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;
85 buf = bio_data(req->bio);
87 if (req->cmd_type != REQ_TYPE_FS)
90 if (req->cmd_flags & REQ_FLUSH)
91 return tr->flush(dev);
93 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
94 get_capacity(req->rq_disk))
97 if (req->cmd_flags & REQ_DISCARD)
98 return tr->discard(dev, block, nsect);
100 switch(rq_data_dir(req)) {
102 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
103 if (tr->readsect(dev, block, buf))
105 rq_flush_dcache_pages(req);
111 rq_flush_dcache_pages(req);
112 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
113 if (tr->writesect(dev, block, buf))
117 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
122 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
126 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
128 static void mtd_blktrans_work(struct work_struct *work)
130 struct mtd_blktrans_dev *dev =
131 container_of(work, struct mtd_blktrans_dev, work);
132 struct mtd_blktrans_ops *tr = dev->tr;
133 struct request_queue *rq = dev->rq;
134 struct request *req = NULL;
135 int background_done = 0;
137 spin_lock_irq(rq->queue_lock);
142 dev->bg_stop = false;
143 if (!req && !(req = blk_fetch_request(rq))) {
144 if (tr->background && !background_done) {
145 spin_unlock_irq(rq->queue_lock);
146 mutex_lock(&dev->lock);
148 mutex_unlock(&dev->lock);
149 spin_lock_irq(rq->queue_lock);
151 * Do background processing just once per idle
154 background_done = !dev->bg_stop;
160 spin_unlock_irq(rq->queue_lock);
162 mutex_lock(&dev->lock);
163 res = do_blktrans_request(dev->tr, dev, req);
164 mutex_unlock(&dev->lock);
166 spin_lock_irq(rq->queue_lock);
168 if (!__blk_end_request_cur(req, res))
174 spin_unlock_irq(rq->queue_lock);
177 static void mtd_blktrans_request(struct request_queue *rq)
179 struct mtd_blktrans_dev *dev;
180 struct request *req = NULL;
185 while ((req = blk_fetch_request(rq)) != NULL)
186 __blk_end_request_all(req, -ENODEV);
188 queue_work(dev->wq, &dev->work);
191 static int blktrans_open(struct block_device *bdev, fmode_t mode)
193 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
197 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
199 mutex_lock(&dev->lock);
200 mutex_lock(&mtd_table_mutex);
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(&mtd_table_mutex);
225 mutex_unlock(&dev->lock);
226 blktrans_dev_put(dev);
230 if (dev->tr->release)
231 dev->tr->release(dev);
233 module_put(dev->tr->owner);
234 kref_put(&dev->ref, blktrans_dev_release);
235 mutex_unlock(&mtd_table_mutex);
236 mutex_unlock(&dev->lock);
237 blktrans_dev_put(dev);
241 static void blktrans_release(struct gendisk *disk, fmode_t mode)
243 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
248 mutex_lock(&dev->lock);
249 mutex_lock(&mtd_table_mutex);
254 kref_put(&dev->ref, blktrans_dev_release);
255 module_put(dev->tr->owner);
258 if (dev->tr->release)
259 dev->tr->release(dev);
260 __put_mtd_device(dev->mtd);
263 mutex_unlock(&mtd_table_mutex);
264 mutex_unlock(&dev->lock);
265 blktrans_dev_put(dev);
268 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
270 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
276 mutex_lock(&dev->lock);
281 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
283 mutex_unlock(&dev->lock);
284 blktrans_dev_put(dev);
288 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
289 unsigned int cmd, unsigned long arg)
291 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
297 mutex_lock(&dev->lock);
304 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
310 mutex_unlock(&dev->lock);
311 blktrans_dev_put(dev);
315 static const struct block_device_operations mtd_block_ops = {
316 .owner = THIS_MODULE,
317 .open = blktrans_open,
318 .release = blktrans_release,
319 .ioctl = blktrans_ioctl,
320 .getgeo = blktrans_getgeo,
323 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
325 struct mtd_blktrans_ops *tr = new->tr;
326 struct mtd_blktrans_dev *d;
327 int last_devnum = -1;
331 if (mutex_trylock(&mtd_table_mutex)) {
332 mutex_unlock(&mtd_table_mutex);
336 mutex_lock(&blktrans_ref_mutex);
337 list_for_each_entry(d, &tr->devs, list) {
338 if (new->devnum == -1) {
339 /* Use first free number */
340 if (d->devnum != last_devnum+1) {
341 /* Found a free devnum. Plug it in here */
342 new->devnum = last_devnum+1;
343 list_add_tail(&new->list, &d->list);
346 } else if (d->devnum == new->devnum) {
347 /* Required number taken */
348 mutex_unlock(&blktrans_ref_mutex);
350 } else if (d->devnum > new->devnum) {
351 /* Required number was free */
352 list_add_tail(&new->list, &d->list);
355 last_devnum = d->devnum;
359 if (new->devnum == -1)
360 new->devnum = last_devnum+1;
362 /* Check that the device and any partitions will get valid
363 * minor numbers and that the disk naming code below can cope
364 * with this number. */
365 if (new->devnum > (MINORMASK >> tr->part_bits) ||
366 (tr->part_bits && new->devnum >= 27 * 26)) {
367 mutex_unlock(&blktrans_ref_mutex);
371 list_add_tail(&new->list, &tr->devs);
373 mutex_unlock(&blktrans_ref_mutex);
375 mutex_init(&new->lock);
376 kref_init(&new->ref);
382 gd = alloc_disk(1 << tr->part_bits);
388 gd->private_data = new;
389 gd->major = tr->major;
390 gd->first_minor = (new->devnum) << tr->part_bits;
391 gd->fops = &mtd_block_ops;
394 if (new->devnum < 26)
395 snprintf(gd->disk_name, sizeof(gd->disk_name),
396 "%s%c", tr->name, 'a' + new->devnum);
398 snprintf(gd->disk_name, sizeof(gd->disk_name),
400 'a' - 1 + new->devnum / 26,
401 'a' + new->devnum % 26);
403 snprintf(gd->disk_name, sizeof(gd->disk_name),
404 "%s%d", tr->name, new->devnum);
406 set_capacity(gd, (new->size * tr->blksize) >> 9);
408 /* Create the request queue */
409 spin_lock_init(&new->queue_lock);
410 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
416 blk_queue_flush(new->rq, REQ_FLUSH);
418 new->rq->queuedata = new;
419 blk_queue_logical_block_size(new->rq, tr->blksize);
421 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
422 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
425 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
426 new->rq->limits.max_discard_sectors = UINT_MAX;
431 /* Create processing workqueue */
432 new->wq = alloc_workqueue("%s%d", 0, 0,
433 tr->name, new->mtd->index);
436 INIT_WORK(&new->work, mtd_blktrans_work);
438 gd->driverfs_dev = &new->mtd->dev;
445 if (new->disk_attributes) {
446 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
447 new->disk_attributes);
452 blk_cleanup_queue(new->rq);
456 list_del(&new->list);
461 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
465 if (mutex_trylock(&mtd_table_mutex)) {
466 mutex_unlock(&mtd_table_mutex);
470 if (old->disk_attributes)
471 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
472 old->disk_attributes);
474 /* Stop new requests to arrive */
475 del_gendisk(old->disk);
477 /* Stop workqueue. This will perform any pending request. */
478 destroy_workqueue(old->wq);
480 /* Kill current requests */
481 spin_lock_irqsave(&old->queue_lock, flags);
482 old->rq->queuedata = NULL;
483 blk_start_queue(old->rq);
484 spin_unlock_irqrestore(&old->queue_lock, flags);
486 /* If the device is currently open, tell trans driver to close it,
487 then put mtd device, and don't touch it again */
488 mutex_lock(&old->lock);
490 if (old->tr->release)
491 old->tr->release(old);
492 __put_mtd_device(old->mtd);
497 mutex_unlock(&old->lock);
498 blktrans_dev_put(old);
502 static void blktrans_notify_remove(struct mtd_info *mtd)
504 struct mtd_blktrans_ops *tr;
505 struct mtd_blktrans_dev *dev, *next;
507 list_for_each_entry(tr, &blktrans_majors, list)
508 list_for_each_entry_safe(dev, next, &tr->devs, list)
513 static void blktrans_notify_add(struct mtd_info *mtd)
515 struct mtd_blktrans_ops *tr;
517 if (mtd->type == MTD_ABSENT)
520 list_for_each_entry(tr, &blktrans_majors, list)
521 tr->add_mtd(tr, mtd);
524 static struct mtd_notifier blktrans_notifier = {
525 .add = blktrans_notify_add,
526 .remove = blktrans_notify_remove,
529 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
531 struct mtd_info *mtd;
534 /* Register the notifier if/when the first device type is
535 registered, to prevent the link/init ordering from fucking
537 if (!blktrans_notifier.list.next)
538 register_mtd_user(&blktrans_notifier);
541 mutex_lock(&mtd_table_mutex);
543 ret = register_blkdev(tr->major, tr->name);
545 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
546 tr->name, tr->major, ret);
547 mutex_unlock(&mtd_table_mutex);
554 tr->blkshift = ffs(tr->blksize) - 1;
556 INIT_LIST_HEAD(&tr->devs);
557 list_add(&tr->list, &blktrans_majors);
559 mtd_for_each_device(mtd)
560 if (mtd->type != MTD_ABSENT)
561 tr->add_mtd(tr, mtd);
563 mutex_unlock(&mtd_table_mutex);
567 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
569 struct mtd_blktrans_dev *dev, *next;
571 mutex_lock(&mtd_table_mutex);
573 /* Remove it from the list of active majors */
576 list_for_each_entry_safe(dev, next, &tr->devs, list)
579 unregister_blkdev(tr->major, tr->name);
580 mutex_unlock(&mtd_table_mutex);
582 BUG_ON(!list_empty(&tr->devs));
586 static void __exit mtd_blktrans_exit(void)
588 /* No race here -- if someone's currently in register_mtd_blktrans
589 we're screwed anyway. */
590 if (blktrans_notifier.list.next)
591 unregister_mtd_user(&blktrans_notifier);
594 module_exit(mtd_blktrans_exit);
596 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
597 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
598 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
599 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
601 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
602 MODULE_LICENSE("GPL");
603 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");