2 * Interface to Linux block layer for MTD 'translation layers'.
4 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
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.
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.
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
22 #include <linux/kernel.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/list.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/mutex.h>
34 #include <asm/uaccess.h>
38 static LIST_HEAD(blktrans_majors);
39 static DEFINE_MUTEX(blktrans_ref_mutex);
41 static void blktrans_dev_release(struct kref *kref)
43 struct mtd_blktrans_dev *dev =
44 container_of(kref, struct mtd_blktrans_dev, ref);
46 dev->disk->private_data = NULL;
47 blk_cleanup_queue(dev->rq);
53 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
55 struct mtd_blktrans_dev *dev;
57 mutex_lock(&blktrans_ref_mutex);
58 dev = disk->private_data;
64 mutex_unlock(&blktrans_ref_mutex);
68 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
70 mutex_lock(&blktrans_ref_mutex);
71 kref_put(&dev->ref, blktrans_dev_release);
72 mutex_unlock(&blktrans_ref_mutex);
76 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
77 struct mtd_blktrans_dev *dev,
80 unsigned long block, nsect;
83 block = blk_rq_pos(req) << 9 >> tr->blkshift;
84 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
88 if (req->cmd_type != REQ_TYPE_FS)
91 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
92 get_capacity(req->rq_disk))
95 if (req->cmd_flags & REQ_DISCARD)
96 return tr->discard(dev, block, nsect);
98 switch(rq_data_dir(req)) {
100 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
101 if (tr->readsect(dev, block, buf))
103 rq_flush_dcache_pages(req);
109 rq_flush_dcache_pages(req);
110 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
111 if (tr->writesect(dev, block, buf))
115 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
120 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
124 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
126 static void mtd_blktrans_work(struct work_struct *work)
128 struct mtd_blktrans_dev *dev =
129 container_of(work, struct mtd_blktrans_dev, work);
130 struct mtd_blktrans_ops *tr = dev->tr;
131 struct request_queue *rq = dev->rq;
132 struct request *req = NULL;
133 int background_done = 0;
135 spin_lock_irq(rq->queue_lock);
140 dev->bg_stop = false;
141 if (!req && !(req = blk_fetch_request(rq))) {
142 if (tr->background && !background_done) {
143 spin_unlock_irq(rq->queue_lock);
144 mutex_lock(&dev->lock);
146 mutex_unlock(&dev->lock);
147 spin_lock_irq(rq->queue_lock);
149 * Do background processing just once per idle
152 background_done = !dev->bg_stop;
158 spin_unlock_irq(rq->queue_lock);
160 mutex_lock(&dev->lock);
161 res = do_blktrans_request(dev->tr, dev, req);
162 mutex_unlock(&dev->lock);
164 spin_lock_irq(rq->queue_lock);
166 if (!__blk_end_request_cur(req, res))
173 __blk_end_request_all(req, -EIO);
175 spin_unlock_irq(rq->queue_lock);
178 static void mtd_blktrans_request(struct request_queue *rq)
180 struct mtd_blktrans_dev *dev;
181 struct request *req = NULL;
186 while ((req = blk_fetch_request(rq)) != NULL)
187 __blk_end_request_all(req, -ENODEV);
189 queue_work(dev->wq, &dev->work);
192 static int blktrans_open(struct block_device *bdev, fmode_t mode)
194 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
198 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
200 mutex_lock(&dev->lock);
206 __module_get(dev->tr->owner);
212 ret = dev->tr->open(dev);
217 ret = __get_mtd_device(dev->mtd);
220 dev->file_mode = mode;
224 mutex_unlock(&dev->lock);
225 blktrans_dev_put(dev);
229 if (dev->tr->release)
230 dev->tr->release(dev);
232 module_put(dev->tr->owner);
233 kref_put(&dev->ref, blktrans_dev_release);
234 mutex_unlock(&dev->lock);
235 blktrans_dev_put(dev);
239 static void blktrans_release(struct gendisk *disk, fmode_t mode)
241 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
246 mutex_lock(&dev->lock);
251 kref_put(&dev->ref, blktrans_dev_release);
252 module_put(dev->tr->owner);
255 if (dev->tr->release)
256 dev->tr->release(dev);
257 __put_mtd_device(dev->mtd);
260 mutex_unlock(&dev->lock);
261 blktrans_dev_put(dev);
264 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
266 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
272 mutex_lock(&dev->lock);
277 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
279 mutex_unlock(&dev->lock);
280 blktrans_dev_put(dev);
284 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
285 unsigned int cmd, unsigned long arg)
287 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
293 mutex_lock(&dev->lock);
300 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
306 mutex_unlock(&dev->lock);
307 blktrans_dev_put(dev);
311 static const struct block_device_operations mtd_block_ops = {
312 .owner = THIS_MODULE,
313 .open = blktrans_open,
314 .release = blktrans_release,
315 .ioctl = blktrans_ioctl,
316 .getgeo = blktrans_getgeo,
319 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
321 struct mtd_blktrans_ops *tr = new->tr;
322 struct mtd_blktrans_dev *d;
323 int last_devnum = -1;
327 if (mutex_trylock(&mtd_table_mutex)) {
328 mutex_unlock(&mtd_table_mutex);
332 mutex_lock(&blktrans_ref_mutex);
333 list_for_each_entry(d, &tr->devs, list) {
334 if (new->devnum == -1) {
335 /* Use first free number */
336 if (d->devnum != last_devnum+1) {
337 /* Found a free devnum. Plug it in here */
338 new->devnum = last_devnum+1;
339 list_add_tail(&new->list, &d->list);
342 } else if (d->devnum == new->devnum) {
343 /* Required number taken */
344 mutex_unlock(&blktrans_ref_mutex);
346 } else if (d->devnum > new->devnum) {
347 /* Required number was free */
348 list_add_tail(&new->list, &d->list);
351 last_devnum = d->devnum;
355 if (new->devnum == -1)
356 new->devnum = last_devnum+1;
358 /* Check that the device and any partitions will get valid
359 * minor numbers and that the disk naming code below can cope
360 * with this number. */
361 if (new->devnum > (MINORMASK >> tr->part_bits) ||
362 (tr->part_bits && new->devnum >= 27 * 26)) {
363 mutex_unlock(&blktrans_ref_mutex);
367 list_add_tail(&new->list, &tr->devs);
369 mutex_unlock(&blktrans_ref_mutex);
371 mutex_init(&new->lock);
372 kref_init(&new->ref);
378 gd = alloc_disk(1 << tr->part_bits);
384 gd->private_data = new;
385 gd->major = tr->major;
386 gd->first_minor = (new->devnum) << tr->part_bits;
387 gd->fops = &mtd_block_ops;
390 if (new->devnum < 26)
391 snprintf(gd->disk_name, sizeof(gd->disk_name),
392 "%s%c", tr->name, 'a' + new->devnum);
394 snprintf(gd->disk_name, sizeof(gd->disk_name),
396 'a' - 1 + new->devnum / 26,
397 'a' + new->devnum % 26);
399 snprintf(gd->disk_name, sizeof(gd->disk_name),
400 "%s%d", tr->name, new->devnum);
402 set_capacity(gd, (new->size * tr->blksize) >> 9);
404 /* Create the request queue */
405 spin_lock_init(&new->queue_lock);
406 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
411 new->rq->queuedata = new;
412 blk_queue_logical_block_size(new->rq, tr->blksize);
414 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
417 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
418 new->rq->limits.max_discard_sectors = UINT_MAX;
423 /* Create processing workqueue */
424 new->wq = alloc_workqueue("%s%d", 0, 0,
425 tr->name, new->mtd->index);
428 INIT_WORK(&new->work, mtd_blktrans_work);
430 gd->driverfs_dev = &new->mtd->dev;
437 if (new->disk_attributes) {
438 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
439 new->disk_attributes);
444 blk_cleanup_queue(new->rq);
448 list_del(&new->list);
453 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
457 if (mutex_trylock(&mtd_table_mutex)) {
458 mutex_unlock(&mtd_table_mutex);
462 if (old->disk_attributes)
463 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
464 old->disk_attributes);
466 /* Stop new requests to arrive */
467 del_gendisk(old->disk);
469 /* Stop workqueue. This will perform any pending request. */
470 destroy_workqueue(old->wq);
472 /* Kill current requests */
473 spin_lock_irqsave(&old->queue_lock, flags);
474 old->rq->queuedata = NULL;
475 blk_start_queue(old->rq);
476 spin_unlock_irqrestore(&old->queue_lock, flags);
478 /* If the device is currently open, tell trans driver to close it,
479 then put mtd device, and don't touch it again */
480 mutex_lock(&old->lock);
482 if (old->tr->release)
483 old->tr->release(old);
484 __put_mtd_device(old->mtd);
489 mutex_unlock(&old->lock);
490 blktrans_dev_put(old);
494 static void blktrans_notify_remove(struct mtd_info *mtd)
496 struct mtd_blktrans_ops *tr;
497 struct mtd_blktrans_dev *dev, *next;
499 list_for_each_entry(tr, &blktrans_majors, list)
500 list_for_each_entry_safe(dev, next, &tr->devs, list)
505 static void blktrans_notify_add(struct mtd_info *mtd)
507 struct mtd_blktrans_ops *tr;
509 if (mtd->type == MTD_ABSENT)
512 list_for_each_entry(tr, &blktrans_majors, list)
513 tr->add_mtd(tr, mtd);
516 static struct mtd_notifier blktrans_notifier = {
517 .add = blktrans_notify_add,
518 .remove = blktrans_notify_remove,
521 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
523 struct mtd_info *mtd;
526 /* Register the notifier if/when the first device type is
527 registered, to prevent the link/init ordering from fucking
529 if (!blktrans_notifier.list.next)
530 register_mtd_user(&blktrans_notifier);
533 mutex_lock(&mtd_table_mutex);
535 ret = register_blkdev(tr->major, tr->name);
537 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
538 tr->name, tr->major, ret);
539 mutex_unlock(&mtd_table_mutex);
546 tr->blkshift = ffs(tr->blksize) - 1;
548 INIT_LIST_HEAD(&tr->devs);
549 list_add(&tr->list, &blktrans_majors);
551 mtd_for_each_device(mtd)
552 if (mtd->type != MTD_ABSENT)
553 tr->add_mtd(tr, mtd);
555 mutex_unlock(&mtd_table_mutex);
559 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
561 struct mtd_blktrans_dev *dev, *next;
563 mutex_lock(&mtd_table_mutex);
565 /* Remove it from the list of active majors */
568 list_for_each_entry_safe(dev, next, &tr->devs, list)
571 unregister_blkdev(tr->major, tr->name);
572 mutex_unlock(&mtd_table_mutex);
574 BUG_ON(!list_empty(&tr->devs));
578 static void __exit mtd_blktrans_exit(void)
580 /* No race here -- if someone's currently in register_mtd_blktrans
581 we're screwed anyway. */
582 if (blktrans_notifier.list.next)
583 unregister_mtd_user(&blktrans_notifier);
586 module_exit(mtd_blktrans_exit);
588 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
589 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
590 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
591 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
593 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
594 MODULE_LICENSE("GPL");
595 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");