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 (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
91 get_capacity(req->rq_disk))
94 if (req->cmd_flags & REQ_DISCARD)
95 return tr->discard(dev, block, nsect);
97 switch(rq_data_dir(req)) {
99 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
100 if (tr->readsect(dev, block, buf))
102 rq_flush_dcache_pages(req);
108 rq_flush_dcache_pages(req);
109 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
110 if (tr->writesect(dev, block, buf))
114 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
119 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
123 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
125 static void mtd_blktrans_work(struct work_struct *work)
127 struct mtd_blktrans_dev *dev =
128 container_of(work, struct mtd_blktrans_dev, work);
129 struct mtd_blktrans_ops *tr = dev->tr;
130 struct request_queue *rq = dev->rq;
131 struct request *req = NULL;
132 int background_done = 0;
134 spin_lock_irq(rq->queue_lock);
139 dev->bg_stop = false;
140 if (!req && !(req = blk_fetch_request(rq))) {
141 if (tr->background && !background_done) {
142 spin_unlock_irq(rq->queue_lock);
143 mutex_lock(&dev->lock);
145 mutex_unlock(&dev->lock);
146 spin_lock_irq(rq->queue_lock);
148 * Do background processing just once per idle
151 background_done = !dev->bg_stop;
157 spin_unlock_irq(rq->queue_lock);
159 mutex_lock(&dev->lock);
160 res = do_blktrans_request(dev->tr, dev, req);
161 mutex_unlock(&dev->lock);
163 spin_lock_irq(rq->queue_lock);
165 if (!__blk_end_request_cur(req, res))
172 __blk_end_request_all(req, -EIO);
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);
205 __module_get(dev->tr->owner);
211 ret = dev->tr->open(dev);
216 ret = __get_mtd_device(dev->mtd);
219 dev->file_mode = mode;
223 mutex_unlock(&dev->lock);
224 blktrans_dev_put(dev);
228 if (dev->tr->release)
229 dev->tr->release(dev);
231 module_put(dev->tr->owner);
232 kref_put(&dev->ref, blktrans_dev_release);
233 mutex_unlock(&dev->lock);
234 blktrans_dev_put(dev);
238 static void blktrans_release(struct gendisk *disk, fmode_t mode)
240 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
245 mutex_lock(&dev->lock);
250 kref_put(&dev->ref, blktrans_dev_release);
251 module_put(dev->tr->owner);
254 if (dev->tr->release)
255 dev->tr->release(dev);
256 __put_mtd_device(dev->mtd);
259 mutex_unlock(&dev->lock);
260 blktrans_dev_put(dev);
263 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
265 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
271 mutex_lock(&dev->lock);
276 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
278 mutex_unlock(&dev->lock);
279 blktrans_dev_put(dev);
283 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
284 unsigned int cmd, unsigned long arg)
286 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
292 mutex_lock(&dev->lock);
299 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
305 mutex_unlock(&dev->lock);
306 blktrans_dev_put(dev);
310 static const struct block_device_operations mtd_block_ops = {
311 .owner = THIS_MODULE,
312 .open = blktrans_open,
313 .release = blktrans_release,
314 .ioctl = blktrans_ioctl,
315 .getgeo = blktrans_getgeo,
318 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
320 struct mtd_blktrans_ops *tr = new->tr;
321 struct mtd_blktrans_dev *d;
322 int last_devnum = -1;
326 if (mutex_trylock(&mtd_table_mutex)) {
327 mutex_unlock(&mtd_table_mutex);
331 mutex_lock(&blktrans_ref_mutex);
332 list_for_each_entry(d, &tr->devs, list) {
333 if (new->devnum == -1) {
334 /* Use first free number */
335 if (d->devnum != last_devnum+1) {
336 /* Found a free devnum. Plug it in here */
337 new->devnum = last_devnum+1;
338 list_add_tail(&new->list, &d->list);
341 } else if (d->devnum == new->devnum) {
342 /* Required number taken */
343 mutex_unlock(&blktrans_ref_mutex);
345 } else if (d->devnum > new->devnum) {
346 /* Required number was free */
347 list_add_tail(&new->list, &d->list);
350 last_devnum = d->devnum;
354 if (new->devnum == -1)
355 new->devnum = last_devnum+1;
357 /* Check that the device and any partitions will get valid
358 * minor numbers and that the disk naming code below can cope
359 * with this number. */
360 if (new->devnum > (MINORMASK >> tr->part_bits) ||
361 (tr->part_bits && new->devnum >= 27 * 26)) {
362 mutex_unlock(&blktrans_ref_mutex);
366 list_add_tail(&new->list, &tr->devs);
368 mutex_unlock(&blktrans_ref_mutex);
370 mutex_init(&new->lock);
371 kref_init(&new->ref);
377 gd = alloc_disk(1 << tr->part_bits);
383 gd->private_data = new;
384 gd->major = tr->major;
385 gd->first_minor = (new->devnum) << tr->part_bits;
386 gd->fops = &mtd_block_ops;
389 if (new->devnum < 26)
390 snprintf(gd->disk_name, sizeof(gd->disk_name),
391 "%s%c", tr->name, 'a' + new->devnum);
393 snprintf(gd->disk_name, sizeof(gd->disk_name),
395 'a' - 1 + new->devnum / 26,
396 'a' + new->devnum % 26);
398 snprintf(gd->disk_name, sizeof(gd->disk_name),
399 "%s%d", tr->name, new->devnum);
401 set_capacity(gd, (new->size * tr->blksize) >> 9);
403 /* Create the request queue */
404 spin_lock_init(&new->queue_lock);
405 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
410 new->rq->queuedata = new;
411 blk_queue_logical_block_size(new->rq, tr->blksize);
413 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
416 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
417 new->rq->limits.max_discard_sectors = UINT_MAX;
422 /* Create processing workqueue */
423 new->wq = alloc_workqueue("%s%d", 0, 0,
424 tr->name, new->mtd->index);
427 INIT_WORK(&new->work, mtd_blktrans_work);
429 gd->driverfs_dev = &new->mtd->dev;
436 if (new->disk_attributes) {
437 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
438 new->disk_attributes);
443 blk_cleanup_queue(new->rq);
447 list_del(&new->list);
452 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
456 if (mutex_trylock(&mtd_table_mutex)) {
457 mutex_unlock(&mtd_table_mutex);
461 if (old->disk_attributes)
462 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
463 old->disk_attributes);
465 /* Stop new requests to arrive */
466 del_gendisk(old->disk);
468 /* Stop workqueue. This will perform any pending request. */
469 destroy_workqueue(old->wq);
471 /* Kill current requests */
472 spin_lock_irqsave(&old->queue_lock, flags);
473 old->rq->queuedata = NULL;
474 blk_start_queue(old->rq);
475 spin_unlock_irqrestore(&old->queue_lock, flags);
477 /* If the device is currently open, tell trans driver to close it,
478 then put mtd device, and don't touch it again */
479 mutex_lock(&old->lock);
481 if (old->tr->release)
482 old->tr->release(old);
483 __put_mtd_device(old->mtd);
488 mutex_unlock(&old->lock);
489 blktrans_dev_put(old);
493 static void blktrans_notify_remove(struct mtd_info *mtd)
495 struct mtd_blktrans_ops *tr;
496 struct mtd_blktrans_dev *dev, *next;
498 list_for_each_entry(tr, &blktrans_majors, list)
499 list_for_each_entry_safe(dev, next, &tr->devs, list)
504 static void blktrans_notify_add(struct mtd_info *mtd)
506 struct mtd_blktrans_ops *tr;
508 if (mtd->type == MTD_ABSENT)
511 list_for_each_entry(tr, &blktrans_majors, list)
512 tr->add_mtd(tr, mtd);
515 static struct mtd_notifier blktrans_notifier = {
516 .add = blktrans_notify_add,
517 .remove = blktrans_notify_remove,
520 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
522 struct mtd_info *mtd;
525 /* Register the notifier if/when the first device type is
526 registered, to prevent the link/init ordering from fucking
528 if (!blktrans_notifier.list.next)
529 register_mtd_user(&blktrans_notifier);
532 mutex_lock(&mtd_table_mutex);
534 ret = register_blkdev(tr->major, tr->name);
536 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
537 tr->name, tr->major, ret);
538 mutex_unlock(&mtd_table_mutex);
545 tr->blkshift = ffs(tr->blksize) - 1;
547 INIT_LIST_HEAD(&tr->devs);
548 list_add(&tr->list, &blktrans_majors);
550 mtd_for_each_device(mtd)
551 if (mtd->type != MTD_ABSENT)
552 tr->add_mtd(tr, mtd);
554 mutex_unlock(&mtd_table_mutex);
558 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
560 struct mtd_blktrans_dev *dev, *next;
562 mutex_lock(&mtd_table_mutex);
564 /* Remove it from the list of active majors */
567 list_for_each_entry_safe(dev, next, &tr->devs, list)
570 unregister_blkdev(tr->major, tr->name);
571 mutex_unlock(&mtd_table_mutex);
573 BUG_ON(!list_empty(&tr->devs));
577 static void __exit mtd_blktrans_exit(void)
579 /* No race here -- if someone's currently in register_mtd_blktrans
580 we're screwed anyway. */
581 if (blktrans_notifier.list.next)
582 unregister_mtd_user(&blktrans_notifier);
585 module_exit(mtd_blktrans_exit);
587 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
588 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
589 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
590 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
592 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
593 MODULE_LICENSE("GPL");
594 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");