1 /* 2 raid0.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 Copyright (C) 1999, 2000 Ingo Molnar, Red Hat 7 8 RAID-0 management functions. 9 10 This program is free software; you can redistribute it and/or modify 11 it under the terms of the GNU General Public License as published by 12 the Free Software Foundation; either version 2, or (at your option) 13 any later version. 14 15 You should have received a copy of the GNU General Public License 16 (for example /usr/src/linux/COPYING); if not, write to the Free 17 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18 */ 19 20 #include <linux/blkdev.h> 21 #include <linux/seq_file.h> 22 #include <linux/module.h> 23 #include <linux/slab.h> 24 #include "md.h" 25 #include "raid0.h" 26 #include "raid5.h" 27 28 static int raid0_congested(struct mddev *mddev, int bits) 29 { 30 struct r0conf *conf = mddev->private; 31 struct md_rdev **devlist = conf->devlist; 32 int raid_disks = conf->strip_zone[0].nb_dev; 33 int i, ret = 0; 34 35 for (i = 0; i < raid_disks && !ret ; i++) { 36 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 37 38 ret |= bdi_congested(&q->backing_dev_info, bits); 39 } 40 return ret; 41 } 42 43 /* 44 * inform the user of the raid configuration 45 */ 46 static void dump_zones(struct mddev *mddev) 47 { 48 int j, k; 49 sector_t zone_size = 0; 50 sector_t zone_start = 0; 51 char b[BDEVNAME_SIZE]; 52 struct r0conf *conf = mddev->private; 53 int raid_disks = conf->strip_zone[0].nb_dev; 54 printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n", 55 mdname(mddev), 56 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); 57 for (j = 0; j < conf->nr_strip_zones; j++) { 58 printk(KERN_INFO "md: zone%d=[", j); 59 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 60 printk(KERN_CONT "%s%s", k?"/":"", 61 bdevname(conf->devlist[j*raid_disks 62 + k]->bdev, b)); 63 printk(KERN_CONT "]\n"); 64 65 zone_size = conf->strip_zone[j].zone_end - zone_start; 66 printk(KERN_INFO " zone-offset=%10lluKB, " 67 "device-offset=%10lluKB, size=%10lluKB\n", 68 (unsigned long long)zone_start>>1, 69 (unsigned long long)conf->strip_zone[j].dev_start>>1, 70 (unsigned long long)zone_size>>1); 71 zone_start = conf->strip_zone[j].zone_end; 72 } 73 } 74 75 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 76 { 77 int i, c, err; 78 sector_t curr_zone_end, sectors; 79 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev; 80 struct strip_zone *zone; 81 int cnt; 82 char b[BDEVNAME_SIZE]; 83 char b2[BDEVNAME_SIZE]; 84 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 85 unsigned short blksize = 512; 86 87 *private_conf = ERR_PTR(-ENOMEM); 88 if (!conf) 89 return -ENOMEM; 90 rdev_for_each(rdev1, mddev) { 91 pr_debug("md/raid0:%s: looking at %s\n", 92 mdname(mddev), 93 bdevname(rdev1->bdev, b)); 94 c = 0; 95 96 /* round size to chunk_size */ 97 sectors = rdev1->sectors; 98 sector_div(sectors, mddev->chunk_sectors); 99 rdev1->sectors = sectors * mddev->chunk_sectors; 100 101 blksize = max(blksize, queue_logical_block_size( 102 rdev1->bdev->bd_disk->queue)); 103 104 rdev_for_each(rdev2, mddev) { 105 pr_debug("md/raid0:%s: comparing %s(%llu)" 106 " with %s(%llu)\n", 107 mdname(mddev), 108 bdevname(rdev1->bdev,b), 109 (unsigned long long)rdev1->sectors, 110 bdevname(rdev2->bdev,b2), 111 (unsigned long long)rdev2->sectors); 112 if (rdev2 == rdev1) { 113 pr_debug("md/raid0:%s: END\n", 114 mdname(mddev)); 115 break; 116 } 117 if (rdev2->sectors == rdev1->sectors) { 118 /* 119 * Not unique, don't count it as a new 120 * group 121 */ 122 pr_debug("md/raid0:%s: EQUAL\n", 123 mdname(mddev)); 124 c = 1; 125 break; 126 } 127 pr_debug("md/raid0:%s: NOT EQUAL\n", 128 mdname(mddev)); 129 } 130 if (!c) { 131 pr_debug("md/raid0:%s: ==> UNIQUE\n", 132 mdname(mddev)); 133 conf->nr_strip_zones++; 134 pr_debug("md/raid0:%s: %d zones\n", 135 mdname(mddev), conf->nr_strip_zones); 136 } 137 } 138 pr_debug("md/raid0:%s: FINAL %d zones\n", 139 mdname(mddev), conf->nr_strip_zones); 140 /* 141 * now since we have the hard sector sizes, we can make sure 142 * chunk size is a multiple of that sector size 143 */ 144 if ((mddev->chunk_sectors << 9) % blksize) { 145 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not multiple of block size %d\n", 146 mdname(mddev), 147 mddev->chunk_sectors << 9, blksize); 148 err = -EINVAL; 149 goto abort; 150 } 151 152 err = -ENOMEM; 153 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 154 conf->nr_strip_zones, GFP_KERNEL); 155 if (!conf->strip_zone) 156 goto abort; 157 conf->devlist = kzalloc(sizeof(struct md_rdev*)* 158 conf->nr_strip_zones*mddev->raid_disks, 159 GFP_KERNEL); 160 if (!conf->devlist) 161 goto abort; 162 163 /* The first zone must contain all devices, so here we check that 164 * there is a proper alignment of slots to devices and find them all 165 */ 166 zone = &conf->strip_zone[0]; 167 cnt = 0; 168 smallest = NULL; 169 dev = conf->devlist; 170 err = -EINVAL; 171 rdev_for_each(rdev1, mddev) { 172 int j = rdev1->raid_disk; 173 174 if (mddev->level == 10) { 175 /* taking over a raid10-n2 array */ 176 j /= 2; 177 rdev1->new_raid_disk = j; 178 } 179 180 if (mddev->level == 1) { 181 /* taiking over a raid1 array- 182 * we have only one active disk 183 */ 184 j = 0; 185 rdev1->new_raid_disk = j; 186 } 187 188 if (j < 0) { 189 printk(KERN_ERR 190 "md/raid0:%s: remove inactive devices before converting to RAID0\n", 191 mdname(mddev)); 192 goto abort; 193 } 194 if (j >= mddev->raid_disks) { 195 printk(KERN_ERR "md/raid0:%s: bad disk number %d - " 196 "aborting!\n", mdname(mddev), j); 197 goto abort; 198 } 199 if (dev[j]) { 200 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " 201 "aborting!\n", mdname(mddev), j); 202 goto abort; 203 } 204 dev[j] = rdev1; 205 206 if (!smallest || (rdev1->sectors < smallest->sectors)) 207 smallest = rdev1; 208 cnt++; 209 } 210 if (cnt != mddev->raid_disks) { 211 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " 212 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks); 213 goto abort; 214 } 215 zone->nb_dev = cnt; 216 zone->zone_end = smallest->sectors * cnt; 217 218 curr_zone_end = zone->zone_end; 219 220 /* now do the other zones */ 221 for (i = 1; i < conf->nr_strip_zones; i++) 222 { 223 int j; 224 225 zone = conf->strip_zone + i; 226 dev = conf->devlist + i * mddev->raid_disks; 227 228 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 229 zone->dev_start = smallest->sectors; 230 smallest = NULL; 231 c = 0; 232 233 for (j=0; j<cnt; j++) { 234 rdev = conf->devlist[j]; 235 if (rdev->sectors <= zone->dev_start) { 236 pr_debug("md/raid0:%s: checking %s ... nope\n", 237 mdname(mddev), 238 bdevname(rdev->bdev, b)); 239 continue; 240 } 241 pr_debug("md/raid0:%s: checking %s ..." 242 " contained as device %d\n", 243 mdname(mddev), 244 bdevname(rdev->bdev, b), c); 245 dev[c] = rdev; 246 c++; 247 if (!smallest || rdev->sectors < smallest->sectors) { 248 smallest = rdev; 249 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 250 mdname(mddev), 251 (unsigned long long)rdev->sectors); 252 } 253 } 254 255 zone->nb_dev = c; 256 sectors = (smallest->sectors - zone->dev_start) * c; 257 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 258 mdname(mddev), 259 zone->nb_dev, (unsigned long long)sectors); 260 261 curr_zone_end += sectors; 262 zone->zone_end = curr_zone_end; 263 264 pr_debug("md/raid0:%s: current zone start: %llu\n", 265 mdname(mddev), 266 (unsigned long long)smallest->sectors); 267 } 268 269 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 270 *private_conf = conf; 271 272 return 0; 273 abort: 274 kfree(conf->strip_zone); 275 kfree(conf->devlist); 276 kfree(conf); 277 *private_conf = ERR_PTR(err); 278 return err; 279 } 280 281 /* Find the zone which holds a particular offset 282 * Update *sectorp to be an offset in that zone 283 */ 284 static struct strip_zone *find_zone(struct r0conf *conf, 285 sector_t *sectorp) 286 { 287 int i; 288 struct strip_zone *z = conf->strip_zone; 289 sector_t sector = *sectorp; 290 291 for (i = 0; i < conf->nr_strip_zones; i++) 292 if (sector < z[i].zone_end) { 293 if (i) 294 *sectorp = sector - z[i-1].zone_end; 295 return z + i; 296 } 297 BUG(); 298 } 299 300 /* 301 * remaps the bio to the target device. we separate two flows. 302 * power 2 flow and a general flow for the sake of performance 303 */ 304 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 305 sector_t sector, sector_t *sector_offset) 306 { 307 unsigned int sect_in_chunk; 308 sector_t chunk; 309 struct r0conf *conf = mddev->private; 310 int raid_disks = conf->strip_zone[0].nb_dev; 311 unsigned int chunk_sects = mddev->chunk_sectors; 312 313 if (is_power_of_2(chunk_sects)) { 314 int chunksect_bits = ffz(~chunk_sects); 315 /* find the sector offset inside the chunk */ 316 sect_in_chunk = sector & (chunk_sects - 1); 317 sector >>= chunksect_bits; 318 /* chunk in zone */ 319 chunk = *sector_offset; 320 /* quotient is the chunk in real device*/ 321 sector_div(chunk, zone->nb_dev << chunksect_bits); 322 } else{ 323 sect_in_chunk = sector_div(sector, chunk_sects); 324 chunk = *sector_offset; 325 sector_div(chunk, chunk_sects * zone->nb_dev); 326 } 327 /* 328 * position the bio over the real device 329 * real sector = chunk in device + starting of zone 330 * + the position in the chunk 331 */ 332 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 333 return conf->devlist[(zone - conf->strip_zone)*raid_disks 334 + sector_div(sector, zone->nb_dev)]; 335 } 336 337 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 338 { 339 sector_t array_sectors = 0; 340 struct md_rdev *rdev; 341 342 WARN_ONCE(sectors || raid_disks, 343 "%s does not support generic reshape\n", __func__); 344 345 rdev_for_each(rdev, mddev) 346 array_sectors += (rdev->sectors & 347 ~(sector_t)(mddev->chunk_sectors-1)); 348 349 return array_sectors; 350 } 351 352 static void raid0_free(struct mddev *mddev, void *priv); 353 354 static int raid0_run(struct mddev *mddev) 355 { 356 struct r0conf *conf; 357 int ret; 358 359 if (mddev->chunk_sectors == 0) { 360 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", 361 mdname(mddev)); 362 return -EINVAL; 363 } 364 if (md_check_no_bitmap(mddev)) 365 return -EINVAL; 366 367 /* if private is not null, we are here after takeover */ 368 if (mddev->private == NULL) { 369 ret = create_strip_zones(mddev, &conf); 370 if (ret < 0) 371 return ret; 372 mddev->private = conf; 373 } 374 conf = mddev->private; 375 if (mddev->queue) { 376 struct md_rdev *rdev; 377 bool discard_supported = false; 378 379 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 380 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); 381 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors); 382 383 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 384 blk_queue_io_opt(mddev->queue, 385 (mddev->chunk_sectors << 9) * mddev->raid_disks); 386 387 rdev_for_each(rdev, mddev) { 388 disk_stack_limits(mddev->gendisk, rdev->bdev, 389 rdev->data_offset << 9); 390 if (blk_queue_discard(bdev_get_queue(rdev->bdev))) 391 discard_supported = true; 392 } 393 if (!discard_supported) 394 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 395 else 396 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 397 } 398 399 /* calculate array device size */ 400 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 401 402 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", 403 mdname(mddev), 404 (unsigned long long)mddev->array_sectors); 405 406 if (mddev->queue) { 407 /* calculate the max read-ahead size. 408 * For read-ahead of large files to be effective, we need to 409 * readahead at least twice a whole stripe. i.e. number of devices 410 * multiplied by chunk size times 2. 411 * If an individual device has an ra_pages greater than the 412 * chunk size, then we will not drive that device as hard as it 413 * wants. We consider this a configuration error: a larger 414 * chunksize should be used in that case. 415 */ 416 int stripe = mddev->raid_disks * 417 (mddev->chunk_sectors << 9) / PAGE_SIZE; 418 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 419 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 420 } 421 422 dump_zones(mddev); 423 424 ret = md_integrity_register(mddev); 425 426 return ret; 427 } 428 429 static void raid0_free(struct mddev *mddev, void *priv) 430 { 431 struct r0conf *conf = priv; 432 433 kfree(conf->strip_zone); 434 kfree(conf->devlist); 435 kfree(conf); 436 } 437 438 /* 439 * Is io distribute over 1 or more chunks ? 440 */ 441 static inline int is_io_in_chunk_boundary(struct mddev *mddev, 442 unsigned int chunk_sects, struct bio *bio) 443 { 444 if (likely(is_power_of_2(chunk_sects))) { 445 return chunk_sects >= 446 ((bio->bi_iter.bi_sector & (chunk_sects-1)) 447 + bio_sectors(bio)); 448 } else{ 449 sector_t sector = bio->bi_iter.bi_sector; 450 return chunk_sects >= (sector_div(sector, chunk_sects) 451 + bio_sectors(bio)); 452 } 453 } 454 455 static void raid0_make_request(struct mddev *mddev, struct bio *bio) 456 { 457 struct strip_zone *zone; 458 struct md_rdev *tmp_dev; 459 struct bio *split; 460 461 if (unlikely(bio->bi_rw & REQ_FLUSH)) { 462 md_flush_request(mddev, bio); 463 return; 464 } 465 466 do { 467 sector_t sector = bio->bi_iter.bi_sector; 468 unsigned chunk_sects = mddev->chunk_sectors; 469 470 unsigned sectors = chunk_sects - 471 (likely(is_power_of_2(chunk_sects)) 472 ? (sector & (chunk_sects-1)) 473 : sector_div(sector, chunk_sects)); 474 475 /* Restore due to sector_div */ 476 sector = bio->bi_iter.bi_sector; 477 478 if (sectors < bio_sectors(bio)) { 479 split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set); 480 bio_chain(split, bio); 481 } else { 482 split = bio; 483 } 484 485 zone = find_zone(mddev->private, §or); 486 tmp_dev = map_sector(mddev, zone, sector, §or); 487 split->bi_bdev = tmp_dev->bdev; 488 split->bi_iter.bi_sector = sector + zone->dev_start + 489 tmp_dev->data_offset; 490 491 if (unlikely((split->bi_rw & REQ_DISCARD) && 492 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) { 493 /* Just ignore it */ 494 bio_endio(split); 495 } else 496 generic_make_request(split); 497 } while (split != bio); 498 } 499 500 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 501 { 502 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 503 return; 504 } 505 506 static void *raid0_takeover_raid45(struct mddev *mddev) 507 { 508 struct md_rdev *rdev; 509 struct r0conf *priv_conf; 510 511 if (mddev->degraded != 1) { 512 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 513 mdname(mddev), 514 mddev->degraded); 515 return ERR_PTR(-EINVAL); 516 } 517 518 rdev_for_each(rdev, mddev) { 519 /* check slot number for a disk */ 520 if (rdev->raid_disk == mddev->raid_disks-1) { 521 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n", 522 mdname(mddev)); 523 return ERR_PTR(-EINVAL); 524 } 525 rdev->sectors = mddev->dev_sectors; 526 } 527 528 /* Set new parameters */ 529 mddev->new_level = 0; 530 mddev->new_layout = 0; 531 mddev->new_chunk_sectors = mddev->chunk_sectors; 532 mddev->raid_disks--; 533 mddev->delta_disks = -1; 534 /* make sure it will be not marked as dirty */ 535 mddev->recovery_cp = MaxSector; 536 537 create_strip_zones(mddev, &priv_conf); 538 return priv_conf; 539 } 540 541 static void *raid0_takeover_raid10(struct mddev *mddev) 542 { 543 struct r0conf *priv_conf; 544 545 /* Check layout: 546 * - far_copies must be 1 547 * - near_copies must be 2 548 * - disks number must be even 549 * - all mirrors must be already degraded 550 */ 551 if (mddev->layout != ((1 << 8) + 2)) { 552 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n", 553 mdname(mddev), 554 mddev->layout); 555 return ERR_PTR(-EINVAL); 556 } 557 if (mddev->raid_disks & 1) { 558 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n", 559 mdname(mddev)); 560 return ERR_PTR(-EINVAL); 561 } 562 if (mddev->degraded != (mddev->raid_disks>>1)) { 563 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n", 564 mdname(mddev)); 565 return ERR_PTR(-EINVAL); 566 } 567 568 /* Set new parameters */ 569 mddev->new_level = 0; 570 mddev->new_layout = 0; 571 mddev->new_chunk_sectors = mddev->chunk_sectors; 572 mddev->delta_disks = - mddev->raid_disks / 2; 573 mddev->raid_disks += mddev->delta_disks; 574 mddev->degraded = 0; 575 /* make sure it will be not marked as dirty */ 576 mddev->recovery_cp = MaxSector; 577 578 create_strip_zones(mddev, &priv_conf); 579 return priv_conf; 580 } 581 582 static void *raid0_takeover_raid1(struct mddev *mddev) 583 { 584 struct r0conf *priv_conf; 585 int chunksect; 586 587 /* Check layout: 588 * - (N - 1) mirror drives must be already faulty 589 */ 590 if ((mddev->raid_disks - 1) != mddev->degraded) { 591 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 592 mdname(mddev)); 593 return ERR_PTR(-EINVAL); 594 } 595 596 /* 597 * a raid1 doesn't have the notion of chunk size, so 598 * figure out the largest suitable size we can use. 599 */ 600 chunksect = 64 * 2; /* 64K by default */ 601 602 /* The array must be an exact multiple of chunksize */ 603 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 604 chunksect >>= 1; 605 606 if ((chunksect << 9) < PAGE_SIZE) 607 /* array size does not allow a suitable chunk size */ 608 return ERR_PTR(-EINVAL); 609 610 /* Set new parameters */ 611 mddev->new_level = 0; 612 mddev->new_layout = 0; 613 mddev->new_chunk_sectors = chunksect; 614 mddev->chunk_sectors = chunksect; 615 mddev->delta_disks = 1 - mddev->raid_disks; 616 mddev->raid_disks = 1; 617 /* make sure it will be not marked as dirty */ 618 mddev->recovery_cp = MaxSector; 619 620 create_strip_zones(mddev, &priv_conf); 621 return priv_conf; 622 } 623 624 static void *raid0_takeover(struct mddev *mddev) 625 { 626 /* raid0 can take over: 627 * raid4 - if all data disks are active. 628 * raid5 - providing it is Raid4 layout and one disk is faulty 629 * raid10 - assuming we have all necessary active disks 630 * raid1 - with (N -1) mirror drives faulty 631 */ 632 633 if (mddev->bitmap) { 634 printk(KERN_ERR "md/raid0: %s: cannot takeover array with bitmap\n", 635 mdname(mddev)); 636 return ERR_PTR(-EBUSY); 637 } 638 if (mddev->level == 4) 639 return raid0_takeover_raid45(mddev); 640 641 if (mddev->level == 5) { 642 if (mddev->layout == ALGORITHM_PARITY_N) 643 return raid0_takeover_raid45(mddev); 644 645 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 646 mdname(mddev), ALGORITHM_PARITY_N); 647 } 648 649 if (mddev->level == 10) 650 return raid0_takeover_raid10(mddev); 651 652 if (mddev->level == 1) 653 return raid0_takeover_raid1(mddev); 654 655 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n", 656 mddev->level); 657 658 return ERR_PTR(-EINVAL); 659 } 660 661 static void raid0_quiesce(struct mddev *mddev, int state) 662 { 663 } 664 665 static struct md_personality raid0_personality= 666 { 667 .name = "raid0", 668 .level = 0, 669 .owner = THIS_MODULE, 670 .make_request = raid0_make_request, 671 .run = raid0_run, 672 .free = raid0_free, 673 .status = raid0_status, 674 .size = raid0_size, 675 .takeover = raid0_takeover, 676 .quiesce = raid0_quiesce, 677 .congested = raid0_congested, 678 }; 679 680 static int __init raid0_init (void) 681 { 682 return register_md_personality (&raid0_personality); 683 } 684 685 static void raid0_exit (void) 686 { 687 unregister_md_personality (&raid0_personality); 688 } 689 690 module_init(raid0_init); 691 module_exit(raid0_exit); 692 MODULE_LICENSE("GPL"); 693 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 694 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 695 MODULE_ALIAS("md-raid0"); 696 MODULE_ALIAS("md-level-0"); 697