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