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 dev->file_mode = mode; 237 238 unlock: 239 dev->open++; 240 mutex_unlock(&dev->lock); 241 blktrans_dev_put(dev); 242 return ret; 243 244 error_release: 245 if (dev->tr->release) 246 dev->tr->release(dev); 247 error_put: 248 module_put(dev->tr->owner); 249 kref_put(&dev->ref, blktrans_dev_release); 250 mutex_unlock(&dev->lock); 251 blktrans_dev_put(dev); 252 return ret; 253 } 254 255 static int blktrans_release(struct gendisk *disk, fmode_t mode) 256 { 257 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 258 int ret = 0; 259 260 if (!dev) 261 return ret; 262 263 mutex_lock(&dev->lock); 264 265 if (--dev->open) 266 goto unlock; 267 268 kref_put(&dev->ref, blktrans_dev_release); 269 module_put(dev->tr->owner); 270 271 if (dev->mtd) { 272 ret = dev->tr->release ? dev->tr->release(dev) : 0; 273 __put_mtd_device(dev->mtd); 274 } 275 unlock: 276 mutex_unlock(&dev->lock); 277 blktrans_dev_put(dev); 278 return ret; 279 } 280 281 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 282 { 283 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 284 int ret = -ENXIO; 285 286 if (!dev) 287 return ret; 288 289 mutex_lock(&dev->lock); 290 291 if (!dev->mtd) 292 goto unlock; 293 294 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; 295 unlock: 296 mutex_unlock(&dev->lock); 297 blktrans_dev_put(dev); 298 return ret; 299 } 300 301 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 302 unsigned int cmd, unsigned long arg) 303 { 304 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 305 int ret = -ENXIO; 306 307 if (!dev) 308 return ret; 309 310 mutex_lock(&dev->lock); 311 312 if (!dev->mtd) 313 goto unlock; 314 315 switch (cmd) { 316 case BLKFLSBUF: 317 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 318 break; 319 default: 320 ret = -ENOTTY; 321 } 322 unlock: 323 mutex_unlock(&dev->lock); 324 blktrans_dev_put(dev); 325 return ret; 326 } 327 328 static const struct block_device_operations mtd_blktrans_ops = { 329 .owner = THIS_MODULE, 330 .open = blktrans_open, 331 .release = blktrans_release, 332 .ioctl = blktrans_ioctl, 333 .getgeo = blktrans_getgeo, 334 }; 335 336 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 337 { 338 struct mtd_blktrans_ops *tr = new->tr; 339 struct mtd_blktrans_dev *d; 340 int last_devnum = -1; 341 struct gendisk *gd; 342 int ret; 343 344 if (mutex_trylock(&mtd_table_mutex)) { 345 mutex_unlock(&mtd_table_mutex); 346 BUG(); 347 } 348 349 mutex_lock(&blktrans_ref_mutex); 350 list_for_each_entry(d, &tr->devs, list) { 351 if (new->devnum == -1) { 352 /* Use first free number */ 353 if (d->devnum != last_devnum+1) { 354 /* Found a free devnum. Plug it in here */ 355 new->devnum = last_devnum+1; 356 list_add_tail(&new->list, &d->list); 357 goto added; 358 } 359 } else if (d->devnum == new->devnum) { 360 /* Required number taken */ 361 mutex_unlock(&blktrans_ref_mutex); 362 return -EBUSY; 363 } else if (d->devnum > new->devnum) { 364 /* Required number was free */ 365 list_add_tail(&new->list, &d->list); 366 goto added; 367 } 368 last_devnum = d->devnum; 369 } 370 371 ret = -EBUSY; 372 if (new->devnum == -1) 373 new->devnum = last_devnum+1; 374 375 /* Check that the device and any partitions will get valid 376 * minor numbers and that the disk naming code below can cope 377 * with this number. */ 378 if (new->devnum > (MINORMASK >> tr->part_bits) || 379 (tr->part_bits && new->devnum >= 27 * 26)) { 380 mutex_unlock(&blktrans_ref_mutex); 381 goto error1; 382 } 383 384 list_add_tail(&new->list, &tr->devs); 385 added: 386 mutex_unlock(&blktrans_ref_mutex); 387 388 mutex_init(&new->lock); 389 kref_init(&new->ref); 390 if (!tr->writesect) 391 new->readonly = 1; 392 393 /* Create gendisk */ 394 ret = -ENOMEM; 395 gd = alloc_disk(1 << tr->part_bits); 396 397 if (!gd) 398 goto error2; 399 400 new->disk = gd; 401 gd->private_data = new; 402 gd->major = tr->major; 403 gd->first_minor = (new->devnum) << tr->part_bits; 404 gd->fops = &mtd_blktrans_ops; 405 406 if (tr->part_bits) 407 if (new->devnum < 26) 408 snprintf(gd->disk_name, sizeof(gd->disk_name), 409 "%s%c", tr->name, 'a' + new->devnum); 410 else 411 snprintf(gd->disk_name, sizeof(gd->disk_name), 412 "%s%c%c", tr->name, 413 'a' - 1 + new->devnum / 26, 414 'a' + new->devnum % 26); 415 else 416 snprintf(gd->disk_name, sizeof(gd->disk_name), 417 "%s%d", tr->name, new->devnum); 418 419 set_capacity(gd, (new->size * tr->blksize) >> 9); 420 421 /* Create the request queue */ 422 spin_lock_init(&new->queue_lock); 423 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 424 425 if (!new->rq) 426 goto error3; 427 428 new->rq->queuedata = new; 429 blk_queue_logical_block_size(new->rq, tr->blksize); 430 431 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); 432 433 if (tr->discard) { 434 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 435 new->rq->limits.max_discard_sectors = UINT_MAX; 436 } 437 438 gd->queue = new->rq; 439 440 /* Create processing thread */ 441 /* TODO: workqueue ? */ 442 new->thread = kthread_run(mtd_blktrans_thread, new, 443 "%s%d", tr->name, new->mtd->index); 444 if (IS_ERR(new->thread)) { 445 ret = PTR_ERR(new->thread); 446 goto error4; 447 } 448 gd->driverfs_dev = &new->mtd->dev; 449 450 if (new->readonly) 451 set_disk_ro(gd, 1); 452 453 add_disk(gd); 454 455 if (new->disk_attributes) { 456 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 457 new->disk_attributes); 458 WARN_ON(ret); 459 } 460 return 0; 461 error4: 462 blk_cleanup_queue(new->rq); 463 error3: 464 put_disk(new->disk); 465 error2: 466 list_del(&new->list); 467 error1: 468 return ret; 469 } 470 471 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 472 { 473 unsigned long flags; 474 475 if (mutex_trylock(&mtd_table_mutex)) { 476 mutex_unlock(&mtd_table_mutex); 477 BUG(); 478 } 479 480 if (old->disk_attributes) 481 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 482 old->disk_attributes); 483 484 /* Stop new requests to arrive */ 485 del_gendisk(old->disk); 486 487 488 /* Stop the thread */ 489 kthread_stop(old->thread); 490 491 /* Kill current requests */ 492 spin_lock_irqsave(&old->queue_lock, flags); 493 old->rq->queuedata = NULL; 494 blk_start_queue(old->rq); 495 spin_unlock_irqrestore(&old->queue_lock, flags); 496 497 /* If the device is currently open, tell trans driver to close it, 498 then put mtd device, and don't touch it again */ 499 mutex_lock(&old->lock); 500 if (old->open) { 501 if (old->tr->release) 502 old->tr->release(old); 503 __put_mtd_device(old->mtd); 504 } 505 506 old->mtd = NULL; 507 508 mutex_unlock(&old->lock); 509 blktrans_dev_put(old); 510 return 0; 511 } 512 513 static void blktrans_notify_remove(struct mtd_info *mtd) 514 { 515 struct mtd_blktrans_ops *tr; 516 struct mtd_blktrans_dev *dev, *next; 517 518 list_for_each_entry(tr, &blktrans_majors, list) 519 list_for_each_entry_safe(dev, next, &tr->devs, list) 520 if (dev->mtd == mtd) 521 tr->remove_dev(dev); 522 } 523 524 static void blktrans_notify_add(struct mtd_info *mtd) 525 { 526 struct mtd_blktrans_ops *tr; 527 528 if (mtd->type == MTD_ABSENT) 529 return; 530 531 list_for_each_entry(tr, &blktrans_majors, list) 532 tr->add_mtd(tr, mtd); 533 } 534 535 static struct mtd_notifier blktrans_notifier = { 536 .add = blktrans_notify_add, 537 .remove = blktrans_notify_remove, 538 }; 539 540 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 541 { 542 struct mtd_info *mtd; 543 int ret; 544 545 /* Register the notifier if/when the first device type is 546 registered, to prevent the link/init ordering from fucking 547 us over. */ 548 if (!blktrans_notifier.list.next) 549 register_mtd_user(&blktrans_notifier); 550 551 552 mutex_lock(&mtd_table_mutex); 553 554 ret = register_blkdev(tr->major, tr->name); 555 if (ret < 0) { 556 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 557 tr->name, tr->major, ret); 558 mutex_unlock(&mtd_table_mutex); 559 return ret; 560 } 561 562 if (ret) 563 tr->major = ret; 564 565 tr->blkshift = ffs(tr->blksize) - 1; 566 567 INIT_LIST_HEAD(&tr->devs); 568 list_add(&tr->list, &blktrans_majors); 569 570 mtd_for_each_device(mtd) 571 if (mtd->type != MTD_ABSENT) 572 tr->add_mtd(tr, mtd); 573 574 mutex_unlock(&mtd_table_mutex); 575 return 0; 576 } 577 578 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 579 { 580 struct mtd_blktrans_dev *dev, *next; 581 582 mutex_lock(&mtd_table_mutex); 583 584 /* Remove it from the list of active majors */ 585 list_del(&tr->list); 586 587 list_for_each_entry_safe(dev, next, &tr->devs, list) 588 tr->remove_dev(dev); 589 590 unregister_blkdev(tr->major, tr->name); 591 mutex_unlock(&mtd_table_mutex); 592 593 BUG_ON(!list_empty(&tr->devs)); 594 return 0; 595 } 596 597 static void __exit mtd_blktrans_exit(void) 598 { 599 /* No race here -- if someone's currently in register_mtd_blktrans 600 we're screwed anyway. */ 601 if (blktrans_notifier.list.next) 602 unregister_mtd_user(&blktrans_notifier); 603 } 604 605 module_exit(mtd_blktrans_exit); 606 607 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 608 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 609 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 610 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 611 612 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 613 MODULE_LICENSE("GPL"); 614 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 615