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 switch(rq_data_dir(req)) { 101 case READ: 102 for (; nsect > 0; nsect--, block++, buf += tr->blksize) 103 if (tr->readsect(dev, block, buf)) 104 return -EIO; 105 rq_flush_dcache_pages(req); 106 return 0; 107 case WRITE: 108 if (!tr->writesect) 109 return -EIO; 110 111 rq_flush_dcache_pages(req); 112 for (; nsect > 0; nsect--, block++, buf += tr->blksize) 113 if (tr->writesect(dev, block, buf)) 114 return -EIO; 115 return 0; 116 default: 117 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req)); 118 return -EIO; 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 int 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 if (req) 175 __blk_end_request_all(req, -EIO); 176 177 spin_unlock_irq(rq->queue_lock); 178 } 179 180 static void mtd_blktrans_request(struct request_queue *rq) 181 { 182 struct mtd_blktrans_dev *dev; 183 struct request *req = NULL; 184 185 dev = rq->queuedata; 186 187 if (!dev) 188 while ((req = blk_fetch_request(rq)) != NULL) 189 __blk_end_request_all(req, -ENODEV); 190 else 191 queue_work(dev->wq, &dev->work); 192 } 193 194 static int blktrans_open(struct block_device *bdev, fmode_t mode) 195 { 196 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 197 int ret = 0; 198 199 if (!dev) 200 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 201 202 mutex_lock(&dev->lock); 203 204 if (dev->open) 205 goto unlock; 206 207 kref_get(&dev->ref); 208 __module_get(dev->tr->owner); 209 210 if (!dev->mtd) 211 goto unlock; 212 213 if (dev->tr->open) { 214 ret = dev->tr->open(dev); 215 if (ret) 216 goto error_put; 217 } 218 219 ret = __get_mtd_device(dev->mtd); 220 if (ret) 221 goto error_release; 222 dev->file_mode = mode; 223 224 unlock: 225 dev->open++; 226 mutex_unlock(&dev->lock); 227 blktrans_dev_put(dev); 228 return ret; 229 230 error_release: 231 if (dev->tr->release) 232 dev->tr->release(dev); 233 error_put: 234 module_put(dev->tr->owner); 235 kref_put(&dev->ref, blktrans_dev_release); 236 mutex_unlock(&dev->lock); 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(&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 blktrans_dev_put(dev); 264 } 265 266 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 267 { 268 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 269 int ret = -ENXIO; 270 271 if (!dev) 272 return ret; 273 274 mutex_lock(&dev->lock); 275 276 if (!dev->mtd) 277 goto unlock; 278 279 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; 280 unlock: 281 mutex_unlock(&dev->lock); 282 blktrans_dev_put(dev); 283 return ret; 284 } 285 286 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 287 unsigned int cmd, unsigned long arg) 288 { 289 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 290 int ret = -ENXIO; 291 292 if (!dev) 293 return ret; 294 295 mutex_lock(&dev->lock); 296 297 if (!dev->mtd) 298 goto unlock; 299 300 switch (cmd) { 301 case BLKFLSBUF: 302 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 303 break; 304 default: 305 ret = -ENOTTY; 306 } 307 unlock: 308 mutex_unlock(&dev->lock); 309 blktrans_dev_put(dev); 310 return ret; 311 } 312 313 static const struct block_device_operations mtd_block_ops = { 314 .owner = THIS_MODULE, 315 .open = blktrans_open, 316 .release = blktrans_release, 317 .ioctl = blktrans_ioctl, 318 .getgeo = blktrans_getgeo, 319 }; 320 321 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 322 { 323 struct mtd_blktrans_ops *tr = new->tr; 324 struct mtd_blktrans_dev *d; 325 int last_devnum = -1; 326 struct gendisk *gd; 327 int ret; 328 329 if (mutex_trylock(&mtd_table_mutex)) { 330 mutex_unlock(&mtd_table_mutex); 331 BUG(); 332 } 333 334 mutex_lock(&blktrans_ref_mutex); 335 list_for_each_entry(d, &tr->devs, list) { 336 if (new->devnum == -1) { 337 /* Use first free number */ 338 if (d->devnum != last_devnum+1) { 339 /* Found a free devnum. Plug it in here */ 340 new->devnum = last_devnum+1; 341 list_add_tail(&new->list, &d->list); 342 goto added; 343 } 344 } else if (d->devnum == new->devnum) { 345 /* Required number taken */ 346 mutex_unlock(&blktrans_ref_mutex); 347 return -EBUSY; 348 } else if (d->devnum > new->devnum) { 349 /* Required number was free */ 350 list_add_tail(&new->list, &d->list); 351 goto added; 352 } 353 last_devnum = d->devnum; 354 } 355 356 ret = -EBUSY; 357 if (new->devnum == -1) 358 new->devnum = last_devnum+1; 359 360 /* Check that the device and any partitions will get valid 361 * minor numbers and that the disk naming code below can cope 362 * with this number. */ 363 if (new->devnum > (MINORMASK >> tr->part_bits) || 364 (tr->part_bits && new->devnum >= 27 * 26)) { 365 mutex_unlock(&blktrans_ref_mutex); 366 goto error1; 367 } 368 369 list_add_tail(&new->list, &tr->devs); 370 added: 371 mutex_unlock(&blktrans_ref_mutex); 372 373 mutex_init(&new->lock); 374 kref_init(&new->ref); 375 if (!tr->writesect) 376 new->readonly = 1; 377 378 /* Create gendisk */ 379 ret = -ENOMEM; 380 gd = alloc_disk(1 << tr->part_bits); 381 382 if (!gd) 383 goto error2; 384 385 new->disk = gd; 386 gd->private_data = new; 387 gd->major = tr->major; 388 gd->first_minor = (new->devnum) << tr->part_bits; 389 gd->fops = &mtd_block_ops; 390 391 if (tr->part_bits) 392 if (new->devnum < 26) 393 snprintf(gd->disk_name, sizeof(gd->disk_name), 394 "%s%c", tr->name, 'a' + new->devnum); 395 else 396 snprintf(gd->disk_name, sizeof(gd->disk_name), 397 "%s%c%c", tr->name, 398 'a' - 1 + new->devnum / 26, 399 'a' + new->devnum % 26); 400 else 401 snprintf(gd->disk_name, sizeof(gd->disk_name), 402 "%s%d", tr->name, new->devnum); 403 404 set_capacity(gd, (new->size * tr->blksize) >> 9); 405 406 /* Create the request queue */ 407 spin_lock_init(&new->queue_lock); 408 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 409 410 if (!new->rq) 411 goto error3; 412 413 if (tr->flush) 414 blk_queue_flush(new->rq, REQ_FLUSH); 415 416 new->rq->queuedata = new; 417 blk_queue_logical_block_size(new->rq, tr->blksize); 418 419 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); 420 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq); 421 422 if (tr->discard) { 423 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 424 new->rq->limits.max_discard_sectors = UINT_MAX; 425 } 426 427 gd->queue = new->rq; 428 429 /* Create processing workqueue */ 430 new->wq = alloc_workqueue("%s%d", 0, 0, 431 tr->name, new->mtd->index); 432 if (!new->wq) 433 goto error4; 434 INIT_WORK(&new->work, mtd_blktrans_work); 435 436 gd->driverfs_dev = &new->mtd->dev; 437 438 if (new->readonly) 439 set_disk_ro(gd, 1); 440 441 add_disk(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