/*
 * 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/module.h>
#include <linux/device.h>
#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/nd.h>
#include "nd-core.h"
#include "pmem.h"
#include "nd.h"

static void namespace_io_release(struct device *dev)
{
        struct nd_namespace_io *nsio = to_nd_namespace_io(dev);

        kfree(nsio);
}

static void namespace_pmem_release(struct device *dev)
{
        struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
        struct nd_region *nd_region = to_nd_region(dev->parent);

        if (nspm->id >= 0)
                ida_simple_remove(&nd_region->ns_ida, nspm->id);
        kfree(nspm->alt_name);
        kfree(nspm->uuid);
        kfree(nspm);
}

static void namespace_blk_release(struct device *dev)
{
        struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
        struct nd_region *nd_region = to_nd_region(dev->parent);

        if (nsblk->id >= 0)
                ida_simple_remove(&nd_region->ns_ida, nsblk->id);
        kfree(nsblk->alt_name);
        kfree(nsblk->uuid);
        kfree(nsblk->res);
        kfree(nsblk);
}

static const struct device_type namespace_io_device_type = {
        .name = "nd_namespace_io",
        .release = namespace_io_release,
};

static const struct device_type namespace_pmem_device_type = {
        .name = "nd_namespace_pmem",
        .release = namespace_pmem_release,
};

static const struct device_type namespace_blk_device_type = {
        .name = "nd_namespace_blk",
        .release = namespace_blk_release,
};

static bool is_namespace_pmem(const struct device *dev)
{
        return dev ? dev->type == &namespace_pmem_device_type : false;
}

static bool is_namespace_blk(const struct device *dev)
{
        return dev ? dev->type == &namespace_blk_device_type : false;
}

static bool is_namespace_io(const struct device *dev)
{
        return dev ? dev->type == &namespace_io_device_type : false;
}

static int is_uuid_busy(struct device *dev, void *data)
{
        u8 *uuid1 = data, *uuid2 = NULL;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                uuid2 = nspm->uuid;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                uuid2 = nsblk->uuid;
        } else if (is_nd_btt(dev)) {
                struct nd_btt *nd_btt = to_nd_btt(dev);

                uuid2 = nd_btt->uuid;
        } else if (is_nd_pfn(dev)) {
                struct nd_pfn *nd_pfn = to_nd_pfn(dev);

                uuid2 = nd_pfn->uuid;
        }

        if (uuid2 && memcmp(uuid1, uuid2, NSLABEL_UUID_LEN) == 0)
                return -EBUSY;

        return 0;
}

static int is_namespace_uuid_busy(struct device *dev, void *data)
{
        if (is_nd_region(dev))
                return device_for_each_child(dev, data, is_uuid_busy);
        return 0;
}

/**
 * nd_is_uuid_unique - verify that no other namespace has @uuid
 * @dev: any device on a nvdimm_bus
 * @uuid: uuid to check
 */
bool nd_is_uuid_unique(struct device *dev, u8 *uuid)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);

        if (!nvdimm_bus)
                return false;
        WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm_bus->dev));
        if (device_for_each_child(&nvdimm_bus->dev, uuid,
                                is_namespace_uuid_busy) != 0)
                return false;
        return true;
}

bool pmem_should_map_pages(struct device *dev)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        struct nd_namespace_io *nsio;

        if (!IS_ENABLED(CONFIG_ZONE_DEVICE))
                return false;

        if (!test_bit(ND_REGION_PAGEMAP, &nd_region->flags))
                return false;

        if (is_nd_pfn(dev) || is_nd_btt(dev))
                return false;

        nsio = to_nd_namespace_io(dev);
        if (region_intersects(nsio->res.start, resource_size(&nsio->res),
                                IORESOURCE_SYSTEM_RAM,
                                IORES_DESC_NONE) == REGION_MIXED)
                return false;

        return ARCH_MEMREMAP_PMEM == MEMREMAP_WB;
}
EXPORT_SYMBOL(pmem_should_map_pages);

unsigned int pmem_sector_size(struct nd_namespace_common *ndns)
{
        if (is_namespace_pmem(&ndns->dev)) {
                struct nd_namespace_pmem *nspm;

                nspm = to_nd_namespace_pmem(&ndns->dev);
                if (nspm->lbasize == 0 || nspm->lbasize == 512)
                        /* default */;
                else if (nspm->lbasize == 4096)
                        return 4096;
                else
                        dev_WARN(&ndns->dev, "unsupported sector size: %ld\n",
                                        nspm->lbasize);
        }

        /*
         * There is no namespace label (is_namespace_io()), or the label
         * indicates the default sector size.
         */
        return 512;
}
EXPORT_SYMBOL(pmem_sector_size);

const char *nvdimm_namespace_disk_name(struct nd_namespace_common *ndns,
                char *name)
{
        struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
        const char *suffix = NULL;

        if (ndns->claim && is_nd_btt(ndns->claim))
                suffix = "s";

        if (is_namespace_pmem(&ndns->dev) || is_namespace_io(&ndns->dev)) {
                int nsidx = 0;

                if (is_namespace_pmem(&ndns->dev)) {
                        struct nd_namespace_pmem *nspm;

                        nspm = to_nd_namespace_pmem(&ndns->dev);
                        nsidx = nspm->id;
                }

                if (nsidx)
                        sprintf(name, "pmem%d.%d%s", nd_region->id, nsidx,
                                        suffix ? suffix : "");
                else
                        sprintf(name, "pmem%d%s", nd_region->id,
                                        suffix ? suffix : "");
        } else if (is_namespace_blk(&ndns->dev)) {
                struct nd_namespace_blk *nsblk;

                nsblk = to_nd_namespace_blk(&ndns->dev);
                sprintf(name, "ndblk%d.%d%s", nd_region->id, nsblk->id,
                                suffix ? suffix : "");
        } else {
                return NULL;
        }

        return name;
}
EXPORT_SYMBOL(nvdimm_namespace_disk_name);

const u8 *nd_dev_to_uuid(struct device *dev)
{
        static const u8 null_uuid[16];

        if (!dev)
                return null_uuid;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                return nspm->uuid;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                return nsblk->uuid;
        } else
                return null_uuid;
}
EXPORT_SYMBOL(nd_dev_to_uuid);

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

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

static ssize_t __alt_name_store(struct device *dev, const char *buf,
                const size_t len)
{
        char *input, *pos, *alt_name, **ns_altname;
        ssize_t rc;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                ns_altname = &nspm->alt_name;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                ns_altname = &nsblk->alt_name;
        } else
                return -ENXIO;

        if (dev->driver || to_ndns(dev)->claim)
                return -EBUSY;

        input = kmemdup(buf, len + 1, GFP_KERNEL);
        if (!input)
                return -ENOMEM;

        input[len] = '\0';
        pos = strim(input);
        if (strlen(pos) + 1 > NSLABEL_NAME_LEN) {
                rc = -EINVAL;
                goto out;
        }

        alt_name = kzalloc(NSLABEL_NAME_LEN, GFP_KERNEL);
        if (!alt_name) {
                rc = -ENOMEM;
                goto out;
        }
        kfree(*ns_altname);
        *ns_altname = alt_name;
        sprintf(*ns_altname, "%s", pos);
        rc = len;

out:
        kfree(input);
        return rc;
}

static resource_size_t nd_namespace_blk_size(struct nd_namespace_blk *nsblk)
{
        struct nd_region *nd_region = to_nd_region(nsblk->common.dev.parent);
        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct nd_label_id label_id;
        resource_size_t size = 0;
        struct resource *res;

        if (!nsblk->uuid)
                return 0;
        nd_label_gen_id(&label_id, nsblk->uuid, NSLABEL_FLAG_LOCAL);
        for_each_dpa_resource(ndd, res)
                if (strcmp(res->name, label_id.id) == 0)
                        size += resource_size(res);
        return size;
}

static bool __nd_namespace_blk_validate(struct nd_namespace_blk *nsblk)
{
        struct nd_region *nd_region = to_nd_region(nsblk->common.dev.parent);
        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct nd_label_id label_id;
        struct resource *res;
        int count, i;

        if (!nsblk->uuid || !nsblk->lbasize || !ndd)
                return false;

        count = 0;
        nd_label_gen_id(&label_id, nsblk->uuid, NSLABEL_FLAG_LOCAL);
        for_each_dpa_resource(ndd, res) {
                if (strcmp(res->name, label_id.id) != 0)
                        continue;
                /*
                 * Resources with unacknowledged adjustments indicate a
                 * failure to update labels
                 */
                if (res->flags & DPA_RESOURCE_ADJUSTED)
                        return false;
                count++;
        }

        /* These values match after a successful label update */
        if (count != nsblk->num_resources)
                return false;

        for (i = 0; i < nsblk->num_resources; i++) {
                struct resource *found = NULL;

                for_each_dpa_resource(ndd, res)
                        if (res == nsblk->res[i]) {
                                found = res;
                                break;
                        }
                /* stale resource */
                if (!found)
                        return false;
        }

        return true;
}

resource_size_t nd_namespace_blk_validate(struct nd_namespace_blk *nsblk)
{
        resource_size_t size;

        nvdimm_bus_lock(&nsblk->common.dev);
        size = __nd_namespace_blk_validate(nsblk);
        nvdimm_bus_unlock(&nsblk->common.dev);

        return size;
}
EXPORT_SYMBOL(nd_namespace_blk_validate);


static int nd_namespace_label_update(struct nd_region *nd_region,
                struct device *dev)
{
        dev_WARN_ONCE(dev, dev->driver || to_ndns(dev)->claim,
                        "namespace must be idle during label update\n");
        if (dev->driver || to_ndns(dev)->claim)
                return 0;

        /*
         * Only allow label writes that will result in a valid namespace
         * or deletion of an existing namespace.
         */
        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
                resource_size_t size = resource_size(&nspm->nsio.res);

                if (size == 0 && nspm->uuid)
                        /* delete allocation */;
                else if (!nspm->uuid)
                        return 0;

                return nd_pmem_namespace_label_update(nd_region, nspm, size);
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
                resource_size_t size = nd_namespace_blk_size(nsblk);

                if (size == 0 && nsblk->uuid)
                        /* delete allocation */;
                else if (!nsblk->uuid || !nsblk->lbasize)
                        return 0;

                return nd_blk_namespace_label_update(nd_region, nsblk, size);
        } else
                return -ENXIO;
}

static ssize_t alt_name_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 = __alt_name_store(dev, buf, len);
        if (rc >= 0)
                rc = nd_namespace_label_update(nd_region, dev);
        dev_dbg(dev, "%s(%zd)\n", rc < 0 ? "fail " : "", rc);
        nvdimm_bus_unlock(dev);
        device_unlock(dev);

        return rc < 0 ? rc : len;
}

static ssize_t alt_name_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        char *ns_altname;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                ns_altname = nspm->alt_name;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                ns_altname = nsblk->alt_name;
        } else
                return -ENXIO;

        return sprintf(buf, "%s\n", ns_altname ? ns_altname : "");
}
static DEVICE_ATTR_RW(alt_name);

static int scan_free(struct nd_region *nd_region,
                struct nd_mapping *nd_mapping, struct nd_label_id *label_id,
                resource_size_t n)
{
        bool is_blk = strncmp(label_id->id, "blk", 3) == 0;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        int rc = 0;

        while (n) {
                struct resource *res, *last;
                resource_size_t new_start;

                last = NULL;
                for_each_dpa_resource(ndd, res)
                        if (strcmp(res->name, label_id->id) == 0)
                                last = res;
                res = last;
                if (!res)
                        return 0;

                if (n >= resource_size(res)) {
                        n -= resource_size(res);
                        nd_dbg_dpa(nd_region, ndd, res, "delete %d\n", rc);
                        nvdimm_free_dpa(ndd, res);
                        /* retry with last resource deleted */
                        continue;
                }

                /*
                 * Keep BLK allocations relegated to high DPA as much as
                 * possible
                 */
                if (is_blk)
                        new_start = res->start + n;
                else
                        new_start = res->start;

                rc = adjust_resource(res, new_start, resource_size(res) - n);
                if (rc == 0)
                        res->flags |= DPA_RESOURCE_ADJUSTED;
                nd_dbg_dpa(nd_region, ndd, res, "shrink %d\n", rc);
                break;
        }

        return rc;
}

/**
 * shrink_dpa_allocation - for each dimm in region free n bytes for label_id
 * @nd_region: the set of dimms to reclaim @n bytes from
 * @label_id: unique identifier for the namespace consuming this dpa range
 * @n: number of bytes per-dimm to release
 *
 * Assumes resources are ordered.  Starting from the end try to
 * adjust_resource() the allocation to @n, but if @n is larger than the
 * allocation delete it and find the 'new' last allocation in the label
 * set.
 */
static int shrink_dpa_allocation(struct nd_region *nd_region,
                struct nd_label_id *label_id, resource_size_t n)
{
        int i;

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

                rc = scan_free(nd_region, nd_mapping, label_id, n);
                if (rc)
                        return rc;
        }

        return 0;
}

static resource_size_t init_dpa_allocation(struct nd_label_id *label_id,
                struct nd_region *nd_region, struct nd_mapping *nd_mapping,
                resource_size_t n)
{
        bool is_blk = strncmp(label_id->id, "blk", 3) == 0;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        resource_size_t first_dpa;
        struct resource *res;
        int rc = 0;

        /* allocate blk from highest dpa first */
        if (is_blk)
                first_dpa = nd_mapping->start + nd_mapping->size - n;
        else
                first_dpa = nd_mapping->start;

        /* first resource allocation for this label-id or dimm */
        res = nvdimm_allocate_dpa(ndd, label_id, first_dpa, n);
        if (!res)
                rc = -EBUSY;

        nd_dbg_dpa(nd_region, ndd, res, "init %d\n", rc);
        return rc ? n : 0;
}


/**
 * space_valid() - validate free dpa space against constraints
 * @nd_region: hosting region of the free space
 * @ndd: dimm device data for debug
 * @label_id: namespace id to allocate space
 * @prev: potential allocation that precedes free space
 * @next: allocation that follows the given free space range
 * @exist: first allocation with same id in the mapping
 * @n: range that must satisfied for pmem allocations
 * @valid: free space range to validate
 *
 * BLK-space is valid as long as it does not precede a PMEM
 * allocation in a given region. PMEM-space must be contiguous
 * and adjacent to an existing existing allocation (if one
 * exists).  If reserving PMEM any space is valid.
 */
static void space_valid(struct nd_region *nd_region, struct nvdimm_drvdata *ndd,
                struct nd_label_id *label_id, struct resource *prev,
                struct resource *next, struct resource *exist,
                resource_size_t n, struct resource *valid)
{
        bool is_reserve = strcmp(label_id->id, "pmem-reserve") == 0;
        bool is_pmem = strncmp(label_id->id, "pmem", 4) == 0;

        if (valid->start >= valid->end)
                goto invalid;

        if (is_reserve)
                return;

        if (!is_pmem) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[0];
                struct nvdimm_bus *nvdimm_bus;
                struct blk_alloc_info info = {
                        .nd_mapping = nd_mapping,
                        .available = nd_mapping->size,
                        .res = valid,
                };

                WARN_ON(!is_nd_blk(&nd_region->dev));
                nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
                device_for_each_child(&nvdimm_bus->dev, &info, alias_dpa_busy);
                return;
        }

        /* allocation needs to be contiguous, so this is all or nothing */
        if (resource_size(valid) < n)
                goto invalid;

        /* we've got all the space we need and no existing allocation */
        if (!exist)
                return;

        /* allocation needs to be contiguous with the existing namespace */
        if (valid->start == exist->end + 1
                        || valid->end == exist->start - 1)
                return;

 invalid:
        /* truncate @valid size to 0 */
        valid->end = valid->start - 1;
}

enum alloc_loc {
        ALLOC_ERR = 0, ALLOC_BEFORE, ALLOC_MID, ALLOC_AFTER,
};

static resource_size_t scan_allocate(struct nd_region *nd_region,
                struct nd_mapping *nd_mapping, struct nd_label_id *label_id,
                resource_size_t n)
{
        resource_size_t mapping_end = nd_mapping->start + nd_mapping->size - 1;
        bool is_pmem = strncmp(label_id->id, "pmem", 4) == 0;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct resource *res, *exist = NULL, valid;
        const resource_size_t to_allocate = n;
        int first;

        for_each_dpa_resource(ndd, res)
                if (strcmp(label_id->id, res->name) == 0)
                        exist = res;

        valid.start = nd_mapping->start;
        valid.end = mapping_end;
        valid.name = "free space";
 retry:
        first = 0;
        for_each_dpa_resource(ndd, res) {
                struct resource *next = res->sibling, *new_res = NULL;
                resource_size_t allocate, available = 0;
                enum alloc_loc loc = ALLOC_ERR;
                const char *action;
                int rc = 0;

                /* ignore resources outside this nd_mapping */
                if (res->start > mapping_end)
                        continue;
                if (res->end < nd_mapping->start)
                        continue;

                /* space at the beginning of the mapping */
                if (!first++ && res->start > nd_mapping->start) {
                        valid.start = nd_mapping->start;
                        valid.end = res->start - 1;
                        space_valid(nd_region, ndd, label_id, NULL, next, exist,
                                        to_allocate, &valid);
                        available = resource_size(&valid);
                        if (available)
                                loc = ALLOC_BEFORE;
                }

                /* space between allocations */
                if (!loc && next) {
                        valid.start = res->start + resource_size(res);
                        valid.end = min(mapping_end, next->start - 1);
                        space_valid(nd_region, ndd, label_id, res, next, exist,
                                        to_allocate, &valid);
                        available = resource_size(&valid);
                        if (available)
                                loc = ALLOC_MID;
                }

                /* space at the end of the mapping */
                if (!loc && !next) {
                        valid.start = res->start + resource_size(res);
                        valid.end = mapping_end;
                        space_valid(nd_region, ndd, label_id, res, next, exist,
                                        to_allocate, &valid);
                        available = resource_size(&valid);
                        if (available)
                                loc = ALLOC_AFTER;
                }

                if (!loc || !available)
                        continue;
                allocate = min(available, n);
                switch (loc) {
                case ALLOC_BEFORE:
                        if (strcmp(res->name, label_id->id) == 0) {
                                /* adjust current resource up */
                                rc = adjust_resource(res, res->start - allocate,
                                                resource_size(res) + allocate);
                                action = "cur grow up";
                        } else
                                action = "allocate";
                        break;
                case ALLOC_MID:
                        if (strcmp(next->name, label_id->id) == 0) {
                                /* adjust next resource up */
                                rc = adjust_resource(next, next->start
                                                - allocate, resource_size(next)
                                                + allocate);
                                new_res = next;
                                action = "next grow up";
                        } else if (strcmp(res->name, label_id->id) == 0) {
                                action = "grow down";
                        } else
                                action = "allocate";
                        break;
                case ALLOC_AFTER:
                        if (strcmp(res->name, label_id->id) == 0)
                                action = "grow down";
                        else
                                action = "allocate";
                        break;
                default:
                        return n;
                }

                if (strcmp(action, "allocate") == 0) {
                        /* BLK allocate bottom up */
                        if (!is_pmem)
                                valid.start += available - allocate;

                        new_res = nvdimm_allocate_dpa(ndd, label_id,
                                        valid.start, allocate);
                        if (!new_res)
                                rc = -EBUSY;
                } else if (strcmp(action, "grow down") == 0) {
                        /* adjust current resource down */
                        rc = adjust_resource(res, res->start, resource_size(res)
                                        + allocate);
                        if (rc == 0)
                                res->flags |= DPA_RESOURCE_ADJUSTED;
                }

                if (!new_res)
                        new_res = res;

                nd_dbg_dpa(nd_region, ndd, new_res, "%s(%d) %d\n",
                                action, loc, rc);

                if (rc)
                        return n;

                n -= allocate;
                if (n) {
                        /*
                         * Retry scan with newly inserted resources.
                         * For example, if we did an ALLOC_BEFORE
                         * insertion there may also have been space
                         * available for an ALLOC_AFTER insertion, so we
                         * need to check this same resource again
                         */
                        goto retry;
                } else
                        return 0;
        }

        /*
         * If we allocated nothing in the BLK case it may be because we are in
         * an initial "pmem-reserve pass".  Only do an initial BLK allocation
         * when none of the DPA space is reserved.
         */
        if ((is_pmem || !ndd->dpa.child) && n == to_allocate)
                return init_dpa_allocation(label_id, nd_region, nd_mapping, n);
        return n;
}

static int merge_dpa(struct nd_region *nd_region,
                struct nd_mapping *nd_mapping, struct nd_label_id *label_id)
{
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct resource *res;

        if (strncmp("pmem", label_id->id, 4) == 0)
                return 0;
 retry:
        for_each_dpa_resource(ndd, res) {
                int rc;
                struct resource *next = res->sibling;
                resource_size_t end = res->start + resource_size(res);

                if (!next || strcmp(res->name, label_id->id) != 0
                                || strcmp(next->name, label_id->id) != 0
                                || end != next->start)
                        continue;
                end += resource_size(next);
                nvdimm_free_dpa(ndd, next);
                rc = adjust_resource(res, res->start, end - res->start);
                nd_dbg_dpa(nd_region, ndd, res, "merge %d\n", rc);
                if (rc)
                        return rc;
                res->flags |= DPA_RESOURCE_ADJUSTED;
                goto retry;
        }

        return 0;
}

int __reserve_free_pmem(struct device *dev, void *data)
{
        struct nvdimm *nvdimm = data;
        struct nd_region *nd_region;
        struct nd_label_id label_id;
        int i;

        if (!is_memory(dev))
                return 0;

        nd_region = to_nd_region(dev);
        if (nd_region->ndr_mappings == 0)
                return 0;

        memset(&label_id, 0, sizeof(label_id));
        strcat(label_id.id, "pmem-reserve");
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                resource_size_t n, rem = 0;

                if (nd_mapping->nvdimm != nvdimm)
                        continue;

                n = nd_pmem_available_dpa(nd_region, nd_mapping, &rem);
                if (n == 0)
                        return 0;
                rem = scan_allocate(nd_region, nd_mapping, &label_id, n);
                dev_WARN_ONCE(&nd_region->dev, rem,
                                "pmem reserve underrun: %#llx of %#llx bytes\n",
                                (unsigned long long) n - rem,
                                (unsigned long long) n);
                return rem ? -ENXIO : 0;
        }

        return 0;
}

void release_free_pmem(struct nvdimm_bus *nvdimm_bus,
                struct nd_mapping *nd_mapping)
{
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct resource *res, *_res;

        for_each_dpa_resource_safe(ndd, res, _res)
                if (strcmp(res->name, "pmem-reserve") == 0)
                        nvdimm_free_dpa(ndd, res);
}

static int reserve_free_pmem(struct nvdimm_bus *nvdimm_bus,
                struct nd_mapping *nd_mapping)
{
        struct nvdimm *nvdimm = nd_mapping->nvdimm;
        int rc;

        rc = device_for_each_child(&nvdimm_bus->dev, nvdimm,
                        __reserve_free_pmem);
        if (rc)
                release_free_pmem(nvdimm_bus, nd_mapping);
        return rc;
}

/**
 * grow_dpa_allocation - for each dimm allocate n bytes for @label_id
 * @nd_region: the set of dimms to allocate @n more bytes from
 * @label_id: unique identifier for the namespace consuming this dpa range
 * @n: number of bytes per-dimm to add to the existing allocation
 *
 * Assumes resources are ordered.  For BLK regions, first consume
 * BLK-only available DPA free space, then consume PMEM-aliased DPA
 * space starting at the highest DPA.  For PMEM regions start
 * allocations from the start of an interleave set and end at the first
 * BLK allocation or the end of the interleave set, whichever comes
 * first.
 */
static int grow_dpa_allocation(struct nd_region *nd_region,
                struct nd_label_id *label_id, resource_size_t n)
{
        struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
        bool is_pmem = strncmp(label_id->id, "pmem", 4) == 0;
        int i;

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                resource_size_t rem = n;
                int rc, j;

                /*
                 * In the BLK case try once with all unallocated PMEM
                 * reserved, and once without
                 */
                for (j = is_pmem; j < 2; j++) {
                        bool blk_only = j == 0;

                        if (blk_only) {
                                rc = reserve_free_pmem(nvdimm_bus, nd_mapping);
                                if (rc)
                                        return rc;
                        }
                        rem = scan_allocate(nd_region, nd_mapping,
                                        label_id, rem);
                        if (blk_only)
                                release_free_pmem(nvdimm_bus, nd_mapping);

                        /* try again and allow encroachments into PMEM */
                        if (rem == 0)
                                break;
                }

                dev_WARN_ONCE(&nd_region->dev, rem,
                                "allocation underrun: %#llx of %#llx bytes\n",
                                (unsigned long long) n - rem,
                                (unsigned long long) n);
                if (rem)
                        return -ENXIO;

                rc = merge_dpa(nd_region, nd_mapping, label_id);
                if (rc)
                        return rc;
        }

        return 0;
}

static void nd_namespace_pmem_set_resource(struct nd_region *nd_region,
                struct nd_namespace_pmem *nspm, resource_size_t size)
{
        struct resource *res = &nspm->nsio.res;
        resource_size_t offset = 0;

        if (size && !nspm->uuid) {
                WARN_ON_ONCE(1);
                size = 0;
        }

        if (size && nspm->uuid) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[0];
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct nd_label_id label_id;
                struct resource *res;

                if (!ndd) {
                        size = 0;
                        goto out;
                }

                nd_label_gen_id(&label_id, nspm->uuid, 0);

                /* calculate a spa offset from the dpa allocation offset */
                for_each_dpa_resource(ndd, res)
                        if (strcmp(res->name, label_id.id) == 0) {
                                offset = (res->start - nd_mapping->start)
                                        * nd_region->ndr_mappings;
                                goto out;
                        }

                WARN_ON_ONCE(1);
                size = 0;
        }

 out:
        res->start = nd_region->ndr_start + offset;
        res->end = res->start + size - 1;
}

static bool uuid_not_set(const u8 *uuid, struct device *dev, const char *where)
{
        if (!uuid) {
                dev_dbg(dev, "%s: uuid not set\n", where);
                return true;
        }
        return false;
}

static ssize_t __size_store(struct device *dev, unsigned long long val)
{
        resource_size_t allocated = 0, available = 0;
        struct nd_region *nd_region = to_nd_region(dev->parent);
        struct nd_namespace_common *ndns = to_ndns(dev);
        struct nd_mapping *nd_mapping;
        struct nvdimm_drvdata *ndd;
        struct nd_label_id label_id;
        u32 flags = 0, remainder;
        int rc, i, id = -1;
        u8 *uuid = NULL;

        if (dev->driver || ndns->claim)
                return -EBUSY;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                uuid = nspm->uuid;
                id = nspm->id;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                uuid = nsblk->uuid;
                flags = NSLABEL_FLAG_LOCAL;
                id = nsblk->id;

        }

        /*
         * We need a uuid for the allocation-label and dimm(s) on which
         * to store the label.
         */
        if (uuid_not_set(uuid, dev, __func__))
                return -ENXIO;
        if (nd_region->ndr_mappings == 0) {
                dev_dbg(dev, "not associated with dimm(s)\n");
                return -ENXIO;
        }

        div_u64_rem(val, SZ_4K * nd_region->ndr_mappings, &remainder);
        if (remainder) {
                dev_dbg(dev, "%llu is not %dK aligned\n", val,
                                (SZ_4K * nd_region->ndr_mappings) / SZ_1K);
                return -EINVAL;
        }

        nd_label_gen_id(&label_id, uuid, flags);
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                nd_mapping = &nd_region->mapping[i];
                ndd = to_ndd(nd_mapping);

                /*
                 * All dimms in an interleave set, or the base dimm for a blk
                 * region, need to be enabled for the size to be changed.
                 */
                if (!ndd)
                        return -ENXIO;

                allocated += nvdimm_allocated_dpa(ndd, &label_id);
        }
        available = nd_region_allocatable_dpa(nd_region);

        if (val > available + allocated)
                return -ENOSPC;

        if (val == allocated)
                return 0;

        val = div_u64(val, nd_region->ndr_mappings);
        allocated = div_u64(allocated, nd_region->ndr_mappings);
        if (val < allocated)
                rc = shrink_dpa_allocation(nd_region, &label_id,
                                allocated - val);
        else
                rc = grow_dpa_allocation(nd_region, &label_id, val - allocated);

        if (rc)
                return rc;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                nd_namespace_pmem_set_resource(nd_region, nspm,
                                val * nd_region->ndr_mappings);
        }

        /*
         * Try to delete the namespace if we deleted all of its
         * allocation, this is not the seed or 0th device for the
         * region, and it is not actively claimed by a btt, pfn, or dax
         * instance.
         */
        if (val == 0 && id != 0 && nd_region->ns_seed != dev && !ndns->claim)
                nd_device_unregister(dev, ND_ASYNC);

        return rc;
}

static ssize_t size_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t len)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        unsigned long long val;
        u8 **uuid = NULL;
        int rc;

        rc = kstrtoull(buf, 0, &val);
        if (rc)
                return rc;

        device_lock(dev);
        nvdimm_bus_lock(dev);
        wait_nvdimm_bus_probe_idle(dev);
        rc = __size_store(dev, val);
        if (rc >= 0)
                rc = nd_namespace_label_update(nd_region, dev);

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                uuid = &nspm->uuid;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                uuid = &nsblk->uuid;
        }

        if (rc == 0 && val == 0 && uuid) {
                /* setting size zero == 'delete namespace' */
                kfree(*uuid);
                *uuid = NULL;
        }

        dev_dbg(dev, "%llx %s (%d)\n", val, rc < 0 ? "fail" : "success", rc);

        nvdimm_bus_unlock(dev);
        device_unlock(dev);

        return rc < 0 ? rc : len;
}

resource_size_t __nvdimm_namespace_capacity(struct nd_namespace_common *ndns)
{
        struct device *dev = &ndns->dev;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                return resource_size(&nspm->nsio.res);
        } else if (is_namespace_blk(dev)) {
                return nd_namespace_blk_size(to_nd_namespace_blk(dev));
        } else if (is_namespace_io(dev)) {
                struct nd_namespace_io *nsio = to_nd_namespace_io(dev);

                return resource_size(&nsio->res);
        } else
                WARN_ONCE(1, "unknown namespace type\n");
        return 0;
}

resource_size_t nvdimm_namespace_capacity(struct nd_namespace_common *ndns)
{
        resource_size_t size;

        nvdimm_bus_lock(&ndns->dev);
        size = __nvdimm_namespace_capacity(ndns);
        nvdimm_bus_unlock(&ndns->dev);

        return size;
}
EXPORT_SYMBOL(nvdimm_namespace_capacity);

bool nvdimm_namespace_locked(struct nd_namespace_common *ndns)
{
        int i;
        bool locked = false;
        struct device *dev = &ndns->dev;
        struct nd_region *nd_region = to_nd_region(dev->parent);

        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 (test_bit(NDD_LOCKED, &nvdimm->flags)) {
                        dev_dbg(dev, "%s locked\n", nvdimm_name(nvdimm));
                        locked = true;
                }
        }
        return locked;
}
EXPORT_SYMBOL(nvdimm_namespace_locked);

static ssize_t size_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%llu\n", (unsigned long long)
                        nvdimm_namespace_capacity(to_ndns(dev)));
}
static DEVICE_ATTR(size, 0444, size_show, size_store);

static u8 *namespace_to_uuid(struct device *dev)
{
        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                return nspm->uuid;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                return nsblk->uuid;
        } else
                return ERR_PTR(-ENXIO);
}

static ssize_t uuid_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        u8 *uuid = namespace_to_uuid(dev);

        if (IS_ERR(uuid))
                return PTR_ERR(uuid);
        if (uuid)
                return sprintf(buf, "%pUb\n", uuid);
        return sprintf(buf, "\n");
}

/**
 * namespace_update_uuid - check for a unique uuid and whether we're "renaming"
 * @nd_region: parent region so we can updates all dimms in the set
 * @dev: namespace type for generating label_id
 * @new_uuid: incoming uuid
 * @old_uuid: reference to the uuid storage location in the namespace object
 */
static int namespace_update_uuid(struct nd_region *nd_region,
                struct device *dev, u8 *new_uuid, u8 **old_uuid)
{
        u32 flags = is_namespace_blk(dev) ? NSLABEL_FLAG_LOCAL : 0;
        struct nd_label_id old_label_id;
        struct nd_label_id new_label_id;
        int i;

        if (!nd_is_uuid_unique(dev, new_uuid))
                return -EINVAL;

        if (*old_uuid == NULL)
                goto out;

        /*
         * If we've already written a label with this uuid, then it's
         * too late to rename because we can't reliably update the uuid
         * without losing the old namespace.  Userspace must delete this
         * namespace to abandon the old uuid.
         */
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];

                /*
                 * This check by itself is sufficient because old_uuid
                 * would be NULL above if this uuid did not exist in the
                 * currently written set.
                 *
                 * FIXME: can we delete uuid with zero dpa allocated?
                 */
                if (list_empty(&nd_mapping->labels))
                        return -EBUSY;
        }

        nd_label_gen_id(&old_label_id, *old_uuid, flags);
        nd_label_gen_id(&new_label_id, new_uuid, flags);
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct resource *res;

                for_each_dpa_resource(ndd, res)
                        if (strcmp(res->name, old_label_id.id) == 0)
                                sprintf((void *) res->name, "%s",
                                                new_label_id.id);
        }
        kfree(*old_uuid);
 out:
        *old_uuid = new_uuid;
        return 0;
}

static ssize_t uuid_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t len)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        u8 *uuid = NULL;
        ssize_t rc = 0;
        u8 **ns_uuid;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                ns_uuid = &nspm->uuid;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                ns_uuid = &nsblk->uuid;
        } else
                return -ENXIO;

        device_lock(dev);
        nvdimm_bus_lock(dev);
        wait_nvdimm_bus_probe_idle(dev);
        if (to_ndns(dev)->claim)
                rc = -EBUSY;
        if (rc >= 0)
                rc = nd_uuid_store(dev, &uuid, buf, len);
        if (rc >= 0)
                rc = namespace_update_uuid(nd_region, dev, uuid, ns_uuid);
        if (rc >= 0)
                rc = nd_namespace_label_update(nd_region, dev);
        else
                kfree(uuid);
        dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
                        buf[len - 1] == '\n' ? "" : "\n");
        nvdimm_bus_unlock(dev);
        device_unlock(dev);

        return rc < 0 ? rc : len;
}
static DEVICE_ATTR_RW(uuid);

static ssize_t resource_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct resource *res;

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                res = &nspm->nsio.res;
        } else if (is_namespace_io(dev)) {
                struct nd_namespace_io *nsio = to_nd_namespace_io(dev);

                res = &nsio->res;
        } else
                return -ENXIO;

        /* no address to convey if the namespace has no allocation */
        if (resource_size(res) == 0)
                return -ENXIO;
        return sprintf(buf, "%#llx\n", (unsigned long long) res->start);
}
static DEVICE_ATTR_RO(resource);

static const unsigned long blk_lbasize_supported[] = { 512, 520, 528,
        4096, 4104, 4160, 4224, 0 };

static const unsigned long pmem_lbasize_supported[] = { 512, 4096, 0 };

static ssize_t sector_size_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                return nd_size_select_show(nsblk->lbasize,
                                blk_lbasize_supported, buf);
        }

        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                return nd_size_select_show(nspm->lbasize,
                                pmem_lbasize_supported, buf);
        }
        return -ENXIO;
}

static ssize_t sector_size_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t len)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        const unsigned long *supported;
        unsigned long *lbasize;
        ssize_t rc = 0;

        if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                lbasize = &nsblk->lbasize;
                supported = blk_lbasize_supported;
        } else if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                lbasize = &nspm->lbasize;
                supported = pmem_lbasize_supported;
        } else
                return -ENXIO;

        device_lock(dev);
        nvdimm_bus_lock(dev);
        if (to_ndns(dev)->claim)
                rc = -EBUSY;
        if (rc >= 0)
                rc = nd_size_select_store(dev, buf, lbasize, supported);
        if (rc >= 0)
                rc = nd_namespace_label_update(nd_region, dev);
        dev_dbg(dev, "result: %zd %s: %s%s", rc, rc < 0 ? "tried" : "wrote",
                        buf, buf[len - 1] == '\n' ? "" : "\n");
        nvdimm_bus_unlock(dev);
        device_unlock(dev);

        return rc ? rc : len;
}
static DEVICE_ATTR_RW(sector_size);

static ssize_t dpa_extents_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        struct nd_label_id label_id;
        int count = 0, i;
        u8 *uuid = NULL;
        u32 flags = 0;

        nvdimm_bus_lock(dev);
        if (is_namespace_pmem(dev)) {
                struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);

                uuid = nspm->uuid;
                flags = 0;
        } else if (is_namespace_blk(dev)) {
                struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);

                uuid = nsblk->uuid;
                flags = NSLABEL_FLAG_LOCAL;
        }

        if (!uuid)
                goto out;

        nd_label_gen_id(&label_id, uuid, flags);
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct resource *res;

                for_each_dpa_resource(ndd, res)
                        if (strcmp(res->name, label_id.id) == 0)
                                count++;
        }
 out:
        nvdimm_bus_unlock(dev);

        return sprintf(buf, "%d\n", count);
}
static DEVICE_ATTR_RO(dpa_extents);

static int btt_claim_class(struct device *dev)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        int i, loop_bitmask = 0;

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct nd_namespace_index *nsindex;

                /*
                 * If any of the DIMMs do not support labels the only
                 * possible BTT format is v1.
                 */
                if (!ndd) {
                        loop_bitmask = 0;
                        break;
                }

                nsindex = to_namespace_index(ndd, ndd->ns_current);
                if (nsindex == NULL)
                        loop_bitmask |= 1;
                else {
                        /* check whether existing labels are v1.1 or v1.2 */
                        if (__le16_to_cpu(nsindex->major) == 1
                                        && __le16_to_cpu(nsindex->minor) == 1)
                                loop_bitmask |= 2;
                        else
                                loop_bitmask |= 4;
                }
        }
        /*
         * If nsindex is null loop_bitmask's bit 0 will be set, and if an index
         * block is found, a v1.1 label for any mapping will set bit 1, and a
         * v1.2 label will set bit 2.
         *
         * At the end of the loop, at most one of the three bits must be set.
         * If multiple bits were set, it means the different mappings disagree
         * about their labels, and this must be cleaned up first.
         *
         * If all the label index blocks are found to agree, nsindex of NULL
         * implies labels haven't been initialized yet, and when they will,
         * they will be of the 1.2 format, so we can assume BTT2.0
         *
         * If 1.1 labels are found, we enforce BTT1.1, and if 1.2 labels are
         * found, we enforce BTT2.0
         *
         * If the loop was never entered, default to BTT1.1 (legacy namespaces)
         */
        switch (loop_bitmask) {
        case 0:
        case 2:
                return NVDIMM_CCLASS_BTT;
        case 1:
        case 4:
                return NVDIMM_CCLASS_BTT2;
        default:
                return -ENXIO;
        }
}

static ssize_t holder_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct nd_namespace_common *ndns = to_ndns(dev);
        ssize_t rc;

        device_lock(dev);
        rc = sprintf(buf, "%s\n", ndns->claim ? dev_name(ndns->claim) : "");
        device_unlock(dev);

        return rc;
}
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 = btt_claim_class(dev);
        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;

        /* btt_claim_class() could've returned an error */
        if (ndns->claim_class < 0)
                return ndns->claim_class;

        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(%zd)\n", 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) ||
                        (ndns->claim_class == NVDIMM_CCLASS_BTT2))
                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)
{
        struct nd_namespace_common *ndns = to_ndns(dev);
        struct device *claim;
        char *mode;
        ssize_t rc;

        device_lock(dev);
        claim = ndns->claim;
        if (claim && is_nd_btt(claim))
                mode = "safe";
        else if (claim && is_nd_pfn(claim))
                mode = "memory";
        else if (claim && is_nd_dax(claim))
                mode = "dax";
        else if (!claim && pmem_should_map_pages(dev))
                mode = "memory";
        else
                mode = "raw";
        rc = sprintf(buf, "%s\n", mode);
        device_unlock(dev);

        return rc;
}
static DEVICE_ATTR_RO(mode);

static ssize_t force_raw_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t len)
{
        bool force_raw;
        int rc = strtobool(buf, &force_raw);

        if (rc)
                return rc;

        to_ndns(dev)->force_raw = force_raw;
        return len;
}

static ssize_t force_raw_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", to_ndns(dev)->force_raw);
}
static DEVICE_ATTR_RW(force_raw);

static struct attribute *nd_namespace_attributes[] = {
        &dev_attr_nstype.attr,
        &dev_attr_size.attr,
        &dev_attr_mode.attr,
        &dev_attr_uuid.attr,
        &dev_attr_holder.attr,
        &dev_attr_resource.attr,
        &dev_attr_alt_name.attr,
        &dev_attr_force_raw.attr,
        &dev_attr_sector_size.attr,
        &dev_attr_dpa_extents.attr,
        &dev_attr_holder_class.attr,
        NULL,
};

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

        if (a == &dev_attr_resource.attr) {
                if (is_namespace_blk(dev))
                        return 0;
                return 0400;
        }

        if (is_namespace_pmem(dev) || is_namespace_blk(dev)) {
                if (a == &dev_attr_size.attr)
                        return 0644;

                return a->mode;
        }

        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;

        return 0;
}

static struct attribute_group nd_namespace_attribute_group = {
        .attrs = nd_namespace_attributes,
        .is_visible = namespace_visible,
};

static const struct attribute_group *nd_namespace_attribute_groups[] = {
        &nd_device_attribute_group,
        &nd_namespace_attribute_group,
        &nd_numa_attribute_group,
        NULL,
};

struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev)
{
        struct nd_btt *nd_btt = is_nd_btt(dev) ? to_nd_btt(dev) : NULL;
        struct nd_pfn *nd_pfn = is_nd_pfn(dev) ? to_nd_pfn(dev) : NULL;
        struct nd_dax *nd_dax = is_nd_dax(dev) ? to_nd_dax(dev) : NULL;
        struct nd_namespace_common *ndns = NULL;
        resource_size_t size;

        if (nd_btt || nd_pfn || nd_dax) {
                if (nd_btt)
                        ndns = nd_btt->ndns;
                else if (nd_pfn)
                        ndns = nd_pfn->ndns;
                else if (nd_dax)
                        ndns = nd_dax->nd_pfn.ndns;

                if (!ndns)
                        return ERR_PTR(-ENODEV);

                /*
                 * Flush any in-progess probes / removals in the driver
                 * for the raw personality of this namespace.
                 */
                device_lock(&ndns->dev);
                device_unlock(&ndns->dev);
                if (ndns->dev.driver) {
                        dev_dbg(&ndns->dev, "is active, can't bind %s\n",
                                        dev_name(dev));
                        return ERR_PTR(-EBUSY);
                }
                if (dev_WARN_ONCE(&ndns->dev, ndns->claim != dev,
                                        "host (%s) vs claim (%s) mismatch\n",
                                        dev_name(dev),
                                        dev_name(ndns->claim)))
                        return ERR_PTR(-ENXIO);
        } else {
                ndns = to_ndns(dev);
                if (ndns->claim) {
                        dev_dbg(dev, "claimed by %s, failing probe\n",
                                dev_name(ndns->claim));

                        return ERR_PTR(-ENXIO);
                }
        }

        if (nvdimm_namespace_locked(ndns))
                return ERR_PTR(-EACCES);

        size = nvdimm_namespace_capacity(ndns);
        if (size < ND_MIN_NAMESPACE_SIZE) {
                dev_dbg(&ndns->dev, "%pa, too small must be at least %#x\n",
                                &size, ND_MIN_NAMESPACE_SIZE);
                return ERR_PTR(-ENODEV);
        }

        if (is_namespace_pmem(&ndns->dev)) {
                struct nd_namespace_pmem *nspm;

                nspm = to_nd_namespace_pmem(&ndns->dev);
                if (uuid_not_set(nspm->uuid, &ndns->dev, __func__))
                        return ERR_PTR(-ENODEV);
        } else if (is_namespace_blk(&ndns->dev)) {
                struct nd_namespace_blk *nsblk;

                nsblk = to_nd_namespace_blk(&ndns->dev);
                if (uuid_not_set(nsblk->uuid, &ndns->dev, __func__))
                        return ERR_PTR(-ENODEV);
                if (!nsblk->lbasize) {
                        dev_dbg(&ndns->dev, "sector size not set\n");
                        return ERR_PTR(-ENODEV);
                }
                if (!nd_namespace_blk_validate(nsblk))
                        return ERR_PTR(-ENODEV);
        }

        return ndns;
}
EXPORT_SYMBOL(nvdimm_namespace_common_probe);

static struct device **create_namespace_io(struct nd_region *nd_region)
{
        struct nd_namespace_io *nsio;
        struct device *dev, **devs;
        struct resource *res;

        nsio = kzalloc(sizeof(*nsio), GFP_KERNEL);
        if (!nsio)
                return NULL;

        devs = kcalloc(2, sizeof(struct device *), GFP_KERNEL);
        if (!devs) {
                kfree(nsio);
                return NULL;
        }

        dev = &nsio->common.dev;
        dev->type = &namespace_io_device_type;
        dev->parent = &nd_region->dev;
        res = &nsio->res;
        res->name = dev_name(&nd_region->dev);
        res->flags = IORESOURCE_MEM;
        res->start = nd_region->ndr_start;
        res->end = res->start + nd_region->ndr_size - 1;

        devs[0] = dev;
        return devs;
}

static bool has_uuid_at_pos(struct nd_region *nd_region, u8 *uuid,
                u64 cookie, u16 pos)
{
        struct nd_namespace_label *found = NULL;
        int i;

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                struct nd_interleave_set *nd_set = nd_region->nd_set;
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct nd_label_ent *label_ent;
                bool found_uuid = false;

                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
                        struct nd_namespace_label *nd_label = label_ent->label;
                        u16 position, nlabel;
                        u64 isetcookie;

                        if (!nd_label)
                                continue;
                        isetcookie = __le64_to_cpu(nd_label->isetcookie);
                        position = __le16_to_cpu(nd_label->position);
                        nlabel = __le16_to_cpu(nd_label->nlabel);

                        if (isetcookie != cookie)
                                continue;

                        if (memcmp(nd_label->uuid, uuid, NSLABEL_UUID_LEN) != 0)
                                continue;

                        if (namespace_label_has(ndd, type_guid)
                                        && !guid_equal(&nd_set->type_guid,
                                                &nd_label->type_guid)) {
                                dev_dbg(ndd->dev, "expect type_guid %pUb got %pUb\n",
                                                nd_set->type_guid.b,
                                                nd_label->type_guid.b);
                                continue;
                        }

                        if (found_uuid) {
                                dev_dbg(ndd->dev, "duplicate entry for uuid\n");
                                return false;
                        }
                        found_uuid = true;
                        if (nlabel != nd_region->ndr_mappings)
                                continue;
                        if (position != pos)
                                continue;
                        found = nd_label;
                        break;
                }
                if (found)
                        break;
        }
        return found != NULL;
}

static int select_pmem_id(struct nd_region *nd_region, u8 *pmem_id)
{
        int i;

        if (!pmem_id)
                return -ENODEV;

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct nd_namespace_label *nd_label = NULL;
                u64 hw_start, hw_end, pmem_start, pmem_end;
                struct nd_label_ent *label_ent;

                lockdep_assert_held(&nd_mapping->lock);
                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
                        nd_label = label_ent->label;
                        if (!nd_label)
                                continue;
                        if (memcmp(nd_label->uuid, pmem_id, NSLABEL_UUID_LEN) == 0)
                                break;
                        nd_label = NULL;
                }

                if (!nd_label) {
                        WARN_ON(1);
                        return -EINVAL;
                }

                /*
                 * Check that this label is compliant with the dpa
                 * range published in NFIT
                 */
                hw_start = nd_mapping->start;
                hw_end = hw_start + nd_mapping->size;
                pmem_start = __le64_to_cpu(nd_label->dpa);
                pmem_end = pmem_start + __le64_to_cpu(nd_label->rawsize);
                if (pmem_start >= hw_start && pmem_start < hw_end
                                && pmem_end <= hw_end && pmem_end > hw_start)
                        /* pass */;
                else {
                        dev_dbg(&nd_region->dev, "%s invalid label for %pUb\n",
                                        dev_name(ndd->dev), nd_label->uuid);
                        return -EINVAL;
                }

                /* move recently validated label to the front of the list */
                list_move(&label_ent->list, &nd_mapping->labels);
        }
        return 0;
}

/**
 * create_namespace_pmem - validate interleave set labelling, retrieve label0
 * @nd_region: region with mappings to validate
 * @nspm: target namespace to create
 * @nd_label: target pmem namespace label to evaluate
 */
static struct device *create_namespace_pmem(struct nd_region *nd_region,
                struct nd_namespace_index *nsindex,
                struct nd_namespace_label *nd_label)
{
        u64 cookie = nd_region_interleave_set_cookie(nd_region, nsindex);
        u64 altcookie = nd_region_interleave_set_altcookie(nd_region);
        struct nd_label_ent *label_ent;
        struct nd_namespace_pmem *nspm;
        struct nd_mapping *nd_mapping;
        resource_size_t size = 0;
        struct resource *res;
        struct device *dev;
        int rc = 0;
        u16 i;

        if (cookie == 0) {
                dev_dbg(&nd_region->dev, "invalid interleave-set-cookie\n");
                return ERR_PTR(-ENXIO);
        }

        if (__le64_to_cpu(nd_label->isetcookie) != cookie) {
                dev_dbg(&nd_region->dev, "invalid cookie in label: %pUb\n",
                                nd_label->uuid);
                if (__le64_to_cpu(nd_label->isetcookie) != altcookie)
                        return ERR_PTR(-EAGAIN);

                dev_dbg(&nd_region->dev, "valid altcookie in label: %pUb\n",
                                nd_label->uuid);
        }

        nspm = kzalloc(sizeof(*nspm), GFP_KERNEL);
        if (!nspm)
                return ERR_PTR(-ENOMEM);

        nspm->id = -1;
        dev = &nspm->nsio.common.dev;
        dev->type = &namespace_pmem_device_type;
        dev->parent = &nd_region->dev;
        res = &nspm->nsio.res;
        res->name = dev_name(&nd_region->dev);
        res->flags = IORESOURCE_MEM;

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                if (has_uuid_at_pos(nd_region, nd_label->uuid, cookie, i))
                        continue;
                if (has_uuid_at_pos(nd_region, nd_label->uuid, altcookie, i))
                        continue;
                break;
        }

        if (i < nd_region->ndr_mappings) {
                struct nvdimm *nvdimm = nd_region->mapping[i].nvdimm;

                /*
                 * Give up if we don't find an instance of a uuid at each
                 * position (from 0 to nd_region->ndr_mappings - 1), or if we
                 * find a dimm with two instances of the same uuid.
                 */
                dev_err(&nd_region->dev, "%s missing label for %pUb\n",
                                nvdimm_name(nvdimm), nd_label->uuid);
                rc = -EINVAL;
                goto err;
        }

        /*
         * Fix up each mapping's 'labels' to have the validated pmem label for
         * that position at labels[0], and NULL at labels[1].  In the process,
         * check that the namespace aligns with interleave-set.  We know
         * that it does not overlap with any blk namespaces by virtue of
         * the dimm being enabled (i.e. nd_label_reserve_dpa()
         * succeeded).
         */
        rc = select_pmem_id(nd_region, nd_label->uuid);
        if (rc)
                goto err;

        /* 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,
                                typeof(*label_ent), list);
                label0 = label_ent ? label_ent->label : 0;

                if (!label0) {
                        WARN_ON(1);
                        continue;
                }

                size += __le64_to_cpu(label0->rawsize);
                if (__le16_to_cpu(label0->position) != 0)
                        continue;
                WARN_ON(nspm->alt_name || nspm->uuid);
                nspm->alt_name = kmemdup((void __force *) label0->name,
                                NSLABEL_NAME_LEN, GFP_KERNEL);
                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) {
                rc = -ENOMEM;
                goto err;
        }

        nd_namespace_pmem_set_resource(nd_region, nspm, size);

        return dev;
 err:
        namespace_pmem_release(dev);
        switch (rc) {
        case -EINVAL:
                dev_dbg(&nd_region->dev, "invalid label(s)\n");
                break;
        case -ENODEV:
                dev_dbg(&nd_region->dev, "label not found\n");
                break;
        default:
                dev_dbg(&nd_region->dev, "unexpected err: %d\n", rc);
                break;
        }
        return ERR_PTR(rc);
}

struct resource *nsblk_add_resource(struct nd_region *nd_region,
                struct nvdimm_drvdata *ndd, struct nd_namespace_blk *nsblk,
                resource_size_t start)
{
        struct nd_label_id label_id;
        struct resource *res;

        nd_label_gen_id(&label_id, nsblk->uuid, NSLABEL_FLAG_LOCAL);
        res = krealloc(nsblk->res,
                        sizeof(void *) * (nsblk->num_resources + 1),
                        GFP_KERNEL);
        if (!res)
                return NULL;
        nsblk->res = (struct resource **) res;
        for_each_dpa_resource(ndd, res)
                if (strcmp(res->name, label_id.id) == 0
                                && res->start == start) {
                        nsblk->res[nsblk->num_resources++] = res;
                        return res;
                }
        return NULL;
}

static struct device *nd_namespace_blk_create(struct nd_region *nd_region)
{
        struct nd_namespace_blk *nsblk;
        struct device *dev;

        if (!is_nd_blk(&nd_region->dev))
                return NULL;

        nsblk = kzalloc(sizeof(*nsblk), GFP_KERNEL);
        if (!nsblk)
                return NULL;

        dev = &nsblk->common.dev;
        dev->type = &namespace_blk_device_type;
        nsblk->id = ida_simple_get(&nd_region->ns_ida, 0, 0, GFP_KERNEL);
        if (nsblk->id < 0) {
                kfree(nsblk);
                return NULL;
        }
        dev_set_name(dev, "namespace%d.%d", nd_region->id, nsblk->id);
        dev->parent = &nd_region->dev;
        dev->groups = nd_namespace_attribute_groups;

        return &nsblk->common.dev;
}

static struct device *nd_namespace_pmem_create(struct nd_region *nd_region)
{
        struct nd_namespace_pmem *nspm;
        struct resource *res;
        struct device *dev;

        if (!is_memory(&nd_region->dev))
                return NULL;

        nspm = kzalloc(sizeof(*nspm), GFP_KERNEL);
        if (!nspm)
                return NULL;

        dev = &nspm->nsio.common.dev;
        dev->type = &namespace_pmem_device_type;
        dev->parent = &nd_region->dev;
        res = &nspm->nsio.res;
        res->name = dev_name(&nd_region->dev);
        res->flags = IORESOURCE_MEM;

        nspm->id = ida_simple_get(&nd_region->ns_ida, 0, 0, GFP_KERNEL);
        if (nspm->id < 0) {
                kfree(nspm);
                return NULL;
        }
        dev_set_name(dev, "namespace%d.%d", nd_region->id, nspm->id);
        dev->parent = &nd_region->dev;
        dev->groups = nd_namespace_attribute_groups;
        nd_namespace_pmem_set_resource(nd_region, nspm, 0);

        return dev;
}

void nd_region_create_ns_seed(struct nd_region *nd_region)
{
        WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));

        if (nd_region_to_nstype(nd_region) == ND_DEVICE_NAMESPACE_IO)
                return;

        if (is_nd_blk(&nd_region->dev))
                nd_region->ns_seed = nd_namespace_blk_create(nd_region);
        else
                nd_region->ns_seed = nd_namespace_pmem_create(nd_region);

        /*
         * Seed creation failures are not fatal, provisioning is simply
         * disabled until memory becomes available
         */
        if (!nd_region->ns_seed)
                dev_err(&nd_region->dev, "failed to create %s namespace\n",
                                is_nd_blk(&nd_region->dev) ? "blk" : "pmem");
        else
                nd_device_register(nd_region->ns_seed);
}

void nd_region_create_dax_seed(struct nd_region *nd_region)
{
        WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
        nd_region->dax_seed = nd_dax_create(nd_region);
        /*
         * Seed creation failures are not fatal, provisioning is simply
         * disabled until memory becomes available
         */
        if (!nd_region->dax_seed)
                dev_err(&nd_region->dev, "failed to create dax namespace\n");
}

void nd_region_create_pfn_seed(struct nd_region *nd_region)
{
        WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
        nd_region->pfn_seed = nd_pfn_create(nd_region);
        /*
         * Seed creation failures are not fatal, provisioning is simply
         * disabled until memory becomes available
         */
        if (!nd_region->pfn_seed)
                dev_err(&nd_region->dev, "failed to create pfn namespace\n");
}

void nd_region_create_btt_seed(struct nd_region *nd_region)
{
        WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
        nd_region->btt_seed = nd_btt_create(nd_region);
        /*
         * Seed creation failures are not fatal, provisioning is simply
         * disabled until memory becomes available
         */
        if (!nd_region->btt_seed)
                dev_err(&nd_region->dev, "failed to create btt namespace\n");
}

static int add_namespace_resource(struct nd_region *nd_region,
                struct nd_namespace_label *nd_label, struct device **devs,
                int count)
{
        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        int i;

        for (i = 0; i < count; i++) {
                u8 *uuid = namespace_to_uuid(devs[i]);
                struct resource *res;

                if (IS_ERR_OR_NULL(uuid)) {
                        WARN_ON(1);
                        continue;
                }

                if (memcmp(uuid, nd_label->uuid, NSLABEL_UUID_LEN) != 0)
                        continue;
                if (is_namespace_blk(devs[i])) {
                        res = nsblk_add_resource(nd_region, ndd,
                                        to_nd_namespace_blk(devs[i]),
                                        __le64_to_cpu(nd_label->dpa));
                        if (!res)
                                return -ENXIO;
                        nd_dbg_dpa(nd_region, ndd, res, "%d assign\n", count);
                } else {
                        dev_err(&nd_region->dev,
                                        "error: conflicting extents for uuid: %pUb\n",
                                        nd_label->uuid);
                        return -ENXIO;
                }
                break;
        }

        return i;
}

static struct device *create_namespace_blk(struct nd_region *nd_region,
                struct nd_namespace_label *nd_label, int count)
{

        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        struct nd_interleave_set *nd_set = nd_region->nd_set;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
        struct nd_namespace_blk *nsblk;
        char name[NSLABEL_NAME_LEN];
        struct device *dev = NULL;
        struct resource *res;

        if (namespace_label_has(ndd, type_guid)) {
                if (!guid_equal(&nd_set->type_guid, &nd_label->type_guid)) {
                        dev_dbg(ndd->dev, "expect type_guid %pUb got %pUb\n",
                                        nd_set->type_guid.b,
                                        nd_label->type_guid.b);
                        return ERR_PTR(-EAGAIN);
                }

                if (nd_label->isetcookie != __cpu_to_le64(nd_set->cookie2)) {
                        dev_dbg(ndd->dev, "expect cookie %#llx got %#llx\n",
                                        nd_set->cookie2,
                                        __le64_to_cpu(nd_label->isetcookie));
                        return ERR_PTR(-EAGAIN);
                }
        }

        nsblk = kzalloc(sizeof(*nsblk), GFP_KERNEL);
        if (!nsblk)
                return ERR_PTR(-ENOMEM);
        dev = &nsblk->common.dev;
        dev->type = &namespace_blk_device_type;
        dev->parent = &nd_region->dev;
        nsblk->id = -1;
        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);
        if (name[0])
                nsblk->alt_name = kmemdup(name, NSLABEL_NAME_LEN,
                                GFP_KERNEL);
        res = nsblk_add_resource(nd_region, ndd, nsblk,
                        __le64_to_cpu(nd_label->dpa));
        if (!res)
                goto blk_err;
        nd_dbg_dpa(nd_region, ndd, res, "%d: assign\n", count);
        return dev;
 blk_err:
        namespace_blk_release(dev);
        return ERR_PTR(-ENXIO);
}

static int cmp_dpa(const void *a, const void *b)
{
        const struct device *dev_a = *(const struct device **) a;
        const struct device *dev_b = *(const struct device **) b;
        struct nd_namespace_blk *nsblk_a, *nsblk_b;
        struct nd_namespace_pmem *nspm_a, *nspm_b;

        if (is_namespace_io(dev_a))
                return 0;

        if (is_namespace_blk(dev_a)) {
                nsblk_a = to_nd_namespace_blk(dev_a);
                nsblk_b = to_nd_namespace_blk(dev_b);

                return memcmp(&nsblk_a->res[0]->start, &nsblk_b->res[0]->start,
                                sizeof(resource_size_t));
        }

        nspm_a = to_nd_namespace_pmem(dev_a);
        nspm_b = to_nd_namespace_pmem(dev_b);

        return memcmp(&nspm_a->nsio.res.start, &nspm_b->nsio.res.start,
                        sizeof(resource_size_t));
}

static struct device **scan_labels(struct nd_region *nd_region)
{
        int i, count = 0;
        struct device *dev, **devs = NULL;
        struct nd_label_ent *label_ent, *e;
        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
        resource_size_t map_end = nd_mapping->start + nd_mapping->size - 1;

        /* "safe" because create_namespace_pmem() might list_move() label_ent */
        list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
                struct nd_namespace_label *nd_label = label_ent->label;
                struct device **__devs;
                u32 flags;

                if (!nd_label)
                        continue;
                flags = __le32_to_cpu(nd_label->flags);
                if (is_nd_blk(&nd_region->dev)
                                == !!(flags & NSLABEL_FLAG_LOCAL))
                        /* pass, region matches label type */;
                else
                        continue;

                /* skip labels that describe extents outside of the region */
                if (nd_label->dpa < nd_mapping->start || nd_label->dpa > map_end)
                        continue;

                i = add_namespace_resource(nd_region, nd_label, devs, count);
                if (i < 0)
                        goto err;
                if (i < count)
                        continue;
                __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL);
                if (!__devs)
                        goto err;
                memcpy(__devs, devs, sizeof(dev) * count);
                kfree(devs);
                devs = __devs;

                if (is_nd_blk(&nd_region->dev))
                        dev = create_namespace_blk(nd_region, nd_label, count);
                else {
                        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                        struct nd_namespace_index *nsindex;

                        nsindex = to_namespace_index(ndd, ndd->ns_current);
                        dev = create_namespace_pmem(nd_region, nsindex, nd_label);
                }

                if (IS_ERR(dev)) {
                        switch (PTR_ERR(dev)) {
                        case -EAGAIN:
                                /* skip invalid labels */
                                continue;
                        case -ENODEV:
                                /* fallthrough to seed creation */
                                break;
                        default:
                                goto err;
                        }
                } else
                        devs[count++] = dev;

        }

        dev_dbg(&nd_region->dev, "discovered %d %s namespace%s\n",
                        count, is_nd_blk(&nd_region->dev)
                        ? "blk" : "pmem", count == 1 ? "" : "s");

        if (count == 0) {
                /* Publish a zero-sized namespace for userspace to configure. */
                nd_mapping_free_labels(nd_mapping);

                devs = kcalloc(2, sizeof(dev), GFP_KERNEL);
                if (!devs)
                        goto err;
                if (is_nd_blk(&nd_region->dev)) {
                        struct nd_namespace_blk *nsblk;

                        nsblk = kzalloc(sizeof(*nsblk), GFP_KERNEL);
                        if (!nsblk)
                                goto err;
                        dev = &nsblk->common.dev;
                        dev->type = &namespace_blk_device_type;
                } else {
                        struct nd_namespace_pmem *nspm;

                        nspm = kzalloc(sizeof(*nspm), GFP_KERNEL);
                        if (!nspm)
                                goto err;
                        dev = &nspm->nsio.common.dev;
                        dev->type = &namespace_pmem_device_type;
                        nd_namespace_pmem_set_resource(nd_region, nspm, 0);
                }
                dev->parent = &nd_region->dev;
                devs[count++] = dev;
        } else if (is_memory(&nd_region->dev)) {
                /* clean unselected labels */
                for (i = 0; i < nd_region->ndr_mappings; i++) {
                        struct list_head *l, *e;
                        LIST_HEAD(list);
                        int j;

                        nd_mapping = &nd_region->mapping[i];
                        if (list_empty(&nd_mapping->labels)) {
                                WARN_ON(1);
                                continue;
                        }

                        j = count;
                        list_for_each_safe(l, e, &nd_mapping->labels) {
                                if (!j--)
                                        break;
                                list_move_tail(l, &list);
                        }
                        nd_mapping_free_labels(nd_mapping);
                        list_splice_init(&list, &nd_mapping->labels);
                }
        }

        if (count > 1)
                sort(devs, count, sizeof(struct device *), cmp_dpa, NULL);

        return devs;

 err:
        if (devs) {
                for (i = 0; devs[i]; i++)
                        if (is_nd_blk(&nd_region->dev))
                                namespace_blk_release(devs[i]);
                        else
                                namespace_pmem_release(devs[i]);
                kfree(devs);
        }
        return NULL;
}

static struct device **create_namespaces(struct nd_region *nd_region)
{
        struct nd_mapping *nd_mapping;
        struct device **devs;
        int i;

        if (nd_region->ndr_mappings == 0)
                return NULL;

        /* lock down all mappings while we scan labels */
        for (i = 0; i < nd_region->ndr_mappings; i++) {
                nd_mapping = &nd_region->mapping[i];
                mutex_lock_nested(&nd_mapping->lock, i);
        }

        devs = scan_labels(nd_region);

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                int reverse = nd_region->ndr_mappings - 1 - i;

                nd_mapping = &nd_region->mapping[reverse];
                mutex_unlock(&nd_mapping->lock);
        }

        return devs;
}

static int init_active_labels(struct nd_region *nd_region)
{
        int i;

        for (i = 0; i < nd_region->ndr_mappings; i++) {
                struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                struct nvdimm *nvdimm = nd_mapping->nvdimm;
                struct nd_label_ent *label_ent;
                int count, j;

                /*
                 * If the dimm is disabled then we may need to prevent
                 * the region from being activated.
                 */
                if (!ndd) {
                        if (test_bit(NDD_LOCKED, &nvdimm->flags))
                                /* fail, label data may be unreadable */;
                        else if (test_bit(NDD_ALIASING, &nvdimm->flags))
                                /* fail, labels needed to disambiguate dpa */;
                        else
                                return 0;

                        dev_err(&nd_region->dev, "%s: is %s, failing probe\n",
                                        dev_name(&nd_mapping->nvdimm->dev),
                                        test_bit(NDD_LOCKED, &nvdimm->flags)
                                        ? "locked" : "disabled");
                        return -ENXIO;
                }
                nd_mapping->ndd = ndd;
                atomic_inc(&nvdimm->busy);
                get_ndd(ndd);

                count = nd_label_active_count(ndd);
                dev_dbg(ndd->dev, "count: %d\n", count);
                if (!count)
                        continue;
                for (j = 0; j < count; j++) {
                        struct nd_namespace_label *label;

                        label_ent = kzalloc(sizeof(*label_ent), GFP_KERNEL);
                        if (!label_ent)
                                break;
                        label = nd_label_active(ndd, j);
                        label_ent->label = label;

                        mutex_lock(&nd_mapping->lock);
                        list_add_tail(&label_ent->list, &nd_mapping->labels);
                        mutex_unlock(&nd_mapping->lock);
                }

                if (j >= count)
                        continue;

                mutex_lock(&nd_mapping->lock);
                nd_mapping_free_labels(nd_mapping);
                mutex_unlock(&nd_mapping->lock);
                return -ENOMEM;
        }

        return 0;
}

int nd_region_register_namespaces(struct nd_region *nd_region, int *err)
{
        struct device **devs = NULL;
        int i, rc = 0, type;

        *err = 0;
        nvdimm_bus_lock(&nd_region->dev);
        rc = init_active_labels(nd_region);
        if (rc) {
                nvdimm_bus_unlock(&nd_region->dev);
                return rc;
        }

        type = nd_region_to_nstype(nd_region);
        switch (type) {
        case ND_DEVICE_NAMESPACE_IO:
                devs = create_namespace_io(nd_region);
                break;
        case ND_DEVICE_NAMESPACE_PMEM:
        case ND_DEVICE_NAMESPACE_BLK:
                devs = create_namespaces(nd_region);
                break;
        default:
                break;
        }
        nvdimm_bus_unlock(&nd_region->dev);

        if (!devs)
                return -ENODEV;

        for (i = 0; devs[i]; i++) {
                struct device *dev = devs[i];
                int id;

                if (type == ND_DEVICE_NAMESPACE_BLK) {
                        struct nd_namespace_blk *nsblk;

                        nsblk = to_nd_namespace_blk(dev);
                        id = ida_simple_get(&nd_region->ns_ida, 0, 0,
                                        GFP_KERNEL);
                        nsblk->id = id;
                } else if (type == ND_DEVICE_NAMESPACE_PMEM) {
                        struct nd_namespace_pmem *nspm;

                        nspm = to_nd_namespace_pmem(dev);
                        id = ida_simple_get(&nd_region->ns_ida, 0, 0,
                                        GFP_KERNEL);
                        nspm->id = id;
                } else
                        id = i;

                if (id < 0)
                        break;
                dev_set_name(dev, "namespace%d.%d", nd_region->id, id);
                dev->groups = nd_namespace_attribute_groups;
                nd_device_register(dev);
        }
        if (i)
                nd_region->ns_seed = devs[0];

        if (devs[i]) {
                int j;

                for (j = i; devs[j]; j++) {
                        struct device *dev = devs[j];

                        device_initialize(dev);
                        put_device(dev);
                }
                *err = j - i;
                /*
                 * All of the namespaces we tried to register failed, so
                 * fail region activation.
                 */
                if (*err == 0)
                        rc = -ENODEV;
        }
        kfree(devs);

        if (rc == -ENODEV)
                return rc;

        return i;
}