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/init.h>
34 #include <linux/mutex.h>
35 #include <asm/uaccess.h>
39 static LIST_HEAD(blktrans_majors);
40 static DEFINE_MUTEX(blktrans_ref_mutex);
42 static void blktrans_dev_release(struct kref *kref)
44 struct mtd_blktrans_dev *dev =
45 container_of(kref, struct mtd_blktrans_dev, ref);
47 dev->disk->private_data = NULL;
48 blk_cleanup_queue(dev->rq);
54 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
56 struct mtd_blktrans_dev *dev;
58 mutex_lock(&blktrans_ref_mutex);
59 dev = disk->private_data;
65 mutex_unlock(&blktrans_ref_mutex);
69 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
71 mutex_lock(&blktrans_ref_mutex);
72 kref_put(&dev->ref, blktrans_dev_release);
73 mutex_unlock(&blktrans_ref_mutex);
77 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
78 struct mtd_blktrans_dev *dev,
81 unsigned long block, nsect;
84 block = blk_rq_pos(req) << 9 >> tr->blkshift;
85 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
89 if (req->cmd_type != REQ_TYPE_FS)
92 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
93 get_capacity(req->rq_disk))
96 if (req->cmd_flags & REQ_DISCARD)
97 return tr->discard(dev, block, nsect);
99 switch(rq_data_dir(req)) {
101 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
102 if (tr->readsect(dev, block, buf))
104 rq_flush_dcache_pages(req);
110 rq_flush_dcache_pages(req);
111 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
112 if (tr->writesect(dev, block, buf))
116 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
121 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
125 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
127 static void mtd_blktrans_work(struct work_struct *work)
129 struct mtd_blktrans_dev *dev =
130 container_of(work, struct mtd_blktrans_dev, work);
131 struct mtd_blktrans_ops *tr = dev->tr;
132 struct request_queue *rq = dev->rq;
133 struct request *req = NULL;
134 int background_done = 0;
136 spin_lock_irq(rq->queue_lock);
141 dev->bg_stop = false;
142 if (!req && !(req = blk_fetch_request(rq))) {
143 if (tr->background && !background_done) {
144 spin_unlock_irq(rq->queue_lock);
145 mutex_lock(&dev->lock);
147 mutex_unlock(&dev->lock);
148 spin_lock_irq(rq->queue_lock);
150 * Do background processing just once per idle
153 background_done = !dev->bg_stop;
159 spin_unlock_irq(rq->queue_lock);
161 mutex_lock(&dev->lock);
162 res = do_blktrans_request(dev->tr, dev, req);
163 mutex_unlock(&dev->lock);
165 spin_lock_irq(rq->queue_lock);
167 if (!__blk_end_request_cur(req, res))
174 __blk_end_request_all(req, -EIO);
176 spin_unlock_irq(rq->queue_lock);
179 static void mtd_blktrans_request(struct request_queue *rq)
181 struct mtd_blktrans_dev *dev;
182 struct request *req = NULL;
187 while ((req = blk_fetch_request(rq)) != NULL)
188 __blk_end_request_all(req, -ENODEV);
190 queue_work(dev->wq, &dev->work);
193 static int blktrans_open(struct block_device *bdev, fmode_t mode)
195 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
199 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
201 mutex_lock(&dev->lock);
202 mutex_lock(&mtd_table_mutex);
208 __module_get(dev->tr->owner);
214 ret = dev->tr->open(dev);
219 ret = __get_mtd_device(dev->mtd);
222 dev->file_mode = mode;
226 mutex_unlock(&mtd_table_mutex);
227 mutex_unlock(&dev->lock);
228 blktrans_dev_put(dev);
232 if (dev->tr->release)
233 dev->tr->release(dev);
235 module_put(dev->tr->owner);
236 kref_put(&dev->ref, blktrans_dev_release);
237 mutex_unlock(&mtd_table_mutex);
238 mutex_unlock(&dev->lock);
239 blktrans_dev_put(dev);
243 static void blktrans_release(struct gendisk *disk, fmode_t mode)
245 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
250 mutex_lock(&dev->lock);
251 mutex_lock(&mtd_table_mutex);
256 kref_put(&dev->ref, blktrans_dev_release);
257 module_put(dev->tr->owner);
260 if (dev->tr->release)
261 dev->tr->release(dev);
262 __put_mtd_device(dev->mtd);
265 mutex_unlock(&mtd_table_mutex);
266 mutex_unlock(&dev->lock);
267 blktrans_dev_put(dev);
270 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
272 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
278 mutex_lock(&dev->lock);
283 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
285 mutex_unlock(&dev->lock);
286 blktrans_dev_put(dev);
290 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
291 unsigned int cmd, unsigned long arg)
293 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
299 mutex_lock(&dev->lock);
306 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
312 mutex_unlock(&dev->lock);
313 blktrans_dev_put(dev);
317 static const struct block_device_operations mtd_block_ops = {
318 .owner = THIS_MODULE,
319 .open = blktrans_open,
320 .release = blktrans_release,
321 .ioctl = blktrans_ioctl,
322 .getgeo = blktrans_getgeo,
325 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
327 struct mtd_blktrans_ops *tr = new->tr;
328 struct mtd_blktrans_dev *d;
329 int last_devnum = -1;
333 if (mutex_trylock(&mtd_table_mutex)) {
334 mutex_unlock(&mtd_table_mutex);
338 mutex_lock(&blktrans_ref_mutex);
339 list_for_each_entry(d, &tr->devs, list) {
340 if (new->devnum == -1) {
341 /* Use first free number */
342 if (d->devnum != last_devnum+1) {
343 /* Found a free devnum. Plug it in here */
344 new->devnum = last_devnum+1;
345 list_add_tail(&new->list, &d->list);
348 } else if (d->devnum == new->devnum) {
349 /* Required number taken */
350 mutex_unlock(&blktrans_ref_mutex);
352 } else if (d->devnum > new->devnum) {
353 /* Required number was free */
354 list_add_tail(&new->list, &d->list);
357 last_devnum = d->devnum;
361 if (new->devnum == -1)
362 new->devnum = last_devnum+1;
364 /* Check that the device and any partitions will get valid
365 * minor numbers and that the disk naming code below can cope
366 * with this number. */
367 if (new->devnum > (MINORMASK >> tr->part_bits) ||
368 (tr->part_bits && new->devnum >= 27 * 26)) {
369 mutex_unlock(&blktrans_ref_mutex);
373 list_add_tail(&new->list, &tr->devs);
375 mutex_unlock(&blktrans_ref_mutex);
377 mutex_init(&new->lock);
378 kref_init(&new->ref);
384 gd = alloc_disk(1 << tr->part_bits);
390 gd->private_data = new;
391 gd->major = tr->major;
392 gd->first_minor = (new->devnum) << tr->part_bits;
393 gd->fops = &mtd_block_ops;
396 if (new->devnum < 26)
397 snprintf(gd->disk_name, sizeof(gd->disk_name),
398 "%s%c", tr->name, 'a' + new->devnum);
400 snprintf(gd->disk_name, sizeof(gd->disk_name),
402 'a' - 1 + new->devnum / 26,
403 'a' + new->devnum % 26);
405 snprintf(gd->disk_name, sizeof(gd->disk_name),
406 "%s%d", tr->name, new->devnum);
408 set_capacity(gd, (new->size * tr->blksize) >> 9);
410 /* Create the request queue */
411 spin_lock_init(&new->queue_lock);
412 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
417 new->rq->queuedata = new;
418 blk_queue_logical_block_size(new->rq, tr->blksize);
420 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
423 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
424 new->rq->limits.max_discard_sectors = UINT_MAX;
429 /* Create processing workqueue */
430 new->wq = alloc_workqueue("%s%d", 0, 0,
431 tr->name, new->mtd->index);
434 INIT_WORK(&new->work, mtd_blktrans_work);
436 gd->driverfs_dev = &new->mtd->dev;
443 if (new->disk_attributes) {
444 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
445 new->disk_attributes);
450 blk_cleanup_queue(new->rq);
454 list_del(&new->list);
459 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
463 if (mutex_trylock(&mtd_table_mutex)) {
464 mutex_unlock(&mtd_table_mutex);
468 if (old->disk_attributes)
469 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
470 old->disk_attributes);
472 /* Stop new requests to arrive */
473 del_gendisk(old->disk);
475 /* Stop workqueue. This will perform any pending request. */
476 destroy_workqueue(old->wq);
478 /* Kill current requests */
479 spin_lock_irqsave(&old->queue_lock, flags);
480 old->rq->queuedata = NULL;
481 blk_start_queue(old->rq);
482 spin_unlock_irqrestore(&old->queue_lock, flags);
484 /* If the device is currently open, tell trans driver to close it,
485 then put mtd device, and don't touch it again */
486 mutex_lock(&old->lock);
488 if (old->tr->release)
489 old->tr->release(old);
490 __put_mtd_device(old->mtd);
495 mutex_unlock(&old->lock);
496 blktrans_dev_put(old);
500 static void blktrans_notify_remove(struct mtd_info *mtd)
502 struct mtd_blktrans_ops *tr;
503 struct mtd_blktrans_dev *dev, *next;
505 list_for_each_entry(tr, &blktrans_majors, list)
506 list_for_each_entry_safe(dev, next, &tr->devs, list)
511 static void blktrans_notify_add(struct mtd_info *mtd)
513 struct mtd_blktrans_ops *tr;
515 if (mtd->type == MTD_ABSENT)
518 list_for_each_entry(tr, &blktrans_majors, list)
519 tr->add_mtd(tr, mtd);
522 static struct mtd_notifier blktrans_notifier = {
523 .add = blktrans_notify_add,
524 .remove = blktrans_notify_remove,
527 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
529 struct mtd_info *mtd;
532 /* Register the notifier if/when the first device type is
533 registered, to prevent the link/init ordering from fucking
535 if (!blktrans_notifier.list.next)
536 register_mtd_user(&blktrans_notifier);
539 mutex_lock(&mtd_table_mutex);
541 ret = register_blkdev(tr->major, tr->name);
543 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
544 tr->name, tr->major, ret);
545 mutex_unlock(&mtd_table_mutex);
552 tr->blkshift = ffs(tr->blksize) - 1;
554 INIT_LIST_HEAD(&tr->devs);
555 list_add(&tr->list, &blktrans_majors);
557 mtd_for_each_device(mtd)
558 if (mtd->type != MTD_ABSENT)
559 tr->add_mtd(tr, mtd);
561 mutex_unlock(&mtd_table_mutex);
565 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
567 struct mtd_blktrans_dev *dev, *next;
569 mutex_lock(&mtd_table_mutex);
571 /* Remove it from the list of active majors */
574 list_for_each_entry_safe(dev, next, &tr->devs, list)
577 unregister_blkdev(tr->major, tr->name);
578 mutex_unlock(&mtd_table_mutex);
580 BUG_ON(!list_empty(&tr->devs));
584 static void __exit mtd_blktrans_exit(void)
586 /* No race here -- if someone's currently in register_mtd_blktrans
587 we're screwed anyway. */
588 if (blktrans_notifier.list.next)
589 unregister_mtd_user(&blktrans_notifier);
592 module_exit(mtd_blktrans_exit);
594 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
595 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
596 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
597 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
599 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
600 MODULE_LICENSE("GPL");
601 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");