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