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 <linux/kthread.h>
36 #include <asm/uaccess.h>
40 static LIST_HEAD(blktrans_majors);
41 static DEFINE_MUTEX(blktrans_ref_mutex);
43 static void blktrans_dev_release(struct kref *kref)
45 struct mtd_blktrans_dev *dev =
46 container_of(kref, struct mtd_blktrans_dev, ref);
48 dev->disk->private_data = NULL;
49 blk_cleanup_queue(dev->rq);
55 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
57 struct mtd_blktrans_dev *dev;
59 mutex_lock(&blktrans_ref_mutex);
60 dev = disk->private_data;
66 mutex_unlock(&blktrans_ref_mutex);
70 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
72 mutex_lock(&blktrans_ref_mutex);
73 kref_put(&dev->ref, blktrans_dev_release);
74 mutex_unlock(&blktrans_ref_mutex);
78 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
79 struct mtd_blktrans_dev *dev,
82 unsigned long block, nsect;
85 block = blk_rq_pos(req) << 9 >> tr->blkshift;
86 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
90 if (req->cmd_type != REQ_TYPE_FS)
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)
124 if (kthread_should_stop())
129 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
131 static int mtd_blktrans_thread(void *arg)
133 struct mtd_blktrans_dev *dev = arg;
134 struct mtd_blktrans_ops *tr = dev->tr;
135 struct request_queue *rq = dev->rq;
136 struct request *req = NULL;
137 int background_done = 0;
139 spin_lock_irq(rq->queue_lock);
141 while (!kthread_should_stop()) {
144 dev->bg_stop = false;
145 if (!req && !(req = blk_fetch_request(rq))) {
146 if (tr->background && !background_done) {
147 spin_unlock_irq(rq->queue_lock);
148 mutex_lock(&dev->lock);
150 mutex_unlock(&dev->lock);
151 spin_lock_irq(rq->queue_lock);
153 * Do background processing just once per idle
156 background_done = !dev->bg_stop;
159 set_current_state(TASK_INTERRUPTIBLE);
161 if (kthread_should_stop())
162 set_current_state(TASK_RUNNING);
164 spin_unlock_irq(rq->queue_lock);
166 spin_lock_irq(rq->queue_lock);
170 spin_unlock_irq(rq->queue_lock);
172 mutex_lock(&dev->lock);
173 res = do_blktrans_request(dev->tr, dev, req);
174 mutex_unlock(&dev->lock);
176 spin_lock_irq(rq->queue_lock);
178 if (!__blk_end_request_cur(req, res))
185 __blk_end_request_all(req, -EIO);
187 spin_unlock_irq(rq->queue_lock);
192 static void mtd_blktrans_request(struct request_queue *rq)
194 struct mtd_blktrans_dev *dev;
195 struct request *req = NULL;
200 while ((req = blk_fetch_request(rq)) != NULL)
201 __blk_end_request_all(req, -ENODEV);
204 wake_up_process(dev->thread);
208 static int blktrans_open(struct block_device *bdev, fmode_t mode)
210 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
214 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
216 mutex_lock(&dev->lock);
222 __module_get(dev->tr->owner);
228 ret = dev->tr->open(dev);
233 ret = __get_mtd_device(dev->mtd);
238 mutex_unlock(&dev->lock);
239 blktrans_dev_put(dev);
243 if (dev->tr->release)
244 dev->tr->release(dev);
246 module_put(dev->tr->owner);
247 kref_put(&dev->ref, blktrans_dev_release);
248 mutex_unlock(&dev->lock);
249 blktrans_dev_put(dev);
253 static int blktrans_release(struct gendisk *disk, fmode_t mode)
255 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
261 mutex_lock(&dev->lock);
266 kref_put(&dev->ref, blktrans_dev_release);
267 module_put(dev->tr->owner);
270 ret = dev->tr->release ? dev->tr->release(dev) : 0;
271 __put_mtd_device(dev->mtd);
274 mutex_unlock(&dev->lock);
275 blktrans_dev_put(dev);
279 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
281 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
287 mutex_lock(&dev->lock);
292 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
294 mutex_unlock(&dev->lock);
295 blktrans_dev_put(dev);
299 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
300 unsigned int cmd, unsigned long arg)
302 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
308 mutex_lock(&dev->lock);
315 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
321 mutex_unlock(&dev->lock);
322 blktrans_dev_put(dev);
326 static const struct block_device_operations mtd_blktrans_ops = {
327 .owner = THIS_MODULE,
328 .open = blktrans_open,
329 .release = blktrans_release,
330 .ioctl = blktrans_ioctl,
331 .getgeo = blktrans_getgeo,
334 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
336 struct mtd_blktrans_ops *tr = new->tr;
337 struct mtd_blktrans_dev *d;
338 int last_devnum = -1;
342 if (mutex_trylock(&mtd_table_mutex)) {
343 mutex_unlock(&mtd_table_mutex);
347 mutex_lock(&blktrans_ref_mutex);
348 list_for_each_entry(d, &tr->devs, list) {
349 if (new->devnum == -1) {
350 /* Use first free number */
351 if (d->devnum != last_devnum+1) {
352 /* Found a free devnum. Plug it in here */
353 new->devnum = last_devnum+1;
354 list_add_tail(&new->list, &d->list);
357 } else if (d->devnum == new->devnum) {
358 /* Required number taken */
359 mutex_unlock(&blktrans_ref_mutex);
361 } else if (d->devnum > new->devnum) {
362 /* Required number was free */
363 list_add_tail(&new->list, &d->list);
366 last_devnum = d->devnum;
370 if (new->devnum == -1)
371 new->devnum = last_devnum+1;
373 /* Check that the device and any partitions will get valid
374 * minor numbers and that the disk naming code below can cope
375 * with this number. */
376 if (new->devnum > (MINORMASK >> tr->part_bits) ||
377 (tr->part_bits && new->devnum >= 27 * 26)) {
378 mutex_unlock(&blktrans_ref_mutex);
382 list_add_tail(&new->list, &tr->devs);
384 mutex_unlock(&blktrans_ref_mutex);
386 mutex_init(&new->lock);
387 kref_init(&new->ref);
393 gd = alloc_disk(1 << tr->part_bits);
399 gd->private_data = new;
400 gd->major = tr->major;
401 gd->first_minor = (new->devnum) << tr->part_bits;
402 gd->fops = &mtd_blktrans_ops;
405 if (new->devnum < 26)
406 snprintf(gd->disk_name, sizeof(gd->disk_name),
407 "%s%c", tr->name, 'a' + new->devnum);
409 snprintf(gd->disk_name, sizeof(gd->disk_name),
411 'a' - 1 + new->devnum / 26,
412 'a' + new->devnum % 26);
414 snprintf(gd->disk_name, sizeof(gd->disk_name),
415 "%s%d", tr->name, new->devnum);
417 set_capacity(gd, (new->size * tr->blksize) >> 9);
419 /* Create the request queue */
420 spin_lock_init(&new->queue_lock);
421 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
426 new->rq->queuedata = new;
427 blk_queue_logical_block_size(new->rq, tr->blksize);
429 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
432 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
433 new->rq->limits.max_discard_sectors = UINT_MAX;
438 /* Create processing thread */
439 /* TODO: workqueue ? */
440 new->thread = kthread_run(mtd_blktrans_thread, new,
441 "%s%d", tr->name, new->mtd->index);
442 if (IS_ERR(new->thread)) {
443 ret = PTR_ERR(new->thread);
446 gd->driverfs_dev = &new->mtd->dev;
453 if (new->disk_attributes) {
454 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
455 new->disk_attributes);
460 blk_cleanup_queue(new->rq);
464 list_del(&new->list);
469 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
473 if (mutex_trylock(&mtd_table_mutex)) {
474 mutex_unlock(&mtd_table_mutex);
478 if (old->disk_attributes)
479 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
480 old->disk_attributes);
482 /* Stop new requests to arrive */
483 del_gendisk(old->disk);
486 /* Stop the thread */
487 kthread_stop(old->thread);
489 /* Kill current requests */
490 spin_lock_irqsave(&old->queue_lock, flags);
491 old->rq->queuedata = NULL;
492 blk_start_queue(old->rq);
493 spin_unlock_irqrestore(&old->queue_lock, flags);
495 /* If the device is currently open, tell trans driver to close it,
496 then put mtd device, and don't touch it again */
497 mutex_lock(&old->lock);
499 if (old->tr->release)
500 old->tr->release(old);
501 __put_mtd_device(old->mtd);
506 mutex_unlock(&old->lock);
507 blktrans_dev_put(old);
511 static void blktrans_notify_remove(struct mtd_info *mtd)
513 struct mtd_blktrans_ops *tr;
514 struct mtd_blktrans_dev *dev, *next;
516 list_for_each_entry(tr, &blktrans_majors, list)
517 list_for_each_entry_safe(dev, next, &tr->devs, list)
522 static void blktrans_notify_add(struct mtd_info *mtd)
524 struct mtd_blktrans_ops *tr;
526 if (mtd->type == MTD_ABSENT)
529 list_for_each_entry(tr, &blktrans_majors, list)
530 tr->add_mtd(tr, mtd);
533 static struct mtd_notifier blktrans_notifier = {
534 .add = blktrans_notify_add,
535 .remove = blktrans_notify_remove,
538 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
540 struct mtd_info *mtd;
543 /* Register the notifier if/when the first device type is
544 registered, to prevent the link/init ordering from fucking
546 if (!blktrans_notifier.list.next)
547 register_mtd_user(&blktrans_notifier);
550 mutex_lock(&mtd_table_mutex);
552 ret = register_blkdev(tr->major, tr->name);
554 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
555 tr->name, tr->major, ret);
556 mutex_unlock(&mtd_table_mutex);
563 tr->blkshift = ffs(tr->blksize) - 1;
565 INIT_LIST_HEAD(&tr->devs);
566 list_add(&tr->list, &blktrans_majors);
568 mtd_for_each_device(mtd)
569 if (mtd->type != MTD_ABSENT)
570 tr->add_mtd(tr, mtd);
572 mutex_unlock(&mtd_table_mutex);
576 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
578 struct mtd_blktrans_dev *dev, *next;
580 mutex_lock(&mtd_table_mutex);
582 /* Remove it from the list of active majors */
585 list_for_each_entry_safe(dev, next, &tr->devs, list)
588 unregister_blkdev(tr->major, tr->name);
589 mutex_unlock(&mtd_table_mutex);
591 BUG_ON(!list_empty(&tr->devs));
595 static void __exit mtd_blktrans_exit(void)
597 /* No race here -- if someone's currently in register_mtd_blktrans
598 we're screwed anyway. */
599 if (blktrans_notifier.list.next)
600 unregister_mtd_user(&blktrans_notifier);
603 module_exit(mtd_blktrans_exit);
605 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
606 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
607 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
608 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
610 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
611 MODULE_LICENSE("GPL");
612 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");