[mirror_ubuntu-zesty-kernel.git] / drivers / nvdimm / btt_devs.c

/*
 * 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/blkdev.h>
#include <linux/device.h>
#include <linux/genhd.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include "nd-core.h"
#include "btt.h"
#include "nd.h"

static void nd_btt_release(struct device *dev)
{
	struct nd_region *nd_region = to_nd_region(dev->parent);
	struct nd_btt *nd_btt = to_nd_btt(dev);

	dev_dbg(dev, "%s\n", __func__);
	nd_detach_ndns(&nd_btt->dev, &nd_btt->ndns);
	ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
	kfree(nd_btt->uuid);
	kfree(nd_btt);
}

static struct device_type nd_btt_device_type = {
	.name = "nd_btt",
	.release = nd_btt_release,
};

bool is_nd_btt(struct device *dev)
{
	return dev->type == &nd_btt_device_type;
}
EXPORT_SYMBOL(is_nd_btt);

struct nd_btt *to_nd_btt(struct device *dev)
{
	struct nd_btt *nd_btt = container_of(dev, struct nd_btt, dev);

	WARN_ON(!is_nd_btt(dev));
	return nd_btt;
}
EXPORT_SYMBOL(to_nd_btt);

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

static ssize_t sector_size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);

	return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
}

static ssize_t sector_size_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t len)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);
	ssize_t rc;

	device_lock(dev);
	nvdimm_bus_lock(dev);
	rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
			btt_lbasize_supported);
	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
			rc, 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 uuid_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);

	if (nd_btt->uuid)
		return sprintf(buf, "%pUb\n", nd_btt->uuid);
	return sprintf(buf, "\n");
}

static ssize_t uuid_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t len)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);
	ssize_t rc;

	device_lock(dev);
	rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);
	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
	device_unlock(dev);

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

static ssize_t namespace_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);
	ssize_t rc;

	nvdimm_bus_lock(dev);
	rc = sprintf(buf, "%s\n", nd_btt->ndns
			? dev_name(&nd_btt->ndns->dev) : "");
	nvdimm_bus_unlock(dev);
	return rc;
}

static ssize_t namespace_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t len)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);
	ssize_t rc;

	device_lock(dev);
	nvdimm_bus_lock(dev);
	rc = nd_namespace_store(dev, &nd_btt->ndns, buf, len);
	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
	nvdimm_bus_unlock(dev);
	device_unlock(dev);

	return rc;
}
static DEVICE_ATTR_RW(namespace);

static ssize_t size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nd_btt *nd_btt = to_nd_btt(dev);
	ssize_t rc;

	device_lock(dev);
	if (dev->driver)
		rc = sprintf(buf, "%llu\n", nd_btt->size);
	else {
		/* no size to convey if the btt instance is disabled */
		rc = -ENXIO;
	}
	device_unlock(dev);

	return rc;
}
static DEVICE_ATTR_RO(size);

static struct attribute *nd_btt_attributes[] = {
	&dev_attr_sector_size.attr,
	&dev_attr_namespace.attr,
	&dev_attr_uuid.attr,
	&dev_attr_size.attr,
	NULL,
};

static struct attribute_group nd_btt_attribute_group = {
	.attrs = nd_btt_attributes,
};

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

static struct device *__nd_btt_create(struct nd_region *nd_region,
		unsigned long lbasize, u8 *uuid,
		struct nd_namespace_common *ndns)
{
	struct nd_btt *nd_btt;
	struct device *dev;

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

	nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
	if (nd_btt->id < 0) {
		kfree(nd_btt);
		return NULL;
	}

	nd_btt->lbasize = lbasize;
	if (uuid)
		uuid = kmemdup(uuid, 16, GFP_KERNEL);
	nd_btt->uuid = uuid;
	dev = &nd_btt->dev;
	dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
	dev->parent = &nd_region->dev;
	dev->type = &nd_btt_device_type;
	dev->groups = nd_btt_attribute_groups;
	device_initialize(&nd_btt->dev);
	if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
		dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
				__func__, dev_name(ndns->claim));
		put_device(dev);
		return NULL;
	}
	return dev;
}

struct device *nd_btt_create(struct nd_region *nd_region)
{
	struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);

	__nd_device_register(dev);
	return dev;
}

static bool uuid_is_null(u8 *uuid)
{
	static const u8 null_uuid[16];

	return (memcmp(uuid, null_uuid, 16) == 0);
}

/**
 * nd_btt_arena_is_valid - check if the metadata layout is valid
 * @nd_btt:	device with BTT geometry and backing device info
 * @super:	pointer to the arena's info block being tested
 *
 * Check consistency of the btt info block with itself by validating
 * the checksum, and with the parent namespace by verifying the
 * parent_uuid contained in the info block with the one supplied in.
 *
 * Returns:
 * false for an invalid info block, true for a valid one
 */
bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
{
	const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
	u64 checksum;

	if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0)
		return false;

	if (!uuid_is_null(super->parent_uuid))
		if (memcmp(super->parent_uuid, parent_uuid, 16) != 0)
			return false;

	checksum = le64_to_cpu(super->checksum);
	super->checksum = 0;
	if (checksum != nd_sb_checksum((struct nd_gen_sb *) super))
		return false;
	super->checksum = cpu_to_le64(checksum);

	/* TODO: figure out action for this */
	if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)
		dev_info(&nd_btt->dev, "Found arena with an error flag\n");

	return true;
}
EXPORT_SYMBOL(nd_btt_arena_is_valid);

static int __nd_btt_probe(struct nd_btt *nd_btt,
		struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
{
	if (!btt_sb || !ndns || !nd_btt)
		return -ENODEV;

	if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb)))
		return -ENXIO;

	if (nvdimm_namespace_capacity(ndns) < SZ_16M)
		return -ENXIO;

	if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
		return -ENODEV;

	nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
	nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
	if (!nd_btt->uuid)
		return -ENOMEM;

	__nd_device_register(&nd_btt->dev);

	return 0;
}

int nd_btt_probe(struct device *dev, struct nd_namespace_common *ndns)
{
	int rc;
	struct device *btt_dev;
	struct btt_sb *btt_sb;
	struct nd_region *nd_region = to_nd_region(ndns->dev.parent);

	if (ndns->force_raw)
		return -ENODEV;

	nvdimm_bus_lock(&ndns->dev);
	btt_dev = __nd_btt_create(nd_region, 0, NULL, ndns);
	nvdimm_bus_unlock(&ndns->dev);
	if (!btt_dev)
		return -ENOMEM;
	btt_sb = devm_kzalloc(dev, sizeof(*btt_sb), GFP_KERNEL);
	rc = __nd_btt_probe(to_nd_btt(btt_dev), ndns, btt_sb);
	dev_dbg(dev, "%s: btt: %s\n", __func__,
			rc == 0 ? dev_name(btt_dev) : "<none>");
	if (rc < 0) {
		struct nd_btt *nd_btt = to_nd_btt(btt_dev);

		__nd_detach_ndns(btt_dev, &nd_btt->ndns);
		put_device(btt_dev);
	}

	return rc;
}
EXPORT_SYMBOL(nd_btt_probe);
Commit	Line	Data
8c2f7e86 DW	1	/*
	2	* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of version 2 of the GNU General Public License as
	6	* published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful, but
	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*/
	13	#include <linux/blkdev.h>
	14	#include <linux/device.h>
	15	#include <linux/genhd.h>
	16	#include <linux/sizes.h>
	17	#include <linux/slab.h>
	18	#include <linux/fs.h>
	19	#include <linux/mm.h>
	20	#include "nd-core.h"
	21	#include "btt.h"
	22	#include "nd.h"
	23
8c2f7e86 DW	24	static void nd_btt_release(struct device *dev)
	25	{
	26	struct nd_region *nd_region = to_nd_region(dev->parent);
	27	struct nd_btt *nd_btt = to_nd_btt(dev);
	28
	29	dev_dbg(dev, "%s\n", __func__);
e1455744	30	nd_detach_ndns(&nd_btt->dev, &nd_btt->ndns);
8c2f7e86 DW	31	ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
	32	kfree(nd_btt->uuid);
	33	kfree(nd_btt);
	34	}
	35
	36	static struct device_type nd_btt_device_type = {
	37	.name = "nd_btt",
	38	.release = nd_btt_release,
	39	};
	40
	41	bool is_nd_btt(struct device *dev)
	42	{
	43	return dev->type == &nd_btt_device_type;
	44	}
	45	EXPORT_SYMBOL(is_nd_btt);
	46
	47	struct nd_btt to_nd_btt(struct device dev)
	48	{
	49	struct nd_btt *nd_btt = container_of(dev, struct nd_btt, dev);
	50
	51	WARN_ON(!is_nd_btt(dev));
	52	return nd_btt;
	53	}
	54	EXPORT_SYMBOL(to_nd_btt);
	55
41cd8b70 VV	56	static const unsigned long btt_lbasize_supported[] = { 512, 520, 528,
41cd8b70 VV	57	4096, 4104, 4160, 4224, 0 };
8c2f7e86 DW	58
	59	static ssize_t sector_size_show(struct device *dev,
	60	struct device_attribute attr, char buf)
	61	{
	62	struct nd_btt *nd_btt = to_nd_btt(dev);
	63
	64	return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
	65	}
	66
	67	static ssize_t sector_size_store(struct device *dev,
	68	struct device_attribute attr, const char buf, size_t len)
	69	{
	70	struct nd_btt *nd_btt = to_nd_btt(dev);
	71	ssize_t rc;
	72
	73	device_lock(dev);
	74	nvdimm_bus_lock(dev);
	75	rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
	76	btt_lbasize_supported);
	77	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
	78	rc, buf, buf[len - 1] == '\n' ? "" : "\n");
	79	nvdimm_bus_unlock(dev);
	80	device_unlock(dev);
	81
	82	return rc ? rc : len;
	83	}
	84	static DEVICE_ATTR_RW(sector_size);
	85
	86	static ssize_t uuid_show(struct device *dev,
	87	struct device_attribute attr, char buf)
	88	{
	89	struct nd_btt *nd_btt = to_nd_btt(dev);
	90
	91	if (nd_btt->uuid)
	92	return sprintf(buf, "%pUb\n", nd_btt->uuid);
	93	return sprintf(buf, "\n");
	94	}
	95
	96	static ssize_t uuid_store(struct device *dev,
	97	struct device_attribute attr, const char buf, size_t len)
	98	{
	99	struct nd_btt *nd_btt = to_nd_btt(dev);
	100	ssize_t rc;
	101
	102	device_lock(dev);
	103	rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);
	104	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
	105	rc, buf, buf[len - 1] == '\n' ? "" : "\n");
	106	device_unlock(dev);
	107
	108	return rc ? rc : len;
	109	}
	110	static DEVICE_ATTR_RW(uuid);
	111
	112	static ssize_t namespace_show(struct device *dev,
	113	struct device_attribute attr, char buf)
	114	{
	115	struct nd_btt *nd_btt = to_nd_btt(dev);
	116	ssize_t rc;
	117
	118	nvdimm_bus_lock(dev);
	119	rc = sprintf(buf, "%s\n", nd_btt->ndns
	120	? dev_name(&nd_btt->ndns->dev) : "");
	121	nvdimm_bus_unlock(dev);
122	return rc;
123	}
124
8c2f7e86 DW	125	static ssize_t namespace_store(struct device *dev,
	126	struct device_attribute attr, const char buf, size_t len)
	127	{
e1455744	128	struct nd_btt *nd_btt = to_nd_btt(dev);
8c2f7e86 DW	129	ssize_t rc;
8c2f7e86 DW	130
8c2f7e86	131	device_lock(dev);
4be9c1fc	132	nvdimm_bus_lock(dev);
e1455744	133	rc = nd_namespace_store(dev, &nd_btt->ndns, buf, len);
8c2f7e86 DW	134	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
8c2f7e86 DW	135	rc, buf, buf[len - 1] == '\n' ? "" : "\n");
8c2f7e86	136	nvdimm_bus_unlock(dev);
4be9c1fc	137	device_unlock(dev);
8c2f7e86 DW	138
	139	return rc;
	140	}
	141	static DEVICE_ATTR_RW(namespace);
	142
abe8b4e3 VV	143	static ssize_t size_show(struct device *dev,
	144	struct device_attribute attr, char buf)
	145	{
	146	struct nd_btt *nd_btt = to_nd_btt(dev);
	147	ssize_t rc;
	148
	149	device_lock(dev);
	150	if (dev->driver)
	151	rc = sprintf(buf, "%llu\n", nd_btt->size);
	152	else {
	153	/* no size to convey if the btt instance is disabled */
	154	rc = -ENXIO;
	155	}
	156	device_unlock(dev);
	157
	158	return rc;
	159	}
	160	static DEVICE_ATTR_RO(size);
	161
8c2f7e86 DW	162	static struct attribute *nd_btt_attributes[] = {
	163	&dev_attr_sector_size.attr,
	164	&dev_attr_namespace.attr,
	165	&dev_attr_uuid.attr,
abe8b4e3	166	&dev_attr_size.attr,
8c2f7e86 DW	167	NULL,
	168	};
	169
	170	static struct attribute_group nd_btt_attribute_group = {
	171	.attrs = nd_btt_attributes,
	172	};
	173
	174	static const struct attribute_group *nd_btt_attribute_groups[] = {
	175	&nd_btt_attribute_group,
	176	&nd_device_attribute_group,
74ae66c3	177	&nd_numa_attribute_group,
8c2f7e86 DW	178	NULL,
	179	};
	180
	181	static struct device __nd_btt_create(struct nd_region nd_region,
	182	unsigned long lbasize, u8 *uuid,
	183	struct nd_namespace_common *ndns)
	184	{
	185	struct nd_btt *nd_btt;
	186	struct device *dev;
	187
	188	nd_btt = kzalloc(sizeof(*nd_btt), GFP_KERNEL);
	189	if (!nd_btt)
	190	return NULL;
	191
	192	nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
	193	if (nd_btt->id < 0) {
	194	kfree(nd_btt);
	195	return NULL;
	196	}
	197
	198	nd_btt->lbasize = lbasize;
	199	if (uuid)
	200	uuid = kmemdup(uuid, 16, GFP_KERNEL);
	201	nd_btt->uuid = uuid;
	202	dev = &nd_btt->dev;
	203	dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
	204	dev->parent = &nd_region->dev;
	205	dev->type = &nd_btt_device_type;
	206	dev->groups = nd_btt_attribute_groups;
	207	device_initialize(&nd_btt->dev);
e1455744	208	if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
8c2f7e86 DW	209	dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
	210	__func__, dev_name(ndns->claim));
	211	put_device(dev);
	212	return NULL;
	213	}
	214	return dev;
	215	}
	216
	217	struct device nd_btt_create(struct nd_region nd_region)
	218	{
	219	struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);
	220
d4c5725d	221	__nd_device_register(dev);
8c2f7e86 DW	222	return dev;
	223	}
	224
6ec68954 VV	225	static bool uuid_is_null(u8 *uuid)
	226	{
	227	static const u8 null_uuid[16];
	228
	229	return (memcmp(uuid, null_uuid, 16) == 0);
	230	}
	231
ab45e763 VV	232	/**
	233	* nd_btt_arena_is_valid - check if the metadata layout is valid
	234	* @nd_btt: device with BTT geometry and backing device info
	235	* @super: pointer to the arena's info block being tested
	236	*
	237	* Check consistency of the btt info block with itself by validating
6ec68954 VV	238	* the checksum, and with the parent namespace by verifying the
6ec68954 VV	239	* parent_uuid contained in the info block with the one supplied in.
ab45e763 VV	240	*
	241	* Returns:
	242	* false for an invalid info block, true for a valid one
	243	*/
	244	bool nd_btt_arena_is_valid(struct nd_btt nd_btt, struct btt_sb super)
	245	{
6ec68954	246	const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
ab45e763 VV	247	u64 checksum;
	248
	249	if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0)
	250	return false;
	251
6ec68954 VV	252	if (!uuid_is_null(super->parent_uuid))
	253	if (memcmp(super->parent_uuid, parent_uuid, 16) != 0)
	254	return false;
	255
ab45e763 VV	256	checksum = le64_to_cpu(super->checksum);
ab45e763 VV	257	super->checksum = 0;
e1455744	258	if (checksum != nd_sb_checksum((struct nd_gen_sb *) super))
ab45e763 VV	259	return false;
	260	super->checksum = cpu_to_le64(checksum);
	261
	262	/* TODO: figure out action for this */
	263	if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)
	264	dev_info(&nd_btt->dev, "Found arena with an error flag\n");
	265
	266	return true;
	267	}
	268	EXPORT_SYMBOL(nd_btt_arena_is_valid);
	269
8c2f7e86 DW	270	static int __nd_btt_probe(struct nd_btt *nd_btt,
	271	struct nd_namespace_common ndns, struct btt_sb btt_sb)
	272	{
8c2f7e86 DW	273	if (!btt_sb \|\| !ndns \|\| !nd_btt)
	274	return -ENODEV;
	275
	276	if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb)))
	277	return -ENXIO;
	278
	279	if (nvdimm_namespace_capacity(ndns) < SZ_16M)
	280	return -ENXIO;
	281
ab45e763	282	if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
8c2f7e86	283	return -ENODEV;
8c2f7e86 DW	284
	285	nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
	286	nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
	287	if (!nd_btt->uuid)
	288	return -ENOMEM;
	289
	290	__nd_device_register(&nd_btt->dev);
	291
	292	return 0;
	293	}
	294
200c79da	295	int nd_btt_probe(struct device dev, struct nd_namespace_common ndns)
8c2f7e86 DW	296	{
8c2f7e86 DW	297	int rc;
e32bc729	298	struct device *btt_dev;
8c2f7e86 DW	299	struct btt_sb *btt_sb;
	300	struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
	301
	302	if (ndns->force_raw)
	303	return -ENODEV;
	304
	305	nvdimm_bus_lock(&ndns->dev);
e32bc729	306	btt_dev = __nd_btt_create(nd_region, 0, NULL, ndns);
8c2f7e86	307	nvdimm_bus_unlock(&ndns->dev);
e32bc729	308	if (!btt_dev)
8c2f7e86	309	return -ENOMEM;
e32bc729 DW	310	btt_sb = devm_kzalloc(dev, sizeof(*btt_sb), GFP_KERNEL);
	311	rc = __nd_btt_probe(to_nd_btt(btt_dev), ndns, btt_sb);
	312	dev_dbg(dev, "%s: btt: %s\n", __func__,
	313	rc == 0 ? dev_name(btt_dev) : "<none>");
8c2f7e86	314	if (rc < 0) {
e32bc729	315	struct nd_btt *nd_btt = to_nd_btt(btt_dev);
e1455744	316
e32bc729 DW	317	__nd_detach_ndns(btt_dev, &nd_btt->ndns);
e32bc729 DW	318	put_device(btt_dev);
8c2f7e86 DW	319	}
	320
	321	return rc;
	322	}
	323	EXPORT_SYMBOL(nd_btt_probe);