);
	if (!disk)
	return -ENOMEM;

	disk->fops = &pmem_fops;
	disk->queue = q;
	disk->flags = GENHD_FL_EXT_DEVT;
	nvdimm_namespace_disk_name(ndns, disk->disk_name);
	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
	/ 512);
	if (devm_init_badblocks(dev, &pmem->bb))
	return -ENOMEM;
	nvdimm_badblocks_populate(nd_region, &pmem->bb, res);
	disk->bb = &pmem->bb;
	device_add_disk(dev, disk);

	if (devm_add_action_or_reset(dev, pmem_release_disk, disk))
	return -ENOMEM;

	revalidate_disk(disk);

	return 0;
	}

	static int nd_pmem_probe(struct device *dev)
	{
	struct nd_namespace_common *ndns;

	ndns = nvdimm_namespace_common_probe(dev);
	if (IS_ERR(ndns))
	return PTR_ERR(ndns);

	if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev)))
	return -ENXIO;

	if (is_nd_btt(dev))
	return nvdimm_namespace_attach_btt(ndns);

	if (is_nd_pfn(dev))
	return pmem_attach_disk(dev, ndns);

	/* if we find a valid info-block we'll come back as that personality */
	if (nd_btt_probe(dev, ndns) == 0 \|\| nd_pfn_probe(dev, ndns) == 0
	\|\| nd_dax_probe(dev, ndns) == 0)
	return -ENXIO;

	/* ...otherwise we're just a raw pmem device */
	return pmem_attach_disk(dev, ndns);
	}

	static int nd_pmem_remove(struct device *dev)
	{
	if (is_nd_btt(dev))
	nvdimm_namespace_detach_btt(to_nd_btt(dev));
	nvdimm_flush(to_nd_region(dev->parent));

	return 0;
	}

	static void nd_pmem_shutdown(struct device *dev)
	{
	nvdimm_flush(to_nd_region(dev->parent));
	}

	static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
	{
	struct pmem_device *pmem = dev_get_drvdata(dev);
	struct nd_region *nd_region = to_region(pmem);
	resource_size_t offset = 0, end_trunc = 0;
	struct nd_namespace_common *ndns;
	struct nd_namespace_io *nsio;
	struct resource res;

	if (event != NVDIMM_REVALIDATE_POISON)
	return;

	if (is_nd_btt(dev)) {
	struct nd_btt *nd_btt = to_nd_btt(dev);

	ndns = nd_btt->ndns;
	} else if (is_nd_pfn(dev)) {
	struct nd_pfn *nd_pfn = to_nd_pfn(dev);
	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;

	ndns = nd_pfn->ndns;
	offset = pmem->data_offset + __le32_to_cpu(pfn_sb->start_pad);
	end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
	} else
	ndns = to_ndns(dev);

	nsio = to_nd_namespace_io(&ndns->dev);
	res.start = nsio->res.start + offset;
	res.end = nsio->res.end - end_trunc;
	nvdimm_badblocks_populate(nd_region, &pmem->bb, &res);
	}

	MODULE_ALIAS("pmem");
	MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
	MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
	static struct nd_device_driver nd_pmem_driver = {
	.probe = nd_pmem_probe,
	.remove = nd_pmem_remove,
	.notify = nd_pmem_notify,
	.shutdown = nd_pmem_shutdown,
	.drv = {
	.name = "nd_pmem",
	},
	.type = ND_DRIVER_NAMESPACE_IO \| ND_DRIVER_NAMESPACE_PMEM,
	};

	static int __init pmem_init(void)
	{
	return nd_driver_register(&nd_pmem_driver);
	}
	module_init(pmem_init);

	static void pmem_exit(void)
	{
	driver_unregister(&nd_pmem_driver.drv);
	}
	module_exit(pmem_exit);

	MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
	MODULE_LICENSE("GPL v2");