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