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 void blktrans_release(struct gendisk *disk, fmode_t mode) 241 { 242 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 243 244 if (!dev) 245 return; 246 247 mutex_lock(&dev->lock); 248 249 if (--dev->open) 250 goto unlock; 251 252 kref_put(&dev->ref, blktrans_dev_release); 253 module_put(dev->tr->owner); 254 255 if (dev->mtd) { 256 if (dev->tr->release) 257 dev->tr->release(dev); 258 __put_mtd_device(dev->mtd); 259 } 260 unlock: 261 mutex_unlock(&dev->lock); 262 blktrans_dev_put(dev); 263 } 264 265 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 266 { 267 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 268 int ret = -ENXIO; 269 270 if (!dev) 271 return ret; 272 273 mutex_lock(&dev->lock); 274 275 if (!dev->mtd) 276 goto unlock; 277 278 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; 279 unlock: 280 mutex_unlock(&dev->lock); 281 blktrans_dev_put(dev); 282 return ret; 283 } 284 285 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 286 unsigned int cmd, unsigned long arg) 287 { 288 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 289 int ret = -ENXIO; 290 291 if (!dev) 292 return ret; 293 294 mutex_lock(&dev->lock); 295 296 if (!dev->mtd) 297 goto unlock; 298 299 switch (cmd) { 300 case BLKFLSBUF: 301 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 302 break; 303 default: 304 ret = -ENOTTY; 305 } 306 unlock: 307 mutex_unlock(&dev->lock); 308 blktrans_dev_put(dev); 309 return ret; 310 } 311 312 static const struct block_device_operations mtd_block_ops = { 313 .owner = THIS_MODULE, 314 .open = blktrans_open, 315 .release = blktrans_release, 316 .ioctl = blktrans_ioctl, 317 .getgeo = blktrans_getgeo, 318 }; 319 320 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 321 { 322 struct mtd_blktrans_ops *tr = new->tr; 323 struct mtd_blktrans_dev *d; 324 int last_devnum = -1; 325 struct gendisk *gd; 326 int ret; 327 328 if (mutex_trylock(&mtd_table_mutex)) { 329 mutex_unlock(&mtd_table_mutex); 330 BUG(); 331 } 332 333 mutex_lock(&blktrans_ref_mutex); 334 list_for_each_entry(d, &tr->devs, list) { 335 if (new->devnum == -1) { 336 /* Use first free number */ 337 if (d->devnum != last_devnum+1) { 338 /* Found a free devnum. Plug it in here */ 339 new->devnum = last_devnum+1; 340 list_add_tail(&new->list, &d->list); 341 goto added; 342 } 343 } else if (d->devnum == new->devnum) { 344 /* Required number taken */ 345 mutex_unlock(&blktrans_ref_mutex); 346 return -EBUSY; 347 } else if (d->devnum > new->devnum) { 348 /* Required number was free */ 349 list_add_tail(&new->list, &d->list); 350 goto added; 351 } 352 last_devnum = d->devnum; 353 } 354 355 ret = -EBUSY; 356 if (new->devnum == -1) 357 new->devnum = last_devnum+1; 358 359 /* Check that the device and any partitions will get valid 360 * minor numbers and that the disk naming code below can cope 361 * with this number. */ 362 if (new->devnum > (MINORMASK >> tr->part_bits) || 363 (tr->part_bits && new->devnum >= 27 * 26)) { 364 mutex_unlock(&blktrans_ref_mutex); 365 goto error1; 366 } 367 368 list_add_tail(&new->list, &tr->devs); 369 added: 370 mutex_unlock(&blktrans_ref_mutex); 371 372 mutex_init(&new->lock); 373 kref_init(&new->ref); 374 if (!tr->writesect) 375 new->readonly = 1; 376 377 /* Create gendisk */ 378 ret = -ENOMEM; 379 gd = alloc_disk(1 << tr->part_bits); 380 381 if (!gd) 382 goto error2; 383 384 new->disk = gd; 385 gd->private_data = new; 386 gd->major = tr->major; 387 gd->first_minor = (new->devnum) << tr->part_bits; 388 gd->fops = &mtd_block_ops; 389 390 if (tr->part_bits) 391 if (new->devnum < 26) 392 snprintf(gd->disk_name, sizeof(gd->disk_name), 393 "%s%c", tr->name, 'a' + new->devnum); 394 else 395 snprintf(gd->disk_name, sizeof(gd->disk_name), 396 "%s%c%c", tr->name, 397 'a' - 1 + new->devnum / 26, 398 'a' + new->devnum % 26); 399 else 400 snprintf(gd->disk_name, sizeof(gd->disk_name), 401 "%s%d", tr->name, new->devnum); 402 403 set_capacity(gd, (new->size * tr->blksize) >> 9); 404 405 /* Create the request queue */ 406 spin_lock_init(&new->queue_lock); 407 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 408 409 if (!new->rq) 410 goto error3; 411 412 new->rq->queuedata = new; 413 blk_queue_logical_block_size(new->rq, tr->blksize); 414 415 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); 416 417 if (tr->discard) { 418 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 419 new->rq->limits.max_discard_sectors = UINT_MAX; 420 } 421 422 gd->queue = new->rq; 423 424 /* Create processing workqueue */ 425 new->wq = alloc_workqueue("%s%d", 0, 0, 426 tr->name, new->mtd->index); 427 if (!new->wq) 428 goto error4; 429 INIT_WORK(&new->work, mtd_blktrans_work); 430 431 gd->driverfs_dev = &new->mtd->dev; 432 433 if (new->readonly) 434 set_disk_ro(gd, 1); 435 436 add_disk(gd); 437 438 if (new->disk_attributes) { 439 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 440 new->disk_attributes); 441 WARN_ON(ret); 442 } 443 return 0; 444 error4: 445 blk_cleanup_queue(new->rq); 446 error3: 447 put_disk(new->disk); 448 error2: 449 list_del(&new->list); 450 error1: 451 return ret; 452 } 453 454 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 455 { 456 unsigned long flags; 457 458 if (mutex_trylock(&mtd_table_mutex)) { 459 mutex_unlock(&mtd_table_mutex); 460 BUG(); 461 } 462 463 if (old->disk_attributes) 464 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 465 old->disk_attributes); 466 467 /* Stop new requests to arrive */ 468 del_gendisk(old->disk); 469 470 /* Stop workqueue. This will perform any pending request. */ 471 destroy_workqueue(old->wq); 472 473 /* Kill current requests */ 474 spin_lock_irqsave(&old->queue_lock, flags); 475 old->rq->queuedata = NULL; 476 blk_start_queue(old->rq); 477 spin_unlock_irqrestore(&old->queue_lock, flags); 478 479 /* If the device is currently open, tell trans driver to close it, 480 then put mtd device, and don't touch it again */ 481 mutex_lock(&old->lock); 482 if (old->open) { 483 if (old->tr->release) 484 old->tr->release(old); 485 __put_mtd_device(old->mtd); 486 } 487 488 old->mtd = NULL; 489 490 mutex_unlock(&old->lock); 491 blktrans_dev_put(old); 492 return 0; 493 } 494 495 static void blktrans_notify_remove(struct mtd_info *mtd) 496 { 497 struct mtd_blktrans_ops *tr; 498 struct mtd_blktrans_dev *dev, *next; 499 500 list_for_each_entry(tr, &blktrans_majors, list) 501 list_for_each_entry_safe(dev, next, &tr->devs, list) 502 if (dev->mtd == mtd) 503 tr->remove_dev(dev); 504 } 505 506 static void blktrans_notify_add(struct mtd_info *mtd) 507 { 508 struct mtd_blktrans_ops *tr; 509 510 if (mtd->type == MTD_ABSENT) 511 return; 512 513 list_for_each_entry(tr, &blktrans_majors, list) 514 tr->add_mtd(tr, mtd); 515 } 516 517 static struct mtd_notifier blktrans_notifier = { 518 .add = blktrans_notify_add, 519 .remove = blktrans_notify_remove, 520 }; 521 522 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 523 { 524 struct mtd_info *mtd; 525 int ret; 526 527 /* Register the notifier if/when the first device type is 528 registered, to prevent the link/init ordering from fucking 529 us over. */ 530 if (!blktrans_notifier.list.next) 531 register_mtd_user(&blktrans_notifier); 532 533 534 mutex_lock(&mtd_table_mutex); 535 536 ret = register_blkdev(tr->major, tr->name); 537 if (ret < 0) { 538 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 539 tr->name, tr->major, ret); 540 mutex_unlock(&mtd_table_mutex); 541 return ret; 542 } 543 544 if (ret) 545 tr->major = ret; 546 547 tr->blkshift = ffs(tr->blksize) - 1; 548 549 INIT_LIST_HEAD(&tr->devs); 550 list_add(&tr->list, &blktrans_majors); 551 552 mtd_for_each_device(mtd) 553 if (mtd->type != MTD_ABSENT) 554 tr->add_mtd(tr, mtd); 555 556 mutex_unlock(&mtd_table_mutex); 557 return 0; 558 } 559 560 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 561 { 562 struct mtd_blktrans_dev *dev, *next; 563 564 mutex_lock(&mtd_table_mutex); 565 566 /* Remove it from the list of active majors */ 567 list_del(&tr->list); 568 569 list_for_each_entry_safe(dev, next, &tr->devs, list) 570 tr->remove_dev(dev); 571 572 unregister_blkdev(tr->major, tr->name); 573 mutex_unlock(&mtd_table_mutex); 574 575 BUG_ON(!list_empty(&tr->devs)); 576 return 0; 577 } 578 579 static void __exit mtd_blktrans_exit(void) 580 { 581 /* No race here -- if someone's currently in register_mtd_blktrans 582 we're screwed anyway. */ 583 if (blktrans_notifier.list.next) 584 unregister_mtd_user(&blktrans_notifier); 585 } 586 587 module_exit(mtd_blktrans_exit); 588 589 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 590 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 591 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 592 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 593 594 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 595 MODULE_LICENSE("GPL"); 596 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 597