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 ret = dev->tr->open ? dev->tr->open(dev) : 0; 226 __get_mtd_device(dev->mtd); 227 } 228 229 unlock: 230 mutex_unlock(&dev->lock); 231 blktrans_dev_put(dev); 232 return ret; 233 } 234 235 static int blktrans_release(struct gendisk *disk, fmode_t mode) 236 { 237 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 238 int ret = 0; 239 240 if (!dev) 241 return ret; 242 243 mutex_lock(&dev->lock); 244 245 if (--dev->open) 246 goto unlock; 247 248 kref_put(&dev->ref, blktrans_dev_release); 249 module_put(dev->tr->owner); 250 251 if (dev->mtd) { 252 ret = dev->tr->release ? dev->tr->release(dev) : 0; 253 __put_mtd_device(dev->mtd); 254 } 255 unlock: 256 mutex_unlock(&dev->lock); 257 blktrans_dev_put(dev); 258 return ret; 259 } 260 261 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 262 { 263 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 264 int ret = -ENXIO; 265 266 if (!dev) 267 return ret; 268 269 mutex_lock(&dev->lock); 270 271 if (!dev->mtd) 272 goto unlock; 273 274 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; 275 unlock: 276 mutex_unlock(&dev->lock); 277 blktrans_dev_put(dev); 278 return ret; 279 } 280 281 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 282 unsigned int cmd, unsigned long arg) 283 { 284 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 285 int ret = -ENXIO; 286 287 if (!dev) 288 return ret; 289 290 mutex_lock(&dev->lock); 291 292 if (!dev->mtd) 293 goto unlock; 294 295 switch (cmd) { 296 case BLKFLSBUF: 297 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 298 break; 299 default: 300 ret = -ENOTTY; 301 } 302 unlock: 303 mutex_unlock(&dev->lock); 304 blktrans_dev_put(dev); 305 return ret; 306 } 307 308 static const struct block_device_operations mtd_blktrans_ops = { 309 .owner = THIS_MODULE, 310 .open = blktrans_open, 311 .release = blktrans_release, 312 .ioctl = blktrans_ioctl, 313 .getgeo = blktrans_getgeo, 314 }; 315 316 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 317 { 318 struct mtd_blktrans_ops *tr = new->tr; 319 struct mtd_blktrans_dev *d; 320 int last_devnum = -1; 321 struct gendisk *gd; 322 int ret; 323 324 if (mutex_trylock(&mtd_table_mutex)) { 325 mutex_unlock(&mtd_table_mutex); 326 BUG(); 327 } 328 329 mutex_lock(&blktrans_ref_mutex); 330 list_for_each_entry(d, &tr->devs, list) { 331 if (new->devnum == -1) { 332 /* Use first free number */ 333 if (d->devnum != last_devnum+1) { 334 /* Found a free devnum. Plug it in here */ 335 new->devnum = last_devnum+1; 336 list_add_tail(&new->list, &d->list); 337 goto added; 338 } 339 } else if (d->devnum == new->devnum) { 340 /* Required number taken */ 341 mutex_unlock(&blktrans_ref_mutex); 342 return -EBUSY; 343 } else if (d->devnum > new->devnum) { 344 /* Required number was free */ 345 list_add_tail(&new->list, &d->list); 346 goto added; 347 } 348 last_devnum = d->devnum; 349 } 350 351 ret = -EBUSY; 352 if (new->devnum == -1) 353 new->devnum = last_devnum+1; 354 355 /* Check that the device and any partitions will get valid 356 * minor numbers and that the disk naming code below can cope 357 * with this number. */ 358 if (new->devnum > (MINORMASK >> tr->part_bits) || 359 (tr->part_bits && new->devnum >= 27 * 26)) { 360 mutex_unlock(&blktrans_ref_mutex); 361 goto error1; 362 } 363 364 list_add_tail(&new->list, &tr->devs); 365 added: 366 mutex_unlock(&blktrans_ref_mutex); 367 368 mutex_init(&new->lock); 369 kref_init(&new->ref); 370 if (!tr->writesect) 371 new->readonly = 1; 372 373 /* Create gendisk */ 374 ret = -ENOMEM; 375 gd = alloc_disk(1 << tr->part_bits); 376 377 if (!gd) 378 goto error2; 379 380 new->disk = gd; 381 gd->private_data = new; 382 gd->major = tr->major; 383 gd->first_minor = (new->devnum) << tr->part_bits; 384 gd->fops = &mtd_blktrans_ops; 385 386 if (tr->part_bits) 387 if (new->devnum < 26) 388 snprintf(gd->disk_name, sizeof(gd->disk_name), 389 "%s%c", tr->name, 'a' + new->devnum); 390 else 391 snprintf(gd->disk_name, sizeof(gd->disk_name), 392 "%s%c%c", tr->name, 393 'a' - 1 + new->devnum / 26, 394 'a' + new->devnum % 26); 395 else 396 snprintf(gd->disk_name, sizeof(gd->disk_name), 397 "%s%d", tr->name, new->devnum); 398 399 set_capacity(gd, (new->size * tr->blksize) >> 9); 400 401 /* Create the request queue */ 402 spin_lock_init(&new->queue_lock); 403 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); 404 405 if (!new->rq) 406 goto error3; 407 408 new->rq->queuedata = new; 409 blk_queue_logical_block_size(new->rq, tr->blksize); 410 411 if (tr->discard) { 412 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); 413 new->rq->limits.max_discard_sectors = UINT_MAX; 414 } 415 416 gd->queue = new->rq; 417 418 /* Create processing thread */ 419 /* TODO: workqueue ? */ 420 new->thread = kthread_run(mtd_blktrans_thread, new, 421 "%s%d", tr->name, new->mtd->index); 422 if (IS_ERR(new->thread)) { 423 ret = PTR_ERR(new->thread); 424 goto error4; 425 } 426 gd->driverfs_dev = &new->mtd->dev; 427 428 if (new->readonly) 429 set_disk_ro(gd, 1); 430 431 add_disk(gd); 432 433 if (new->disk_attributes) { 434 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 435 new->disk_attributes); 436 WARN_ON(ret); 437 } 438 return 0; 439 error4: 440 blk_cleanup_queue(new->rq); 441 error3: 442 put_disk(new->disk); 443 error2: 444 list_del(&new->list); 445 error1: 446 return ret; 447 } 448 449 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 450 { 451 unsigned long flags; 452 453 if (mutex_trylock(&mtd_table_mutex)) { 454 mutex_unlock(&mtd_table_mutex); 455 BUG(); 456 } 457 458 if (old->disk_attributes) 459 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 460 old->disk_attributes); 461 462 /* Stop new requests to arrive */ 463 del_gendisk(old->disk); 464 465 466 /* Stop the thread */ 467 kthread_stop(old->thread); 468 469 /* Kill current requests */ 470 spin_lock_irqsave(&old->queue_lock, flags); 471 old->rq->queuedata = NULL; 472 blk_start_queue(old->rq); 473 spin_unlock_irqrestore(&old->queue_lock, flags); 474 475 /* If the device is currently open, tell trans driver to close it, 476 then put mtd device, and don't touch it again */ 477 mutex_lock(&old->lock); 478 if (old->open) { 479 if (old->tr->release) 480 old->tr->release(old); 481 __put_mtd_device(old->mtd); 482 } 483 484 old->mtd = NULL; 485 486 mutex_unlock(&old->lock); 487 blktrans_dev_put(old); 488 return 0; 489 } 490 491 static void blktrans_notify_remove(struct mtd_info *mtd) 492 { 493 struct mtd_blktrans_ops *tr; 494 struct mtd_blktrans_dev *dev, *next; 495 496 list_for_each_entry(tr, &blktrans_majors, list) 497 list_for_each_entry_safe(dev, next, &tr->devs, list) 498 if (dev->mtd == mtd) 499 tr->remove_dev(dev); 500 } 501 502 static void blktrans_notify_add(struct mtd_info *mtd) 503 { 504 struct mtd_blktrans_ops *tr; 505 506 if (mtd->type == MTD_ABSENT) 507 return; 508 509 list_for_each_entry(tr, &blktrans_majors, list) 510 tr->add_mtd(tr, mtd); 511 } 512 513 static struct mtd_notifier blktrans_notifier = { 514 .add = blktrans_notify_add, 515 .remove = blktrans_notify_remove, 516 }; 517 518 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 519 { 520 struct mtd_info *mtd; 521 int ret; 522 523 /* Register the notifier if/when the first device type is 524 registered, to prevent the link/init ordering from fucking 525 us over. */ 526 if (!blktrans_notifier.list.next) 527 register_mtd_user(&blktrans_notifier); 528 529 530 mutex_lock(&mtd_table_mutex); 531 532 ret = register_blkdev(tr->major, tr->name); 533 if (ret < 0) { 534 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 535 tr->name, tr->major, ret); 536 mutex_unlock(&mtd_table_mutex); 537 return ret; 538 } 539 540 if (ret) 541 tr->major = ret; 542 543 tr->blkshift = ffs(tr->blksize) - 1; 544 545 INIT_LIST_HEAD(&tr->devs); 546 list_add(&tr->list, &blktrans_majors); 547 548 mtd_for_each_device(mtd) 549 if (mtd->type != MTD_ABSENT) 550 tr->add_mtd(tr, mtd); 551 552 mutex_unlock(&mtd_table_mutex); 553 return 0; 554 } 555 556 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 557 { 558 struct mtd_blktrans_dev *dev, *next; 559 560 mutex_lock(&mtd_table_mutex); 561 562 /* Remove it from the list of active majors */ 563 list_del(&tr->list); 564 565 list_for_each_entry_safe(dev, next, &tr->devs, list) 566 tr->remove_dev(dev); 567 568 unregister_blkdev(tr->major, tr->name); 569 mutex_unlock(&mtd_table_mutex); 570 571 BUG_ON(!list_empty(&tr->devs)); 572 return 0; 573 } 574 575 static void __exit mtd_blktrans_exit(void) 576 { 577 /* No race here -- if someone's currently in register_mtd_blktrans 578 we're screwed anyway. */ 579 if (blktrans_notifier.list.next) 580 unregister_mtd_user(&blktrans_notifier); 581 } 582 583 module_exit(mtd_blktrans_exit); 584 585 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 586 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 587 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 588 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 589 590 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 591 MODULE_LICENSE("GPL"); 592 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 593