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/blk-mq.h> 31 #include <linux/blkpg.h> 32 #include <linux/spinlock.h> 33 #include <linux/hdreg.h> 34 #include <linux/mutex.h> 35 #include <linux/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 blk_mq_free_tag_set(dev->tag_set); 50 kfree(dev->tag_set); 51 put_disk(dev->disk); 52 list_del(&dev->list); 53 kfree(dev); 54 } 55 56 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk) 57 { 58 struct mtd_blktrans_dev *dev; 59 60 mutex_lock(&blktrans_ref_mutex); 61 dev = disk->private_data; 62 63 if (!dev) 64 goto unlock; 65 kref_get(&dev->ref); 66 unlock: 67 mutex_unlock(&blktrans_ref_mutex); 68 return dev; 69 } 70 71 static void blktrans_dev_put(struct mtd_blktrans_dev *dev) 72 { 73 mutex_lock(&blktrans_ref_mutex); 74 kref_put(&dev->ref, blktrans_dev_release); 75 mutex_unlock(&blktrans_ref_mutex); 76 } 77 78 79 static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr, 80 struct mtd_blktrans_dev *dev, 81 struct request *req) 82 { 83 unsigned long block, nsect; 84 char *buf; 85 86 block = blk_rq_pos(req) << 9 >> tr->blkshift; 87 nsect = blk_rq_cur_bytes(req) >> tr->blkshift; 88 89 if (req_op(req) == REQ_OP_FLUSH) { 90 if (tr->flush(dev)) 91 return BLK_STS_IOERR; 92 return BLK_STS_OK; 93 } 94 95 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > 96 get_capacity(req->rq_disk)) 97 return BLK_STS_IOERR; 98 99 switch (req_op(req)) { 100 case REQ_OP_DISCARD: 101 if (tr->discard(dev, block, nsect)) 102 return BLK_STS_IOERR; 103 return BLK_STS_OK; 104 case REQ_OP_READ: 105 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); 106 for (; nsect > 0; nsect--, block++, buf += tr->blksize) { 107 if (tr->readsect(dev, block, buf)) { 108 kunmap(bio_page(req->bio)); 109 return BLK_STS_IOERR; 110 } 111 } 112 kunmap(bio_page(req->bio)); 113 rq_flush_dcache_pages(req); 114 return BLK_STS_OK; 115 case REQ_OP_WRITE: 116 if (!tr->writesect) 117 return BLK_STS_IOERR; 118 119 rq_flush_dcache_pages(req); 120 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); 121 for (; nsect > 0; nsect--, block++, buf += tr->blksize) { 122 if (tr->writesect(dev, block, buf)) { 123 kunmap(bio_page(req->bio)); 124 return BLK_STS_IOERR; 125 } 126 } 127 kunmap(bio_page(req->bio)); 128 return BLK_STS_OK; 129 default: 130 return BLK_STS_IOERR; 131 } 132 } 133 134 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) 135 { 136 return dev->bg_stop; 137 } 138 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); 139 140 static struct request *mtd_next_request(struct mtd_blktrans_dev *dev) 141 { 142 struct request *rq; 143 144 rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist); 145 if (rq) { 146 list_del_init(&rq->queuelist); 147 blk_mq_start_request(rq); 148 return rq; 149 } 150 151 return NULL; 152 } 153 154 static void mtd_blktrans_work(struct mtd_blktrans_dev *dev) 155 __releases(&dev->queue_lock) 156 __acquires(&dev->queue_lock) 157 { 158 struct mtd_blktrans_ops *tr = dev->tr; 159 struct request *req = NULL; 160 int background_done = 0; 161 162 while (1) { 163 blk_status_t res; 164 165 dev->bg_stop = false; 166 if (!req && !(req = mtd_next_request(dev))) { 167 if (tr->background && !background_done) { 168 spin_unlock_irq(&dev->queue_lock); 169 mutex_lock(&dev->lock); 170 tr->background(dev); 171 mutex_unlock(&dev->lock); 172 spin_lock_irq(&dev->queue_lock); 173 /* 174 * Do background processing just once per idle 175 * period. 176 */ 177 background_done = !dev->bg_stop; 178 continue; 179 } 180 break; 181 } 182 183 spin_unlock_irq(&dev->queue_lock); 184 185 mutex_lock(&dev->lock); 186 res = do_blktrans_request(dev->tr, dev, req); 187 mutex_unlock(&dev->lock); 188 189 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) { 190 __blk_mq_end_request(req, res); 191 req = NULL; 192 } 193 194 background_done = 0; 195 spin_lock_irq(&dev->queue_lock); 196 } 197 } 198 199 static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx, 200 const struct blk_mq_queue_data *bd) 201 { 202 struct mtd_blktrans_dev *dev; 203 204 dev = hctx->queue->queuedata; 205 if (!dev) { 206 blk_mq_start_request(bd->rq); 207 return BLK_STS_IOERR; 208 } 209 210 spin_lock_irq(&dev->queue_lock); 211 list_add_tail(&bd->rq->queuelist, &dev->rq_list); 212 mtd_blktrans_work(dev); 213 spin_unlock_irq(&dev->queue_lock); 214 215 return BLK_STS_OK; 216 } 217 218 static int blktrans_open(struct block_device *bdev, fmode_t mode) 219 { 220 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 221 int ret = 0; 222 223 if (!dev) 224 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ 225 226 mutex_lock(&mtd_table_mutex); 227 mutex_lock(&dev->lock); 228 229 if (dev->open) 230 goto unlock; 231 232 kref_get(&dev->ref); 233 __module_get(dev->tr->owner); 234 235 if (!dev->mtd) 236 goto unlock; 237 238 if (dev->tr->open) { 239 ret = dev->tr->open(dev); 240 if (ret) 241 goto error_put; 242 } 243 244 ret = __get_mtd_device(dev->mtd); 245 if (ret) 246 goto error_release; 247 dev->file_mode = mode; 248 249 unlock: 250 dev->open++; 251 mutex_unlock(&dev->lock); 252 mutex_unlock(&mtd_table_mutex); 253 blktrans_dev_put(dev); 254 return ret; 255 256 error_release: 257 if (dev->tr->release) 258 dev->tr->release(dev); 259 error_put: 260 module_put(dev->tr->owner); 261 kref_put(&dev->ref, blktrans_dev_release); 262 mutex_unlock(&dev->lock); 263 mutex_unlock(&mtd_table_mutex); 264 blktrans_dev_put(dev); 265 return ret; 266 } 267 268 static void blktrans_release(struct gendisk *disk, fmode_t mode) 269 { 270 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); 271 272 if (!dev) 273 return; 274 275 mutex_lock(&mtd_table_mutex); 276 mutex_lock(&dev->lock); 277 278 if (--dev->open) 279 goto unlock; 280 281 kref_put(&dev->ref, blktrans_dev_release); 282 module_put(dev->tr->owner); 283 284 if (dev->mtd) { 285 if (dev->tr->release) 286 dev->tr->release(dev); 287 __put_mtd_device(dev->mtd); 288 } 289 unlock: 290 mutex_unlock(&dev->lock); 291 mutex_unlock(&mtd_table_mutex); 292 blktrans_dev_put(dev); 293 } 294 295 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) 296 { 297 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 298 int ret = -ENXIO; 299 300 if (!dev) 301 return ret; 302 303 mutex_lock(&dev->lock); 304 305 if (!dev->mtd) 306 goto unlock; 307 308 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY; 309 unlock: 310 mutex_unlock(&dev->lock); 311 blktrans_dev_put(dev); 312 return ret; 313 } 314 315 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, 316 unsigned int cmd, unsigned long arg) 317 { 318 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); 319 int ret = -ENXIO; 320 321 if (!dev) 322 return ret; 323 324 mutex_lock(&dev->lock); 325 326 if (!dev->mtd) 327 goto unlock; 328 329 switch (cmd) { 330 case BLKFLSBUF: 331 ret = dev->tr->flush ? dev->tr->flush(dev) : 0; 332 break; 333 default: 334 ret = -ENOTTY; 335 } 336 unlock: 337 mutex_unlock(&dev->lock); 338 blktrans_dev_put(dev); 339 return ret; 340 } 341 342 static const struct block_device_operations mtd_block_ops = { 343 .owner = THIS_MODULE, 344 .open = blktrans_open, 345 .release = blktrans_release, 346 .ioctl = blktrans_ioctl, 347 .getgeo = blktrans_getgeo, 348 }; 349 350 static const struct blk_mq_ops mtd_mq_ops = { 351 .queue_rq = mtd_queue_rq, 352 }; 353 354 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) 355 { 356 struct mtd_blktrans_ops *tr = new->tr; 357 struct mtd_blktrans_dev *d; 358 int last_devnum = -1; 359 struct gendisk *gd; 360 int ret; 361 362 if (mutex_trylock(&mtd_table_mutex)) { 363 mutex_unlock(&mtd_table_mutex); 364 BUG(); 365 } 366 367 mutex_lock(&blktrans_ref_mutex); 368 list_for_each_entry(d, &tr->devs, list) { 369 if (new->devnum == -1) { 370 /* Use first free number */ 371 if (d->devnum != last_devnum+1) { 372 /* Found a free devnum. Plug it in here */ 373 new->devnum = last_devnum+1; 374 list_add_tail(&new->list, &d->list); 375 goto added; 376 } 377 } else if (d->devnum == new->devnum) { 378 /* Required number taken */ 379 mutex_unlock(&blktrans_ref_mutex); 380 return -EBUSY; 381 } else if (d->devnum > new->devnum) { 382 /* Required number was free */ 383 list_add_tail(&new->list, &d->list); 384 goto added; 385 } 386 last_devnum = d->devnum; 387 } 388 389 ret = -EBUSY; 390 if (new->devnum == -1) 391 new->devnum = last_devnum+1; 392 393 /* Check that the device and any partitions will get valid 394 * minor numbers and that the disk naming code below can cope 395 * with this number. */ 396 if (new->devnum > (MINORMASK >> tr->part_bits) || 397 (tr->part_bits && new->devnum >= 27 * 26)) { 398 mutex_unlock(&blktrans_ref_mutex); 399 goto error1; 400 } 401 402 list_add_tail(&new->list, &tr->devs); 403 added: 404 mutex_unlock(&blktrans_ref_mutex); 405 406 mutex_init(&new->lock); 407 kref_init(&new->ref); 408 if (!tr->writesect) 409 new->readonly = 1; 410 411 /* Create gendisk */ 412 ret = -ENOMEM; 413 gd = alloc_disk(1 << tr->part_bits); 414 415 if (!gd) 416 goto error2; 417 418 new->disk = gd; 419 gd->private_data = new; 420 gd->major = tr->major; 421 gd->first_minor = (new->devnum) << tr->part_bits; 422 gd->fops = &mtd_block_ops; 423 424 if (tr->part_bits) 425 if (new->devnum < 26) 426 snprintf(gd->disk_name, sizeof(gd->disk_name), 427 "%s%c", tr->name, 'a' + new->devnum); 428 else 429 snprintf(gd->disk_name, sizeof(gd->disk_name), 430 "%s%c%c", tr->name, 431 'a' - 1 + new->devnum / 26, 432 'a' + new->devnum % 26); 433 else 434 snprintf(gd->disk_name, sizeof(gd->disk_name), 435 "%s%d", tr->name, new->devnum); 436 437 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9); 438 439 /* Create the request queue */ 440 spin_lock_init(&new->queue_lock); 441 INIT_LIST_HEAD(&new->rq_list); 442 443 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL); 444 if (!new->tag_set) 445 goto error3; 446 447 new->rq = blk_mq_init_sq_queue(new->tag_set, &mtd_mq_ops, 2, 448 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING); 449 if (IS_ERR(new->rq)) { 450 ret = PTR_ERR(new->rq); 451 new->rq = NULL; 452 goto error4; 453 } 454 455 if (tr->flush) 456 blk_queue_write_cache(new->rq, true, false); 457 458 new->rq->queuedata = new; 459 blk_queue_logical_block_size(new->rq, tr->blksize); 460 461 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq); 462 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq); 463 464 if (tr->discard) { 465 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq); 466 blk_queue_max_discard_sectors(new->rq, UINT_MAX); 467 } 468 469 gd->queue = new->rq; 470 471 if (new->readonly) 472 set_disk_ro(gd, 1); 473 474 device_add_disk(&new->mtd->dev, gd, NULL); 475 476 if (new->disk_attributes) { 477 ret = sysfs_create_group(&disk_to_dev(gd)->kobj, 478 new->disk_attributes); 479 WARN_ON(ret); 480 } 481 return 0; 482 error4: 483 kfree(new->tag_set); 484 error3: 485 put_disk(new->disk); 486 error2: 487 list_del(&new->list); 488 error1: 489 return ret; 490 } 491 492 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) 493 { 494 unsigned long flags; 495 496 if (mutex_trylock(&mtd_table_mutex)) { 497 mutex_unlock(&mtd_table_mutex); 498 BUG(); 499 } 500 501 if (old->disk_attributes) 502 sysfs_remove_group(&disk_to_dev(old->disk)->kobj, 503 old->disk_attributes); 504 505 /* Stop new requests to arrive */ 506 del_gendisk(old->disk); 507 508 /* Kill current requests */ 509 spin_lock_irqsave(&old->queue_lock, flags); 510 old->rq->queuedata = NULL; 511 spin_unlock_irqrestore(&old->queue_lock, flags); 512 513 /* freeze+quiesce queue to ensure all requests are flushed */ 514 blk_mq_freeze_queue(old->rq); 515 blk_mq_quiesce_queue(old->rq); 516 blk_mq_unquiesce_queue(old->rq); 517 blk_mq_unfreeze_queue(old->rq); 518 519 /* If the device is currently open, tell trans driver to close it, 520 then put mtd device, and don't touch it again */ 521 mutex_lock(&old->lock); 522 if (old->open) { 523 if (old->tr->release) 524 old->tr->release(old); 525 __put_mtd_device(old->mtd); 526 } 527 528 old->mtd = NULL; 529 530 mutex_unlock(&old->lock); 531 blktrans_dev_put(old); 532 return 0; 533 } 534 535 static void blktrans_notify_remove(struct mtd_info *mtd) 536 { 537 struct mtd_blktrans_ops *tr; 538 struct mtd_blktrans_dev *dev, *next; 539 540 list_for_each_entry(tr, &blktrans_majors, list) 541 list_for_each_entry_safe(dev, next, &tr->devs, list) 542 if (dev->mtd == mtd) 543 tr->remove_dev(dev); 544 } 545 546 static void blktrans_notify_add(struct mtd_info *mtd) 547 { 548 struct mtd_blktrans_ops *tr; 549 550 if (mtd->type == MTD_ABSENT) 551 return; 552 553 list_for_each_entry(tr, &blktrans_majors, list) 554 tr->add_mtd(tr, mtd); 555 } 556 557 static struct mtd_notifier blktrans_notifier = { 558 .add = blktrans_notify_add, 559 .remove = blktrans_notify_remove, 560 }; 561 562 int register_mtd_blktrans(struct mtd_blktrans_ops *tr) 563 { 564 struct mtd_info *mtd; 565 int ret; 566 567 /* Register the notifier if/when the first device type is 568 registered, to prevent the link/init ordering from fucking 569 us over. */ 570 if (!blktrans_notifier.list.next) 571 register_mtd_user(&blktrans_notifier); 572 573 574 mutex_lock(&mtd_table_mutex); 575 576 ret = register_blkdev(tr->major, tr->name); 577 if (ret < 0) { 578 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", 579 tr->name, tr->major, ret); 580 mutex_unlock(&mtd_table_mutex); 581 return ret; 582 } 583 584 if (ret) 585 tr->major = ret; 586 587 tr->blkshift = ffs(tr->blksize) - 1; 588 589 INIT_LIST_HEAD(&tr->devs); 590 list_add(&tr->list, &blktrans_majors); 591 592 mtd_for_each_device(mtd) 593 if (mtd->type != MTD_ABSENT) 594 tr->add_mtd(tr, mtd); 595 596 mutex_unlock(&mtd_table_mutex); 597 return 0; 598 } 599 600 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) 601 { 602 struct mtd_blktrans_dev *dev, *next; 603 604 mutex_lock(&mtd_table_mutex); 605 606 /* Remove it from the list of active majors */ 607 list_del(&tr->list); 608 609 list_for_each_entry_safe(dev, next, &tr->devs, list) 610 tr->remove_dev(dev); 611 612 unregister_blkdev(tr->major, tr->name); 613 mutex_unlock(&mtd_table_mutex); 614 615 BUG_ON(!list_empty(&tr->devs)); 616 return 0; 617 } 618 619 static void __exit mtd_blktrans_exit(void) 620 { 621 /* No race here -- if someone's currently in register_mtd_blktrans 622 we're screwed anyway. */ 623 if (blktrans_notifier.list.next) 624 unregister_mtd_user(&blktrans_notifier); 625 } 626 627 module_exit(mtd_blktrans_exit); 628 629 EXPORT_SYMBOL_GPL(register_mtd_blktrans); 630 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); 631 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); 632 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); 633 634 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 635 MODULE_LICENSE("GPL"); 636 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 637