[linux-block.git] / drivers / md / dm-delay.c

/*
 * Copyright (C) 2005-2007 Red Hat GmbH
 *
 * A target that delays reads and/or writes and can send
 * them to different devices.
 *
 * This file is released under the GPL.
 */

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

#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "delay"

struct delay_class {
	struct dm_dev *dev;
	sector_t start;
	unsigned delay;
	unsigned ops;
};

struct delay_c {
	struct timer_list delay_timer;
	struct mutex timer_lock;
	struct workqueue_struct *kdelayd_wq;
	struct work_struct flush_expired_bios;
	struct list_head delayed_bios;
	atomic_t may_delay;

	struct delay_class read;
	struct delay_class write;
	struct delay_class flush;

	int argc;
};

struct dm_delay_info {
	struct delay_c *context;
	struct delay_class *class;
	struct list_head list;
	unsigned long expires;
};

static DEFINE_MUTEX(delayed_bios_lock);

static void handle_delayed_timer(struct timer_list *t)
{
	struct delay_c *dc = from_timer(dc, t, delay_timer);

	queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
}

static void queue_timeout(struct delay_c *dc, unsigned long expires)
{
	mutex_lock(&dc->timer_lock);

	if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
		mod_timer(&dc->delay_timer, expires);

	mutex_unlock(&dc->timer_lock);
}

static void flush_bios(struct bio *bio)
{
	struct bio *n;

	while (bio) {
		n = bio->bi_next;
		bio->bi_next = NULL;
		generic_make_request(bio);
		bio = n;
	}
}

static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
{
	struct dm_delay_info *delayed, *next;
	unsigned long next_expires = 0;
	unsigned long start_timer = 0;
	struct bio_list flush_bios = { };

	mutex_lock(&delayed_bios_lock);
	list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
		if (flush_all || time_after_eq(jiffies, delayed->expires)) {
			struct bio *bio = dm_bio_from_per_bio_data(delayed,
						sizeof(struct dm_delay_info));
			list_del(&delayed->list);
			bio_list_add(&flush_bios, bio);
			delayed->class->ops--;
			continue;
		}

		if (!start_timer) {
			start_timer = 1;
			next_expires = delayed->expires;
		} else
			next_expires = min(next_expires, delayed->expires);
	}
	mutex_unlock(&delayed_bios_lock);

	if (start_timer)
		queue_timeout(dc, next_expires);

	return bio_list_get(&flush_bios);
}

static void flush_expired_bios(struct work_struct *work)
{
	struct delay_c *dc;

	dc = container_of(work, struct delay_c, flush_expired_bios);
	flush_bios(flush_delayed_bios(dc, 0));
}

static void delay_dtr(struct dm_target *ti)
{
	struct delay_c *dc = ti->private;

	if (dc->kdelayd_wq)
		destroy_workqueue(dc->kdelayd_wq);

	if (dc->read.dev)
		dm_put_device(ti, dc->read.dev);
	if (dc->write.dev)
		dm_put_device(ti, dc->write.dev);
	if (dc->flush.dev)
		dm_put_device(ti, dc->flush.dev);

	mutex_destroy(&dc->timer_lock);

	kfree(dc);
}

static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **argv)
{
	int ret;
	unsigned long long tmpll;
	char dummy;

	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
		ti->error = "Invalid device sector";
		return -EINVAL;
	}
	c->start = tmpll;

	if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) {
		ti->error = "Invalid delay";
		return -EINVAL;
	}

	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev);
	if (ret) {
		ti->error = "Device lookup failed";
		return ret;
	}

	return 0;
}

/*
 * Mapping parameters:
 *    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
 *
 * With separate write parameters, the first set is only used for reads.
 * Offsets are specified in sectors.
 * Delays are specified in milliseconds.
 */
static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct delay_c *dc;
	int ret;

	if (argc != 3 && argc != 6 && argc != 9) {
		ti->error = "Requires exactly 3, 6 or 9 arguments";
		return -EINVAL;
	}

	dc = kzalloc(sizeof(*dc), GFP_KERNEL);
	if (!dc) {
		ti->error = "Cannot allocate context";
		return -ENOMEM;
	}

	ti->private = dc;
	timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
	INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
	INIT_LIST_HEAD(&dc->delayed_bios);
	mutex_init(&dc->timer_lock);
	atomic_set(&dc->may_delay, 1);
	dc->argc = argc;

	ret = delay_class_ctr(ti, &dc->read, argv);
	if (ret)
		goto bad;

	if (argc == 3) {
		ret = delay_class_ctr(ti, &dc->write, argv);
		if (ret)
			goto bad;
		ret = delay_class_ctr(ti, &dc->flush, argv);
		if (ret)
			goto bad;
		goto out;
	}

	ret = delay_class_ctr(ti, &dc->write, argv + 3);
	if (ret)
		goto bad;
	if (argc == 6) {
		ret = delay_class_ctr(ti, &dc->flush, argv + 3);
		if (ret)
			goto bad;
		goto out;
	}

	ret = delay_class_ctr(ti, &dc->flush, argv + 6);
	if (ret)
		goto bad;

out:
	dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
	if (!dc->kdelayd_wq) {
		ret = -EINVAL;
		DMERR("Couldn't start kdelayd");
		goto bad;
	}

	ti->num_flush_bios = 1;
	ti->num_discard_bios = 1;
	ti->per_io_data_size = sizeof(struct dm_delay_info);
	return 0;

bad:
	delay_dtr(ti);
	return ret;
}

static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
{
	struct dm_delay_info *delayed;
	unsigned long expires = 0;

	if (!c->delay || !atomic_read(&dc->may_delay))
		return DM_MAPIO_REMAPPED;

	delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));

	delayed->context = dc;
	delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);

	mutex_lock(&delayed_bios_lock);
	c->ops++;
	list_add_tail(&delayed->list, &dc->delayed_bios);
	mutex_unlock(&delayed_bios_lock);

	queue_timeout(dc, expires);

	return DM_MAPIO_SUBMITTED;
}

static void delay_presuspend(struct dm_target *ti)
{
	struct delay_c *dc = ti->private;

	atomic_set(&dc->may_delay, 0);
	del_timer_sync(&dc->delay_timer);
	flush_bios(flush_delayed_bios(dc, 1));
}

static void delay_resume(struct dm_target *ti)
{
	struct delay_c *dc = ti->private;

	atomic_set(&dc->may_delay, 1);
}

static int delay_map(struct dm_target *ti, struct bio *bio)
{
	struct delay_c *dc = ti->private;
	struct delay_class *c;
	struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));

	if (bio_data_dir(bio) == WRITE) {
		if (unlikely(bio->bi_opf & REQ_PREFLUSH))
			c = &dc->flush;
		else
			c = &dc->write;
	} else {
		c = &dc->read;
	}
	delayed->class = c;
	bio_set_dev(bio, c->dev->bdev);
	if (bio_sectors(bio))
		bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector);

	return delay_bio(dc, c, bio);
}

#define DMEMIT_DELAY_CLASS(c) \
	DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)

static void delay_status(struct dm_target *ti, status_type_t type,
			 unsigned status_flags, char *result, unsigned maxlen)
{
	struct delay_c *dc = ti->private;
	int sz = 0;

	switch (type) {
	case STATUSTYPE_INFO:
		DMEMIT("%u %u %u", dc->read.ops, dc->write.ops, dc->flush.ops);
		break;

	case STATUSTYPE_TABLE:
		DMEMIT_DELAY_CLASS(&dc->read);
		if (dc->argc >= 6) {
			DMEMIT(" ");
			DMEMIT_DELAY_CLASS(&dc->write);
		}
		if (dc->argc >= 9) {
			DMEMIT(" ");
			DMEMIT_DELAY_CLASS(&dc->flush);
		}
		break;
	}
}

static int delay_iterate_devices(struct dm_target *ti,
				 iterate_devices_callout_fn fn, void *data)
{
	struct delay_c *dc = ti->private;
	int ret = 0;

	ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data);
	if (ret)
		goto out;
	ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data);
	if (ret)
		goto out;
	ret = fn(ti, dc->flush.dev, dc->flush.start, ti->len, data);
	if (ret)
		goto out;

out:
	return ret;
}

static struct target_type delay_target = {
	.name	     = "delay",
	.version     = {1, 2, 1},
	.features    = DM_TARGET_PASSES_INTEGRITY,
	.module      = THIS_MODULE,
	.ctr	     = delay_ctr,
	.dtr	     = delay_dtr,
	.map	     = delay_map,
	.presuspend  = delay_presuspend,
	.resume	     = delay_resume,
	.status	     = delay_status,
	.iterate_devices = delay_iterate_devices,
};

static int __init dm_delay_init(void)
{
	int r;

	r = dm_register_target(&delay_target);
	if (r < 0) {
		DMERR("register failed %d", r);
		goto bad_register;
	}

	return 0;

bad_register:
	return r;
}

static void __exit dm_delay_exit(void)
{
	dm_unregister_target(&delay_target);
}

/* Module hooks */
module_init(dm_delay_init);
module_exit(dm_delay_exit);

MODULE_DESCRIPTION(DM_NAME " delay target");
MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
26b9f228 HM	1	/*
	2	* Copyright (C) 2005-2007 Red Hat GmbH
	3	*
	4	* A target that delays reads and/or writes and can send
	5	* them to different devices.
	6	*
	7	* This file is released under the GPL.
	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/init.h>
	12	#include <linux/blkdev.h>
	13	#include <linux/bio.h>
	14	#include <linux/slab.h>
	15
586e80e6 MP	16	#include <linux/device-mapper.h>
586e80e6 MP	17
26b9f228 HM	18	#define DM_MSG_PREFIX "delay"
26b9f228 HM	19
3876ac76 MP	20	struct delay_class {
	21	struct dm_dev *dev;
	22	sector_t start;
	23	unsigned delay;
	24	unsigned ops;
	25	};
	26
26b9f228 HM	27	struct delay_c {
26b9f228 HM	28	struct timer_list delay_timer;
ac818646	29	struct mutex timer_lock;
718822c1	30	struct workqueue_struct *kdelayd_wq;
26b9f228 HM	31	struct work_struct flush_expired_bios;
	32	struct list_head delayed_bios;
	33	atomic_t may_delay;
26b9f228	34
3876ac76 MP	35	struct delay_class read;
3876ac76 MP	36	struct delay_class write;
cda6b5ab	37	struct delay_class flush;
26b9f228	38
3876ac76	39	int argc;
26b9f228 HM	40	};
26b9f228 HM	41
028867ac	42	struct dm_delay_info {
26b9f228	43	struct delay_c *context;
3876ac76	44	struct delay_class *class;
26b9f228	45	struct list_head list;
26b9f228 HM	46	unsigned long expires;
	47	};
	48
	49	static DEFINE_MUTEX(delayed_bios_lock);
	50
8376d3c1	51	static void handle_delayed_timer(struct timer_list *t)
26b9f228	52	{
8376d3c1	53	struct delay_c *dc = from_timer(dc, t, delay_timer);
26b9f228	54
718822c1	55	queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
26b9f228 HM	56	}
	57
	58	static void queue_timeout(struct delay_c *dc, unsigned long expires)
	59	{
ac818646	60	mutex_lock(&dc->timer_lock);
26b9f228 HM	61
	62	if (!timer_pending(&dc->delay_timer) \|\| expires < dc->delay_timer.expires)
	63	mod_timer(&dc->delay_timer, expires);
	64
ac818646	65	mutex_unlock(&dc->timer_lock);
26b9f228 HM	66	}
	67
	68	static void flush_bios(struct bio *bio)
	69	{
	70	struct bio *n;
	71
	72	while (bio) {
	73	n = bio->bi_next;
	74	bio->bi_next = NULL;
	75	generic_make_request(bio);
	76	bio = n;
	77	}
	78	}
	79
	80	static struct bio flush_delayed_bios(struct delay_c dc, int flush_all)
	81	{
028867ac	82	struct dm_delay_info delayed, next;
26b9f228	83	unsigned long next_expires = 0;
3876ac76	84	unsigned long start_timer = 0;
051814c6	85	struct bio_list flush_bios = { };
26b9f228 HM	86
	87	mutex_lock(&delayed_bios_lock);
	88	list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
	89	if (flush_all \|\| time_after_eq(jiffies, delayed->expires)) {
42065460 MP	90	struct bio *bio = dm_bio_from_per_bio_data(delayed,
42065460 MP	91	sizeof(struct dm_delay_info));
26b9f228	92	list_del(&delayed->list);
42065460	93	bio_list_add(&flush_bios, bio);
3876ac76	94	delayed->class->ops--;
26b9f228 HM	95	continue;
	96	}
	97
	98	if (!start_timer) {
	99	start_timer = 1;
	100	next_expires = delayed->expires;
	101	} else
	102	next_expires = min(next_expires, delayed->expires);
	103	}
26b9f228 HM	104	mutex_unlock(&delayed_bios_lock);
	105
	106	if (start_timer)
	107	queue_timeout(dc, next_expires);
	108
	109	return bio_list_get(&flush_bios);
	110	}
	111
	112	static void flush_expired_bios(struct work_struct *work)
	113	{
	114	struct delay_c *dc;
	115
	116	dc = container_of(work, struct delay_c, flush_expired_bios);
	117	flush_bios(flush_delayed_bios(dc, 0));
	118	}
	119
3876ac76 MP	120	static void delay_dtr(struct dm_target *ti)
	121	{
	122	struct delay_c *dc = ti->private;
	123
81bc6d15 MP	124	if (dc->kdelayd_wq)
81bc6d15 MP	125	destroy_workqueue(dc->kdelayd_wq);
3876ac76 MP	126
	127	if (dc->read.dev)
	128	dm_put_device(ti, dc->read.dev);
	129	if (dc->write.dev)
	130	dm_put_device(ti, dc->write.dev);
cda6b5ab MP	131	if (dc->flush.dev)
cda6b5ab MP	132	dm_put_device(ti, dc->flush.dev);
3876ac76 MP	133
	134	mutex_destroy(&dc->timer_lock);
	135
	136	kfree(dc);
	137	}
	138
	139	static int delay_class_ctr(struct dm_target ti, struct delay_class c, char **argv)
	140	{
	141	int ret;
	142	unsigned long long tmpll;
	143	char dummy;
	144
ef87bfc2	145	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 \|\| tmpll != (sector_t)tmpll) {
3876ac76 MP	146	ti->error = "Invalid device sector";
	147	return -EINVAL;
	148	}
	149	c->start = tmpll;
	150
	151	if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) {
	152	ti->error = "Invalid delay";
	153	return -EINVAL;
	154	}
	155
	156	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev);
	157	if (ret) {
	158	ti->error = "Device lookup failed";
	159	return ret;
	160	}
	161
	162	return 0;
	163	}
	164
26b9f228 HM	165	/*
	166	* Mapping parameters:
	167	* <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
	168	*
	169	* With separate write parameters, the first set is only used for reads.
f49e869a	170	* Offsets are specified in sectors.
26b9f228 HM	171	* Delays are specified in milliseconds.
	172	*/
	173	static int delay_ctr(struct dm_target ti, unsigned int argc, char *argv)
	174	{
	175	struct delay_c *dc;
e80d1c80	176	int ret;
26b9f228	177
cda6b5ab MP	178	if (argc != 3 && argc != 6 && argc != 9) {
cda6b5ab MP	179	ti->error = "Requires exactly 3, 6 or 9 arguments";
26b9f228 HM	180	return -EINVAL;
	181	}
	182
3876ac76	183	dc = kzalloc(sizeof(*dc), GFP_KERNEL);
26b9f228 HM	184	if (!dc) {
	185	ti->error = "Cannot allocate context";
	186	return -ENOMEM;
	187	}
	188
3876ac76 MP	189	ti->private = dc;
	190	timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
	191	INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
	192	INIT_LIST_HEAD(&dc->delayed_bios);
	193	mutex_init(&dc->timer_lock);
	194	atomic_set(&dc->may_delay, 1);
	195	dc->argc = argc;
26b9f228	196
3876ac76 MP	197	ret = delay_class_ctr(ti, &dc->read, argv);
3876ac76 MP	198	if (ret)
26b9f228	199	goto bad;
26b9f228	200
3876ac76 MP	201	if (argc == 3) {
3876ac76 MP	202	ret = delay_class_ctr(ti, &dc->write, argv);
cda6b5ab MP	203	if (ret)
	204	goto bad;
	205	ret = delay_class_ctr(ti, &dc->flush, argv);
3876ac76 MP	206	if (ret)
3876ac76 MP	207	goto bad;
26b9f228	208	goto out;
26b9f228	209	}
26b9f228	210
3876ac76 MP	211	ret = delay_class_ctr(ti, &dc->write, argv + 3);
	212	if (ret)
	213	goto bad;
cda6b5ab MP	214	if (argc == 6) {
	215	ret = delay_class_ctr(ti, &dc->flush, argv + 3);
	216	if (ret)
	217	goto bad;
	218	goto out;
	219	}
	220
	221	ret = delay_class_ctr(ti, &dc->flush, argv + 6);
	222	if (ret)
	223	goto bad;
26b9f228 HM	224
26b9f228 HM	225	out:
718822c1 MP	226	dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
718822c1 MP	227	if (!dc->kdelayd_wq) {
3876ac76	228	ret = -EINVAL;
718822c1	229	DMERR("Couldn't start kdelayd");
3876ac76	230	goto bad;
718822c1 MP	231	}
718822c1 MP	232
55a62eef AK	233	ti->num_flush_bios = 1;
55a62eef AK	234	ti->num_discard_bios = 1;
30187e1d	235	ti->per_io_data_size = sizeof(struct dm_delay_info);
26b9f228 HM	236	return 0;
	237
	238	bad:
3876ac76	239	delay_dtr(ti);
e80d1c80	240	return ret;
26b9f228 HM	241	}
26b9f228 HM	242
3876ac76	243	static int delay_bio(struct delay_c dc, struct delay_class c, struct bio *bio)
26b9f228	244	{
028867ac	245	struct dm_delay_info *delayed;
26b9f228 HM	246	unsigned long expires = 0;
26b9f228 HM	247
3876ac76	248	if (!c->delay \|\| !atomic_read(&dc->may_delay))
340c9ec0	249	return DM_MAPIO_REMAPPED;
26b9f228	250
42065460	251	delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
26b9f228 HM	252
26b9f228 HM	253	delayed->context = dc;
3876ac76	254	delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);
26b9f228 HM	255
26b9f228 HM	256	mutex_lock(&delayed_bios_lock);
3876ac76	257	c->ops++;
26b9f228	258	list_add_tail(&delayed->list, &dc->delayed_bios);
26b9f228 HM	259	mutex_unlock(&delayed_bios_lock);
	260
	261	queue_timeout(dc, expires);
	262
340c9ec0	263	return DM_MAPIO_SUBMITTED;
26b9f228 HM	264	}
	265
	266	static void delay_presuspend(struct dm_target *ti)
	267	{
	268	struct delay_c *dc = ti->private;
	269
	270	atomic_set(&dc->may_delay, 0);
	271	del_timer_sync(&dc->delay_timer);
	272	flush_bios(flush_delayed_bios(dc, 1));
	273	}
	274
	275	static void delay_resume(struct dm_target *ti)
	276	{
	277	struct delay_c *dc = ti->private;
	278
	279	atomic_set(&dc->may_delay, 1);
	280	}
	281
7de3ee57	282	static int delay_map(struct dm_target ti, struct bio bio)
26b9f228 HM	283	{
26b9f228 HM	284	struct delay_c *dc = ti->private;
3876ac76 MP	285	struct delay_class *c;
3876ac76 MP	286	struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
26b9f228	287
3876ac76	288	if (bio_data_dir(bio) == WRITE) {
cda6b5ab MP	289	if (unlikely(bio->bi_opf & REQ_PREFLUSH))
	290	c = &dc->flush;
	291	else
	292	c = &dc->write;
3876ac76 MP	293	} else {
3876ac76 MP	294	c = &dc->read;
26b9f228	295	}
3876ac76 MP	296	delayed->class = c;
	297	bio_set_dev(bio, c->dev->bdev);
	298	if (bio_sectors(bio))
	299	bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
26b9f228	300
3876ac76	301	return delay_bio(dc, c, bio);
26b9f228 HM	302	}
26b9f228 HM	303
3876ac76 MP	304	#define DMEMIT_DELAY_CLASS(c) \
	305	DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
	306
fd7c092e MP	307	static void delay_status(struct dm_target *ti, status_type_t type,
fd7c092e MP	308	unsigned status_flags, char *result, unsigned maxlen)
26b9f228 HM	309	{
	310	struct delay_c *dc = ti->private;
	311	int sz = 0;
	312
	313	switch (type) {
	314	case STATUSTYPE_INFO:
cda6b5ab	315	DMEMIT("%u %u %u", dc->read.ops, dc->write.ops, dc->flush.ops);
26b9f228 HM	316	break;
	317
	318	case STATUSTYPE_TABLE:
3876ac76 MP	319	DMEMIT_DELAY_CLASS(&dc->read);
	320	if (dc->argc >= 6) {
	321	DMEMIT(" ");
	322	DMEMIT_DELAY_CLASS(&dc->write);
	323	}
cda6b5ab MP	324	if (dc->argc >= 9) {
	325	DMEMIT(" ");
	326	DMEMIT_DELAY_CLASS(&dc->flush);
	327	}
26b9f228 HM	328	break;
26b9f228 HM	329	}
26b9f228 HM	330	}
26b9f228 HM	331
af4874e0 MS	332	static int delay_iterate_devices(struct dm_target *ti,
	333	iterate_devices_callout_fn fn, void *data)
	334	{
	335	struct delay_c *dc = ti->private;
	336	int ret = 0;
	337
3876ac76 MP	338	ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data);
	339	if (ret)
	340	goto out;
	341	ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data);
af4874e0 MS	342	if (ret)
af4874e0 MS	343	goto out;
cda6b5ab MP	344	ret = fn(ti, dc->flush.dev, dc->flush.start, ti->len, data);
	345	if (ret)
	346	goto out;
af4874e0 MS	347
	348	out:
	349	return ret;
	350	}
	351
26b9f228 HM	352	static struct target_type delay_target = {
26b9f228 HM	353	.name = "delay",
fd7c092e	354	.version = {1, 2, 1},
e2460f2a	355	.features = DM_TARGET_PASSES_INTEGRITY,
26b9f228 HM	356	.module = THIS_MODULE,
	357	.ctr = delay_ctr,
	358	.dtr = delay_dtr,
	359	.map = delay_map,
	360	.presuspend = delay_presuspend,
	361	.resume = delay_resume,
	362	.status = delay_status,
af4874e0	363	.iterate_devices = delay_iterate_devices,
26b9f228 HM	364	};
	365
	366	static int __init dm_delay_init(void)
	367	{
42065460	368	int r;
26b9f228 HM	369
	370	r = dm_register_target(&delay_target);
	371	if (r < 0) {
	372	DMERR("register failed %d", r);
	373	goto bad_register;
	374	}
	375
	376	return 0;
	377
	378	bad_register:
26b9f228 HM	379	return r;
	380	}
	381
	382	static void __exit dm_delay_exit(void)
	383	{
10d3bd09	384	dm_unregister_target(&delay_target);
26b9f228 HM	385	}
	386
	387	/* Module hooks */
	388	module_init(dm_delay_init);
	389	module_exit(dm_delay_exit);
	390
	391	MODULE_DESCRIPTION(DM_NAME " delay target");
	392	MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
	393	MODULE_LICENSE("GPL");