Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 717 insertions, 0 deletions

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
new file mode 100644
index 000000000..f0e0e3b42
--- /dev/null
+++ b/drivers/nvdimm/dimm_devs.c
@@ -0,0 +1,717 @@
+/*
+ * 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.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/vmalloc.h>
+#include <linux/device.h>
+#include <linux/ndctl.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include "nd-core.h"
+#include "label.h"
+#include "pmem.h"
+#include "nd.h"
+
+static DEFINE_IDA(dimm_ida);
+
+/*
+ * Retrieve bus and dimm handle and return if this bus supports
+ * get_config_data commands
+ */
+int nvdimm_check_config_data(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	if (!nvdimm->cmd_mask ||
+	    !test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask)) {
+		if (test_bit(NDD_ALIASING, &nvdimm->flags))
+			return -ENXIO;
+		else
+			return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static int validate_dimm(struct nvdimm_drvdata *ndd)
+{
+	int rc;
+
+	if (!ndd)
+		return -EINVAL;
+
+	rc = nvdimm_check_config_data(ndd->dev);
+	if (rc)
+		dev_dbg(ndd->dev, "%pf: %s error: %d\n",
+				__builtin_return_address(0), __func__, rc);
+	return rc;
+}
+
+/**
+ * nvdimm_init_nsarea - determine the geometry of a dimm's namespace area
+ * @nvdimm: dimm to initialize
+ */
+int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd)
+{
+	struct nd_cmd_get_config_size *cmd = &ndd->nsarea;
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus_descriptor *nd_desc;
+	int rc = validate_dimm(ndd);
+	int cmd_rc = 0;
+
+	if (rc)
+		return rc;
+
+	if (cmd->config_size)
+		return 0; /* already valid */
+
+	memset(cmd, 0, sizeof(*cmd));
+	nd_desc = nvdimm_bus->nd_desc;
+	rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
+			ND_CMD_GET_CONFIG_SIZE, cmd, sizeof(*cmd), &cmd_rc);
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
+}
+
+int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
+{
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	int rc = validate_dimm(ndd), cmd_rc = 0;
+	struct nd_cmd_get_config_data_hdr *cmd;
+	struct nvdimm_bus_descriptor *nd_desc;
+	u32 max_cmd_size, config_size;
+	size_t offset;
+
+	if (rc)
+		return rc;
+
+	if (ndd->data)
+		return 0;
+
+	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0
+			|| ndd->nsarea.config_size < ND_LABEL_MIN_SIZE) {
+		dev_dbg(ndd->dev, "failed to init config data area: (%d:%d)\n",
+				ndd->nsarea.max_xfer, ndd->nsarea.config_size);
+		return -ENXIO;
+	}
+
+	ndd->data = kvmalloc(ndd->nsarea.config_size, GFP_KERNEL);
+	if (!ndd->data)
+		return -ENOMEM;
+
+	max_cmd_size = min_t(u32, PAGE_SIZE, ndd->nsarea.max_xfer);
+	cmd = kzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	nd_desc = nvdimm_bus->nd_desc;
+	for (config_size = ndd->nsarea.config_size, offset = 0;
+			config_size; config_size -= cmd->in_length,
+			offset += cmd->in_length) {
+		cmd->in_length = min(config_size, max_cmd_size);
+		cmd->in_offset = offset;
+		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
+				ND_CMD_GET_CONFIG_DATA, cmd,
+				cmd->in_length + sizeof(*cmd), &cmd_rc);
+		if (rc < 0)
+			break;
+		if (cmd_rc < 0) {
+			rc = cmd_rc;
+			break;
+		}
+		memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
+	}
+	dev_dbg(ndd->dev, "len: %zu rc: %d\n", offset, rc);
+	kfree(cmd);
+
+	return rc;
+}
+
+int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
+		void *buf, size_t len)
+{
+	size_t max_cmd_size, buf_offset;
+	struct nd_cmd_set_config_hdr *cmd;
+	int rc = validate_dimm(ndd), cmd_rc = 0;
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
+
+	if (rc)
+		return rc;
+
+	if (!ndd->data)
+		return -ENXIO;
+
+	if (offset + len > ndd->nsarea.config_size)
+		return -ENXIO;
+
+	max_cmd_size = min_t(u32, PAGE_SIZE, len);
+	max_cmd_size = min_t(u32, max_cmd_size, ndd->nsarea.max_xfer);
+	cmd = kzalloc(max_cmd_size + sizeof(*cmd) + sizeof(u32), GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	for (buf_offset = 0; len; len -= cmd->in_length,
+			buf_offset += cmd->in_length) {
+		size_t cmd_size;
+
+		cmd->in_offset = offset + buf_offset;
+		cmd->in_length = min(max_cmd_size, len);
+		memcpy(cmd->in_buf, buf + buf_offset, cmd->in_length);
+
+		/* status is output in the last 4-bytes of the command buffer */
+		cmd_size = sizeof(*cmd) + cmd->in_length + sizeof(u32);
+
+		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
+				ND_CMD_SET_CONFIG_DATA, cmd, cmd_size, &cmd_rc);
+		if (rc < 0)
+			break;
+		if (cmd_rc < 0) {
+			rc = cmd_rc;
+			break;
+		}
+	}
+	kfree(cmd);
+
+	return rc;
+}
+
+void nvdimm_set_aliasing(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	set_bit(NDD_ALIASING, &nvdimm->flags);
+}
+
+void nvdimm_set_locked(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	set_bit(NDD_LOCKED, &nvdimm->flags);
+}
+
+void nvdimm_clear_locked(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	clear_bit(NDD_LOCKED, &nvdimm->flags);
+}
+
+static void nvdimm_release(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	ida_simple_remove(&dimm_ida, nvdimm->id);
+	kfree(nvdimm);
+}
+
+static struct device_type nvdimm_device_type = {
+	.name = "nvdimm",
+	.release = nvdimm_release,
+};
+
+bool is_nvdimm(struct device *dev)
+{
+	return dev->type == &nvdimm_device_type;
+}
+
+struct nvdimm *to_nvdimm(struct device *dev)
+{
+	struct nvdimm *nvdimm = container_of(dev, struct nvdimm, dev);
+
+	WARN_ON(!is_nvdimm(dev));
+	return nvdimm;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm);
+
+struct nvdimm *nd_blk_region_to_dimm(struct nd_blk_region *ndbr)
+{
+	struct nd_region *nd_region = &ndbr->nd_region;
+	struct nd_mapping *nd_mapping = &nd_region->mapping[0];
+
+	return nd_mapping->nvdimm;
+}
+EXPORT_SYMBOL_GPL(nd_blk_region_to_dimm);
+
+unsigned long nd_blk_memremap_flags(struct nd_blk_region *ndbr)
+{
+	/* pmem mapping properties are private to libnvdimm */
+	return ARCH_MEMREMAP_PMEM;
+}
+EXPORT_SYMBOL_GPL(nd_blk_memremap_flags);
+
+struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping)
+{
+	struct nvdimm *nvdimm = nd_mapping->nvdimm;
+
+	WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm->dev));
+
+	return dev_get_drvdata(&nvdimm->dev);
+}
+EXPORT_SYMBOL(to_ndd);
+
+void nvdimm_drvdata_release(struct kref *kref)
+{
+	struct nvdimm_drvdata *ndd = container_of(kref, typeof(*ndd), kref);
+	struct device *dev = ndd->dev;
+	struct resource *res, *_r;
+
+	dev_dbg(dev, "trace\n");
+	nvdimm_bus_lock(dev);
+	for_each_dpa_resource_safe(ndd, res, _r)
+		nvdimm_free_dpa(ndd, res);
+	nvdimm_bus_unlock(dev);
+
+	kvfree(ndd->data);
+	kfree(ndd);
+	put_device(dev);
+}
+
+void get_ndd(struct nvdimm_drvdata *ndd)
+{
+	kref_get(&ndd->kref);
+}
+
+void put_ndd(struct nvdimm_drvdata *ndd)
+{
+	if (ndd)
+		kref_put(&ndd->kref, nvdimm_drvdata_release);
+}
+
+const char *nvdimm_name(struct nvdimm *nvdimm)
+{
+	return dev_name(&nvdimm->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_name);
+
+struct kobject *nvdimm_kobj(struct nvdimm *nvdimm)
+{
+	return &nvdimm->dev.kobj;
+}
+EXPORT_SYMBOL_GPL(nvdimm_kobj);
+
+unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm)
+{
+	return nvdimm->cmd_mask;
+}
+EXPORT_SYMBOL_GPL(nvdimm_cmd_mask);
+
+void *nvdimm_provider_data(struct nvdimm *nvdimm)
+{
+	if (nvdimm)
+		return nvdimm->provider_data;
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(nvdimm_provider_data);
+
+static ssize_t commands_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	int cmd, len = 0;
+
+	if (!nvdimm->cmd_mask)
+		return sprintf(buf, "\n");
+
+	for_each_set_bit(cmd, &nvdimm->cmd_mask, BITS_PER_LONG)
+		len += sprintf(buf + len, "%s ", nvdimm_cmd_name(cmd));
+	len += sprintf(buf + len, "\n");
+	return len;
+}
+static DEVICE_ATTR_RO(commands);
+
+static ssize_t flags_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	return sprintf(buf, "%s%s\n",
+			test_bit(NDD_ALIASING, &nvdimm->flags) ? "alias " : "",
+			test_bit(NDD_LOCKED, &nvdimm->flags) ? "lock " : "");
+}
+static DEVICE_ATTR_RO(flags);
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	/*
+	 * The state may be in the process of changing, userspace should
+	 * quiesce probing if it wants a static answer
+	 */
+	nvdimm_bus_lock(dev);
+	nvdimm_bus_unlock(dev);
+	return sprintf(buf, "%s\n", atomic_read(&nvdimm->busy)
+			? "active" : "idle");
+}
+static DEVICE_ATTR_RO(state);
+
+static ssize_t __available_slots_show(struct nvdimm_drvdata *ndd, char *buf)
+{
+	struct device *dev;
+	ssize_t rc;
+	u32 nfree;
+
+	if (!ndd)
+		return -ENXIO;
+
+	dev = ndd->dev;
+	nvdimm_bus_lock(dev);
+	nfree = nd_label_nfree(ndd);
+	if (nfree - 1 > nfree) {
+		dev_WARN_ONCE(dev, 1, "we ate our last label?\n");
+		nfree = 0;
+	} else
+		nfree--;
+	rc = sprintf(buf, "%d\n", nfree);
+	nvdimm_bus_unlock(dev);
+	return rc;
+}
+
+static ssize_t available_slots_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	ssize_t rc;
+
+	device_lock(dev);
+	rc = __available_slots_show(dev_get_drvdata(dev), buf);
+	device_unlock(dev);
+
+	return rc;
+}
+static DEVICE_ATTR_RO(available_slots);
+
+static struct attribute *nvdimm_attributes[] = {
+	&dev_attr_state.attr,
+	&dev_attr_flags.attr,
+	&dev_attr_commands.attr,
+	&dev_attr_available_slots.attr,
+	NULL,
+};
+
+struct attribute_group nvdimm_attribute_group = {
+	.attrs = nvdimm_attributes,
+};
+EXPORT_SYMBOL_GPL(nvdimm_attribute_group);
+
+struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
+		const struct attribute_group **groups, unsigned long flags,
+		unsigned long cmd_mask, int num_flush,
+		struct resource *flush_wpq)
+{
+	struct nvdimm *nvdimm = kzalloc(sizeof(*nvdimm), GFP_KERNEL);
+	struct device *dev;
+
+	if (!nvdimm)
+		return NULL;
+
+	nvdimm->id = ida_simple_get(&dimm_ida, 0, 0, GFP_KERNEL);
+	if (nvdimm->id < 0) {
+		kfree(nvdimm);
+		return NULL;
+	}
+	nvdimm->provider_data = provider_data;
+	nvdimm->flags = flags;
+	nvdimm->cmd_mask = cmd_mask;
+	nvdimm->num_flush = num_flush;
+	nvdimm->flush_wpq = flush_wpq;
+	atomic_set(&nvdimm->busy, 0);
+	dev = &nvdimm->dev;
+	dev_set_name(dev, "nmem%d", nvdimm->id);
+	dev->parent = &nvdimm_bus->dev;
+	dev->type = &nvdimm_device_type;
+	dev->devt = MKDEV(nvdimm_major, nvdimm->id);
+	dev->groups = groups;
+	nd_device_register(dev);
+
+	return nvdimm;
+}
+EXPORT_SYMBOL_GPL(nvdimm_create);
+
+int alias_dpa_busy(struct device *dev, void *data)
+{
+	resource_size_t map_end, blk_start, new;
+	struct blk_alloc_info *info = data;
+	struct nd_mapping *nd_mapping;
+	struct nd_region *nd_region;
+	struct nvdimm_drvdata *ndd;
+	struct resource *res;
+	int i;
+
+	if (!is_memory(dev))
+		return 0;
+
+	nd_region = to_nd_region(dev);
+	for (i = 0; i < nd_region->ndr_mappings; i++) {
+		nd_mapping  = &nd_region->mapping[i];
+		if (nd_mapping->nvdimm == info->nd_mapping->nvdimm)
+			break;
+	}
+
+	if (i >= nd_region->ndr_mappings)
+		return 0;
+
+	ndd = to_ndd(nd_mapping);
+	map_end = nd_mapping->start + nd_mapping->size - 1;
+	blk_start = nd_mapping->start;
+
+	/*
+	 * In the allocation case ->res is set to free space that we are
+	 * looking to validate against PMEM aliasing collision rules
+	 * (i.e. BLK is allocated after all aliased PMEM).
+	 */
+	if (info->res) {
+		if (info->res->start >= nd_mapping->start
+				&& info->res->start < map_end)
+			/* pass */;
+		else
+			return 0;
+	}
+
+ retry:
+	/*
+	 * Find the free dpa from the end of the last pmem allocation to
+	 * the end of the interleave-set mapping.
+	 */
+	for_each_dpa_resource(ndd, res) {
+		if (strncmp(res->name, "pmem", 4) != 0)
+			continue;
+		if ((res->start >= blk_start && res->start < map_end)
+				|| (res->end >= blk_start
+					&& res->end <= map_end)) {
+			new = max(blk_start, min(map_end + 1, res->end + 1));
+			if (new != blk_start) {
+				blk_start = new;
+				goto retry;
+			}
+		}
+	}
+
+	/* update the free space range with the probed blk_start */
+	if (info->res && blk_start > info->res->start) {
+		info->res->start = max(info->res->start, blk_start);
+		if (info->res->start > info->res->end)
+			info->res->end = info->res->start - 1;
+		return 1;
+	}
+
+	info->available -= blk_start - nd_mapping->start;
+
+	return 0;
+}
+
+/**
+ * nd_blk_available_dpa - account the unused dpa of BLK region
+ * @nd_mapping: container of dpa-resource-root + labels
+ *
+ * Unlike PMEM, BLK namespaces can occupy discontiguous DPA ranges, but
+ * we arrange for them to never start at an lower dpa than the last
+ * PMEM allocation in an aliased region.
+ */
+resource_size_t nd_blk_available_dpa(struct nd_region *nd_region)
+{
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
+	struct nd_mapping *nd_mapping = &nd_region->mapping[0];
+	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
+	struct blk_alloc_info info = {
+		.nd_mapping = nd_mapping,
+		.available = nd_mapping->size,
+		.res = NULL,
+	};
+	struct resource *res;
+
+	if (!ndd)
+		return 0;
+
+	device_for_each_child(&nvdimm_bus->dev, &info, alias_dpa_busy);
+
+	/* now account for busy blk allocations in unaliased dpa */
+	for_each_dpa_resource(ndd, res) {
+		if (strncmp(res->name, "blk", 3) != 0)
+			continue;
+		info.available -= resource_size(res);
+	}
+
+	return info.available;
+}
+
+/**
+ * nd_pmem_max_contiguous_dpa - For the given dimm+region, return the max
+ *			   contiguous unallocated dpa range.
+ * @nd_region: constrain available space check to this reference region
+ * @nd_mapping: container of dpa-resource-root + labels
+ */
+resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
+					   struct nd_mapping *nd_mapping)
+{
+	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
+	struct nvdimm_bus *nvdimm_bus;
+	resource_size_t max = 0;
+	struct resource *res;
+
+	/* if a dimm is disabled the available capacity is zero */
+	if (!ndd)
+		return 0;
+
+	nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	if (__reserve_free_pmem(&nd_region->dev, nd_mapping->nvdimm))
+		return 0;
+	for_each_dpa_resource(ndd, res) {
+		if (strcmp(res->name, "pmem-reserve") != 0)
+			continue;
+		if (resource_size(res) > max)
+			max = resource_size(res);
+	}
+	release_free_pmem(nvdimm_bus, nd_mapping);
+	return max;
+}
+
+/**
+ * nd_pmem_available_dpa - for the given dimm+region account unallocated dpa
+ * @nd_mapping: container of dpa-resource-root + labels
+ * @nd_region: constrain available space check to this reference region
+ * @overlap: calculate available space assuming this level of overlap
+ *
+ * Validate that a PMEM label, if present, aligns with the start of an
+ * interleave set and truncate the available size at the lowest BLK
+ * overlap point.
+ *
+ * The expectation is that this routine is called multiple times as it
+ * probes for the largest BLK encroachment for any single member DIMM of
+ * the interleave set.  Once that value is determined the PMEM-limit for
+ * the set can be established.
+ */
+resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
+		struct nd_mapping *nd_mapping, resource_size_t *overlap)
+{
+	resource_size_t map_start, map_end, busy = 0, available, blk_start;
+	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
+	struct resource *res;
+	const char *reason;
+
+	if (!ndd)
+		return 0;
+
+	map_start = nd_mapping->start;
+	map_end = map_start + nd_mapping->size - 1;
+	blk_start = max(map_start, map_end + 1 - *overlap);
+	for_each_dpa_resource(ndd, res) {
+		if (res->start >= map_start && res->start < map_end) {
+			if (strncmp(res->name, "blk", 3) == 0)
+				blk_start = min(blk_start,
+						max(map_start, res->start));
+			else if (res->end > map_end) {
+				reason = "misaligned to iset";
+				goto err;
+			} else
+				busy += resource_size(res);
+		} else if (res->end >= map_start && res->end <= map_end) {
+			if (strncmp(res->name, "blk", 3) == 0) {
+				/*
+				 * If a BLK allocation overlaps the start of
+				 * PMEM the entire interleave set may now only
+				 * be used for BLK.
+				 */
+				blk_start = map_start;
+			} else
+				busy += resource_size(res);
+		} else if (map_start > res->start && map_start < res->end) {
+			/* total eclipse of the mapping */
+			busy += nd_mapping->size;
+			blk_start = map_start;
+		}
+	}
+
+	*overlap = map_end + 1 - blk_start;
+	available = blk_start - map_start;
+	if (busy < available)
+		return available - busy;
+	return 0;
+
+ err:
+	nd_dbg_dpa(nd_region, ndd, res, "%s\n", reason);
+	return 0;
+}
+
+void nvdimm_free_dpa(struct nvdimm_drvdata *ndd, struct resource *res)
+{
+	WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));
+	kfree(res->name);
+	__release_region(&ndd->dpa, res->start, resource_size(res));
+}
+
+struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd,
+		struct nd_label_id *label_id, resource_size_t start,
+		resource_size_t n)
+{
+	char *name = kmemdup(label_id, sizeof(*label_id), GFP_KERNEL);
+	struct resource *res;
+
+	if (!name)
+		return NULL;
+
+	WARN_ON_ONCE(!is_nvdimm_bus_locked(ndd->dev));
+	res = __request_region(&ndd->dpa, start, n, name, 0);
+	if (!res)
+		kfree(name);
+	return res;
+}
+
+/**
+ * nvdimm_allocated_dpa - sum up the dpa currently allocated to this label_id
+ * @nvdimm: container of dpa-resource-root + labels
+ * @label_id: dpa resource name of the form {pmem|blk}-<human readable uuid>
+ */
+resource_size_t nvdimm_allocated_dpa(struct nvdimm_drvdata *ndd,
+		struct nd_label_id *label_id)
+{
+	resource_size_t allocated = 0;
+	struct resource *res;
+
+	for_each_dpa_resource(ndd, res)
+		if (strcmp(res->name, label_id->id) == 0)
+			allocated += resource_size(res);
+
+	return allocated;
+}
+
+static int count_dimms(struct device *dev, void *c)
+{
+	int *count = c;
+
+	if (is_nvdimm(dev))
+		(*count)++;
+	return 0;
+}
+
+int nvdimm_bus_check_dimm_count(struct nvdimm_bus *nvdimm_bus, int dimm_count)
+{
+	int count = 0;
+	/* Flush any possible dimm registration failures */
+	nd_synchronize();
+
+	device_for_each_child(&nvdimm_bus->dev, &count, count_dimms);
+	dev_dbg(&nvdimm_bus->dev, "count: %d\n", count);
+	if (count != dimm_count)
+		return -ENXIO;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_check_dimm_count);
+
+void __exit nvdimm_devs_exit(void)
+{
+	ida_destroy(&dimm_ida);
+}