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1/*
2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm.h"
8#include <linux/device-mapper.h>
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#include <linux/log2.h>
16
17#define DM_MSG_PREFIX "striped"
18#define DM_IO_ERROR_THRESHOLD 15
19
20struct stripe {
21 struct dm_dev *dev;
22 sector_t physical_start;
23
24 atomic_t error_count;
25};
26
27struct stripe_c {
28 uint32_t stripes;
29 int stripes_shift;
30
31 /* The size of this target / num. stripes */
32 sector_t stripe_width;
33
34 uint32_t chunk_size;
35 int chunk_size_shift;
36
37 /* Needed for handling events */
38 struct dm_target *ti;
39
40 /* Work struct used for triggering events*/
41 struct work_struct trigger_event;
42
43 struct stripe stripe[0];
44};
45
46/*
47 * An event is triggered whenever a drive
48 * drops out of a stripe volume.
49 */
50static void trigger_event(struct work_struct *work)
51{
52 struct stripe_c *sc = container_of(work, struct stripe_c,
53 trigger_event);
54 dm_table_event(sc->ti->table);
55}
56
57static inline struct stripe_c *alloc_context(unsigned int stripes)
58{
59 size_t len;
60
61 if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
62 stripes))
63 return NULL;
64
65 len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
66
67 return kmalloc(len, GFP_KERNEL);
68}
69
70/*
71 * Parse a single <dev> <sector> pair
72 */
73static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
74 unsigned int stripe, char **argv)
75{
76 unsigned long long start;
77 char dummy;
78 int ret;
79
80 if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
81 return -EINVAL;
82
83 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
84 &sc->stripe[stripe].dev);
85 if (ret)
86 return ret;
87
88 sc->stripe[stripe].physical_start = start;
89
90 return 0;
91}
92
93/*
94 * Construct a striped mapping.
95 * <number of stripes> <chunk size> [<dev_path> <offset>]+
96 */
97static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
98{
99 struct stripe_c *sc;
100 sector_t width, tmp_len;
101 uint32_t stripes;
102 uint32_t chunk_size;
103 int r;
104 unsigned int i;
105
106 if (argc < 2) {
107 ti->error = "Not enough arguments";
108 return -EINVAL;
109 }
110
111 if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
112 ti->error = "Invalid stripe count";
113 return -EINVAL;
114 }
115
116 if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
117 ti->error = "Invalid chunk_size";
118 return -EINVAL;
119 }
120
121 width = ti->len;
122 if (sector_div(width, stripes)) {
123 ti->error = "Target length not divisible by "
124 "number of stripes";
125 return -EINVAL;
126 }
127
128 tmp_len = width;
129 if (sector_div(tmp_len, chunk_size)) {
130 ti->error = "Target length not divisible by "
131 "chunk size";
132 return -EINVAL;
133 }
134
135 /*
136 * Do we have enough arguments for that many stripes ?
137 */
138 if (argc != (2 + 2 * stripes)) {
139 ti->error = "Not enough destinations "
140 "specified";
141 return -EINVAL;
142 }
143
144 sc = alloc_context(stripes);
145 if (!sc) {
146 ti->error = "Memory allocation for striped context "
147 "failed";
148 return -ENOMEM;
149 }
150
151 INIT_WORK(&sc->trigger_event, trigger_event);
152
153 /* Set pointer to dm target; used in trigger_event */
154 sc->ti = ti;
155 sc->stripes = stripes;
156 sc->stripe_width = width;
157
158 if (stripes & (stripes - 1))
159 sc->stripes_shift = -1;
160 else
161 sc->stripes_shift = __ffs(stripes);
162
163 r = dm_set_target_max_io_len(ti, chunk_size);
164 if (r) {
165 kfree(sc);
166 return r;
167 }
168
169 ti->num_flush_bios = stripes;
170 ti->num_discard_bios = stripes;
171 ti->num_write_same_bios = stripes;
172
173 sc->chunk_size = chunk_size;
174 if (chunk_size & (chunk_size - 1))
175 sc->chunk_size_shift = -1;
176 else
177 sc->chunk_size_shift = __ffs(chunk_size);
178
179 /*
180 * Get the stripe destinations.
181 */
182 for (i = 0; i < stripes; i++) {
183 argv += 2;
184
185 r = get_stripe(ti, sc, i, argv);
186 if (r < 0) {
187 ti->error = "Couldn't parse stripe destination";
188 while (i--)
189 dm_put_device(ti, sc->stripe[i].dev);
190 kfree(sc);
191 return r;
192 }
193 atomic_set(&(sc->stripe[i].error_count), 0);
194 }
195
196 ti->private = sc;
197
198 return 0;
199}
200
201static void stripe_dtr(struct dm_target *ti)
202{
203 unsigned int i;
204 struct stripe_c *sc = (struct stripe_c *) ti->private;
205
206 for (i = 0; i < sc->stripes; i++)
207 dm_put_device(ti, sc->stripe[i].dev);
208
209 flush_work(&sc->trigger_event);
210 kfree(sc);
211}
212
213static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
214 uint32_t *stripe, sector_t *result)
215{
216 sector_t chunk = dm_target_offset(sc->ti, sector);
217 sector_t chunk_offset;
218
219 if (sc->chunk_size_shift < 0)
220 chunk_offset = sector_div(chunk, sc->chunk_size);
221 else {
222 chunk_offset = chunk & (sc->chunk_size - 1);
223 chunk >>= sc->chunk_size_shift;
224 }
225
226 if (sc->stripes_shift < 0)
227 *stripe = sector_div(chunk, sc->stripes);
228 else {
229 *stripe = chunk & (sc->stripes - 1);
230 chunk >>= sc->stripes_shift;
231 }
232
233 if (sc->chunk_size_shift < 0)
234 chunk *= sc->chunk_size;
235 else
236 chunk <<= sc->chunk_size_shift;
237
238 *result = chunk + chunk_offset;
239}
240
241static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
242 uint32_t target_stripe, sector_t *result)
243{
244 uint32_t stripe;
245
246 stripe_map_sector(sc, sector, &stripe, result);
247 if (stripe == target_stripe)
248 return;
249
250 /* round down */
251 sector = *result;
252 if (sc->chunk_size_shift < 0)
253 *result -= sector_div(sector, sc->chunk_size);
254 else
255 *result = sector & ~(sector_t)(sc->chunk_size - 1);
256
257 if (target_stripe < stripe)
258 *result += sc->chunk_size; /* next chunk */
259}
260
261static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
262 uint32_t target_stripe)
263{
264 sector_t begin, end;
265
266 stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
267 target_stripe, &begin);
268 stripe_map_range_sector(sc, bio_end_sector(bio),
269 target_stripe, &end);
270 if (begin < end) {
271 bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
272 bio->bi_iter.bi_sector = begin +
273 sc->stripe[target_stripe].physical_start;
274 bio->bi_iter.bi_size = to_bytes(end - begin);
275 return DM_MAPIO_REMAPPED;
276 } else {
277 /* The range doesn't map to the target stripe */
278 bio_endio(bio);
279 return DM_MAPIO_SUBMITTED;
280 }
281}
282
283static int stripe_map(struct dm_target *ti, struct bio *bio)
284{
285 struct stripe_c *sc = ti->private;
286 uint32_t stripe;
287 unsigned target_bio_nr;
288
289 if (bio->bi_rw & REQ_FLUSH) {
290 target_bio_nr = dm_bio_get_target_bio_nr(bio);
291 BUG_ON(target_bio_nr >= sc->stripes);
292 bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
293 return DM_MAPIO_REMAPPED;
294 }
295 if (unlikely(bio->bi_rw & REQ_DISCARD) ||
296 unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
297 target_bio_nr = dm_bio_get_target_bio_nr(bio);
298 BUG_ON(target_bio_nr >= sc->stripes);
299 return stripe_map_range(sc, bio, target_bio_nr);
300 }
301
302 stripe_map_sector(sc, bio->bi_iter.bi_sector,
303 &stripe, &bio->bi_iter.bi_sector);
304
305 bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
306 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
307
308 return DM_MAPIO_REMAPPED;
309}
310
311/*
312 * Stripe status:
313 *
314 * INFO
315 * #stripes [stripe_name <stripe_name>] [group word count]
316 * [error count 'A|D' <error count 'A|D'>]
317 *
318 * TABLE
319 * #stripes [stripe chunk size]
320 * [stripe_name physical_start <stripe_name physical_start>]
321 *
322 */
323
324static void stripe_status(struct dm_target *ti, status_type_t type,
325 unsigned status_flags, char *result, unsigned maxlen)
326{
327 struct stripe_c *sc = (struct stripe_c *) ti->private;
328 char buffer[sc->stripes + 1];
329 unsigned int sz = 0;
330 unsigned int i;
331
332 switch (type) {
333 case STATUSTYPE_INFO:
334 DMEMIT("%d ", sc->stripes);
335 for (i = 0; i < sc->stripes; i++) {
336 DMEMIT("%s ", sc->stripe[i].dev->name);
337 buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
338 'D' : 'A';
339 }
340 buffer[i] = '\0';
341 DMEMIT("1 %s", buffer);
342 break;
343
344 case STATUSTYPE_TABLE:
345 DMEMIT("%d %llu", sc->stripes,
346 (unsigned long long)sc->chunk_size);
347 for (i = 0; i < sc->stripes; i++)
348 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
349 (unsigned long long)sc->stripe[i].physical_start);
350 break;
351 }
352}
353
354static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
355{
356 unsigned i;
357 char major_minor[16];
358 struct stripe_c *sc = ti->private;
359
360 if (!error)
361 return 0; /* I/O complete */
362
363 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
364 return error;
365
366 if (error == -EOPNOTSUPP)
367 return error;
368
369 memset(major_minor, 0, sizeof(major_minor));
370 sprintf(major_minor, "%d:%d",
371 MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
372 MINOR(disk_devt(bio->bi_bdev->bd_disk)));
373
374 /*
375 * Test to see which stripe drive triggered the event
376 * and increment error count for all stripes on that device.
377 * If the error count for a given device exceeds the threshold
378 * value we will no longer trigger any further events.
379 */
380 for (i = 0; i < sc->stripes; i++)
381 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
382 atomic_inc(&(sc->stripe[i].error_count));
383 if (atomic_read(&(sc->stripe[i].error_count)) <
384 DM_IO_ERROR_THRESHOLD)
385 schedule_work(&sc->trigger_event);
386 }
387
388 return error;
389}
390
391static int stripe_iterate_devices(struct dm_target *ti,
392 iterate_devices_callout_fn fn, void *data)
393{
394 struct stripe_c *sc = ti->private;
395 int ret = 0;
396 unsigned i = 0;
397
398 do {
399 ret = fn(ti, sc->stripe[i].dev,
400 sc->stripe[i].physical_start,
401 sc->stripe_width, data);
402 } while (!ret && ++i < sc->stripes);
403
404 return ret;
405}
406
407static void stripe_io_hints(struct dm_target *ti,
408 struct queue_limits *limits)
409{
410 struct stripe_c *sc = ti->private;
411 unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
412
413 blk_limits_io_min(limits, chunk_size);
414 blk_limits_io_opt(limits, chunk_size * sc->stripes);
415}
416
417static struct target_type stripe_target = {
418 .name = "striped",
419 .version = {1, 5, 1},
420 .module = THIS_MODULE,
421 .ctr = stripe_ctr,
422 .dtr = stripe_dtr,
423 .map = stripe_map,
424 .end_io = stripe_end_io,
425 .status = stripe_status,
426 .iterate_devices = stripe_iterate_devices,
427 .io_hints = stripe_io_hints,
428};
429
430int __init dm_stripe_init(void)
431{
432 int r;
433
434 r = dm_register_target(&stripe_target);
435 if (r < 0)
436 DMWARN("target registration failed");
437
438 return r;
439}
440
441void dm_stripe_exit(void)
442{
443 dm_unregister_target(&stripe_target);
444}
1/*
2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
3 *
4 * This file is released under the GPL.
5 */
6
7#include <linux/device-mapper.h>
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>
14#include <linux/log2.h>
15
16#define DM_MSG_PREFIX "striped"
17#define DM_IO_ERROR_THRESHOLD 15
18
19struct stripe {
20 struct dm_dev *dev;
21 sector_t physical_start;
22
23 atomic_t error_count;
24};
25
26struct stripe_c {
27 uint32_t stripes;
28 int stripes_shift;
29 sector_t stripes_mask;
30
31 /* The size of this target / num. stripes */
32 sector_t stripe_width;
33
34 /* stripe chunk size */
35 uint32_t chunk_shift;
36 sector_t chunk_mask;
37
38 /* Needed for handling events */
39 struct dm_target *ti;
40
41 /* Work struct used for triggering events*/
42 struct work_struct trigger_event;
43
44 struct stripe stripe[0];
45};
46
47/*
48 * An event is triggered whenever a drive
49 * drops out of a stripe volume.
50 */
51static void trigger_event(struct work_struct *work)
52{
53 struct stripe_c *sc = container_of(work, struct stripe_c,
54 trigger_event);
55 dm_table_event(sc->ti->table);
56}
57
58static inline struct stripe_c *alloc_context(unsigned int stripes)
59{
60 size_t len;
61
62 if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
63 stripes))
64 return NULL;
65
66 len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
67
68 return kmalloc(len, GFP_KERNEL);
69}
70
71/*
72 * Parse a single <dev> <sector> pair
73 */
74static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
75 unsigned int stripe, char **argv)
76{
77 unsigned long long start;
78
79 if (sscanf(argv[1], "%llu", &start) != 1)
80 return -EINVAL;
81
82 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
83 &sc->stripe[stripe].dev))
84 return -ENXIO;
85
86 sc->stripe[stripe].physical_start = start;
87
88 return 0;
89}
90
91/*
92 * Construct a striped mapping.
93 * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
94 */
95static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
96{
97 struct stripe_c *sc;
98 sector_t width;
99 uint32_t stripes;
100 uint32_t chunk_size;
101 char *end;
102 int r;
103 unsigned int i;
104
105 if (argc < 2) {
106 ti->error = "Not enough arguments";
107 return -EINVAL;
108 }
109
110 stripes = simple_strtoul(argv[0], &end, 10);
111 if (!stripes || *end) {
112 ti->error = "Invalid stripe count";
113 return -EINVAL;
114 }
115
116 chunk_size = simple_strtoul(argv[1], &end, 10);
117 if (*end) {
118 ti->error = "Invalid chunk_size";
119 return -EINVAL;
120 }
121
122 /*
123 * chunk_size is a power of two
124 */
125 if (!is_power_of_2(chunk_size) ||
126 (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
127 ti->error = "Invalid chunk size";
128 return -EINVAL;
129 }
130
131 if (ti->len & (chunk_size - 1)) {
132 ti->error = "Target length not divisible by "
133 "chunk size";
134 return -EINVAL;
135 }
136
137 width = ti->len;
138 if (sector_div(width, stripes)) {
139 ti->error = "Target length not divisible by "
140 "number of stripes";
141 return -EINVAL;
142 }
143
144 /*
145 * Do we have enough arguments for that many stripes ?
146 */
147 if (argc != (2 + 2 * stripes)) {
148 ti->error = "Not enough destinations "
149 "specified";
150 return -EINVAL;
151 }
152
153 sc = alloc_context(stripes);
154 if (!sc) {
155 ti->error = "Memory allocation for striped context "
156 "failed";
157 return -ENOMEM;
158 }
159
160 INIT_WORK(&sc->trigger_event, trigger_event);
161
162 /* Set pointer to dm target; used in trigger_event */
163 sc->ti = ti;
164 sc->stripes = stripes;
165 sc->stripe_width = width;
166
167 if (stripes & (stripes - 1))
168 sc->stripes_shift = -1;
169 else {
170 sc->stripes_shift = ffs(stripes) - 1;
171 sc->stripes_mask = ((sector_t) stripes) - 1;
172 }
173
174 ti->split_io = chunk_size;
175 ti->num_flush_requests = stripes;
176 ti->num_discard_requests = stripes;
177
178 sc->chunk_shift = ffs(chunk_size) - 1;
179 sc->chunk_mask = ((sector_t) chunk_size) - 1;
180
181 /*
182 * Get the stripe destinations.
183 */
184 for (i = 0; i < stripes; i++) {
185 argv += 2;
186
187 r = get_stripe(ti, sc, i, argv);
188 if (r < 0) {
189 ti->error = "Couldn't parse stripe destination";
190 while (i--)
191 dm_put_device(ti, sc->stripe[i].dev);
192 kfree(sc);
193 return r;
194 }
195 atomic_set(&(sc->stripe[i].error_count), 0);
196 }
197
198 ti->private = sc;
199
200 return 0;
201}
202
203static void stripe_dtr(struct dm_target *ti)
204{
205 unsigned int i;
206 struct stripe_c *sc = (struct stripe_c *) ti->private;
207
208 for (i = 0; i < sc->stripes; i++)
209 dm_put_device(ti, sc->stripe[i].dev);
210
211 flush_work_sync(&sc->trigger_event);
212 kfree(sc);
213}
214
215static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
216 uint32_t *stripe, sector_t *result)
217{
218 sector_t offset = dm_target_offset(sc->ti, sector);
219 sector_t chunk = offset >> sc->chunk_shift;
220
221 if (sc->stripes_shift < 0)
222 *stripe = sector_div(chunk, sc->stripes);
223 else {
224 *stripe = chunk & sc->stripes_mask;
225 chunk >>= sc->stripes_shift;
226 }
227
228 *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask);
229}
230
231static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
232 uint32_t target_stripe, sector_t *result)
233{
234 uint32_t stripe;
235
236 stripe_map_sector(sc, sector, &stripe, result);
237 if (stripe == target_stripe)
238 return;
239 *result &= ~sc->chunk_mask; /* round down */
240 if (target_stripe < stripe)
241 *result += sc->chunk_mask + 1; /* next chunk */
242}
243
244static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
245 uint32_t target_stripe)
246{
247 sector_t begin, end;
248
249 stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
250 stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
251 target_stripe, &end);
252 if (begin < end) {
253 bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
254 bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
255 bio->bi_size = to_bytes(end - begin);
256 return DM_MAPIO_REMAPPED;
257 } else {
258 /* The range doesn't map to the target stripe */
259 bio_endio(bio, 0);
260 return DM_MAPIO_SUBMITTED;
261 }
262}
263
264static int stripe_map(struct dm_target *ti, struct bio *bio,
265 union map_info *map_context)
266{
267 struct stripe_c *sc = ti->private;
268 uint32_t stripe;
269 unsigned target_request_nr;
270
271 if (bio->bi_rw & REQ_FLUSH) {
272 target_request_nr = map_context->target_request_nr;
273 BUG_ON(target_request_nr >= sc->stripes);
274 bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
275 return DM_MAPIO_REMAPPED;
276 }
277 if (unlikely(bio->bi_rw & REQ_DISCARD)) {
278 target_request_nr = map_context->target_request_nr;
279 BUG_ON(target_request_nr >= sc->stripes);
280 return stripe_map_discard(sc, bio, target_request_nr);
281 }
282
283 stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
284
285 bio->bi_sector += sc->stripe[stripe].physical_start;
286 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
287
288 return DM_MAPIO_REMAPPED;
289}
290
291/*
292 * Stripe status:
293 *
294 * INFO
295 * #stripes [stripe_name <stripe_name>] [group word count]
296 * [error count 'A|D' <error count 'A|D'>]
297 *
298 * TABLE
299 * #stripes [stripe chunk size]
300 * [stripe_name physical_start <stripe_name physical_start>]
301 *
302 */
303
304static int stripe_status(struct dm_target *ti,
305 status_type_t type, char *result, unsigned int maxlen)
306{
307 struct stripe_c *sc = (struct stripe_c *) ti->private;
308 char buffer[sc->stripes + 1];
309 unsigned int sz = 0;
310 unsigned int i;
311
312 switch (type) {
313 case STATUSTYPE_INFO:
314 DMEMIT("%d ", sc->stripes);
315 for (i = 0; i < sc->stripes; i++) {
316 DMEMIT("%s ", sc->stripe[i].dev->name);
317 buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
318 'D' : 'A';
319 }
320 buffer[i] = '\0';
321 DMEMIT("1 %s", buffer);
322 break;
323
324 case STATUSTYPE_TABLE:
325 DMEMIT("%d %llu", sc->stripes,
326 (unsigned long long)sc->chunk_mask + 1);
327 for (i = 0; i < sc->stripes; i++)
328 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
329 (unsigned long long)sc->stripe[i].physical_start);
330 break;
331 }
332 return 0;
333}
334
335static int stripe_end_io(struct dm_target *ti, struct bio *bio,
336 int error, union map_info *map_context)
337{
338 unsigned i;
339 char major_minor[16];
340 struct stripe_c *sc = ti->private;
341
342 if (!error)
343 return 0; /* I/O complete */
344
345 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
346 return error;
347
348 if (error == -EOPNOTSUPP)
349 return error;
350
351 memset(major_minor, 0, sizeof(major_minor));
352 sprintf(major_minor, "%d:%d",
353 MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
354 MINOR(disk_devt(bio->bi_bdev->bd_disk)));
355
356 /*
357 * Test to see which stripe drive triggered the event
358 * and increment error count for all stripes on that device.
359 * If the error count for a given device exceeds the threshold
360 * value we will no longer trigger any further events.
361 */
362 for (i = 0; i < sc->stripes; i++)
363 if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
364 atomic_inc(&(sc->stripe[i].error_count));
365 if (atomic_read(&(sc->stripe[i].error_count)) <
366 DM_IO_ERROR_THRESHOLD)
367 schedule_work(&sc->trigger_event);
368 }
369
370 return error;
371}
372
373static int stripe_iterate_devices(struct dm_target *ti,
374 iterate_devices_callout_fn fn, void *data)
375{
376 struct stripe_c *sc = ti->private;
377 int ret = 0;
378 unsigned i = 0;
379
380 do {
381 ret = fn(ti, sc->stripe[i].dev,
382 sc->stripe[i].physical_start,
383 sc->stripe_width, data);
384 } while (!ret && ++i < sc->stripes);
385
386 return ret;
387}
388
389static void stripe_io_hints(struct dm_target *ti,
390 struct queue_limits *limits)
391{
392 struct stripe_c *sc = ti->private;
393 unsigned chunk_size = (sc->chunk_mask + 1) << 9;
394
395 blk_limits_io_min(limits, chunk_size);
396 blk_limits_io_opt(limits, chunk_size * sc->stripes);
397}
398
399static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
400 struct bio_vec *biovec, int max_size)
401{
402 struct stripe_c *sc = ti->private;
403 sector_t bvm_sector = bvm->bi_sector;
404 uint32_t stripe;
405 struct request_queue *q;
406
407 stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
408
409 q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
410 if (!q->merge_bvec_fn)
411 return max_size;
412
413 bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
414 bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
415
416 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
417}
418
419static struct target_type stripe_target = {
420 .name = "striped",
421 .version = {1, 4, 0},
422 .module = THIS_MODULE,
423 .ctr = stripe_ctr,
424 .dtr = stripe_dtr,
425 .map = stripe_map,
426 .end_io = stripe_end_io,
427 .status = stripe_status,
428 .iterate_devices = stripe_iterate_devices,
429 .io_hints = stripe_io_hints,
430 .merge = stripe_merge,
431};
432
433int __init dm_stripe_init(void)
434{
435 int r;
436
437 r = dm_register_target(&stripe_target);
438 if (r < 0) {
439 DMWARN("target registration failed");
440 return r;
441 }
442
443 return r;
444}
445
446void dm_stripe_exit(void)
447{
448 dm_unregister_target(&stripe_target);
449}