542 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Interface to Linux block layer for MTD 'translation layers'.4 *5 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>6 */7 8#include <linux/kernel.h>9#include <linux/slab.h>10#include <linux/module.h>11#include <linux/list.h>12#include <linux/fs.h>13#include <linux/mtd/blktrans.h>14#include <linux/mtd/mtd.h>15#include <linux/blkdev.h>16#include <linux/blk-mq.h>17#include <linux/blkpg.h>18#include <linux/spinlock.h>19#include <linux/hdreg.h>20#include <linux/mutex.h>21#include <linux/uaccess.h>22 23#include "mtdcore.h"24 25static LIST_HEAD(blktrans_majors);26 27static void blktrans_dev_release(struct kref *kref)28{29 struct mtd_blktrans_dev *dev =30 container_of(kref, struct mtd_blktrans_dev, ref);31 32 put_disk(dev->disk);33 blk_mq_free_tag_set(dev->tag_set);34 kfree(dev->tag_set);35 list_del(&dev->list);36 kfree(dev);37}38 39static void blktrans_dev_put(struct mtd_blktrans_dev *dev)40{41 kref_put(&dev->ref, blktrans_dev_release);42}43 44 45static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,46 struct mtd_blktrans_dev *dev,47 struct request *req)48{49 struct req_iterator iter;50 struct bio_vec bvec;51 unsigned long block, nsect;52 char *buf;53 54 block = blk_rq_pos(req) << 9 >> tr->blkshift;55 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;56 57 switch (req_op(req)) {58 case REQ_OP_FLUSH:59 if (tr->flush(dev))60 return BLK_STS_IOERR;61 return BLK_STS_OK;62 case REQ_OP_DISCARD:63 if (tr->discard(dev, block, nsect))64 return BLK_STS_IOERR;65 return BLK_STS_OK;66 case REQ_OP_READ:67 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);68 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {69 if (tr->readsect(dev, block, buf)) {70 kunmap(bio_page(req->bio));71 return BLK_STS_IOERR;72 }73 }74 kunmap(bio_page(req->bio));75 76 rq_for_each_segment(bvec, req, iter)77 flush_dcache_page(bvec.bv_page);78 return BLK_STS_OK;79 case REQ_OP_WRITE:80 if (!tr->writesect)81 return BLK_STS_IOERR;82 83 rq_for_each_segment(bvec, req, iter)84 flush_dcache_page(bvec.bv_page);85 86 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);87 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {88 if (tr->writesect(dev, block, buf)) {89 kunmap(bio_page(req->bio));90 return BLK_STS_IOERR;91 }92 }93 kunmap(bio_page(req->bio));94 return BLK_STS_OK;95 default:96 return BLK_STS_IOERR;97 }98}99 100int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)101{102 return dev->bg_stop;103}104EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);105 106static struct request *mtd_next_request(struct mtd_blktrans_dev *dev)107{108 struct request *rq;109 110 rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);111 if (rq) {112 list_del_init(&rq->queuelist);113 blk_mq_start_request(rq);114 return rq;115 }116 117 return NULL;118}119 120static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)121 __releases(&dev->queue_lock)122 __acquires(&dev->queue_lock)123{124 struct mtd_blktrans_ops *tr = dev->tr;125 struct request *req = NULL;126 int background_done = 0;127 128 while (1) {129 blk_status_t res;130 131 dev->bg_stop = false;132 if (!req && !(req = mtd_next_request(dev))) {133 if (tr->background && !background_done) {134 spin_unlock_irq(&dev->queue_lock);135 mutex_lock(&dev->lock);136 tr->background(dev);137 mutex_unlock(&dev->lock);138 spin_lock_irq(&dev->queue_lock);139 /*140 * Do background processing just once per idle141 * period.142 */143 background_done = !dev->bg_stop;144 continue;145 }146 break;147 }148 149 spin_unlock_irq(&dev->queue_lock);150 151 mutex_lock(&dev->lock);152 res = do_blktrans_request(dev->tr, dev, req);153 mutex_unlock(&dev->lock);154 155 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {156 __blk_mq_end_request(req, res);157 req = NULL;158 }159 160 background_done = 0;161 cond_resched();162 spin_lock_irq(&dev->queue_lock);163 }164}165 166static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,167 const struct blk_mq_queue_data *bd)168{169 struct mtd_blktrans_dev *dev;170 171 dev = hctx->queue->queuedata;172 if (!dev) {173 blk_mq_start_request(bd->rq);174 return BLK_STS_IOERR;175 }176 177 spin_lock_irq(&dev->queue_lock);178 list_add_tail(&bd->rq->queuelist, &dev->rq_list);179 mtd_blktrans_work(dev);180 spin_unlock_irq(&dev->queue_lock);181 182 return BLK_STS_OK;183}184 185static int blktrans_open(struct gendisk *disk, blk_mode_t mode)186{187 struct mtd_blktrans_dev *dev = disk->private_data;188 int ret = 0;189 190 kref_get(&dev->ref);191 192 mutex_lock(&dev->lock);193 194 if (dev->open)195 goto unlock;196 197 __module_get(dev->tr->owner);198 199 if (!dev->mtd)200 goto unlock;201 202 if (dev->tr->open) {203 ret = dev->tr->open(dev);204 if (ret)205 goto error_put;206 }207 208 ret = __get_mtd_device(dev->mtd);209 if (ret)210 goto error_release;211 dev->writable = mode & BLK_OPEN_WRITE;212 213unlock:214 dev->open++;215 mutex_unlock(&dev->lock);216 return ret;217 218error_release:219 if (dev->tr->release)220 dev->tr->release(dev);221error_put:222 module_put(dev->tr->owner);223 mutex_unlock(&dev->lock);224 blktrans_dev_put(dev);225 return ret;226}227 228static void blktrans_release(struct gendisk *disk)229{230 struct mtd_blktrans_dev *dev = disk->private_data;231 232 mutex_lock(&dev->lock);233 234 if (--dev->open)235 goto unlock;236 237 module_put(dev->tr->owner);238 239 if (dev->mtd) {240 if (dev->tr->release)241 dev->tr->release(dev);242 __put_mtd_device(dev->mtd);243 }244unlock:245 mutex_unlock(&dev->lock);246 blktrans_dev_put(dev);247}248 249static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)250{251 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;252 int ret = -ENXIO;253 254 mutex_lock(&dev->lock);255 256 if (!dev->mtd)257 goto unlock;258 259 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;260unlock:261 mutex_unlock(&dev->lock);262 return ret;263}264 265static const struct block_device_operations mtd_block_ops = {266 .owner = THIS_MODULE,267 .open = blktrans_open,268 .release = blktrans_release,269 .getgeo = blktrans_getgeo,270};271 272static const struct blk_mq_ops mtd_mq_ops = {273 .queue_rq = mtd_queue_rq,274};275 276int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)277{278 struct mtd_blktrans_ops *tr = new->tr;279 struct mtd_blktrans_dev *d;280 struct queue_limits lim = { };281 int last_devnum = -1;282 struct gendisk *gd;283 int ret;284 285 lockdep_assert_held(&mtd_table_mutex);286 287 list_for_each_entry(d, &tr->devs, list) {288 if (new->devnum == -1) {289 /* Use first free number */290 if (d->devnum != last_devnum+1) {291 /* Found a free devnum. Plug it in here */292 new->devnum = last_devnum+1;293 list_add_tail(&new->list, &d->list);294 goto added;295 }296 } else if (d->devnum == new->devnum) {297 /* Required number taken */298 return -EBUSY;299 } else if (d->devnum > new->devnum) {300 /* Required number was free */301 list_add_tail(&new->list, &d->list);302 goto added;303 }304 last_devnum = d->devnum;305 }306 307 ret = -EBUSY;308 if (new->devnum == -1)309 new->devnum = last_devnum+1;310 311 /* Check that the device and any partitions will get valid312 * minor numbers and that the disk naming code below can cope313 * with this number. */314 if (new->devnum > (MINORMASK >> tr->part_bits) ||315 (tr->part_bits && new->devnum >= 27 * 26))316 return ret;317 318 list_add_tail(&new->list, &tr->devs);319 added:320 321 mutex_init(&new->lock);322 kref_init(&new->ref);323 if (!tr->writesect)324 new->readonly = 1;325 326 ret = -ENOMEM;327 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);328 if (!new->tag_set)329 goto out_list_del;330 331 ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,332 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);333 if (ret)334 goto out_kfree_tag_set;335 336 lim.logical_block_size = tr->blksize;337 if (tr->discard)338 lim.max_hw_discard_sectors = UINT_MAX;339 if (tr->flush)340 lim.features |= BLK_FEAT_WRITE_CACHE;341 342 /* Create gendisk */343 gd = blk_mq_alloc_disk(new->tag_set, &lim, new);344 if (IS_ERR(gd)) {345 ret = PTR_ERR(gd);346 goto out_free_tag_set;347 }348 349 new->disk = gd;350 new->rq = new->disk->queue;351 gd->private_data = new;352 gd->major = tr->major;353 gd->first_minor = (new->devnum) << tr->part_bits;354 gd->minors = 1 << tr->part_bits;355 gd->fops = &mtd_block_ops;356 357 if (tr->part_bits) {358 if (new->devnum < 26)359 snprintf(gd->disk_name, sizeof(gd->disk_name),360 "%s%c", tr->name, 'a' + new->devnum);361 else362 snprintf(gd->disk_name, sizeof(gd->disk_name),363 "%s%c%c", tr->name,364 'a' - 1 + new->devnum / 26,365 'a' + new->devnum % 26);366 } else {367 snprintf(gd->disk_name, sizeof(gd->disk_name),368 "%s%d", tr->name, new->devnum);369 gd->flags |= GENHD_FL_NO_PART;370 }371 372 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);373 374 /* Create the request queue */375 spin_lock_init(&new->queue_lock);376 INIT_LIST_HEAD(&new->rq_list);377 gd->queue = new->rq;378 379 if (new->readonly)380 set_disk_ro(gd, 1);381 382 ret = device_add_disk(&new->mtd->dev, gd, NULL);383 if (ret)384 goto out_cleanup_disk;385 386 if (new->disk_attributes) {387 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,388 new->disk_attributes);389 WARN_ON(ret);390 }391 return 0;392 393out_cleanup_disk:394 put_disk(new->disk);395out_free_tag_set:396 blk_mq_free_tag_set(new->tag_set);397out_kfree_tag_set:398 kfree(new->tag_set);399out_list_del:400 list_del(&new->list);401 return ret;402}403 404int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)405{406 unsigned long flags;407 408 lockdep_assert_held(&mtd_table_mutex);409 410 if (old->disk_attributes)411 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,412 old->disk_attributes);413 414 /* Stop new requests to arrive */415 del_gendisk(old->disk);416 417 /* Kill current requests */418 spin_lock_irqsave(&old->queue_lock, flags);419 old->rq->queuedata = NULL;420 spin_unlock_irqrestore(&old->queue_lock, flags);421 422 /* freeze+quiesce queue to ensure all requests are flushed */423 blk_mq_freeze_queue(old->rq);424 blk_mq_quiesce_queue(old->rq);425 blk_mq_unquiesce_queue(old->rq);426 blk_mq_unfreeze_queue(old->rq);427 428 /* If the device is currently open, tell trans driver to close it,429 then put mtd device, and don't touch it again */430 mutex_lock(&old->lock);431 if (old->open) {432 if (old->tr->release)433 old->tr->release(old);434 __put_mtd_device(old->mtd);435 }436 437 old->mtd = NULL;438 439 mutex_unlock(&old->lock);440 blktrans_dev_put(old);441 return 0;442}443 444static void blktrans_notify_remove(struct mtd_info *mtd)445{446 struct mtd_blktrans_ops *tr;447 struct mtd_blktrans_dev *dev, *next;448 449 list_for_each_entry(tr, &blktrans_majors, list)450 list_for_each_entry_safe(dev, next, &tr->devs, list)451 if (dev->mtd == mtd)452 tr->remove_dev(dev);453}454 455static void blktrans_notify_add(struct mtd_info *mtd)456{457 struct mtd_blktrans_ops *tr;458 459 if (mtd->type == MTD_ABSENT || mtd->type == MTD_UBIVOLUME)460 return;461 462 list_for_each_entry(tr, &blktrans_majors, list)463 tr->add_mtd(tr, mtd);464}465 466static struct mtd_notifier blktrans_notifier = {467 .add = blktrans_notify_add,468 .remove = blktrans_notify_remove,469};470 471int register_mtd_blktrans(struct mtd_blktrans_ops *tr)472{473 struct mtd_info *mtd;474 int ret;475 476 /* Register the notifier if/when the first device type is477 registered, to prevent the link/init ordering from fucking478 us over. */479 if (!blktrans_notifier.list.next)480 register_mtd_user(&blktrans_notifier);481 482 ret = register_blkdev(tr->major, tr->name);483 if (ret < 0) {484 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",485 tr->name, tr->major, ret);486 return ret;487 }488 489 if (ret)490 tr->major = ret;491 492 tr->blkshift = ffs(tr->blksize) - 1;493 494 INIT_LIST_HEAD(&tr->devs);495 496 mutex_lock(&mtd_table_mutex);497 list_add(&tr->list, &blktrans_majors);498 mtd_for_each_device(mtd)499 if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME)500 tr->add_mtd(tr, mtd);501 mutex_unlock(&mtd_table_mutex);502 return 0;503}504 505int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)506{507 struct mtd_blktrans_dev *dev, *next;508 509 mutex_lock(&mtd_table_mutex);510 511 /* Remove it from the list of active majors */512 list_del(&tr->list);513 514 list_for_each_entry_safe(dev, next, &tr->devs, list)515 tr->remove_dev(dev);516 517 mutex_unlock(&mtd_table_mutex);518 unregister_blkdev(tr->major, tr->name);519 520 BUG_ON(!list_empty(&tr->devs));521 return 0;522}523 524static void __exit mtd_blktrans_exit(void)525{526 /* No race here -- if someone's currently in register_mtd_blktrans527 we're screwed anyway. */528 if (blktrans_notifier.list.next)529 unregister_mtd_user(&blktrans_notifier);530}531 532module_exit(mtd_blktrans_exit);533 534EXPORT_SYMBOL_GPL(register_mtd_blktrans);535EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);536EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);537EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);538 539MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");540MODULE_LICENSE("GPL");541MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");542