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/init.h> 34 #include <linux/mutex.h> 35 #include <asm/uaccess.h> 36 37 #include "mtdcore.h" 38 39 static LIST_HEAD(blktrans_majors); 40 static DEFINE_MUTEX(blktrans_ref_mutex); 41 42 static void blktrans_dev_release(struct kref *kref) 43 { 44 struct mtd_blktrans_dev *dev = 45 container_of(kref, struct mtd_blktrans_dev, ref); 46 47 dev->disk->private_data = NULL; 48 blk_cleanup_queue(dev->rq); 49 put_disk(dev->disk); 50 list_del(&dev->list); 51 kfree(dev); 52 } 53 54 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk) 55 { 56 struct mtd_blktrans_dev *dev; 57 58 mutex_lock(&blktrans_ref_mutex); 59 dev = disk->private_data; 60 61 if (!dev) 62 goto unlock; 63 kref_get(&dev->ref); 64 unlock: 65 mutex_unlock(&blktrans_ref_mutex); 66 return dev; 67 } 68 69 static void blktrans_dev_put(struct mtd_blktrans_dev *dev) 70 { 71 mutex_lock(&blktrans_ref_mutex); 72 kref_put(&dev->ref, blktrans_dev_release); 73 mutex_unlock(&blktrans_ref_mutex); 74 } 75 76 77 static int do_blktrans_request(struct mtd_blktrans_ops *tr, 78 struct mtd_blktrans_dev *dev, 79 struct request *req) 80 { 81 unsigned long block, nsect; 82 char *buf; 83 84 block = blk_rq_pos(req) << 9 >> tr->blkshift; 85 nsect = blk_rq_cur_bytes(req) >> tr->blkshift; 86 87 buf = req->buffer; 88 89 if (req->cmd_type != REQ_TYPE_FS) 90 return -EIO; 91 92 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > 93 get_capacity(req->rq_disk)) 94 return -EIO; 95 96 if (req->cmd_flags & REQ_DISCARD) 97 return tr->discard(dev, block, nsect); 98 99 switch(rq_data_dir(req)) { 100 case READ: 101 for (; nsect > 0; nsect--, block++, buf += tr->blksize) 102 if (tr->readsect(dev, block, buf)) 103 return -EIO; 104 rq_flush_dcache_pages(req); 105 return 0; 106 case WRITE: 107 if (!tr->writesect) 108 return -EIO; 109 110 rq_flush_dcache_pages(req); 111 for (; nsect > 0; nsect--, block++, buf += tr->blksize) 112 if (tr->writesect(dev, block, buf)) 113 return -EIO; 114 return 0; 115 default: 116 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req)); 117 return -EIO; 118 } 119 } 120 121 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) 122 { 123 return dev->bg_stop; 124 } 125 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); 126 127 static void mtd_blktrans_work(struct work_struct *work) 128 { 129 struct mtd_blktrans_dev *dev = 130 container_of(work, struct mtd_blktrans_dev, work); 131 struct mtd_blktrans_ops *tr = dev->tr; 132 struct request_queue *rq = dev->rq; 133 struct request *req = NULL; 134 int background_done = 0; 135 136 spin_lock_irq(rq->queue_lock); 137 138 while (1) { 139 int res; 140 141 dev->bg_stop = false; 142 if (!req && !(req = blk_fetch_request(rq))) { 143 if (tr->background && !background_done) { 144 spin_unlock_irq(rq->queue_lock); 145 mutex_lock(&dev->lock); 146 tr->background(dev); 147 mutex_unlock(&dev->lock); 148 spin_lock_irq(rq->queue_lock); 149 /* 150 * Do background processing just once per idle 151 * period. 152 */ 153 background_done = !dev->bg_stop; 154 continue; 155 } 156 break; 157 } 158 159 spin_unlock_irq(rq->queue_lock); 160 161 mutex_lock(&dev->lock); 162 res = do_blktrans_request(dev->tr, dev, req); 163 mutex_unlock(&dev->lock); 164 165 spin_lock_irq(rq->queue_lock); 166 167 if (!__blk_end_request_cur(req, res)) 168 req = NULL; 169 170 background_done = 0; 171 } 172 173 if (req) 174 __blk_end_request_all(req, -EIO); 175 176 spin_unlock_irq(rq->queue_lock); 177 } 178 179 static void mtd_blktrans_request(struct request_queue *rq) 180 { 181 struct mtd_blktrans_dev *dev; 182 struct request *req = NULL; 183 184 dev = rq->queuedata; 185 186 if (!dev) 187 while ((req = blk_fetch_request(rq)) != NULL) 188 __blk_end_request_all(req, -ENODEV); 189 else 190 queue_work(dev->wq, &dev->work); 191 } 192 193 static int blktrans_open(struct block_device *bdev, fmode_t mode) 194 { 195 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 196 int ret = 0; 197 198 if (!dev) 199 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 200 201 mutex_lock(&dev->lock); 202 203 if (dev->open) 204 goto unlock; 205 206 kref_get(&dev->ref); 207 __module_get(dev->tr->owner); 208 209 if (!dev->mtd) 210 goto unlock; 211 212 if (dev->tr->open) { 213 ret = dev->tr->open(dev); 214 if (ret) 215 goto error_put; 216 } 217 218 ret = __get_mtd_device(dev->mtd); 219 if (ret) 220 goto error_release; 221 dev->file_mode = mode; 222 223 unlock: 224 dev->open++; 225 mutex_unlock(&dev->lock); 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 blktrans_dev_put(dev); 237 return ret; 238 } 239 240 static int blktrans_release(struct gendisk *disk, fmode_t mode) 241 { 242 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 243 int ret = 0; 244 245 if (!dev) 246 return ret; 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 ret = dev->tr->release ? dev->tr->release(dev) : 0; 258 __put_mtd_device(dev->mtd); 259 } 260 unlock: 261 mutex_unlock(&dev->lock); 262 blktrans_dev_put(dev); 263 return ret; 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 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); 417 418 if (tr->discard) { 419 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 420 new->rq->limits.max_discard_sectors = UINT_MAX; 421 } 422 423 gd->queue = new->rq; 424 425 /* Create processing workqueue */ 426 new->wq = alloc_workqueue("%s%d", 0, 0, 427 tr->name, new->mtd->index); 428 if (!new->wq) 429 goto error4; 430 INIT_WORK(&new->work, mtd_blktrans_work); 431 432 gd->driverfs_dev = &new->mtd->dev; 433 434 if (new->readonly) 435 set_disk_ro(gd, 1); 436 437 add_disk(gd); 438 439 if (new->disk_attributes) { 440 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 441 new->disk_attributes); 442 WARN_ON(ret); 443 } 444 return 0; 445 error4: 446 blk_cleanup_queue(new->rq); 447 error3: 448 put_disk(new->disk); 449 error2: 450 list_del(&new->list); 451 error1: 452 return ret; 453 } 454 455 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 456 { 457 unsigned long flags; 458 459 if (mutex_trylock(&mtd_table_mutex)) { 460 mutex_unlock(&mtd_table_mutex); 461 BUG(); 462 } 463 464 if (old->disk_attributes) 465 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 466 old->disk_attributes); 467 468 /* Stop new requests to arrive */ 469 del_gendisk(old->disk); 470 471 /* Stop workqueue. This will perform any pending request. */ 472 destroy_workqueue(old->wq); 473 474 /* Kill current requests */ 475 spin_lock_irqsave(&old->queue_lock, flags); 476 old->rq->queuedata = NULL; 477 blk_start_queue(old->rq); 478 spin_unlock_irqrestore(&old->queue_lock, flags); 479 480 /* If the device is currently open, tell trans driver to close it, 481 then put mtd device, and don't touch it again */ 482 mutex_lock(&old->lock); 483 if (old->open) { 484 if (old->tr->release) 485 old->tr->release(old); 486 __put_mtd_device(old->mtd); 487 } 488 489 old->mtd = NULL; 490 491 mutex_unlock(&old->lock); 492 blktrans_dev_put(old); 493 return 0; 494 } 495 496 static void blktrans_notify_remove(struct mtd_info *mtd) 497 { 498 struct mtd_blktrans_ops *tr; 499 struct mtd_blktrans_dev *dev, *next; 500 501 list_for_each_entry(tr, &blktrans_majors, list) 502 list_for_each_entry_safe(dev, next, &tr->devs, list) 503 if (dev->mtd == mtd) 504 tr->remove_dev(dev); 505 } 506 507 static void blktrans_notify_add(struct mtd_info *mtd) 508 { 509 struct mtd_blktrans_ops *tr; 510 511 if (mtd->type == MTD_ABSENT) 512 return; 513 514 list_for_each_entry(tr, &blktrans_majors, list) 515 tr->add_mtd(tr, mtd); 516 } 517 518 static struct mtd_notifier blktrans_notifier = { 519 .add = blktrans_notify_add, 520 .remove = blktrans_notify_remove, 521 }; 522 523 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 524 { 525 struct mtd_info *mtd; 526 int ret; 527 528 /* Register the notifier if/when the first device type is 529 registered, to prevent the link/init ordering from fucking 530 us over. */ 531 if (!blktrans_notifier.list.next) 532 register_mtd_user(&blktrans_notifier); 533 534 535 mutex_lock(&mtd_table_mutex); 536 537 ret = register_blkdev(tr->major, tr->name); 538 if (ret < 0) { 539 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 540 tr->name, tr->major, ret); 541 mutex_unlock(&mtd_table_mutex); 542 return ret; 543 } 544 545 if (ret) 546 tr->major = ret; 547 548 tr->blkshift = ffs(tr->blksize) - 1; 549 550 INIT_LIST_HEAD(&tr->devs); 551 list_add(&tr->list, &blktrans_majors); 552 553 mtd_for_each_device(mtd) 554 if (mtd->type != MTD_ABSENT) 555 tr->add_mtd(tr, mtd); 556 557 mutex_unlock(&mtd_table_mutex); 558 return 0; 559 } 560 561 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 562 { 563 struct mtd_blktrans_dev *dev, *next; 564 565 mutex_lock(&mtd_table_mutex); 566 567 /* Remove it from the list of active majors */ 568 list_del(&tr->list); 569 570 list_for_each_entry_safe(dev, next, &tr->devs, list) 571 tr->remove_dev(dev); 572 573 unregister_blkdev(tr->major, tr->name); 574 mutex_unlock(&mtd_table_mutex); 575 576 BUG_ON(!list_empty(&tr->devs)); 577 return 0; 578 } 579 580 static void __exit mtd_blktrans_exit(void) 581 { 582 /* No race here -- if someone's currently in register_mtd_blktrans 583 we're screwed anyway. */ 584 if (blktrans_notifier.list.next) 585 unregister_mtd_user(&blktrans_notifier); 586 } 587 588 module_exit(mtd_blktrans_exit); 589 590 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 591 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 592 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 593 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 594 595 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 596 MODULE_LICENSE("GPL"); 597 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 598