if (ndns->force_raw)
                return -ENODEV;
 
+       switch (ndns->claim_class) {
+       case NVDIMM_CCLASS_NONE:
+       case NVDIMM_CCLASS_BTT:
+               break;
+       default:
+               return -ENODEV;
+       }
+
        nvdimm_bus_lock(&ndns->dev);
        btt_dev = __nd_btt_create(nd_region, 0, NULL, ndns);
        nvdimm_bus_unlock(&ndns->dev);
 
        }
 
        ndns = to_ndns(found);
+
+       switch (ndns->claim_class) {
+       case NVDIMM_CCLASS_NONE:
+               break;
+       case NVDIMM_CCLASS_BTT:
+               if (!is_nd_btt(dev)) {
+                       len = -EBUSY;
+                       goto out_attach;
+               }
+               break;
+       case NVDIMM_CCLASS_PFN:
+               if (!is_nd_pfn(dev)) {
+                       len = -EBUSY;
+                       goto out_attach;
+               }
+               break;
+       case NVDIMM_CCLASS_DAX:
+               if (!is_nd_dax(dev)) {
+                       len = -EBUSY;
+                       goto out_attach;
+               }
+               break;
+       default:
+               len = -EBUSY;
+               goto out_attach;
+               break;
+       }
+
        if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
                dev_dbg(dev, "%s too small to host\n", name);
                len = -ENXIO;
 
        rc = nd_region_init();
        if (rc)
                goto err_region;
+
+       nd_label_init();
+
        return 0;
  err_region:
        nvdimm_exit();
 
        if (ndns->force_raw)
                return -ENODEV;
 
+       switch (ndns->claim_class) {
+       case NVDIMM_CCLASS_NONE:
+       case NVDIMM_CCLASS_DAX:
+               break;
+       default:
+               return -ENODEV;
+       }
+
        nvdimm_bus_lock(&ndns->dev);
        nd_dax = nd_dax_alloc(nd_region);
        nd_pfn = &nd_dax->nd_pfn;
 
  */
 #include <linux/device.h>
 #include <linux/ndctl.h>
+#include <linux/uuid.h>
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/nd.h>
 #include "label.h"
 #include "nd.h"
 
+static guid_t nvdimm_btt_guid;
+static guid_t nvdimm_pfn_guid;
+static guid_t nvdimm_dax_guid;
+
 static u32 best_seq(u32 a, u32 b)
 {
        a &= NSINDEX_SEQ_MASK;
                - (unsigned long) to_namespace_index(ndd, 0);
 }
 
+enum nvdimm_claim_class to_nvdimm_cclass(guid_t *guid)
+{
+       if (guid_equal(guid, &nvdimm_btt_guid))
+               return NVDIMM_CCLASS_BTT;
+       else if (guid_equal(guid, &nvdimm_pfn_guid))
+               return NVDIMM_CCLASS_PFN;
+       else if (guid_equal(guid, &nvdimm_dax_guid))
+               return NVDIMM_CCLASS_DAX;
+       else if (guid_equal(guid, &guid_null))
+               return NVDIMM_CCLASS_NONE;
+
+       return NVDIMM_CCLASS_UNKNOWN;
+}
+
+static const guid_t *to_abstraction_guid(enum nvdimm_claim_class claim_class,
+       guid_t *target)
+{
+       if (claim_class == NVDIMM_CCLASS_BTT)
+               return &nvdimm_btt_guid;
+       else if (claim_class == NVDIMM_CCLASS_PFN)
+               return &nvdimm_pfn_guid;
+       else if (claim_class == NVDIMM_CCLASS_DAX)
+               return &nvdimm_dax_guid;
+       else if (claim_class == NVDIMM_CCLASS_UNKNOWN) {
+               /*
+                * If we're modifying a namespace for which we don't
+                * know the claim_class, don't touch the existing guid.
+                */
+               return target;
+       } else
+               return &guid_null;
+}
+
 static int __pmem_label_update(struct nd_region *nd_region,
                struct nd_mapping *nd_mapping, struct nd_namespace_pmem *nspm,
                int pos)
 {
+       struct nd_namespace_common *ndns = &nspm->nsio.common;
        struct nd_interleave_set *nd_set = nd_region->nd_set;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct nd_label_ent *label_ent, *victim = NULL;
        nd_label->slot = __cpu_to_le32(slot);
        if (namespace_label_has(ndd, type_guid))
                guid_copy(&nd_label->type_guid, &nd_set->type_guid);
+       if (namespace_label_has(ndd, abstraction_guid))
+               guid_copy(&nd_label->abstraction_guid,
+                               to_abstraction_guid(ndns->claim_class,
+                                       &nd_label->abstraction_guid));
        if (namespace_label_has(ndd, checksum)) {
                u64 sum;
 
 {
        int i, alloc, victims, nfree, old_num_resources, nlabel, rc = -ENXIO;
        struct nd_interleave_set *nd_set = nd_region->nd_set;
+       struct nd_namespace_common *ndns = &nsblk->common;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct nd_namespace_label *nd_label;
        struct nd_label_ent *label_ent, *e;
                nd_label->slot = __cpu_to_le32(slot);
                if (namespace_label_has(ndd, type_guid))
                        guid_copy(&nd_label->type_guid, &nd_set->type_guid);
+               if (namespace_label_has(ndd, abstraction_guid))
+                       guid_copy(&nd_label->abstraction_guid,
+                                       to_abstraction_guid(ndns->claim_class,
+                                               &nd_label->abstraction_guid));
+
                if (namespace_label_has(ndd, checksum)) {
                        u64 sum;
 
 
        return __blk_label_update(nd_region, nd_mapping, nsblk, count);
 }
+
+int __init nd_label_init(void)
+{
+       WARN_ON(guid_parse(NVDIMM_BTT_GUID, &nvdimm_btt_guid));
+       WARN_ON(guid_parse(NVDIMM_PFN_GUID, &nvdimm_pfn_guid));
+       WARN_ON(guid_parse(NVDIMM_DAX_GUID, &nvdimm_dax_guid));
+
+       return 0;
+}
 
        __le64 checksum;
 };
 
+#define NVDIMM_BTT_GUID "8aed63a2-29a2-4c66-8b12-f05d15d3922a"
+#define NVDIMM_PFN_GUID "266400ba-fb9f-4677-bcb0-968f11d0d225"
+#define NVDIMM_DAX_GUID "97a86d9c-3cdd-4eda-986f-5068b4f80088"
+
 /**
  * struct nd_label_id - identifier string for dpa allocation
  * @id: "{blk|pmem}-<namespace uuid>"
 u32 nd_label_alloc_slot(struct nvdimm_drvdata *ndd);
 bool nd_label_free_slot(struct nvdimm_drvdata *ndd, u32 slot);
 u32 nd_label_nfree(struct nvdimm_drvdata *ndd);
+enum nvdimm_claim_class to_nvdimm_cclass(guid_t *guid);
 struct nd_region;
 struct nd_namespace_pmem;
 struct nd_namespace_blk;
 
 }
 static DEVICE_ATTR_RO(holder);
 
+static ssize_t __holder_class_store(struct device *dev, const char *buf)
+{
+       struct nd_namespace_common *ndns = to_ndns(dev);
+
+       if (dev->driver || ndns->claim)
+               return -EBUSY;
+
+       if (strcmp(buf, "btt") == 0 || strcmp(buf, "btt\n") == 0)
+               ndns->claim_class = NVDIMM_CCLASS_BTT;
+       else if (strcmp(buf, "pfn") == 0 || strcmp(buf, "pfn\n") == 0)
+               ndns->claim_class = NVDIMM_CCLASS_PFN;
+       else if (strcmp(buf, "dax") == 0 || strcmp(buf, "dax\n") == 0)
+               ndns->claim_class = NVDIMM_CCLASS_DAX;
+       else if (strcmp(buf, "") == 0 || strcmp(buf, "\n") == 0)
+               ndns->claim_class = NVDIMM_CCLASS_NONE;
+       else
+               return -EINVAL;
+
+       return 0;
+}
+
+static ssize_t holder_class_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t len)
+{
+       struct nd_region *nd_region = to_nd_region(dev->parent);
+       ssize_t rc;
+
+       device_lock(dev);
+       nvdimm_bus_lock(dev);
+       wait_nvdimm_bus_probe_idle(dev);
+       rc = __holder_class_store(dev, buf);
+       if (rc >= 0)
+               rc = nd_namespace_label_update(nd_region, dev);
+       dev_dbg(dev, "%s: %s(%zd)\n", __func__, rc < 0 ? "fail " : "", rc);
+       nvdimm_bus_unlock(dev);
+       device_unlock(dev);
+
+       return rc < 0 ? rc : len;
+}
+
+static ssize_t holder_class_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct nd_namespace_common *ndns = to_ndns(dev);
+       ssize_t rc;
+
+       device_lock(dev);
+       if (ndns->claim_class == NVDIMM_CCLASS_NONE)
+               rc = sprintf(buf, "\n");
+       else if (ndns->claim_class == NVDIMM_CCLASS_BTT)
+               rc = sprintf(buf, "btt\n");
+       else if (ndns->claim_class == NVDIMM_CCLASS_PFN)
+               rc = sprintf(buf, "pfn\n");
+       else if (ndns->claim_class == NVDIMM_CCLASS_DAX)
+               rc = sprintf(buf, "dax\n");
+       else
+               rc = sprintf(buf, "<unknown>\n");
+       device_unlock(dev);
+
+       return rc;
+}
+static DEVICE_ATTR_RW(holder_class);
+
 static ssize_t mode_show(struct device *dev,
                struct device_attribute *attr, char *buf)
 {
        &dev_attr_force_raw.attr,
        &dev_attr_sector_size.attr,
        &dev_attr_dpa_extents.attr,
+       &dev_attr_holder_class.attr,
        NULL,
 };
 
 
        if (a == &dev_attr_nstype.attr || a == &dev_attr_size.attr
                        || a == &dev_attr_holder.attr
+                       || a == &dev_attr_holder_class.attr
                        || a == &dev_attr_force_raw.attr
                        || a == &dev_attr_mode.attr)
                return a->mode;
        /* Calculate total size and populate namespace properties from label0 */
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_namespace_label *label0;
+               struct nvdimm_drvdata *ndd;
 
                nd_mapping = &nd_region->mapping[i];
                label_ent = list_first_entry_or_null(&nd_mapping->labels,
                nspm->uuid = kmemdup((void __force *) label0->uuid,
                                NSLABEL_UUID_LEN, GFP_KERNEL);
                nspm->lbasize = __le64_to_cpu(label0->lbasize);
+               ndd = to_ndd(nd_mapping);
+               if (namespace_label_has(ndd, abstraction_guid))
+                       nspm->nsio.common.claim_class
+                               = to_nvdimm_cclass(&label0->abstraction_guid);
+
        }
 
        if (!nspm->alt_name || !nspm->uuid) {
        nsblk->lbasize = __le64_to_cpu(nd_label->lbasize);
        nsblk->uuid = kmemdup(nd_label->uuid, NSLABEL_UUID_LEN,
                        GFP_KERNEL);
+       if (namespace_label_has(ndd, abstraction_guid))
+               nsblk->common.claim_class
+                       = to_nvdimm_cclass(&nd_label->abstraction_guid);
        if (!nsblk->uuid)
                goto blk_err;
        memcpy(name, nd_label->name, NSLABEL_NAME_LEN);
 
                unsigned long *current_lbasize, const unsigned long *supported);
 int __init nvdimm_init(void);
 int __init nd_region_init(void);
+int __init nd_label_init(void);
 void nvdimm_exit(void);
 void nd_region_exit(void);
 struct nvdimm;
 
        if (ndns->force_raw)
                return -ENODEV;
 
+       switch (ndns->claim_class) {
+       case NVDIMM_CCLASS_NONE:
+       case NVDIMM_CCLASS_PFN:
+               break;
+       default:
+               return -ENODEV;
+       }
+
        nvdimm_bus_lock(&ndns->dev);
        nd_pfn = nd_pfn_alloc(nd_region);
        pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
 
        NVDIMM_REVALIDATE_POISON,
 };
 
+enum nvdimm_claim_class {
+       NVDIMM_CCLASS_NONE,
+       NVDIMM_CCLASS_BTT,
+       NVDIMM_CCLASS_PFN,
+       NVDIMM_CCLASS_DAX,
+       NVDIMM_CCLASS_UNKNOWN,
+};
+
 struct nd_device_driver {
        struct device_driver drv;
        unsigned long type;
  * @force_raw: ignore other personalities for the namespace (e.g. btt)
  * @dev: device model node
  * @claim: when set a another personality has taken ownership of the namespace
+ * @claim_class: restrict claim type to a given class
  * @rw_bytes: access the raw namespace capacity with byte-aligned transfers
  */
 struct nd_namespace_common {
        int force_raw;
        struct device dev;
        struct device *claim;
+       enum nvdimm_claim_class claim_class;
        int (*rw_bytes)(struct nd_namespace_common *, resource_size_t offset,
                        void *buf, size_t size, int rw, unsigned long flags);
 };