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 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, -ENODEV); 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(&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 blktrans_dev_put(dev); 225 return ret; 226 227 error_release: 228 if (dev->tr->release) 229 dev->tr->release(dev); 230 error_put: 231 module_put(dev->tr->owner); 232 kref_put(&dev->ref, blktrans_dev_release); 233 mutex_unlock(&dev->lock); 234 blktrans_dev_put(dev); 235 return ret; 236 } 237 238 static void blktrans_release(struct gendisk *disk, fmode_t mode) 239 { 240 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 241 242 if (!dev) 243 return; 244 245 mutex_lock(&dev->lock); 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(&dev->lock); 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) : 0; 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, (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_flush(new->rq, REQ_FLUSH); 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 new->rq->limits.max_discard_sectors = 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 gd->driverfs_dev = &new->mtd->dev; 434 435 if (new->readonly) 436 set_disk_ro(gd, 1); 437 438 add_disk(gd); 439 440 if (new->disk_attributes) { 441 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 442 new->disk_attributes); 443 WARN_ON(ret); 444 } 445 return 0; 446 error4: 447 blk_cleanup_queue(new->rq); 448 error3: 449 put_disk(new->disk); 450 error2: 451 list_del(&new->list); 452 error1: 453 return ret; 454 } 455 456 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 457 { 458 unsigned long flags; 459 460 if (mutex_trylock(&mtd_table_mutex)) { 461 mutex_unlock(&mtd_table_mutex); 462 BUG(); 463 } 464 465 if (old->disk_attributes) 466 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 467 old->disk_attributes); 468 469 /* Stop new requests to arrive */ 470 del_gendisk(old->disk); 471 472 /* Stop workqueue. This will perform any pending request. */ 473 destroy_workqueue(old->wq); 474 475 /* Kill current requests */ 476 spin_lock_irqsave(&old->queue_lock, flags); 477 old->rq->queuedata = NULL; 478 blk_start_queue(old->rq); 479 spin_unlock_irqrestore(&old->queue_lock, flags); 480 481 /* If the device is currently open, tell trans driver to close it, 482 then put mtd device, and don't touch it again */ 483 mutex_lock(&old->lock); 484 if (old->open) { 485 if (old->tr->release) 486 old->tr->release(old); 487 __put_mtd_device(old->mtd); 488 } 489 490 old->mtd = NULL; 491 492 mutex_unlock(&old->lock); 493 blktrans_dev_put(old); 494 return 0; 495 } 496 497 static void blktrans_notify_remove(struct mtd_info *mtd) 498 { 499 struct mtd_blktrans_ops *tr; 500 struct mtd_blktrans_dev *dev, *next; 501 502 list_for_each_entry(tr, &blktrans_majors, list) 503 list_for_each_entry_safe(dev, next, &tr->devs, list) 504 if (dev->mtd == mtd) 505 tr->remove_dev(dev); 506 } 507 508 static void blktrans_notify_add(struct mtd_info *mtd) 509 { 510 struct mtd_blktrans_ops *tr; 511 512 if (mtd->type == MTD_ABSENT) 513 return; 514 515 list_for_each_entry(tr, &blktrans_majors, list) 516 tr->add_mtd(tr, mtd); 517 } 518 519 static struct mtd_notifier blktrans_notifier = { 520 .add = blktrans_notify_add, 521 .remove = blktrans_notify_remove, 522 }; 523 524 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 525 { 526 struct mtd_info *mtd; 527 int ret; 528 529 /* Register the notifier if/when the first device type is 530 registered, to prevent the link/init ordering from fucking 531 us over. */ 532 if (!blktrans_notifier.list.next) 533 register_mtd_user(&blktrans_notifier); 534 535 536 mutex_lock(&mtd_table_mutex); 537 538 ret = register_blkdev(tr->major, tr->name); 539 if (ret < 0) { 540 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 541 tr->name, tr->major, ret); 542 mutex_unlock(&mtd_table_mutex); 543 return ret; 544 } 545 546 if (ret) 547 tr->major = ret; 548 549 tr->blkshift = ffs(tr->blksize) - 1; 550 551 INIT_LIST_HEAD(&tr->devs); 552 list_add(&tr->list, &blktrans_majors); 553 554 mtd_for_each_device(mtd) 555 if (mtd->type != MTD_ABSENT) 556 tr->add_mtd(tr, mtd); 557 558 mutex_unlock(&mtd_table_mutex); 559 return 0; 560 } 561 562 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 563 { 564 struct mtd_blktrans_dev *dev, *next; 565 566 mutex_lock(&mtd_table_mutex); 567 568 /* Remove it from the list of active majors */ 569 list_del(&tr->list); 570 571 list_for_each_entry_safe(dev, next, &tr->devs, list) 572 tr->remove_dev(dev); 573 574 unregister_blkdev(tr->major, tr->name); 575 mutex_unlock(&mtd_table_mutex); 576 577 BUG_ON(!list_empty(&tr->devs)); 578 return 0; 579 } 580 581 static void __exit mtd_blktrans_exit(void) 582 { 583 /* No race here -- if someone's currently in register_mtd_blktrans 584 we're screwed anyway. */ 585 if (blktrans_notifier.list.next) 586 unregister_mtd_user(&blktrans_notifier); 587 } 588 589 module_exit(mtd_blktrans_exit); 590 591 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 592 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 593 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 594 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 595 596 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 597 MODULE_LICENSE("GPL"); 598 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 599