Merge remote-tracking branch 'asoc/fix/wm8993' into asoc-linus
[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / md / dm-delay.c
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
20 struct delay_c {
21         struct timer_list delay_timer;
22         struct mutex timer_lock;
23         struct workqueue_struct *kdelayd_wq;
24         struct work_struct flush_expired_bios;
25         struct list_head delayed_bios;
26         atomic_t may_delay;
27
28         struct dm_dev *dev_read;
29         sector_t start_read;
30         unsigned read_delay;
31         unsigned reads;
32
33         struct dm_dev *dev_write;
34         sector_t start_write;
35         unsigned write_delay;
36         unsigned writes;
37 };
38
39 struct dm_delay_info {
40         struct delay_c *context;
41         struct list_head list;
42         unsigned long expires;
43 };
44
45 static DEFINE_MUTEX(delayed_bios_lock);
46
47 static void handle_delayed_timer(unsigned long data)
48 {
49         struct delay_c *dc = (struct delay_c *)data;
50
51         queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
52 }
53
54 static void queue_timeout(struct delay_c *dc, unsigned long expires)
55 {
56         mutex_lock(&dc->timer_lock);
57
58         if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
59                 mod_timer(&dc->delay_timer, expires);
60
61         mutex_unlock(&dc->timer_lock);
62 }
63
64 static void flush_bios(struct bio *bio)
65 {
66         struct bio *n;
67
68         while (bio) {
69                 n = bio->bi_next;
70                 bio->bi_next = NULL;
71                 generic_make_request(bio);
72                 bio = n;
73         }
74 }
75
76 static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
77 {
78         struct dm_delay_info *delayed, *next;
79         unsigned long next_expires = 0;
80         int start_timer = 0;
81         struct bio_list flush_bios = { };
82
83         mutex_lock(&delayed_bios_lock);
84         list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
85                 if (flush_all || time_after_eq(jiffies, delayed->expires)) {
86                         struct bio *bio = dm_bio_from_per_bio_data(delayed,
87                                                 sizeof(struct dm_delay_info));
88                         list_del(&delayed->list);
89                         bio_list_add(&flush_bios, bio);
90                         if ((bio_data_dir(bio) == WRITE))
91                                 delayed->context->writes--;
92                         else
93                                 delayed->context->reads--;
94                         continue;
95                 }
96
97                 if (!start_timer) {
98                         start_timer = 1;
99                         next_expires = delayed->expires;
100                 } else
101                         next_expires = min(next_expires, delayed->expires);
102         }
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
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
120 /*
121  * Mapping parameters:
122  *    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
123  *
124  * With separate write parameters, the first set is only used for reads.
125  * Delays are specified in milliseconds.
126  */
127 static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
128 {
129         struct delay_c *dc;
130         unsigned long long tmpll;
131         char dummy;
132
133         if (argc != 3 && argc != 6) {
134                 ti->error = "requires exactly 3 or 6 arguments";
135                 return -EINVAL;
136         }
137
138         dc = kmalloc(sizeof(*dc), GFP_KERNEL);
139         if (!dc) {
140                 ti->error = "Cannot allocate context";
141                 return -ENOMEM;
142         }
143
144         dc->reads = dc->writes = 0;
145
146         if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
147                 ti->error = "Invalid device sector";
148                 goto bad;
149         }
150         dc->start_read = tmpll;
151
152         if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
153                 ti->error = "Invalid delay";
154                 goto bad;
155         }
156
157         if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
158                           &dc->dev_read)) {
159                 ti->error = "Device lookup failed";
160                 goto bad;
161         }
162
163         dc->dev_write = NULL;
164         if (argc == 3)
165                 goto out;
166
167         if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
168                 ti->error = "Invalid write device sector";
169                 goto bad_dev_read;
170         }
171         dc->start_write = tmpll;
172
173         if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
174                 ti->error = "Invalid write delay";
175                 goto bad_dev_read;
176         }
177
178         if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
179                           &dc->dev_write)) {
180                 ti->error = "Write device lookup failed";
181                 goto bad_dev_read;
182         }
183
184 out:
185         dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
186         if (!dc->kdelayd_wq) {
187                 DMERR("Couldn't start kdelayd");
188                 goto bad_queue;
189         }
190
191         setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc);
192
193         INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
194         INIT_LIST_HEAD(&dc->delayed_bios);
195         mutex_init(&dc->timer_lock);
196         atomic_set(&dc->may_delay, 1);
197
198         ti->num_flush_bios = 1;
199         ti->num_discard_bios = 1;
200         ti->per_bio_data_size = sizeof(struct dm_delay_info);
201         ti->private = dc;
202         return 0;
203
204 bad_queue:
205         if (dc->dev_write)
206                 dm_put_device(ti, dc->dev_write);
207 bad_dev_read:
208         dm_put_device(ti, dc->dev_read);
209 bad:
210         kfree(dc);
211         return -EINVAL;
212 }
213
214 static void delay_dtr(struct dm_target *ti)
215 {
216         struct delay_c *dc = ti->private;
217
218         destroy_workqueue(dc->kdelayd_wq);
219
220         dm_put_device(ti, dc->dev_read);
221
222         if (dc->dev_write)
223                 dm_put_device(ti, dc->dev_write);
224
225         kfree(dc);
226 }
227
228 static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
229 {
230         struct dm_delay_info *delayed;
231         unsigned long expires = 0;
232
233         if (!delay || !atomic_read(&dc->may_delay))
234                 return 1;
235
236         delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
237
238         delayed->context = dc;
239         delayed->expires = expires = jiffies + (delay * HZ / 1000);
240
241         mutex_lock(&delayed_bios_lock);
242
243         if (bio_data_dir(bio) == WRITE)
244                 dc->writes++;
245         else
246                 dc->reads++;
247
248         list_add_tail(&delayed->list, &dc->delayed_bios);
249
250         mutex_unlock(&delayed_bios_lock);
251
252         queue_timeout(dc, expires);
253
254         return 0;
255 }
256
257 static void delay_presuspend(struct dm_target *ti)
258 {
259         struct delay_c *dc = ti->private;
260
261         atomic_set(&dc->may_delay, 0);
262         del_timer_sync(&dc->delay_timer);
263         flush_bios(flush_delayed_bios(dc, 1));
264 }
265
266 static void delay_resume(struct dm_target *ti)
267 {
268         struct delay_c *dc = ti->private;
269
270         atomic_set(&dc->may_delay, 1);
271 }
272
273 static int delay_map(struct dm_target *ti, struct bio *bio)
274 {
275         struct delay_c *dc = ti->private;
276
277         if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) {
278                 bio->bi_bdev = dc->dev_write->bdev;
279                 if (bio_sectors(bio))
280                         bio->bi_iter.bi_sector = dc->start_write +
281                                 dm_target_offset(ti, bio->bi_iter.bi_sector);
282
283                 return delay_bio(dc, dc->write_delay, bio);
284         }
285
286         bio->bi_bdev = dc->dev_read->bdev;
287         bio->bi_iter.bi_sector = dc->start_read +
288                 dm_target_offset(ti, bio->bi_iter.bi_sector);
289
290         return delay_bio(dc, dc->read_delay, bio);
291 }
292
293 static void delay_status(struct dm_target *ti, status_type_t type,
294                          unsigned status_flags, char *result, unsigned maxlen)
295 {
296         struct delay_c *dc = ti->private;
297         int sz = 0;
298
299         switch (type) {
300         case STATUSTYPE_INFO:
301                 DMEMIT("%u %u", dc->reads, dc->writes);
302                 break;
303
304         case STATUSTYPE_TABLE:
305                 DMEMIT("%s %llu %u", dc->dev_read->name,
306                        (unsigned long long) dc->start_read,
307                        dc->read_delay);
308                 if (dc->dev_write)
309                         DMEMIT(" %s %llu %u", dc->dev_write->name,
310                                (unsigned long long) dc->start_write,
311                                dc->write_delay);
312                 break;
313         }
314 }
315
316 static int delay_iterate_devices(struct dm_target *ti,
317                                  iterate_devices_callout_fn fn, void *data)
318 {
319         struct delay_c *dc = ti->private;
320         int ret = 0;
321
322         ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data);
323         if (ret)
324                 goto out;
325
326         if (dc->dev_write)
327                 ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
328
329 out:
330         return ret;
331 }
332
333 static struct target_type delay_target = {
334         .name        = "delay",
335         .version     = {1, 2, 1},
336         .module      = THIS_MODULE,
337         .ctr         = delay_ctr,
338         .dtr         = delay_dtr,
339         .map         = delay_map,
340         .presuspend  = delay_presuspend,
341         .resume      = delay_resume,
342         .status      = delay_status,
343         .iterate_devices = delay_iterate_devices,
344 };
345
346 static int __init dm_delay_init(void)
347 {
348         int r;
349
350         r = dm_register_target(&delay_target);
351         if (r < 0) {
352                 DMERR("register failed %d", r);
353                 goto bad_register;
354         }
355
356         return 0;
357
358 bad_register:
359         return r;
360 }
361
362 static void __exit dm_delay_exit(void)
363 {
364         dm_unregister_target(&delay_target);
365 }
366
367 /* Module hooks */
368 module_init(dm_delay_init);
369 module_exit(dm_delay_exit);
370
371 MODULE_DESCRIPTION(DM_NAME " delay target");
372 MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");
373 MODULE_LICENSE("GPL");