Merge tag 'libnvdimm-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Ross Zwisler:

 - Require struct page by default for filesystem DAX to remove a number
   of surprising failure cases. This includes failures with direct I/O,
   gdb and fork(2).

 - Add support for the new Platform Capabilities Structure added to the
   NFIT in ACPI 6.2a. This new table tells us whether the platform
   supports flushing of CPU and memory controller caches on unexpected
   power loss events.

 - Revamp vmem_altmap and dev_pagemap handling to clean up code and
   better support future future PCI P2P uses.

 - Deprecate the ND_IOCTL_SMART_THRESHOLD command whose payload has
   become out-of-sync with recent versions of the NVDIMM_FAMILY_INTEL
   spec, and instead rely on the generic ND_CMD_CALL approach used by
   the two other IOCTL families, NVDIMM_FAMILY_{HPE,MSFT}.

 - Enhance nfit_test so we can test some of the new things added in
   version 1.6 of the DSM specification. This includes testing firmware
   download and simulating the Last Shutdown State (LSS) status.

* tag 'libnvdimm-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (37 commits)
  libnvdimm, namespace: remove redundant initialization of 'nd_mapping'
  acpi, nfit: fix register dimm error handling
  libnvdimm, namespace: make min namespace size 4K
  tools/testing/nvdimm: force nfit_test to depend on instrumented modules
  libnvdimm/nfit_test: adding support for unit testing enable LSS status
  libnvdimm/nfit_test: add firmware download emulation
  nfit-test: Add platform cap support from ACPI 6.2a to test
  libnvdimm: expose platform persistence attribute for nd_region
  acpi: nfit: add persistent memory control flag for nd_region
  acpi: nfit: Add support for detect platform CPU cache flush on power loss
  device-dax: Fix trailing semicolon
  libnvdimm, btt: fix uninitialized err_lock
  dax: require 'struct page' by default for filesystem dax
  ext2: auto disable dax instead of failing mount
  ext4: auto disable dax instead of failing mount
  mm, dax: introduce pfn_t_special()
  mm: Fix devm_memremap_pages() collision handling
  mm: Fix memory size alignment in devm_memremap_pages_release()
  memremap: merge find_dev_pagemap into get_dev_pagemap
  memremap: change devm_memremap_pages interface to use struct dev_pagemap
  ...

15 files changed, 110 insertions, 51 deletions

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index abeb4df4f22e..bbe48ad20886 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -838,6 +838,18 @@ static bool add_flush(struct acpi_nfit_desc *acpi_desc,
 	return true;
 }
 
+static bool add_platform_cap(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_capabilities *pcap)
+{
+	struct device *dev = acpi_desc->dev;
+	u32 mask;
+
+	mask = (1 << (pcap->highest_capability + 1)) - 1;
+	acpi_desc->platform_cap = pcap->capabilities & mask;
+	dev_dbg(dev, "%s: cap: %#x\n", __func__, acpi_desc->platform_cap);
+	return true;
+}
+
 static void *add_table(struct acpi_nfit_desc *acpi_desc,
 		struct nfit_table_prev *prev, void *table, const void *end)
 {
@@ -883,6 +895,10 @@ static void *add_table(struct acpi_nfit_desc *acpi_desc,
 	case ACPI_NFIT_TYPE_SMBIOS:
 		dev_dbg(dev, "%s: smbios\n", __func__);
 		break;
+	case ACPI_NFIT_TYPE_CAPABILITIES:
+		if (!add_platform_cap(acpi_desc, table))
+			return err;
+		break;
 	default:
 		dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
 		break;
@@ -1867,6 +1883,9 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 		struct kernfs_node *nfit_kernfs;
 
 		nvdimm = nfit_mem->nvdimm;
+		if (!nvdimm)
+			continue;
+
 		nfit_kernfs = sysfs_get_dirent(nvdimm_kobj(nvdimm)->sd, "nfit");
 		if (nfit_kernfs)
 			nfit_mem->flags_attr = sysfs_get_dirent(nfit_kernfs,
@@ -2656,6 +2675,12 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 	else
 		ndr_desc->numa_node = NUMA_NO_NODE;
 
+	if(acpi_desc->platform_cap & ACPI_NFIT_CAPABILITY_CACHE_FLUSH)
+		set_bit(ND_REGION_PERSIST_CACHE, &ndr_desc->flags);
+
+	if (acpi_desc->platform_cap & ACPI_NFIT_CAPABILITY_MEM_FLUSH)
+		set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc->flags);
+
 	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
 		struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
 		struct nd_mapping_desc *mapping;
@@ -3464,6 +3489,7 @@ static __init int nfit_init(void)
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 9);
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_control_region) != 80);
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_data_region) != 40);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_capabilities) != 16);
 
 	guid_parse(UUID_VOLATILE_MEMORY, &nfit_uuid[NFIT_SPA_VOLATILE]);
 	guid_parse(UUID_PERSISTENT_MEMORY, &nfit_uuid[NFIT_SPA_PM]);
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index f0cf18b2da8b..50d36e166d70 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -202,6 +202,7 @@ struct acpi_nfit_desc {
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
 	unsigned long bus_nfit_cmd_force_en;
+	unsigned int platform_cap;
 	int (*blk_do_io)(struct nd_blk_region *ndbr, resource_size_t dpa,
 			void *iobuf, u64 len, int rw);
 };
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 7b0bf825c4e7..2137dbc29877 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -133,7 +133,7 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 	dax_region->base = addr;
 	if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
 		kfree(dax_region);
-		return NULL;;
+		return NULL;
 	}
 
 	kref_get(&dax_region->kref);
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 8d8c852ba8f2..31b6ecce4c64 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -21,6 +21,7 @@
 struct dax_pmem {
 	struct device *dev;
 	struct percpu_ref ref;
+	struct dev_pagemap pgmap;
 	struct completion cmp;
 };
 
@@ -69,20 +70,23 @@ static int dax_pmem_probe(struct device *dev)
 	struct nd_namespace_common *ndns;
 	struct nd_dax *nd_dax = to_nd_dax(dev);
 	struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
-	struct vmem_altmap __altmap, *altmap = NULL;
 
 	ndns = nvdimm_namespace_common_probe(dev);
 	if (IS_ERR(ndns))
 		return PTR_ERR(ndns);
 	nsio = to_nd_namespace_io(&ndns->dev);
 
+	dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
+	if (!dax_pmem)
+		return -ENOMEM;
+
 	/* parse the 'pfn' info block via ->rw_bytes */
 	rc = devm_nsio_enable(dev, nsio);
 	if (rc)
 		return rc;
-	altmap = nvdimm_setup_pfn(nd_pfn, &res, &__altmap);
-	if (IS_ERR(altmap))
-		return PTR_ERR(altmap);
+	rc = nvdimm_setup_pfn(nd_pfn, &dax_pmem->pgmap);
+	if (rc)
+		return rc;
 	devm_nsio_disable(dev, nsio);
 
 	pfn_sb = nd_pfn->pfn_sb;
@@ -94,10 +98,6 @@ static int dax_pmem_probe(struct device *dev)
 		return -EBUSY;
 	}
 
-	dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
-	if (!dax_pmem)
-		return -ENOMEM;
-
 	dax_pmem->dev = dev;
 	init_completion(&dax_pmem->cmp);
 	rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0,
@@ -110,7 +110,8 @@ static int dax_pmem_probe(struct device *dev)
 	if (rc)
 		return rc;
 
-	addr = devm_memremap_pages(dev, &res, &dax_pmem->ref, altmap);
+	dax_pmem->pgmap.ref = &dax_pmem->ref;
+	addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
 	if (IS_ERR(addr))
 		return PTR_ERR(addr);
 
@@ -120,6 +121,7 @@ static int dax_pmem_probe(struct device *dev)
 		return rc;
 
 	/* adjust the dax_region resource to the start of data */
+	memcpy(&res, &dax_pmem->pgmap.res, sizeof(res));
 	res.start += le64_to_cpu(pfn_sb->dataoff);
 
 	rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 3ec804672601..473af694ad1c 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -15,6 +15,7 @@
 #include <linux/mount.h>
 #include <linux/magic.h>
 #include <linux/genhd.h>
+#include <linux/pfn_t.h>
 #include <linux/cdev.h>
 #include <linux/hash.h>
 #include <linux/slab.h>
@@ -123,6 +124,15 @@ int __bdev_dax_supported(struct super_block *sb, int blocksize)
 		return len < 0 ? len : -EIO;
 	}
 
+	if ((IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn))
+			|| pfn_t_devmap(pfn))
+		/* pass */;
+	else {
+		pr_debug("VFS (%s): error: dax support not enabled\n",
+				sb->s_id);
+		return -EOPNOTSUPP;
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(__bdev_dax_supported);
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index c586bcdb5190..2ef544f10ec8 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -753,6 +753,7 @@ static struct arena_info *alloc_arena(struct btt *btt, size_t size,
 		return NULL;
 	arena->nd_btt = btt->nd_btt;
 	arena->sector_size = btt->sector_size;
+	mutex_init(&arena->err_lock);
 
 	if (!size)
 		return arena;
@@ -891,7 +892,6 @@ static int discover_arenas(struct btt *btt)
 			goto out;
 		}
 
-		mutex_init(&arena->err_lock);
 		ret = btt_freelist_init(arena);
 		if (ret)
 			goto out;
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 0a5e6cd758fe..78eabc3a1ab1 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -1142,9 +1142,6 @@ int __init nvdimm_bus_init(void)
 {
 	int rc;
 
-	BUILD_BUG_ON(sizeof(struct nd_smart_payload) != 128);
-	BUILD_BUG_ON(sizeof(struct nd_smart_threshold_payload) != 8);
-
 	rc = bus_register(&nvdimm_bus_type);
 	if (rc)
 		return rc;
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index bb3ba8cf24d4..658ada497be0 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -2408,7 +2408,7 @@ static struct device **scan_labels(struct nd_region *nd_region)
 
 static struct device **create_namespaces(struct nd_region *nd_region)
 {
-	struct nd_mapping *nd_mapping = &nd_region->mapping[0];
+	struct nd_mapping *nd_mapping;
 	struct device **devs;
 	int i;
 
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index e958f3724c41..8d6375ee0fda 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -368,15 +368,14 @@ unsigned int pmem_sector_size(struct nd_namespace_common *ndns);
 void nvdimm_badblocks_populate(struct nd_region *nd_region,
 		struct badblocks *bb, const struct resource *res);
 #if IS_ENABLED(CONFIG_ND_CLAIM)
-struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
-		struct resource *res, struct vmem_altmap *altmap);
+int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap);
 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio);
 void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio);
 #else
-static inline struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
-		struct resource *res, struct vmem_altmap *altmap)
+static inline int nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
+				   struct dev_pagemap *pgmap)
 {
-	return ERR_PTR(-ENXIO);
+	return -ENXIO;
 }
 static inline int devm_nsio_enable(struct device *dev,
 		struct nd_namespace_io *nsio)
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 2adada1a5855..f5c4e8c6e29d 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -542,9 +542,10 @@ static unsigned long init_altmap_reserve(resource_size_t base)
 	return reserve;
 }
 
-static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
-		struct resource *res, struct vmem_altmap *altmap)
+static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 {
+	struct resource *res = &pgmap->res;
+	struct vmem_altmap *altmap = &pgmap->altmap;
 	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 	u64 offset = le64_to_cpu(pfn_sb->dataoff);
 	u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
@@ -561,11 +562,13 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 	res->start += start_pad;
 	res->end -= end_trunc;
 
+	pgmap->type = MEMORY_DEVICE_HOST;
+
 	if (nd_pfn->mode == PFN_MODE_RAM) {
 		if (offset < SZ_8K)
-			return ERR_PTR(-EINVAL);
+			return -EINVAL;
 		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
-		altmap = NULL;
+		pgmap->altmap_valid = false;
 	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
 		nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
 					- offset) / PAGE_SIZE);
@@ -577,10 +580,11 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 		memcpy(altmap, &__altmap, sizeof(*altmap));
 		altmap->free = PHYS_PFN(offset - SZ_8K);
 		altmap->alloc = 0;
+		pgmap->altmap_valid = true;
 	} else
-		return ERR_PTR(-ENXIO);
+		return -ENXIO;
 
-	return altmap;
+	return 0;
 }
 
 static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys)
@@ -708,19 +712,18 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
  * Determine the effective resource range and vmem_altmap from an nd_pfn
  * instance.
  */
-struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
-		struct resource *res, struct vmem_altmap *altmap)
+int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 {
 	int rc;
 
 	if (!nd_pfn->uuid || !nd_pfn->ndns)
-		return ERR_PTR(-ENODEV);
+		return -ENODEV;
 
 	rc = nd_pfn_init(nd_pfn);
 	if (rc)
-		return ERR_PTR(rc);
+		return rc;
 
-	/* we need a valid pfn_sb before we can init a vmem_altmap */
-	return __nvdimm_setup_pfn(nd_pfn, res, altmap);
+	/* we need a valid pfn_sb before we can init a dev_pagemap */
+	return __nvdimm_setup_pfn(nd_pfn, pgmap);
 }
 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 7fbc5c5dc8e1..10041ac4032c 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -35,6 +35,7 @@
 #include "pmem.h"
 #include "pfn.h"
 #include "nd.h"
+#include "nd-core.h"
 
 static struct device *to_dev(struct pmem_device *pmem)
 {
@@ -298,34 +299,34 @@ static int pmem_attach_disk(struct device *dev,
 {
 	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;
 	int nid = dev_to_node(dev), fua, wbc;
 	struct resource *res = &nsio->res;
+	struct resource bb_res;
 	struct nd_pfn *nd_pfn = NULL;
 	struct dax_device *dax_dev;
 	struct nd_pfn_sb *pfn_sb;
 	struct pmem_device *pmem;
-	struct resource pfn_res;
 	struct request_queue *q;
 	struct device *gendev;
 	struct gendisk *disk;
 	void *addr;
+	int rc;
+
+	pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
+	if (!pmem)
+		return -ENOMEM;
 
 	/* 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);
+		rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
+		if (rc)
+			return rc;
 	}
 
 	/* 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);
@@ -334,7 +335,8 @@ static int pmem_attach_disk(struct device *dev,
 		dev_warn(dev, "unable to guarantee persistence of writes\n");
 		fua = 0;
 	}
-	wbc = nvdimm_has_cache(nd_region);
+	wbc = nvdimm_has_cache(nd_region) &&
+		!test_bit(ND_REGION_PERSIST_CACHE, &nd_region->flags);
 
 	if (!devm_request_mem_region(dev, res->start, resource_size(res),
 				dev_name(&ndns->dev))) {
@@ -350,19 +352,22 @@ static int pmem_attach_disk(struct device *dev,
 		return -ENOMEM;
 
 	pmem->pfn_flags = PFN_DEV;
+	pmem->pgmap.ref = &q->q_usage_counter;
 	if (is_nd_pfn(dev)) {
-		addr = devm_memremap_pages(dev, &pfn_res, &q->q_usage_counter,
-				altmap);
+		addr = devm_memremap_pages(dev, &pmem->pgmap);
 		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_pad = resource_size(res) -
+			resource_size(&pmem->pgmap.res);
 		pmem->pfn_flags |= PFN_MAP;
-		res = &pfn_res; /* for badblocks populate */
-		res->start += pmem->data_offset;
+		memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
+		bb_res.start += pmem->data_offset;
 	} else if (pmem_should_map_pages(dev)) {
-		addr = devm_memremap_pages(dev, &nsio->res,
-				&q->q_usage_counter, NULL);
+		memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
+		pmem->pgmap.altmap_valid = false;
+		addr = devm_memremap_pages(dev, &pmem->pgmap);
 		pmem->pfn_flags |= PFN_MAP;
+		memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
 	} else
 		addr = devm_memremap(dev, pmem->phys_addr,
 				pmem->size, ARCH_MEMREMAP_PMEM);
@@ -401,7 +406,7 @@ static int pmem_attach_disk(struct device *dev,
 			/ 512);
 	if (devm_init_badblocks(dev, &pmem->bb))
 		return -ENOMEM;
-	nvdimm_badblocks_populate(nd_region, &pmem->bb, res);
+	nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_res);
 	disk->bb = &pmem->bb;
 
 	dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops);
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
index 6a3cd2a10db6..a64ebc78b5df 100644
--- a/drivers/nvdimm/pmem.h
+++ b/drivers/nvdimm/pmem.h
@@ -22,6 +22,7 @@ struct pmem_device {
 	struct badblocks	bb;
 	struct dax_device	*dax_dev;
 	struct gendisk		*disk;
+	struct dev_pagemap	pgmap;
 };
 
 long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index abaf38c61220..e6d01911e092 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -528,6 +528,18 @@ static ssize_t resource_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(resource);
 
+static ssize_t persistence_domain_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nd_region *nd_region = to_nd_region(dev);
+	unsigned long flags = nd_region->flags;
+
+	return sprintf(buf, "%s%s\n",
+			flags & BIT(ND_REGION_PERSIST_CACHE) ? "cpu_cache " : "",
+			flags & BIT(ND_REGION_PERSIST_MEMCTRL) ? "memory_controller " : "");
+}
+static DEVICE_ATTR_RO(persistence_domain);
+
 static struct attribute *nd_region_attributes[] = {
 	&dev_attr_size.attr,
 	&dev_attr_nstype.attr,
@@ -543,6 +555,7 @@ static struct attribute *nd_region_attributes[] = {
 	&dev_attr_init_namespaces.attr,
 	&dev_attr_badblocks.attr,
 	&dev_attr_resource.attr,
+	&dev_attr_persistence_domain.attr,
 	NULL,
 };
 
diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
index bc27d716aa6b..1444333210c7 100644
--- a/drivers/s390/block/Kconfig
+++ b/drivers/s390/block/Kconfig
@@ -16,6 +16,7 @@ config BLK_DEV_XPRAM
 config DCSSBLK
 	def_tristate m
 	select DAX
+	select FS_DAX_LIMITED
 	prompt "DCSSBLK support"
 	depends on S390 && BLOCK
 	help
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 6aaefb780436..9cae08b36b80 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -916,7 +916,8 @@ __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff,
 
 	dev_sz = dev_info->end - dev_info->start + 1;
 	*kaddr = (void *) dev_info->start + offset;
-	*pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), PFN_DEV);
+	*pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset),
+			PFN_DEV|PFN_SPECIAL);
 
 	return (dev_sz - offset) / PAGE_SIZE;
 }