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