Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2005-2007 Red Hat GmbH
4 *
5 * A target that delays reads and/or writes and can send
6 * them to different devices.
7 *
8 * This file is released under the GPL.
9 */
10
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/blkdev.h>
14#include <linux/bio.h>
15#include <linux/slab.h>
16#include <linux/kthread.h>
17
18#include <linux/device-mapper.h>
19
20#define DM_MSG_PREFIX "delay"
21
22struct delay_class {
23 struct dm_dev *dev;
24 sector_t start;
25 unsigned int delay;
26 unsigned int ops;
27};
28
29struct delay_c {
30 struct timer_list delay_timer;
31 struct mutex timer_lock;
32 struct workqueue_struct *kdelayd_wq;
33 struct work_struct flush_expired_bios;
34 struct list_head delayed_bios;
35 struct task_struct *worker;
36 bool may_delay;
37
38 struct delay_class read;
39 struct delay_class write;
40 struct delay_class flush;
41
42 int argc;
43};
44
45struct dm_delay_info {
46 struct delay_c *context;
47 struct delay_class *class;
48 struct list_head list;
49 unsigned long expires;
50};
51
52static DEFINE_MUTEX(delayed_bios_lock);
53
54static void handle_delayed_timer(struct timer_list *t)
55{
56 struct delay_c *dc = from_timer(dc, t, delay_timer);
57
58 queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
59}
60
61static void queue_timeout(struct delay_c *dc, unsigned long expires)
62{
63 mutex_lock(&dc->timer_lock);
64
65 if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
66 mod_timer(&dc->delay_timer, expires);
67
68 mutex_unlock(&dc->timer_lock);
69}
70
71static inline bool delay_is_fast(struct delay_c *dc)
72{
73 return !!dc->worker;
74}
75
76static void flush_bios(struct bio *bio)
77{
78 struct bio *n;
79
80 while (bio) {
81 n = bio->bi_next;
82 bio->bi_next = NULL;
83 dm_submit_bio_remap(bio, NULL);
84 bio = n;
85 }
86}
87
88static void flush_delayed_bios(struct delay_c *dc, bool flush_all)
89{
90 struct dm_delay_info *delayed, *next;
91 struct bio_list flush_bio_list;
92 unsigned long next_expires = 0;
93 bool start_timer = false;
94 bio_list_init(&flush_bio_list);
95
96 mutex_lock(&delayed_bios_lock);
97 list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
98 cond_resched();
99 if (flush_all || time_after_eq(jiffies, delayed->expires)) {
100 struct bio *bio = dm_bio_from_per_bio_data(delayed,
101 sizeof(struct dm_delay_info));
102 list_del(&delayed->list);
103 bio_list_add(&flush_bio_list, bio);
104 delayed->class->ops--;
105 continue;
106 }
107
108 if (!delay_is_fast(dc)) {
109 if (!start_timer) {
110 start_timer = true;
111 next_expires = delayed->expires;
112 } else {
113 next_expires = min(next_expires, delayed->expires);
114 }
115 }
116 }
117 mutex_unlock(&delayed_bios_lock);
118
119 if (start_timer)
120 queue_timeout(dc, next_expires);
121
122 flush_bios(bio_list_get(&flush_bio_list));
123}
124
125static int flush_worker_fn(void *data)
126{
127 struct delay_c *dc = data;
128
129 while (!kthread_should_stop()) {
130 flush_delayed_bios(dc, false);
131 mutex_lock(&delayed_bios_lock);
132 if (unlikely(list_empty(&dc->delayed_bios))) {
133 set_current_state(TASK_INTERRUPTIBLE);
134 mutex_unlock(&delayed_bios_lock);
135 schedule();
136 } else {
137 mutex_unlock(&delayed_bios_lock);
138 cond_resched();
139 }
140 }
141
142 return 0;
143}
144
145static void flush_expired_bios(struct work_struct *work)
146{
147 struct delay_c *dc;
148
149 dc = container_of(work, struct delay_c, flush_expired_bios);
150 flush_delayed_bios(dc, false);
151}
152
153static void delay_dtr(struct dm_target *ti)
154{
155 struct delay_c *dc = ti->private;
156
157 if (dc->kdelayd_wq)
158 destroy_workqueue(dc->kdelayd_wq);
159
160 if (dc->read.dev)
161 dm_put_device(ti, dc->read.dev);
162 if (dc->write.dev)
163 dm_put_device(ti, dc->write.dev);
164 if (dc->flush.dev)
165 dm_put_device(ti, dc->flush.dev);
166 if (dc->worker)
167 kthread_stop(dc->worker);
168
169 mutex_destroy(&dc->timer_lock);
170
171 kfree(dc);
172}
173
174static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **argv)
175{
176 int ret;
177 unsigned long long tmpll;
178 char dummy;
179
180 if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
181 ti->error = "Invalid device sector";
182 return -EINVAL;
183 }
184 c->start = tmpll;
185
186 if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) {
187 ti->error = "Invalid delay";
188 return -EINVAL;
189 }
190
191 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev);
192 if (ret) {
193 ti->error = "Device lookup failed";
194 return ret;
195 }
196
197 return 0;
198}
199
200/*
201 * Mapping parameters:
202 * <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
203 *
204 * With separate write parameters, the first set is only used for reads.
205 * Offsets are specified in sectors.
206 * Delays are specified in milliseconds.
207 */
208static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
209{
210 struct delay_c *dc;
211 int ret;
212 unsigned int max_delay;
213
214 if (argc != 3 && argc != 6 && argc != 9) {
215 ti->error = "Requires exactly 3, 6 or 9 arguments";
216 return -EINVAL;
217 }
218
219 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
220 if (!dc) {
221 ti->error = "Cannot allocate context";
222 return -ENOMEM;
223 }
224
225 ti->private = dc;
226 INIT_LIST_HEAD(&dc->delayed_bios);
227 mutex_init(&dc->timer_lock);
228 dc->may_delay = true;
229 dc->argc = argc;
230
231 ret = delay_class_ctr(ti, &dc->read, argv);
232 if (ret)
233 goto bad;
234 max_delay = dc->read.delay;
235
236 if (argc == 3) {
237 ret = delay_class_ctr(ti, &dc->write, argv);
238 if (ret)
239 goto bad;
240 ret = delay_class_ctr(ti, &dc->flush, argv);
241 if (ret)
242 goto bad;
243 max_delay = max(max_delay, dc->write.delay);
244 max_delay = max(max_delay, dc->flush.delay);
245 goto out;
246 }
247
248 ret = delay_class_ctr(ti, &dc->write, argv + 3);
249 if (ret)
250 goto bad;
251 if (argc == 6) {
252 ret = delay_class_ctr(ti, &dc->flush, argv + 3);
253 if (ret)
254 goto bad;
255 max_delay = max(max_delay, dc->flush.delay);
256 goto out;
257 }
258
259 ret = delay_class_ctr(ti, &dc->flush, argv + 6);
260 if (ret)
261 goto bad;
262 max_delay = max(max_delay, dc->flush.delay);
263
264out:
265 if (max_delay < 50) {
266 /*
267 * In case of small requested delays, use kthread instead of
268 * timers and workqueue to achieve better latency.
269 */
270 dc->worker = kthread_create(&flush_worker_fn, dc,
271 "dm-delay-flush-worker");
272 if (IS_ERR(dc->worker)) {
273 ret = PTR_ERR(dc->worker);
274 dc->worker = NULL;
275 goto bad;
276 }
277 } else {
278 timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
279 INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
280 dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
281 if (!dc->kdelayd_wq) {
282 ret = -EINVAL;
283 DMERR("Couldn't start kdelayd");
284 goto bad;
285 }
286 }
287
288 ti->num_flush_bios = 1;
289 ti->num_discard_bios = 1;
290 ti->accounts_remapped_io = true;
291 ti->per_io_data_size = sizeof(struct dm_delay_info);
292 return 0;
293
294bad:
295 delay_dtr(ti);
296 return ret;
297}
298
299static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
300{
301 struct dm_delay_info *delayed;
302 unsigned long expires = 0;
303
304 if (!c->delay)
305 return DM_MAPIO_REMAPPED;
306
307 delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
308
309 delayed->context = dc;
310 delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);
311
312 mutex_lock(&delayed_bios_lock);
313 if (unlikely(!dc->may_delay)) {
314 mutex_unlock(&delayed_bios_lock);
315 return DM_MAPIO_REMAPPED;
316 }
317 c->ops++;
318 list_add_tail(&delayed->list, &dc->delayed_bios);
319 mutex_unlock(&delayed_bios_lock);
320
321 if (delay_is_fast(dc))
322 wake_up_process(dc->worker);
323 else
324 queue_timeout(dc, expires);
325
326 return DM_MAPIO_SUBMITTED;
327}
328
329static void delay_presuspend(struct dm_target *ti)
330{
331 struct delay_c *dc = ti->private;
332
333 mutex_lock(&delayed_bios_lock);
334 dc->may_delay = false;
335 mutex_unlock(&delayed_bios_lock);
336
337 if (!delay_is_fast(dc))
338 del_timer_sync(&dc->delay_timer);
339 flush_delayed_bios(dc, true);
340}
341
342static void delay_resume(struct dm_target *ti)
343{
344 struct delay_c *dc = ti->private;
345
346 dc->may_delay = true;
347}
348
349static int delay_map(struct dm_target *ti, struct bio *bio)
350{
351 struct delay_c *dc = ti->private;
352 struct delay_class *c;
353 struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
354
355 if (bio_data_dir(bio) == WRITE) {
356 if (unlikely(bio->bi_opf & REQ_PREFLUSH))
357 c = &dc->flush;
358 else
359 c = &dc->write;
360 } else {
361 c = &dc->read;
362 }
363 delayed->class = c;
364 bio_set_dev(bio, c->dev->bdev);
365 bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
366
367 return delay_bio(dc, c, bio);
368}
369
370#define DMEMIT_DELAY_CLASS(c) \
371 DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
372
373static void delay_status(struct dm_target *ti, status_type_t type,
374 unsigned int status_flags, char *result, unsigned int maxlen)
375{
376 struct delay_c *dc = ti->private;
377 int sz = 0;
378
379 switch (type) {
380 case STATUSTYPE_INFO:
381 DMEMIT("%u %u %u", dc->read.ops, dc->write.ops, dc->flush.ops);
382 break;
383
384 case STATUSTYPE_TABLE:
385 DMEMIT_DELAY_CLASS(&dc->read);
386 if (dc->argc >= 6) {
387 DMEMIT(" ");
388 DMEMIT_DELAY_CLASS(&dc->write);
389 }
390 if (dc->argc >= 9) {
391 DMEMIT(" ");
392 DMEMIT_DELAY_CLASS(&dc->flush);
393 }
394 break;
395
396 case STATUSTYPE_IMA:
397 *result = '\0';
398 break;
399 }
400}
401
402static int delay_iterate_devices(struct dm_target *ti,
403 iterate_devices_callout_fn fn, void *data)
404{
405 struct delay_c *dc = ti->private;
406 int ret = 0;
407
408 ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data);
409 if (ret)
410 goto out;
411 ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data);
412 if (ret)
413 goto out;
414 ret = fn(ti, dc->flush.dev, dc->flush.start, ti->len, data);
415 if (ret)
416 goto out;
417
418out:
419 return ret;
420}
421
422static struct target_type delay_target = {
423 .name = "delay",
424 .version = {1, 4, 0},
425 .features = DM_TARGET_PASSES_INTEGRITY,
426 .module = THIS_MODULE,
427 .ctr = delay_ctr,
428 .dtr = delay_dtr,
429 .map = delay_map,
430 .presuspend = delay_presuspend,
431 .resume = delay_resume,
432 .status = delay_status,
433 .iterate_devices = delay_iterate_devices,
434};
435module_dm(delay);
436
437MODULE_DESCRIPTION(DM_NAME " delay target");
438MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
439MODULE_LICENSE("GPL");
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
16#include <linux/device-mapper.h>
17
18#define DM_MSG_PREFIX "delay"
19
20struct delay_class {
21 struct dm_dev *dev;
22 sector_t start;
23 unsigned delay;
24 unsigned ops;
25};
26
27struct delay_c {
28 struct timer_list delay_timer;
29 struct mutex timer_lock;
30 struct workqueue_struct *kdelayd_wq;
31 struct work_struct flush_expired_bios;
32 struct list_head delayed_bios;
33 atomic_t may_delay;
34
35 struct delay_class read;
36 struct delay_class write;
37 struct delay_class flush;
38
39 int argc;
40};
41
42struct dm_delay_info {
43 struct delay_c *context;
44 struct delay_class *class;
45 struct list_head list;
46 unsigned long expires;
47};
48
49static DEFINE_MUTEX(delayed_bios_lock);
50
51static void handle_delayed_timer(struct timer_list *t)
52{
53 struct delay_c *dc = from_timer(dc, t, delay_timer);
54
55 queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
56}
57
58static void queue_timeout(struct delay_c *dc, unsigned long expires)
59{
60 mutex_lock(&dc->timer_lock);
61
62 if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
63 mod_timer(&dc->delay_timer, expires);
64
65 mutex_unlock(&dc->timer_lock);
66}
67
68static 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 submit_bio_noacct(bio);
76 bio = n;
77 }
78}
79
80static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
81{
82 struct dm_delay_info *delayed, *next;
83 unsigned long next_expires = 0;
84 unsigned long start_timer = 0;
85 struct bio_list flush_bios = { };
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)) {
90 struct bio *bio = dm_bio_from_per_bio_data(delayed,
91 sizeof(struct dm_delay_info));
92 list_del(&delayed->list);
93 bio_list_add(&flush_bios, bio);
94 delayed->class->ops--;
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 }
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
112static 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
120static void delay_dtr(struct dm_target *ti)
121{
122 struct delay_c *dc = ti->private;
123
124 if (dc->kdelayd_wq)
125 destroy_workqueue(dc->kdelayd_wq);
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);
131 if (dc->flush.dev)
132 dm_put_device(ti, dc->flush.dev);
133
134 mutex_destroy(&dc->timer_lock);
135
136 kfree(dc);
137}
138
139static 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
145 if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
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
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.
170 * Offsets are specified in sectors.
171 * Delays are specified in milliseconds.
172 */
173static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
174{
175 struct delay_c *dc;
176 int ret;
177
178 if (argc != 3 && argc != 6 && argc != 9) {
179 ti->error = "Requires exactly 3, 6 or 9 arguments";
180 return -EINVAL;
181 }
182
183 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
184 if (!dc) {
185 ti->error = "Cannot allocate context";
186 return -ENOMEM;
187 }
188
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;
196
197 ret = delay_class_ctr(ti, &dc->read, argv);
198 if (ret)
199 goto bad;
200
201 if (argc == 3) {
202 ret = delay_class_ctr(ti, &dc->write, argv);
203 if (ret)
204 goto bad;
205 ret = delay_class_ctr(ti, &dc->flush, argv);
206 if (ret)
207 goto bad;
208 goto out;
209 }
210
211 ret = delay_class_ctr(ti, &dc->write, argv + 3);
212 if (ret)
213 goto bad;
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;
224
225out:
226 dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
227 if (!dc->kdelayd_wq) {
228 ret = -EINVAL;
229 DMERR("Couldn't start kdelayd");
230 goto bad;
231 }
232
233 ti->num_flush_bios = 1;
234 ti->num_discard_bios = 1;
235 ti->per_io_data_size = sizeof(struct dm_delay_info);
236 return 0;
237
238bad:
239 delay_dtr(ti);
240 return ret;
241}
242
243static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
244{
245 struct dm_delay_info *delayed;
246 unsigned long expires = 0;
247
248 if (!c->delay || !atomic_read(&dc->may_delay))
249 return DM_MAPIO_REMAPPED;
250
251 delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
252
253 delayed->context = dc;
254 delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);
255
256 mutex_lock(&delayed_bios_lock);
257 c->ops++;
258 list_add_tail(&delayed->list, &dc->delayed_bios);
259 mutex_unlock(&delayed_bios_lock);
260
261 queue_timeout(dc, expires);
262
263 return DM_MAPIO_SUBMITTED;
264}
265
266static 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
275static 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
282static int delay_map(struct dm_target *ti, struct bio *bio)
283{
284 struct delay_c *dc = ti->private;
285 struct delay_class *c;
286 struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
287
288 if (bio_data_dir(bio) == WRITE) {
289 if (unlikely(bio->bi_opf & REQ_PREFLUSH))
290 c = &dc->flush;
291 else
292 c = &dc->write;
293 } else {
294 c = &dc->read;
295 }
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);
300
301 return delay_bio(dc, c, bio);
302}
303
304#define DMEMIT_DELAY_CLASS(c) \
305 DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
306
307static void delay_status(struct dm_target *ti, status_type_t type,
308 unsigned status_flags, char *result, unsigned maxlen)
309{
310 struct delay_c *dc = ti->private;
311 int sz = 0;
312
313 switch (type) {
314 case STATUSTYPE_INFO:
315 DMEMIT("%u %u %u", dc->read.ops, dc->write.ops, dc->flush.ops);
316 break;
317
318 case STATUSTYPE_TABLE:
319 DMEMIT_DELAY_CLASS(&dc->read);
320 if (dc->argc >= 6) {
321 DMEMIT(" ");
322 DMEMIT_DELAY_CLASS(&dc->write);
323 }
324 if (dc->argc >= 9) {
325 DMEMIT(" ");
326 DMEMIT_DELAY_CLASS(&dc->flush);
327 }
328 break;
329 }
330}
331
332static 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
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);
342 if (ret)
343 goto out;
344 ret = fn(ti, dc->flush.dev, dc->flush.start, ti->len, data);
345 if (ret)
346 goto out;
347
348out:
349 return ret;
350}
351
352static struct target_type delay_target = {
353 .name = "delay",
354 .version = {1, 2, 1},
355 .features = DM_TARGET_PASSES_INTEGRITY,
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,
363 .iterate_devices = delay_iterate_devices,
364};
365
366static int __init dm_delay_init(void)
367{
368 int r;
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
378bad_register:
379 return r;
380}
381
382static void __exit dm_delay_exit(void)
383{
384 dm_unregister_target(&delay_target);
385}
386
387/* Module hooks */
388module_init(dm_delay_init);
389module_exit(dm_delay_exit);
390
391MODULE_DESCRIPTION(DM_NAME " delay target");
392MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
393MODULE_LICENSE("GPL");