1 /* 2 * Interface to Linux block layer for MTD 'translation layers'. 3 * 4 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 19 * 20 */ 21 22 #include <linux/kernel.h> 23 #include <linux/slab.h> 24 #include <linux/module.h> 25 #include <linux/list.h> 26 #include <linux/fs.h> 27 #include <linux/mtd/blktrans.h> 28 #include <linux/mtd/mtd.h> 29 #include <linux/blkdev.h> 30 #include <linux/blkpg.h> 31 #include <linux/spinlock.h> 32 #include <linux/hdreg.h> 33 #include <linux/mutex.h> 34 #include <linux/uaccess.h> 35 36 #include "mtdcore.h" 37 38 static LIST_HEAD(blktrans_majors); 39 static DEFINE_MUTEX(blktrans_ref_mutex); 40 41 static void blktrans_dev_release(struct kref *kref) 42 { 43 struct mtd_blktrans_dev *dev = 44 container_of(kref, struct mtd_blktrans_dev, ref); 45 46 dev->disk->private_data = NULL; 47 blk_cleanup_queue(dev->rq); 48 put_disk(dev->disk); 49 list_del(&dev->list); 50 kfree(dev); 51 } 52 53 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk) 54 { 55 struct mtd_blktrans_dev *dev; 56 57 mutex_lock(&blktrans_ref_mutex); 58 dev = disk->private_data; 59 60 if (!dev) 61 goto unlock; 62 kref_get(&dev->ref); 63 unlock: 64 mutex_unlock(&blktrans_ref_mutex); 65 return dev; 66 } 67 68 static void blktrans_dev_put(struct mtd_blktrans_dev *dev) 69 { 70 mutex_lock(&blktrans_ref_mutex); 71 kref_put(&dev->ref, blktrans_dev_release); 72 mutex_unlock(&blktrans_ref_mutex); 73 } 74 75 76 static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr, 77 struct mtd_blktrans_dev *dev, 78 struct request *req) 79 { 80 unsigned long block, nsect; 81 char *buf; 82 83 block = blk_rq_pos(req) << 9 >> tr->blkshift; 84 nsect = blk_rq_cur_bytes(req) >> tr->blkshift; 85 86 if (req_op(req) == REQ_OP_FLUSH) { 87 if (tr->flush(dev)) 88 return BLK_STS_IOERR; 89 return BLK_STS_OK; 90 } 91 92 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > 93 get_capacity(req->rq_disk)) 94 return BLK_STS_IOERR; 95 96 switch (req_op(req)) { 97 case REQ_OP_DISCARD: 98 if (tr->discard(dev, block, nsect)) 99 return BLK_STS_IOERR; 100 return BLK_STS_OK; 101 case REQ_OP_READ: 102 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); 103 for (; nsect > 0; nsect--, block++, buf += tr->blksize) { 104 if (tr->readsect(dev, block, buf)) { 105 kunmap(bio_page(req->bio)); 106 return BLK_STS_IOERR; 107 } 108 } 109 kunmap(bio_page(req->bio)); 110 rq_flush_dcache_pages(req); 111 return BLK_STS_OK; 112 case REQ_OP_WRITE: 113 if (!tr->writesect) 114 return BLK_STS_IOERR; 115 116 rq_flush_dcache_pages(req); 117 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); 118 for (; nsect > 0; nsect--, block++, buf += tr->blksize) { 119 if (tr->writesect(dev, block, buf)) { 120 kunmap(bio_page(req->bio)); 121 return BLK_STS_IOERR; 122 } 123 } 124 kunmap(bio_page(req->bio)); 125 return BLK_STS_OK; 126 default: 127 return BLK_STS_IOERR; 128 } 129 } 130 131 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) 132 { 133 return dev->bg_stop; 134 } 135 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); 136 137 static void mtd_blktrans_work(struct work_struct *work) 138 { 139 struct mtd_blktrans_dev *dev = 140 container_of(work, struct mtd_blktrans_dev, work); 141 struct mtd_blktrans_ops *tr = dev->tr; 142 struct request_queue *rq = dev->rq; 143 struct request *req = NULL; 144 int background_done = 0; 145 146 spin_lock_irq(rq->queue_lock); 147 148 while (1) { 149 blk_status_t res; 150 151 dev->bg_stop = false; 152 if (!req && !(req = blk_fetch_request(rq))) { 153 if (tr->background && !background_done) { 154 spin_unlock_irq(rq->queue_lock); 155 mutex_lock(&dev->lock); 156 tr->background(dev); 157 mutex_unlock(&dev->lock); 158 spin_lock_irq(rq->queue_lock); 159 /* 160 * Do background processing just once per idle 161 * period. 162 */ 163 background_done = !dev->bg_stop; 164 continue; 165 } 166 break; 167 } 168 169 spin_unlock_irq(rq->queue_lock); 170 171 mutex_lock(&dev->lock); 172 res = do_blktrans_request(dev->tr, dev, req); 173 mutex_unlock(&dev->lock); 174 175 spin_lock_irq(rq->queue_lock); 176 177 if (!__blk_end_request_cur(req, res)) 178 req = NULL; 179 180 background_done = 0; 181 } 182 183 spin_unlock_irq(rq->queue_lock); 184 } 185 186 static void mtd_blktrans_request(struct request_queue *rq) 187 { 188 struct mtd_blktrans_dev *dev; 189 struct request *req = NULL; 190 191 dev = rq->queuedata; 192 193 if (!dev) 194 while ((req = blk_fetch_request(rq)) != NULL) 195 __blk_end_request_all(req, BLK_STS_IOERR); 196 else 197 queue_work(dev->wq, &dev->work); 198 } 199 200 static int blktrans_open(struct block_device *bdev, fmode_t mode) 201 { 202 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 203 int ret = 0; 204 205 if (!dev) 206 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 207 208 mutex_lock(&mtd_table_mutex); 209 mutex_lock(&dev->lock); 210 211 if (dev->open) 212 goto unlock; 213 214 kref_get(&dev->ref); 215 __module_get(dev->tr->owner); 216 217 if (!dev->mtd) 218 goto unlock; 219 220 if (dev->tr->open) { 221 ret = dev->tr->open(dev); 222 if (ret) 223 goto error_put; 224 } 225 226 ret = __get_mtd_device(dev->mtd); 227 if (ret) 228 goto error_release; 229 dev->file_mode = mode; 230 231 unlock: 232 dev->open++; 233 mutex_unlock(&dev->lock); 234 mutex_unlock(&mtd_table_mutex); 235 blktrans_dev_put(dev); 236 return ret; 237 238 error_release: 239 if (dev->tr->release) 240 dev->tr->release(dev); 241 error_put: 242 module_put(dev->tr->owner); 243 kref_put(&dev->ref, blktrans_dev_release); 244 mutex_unlock(&dev->lock); 245 mutex_unlock(&mtd_table_mutex); 246 blktrans_dev_put(dev); 247 return ret; 248 } 249 250 static void blktrans_release(struct gendisk *disk, fmode_t mode) 251 { 252 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 253 254 if (!dev) 255 return; 256 257 mutex_lock(&mtd_table_mutex); 258 mutex_lock(&dev->lock); 259 260 if (--dev->open) 261 goto unlock; 262 263 kref_put(&dev->ref, blktrans_dev_release); 264 module_put(dev->tr->owner); 265 266 if (dev->mtd) { 267 if (dev->tr->release) 268 dev->tr->release(dev); 269 __put_mtd_device(dev->mtd); 270 } 271 unlock: 272 mutex_unlock(&dev->lock); 273 mutex_unlock(&mtd_table_mutex); 274 blktrans_dev_put(dev); 275 } 276 277 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 278 { 279 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 280 int ret = -ENXIO; 281 282 if (!dev) 283 return ret; 284 285 mutex_lock(&dev->lock); 286 287 if (!dev->mtd) 288 goto unlock; 289 290 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY; 291 unlock: 292 mutex_unlock(&dev->lock); 293 blktrans_dev_put(dev); 294 return ret; 295 } 296 297 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 298 unsigned int cmd, unsigned long arg) 299 { 300 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 301 int ret = -ENXIO; 302 303 if (!dev) 304 return ret; 305 306 mutex_lock(&dev->lock); 307 308 if (!dev->mtd) 309 goto unlock; 310 311 switch (cmd) { 312 case BLKFLSBUF: 313 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 314 break; 315 default: 316 ret = -ENOTTY; 317 } 318 unlock: 319 mutex_unlock(&dev->lock); 320 blktrans_dev_put(dev); 321 return ret; 322 } 323 324 static const struct block_device_operations mtd_block_ops = { 325 .owner = THIS_MODULE, 326 .open = blktrans_open, 327 .release = blktrans_release, 328 .ioctl = blktrans_ioctl, 329 .getgeo = blktrans_getgeo, 330 }; 331 332 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 333 { 334 struct mtd_blktrans_ops *tr = new->tr; 335 struct mtd_blktrans_dev *d; 336 int last_devnum = -1; 337 struct gendisk *gd; 338 int ret; 339 340 if (mutex_trylock(&mtd_table_mutex)) { 341 mutex_unlock(&mtd_table_mutex); 342 BUG(); 343 } 344 345 mutex_lock(&blktrans_ref_mutex); 346 list_for_each_entry(d, &tr->devs, list) { 347 if (new->devnum == -1) { 348 /* Use first free number */ 349 if (d->devnum != last_devnum+1) { 350 /* Found a free devnum. Plug it in here */ 351 new->devnum = last_devnum+1; 352 list_add_tail(&new->list, &d->list); 353 goto added; 354 } 355 } else if (d->devnum == new->devnum) { 356 /* Required number taken */ 357 mutex_unlock(&blktrans_ref_mutex); 358 return -EBUSY; 359 } else if (d->devnum > new->devnum) { 360 /* Required number was free */ 361 list_add_tail(&new->list, &d->list); 362 goto added; 363 } 364 last_devnum = d->devnum; 365 } 366 367 ret = -EBUSY; 368 if (new->devnum == -1) 369 new->devnum = last_devnum+1; 370 371 /* Check that the device and any partitions will get valid 372 * minor numbers and that the disk naming code below can cope 373 * with this number. */ 374 if (new->devnum > (MINORMASK >> tr->part_bits) || 375 (tr->part_bits && new->devnum >= 27 * 26)) { 376 mutex_unlock(&blktrans_ref_mutex); 377 goto error1; 378 } 379 380 list_add_tail(&new->list, &tr->devs); 381 added: 382 mutex_unlock(&blktrans_ref_mutex); 383 384 mutex_init(&new->lock); 385 kref_init(&new->ref); 386 if (!tr->writesect) 387 new->readonly = 1; 388 389 /* Create gendisk */ 390 ret = -ENOMEM; 391 gd = alloc_disk(1 << tr->part_bits); 392 393 if (!gd) 394 goto error2; 395 396 new->disk = gd; 397 gd->private_data = new; 398 gd->major = tr->major; 399 gd->first_minor = (new->devnum) << tr->part_bits; 400 gd->fops = &mtd_block_ops; 401 402 if (tr->part_bits) 403 if (new->devnum < 26) 404 snprintf(gd->disk_name, sizeof(gd->disk_name), 405 "%s%c", tr->name, 'a' + new->devnum); 406 else 407 snprintf(gd->disk_name, sizeof(gd->disk_name), 408 "%s%c%c", tr->name, 409 'a' - 1 + new->devnum / 26, 410 'a' + new->devnum % 26); 411 else 412 snprintf(gd->disk_name, sizeof(gd->disk_name), 413 "%s%d", tr->name, new->devnum); 414 415 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9); 416 417 /* Create the request queue */ 418 spin_lock_init(&new->queue_lock); 419 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 420 421 if (!new->rq) 422 goto error3; 423 424 if (tr->flush) 425 blk_queue_write_cache(new->rq, true, false); 426 427 new->rq->queuedata = new; 428 blk_queue_logical_block_size(new->rq, tr->blksize); 429 430 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq); 431 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq); 432 433 if (tr->discard) { 434 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq); 435 blk_queue_max_discard_sectors(new->rq, UINT_MAX); 436 } 437 438 gd->queue = new->rq; 439 440 /* Create processing workqueue */ 441 new->wq = alloc_workqueue("%s%d", 0, 0, 442 tr->name, new->mtd->index); 443 if (!new->wq) 444 goto error4; 445 INIT_WORK(&new->work, mtd_blktrans_work); 446 447 if (new->readonly) 448 set_disk_ro(gd, 1); 449 450 device_add_disk(&new->mtd->dev, gd); 451 452 if (new->disk_attributes) { 453 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 454 new->disk_attributes); 455 WARN_ON(ret); 456 } 457 return 0; 458 error4: 459 blk_cleanup_queue(new->rq); 460 error3: 461 put_disk(new->disk); 462 error2: 463 list_del(&new->list); 464 error1: 465 return ret; 466 } 467 468 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 469 { 470 unsigned long flags; 471 472 if (mutex_trylock(&mtd_table_mutex)) { 473 mutex_unlock(&mtd_table_mutex); 474 BUG(); 475 } 476 477 if (old->disk_attributes) 478 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 479 old->disk_attributes); 480 481 /* Stop new requests to arrive */ 482 del_gendisk(old->disk); 483 484 /* Stop workqueue. This will perform any pending request. */ 485 destroy_workqueue(old->wq); 486 487 /* Kill current requests */ 488 spin_lock_irqsave(&old->queue_lock, flags); 489 old->rq->queuedata = NULL; 490 blk_start_queue(old->rq); 491 spin_unlock_irqrestore(&old->queue_lock, flags); 492 493 /* If the device is currently open, tell trans driver to close it, 494 then put mtd device, and don't touch it again */ 495 mutex_lock(&old->lock); 496 if (old->open) { 497 if (old->tr->release) 498 old->tr->release(old); 499 __put_mtd_device(old->mtd); 500 } 501 502 old->mtd = NULL; 503 504 mutex_unlock(&old->lock); 505 blktrans_dev_put(old); 506 return 0; 507 } 508 509 static void blktrans_notify_remove(struct mtd_info *mtd) 510 { 511 struct mtd_blktrans_ops *tr; 512 struct mtd_blktrans_dev *dev, *next; 513 514 list_for_each_entry(tr, &blktrans_majors, list) 515 list_for_each_entry_safe(dev, next, &tr->devs, list) 516 if (dev->mtd == mtd) 517 tr->remove_dev(dev); 518 } 519 520 static void blktrans_notify_add(struct mtd_info *mtd) 521 { 522 struct mtd_blktrans_ops *tr; 523 524 if (mtd->type == MTD_ABSENT) 525 return; 526 527 list_for_each_entry(tr, &blktrans_majors, list) 528 tr->add_mtd(tr, mtd); 529 } 530 531 static struct mtd_notifier blktrans_notifier = { 532 .add = blktrans_notify_add, 533 .remove = blktrans_notify_remove, 534 }; 535 536 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 537 { 538 struct mtd_info *mtd; 539 int ret; 540 541 /* Register the notifier if/when the first device type is 542 registered, to prevent the link/init ordering from fucking 543 us over. */ 544 if (!blktrans_notifier.list.next) 545 register_mtd_user(&blktrans_notifier); 546 547 548 mutex_lock(&mtd_table_mutex); 549 550 ret = register_blkdev(tr->major, tr->name); 551 if (ret < 0) { 552 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 553 tr->name, tr->major, ret); 554 mutex_unlock(&mtd_table_mutex); 555 return ret; 556 } 557 558 if (ret) 559 tr->major = ret; 560 561 tr->blkshift = ffs(tr->blksize) - 1; 562 563 INIT_LIST_HEAD(&tr->devs); 564 list_add(&tr->list, &blktrans_majors); 565 566 mtd_for_each_device(mtd) 567 if (mtd->type != MTD_ABSENT) 568 tr->add_mtd(tr, mtd); 569 570 mutex_unlock(&mtd_table_mutex); 571 return 0; 572 } 573 574 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 575 { 576 struct mtd_blktrans_dev *dev, *next; 577 578 mutex_lock(&mtd_table_mutex); 579 580 /* Remove it from the list of active majors */ 581 list_del(&tr->list); 582 583 list_for_each_entry_safe(dev, next, &tr->devs, list) 584 tr->remove_dev(dev); 585 586 unregister_blkdev(tr->major, tr->name); 587 mutex_unlock(&mtd_table_mutex); 588 589 BUG_ON(!list_empty(&tr->devs)); 590 return 0; 591 } 592 593 static void __exit mtd_blktrans_exit(void) 594 { 595 /* No race here -- if someone's currently in register_mtd_blktrans 596 we're screwed anyway. */ 597 if (blktrans_notifier.list.next) 598 unregister_mtd_user(&blktrans_notifier); 599 } 600 601 module_exit(mtd_blktrans_exit); 602 603 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 604 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 605 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 606 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 607 608 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 609 MODULE_LICENSE("GPL"); 610 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 611