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 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 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 (!blk_fs_request(req
))
93 if (blk_rq_pos(req
) + blk_rq_cur_sectors(req
) >
94 get_capacity(req
->rq_disk
))
97 if (blk_discard_rq(req
))
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 static int mtd_blktrans_thread(void *arg
)
124 struct mtd_blktrans_dev
*dev
= arg
;
125 struct request_queue
*rq
= dev
->rq
;
126 struct request
*req
= NULL
;
128 spin_lock_irq(rq
->queue_lock
);
130 while (!kthread_should_stop()) {
133 if (!req
&& !(req
= blk_fetch_request(rq
))) {
134 set_current_state(TASK_INTERRUPTIBLE
);
135 spin_unlock_irq(rq
->queue_lock
);
137 spin_lock_irq(rq
->queue_lock
);
141 spin_unlock_irq(rq
->queue_lock
);
143 mutex_lock(&dev
->lock
);
144 res
= do_blktrans_request(dev
->tr
, dev
, req
);
145 mutex_unlock(&dev
->lock
);
147 spin_lock_irq(rq
->queue_lock
);
149 if (!__blk_end_request_cur(req
, res
))
154 __blk_end_request_all(req
, -EIO
);
156 spin_unlock_irq(rq
->queue_lock
);
161 static void mtd_blktrans_request(struct request_queue
*rq
)
163 struct mtd_blktrans_dev
*dev
;
164 struct request
*req
= NULL
;
169 while ((req
= blk_fetch_request(rq
)) != NULL
)
170 __blk_end_request_all(req
, -ENODEV
);
172 wake_up_process(dev
->thread
);
175 static int blktrans_open(struct block_device
*bdev
, fmode_t mode
)
177 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
183 mutex_lock(&dev
->lock
);
190 ret
= !dev
->open
++ && dev
->tr
->open
? dev
->tr
->open(dev
) : 0;
192 /* Take another reference on the device so it won't go away till
197 mutex_unlock(&dev
->lock
);
198 blktrans_dev_put(dev
);
202 static int blktrans_release(struct gendisk
*disk
, fmode_t mode
)
204 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(disk
);
210 mutex_lock(&dev
->lock
);
212 /* Release one reference, we sure its not the last one here*/
213 kref_put(&dev
->ref
, blktrans_dev_release
);
218 ret
= !--dev
->open
&& dev
->tr
->release
? dev
->tr
->release(dev
) : 0;
220 mutex_unlock(&dev
->lock
);
221 blktrans_dev_put(dev
);
225 static int blktrans_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
227 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
233 mutex_lock(&dev
->lock
);
238 ret
= dev
->tr
->getgeo
? dev
->tr
->getgeo(dev
, geo
) : 0;
240 mutex_unlock(&dev
->lock
);
241 blktrans_dev_put(dev
);
245 static int blktrans_ioctl(struct block_device
*bdev
, fmode_t mode
,
246 unsigned int cmd
, unsigned long arg
)
248 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
254 mutex_lock(&dev
->lock
);
261 ret
= dev
->tr
->flush
? dev
->tr
->flush(dev
) : 0;
267 mutex_unlock(&dev
->lock
);
268 blktrans_dev_put(dev
);
272 static const struct block_device_operations mtd_blktrans_ops
= {
273 .owner
= THIS_MODULE
,
274 .open
= blktrans_open
,
275 .release
= blktrans_release
,
276 .locked_ioctl
= blktrans_ioctl
,
277 .getgeo
= blktrans_getgeo
,
280 int add_mtd_blktrans_dev(struct mtd_blktrans_dev
*new)
282 struct mtd_blktrans_ops
*tr
= new->tr
;
283 struct mtd_blktrans_dev
*d
;
284 int last_devnum
= -1;
288 if (mutex_trylock(&mtd_table_mutex
)) {
289 mutex_unlock(&mtd_table_mutex
);
293 mutex_lock(&blktrans_ref_mutex
);
294 list_for_each_entry(d
, &tr
->devs
, list
) {
295 if (new->devnum
== -1) {
296 /* Use first free number */
297 if (d
->devnum
!= last_devnum
+1) {
298 /* Found a free devnum. Plug it in here */
299 new->devnum
= last_devnum
+1;
300 list_add_tail(&new->list
, &d
->list
);
303 } else if (d
->devnum
== new->devnum
) {
304 /* Required number taken */
305 mutex_unlock(&blktrans_ref_mutex
);
307 } else if (d
->devnum
> new->devnum
) {
308 /* Required number was free */
309 list_add_tail(&new->list
, &d
->list
);
312 last_devnum
= d
->devnum
;
316 if (new->devnum
== -1)
317 new->devnum
= last_devnum
+1;
319 /* Check that the device and any partitions will get valid
320 * minor numbers and that the disk naming code below can cope
321 * with this number. */
322 if (new->devnum
> (MINORMASK
>> tr
->part_bits
) ||
323 (tr
->part_bits
&& new->devnum
>= 27 * 26)) {
324 mutex_unlock(&blktrans_ref_mutex
);
328 list_add_tail(&new->list
, &tr
->devs
);
330 mutex_unlock(&blktrans_ref_mutex
);
332 mutex_init(&new->lock
);
333 kref_init(&new->ref
);
339 gd
= alloc_disk(1 << tr
->part_bits
);
345 gd
->private_data
= new;
346 gd
->major
= tr
->major
;
347 gd
->first_minor
= (new->devnum
) << tr
->part_bits
;
348 gd
->fops
= &mtd_blktrans_ops
;
351 if (new->devnum
< 26)
352 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
353 "%s%c", tr
->name
, 'a' + new->devnum
);
355 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
357 'a' - 1 + new->devnum
/ 26,
358 'a' + new->devnum
% 26);
360 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
361 "%s%d", tr
->name
, new->devnum
);
363 set_capacity(gd
, (new->size
* tr
->blksize
) >> 9);
365 /* Create the request queue */
366 spin_lock_init(&new->queue_lock
);
367 new->rq
= blk_init_queue(mtd_blktrans_request
, &new->queue_lock
);
372 new->rq
->queuedata
= new;
373 blk_queue_logical_block_size(new->rq
, tr
->blksize
);
376 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
,
381 __get_mtd_device(new->mtd
);
382 __module_get(tr
->owner
);
384 /* Create processing thread */
385 /* TODO: workqueue ? */
386 new->thread
= kthread_run(mtd_blktrans_thread
, new,
387 "%s%d", tr
->name
, new->mtd
->index
);
388 if (IS_ERR(new->thread
)) {
389 ret
= PTR_ERR(new->thread
);
392 gd
->driverfs_dev
= &new->mtd
->dev
;
399 if (new->disk_attributes
) {
400 ret
= sysfs_create_group(&disk_to_dev(gd
)->kobj
,
401 new->disk_attributes
);
406 module_put(tr
->owner
);
407 __put_mtd_device(new->mtd
);
408 blk_cleanup_queue(new->rq
);
412 list_del(&new->list
);
418 int del_mtd_blktrans_dev(struct mtd_blktrans_dev
*old
)
422 if (mutex_trylock(&mtd_table_mutex
)) {
423 mutex_unlock(&mtd_table_mutex
);
427 if (old
->disk_attributes
)
428 sysfs_remove_group(&disk_to_dev(old
->disk
)->kobj
,
429 old
->disk_attributes
);
431 /* Stop new requests to arrive */
432 del_gendisk(old
->disk
);
435 /* Stop the thread */
436 kthread_stop(old
->thread
);
438 /* Kill current requests */
439 spin_lock_irqsave(&old
->queue_lock
, flags
);
440 old
->rq
->queuedata
= NULL
;
441 blk_start_queue(old
->rq
);
442 spin_unlock_irqrestore(&old
->queue_lock
, flags
);
444 /* Ask trans driver for release to the mtd device */
445 mutex_lock(&old
->lock
);
446 if (old
->open
&& old
->tr
->release
) {
447 old
->tr
->release(old
);
451 __put_mtd_device(old
->mtd
);
452 module_put(old
->tr
->owner
);
454 /* At that point, we don't touch the mtd anymore */
457 mutex_unlock(&old
->lock
);
458 blktrans_dev_put(old
);
462 static void blktrans_notify_remove(struct mtd_info
*mtd
)
464 struct mtd_blktrans_ops
*tr
;
465 struct mtd_blktrans_dev
*dev
, *next
;
467 list_for_each_entry(tr
, &blktrans_majors
, list
)
468 list_for_each_entry_safe(dev
, next
, &tr
->devs
, list
)
473 static void blktrans_notify_add(struct mtd_info
*mtd
)
475 struct mtd_blktrans_ops
*tr
;
477 if (mtd
->type
== MTD_ABSENT
)
480 list_for_each_entry(tr
, &blktrans_majors
, list
)
481 tr
->add_mtd(tr
, mtd
);
484 static struct mtd_notifier blktrans_notifier
= {
485 .add
= blktrans_notify_add
,
486 .remove
= blktrans_notify_remove
,
489 int register_mtd_blktrans(struct mtd_blktrans_ops
*tr
)
491 struct mtd_info
*mtd
;
494 /* Register the notifier if/when the first device type is
495 registered, to prevent the link/init ordering from fucking
497 if (!blktrans_notifier
.list
.next
)
498 register_mtd_user(&blktrans_notifier
);
501 mutex_lock(&mtd_table_mutex
);
503 ret
= register_blkdev(tr
->major
, tr
->name
);
505 printk(KERN_WARNING
"Unable to register %s block device on major %d: %d\n",
506 tr
->name
, tr
->major
, ret
);
507 mutex_unlock(&mtd_table_mutex
);
511 tr
->blkshift
= ffs(tr
->blksize
) - 1;
513 INIT_LIST_HEAD(&tr
->devs
);
514 list_add(&tr
->list
, &blktrans_majors
);
516 mtd_for_each_device(mtd
)
517 if (mtd
->type
!= MTD_ABSENT
)
518 tr
->add_mtd(tr
, mtd
);
520 mutex_unlock(&mtd_table_mutex
);
524 int deregister_mtd_blktrans(struct mtd_blktrans_ops
*tr
)
526 struct mtd_blktrans_dev
*dev
, *next
;
528 mutex_lock(&mtd_table_mutex
);
530 /* Remove it from the list of active majors */
533 list_for_each_entry_safe(dev
, next
, &tr
->devs
, list
)
536 unregister_blkdev(tr
->major
, tr
->name
);
537 mutex_unlock(&mtd_table_mutex
);
539 BUG_ON(!list_empty(&tr
->devs
));
543 static void __exit
mtd_blktrans_exit(void)
545 /* No race here -- if someone's currently in register_mtd_blktrans
546 we're screwed anyway. */
547 if (blktrans_notifier
.list
.next
)
548 unregister_mtd_user(&blktrans_notifier
);
551 module_exit(mtd_blktrans_exit
);
553 EXPORT_SYMBOL_GPL(register_mtd_blktrans
);
554 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans
);
555 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev
);
556 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev
);
558 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
559 MODULE_LICENSE("GPL");
560 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");