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1da177e4 LT |
1 | /* |
2 | linear.c : Multiple Devices driver for Linux | |
3 | Copyright (C) 1994-96 Marc ZYNGIER | |
4 | <zyngier@ufr-info-p7.ibp.fr> or | |
5 | <maz@gloups.fdn.fr> | |
6 | ||
7 | Linear mode management functions. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 2, or (at your option) | |
12 | any later version. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | (for example /usr/src/linux/COPYING); if not, write to the Free | |
16 | Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
17 | */ | |
18 | ||
bff61975 N |
19 | #include <linux/blkdev.h> |
20 | #include <linux/raid/md_u.h> | |
bff61975 | 21 | #include <linux/seq_file.h> |
43b2e5d8 | 22 | #include "md.h" |
ef740c37 | 23 | #include "linear.h" |
1da177e4 | 24 | |
1da177e4 LT |
25 | /* |
26 | * find which device holds a particular offset | |
27 | */ | |
28 | static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector) | |
29 | { | |
30 | dev_info_t *hash; | |
31 | linear_conf_t *conf = mddev_to_conf(mddev); | |
852c8bf4 | 32 | sector_t idx = sector >> conf->sector_shift; |
1da177e4 LT |
33 | |
34 | /* | |
35 | * sector_div(a,b) returns the remainer and sets a to a/b | |
36 | */ | |
852c8bf4 AN |
37 | (void)sector_div(idx, conf->spacing); |
38 | hash = conf->hash_table[idx]; | |
1da177e4 | 39 | |
6283815d | 40 | while (sector >= hash->num_sectors + hash->start_sector) |
1da177e4 LT |
41 | hash++; |
42 | return hash; | |
43 | } | |
44 | ||
45 | /** | |
15945fee | 46 | * linear_mergeable_bvec -- tell bio layer if two requests can be merged |
1da177e4 | 47 | * @q: request queue |
cc371e66 | 48 | * @bvm: properties of new bio |
1da177e4 LT |
49 | * @biovec: the request that could be merged to it. |
50 | * | |
51 | * Return amount of bytes we can take at this offset | |
52 | */ | |
cc371e66 AK |
53 | static int linear_mergeable_bvec(struct request_queue *q, |
54 | struct bvec_merge_data *bvm, | |
55 | struct bio_vec *biovec) | |
1da177e4 LT |
56 | { |
57 | mddev_t *mddev = q->queuedata; | |
58 | dev_info_t *dev0; | |
cc371e66 AK |
59 | unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9; |
60 | sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); | |
1da177e4 LT |
61 | |
62 | dev0 = which_dev(mddev, sector); | |
6283815d | 63 | maxsectors = dev0->num_sectors - (sector - dev0->start_sector); |
1da177e4 LT |
64 | |
65 | if (maxsectors < bio_sectors) | |
66 | maxsectors = 0; | |
67 | else | |
68 | maxsectors -= bio_sectors; | |
69 | ||
70 | if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0) | |
71 | return biovec->bv_len; | |
72 | /* The bytes available at this offset could be really big, | |
73 | * so we cap at 2^31 to avoid overflow */ | |
74 | if (maxsectors > (1 << (31-9))) | |
75 | return 1<<31; | |
76 | return maxsectors << 9; | |
77 | } | |
78 | ||
165125e1 | 79 | static void linear_unplug(struct request_queue *q) |
1da177e4 LT |
80 | { |
81 | mddev_t *mddev = q->queuedata; | |
82 | linear_conf_t *conf = mddev_to_conf(mddev); | |
83 | int i; | |
84 | ||
85 | for (i=0; i < mddev->raid_disks; i++) { | |
165125e1 | 86 | struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev); |
2ad8b1ef | 87 | blk_unplug(r_queue); |
1da177e4 LT |
88 | } |
89 | } | |
90 | ||
26be34dc N |
91 | static int linear_congested(void *data, int bits) |
92 | { | |
93 | mddev_t *mddev = data; | |
94 | linear_conf_t *conf = mddev_to_conf(mddev); | |
95 | int i, ret = 0; | |
96 | ||
97 | for (i = 0; i < mddev->raid_disks && !ret ; i++) { | |
165125e1 | 98 | struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev); |
26be34dc N |
99 | ret |= bdi_congested(&q->backing_dev_info, bits); |
100 | } | |
101 | return ret; | |
102 | } | |
103 | ||
80c3a6ce DW |
104 | static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks) |
105 | { | |
106 | linear_conf_t *conf = mddev_to_conf(mddev); | |
107 | ||
108 | WARN_ONCE(sectors || raid_disks, | |
109 | "%s does not support generic reshape\n", __func__); | |
110 | ||
111 | return conf->array_sectors; | |
112 | } | |
113 | ||
7c7546cc | 114 | static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks) |
1da177e4 LT |
115 | { |
116 | linear_conf_t *conf; | |
117 | dev_info_t **table; | |
118 | mdk_rdev_t *rdev; | |
119 | int i, nb_zone, cnt; | |
23242fbb | 120 | sector_t min_sectors; |
6283815d | 121 | sector_t curr_sector; |
1da177e4 | 122 | |
7c7546cc | 123 | conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(dev_info_t), |
1da177e4 LT |
124 | GFP_KERNEL); |
125 | if (!conf) | |
7c7546cc N |
126 | return NULL; |
127 | ||
1da177e4 | 128 | cnt = 0; |
d6e22150 | 129 | conf->array_sectors = 0; |
1da177e4 | 130 | |
159ec1fc | 131 | list_for_each_entry(rdev, &mddev->disks, same_set) { |
1da177e4 LT |
132 | int j = rdev->raid_disk; |
133 | dev_info_t *disk = conf->disks + j; | |
134 | ||
13864515 | 135 | if (j < 0 || j >= raid_disks || disk->rdev) { |
1da177e4 LT |
136 | printk("linear: disk numbering problem. Aborting!\n"); |
137 | goto out; | |
138 | } | |
139 | ||
140 | disk->rdev = rdev; | |
141 | ||
142 | blk_queue_stack_limits(mddev->queue, | |
143 | rdev->bdev->bd_disk->queue); | |
144 | /* as we don't honour merge_bvec_fn, we must never risk | |
145 | * violating it, so limit ->max_sector to one PAGE, as | |
146 | * a one page request is never in violation. | |
147 | */ | |
148 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
149 | mddev->queue->max_sectors > (PAGE_SIZE>>9)) | |
150 | blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
151 | ||
dd8ac336 AN |
152 | disk->num_sectors = rdev->sectors; |
153 | conf->array_sectors += rdev->sectors; | |
1da177e4 | 154 | |
1da177e4 LT |
155 | cnt++; |
156 | } | |
7c7546cc | 157 | if (cnt != raid_disks) { |
1da177e4 LT |
158 | printk("linear: not enough drives present. Aborting!\n"); |
159 | goto out; | |
160 | } | |
161 | ||
23242fbb AN |
162 | min_sectors = conf->array_sectors; |
163 | sector_div(min_sectors, PAGE_SIZE/sizeof(struct dev_info *)); | |
f1cd14ae AN |
164 | if (min_sectors == 0) |
165 | min_sectors = 1; | |
15945fee | 166 | |
23242fbb | 167 | /* min_sectors is the minimum spacing that will fit the hash |
15945fee N |
168 | * table in one PAGE. This may be much smaller than needed. |
169 | * We find the smallest non-terminal set of consecutive devices | |
23242fbb | 170 | * that is larger than min_sectors and use the size of that as |
15945fee N |
171 | * the actual spacing |
172 | */ | |
ab5bd5cb | 173 | conf->spacing = conf->array_sectors; |
15945fee | 174 | for (i=0; i < cnt-1 ; i++) { |
23242fbb | 175 | sector_t tmp = 0; |
15945fee | 176 | int j; |
23242fbb AN |
177 | for (j = i; j < cnt - 1 && tmp < min_sectors; j++) |
178 | tmp += conf->disks[j].num_sectors; | |
ab5bd5cb AN |
179 | if (tmp >= min_sectors && tmp < conf->spacing) |
180 | conf->spacing = tmp; | |
15945fee N |
181 | } |
182 | ||
ab5bd5cb | 183 | /* spacing may be too large for sector_div to work with, |
15945fee N |
184 | * so we might need to pre-shift |
185 | */ | |
ab5bd5cb | 186 | conf->sector_shift = 0; |
15945fee | 187 | if (sizeof(sector_t) > sizeof(u32)) { |
ab5bd5cb | 188 | sector_t space = conf->spacing; |
15945fee N |
189 | while (space > (sector_t)(~(u32)0)) { |
190 | space >>= 1; | |
ab5bd5cb | 191 | conf->sector_shift++; |
15945fee N |
192 | } |
193 | } | |
1da177e4 LT |
194 | /* |
195 | * This code was restructured to work around a gcc-2.95.3 internal | |
196 | * compiler error. Alter it with care. | |
197 | */ | |
198 | { | |
199 | sector_t sz; | |
200 | unsigned round; | |
201 | unsigned long base; | |
202 | ||
ab5bd5cb | 203 | sz = conf->array_sectors >> conf->sector_shift; |
15945fee | 204 | sz += 1; /* force round-up */ |
ab5bd5cb | 205 | base = conf->spacing >> conf->sector_shift; |
1da177e4 | 206 | round = sector_div(sz, base); |
15945fee | 207 | nb_zone = sz + (round ? 1 : 0); |
1da177e4 | 208 | } |
15945fee N |
209 | BUG_ON(nb_zone > PAGE_SIZE / sizeof(struct dev_info *)); |
210 | ||
211 | conf->hash_table = kmalloc (sizeof (struct dev_info *) * nb_zone, | |
1da177e4 LT |
212 | GFP_KERNEL); |
213 | if (!conf->hash_table) | |
214 | goto out; | |
215 | ||
216 | /* | |
217 | * Here we generate the linear hash table | |
15945fee | 218 | * First calculate the device offsets. |
1da177e4 | 219 | */ |
6283815d | 220 | conf->disks[0].start_sector = 0; |
a778b73f | 221 | for (i = 1; i < raid_disks; i++) |
6283815d AN |
222 | conf->disks[i].start_sector = |
223 | conf->disks[i-1].start_sector + | |
224 | conf->disks[i-1].num_sectors; | |
15945fee | 225 | |
1da177e4 | 226 | table = conf->hash_table; |
15945fee | 227 | i = 0; |
6283815d AN |
228 | for (curr_sector = 0; |
229 | curr_sector < conf->array_sectors; | |
ab5bd5cb | 230 | curr_sector += conf->spacing) { |
1da177e4 | 231 | |
a778b73f | 232 | while (i < raid_disks-1 && |
6283815d | 233 | curr_sector >= conf->disks[i+1].start_sector) |
15945fee | 234 | i++; |
1da177e4 | 235 | |
15945fee N |
236 | *table ++ = conf->disks + i; |
237 | } | |
238 | ||
ab5bd5cb AN |
239 | if (conf->sector_shift) { |
240 | conf->spacing >>= conf->sector_shift; | |
241 | /* round spacing up so that when we divide by it, | |
15945fee | 242 | * we err on the side of "too-low", which is safest. |
1da177e4 | 243 | */ |
ab5bd5cb | 244 | conf->spacing++; |
1da177e4 | 245 | } |
15945fee N |
246 | |
247 | BUG_ON(table - conf->hash_table > nb_zone); | |
1da177e4 | 248 | |
7c7546cc N |
249 | return conf; |
250 | ||
251 | out: | |
252 | kfree(conf); | |
253 | return NULL; | |
254 | } | |
255 | ||
256 | static int linear_run (mddev_t *mddev) | |
257 | { | |
258 | linear_conf_t *conf; | |
259 | ||
e7e72bf6 | 260 | mddev->queue->queue_lock = &mddev->queue->__queue_lock; |
7c7546cc N |
261 | conf = linear_conf(mddev, mddev->raid_disks); |
262 | ||
263 | if (!conf) | |
264 | return 1; | |
265 | mddev->private = conf; | |
80c3a6ce | 266 | mddev->array_sectors = linear_size(mddev, 0, 0); |
7c7546cc | 267 | |
1da177e4 LT |
268 | blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec); |
269 | mddev->queue->unplug_fn = linear_unplug; | |
26be34dc N |
270 | mddev->queue->backing_dev_info.congested_fn = linear_congested; |
271 | mddev->queue->backing_dev_info.congested_data = mddev; | |
1da177e4 | 272 | return 0; |
7c7546cc | 273 | } |
1da177e4 | 274 | |
7c7546cc N |
275 | static int linear_add(mddev_t *mddev, mdk_rdev_t *rdev) |
276 | { | |
277 | /* Adding a drive to a linear array allows the array to grow. | |
278 | * It is permitted if the new drive has a matching superblock | |
279 | * already on it, with raid_disk equal to raid_disks. | |
280 | * It is achieved by creating a new linear_private_data structure | |
281 | * and swapping it in in-place of the current one. | |
282 | * The current one is never freed until the array is stopped. | |
283 | * This avoids races. | |
284 | */ | |
285 | linear_conf_t *newconf; | |
286 | ||
a778b73f | 287 | if (rdev->saved_raid_disk != mddev->raid_disks) |
7c7546cc N |
288 | return -EINVAL; |
289 | ||
a778b73f N |
290 | rdev->raid_disk = rdev->saved_raid_disk; |
291 | ||
7c7546cc N |
292 | newconf = linear_conf(mddev,mddev->raid_disks+1); |
293 | ||
294 | if (!newconf) | |
295 | return -ENOMEM; | |
296 | ||
297 | newconf->prev = mddev_to_conf(mddev); | |
298 | mddev->private = newconf; | |
299 | mddev->raid_disks++; | |
80c3a6ce | 300 | mddev->array_sectors = linear_size(mddev, 0, 0); |
f233ea5c | 301 | set_capacity(mddev->gendisk, mddev->array_sectors); |
7c7546cc | 302 | return 0; |
1da177e4 LT |
303 | } |
304 | ||
305 | static int linear_stop (mddev_t *mddev) | |
306 | { | |
307 | linear_conf_t *conf = mddev_to_conf(mddev); | |
308 | ||
309 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ | |
7c7546cc N |
310 | do { |
311 | linear_conf_t *t = conf->prev; | |
312 | kfree(conf->hash_table); | |
313 | kfree(conf); | |
314 | conf = t; | |
315 | } while (conf); | |
1da177e4 LT |
316 | |
317 | return 0; | |
318 | } | |
319 | ||
165125e1 | 320 | static int linear_make_request (struct request_queue *q, struct bio *bio) |
1da177e4 | 321 | { |
a362357b | 322 | const int rw = bio_data_dir(bio); |
1da177e4 LT |
323 | mddev_t *mddev = q->queuedata; |
324 | dev_info_t *tmp_dev; | |
c9959059 | 325 | int cpu; |
1da177e4 | 326 | |
e5dcdd80 | 327 | if (unlikely(bio_barrier(bio))) { |
6712ecf8 | 328 | bio_endio(bio, -EOPNOTSUPP); |
e5dcdd80 N |
329 | return 0; |
330 | } | |
331 | ||
074a7aca TH |
332 | cpu = part_stat_lock(); |
333 | part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); | |
334 | part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], | |
335 | bio_sectors(bio)); | |
336 | part_stat_unlock(); | |
1da177e4 LT |
337 | |
338 | tmp_dev = which_dev(mddev, bio->bi_sector); | |
1da177e4 | 339 | |
6283815d AN |
340 | if (unlikely(bio->bi_sector >= (tmp_dev->num_sectors + |
341 | tmp_dev->start_sector) | |
342 | || (bio->bi_sector < | |
343 | tmp_dev->start_sector))) { | |
1da177e4 LT |
344 | char b[BDEVNAME_SIZE]; |
345 | ||
6283815d AN |
346 | printk("linear_make_request: Sector %llu out of bounds on " |
347 | "dev %s: %llu sectors, offset %llu\n", | |
348 | (unsigned long long)bio->bi_sector, | |
1da177e4 | 349 | bdevname(tmp_dev->rdev->bdev, b), |
6283815d AN |
350 | (unsigned long long)tmp_dev->num_sectors, |
351 | (unsigned long long)tmp_dev->start_sector); | |
6712ecf8 | 352 | bio_io_error(bio); |
1da177e4 LT |
353 | return 0; |
354 | } | |
355 | if (unlikely(bio->bi_sector + (bio->bi_size >> 9) > | |
6283815d | 356 | tmp_dev->start_sector + tmp_dev->num_sectors)) { |
1da177e4 LT |
357 | /* This bio crosses a device boundary, so we have to |
358 | * split it. | |
359 | */ | |
360 | struct bio_pair *bp; | |
6283815d | 361 | |
6feef531 | 362 | bp = bio_split(bio, |
6283815d AN |
363 | tmp_dev->start_sector + tmp_dev->num_sectors |
364 | - bio->bi_sector); | |
365 | ||
1da177e4 LT |
366 | if (linear_make_request(q, &bp->bio1)) |
367 | generic_make_request(&bp->bio1); | |
368 | if (linear_make_request(q, &bp->bio2)) | |
369 | generic_make_request(&bp->bio2); | |
370 | bio_pair_release(bp); | |
371 | return 0; | |
372 | } | |
373 | ||
374 | bio->bi_bdev = tmp_dev->rdev->bdev; | |
6283815d AN |
375 | bio->bi_sector = bio->bi_sector - tmp_dev->start_sector |
376 | + tmp_dev->rdev->data_offset; | |
1da177e4 LT |
377 | |
378 | return 1; | |
379 | } | |
380 | ||
381 | static void linear_status (struct seq_file *seq, mddev_t *mddev) | |
382 | { | |
383 | ||
1da177e4 LT |
384 | seq_printf(seq, " %dk rounding", mddev->chunk_size/1024); |
385 | } | |
386 | ||
387 | ||
2604b703 | 388 | static struct mdk_personality linear_personality = |
1da177e4 LT |
389 | { |
390 | .name = "linear", | |
2604b703 | 391 | .level = LEVEL_LINEAR, |
1da177e4 LT |
392 | .owner = THIS_MODULE, |
393 | .make_request = linear_make_request, | |
394 | .run = linear_run, | |
395 | .stop = linear_stop, | |
396 | .status = linear_status, | |
7c7546cc | 397 | .hot_add_disk = linear_add, |
80c3a6ce | 398 | .size = linear_size, |
1da177e4 LT |
399 | }; |
400 | ||
401 | static int __init linear_init (void) | |
402 | { | |
2604b703 | 403 | return register_md_personality (&linear_personality); |
1da177e4 LT |
404 | } |
405 | ||
406 | static void linear_exit (void) | |
407 | { | |
2604b703 | 408 | unregister_md_personality (&linear_personality); |
1da177e4 LT |
409 | } |
410 | ||
411 | ||
412 | module_init(linear_init); | |
413 | module_exit(linear_exit); | |
414 | MODULE_LICENSE("GPL"); | |
d9d166c2 N |
415 | MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ |
416 | MODULE_ALIAS("md-linear"); | |
2604b703 | 417 | MODULE_ALIAS("md-level--1"); |