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 return BLK_STS_OK; 117 default: 118 return BLK_STS_IOERR; 119 } 120 } 121 122 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) 123 { 124 return dev->bg_stop; 125 } 126 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); 127 128 static void mtd_blktrans_work(struct work_struct *work) 129 { 130 struct mtd_blktrans_dev *dev = 131 container_of(work, struct mtd_blktrans_dev, work); 132 struct mtd_blktrans_ops *tr = dev->tr; 133 struct request_queue *rq = dev->rq; 134 struct request *req = NULL; 135 int background_done = 0; 136 137 spin_lock_irq(rq->queue_lock); 138 139 while (1) { 140 blk_status_t res; 141 142 dev->bg_stop = false; 143 if (!req && !(req = blk_fetch_request(rq))) { 144 if (tr->background && !background_done) { 145 spin_unlock_irq(rq->queue_lock); 146 mutex_lock(&dev->lock); 147 tr->background(dev); 148 mutex_unlock(&dev->lock); 149 spin_lock_irq(rq->queue_lock); 150 /* 151 * Do background processing just once per idle 152 * period. 153 */ 154 background_done = !dev->bg_stop; 155 continue; 156 } 157 break; 158 } 159 160 spin_unlock_irq(rq->queue_lock); 161 162 mutex_lock(&dev->lock); 163 res = do_blktrans_request(dev->tr, dev, req); 164 mutex_unlock(&dev->lock); 165 166 spin_lock_irq(rq->queue_lock); 167 168 if (!__blk_end_request_cur(req, res)) 169 req = NULL; 170 171 background_done = 0; 172 } 173 174 spin_unlock_irq(rq->queue_lock); 175 } 176 177 static void mtd_blktrans_request(struct request_queue *rq) 178 { 179 struct mtd_blktrans_dev *dev; 180 struct request *req = NULL; 181 182 dev = rq->queuedata; 183 184 if (!dev) 185 while ((req = blk_fetch_request(rq)) != NULL) 186 __blk_end_request_all(req, BLK_STS_IOERR); 187 else 188 queue_work(dev->wq, &dev->work); 189 } 190 191 static int blktrans_open(struct block_device *bdev, fmode_t mode) 192 { 193 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 194 int ret = 0; 195 196 if (!dev) 197 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 198 199 mutex_lock(&mtd_table_mutex); 200 mutex_lock(&dev->lock); 201 202 if (dev->open) 203 goto unlock; 204 205 kref_get(&dev->ref); 206 __module_get(dev->tr->owner); 207 208 if (!dev->mtd) 209 goto unlock; 210 211 if (dev->tr->open) { 212 ret = dev->tr->open(dev); 213 if (ret) 214 goto error_put; 215 } 216 217 ret = __get_mtd_device(dev->mtd); 218 if (ret) 219 goto error_release; 220 dev->file_mode = mode; 221 222 unlock: 223 dev->open++; 224 mutex_unlock(&dev->lock); 225 mutex_unlock(&mtd_table_mutex); 226 blktrans_dev_put(dev); 227 return ret; 228 229 error_release: 230 if (dev->tr->release) 231 dev->tr->release(dev); 232 error_put: 233 module_put(dev->tr->owner); 234 kref_put(&dev->ref, blktrans_dev_release); 235 mutex_unlock(&dev->lock); 236 mutex_unlock(&mtd_table_mutex); 237 blktrans_dev_put(dev); 238 return ret; 239 } 240 241 static void blktrans_release(struct gendisk *disk, fmode_t mode) 242 { 243 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 244 245 if (!dev) 246 return; 247 248 mutex_lock(&mtd_table_mutex); 249 mutex_lock(&dev->lock); 250 251 if (--dev->open) 252 goto unlock; 253 254 kref_put(&dev->ref, blktrans_dev_release); 255 module_put(dev->tr->owner); 256 257 if (dev->mtd) { 258 if (dev->tr->release) 259 dev->tr->release(dev); 260 __put_mtd_device(dev->mtd); 261 } 262 unlock: 263 mutex_unlock(&dev->lock); 264 mutex_unlock(&mtd_table_mutex); 265 blktrans_dev_put(dev); 266 } 267 268 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 269 { 270 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 271 int ret = -ENXIO; 272 273 if (!dev) 274 return ret; 275 276 mutex_lock(&dev->lock); 277 278 if (!dev->mtd) 279 goto unlock; 280 281 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY; 282 unlock: 283 mutex_unlock(&dev->lock); 284 blktrans_dev_put(dev); 285 return ret; 286 } 287 288 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 289 unsigned int cmd, unsigned long arg) 290 { 291 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 292 int ret = -ENXIO; 293 294 if (!dev) 295 return ret; 296 297 mutex_lock(&dev->lock); 298 299 if (!dev->mtd) 300 goto unlock; 301 302 switch (cmd) { 303 case BLKFLSBUF: 304 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 305 break; 306 default: 307 ret = -ENOTTY; 308 } 309 unlock: 310 mutex_unlock(&dev->lock); 311 blktrans_dev_put(dev); 312 return ret; 313 } 314 315 static const struct block_device_operations mtd_block_ops = { 316 .owner = THIS_MODULE, 317 .open = blktrans_open, 318 .release = blktrans_release, 319 .ioctl = blktrans_ioctl, 320 .getgeo = blktrans_getgeo, 321 }; 322 323 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 324 { 325 struct mtd_blktrans_ops *tr = new->tr; 326 struct mtd_blktrans_dev *d; 327 int last_devnum = -1; 328 struct gendisk *gd; 329 int ret; 330 331 if (mutex_trylock(&mtd_table_mutex)) { 332 mutex_unlock(&mtd_table_mutex); 333 BUG(); 334 } 335 336 mutex_lock(&blktrans_ref_mutex); 337 list_for_each_entry(d, &tr->devs, list) { 338 if (new->devnum == -1) { 339 /* Use first free number */ 340 if (d->devnum != last_devnum+1) { 341 /* Found a free devnum. Plug it in here */ 342 new->devnum = last_devnum+1; 343 list_add_tail(&new->list, &d->list); 344 goto added; 345 } 346 } else if (d->devnum == new->devnum) { 347 /* Required number taken */ 348 mutex_unlock(&blktrans_ref_mutex); 349 return -EBUSY; 350 } else if (d->devnum > new->devnum) { 351 /* Required number was free */ 352 list_add_tail(&new->list, &d->list); 353 goto added; 354 } 355 last_devnum = d->devnum; 356 } 357 358 ret = -EBUSY; 359 if (new->devnum == -1) 360 new->devnum = last_devnum+1; 361 362 /* Check that the device and any partitions will get valid 363 * minor numbers and that the disk naming code below can cope 364 * with this number. */ 365 if (new->devnum > (MINORMASK >> tr->part_bits) || 366 (tr->part_bits && new->devnum >= 27 * 26)) { 367 mutex_unlock(&blktrans_ref_mutex); 368 goto error1; 369 } 370 371 list_add_tail(&new->list, &tr->devs); 372 added: 373 mutex_unlock(&blktrans_ref_mutex); 374 375 mutex_init(&new->lock); 376 kref_init(&new->ref); 377 if (!tr->writesect) 378 new->readonly = 1; 379 380 /* Create gendisk */ 381 ret = -ENOMEM; 382 gd = alloc_disk(1 << tr->part_bits); 383 384 if (!gd) 385 goto error2; 386 387 new->disk = gd; 388 gd->private_data = new; 389 gd->major = tr->major; 390 gd->first_minor = (new->devnum) << tr->part_bits; 391 gd->fops = &mtd_block_ops; 392 393 if (tr->part_bits) 394 if (new->devnum < 26) 395 snprintf(gd->disk_name, sizeof(gd->disk_name), 396 "%s%c", tr->name, 'a' + new->devnum); 397 else 398 snprintf(gd->disk_name, sizeof(gd->disk_name), 399 "%s%c%c", tr->name, 400 'a' - 1 + new->devnum / 26, 401 'a' + new->devnum % 26); 402 else 403 snprintf(gd->disk_name, sizeof(gd->disk_name), 404 "%s%d", tr->name, new->devnum); 405 406 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9); 407 408 /* Create the request queue */ 409 spin_lock_init(&new->queue_lock); 410 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 411 412 if (!new->rq) 413 goto error3; 414 415 if (tr->flush) 416 blk_queue_write_cache(new->rq, true, false); 417 418 new->rq->queuedata = new; 419 blk_queue_logical_block_size(new->rq, tr->blksize); 420 421 blk_queue_bounce_limit(new->rq, BLK_BOUNCE_HIGH); 422 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); 423 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq); 424 425 if (tr->discard) { 426 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 427 blk_queue_max_discard_sectors(new->rq, UINT_MAX); 428 } 429 430 gd->queue = new->rq; 431 432 /* Create processing workqueue */ 433 new->wq = alloc_workqueue("%s%d", 0, 0, 434 tr->name, new->mtd->index); 435 if (!new->wq) 436 goto error4; 437 INIT_WORK(&new->work, mtd_blktrans_work); 438 439 if (new->readonly) 440 set_disk_ro(gd, 1); 441 442 device_add_disk(&new->mtd->dev, gd); 443 444 if (new->disk_attributes) { 445 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 446 new->disk_attributes); 447 WARN_ON(ret); 448 } 449 return 0; 450 error4: 451 blk_cleanup_queue(new->rq); 452 error3: 453 put_disk(new->disk); 454 error2: 455 list_del(&new->list); 456 error1: 457 return ret; 458 } 459 460 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 461 { 462 unsigned long flags; 463 464 if (mutex_trylock(&mtd_table_mutex)) { 465 mutex_unlock(&mtd_table_mutex); 466 BUG(); 467 } 468 469 if (old->disk_attributes) 470 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 471 old->disk_attributes); 472 473 /* Stop new requests to arrive */ 474 del_gendisk(old->disk); 475 476 /* Stop workqueue. This will perform any pending request. */ 477 destroy_workqueue(old->wq); 478 479 /* Kill current requests */ 480 spin_lock_irqsave(&old->queue_lock, flags); 481 old->rq->queuedata = NULL; 482 blk_start_queue(old->rq); 483 spin_unlock_irqrestore(&old->queue_lock, flags); 484 485 /* If the device is currently open, tell trans driver to close it, 486 then put mtd device, and don't touch it again */ 487 mutex_lock(&old->lock); 488 if (old->open) { 489 if (old->tr->release) 490 old->tr->release(old); 491 __put_mtd_device(old->mtd); 492 } 493 494 old->mtd = NULL; 495 496 mutex_unlock(&old->lock); 497 blktrans_dev_put(old); 498 return 0; 499 } 500 501 static void blktrans_notify_remove(struct mtd_info *mtd) 502 { 503 struct mtd_blktrans_ops *tr; 504 struct mtd_blktrans_dev *dev, *next; 505 506 list_for_each_entry(tr, &blktrans_majors, list) 507 list_for_each_entry_safe(dev, next, &tr->devs, list) 508 if (dev->mtd == mtd) 509 tr->remove_dev(dev); 510 } 511 512 static void blktrans_notify_add(struct mtd_info *mtd) 513 { 514 struct mtd_blktrans_ops *tr; 515 516 if (mtd->type == MTD_ABSENT) 517 return; 518 519 list_for_each_entry(tr, &blktrans_majors, list) 520 tr->add_mtd(tr, mtd); 521 } 522 523 static struct mtd_notifier blktrans_notifier = { 524 .add = blktrans_notify_add, 525 .remove = blktrans_notify_remove, 526 }; 527 528 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 529 { 530 struct mtd_info *mtd; 531 int ret; 532 533 /* Register the notifier if/when the first device type is 534 registered, to prevent the link/init ordering from fucking 535 us over. */ 536 if (!blktrans_notifier.list.next) 537 register_mtd_user(&blktrans_notifier); 538 539 540 mutex_lock(&mtd_table_mutex); 541 542 ret = register_blkdev(tr->major, tr->name); 543 if (ret < 0) { 544 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 545 tr->name, tr->major, ret); 546 mutex_unlock(&mtd_table_mutex); 547 return ret; 548 } 549 550 if (ret) 551 tr->major = ret; 552 553 tr->blkshift = ffs(tr->blksize) - 1; 554 555 INIT_LIST_HEAD(&tr->devs); 556 list_add(&tr->list, &blktrans_majors); 557 558 mtd_for_each_device(mtd) 559 if (mtd->type != MTD_ABSENT) 560 tr->add_mtd(tr, mtd); 561 562 mutex_unlock(&mtd_table_mutex); 563 return 0; 564 } 565 566 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 567 { 568 struct mtd_blktrans_dev *dev, *next; 569 570 mutex_lock(&mtd_table_mutex); 571 572 /* Remove it from the list of active majors */ 573 list_del(&tr->list); 574 575 list_for_each_entry_safe(dev, next, &tr->devs, list) 576 tr->remove_dev(dev); 577 578 unregister_blkdev(tr->major, tr->name); 579 mutex_unlock(&mtd_table_mutex); 580 581 BUG_ON(!list_empty(&tr->devs)); 582 return 0; 583 } 584 585 static void __exit mtd_blktrans_exit(void) 586 { 587 /* No race here -- if someone's currently in register_mtd_blktrans 588 we're screwed anyway. */ 589 if (blktrans_notifier.list.next) 590 unregister_mtd_user(&blktrans_notifier); 591 } 592 593 module_exit(mtd_blktrans_exit); 594 595 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 596 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 597 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 598 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 599 600 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 601 MODULE_LICENSE("GPL"); 602 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 603