[deliverable/linux.git] / drivers / md / dm-stripe.c

/*
 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
 *
 * This file is released under the GPL.
 */

#include <linux/device-mapper.h>

#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/log2.h>

#define DM_MSG_PREFIX "striped"
#define DM_IO_ERROR_THRESHOLD 15

struct stripe {
	struct dm_dev *dev;
	sector_t physical_start;

	atomic_t error_count;
};

struct stripe_c {
	uint32_t stripes;

	/* The size of this target / num. stripes */
	sector_t stripe_width;

	/* stripe chunk size */
	uint32_t chunk_shift;
	sector_t chunk_mask;

	/* Needed for handling events */
	struct dm_target *ti;

	/* Work struct used for triggering events*/
	struct work_struct kstriped_ws;

	struct stripe stripe[0];
};

static struct workqueue_struct *kstriped;

/*
 * An event is triggered whenever a drive
 * drops out of a stripe volume.
 */
static void trigger_event(struct work_struct *work)
{
	struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws);

	dm_table_event(sc->ti->table);

}

static inline struct stripe_c *alloc_context(unsigned int stripes)
{
	size_t len;

	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
			     stripes))
		return NULL;

	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);

	return kmalloc(len, GFP_KERNEL);
}

/*
 * Parse a single <dev> <sector> pair
 */
static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
		      unsigned int stripe, char **argv)
{
	unsigned long long start;

	if (sscanf(argv[1], "%llu", &start) != 1)
		return -EINVAL;

	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
			  &sc->stripe[stripe].dev))
		return -ENXIO;

	sc->stripe[stripe].physical_start = start;

	return 0;
}

/*
 * Construct a striped mapping.
 * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
 */
static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct stripe_c *sc;
	sector_t width;
	uint32_t stripes;
	uint32_t chunk_size;
	char *end;
	int r;
	unsigned int i;

	if (argc < 2) {
		ti->error = "Not enough arguments";
		return -EINVAL;
	}

	stripes = simple_strtoul(argv[0], &end, 10);
	if (!stripes || *end) {
		ti->error = "Invalid stripe count";
		return -EINVAL;
	}

	chunk_size = simple_strtoul(argv[1], &end, 10);
	if (*end) {
		ti->error = "Invalid chunk_size";
		return -EINVAL;
	}

	/*
	 * chunk_size is a power of two
	 */
	if (!is_power_of_2(chunk_size) ||
	    (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
		ti->error = "Invalid chunk size";
		return -EINVAL;
	}

	if (ti->len & (chunk_size - 1)) {
		ti->error = "Target length not divisible by "
		    "chunk size";
		return -EINVAL;
	}

	width = ti->len;
	if (sector_div(width, stripes)) {
		ti->error = "Target length not divisible by "
		    "number of stripes";
		return -EINVAL;
	}

	/*
	 * Do we have enough arguments for that many stripes ?
	 */
	if (argc != (2 + 2 * stripes)) {
		ti->error = "Not enough destinations "
			"specified";
		return -EINVAL;
	}

	sc = alloc_context(stripes);
	if (!sc) {
		ti->error = "Memory allocation for striped context "
		    "failed";
		return -ENOMEM;
	}

	INIT_WORK(&sc->kstriped_ws, trigger_event);

	/* Set pointer to dm target; used in trigger_event */
	sc->ti = ti;

	sc->stripes = stripes;
	sc->stripe_width = width;
	ti->split_io = chunk_size;
	ti->num_flush_requests = stripes;

	sc->chunk_mask = ((sector_t) chunk_size) - 1;
	for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
		chunk_size >>= 1;
	sc->chunk_shift--;

	/*
	 * Get the stripe destinations.
	 */
	for (i = 0; i < stripes; i++) {
		argv += 2;

		r = get_stripe(ti, sc, i, argv);
		if (r < 0) {
			ti->error = "Couldn't parse stripe destination";
			while (i--)
				dm_put_device(ti, sc->stripe[i].dev);
			kfree(sc);
			return r;
		}
		atomic_set(&(sc->stripe[i].error_count), 0);
	}

	ti->private = sc;

	return 0;
}

static void stripe_dtr(struct dm_target *ti)
{
	unsigned int i;
	struct stripe_c *sc = (struct stripe_c *) ti->private;

	for (i = 0; i < sc->stripes; i++)
		dm_put_device(ti, sc->stripe[i].dev);

	flush_workqueue(kstriped);
	kfree(sc);
}

static int stripe_map(struct dm_target *ti, struct bio *bio,
		      union map_info *map_context)
{
	struct stripe_c *sc = (struct stripe_c *) ti->private;
	sector_t offset, chunk;
	uint32_t stripe;
	unsigned target_request_nr;

	if (unlikely(bio_empty_barrier(bio))) {
		target_request_nr = map_context->target_request_nr;
		BUG_ON(target_request_nr >= sc->stripes);
		bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
		return DM_MAPIO_REMAPPED;
	}

	offset = dm_target_offset(ti, bio->bi_sector);
	chunk = offset >> sc->chunk_shift;
	stripe = sector_div(chunk, sc->stripes);

	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
	bio->bi_sector = sc->stripe[stripe].physical_start +
	    (chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
	return DM_MAPIO_REMAPPED;
}

/*
 * Stripe status:
 *
 * INFO
 * #stripes [stripe_name <stripe_name>] [group word count]
 * [error count 'A|D' <error count 'A|D'>]
 *
 * TABLE
 * #stripes [stripe chunk size]
 * [stripe_name physical_start <stripe_name physical_start>]
 *
 */

static int stripe_status(struct dm_target *ti,
			 status_type_t type, char *result, unsigned int maxlen)
{
	struct stripe_c *sc = (struct stripe_c *) ti->private;
	char buffer[sc->stripes + 1];
	unsigned int sz = 0;
	unsigned int i;

	switch (type) {
	case STATUSTYPE_INFO:
		DMEMIT("%d ", sc->stripes);
		for (i = 0; i < sc->stripes; i++)  {
			DMEMIT("%s ", sc->stripe[i].dev->name);
			buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
				'D' : 'A';
		}
		buffer[i] = '\0';
		DMEMIT("1 %s", buffer);
		break;

	case STATUSTYPE_TABLE:
		DMEMIT("%d %llu", sc->stripes,
			(unsigned long long)sc->chunk_mask + 1);
		for (i = 0; i < sc->stripes; i++)
			DMEMIT(" %s %llu", sc->stripe[i].dev->name,
			    (unsigned long long)sc->stripe[i].physical_start);
		break;
	}
	return 0;
}

static int stripe_end_io(struct dm_target *ti, struct bio *bio,
			 int error, union map_info *map_context)
{
	unsigned i;
	char major_minor[16];
	struct stripe_c *sc = ti->private;

	if (!error)
		return 0; /* I/O complete */

	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
		return error;

	if (error == -EOPNOTSUPP)
		return error;

	memset(major_minor, 0, sizeof(major_minor));
	sprintf(major_minor, "%d:%d",
		MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
		MINOR(disk_devt(bio->bi_bdev->bd_disk)));

	/*
	 * Test to see which stripe drive triggered the event
	 * and increment error count for all stripes on that device.
	 * If the error count for a given device exceeds the threshold
	 * value we will no longer trigger any further events.
	 */
	for (i = 0; i < sc->stripes; i++)
		if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
			atomic_inc(&(sc->stripe[i].error_count));
			if (atomic_read(&(sc->stripe[i].error_count)) <
			    DM_IO_ERROR_THRESHOLD)
				queue_work(kstriped, &sc->kstriped_ws);
		}

	return error;
}

static int stripe_iterate_devices(struct dm_target *ti,
				  iterate_devices_callout_fn fn, void *data)
{
	struct stripe_c *sc = ti->private;
	int ret = 0;
	unsigned i = 0;

	do {
		ret = fn(ti, sc->stripe[i].dev,
			 sc->stripe[i].physical_start,
			 sc->stripe_width, data);
	} while (!ret && ++i < sc->stripes);

	return ret;
}

static void stripe_io_hints(struct dm_target *ti,
			    struct queue_limits *limits)
{
	struct stripe_c *sc = ti->private;
	unsigned chunk_size = (sc->chunk_mask + 1) << 9;

	blk_limits_io_min(limits, chunk_size);
	blk_limits_io_opt(limits, chunk_size * sc->stripes);
}

static struct target_type stripe_target = {
	.name   = "striped",
	.version = {1, 3, 0},
	.module = THIS_MODULE,
	.ctr    = stripe_ctr,
	.dtr    = stripe_dtr,
	.map    = stripe_map,
	.end_io = stripe_end_io,
	.status = stripe_status,
	.iterate_devices = stripe_iterate_devices,
	.io_hints = stripe_io_hints,
};

int __init dm_stripe_init(void)
{
	int r;

	r = dm_register_target(&stripe_target);
	if (r < 0) {
		DMWARN("target registration failed");
		return r;
	}

	kstriped = create_singlethread_workqueue("kstriped");
	if (!kstriped) {
		DMERR("failed to create workqueue kstriped");
		dm_unregister_target(&stripe_target);
		return -ENOMEM;
	}

	return r;
}

void dm_stripe_exit(void)
{
	dm_unregister_target(&stripe_target);
	destroy_workqueue(kstriped);

	return;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright (C) 2001-2003 Sistina Software (UK) Limited.
	3	*
	4	* This file is released under the GPL.
	5	*/
	6
586e80e6	7	#include <linux/device-mapper.h>
1da177e4 LT	8
	9	#include <linux/module.h>
	10	#include <linux/init.h>
	11	#include <linux/blkdev.h>
	12	#include <linux/bio.h>
	13	#include <linux/slab.h>
6f3c3f0a	14	#include <linux/log2.h>
1da177e4	15
72d94861	16	#define DM_MSG_PREFIX "striped"
a25eb944	17	#define DM_IO_ERROR_THRESHOLD 15
72d94861	18
1da177e4 LT	19	struct stripe {
	20	struct dm_dev *dev;
	21	sector_t physical_start;
a25eb944 BW	22
a25eb944 BW	23	atomic_t error_count;
1da177e4 LT	24	};
	25
	26	struct stripe_c {
	27	uint32_t stripes;
	28
	29	/* The size of this target / num. stripes */
	30	sector_t stripe_width;
	31
	32	/* stripe chunk size */
	33	uint32_t chunk_shift;
	34	sector_t chunk_mask;
	35
a25eb944 BW	36	/* Needed for handling events */
	37	struct dm_target *ti;
	38
	39	/* Work struct used for triggering events*/
	40	struct work_struct kstriped_ws;
	41
1da177e4 LT	42	struct stripe stripe[0];
	43	};
	44
a25eb944 BW	45	static struct workqueue_struct *kstriped;
	46
	47	/*
	48	* An event is triggered whenever a drive
	49	* drops out of a stripe volume.
	50	*/
	51	static void trigger_event(struct work_struct *work)
	52	{
	53	struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws);
	54
	55	dm_table_event(sc->ti->table);
	56
	57	}
	58
1da177e4 LT	59	static inline struct stripe_c *alloc_context(unsigned int stripes)
	60	{
	61	size_t len;
	62
d63a5ce3 MP	63	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	64	stripes))
1da177e4 LT	65	return NULL;
	66
	67	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	68
	69	return kmalloc(len, GFP_KERNEL);
	70	}
	71
	72	/*
	73	* Parse a single <dev> <sector> pair
	74	*/
	75	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	76	unsigned int stripe, char **argv)
	77	{
4ee218cd	78	unsigned long long start;
1da177e4	79
4ee218cd	80	if (sscanf(argv[1], "%llu", &start) != 1)
1da177e4 LT	81	return -EINVAL;
1da177e4 LT	82
8215d6ec	83	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
1da177e4 LT	84	&sc->stripe[stripe].dev))
	85	return -ENXIO;
	86
	87	sc->stripe[stripe].physical_start = start;
a25eb944	88
1da177e4 LT	89	return 0;
	90	}
	91
	92	/*
	93	* Construct a striped mapping.
	94	* <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
	95	*/
	96	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	97	{
	98	struct stripe_c *sc;
	99	sector_t width;
	100	uint32_t stripes;
	101	uint32_t chunk_size;
	102	char *end;
	103	int r;
	104	unsigned int i;
	105
	106	if (argc < 2) {
72d94861	107	ti->error = "Not enough arguments";
1da177e4 LT	108	return -EINVAL;
	109	}
	110
	111	stripes = simple_strtoul(argv[0], &end, 10);
781248c1	112	if (!stripes \|\| *end) {
72d94861	113	ti->error = "Invalid stripe count";
1da177e4 LT	114	return -EINVAL;
	115	}
	116
	117	chunk_size = simple_strtoul(argv[1], &end, 10);
	118	if (*end) {
72d94861	119	ti->error = "Invalid chunk_size";
1da177e4 LT	120	return -EINVAL;
	121	}
	122
	123	/*
	124	* chunk_size is a power of two
	125	*/
6f3c3f0a	126	if (!is_power_of_2(chunk_size) \|\|
1da177e4	127	(chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
72d94861	128	ti->error = "Invalid chunk size";
1da177e4 LT	129	return -EINVAL;
	130	}
	131
a22c96c7	132	if (ti->len & (chunk_size - 1)) {
72d94861	133	ti->error = "Target length not divisible by "
8ba32fde KC	134	"chunk size";
	135	return -EINVAL;
	136	}
	137
1da177e4 LT	138	width = ti->len;
1da177e4 LT	139	if (sector_div(width, stripes)) {
72d94861	140	ti->error = "Target length not divisible by "
1da177e4 LT	141	"number of stripes";
	142	return -EINVAL;
	143	}
	144
	145	/*
	146	* Do we have enough arguments for that many stripes ?
	147	*/
	148	if (argc != (2 + 2 * stripes)) {
72d94861	149	ti->error = "Not enough destinations "
1da177e4 LT	150	"specified";
	151	return -EINVAL;
	152	}
	153
	154	sc = alloc_context(stripes);
	155	if (!sc) {
72d94861	156	ti->error = "Memory allocation for striped context "
1da177e4 LT	157	"failed";
	158	return -ENOMEM;
	159	}
	160
a25eb944 BW	161	INIT_WORK(&sc->kstriped_ws, trigger_event);
	162
	163	/* Set pointer to dm target; used in trigger_event */
	164	sc->ti = ti;
	165
1da177e4 LT	166	sc->stripes = stripes;
	167	sc->stripe_width = width;
	168	ti->split_io = chunk_size;
374bf7e7	169	ti->num_flush_requests = stripes;
1da177e4 LT	170
	171	sc->chunk_mask = ((sector_t) chunk_size) - 1;
	172	for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
	173	chunk_size >>= 1;
	174	sc->chunk_shift--;
	175
	176	/*
	177	* Get the stripe destinations.
	178	*/
	179	for (i = 0; i < stripes; i++) {
	180	argv += 2;
	181
	182	r = get_stripe(ti, sc, i, argv);
	183	if (r < 0) {
72d94861	184	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	185	while (i--)
	186	dm_put_device(ti, sc->stripe[i].dev);
	187	kfree(sc);
	188	return r;
	189	}
a25eb944	190	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	191	}
	192
	193	ti->private = sc;
a25eb944	194
1da177e4 LT	195	return 0;
	196	}
	197
	198	static void stripe_dtr(struct dm_target *ti)
	199	{
	200	unsigned int i;
	201	struct stripe_c sc = (struct stripe_c ) ti->private;
	202
	203	for (i = 0; i < sc->stripes; i++)
	204	dm_put_device(ti, sc->stripe[i].dev);
	205
a25eb944	206	flush_workqueue(kstriped);
1da177e4 LT	207	kfree(sc);
	208	}
	209
	210	static int stripe_map(struct dm_target ti, struct bio bio,
	211	union map_info *map_context)
	212	{
	213	struct stripe_c sc = (struct stripe_c ) ti->private;
374bf7e7 MP	214	sector_t offset, chunk;
374bf7e7 MP	215	uint32_t stripe;
57cba5d3	216	unsigned target_request_nr;
1da177e4	217
374bf7e7	218	if (unlikely(bio_empty_barrier(bio))) {
57cba5d3 MS	219	target_request_nr = map_context->target_request_nr;
	220	BUG_ON(target_request_nr >= sc->stripes);
	221	bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
374bf7e7 MP	222	return DM_MAPIO_REMAPPED;
	223	}
	224
b441a262	225	offset = dm_target_offset(ti, bio->bi_sector);
374bf7e7 MP	226	chunk = offset >> sc->chunk_shift;
374bf7e7 MP	227	stripe = sector_div(chunk, sc->stripes);
1da177e4 LT	228
	229	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
	230	bio->bi_sector = sc->stripe[stripe].physical_start +
	231	(chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
d2a7ad29	232	return DM_MAPIO_REMAPPED;
1da177e4 LT	233	}
1da177e4 LT	234
4f7f5c67 BW	235	/*
	236	* Stripe status:
	237	*
	238	* INFO
	239	* #stripes [stripe_name <stripe_name>] [group word count]
	240	* [error count 'A\|D' <error count 'A\|D'>]
	241	*
	242	* TABLE
	243	* #stripes [stripe chunk size]
	244	* [stripe_name physical_start <stripe_name physical_start>]
	245	*
	246	*/
	247
1da177e4 LT	248	static int stripe_status(struct dm_target *ti,
	249	status_type_t type, char *result, unsigned int maxlen)
	250	{
	251	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	252	char buffer[sc->stripes + 1];
1da177e4 LT	253	unsigned int sz = 0;
	254	unsigned int i;
	255
	256	switch (type) {
	257	case STATUSTYPE_INFO:
4f7f5c67 BW	258	DMEMIT("%d ", sc->stripes);
	259	for (i = 0; i < sc->stripes; i++) {
	260	DMEMIT("%s ", sc->stripe[i].dev->name);
	261	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	262	'D' : 'A';
	263	}
	264	buffer[i] = '\0';
	265	DMEMIT("1 %s", buffer);
1da177e4 LT	266	break;
	267
	268	case STATUSTYPE_TABLE:
4ee218cd AM	269	DMEMIT("%d %llu", sc->stripes,
4ee218cd AM	270	(unsigned long long)sc->chunk_mask + 1);
1da177e4	271	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	272	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	273	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	274	break;
	275	}
	276	return 0;
	277	}
	278
a25eb944 BW	279	static int stripe_end_io(struct dm_target ti, struct bio bio,
	280	int error, union map_info *map_context)
	281	{
	282	unsigned i;
	283	char major_minor[16];
	284	struct stripe_c *sc = ti->private;
	285
	286	if (!error)
	287	return 0; /* I/O complete */
	288
7b6d91da	289	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	290	return error;
	291
	292	if (error == -EOPNOTSUPP)
	293	return error;
	294
	295	memset(major_minor, 0, sizeof(major_minor));
	296	sprintf(major_minor, "%d:%d",
f331c029 TH	297	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	298	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	299
	300	/*
	301	* Test to see which stripe drive triggered the event
	302	* and increment error count for all stripes on that device.
	303	* If the error count for a given device exceeds the threshold
	304	* value we will no longer trigger any further events.
	305	*/
	306	for (i = 0; i < sc->stripes; i++)
	307	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	308	atomic_inc(&(sc->stripe[i].error_count));
	309	if (atomic_read(&(sc->stripe[i].error_count)) <
	310	DM_IO_ERROR_THRESHOLD)
	311	queue_work(kstriped, &sc->kstriped_ws);
	312	}
	313
	314	return error;
	315	}
	316
af4874e0 MS	317	static int stripe_iterate_devices(struct dm_target *ti,
	318	iterate_devices_callout_fn fn, void *data)
	319	{
	320	struct stripe_c *sc = ti->private;
	321	int ret = 0;
	322	unsigned i = 0;
	323
5dea271b	324	do {
af4874e0	325	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	326	sc->stripe[i].physical_start,
	327	sc->stripe_width, data);
	328	} while (!ret && ++i < sc->stripes);
af4874e0 MS	329
	330	return ret;
	331	}
	332
40bea431 MS	333	static void stripe_io_hints(struct dm_target *ti,
	334	struct queue_limits *limits)
	335	{
	336	struct stripe_c *sc = ti->private;
	337	unsigned chunk_size = (sc->chunk_mask + 1) << 9;
	338
	339	blk_limits_io_min(limits, chunk_size);
3c5820c7	340	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	341	}
40bea431 MS	342
1da177e4 LT	343	static struct target_type stripe_target = {
1da177e4 LT	344	.name = "striped",
40bea431	345	.version = {1, 3, 0},
1da177e4 LT	346	.module = THIS_MODULE,
	347	.ctr = stripe_ctr,
	348	.dtr = stripe_dtr,
	349	.map = stripe_map,
a25eb944	350	.end_io = stripe_end_io,
1da177e4	351	.status = stripe_status,
af4874e0	352	.iterate_devices = stripe_iterate_devices,
40bea431	353	.io_hints = stripe_io_hints,
1da177e4 LT	354	};
	355
	356	int __init dm_stripe_init(void)
	357	{
	358	int r;
	359
	360	r = dm_register_target(&stripe_target);
6edebdee	361	if (r < 0) {
72d94861	362	DMWARN("target registration failed");
6edebdee HM	363	return r;
6edebdee HM	364	}
1da177e4	365
a25eb944 BW	366	kstriped = create_singlethread_workqueue("kstriped");
	367	if (!kstriped) {
	368	DMERR("failed to create workqueue kstriped");
	369	dm_unregister_target(&stripe_target);
	370	return -ENOMEM;
	371	}
	372
1da177e4 LT	373	return r;
	374	}
	375
	376	void dm_stripe_exit(void)
	377	{
10d3bd09	378	dm_unregister_target(&stripe_target);
a25eb944 BW	379	destroy_workqueue(kstriped);
a25eb944 BW	380
1da177e4 LT	381	return;
1da177e4 LT	382	}