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 86 buf = req->buffer; 87 88 if (req->cmd_type != REQ_TYPE_FS) 89 return -EIO; 90 91 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > 92 get_capacity(req->rq_disk)) 93 return -EIO; 94 95 if (req->cmd_flags & REQ_DISCARD) 96 return tr->discard(dev, block, nsect); 97 98 switch(rq_data_dir(req)) { 99 case READ: 100 for (; nsect > 0; nsect--, block++, buf += tr->blksize) 101 if (tr->readsect(dev, block, buf)) 102 return -EIO; 103 rq_flush_dcache_pages(req); 104 return 0; 105 case WRITE: 106 if (!tr->writesect) 107 return -EIO; 108 109 rq_flush_dcache_pages(req); 110 for (; nsect > 0; nsect--, block++, buf += tr->blksize) 111 if (tr->writesect(dev, block, buf)) 112 return -EIO; 113 return 0; 114 default: 115 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req)); 116 return -EIO; 117 } 118 } 119 120 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) 121 { 122 return dev->bg_stop; 123 } 124 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); 125 126 static void mtd_blktrans_work(struct work_struct *work) 127 { 128 struct mtd_blktrans_dev *dev = 129 container_of(work, struct mtd_blktrans_dev, work); 130 struct mtd_blktrans_ops *tr = dev->tr; 131 struct request_queue *rq = dev->rq; 132 struct request *req = NULL; 133 int background_done = 0; 134 135 spin_lock_irq(rq->queue_lock); 136 137 while (1) { 138 int res; 139 140 dev->bg_stop = false; 141 if (!req && !(req = blk_fetch_request(rq))) { 142 if (tr->background && !background_done) { 143 spin_unlock_irq(rq->queue_lock); 144 mutex_lock(&dev->lock); 145 tr->background(dev); 146 mutex_unlock(&dev->lock); 147 spin_lock_irq(rq->queue_lock); 148 /* 149 * Do background processing just once per idle 150 * period. 151 */ 152 background_done = !dev->bg_stop; 153 continue; 154 } 155 break; 156 } 157 158 spin_unlock_irq(rq->queue_lock); 159 160 mutex_lock(&dev->lock); 161 res = do_blktrans_request(dev->tr, dev, req); 162 mutex_unlock(&dev->lock); 163 164 spin_lock_irq(rq->queue_lock); 165 166 if (!__blk_end_request_cur(req, res)) 167 req = NULL; 168 169 background_done = 0; 170 } 171 172 if (req) 173 __blk_end_request_all(req, -EIO); 174 175 spin_unlock_irq(rq->queue_lock); 176 } 177 178 static void mtd_blktrans_request(struct request_queue *rq) 179 { 180 struct mtd_blktrans_dev *dev; 181 struct request *req = NULL; 182 183 dev = rq->queuedata; 184 185 if (!dev) 186 while ((req = blk_fetch_request(rq)) != NULL) 187 __blk_end_request_all(req, -ENODEV); 188 else 189 queue_work(dev->wq, &dev->work); 190 } 191 192 static int blktrans_open(struct block_device *bdev, fmode_t mode) 193 { 194 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 195 int ret = 0; 196 197 if (!dev) 198 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 199 200 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 blktrans_dev_put(dev); 226 return ret; 227 228 error_release: 229 if (dev->tr->release) 230 dev->tr->release(dev); 231 error_put: 232 module_put(dev->tr->owner); 233 kref_put(&dev->ref, blktrans_dev_release); 234 mutex_unlock(&dev->lock); 235 blktrans_dev_put(dev); 236 return ret; 237 } 238 239 static void blktrans_release(struct gendisk *disk, fmode_t mode) 240 { 241 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 242 243 if (!dev) 244 return; 245 246 mutex_lock(&dev->lock); 247 248 if (--dev->open) 249 goto unlock; 250 251 kref_put(&dev->ref, blktrans_dev_release); 252 module_put(dev->tr->owner); 253 254 if (dev->mtd) { 255 if (dev->tr->release) 256 dev->tr->release(dev); 257 __put_mtd_device(dev->mtd); 258 } 259 unlock: 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) : 0; 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 new->rq->queuedata = new; 412 blk_queue_logical_block_size(new->rq, tr->blksize); 413 414 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); 415 416 if (tr->discard) { 417 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 418 new->rq->limits.max_discard_sectors = UINT_MAX; 419 } 420 421 gd->queue = new->rq; 422 423 /* Create processing workqueue */ 424 new->wq = alloc_workqueue("%s%d", 0, 0, 425 tr->name, new->mtd->index); 426 if (!new->wq) 427 goto error4; 428 INIT_WORK(&new->work, mtd_blktrans_work); 429 430 gd->driverfs_dev = &new->mtd->dev; 431 432 if (new->readonly) 433 set_disk_ro(gd, 1); 434 435 add_disk(gd); 436 437 if (new->disk_attributes) { 438 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 439 new->disk_attributes); 440 WARN_ON(ret); 441 } 442 return 0; 443 error4: 444 blk_cleanup_queue(new->rq); 445 error3: 446 put_disk(new->disk); 447 error2: 448 list_del(&new->list); 449 error1: 450 return ret; 451 } 452 453 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 454 { 455 unsigned long flags; 456 457 if (mutex_trylock(&mtd_table_mutex)) { 458 mutex_unlock(&mtd_table_mutex); 459 BUG(); 460 } 461 462 if (old->disk_attributes) 463 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 464 old->disk_attributes); 465 466 /* Stop new requests to arrive */ 467 del_gendisk(old->disk); 468 469 /* Stop workqueue. This will perform any pending request. */ 470 destroy_workqueue(old->wq); 471 472 /* Kill current requests */ 473 spin_lock_irqsave(&old->queue_lock, flags); 474 old->rq->queuedata = NULL; 475 blk_start_queue(old->rq); 476 spin_unlock_irqrestore(&old->queue_lock, flags); 477 478 /* If the device is currently open, tell trans driver to close it, 479 then put mtd device, and don't touch it again */ 480 mutex_lock(&old->lock); 481 if (old->open) { 482 if (old->tr->release) 483 old->tr->release(old); 484 __put_mtd_device(old->mtd); 485 } 486 487 old->mtd = NULL; 488 489 mutex_unlock(&old->lock); 490 blktrans_dev_put(old); 491 return 0; 492 } 493 494 static void blktrans_notify_remove(struct mtd_info *mtd) 495 { 496 struct mtd_blktrans_ops *tr; 497 struct mtd_blktrans_dev *dev, *next; 498 499 list_for_each_entry(tr, &blktrans_majors, list) 500 list_for_each_entry_safe(dev, next, &tr->devs, list) 501 if (dev->mtd == mtd) 502 tr->remove_dev(dev); 503 } 504 505 static void blktrans_notify_add(struct mtd_info *mtd) 506 { 507 struct mtd_blktrans_ops *tr; 508 509 if (mtd->type == MTD_ABSENT) 510 return; 511 512 list_for_each_entry(tr, &blktrans_majors, list) 513 tr->add_mtd(tr, mtd); 514 } 515 516 static struct mtd_notifier blktrans_notifier = { 517 .add = blktrans_notify_add, 518 .remove = blktrans_notify_remove, 519 }; 520 521 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 522 { 523 struct mtd_info *mtd; 524 int ret; 525 526 /* Register the notifier if/when the first device type is 527 registered, to prevent the link/init ordering from fucking 528 us over. */ 529 if (!blktrans_notifier.list.next) 530 register_mtd_user(&blktrans_notifier); 531 532 533 mutex_lock(&mtd_table_mutex); 534 535 ret = register_blkdev(tr->major, tr->name); 536 if (ret < 0) { 537 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 538 tr->name, tr->major, ret); 539 mutex_unlock(&mtd_table_mutex); 540 return ret; 541 } 542 543 if (ret) 544 tr->major = ret; 545 546 tr->blkshift = ffs(tr->blksize) - 1; 547 548 INIT_LIST_HEAD(&tr->devs); 549 list_add(&tr->list, &blktrans_majors); 550 551 mtd_for_each_device(mtd) 552 if (mtd->type != MTD_ABSENT) 553 tr->add_mtd(tr, mtd); 554 555 mutex_unlock(&mtd_table_mutex); 556 return 0; 557 } 558 559 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 560 { 561 struct mtd_blktrans_dev *dev, *next; 562 563 mutex_lock(&mtd_table_mutex); 564 565 /* Remove it from the list of active majors */ 566 list_del(&tr->list); 567 568 list_for_each_entry_safe(dev, next, &tr->devs, list) 569 tr->remove_dev(dev); 570 571 unregister_blkdev(tr->major, tr->name); 572 mutex_unlock(&mtd_table_mutex); 573 574 BUG_ON(!list_empty(&tr->devs)); 575 return 0; 576 } 577 578 static void __exit mtd_blktrans_exit(void) 579 { 580 /* No race here -- if someone's currently in register_mtd_blktrans 581 we're screwed anyway. */ 582 if (blktrans_notifier.list.next) 583 unregister_mtd_user(&blktrans_notifier); 584 } 585 586 module_exit(mtd_blktrans_exit); 587 588 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 589 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 590 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 591 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 592 593 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 594 MODULE_LICENSE("GPL"); 595 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 596