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 <linux/kthread.h> 36 #include <asm/uaccess.h> 37 38 #include "mtdcore.h" 39 40 static LIST_HEAD(blktrans_majors); 41 static DEFINE_MUTEX(blktrans_ref_mutex); 42 43 static void blktrans_dev_release(struct kref *kref) 44 { 45 struct mtd_blktrans_dev *dev = 46 container_of(kref, struct mtd_blktrans_dev, ref); 47 48 dev->disk->private_data = NULL; 49 blk_cleanup_queue(dev->rq); 50 put_disk(dev->disk); 51 list_del(&dev->list); 52 kfree(dev); 53 } 54 55 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk) 56 { 57 struct mtd_blktrans_dev *dev; 58 59 mutex_lock(&blktrans_ref_mutex); 60 dev = disk->private_data; 61 62 if (!dev) 63 goto unlock; 64 kref_get(&dev->ref); 65 unlock: 66 mutex_unlock(&blktrans_ref_mutex); 67 return dev; 68 } 69 70 static void blktrans_dev_put(struct mtd_blktrans_dev *dev) 71 { 72 mutex_lock(&blktrans_ref_mutex); 73 kref_put(&dev->ref, blktrans_dev_release); 74 mutex_unlock(&blktrans_ref_mutex); 75 } 76 77 78 static int do_blktrans_request(struct mtd_blktrans_ops *tr, 79 struct mtd_blktrans_dev *dev, 80 struct request *req) 81 { 82 unsigned long block, nsect; 83 char *buf; 84 85 block = blk_rq_pos(req) << 9 >> tr->blkshift; 86 nsect = blk_rq_cur_bytes(req) >> tr->blkshift; 87 88 buf = req->buffer; 89 90 if (req->cmd_type != REQ_TYPE_FS) 91 return -EIO; 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 if (kthread_should_stop()) 125 return 1; 126 127 return dev->bg_stop; 128 } 129 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); 130 131 static int mtd_blktrans_thread(void *arg) 132 { 133 struct mtd_blktrans_dev *dev = arg; 134 struct mtd_blktrans_ops *tr = dev->tr; 135 struct request_queue *rq = dev->rq; 136 struct request *req = NULL; 137 int background_done = 0; 138 139 spin_lock_irq(rq->queue_lock); 140 141 while (!kthread_should_stop()) { 142 int res; 143 144 dev->bg_stop = false; 145 if (!req && !(req = blk_fetch_request(rq))) { 146 if (tr->background && !background_done) { 147 spin_unlock_irq(rq->queue_lock); 148 mutex_lock(&dev->lock); 149 tr->background(dev); 150 mutex_unlock(&dev->lock); 151 spin_lock_irq(rq->queue_lock); 152 /* 153 * Do background processing just once per idle 154 * period. 155 */ 156 background_done = !dev->bg_stop; 157 continue; 158 } 159 set_current_state(TASK_INTERRUPTIBLE); 160 161 if (kthread_should_stop()) 162 set_current_state(TASK_RUNNING); 163 164 spin_unlock_irq(rq->queue_lock); 165 schedule(); 166 spin_lock_irq(rq->queue_lock); 167 continue; 168 } 169 170 spin_unlock_irq(rq->queue_lock); 171 172 mutex_lock(&dev->lock); 173 res = do_blktrans_request(dev->tr, dev, req); 174 mutex_unlock(&dev->lock); 175 176 spin_lock_irq(rq->queue_lock); 177 178 if (!__blk_end_request_cur(req, res)) 179 req = NULL; 180 181 background_done = 0; 182 } 183 184 if (req) 185 __blk_end_request_all(req, -EIO); 186 187 spin_unlock_irq(rq->queue_lock); 188 189 return 0; 190 } 191 192 static void mtd_blktrans_request(struct request_queue *rq) 193 { 194 struct mtd_blktrans_dev *dev; 195 struct request *req = NULL; 196 197 dev = rq->queuedata; 198 199 if (!dev) 200 while ((req = blk_fetch_request(rq)) != NULL) 201 __blk_end_request_all(req, -ENODEV); 202 else { 203 dev->bg_stop = true; 204 wake_up_process(dev->thread); 205 } 206 } 207 208 static int blktrans_open(struct block_device *bdev, fmode_t mode) 209 { 210 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 211 int ret = 0; 212 213 if (!dev) 214 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 215 216 mutex_lock(&dev->lock); 217 218 if (dev->open++) 219 goto unlock; 220 221 kref_get(&dev->ref); 222 __module_get(dev->tr->owner); 223 224 if (!dev->mtd) 225 goto unlock; 226 227 if (dev->tr->open) { 228 ret = dev->tr->open(dev); 229 if (ret) 230 goto error_put; 231 } 232 233 ret = __get_mtd_device(dev->mtd); 234 if (ret) 235 goto error_release; 236 237 unlock: 238 mutex_unlock(&dev->lock); 239 blktrans_dev_put(dev); 240 return ret; 241 242 error_release: 243 if (dev->tr->release) 244 dev->tr->release(dev); 245 error_put: 246 module_put(dev->tr->owner); 247 kref_put(&dev->ref, blktrans_dev_release); 248 mutex_unlock(&dev->lock); 249 blktrans_dev_put(dev); 250 return ret; 251 } 252 253 static int blktrans_release(struct gendisk *disk, fmode_t mode) 254 { 255 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 256 int ret = 0; 257 258 if (!dev) 259 return ret; 260 261 mutex_lock(&dev->lock); 262 263 if (--dev->open) 264 goto unlock; 265 266 kref_put(&dev->ref, blktrans_dev_release); 267 module_put(dev->tr->owner); 268 269 if (dev->mtd) { 270 ret = dev->tr->release ? dev->tr->release(dev) : 0; 271 __put_mtd_device(dev->mtd); 272 } 273 unlock: 274 mutex_unlock(&dev->lock); 275 blktrans_dev_put(dev); 276 return ret; 277 } 278 279 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 280 { 281 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 282 int ret = -ENXIO; 283 284 if (!dev) 285 return ret; 286 287 mutex_lock(&dev->lock); 288 289 if (!dev->mtd) 290 goto unlock; 291 292 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; 293 unlock: 294 mutex_unlock(&dev->lock); 295 blktrans_dev_put(dev); 296 return ret; 297 } 298 299 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 300 unsigned int cmd, unsigned long arg) 301 { 302 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 303 int ret = -ENXIO; 304 305 if (!dev) 306 return ret; 307 308 mutex_lock(&dev->lock); 309 310 if (!dev->mtd) 311 goto unlock; 312 313 switch (cmd) { 314 case BLKFLSBUF: 315 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 316 break; 317 default: 318 ret = -ENOTTY; 319 } 320 unlock: 321 mutex_unlock(&dev->lock); 322 blktrans_dev_put(dev); 323 return ret; 324 } 325 326 static const struct block_device_operations mtd_blktrans_ops = { 327 .owner = THIS_MODULE, 328 .open = blktrans_open, 329 .release = blktrans_release, 330 .ioctl = blktrans_ioctl, 331 .getgeo = blktrans_getgeo, 332 }; 333 334 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 335 { 336 struct mtd_blktrans_ops *tr = new->tr; 337 struct mtd_blktrans_dev *d; 338 int last_devnum = -1; 339 struct gendisk *gd; 340 int ret; 341 342 if (mutex_trylock(&mtd_table_mutex)) { 343 mutex_unlock(&mtd_table_mutex); 344 BUG(); 345 } 346 347 mutex_lock(&blktrans_ref_mutex); 348 list_for_each_entry(d, &tr->devs, list) { 349 if (new->devnum == -1) { 350 /* Use first free number */ 351 if (d->devnum != last_devnum+1) { 352 /* Found a free devnum. Plug it in here */ 353 new->devnum = last_devnum+1; 354 list_add_tail(&new->list, &d->list); 355 goto added; 356 } 357 } else if (d->devnum == new->devnum) { 358 /* Required number taken */ 359 mutex_unlock(&blktrans_ref_mutex); 360 return -EBUSY; 361 } else if (d->devnum > new->devnum) { 362 /* Required number was free */ 363 list_add_tail(&new->list, &d->list); 364 goto added; 365 } 366 last_devnum = d->devnum; 367 } 368 369 ret = -EBUSY; 370 if (new->devnum == -1) 371 new->devnum = last_devnum+1; 372 373 /* Check that the device and any partitions will get valid 374 * minor numbers and that the disk naming code below can cope 375 * with this number. */ 376 if (new->devnum > (MINORMASK >> tr->part_bits) || 377 (tr->part_bits && new->devnum >= 27 * 26)) { 378 mutex_unlock(&blktrans_ref_mutex); 379 goto error1; 380 } 381 382 list_add_tail(&new->list, &tr->devs); 383 added: 384 mutex_unlock(&blktrans_ref_mutex); 385 386 mutex_init(&new->lock); 387 kref_init(&new->ref); 388 if (!tr->writesect) 389 new->readonly = 1; 390 391 /* Create gendisk */ 392 ret = -ENOMEM; 393 gd = alloc_disk(1 << tr->part_bits); 394 395 if (!gd) 396 goto error2; 397 398 new->disk = gd; 399 gd->private_data = new; 400 gd->major = tr->major; 401 gd->first_minor = (new->devnum) << tr->part_bits; 402 gd->fops = &mtd_blktrans_ops; 403 404 if (tr->part_bits) 405 if (new->devnum < 26) 406 snprintf(gd->disk_name, sizeof(gd->disk_name), 407 "%s%c", tr->name, 'a' + new->devnum); 408 else 409 snprintf(gd->disk_name, sizeof(gd->disk_name), 410 "%s%c%c", tr->name, 411 'a' - 1 + new->devnum / 26, 412 'a' + new->devnum % 26); 413 else 414 snprintf(gd->disk_name, sizeof(gd->disk_name), 415 "%s%d", tr->name, new->devnum); 416 417 set_capacity(gd, (new->size * tr->blksize) >> 9); 418 419 /* Create the request queue */ 420 spin_lock_init(&new->queue_lock); 421 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 422 423 if (!new->rq) 424 goto error3; 425 426 new->rq->queuedata = new; 427 blk_queue_logical_block_size(new->rq, tr->blksize); 428 429 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); 430 431 if (tr->discard) { 432 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 433 new->rq->limits.max_discard_sectors = UINT_MAX; 434 } 435 436 gd->queue = new->rq; 437 438 /* Create processing thread */ 439 /* TODO: workqueue ? */ 440 new->thread = kthread_run(mtd_blktrans_thread, new, 441 "%s%d", tr->name, new->mtd->index); 442 if (IS_ERR(new->thread)) { 443 ret = PTR_ERR(new->thread); 444 goto error4; 445 } 446 gd->driverfs_dev = &new->mtd->dev; 447 448 if (new->readonly) 449 set_disk_ro(gd, 1); 450 451 add_disk(gd); 452 453 if (new->disk_attributes) { 454 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 455 new->disk_attributes); 456 WARN_ON(ret); 457 } 458 return 0; 459 error4: 460 blk_cleanup_queue(new->rq); 461 error3: 462 put_disk(new->disk); 463 error2: 464 list_del(&new->list); 465 error1: 466 return ret; 467 } 468 469 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 470 { 471 unsigned long flags; 472 473 if (mutex_trylock(&mtd_table_mutex)) { 474 mutex_unlock(&mtd_table_mutex); 475 BUG(); 476 } 477 478 if (old->disk_attributes) 479 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 480 old->disk_attributes); 481 482 /* Stop new requests to arrive */ 483 del_gendisk(old->disk); 484 485 486 /* Stop the thread */ 487 kthread_stop(old->thread); 488 489 /* Kill current requests */ 490 spin_lock_irqsave(&old->queue_lock, flags); 491 old->rq->queuedata = NULL; 492 blk_start_queue(old->rq); 493 spin_unlock_irqrestore(&old->queue_lock, flags); 494 495 /* If the device is currently open, tell trans driver to close it, 496 then put mtd device, and don't touch it again */ 497 mutex_lock(&old->lock); 498 if (old->open) { 499 if (old->tr->release) 500 old->tr->release(old); 501 __put_mtd_device(old->mtd); 502 } 503 504 old->mtd = NULL; 505 506 mutex_unlock(&old->lock); 507 blktrans_dev_put(old); 508 return 0; 509 } 510 511 static void blktrans_notify_remove(struct mtd_info *mtd) 512 { 513 struct mtd_blktrans_ops *tr; 514 struct mtd_blktrans_dev *dev, *next; 515 516 list_for_each_entry(tr, &blktrans_majors, list) 517 list_for_each_entry_safe(dev, next, &tr->devs, list) 518 if (dev->mtd == mtd) 519 tr->remove_dev(dev); 520 } 521 522 static void blktrans_notify_add(struct mtd_info *mtd) 523 { 524 struct mtd_blktrans_ops *tr; 525 526 if (mtd->type == MTD_ABSENT) 527 return; 528 529 list_for_each_entry(tr, &blktrans_majors, list) 530 tr->add_mtd(tr, mtd); 531 } 532 533 static struct mtd_notifier blktrans_notifier = { 534 .add = blktrans_notify_add, 535 .remove = blktrans_notify_remove, 536 }; 537 538 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 539 { 540 struct mtd_info *mtd; 541 int ret; 542 543 /* Register the notifier if/when the first device type is 544 registered, to prevent the link/init ordering from fucking 545 us over. */ 546 if (!blktrans_notifier.list.next) 547 register_mtd_user(&blktrans_notifier); 548 549 550 mutex_lock(&mtd_table_mutex); 551 552 ret = register_blkdev(tr->major, tr->name); 553 if (ret < 0) { 554 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 555 tr->name, tr->major, ret); 556 mutex_unlock(&mtd_table_mutex); 557 return ret; 558 } 559 560 if (ret) 561 tr->major = ret; 562 563 tr->blkshift = ffs(tr->blksize) - 1; 564 565 INIT_LIST_HEAD(&tr->devs); 566 list_add(&tr->list, &blktrans_majors); 567 568 mtd_for_each_device(mtd) 569 if (mtd->type != MTD_ABSENT) 570 tr->add_mtd(tr, mtd); 571 572 mutex_unlock(&mtd_table_mutex); 573 return 0; 574 } 575 576 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 577 { 578 struct mtd_blktrans_dev *dev, *next; 579 580 mutex_lock(&mtd_table_mutex); 581 582 /* Remove it from the list of active majors */ 583 list_del(&tr->list); 584 585 list_for_each_entry_safe(dev, next, &tr->devs, list) 586 tr->remove_dev(dev); 587 588 unregister_blkdev(tr->major, tr->name); 589 mutex_unlock(&mtd_table_mutex); 590 591 BUG_ON(!list_empty(&tr->devs)); 592 return 0; 593 } 594 595 static void __exit mtd_blktrans_exit(void) 596 { 597 /* No race here -- if someone's currently in register_mtd_blktrans 598 we're screwed anyway. */ 599 if (blktrans_notifier.list.next) 600 unregister_mtd_user(&blktrans_notifier); 601 } 602 603 module_exit(mtd_blktrans_exit); 604 605 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 606 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 607 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 608 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 609 610 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 611 MODULE_LICENSE("GPL"); 612 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 613