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/smp_lock.h>
33 #include <linux/hdreg.h>
34 #include <linux/init.h>
35 #include <linux/mutex.h>
36 #include <linux/kthread.h>
37 #include <asm/uaccess.h>
41 static LIST_HEAD(blktrans_majors
);
42 static DEFINE_MUTEX(blktrans_ref_mutex
);
44 void blktrans_dev_release(struct kref
*kref
)
46 struct mtd_blktrans_dev
*dev
=
47 container_of(kref
, struct mtd_blktrans_dev
, ref
);
49 dev
->disk
->private_data
= NULL
;
50 blk_cleanup_queue(dev
->rq
);
56 static struct mtd_blktrans_dev
*blktrans_dev_get(struct gendisk
*disk
)
58 struct mtd_blktrans_dev
*dev
;
60 mutex_lock(&blktrans_ref_mutex
);
61 dev
= disk
->private_data
;
67 mutex_unlock(&blktrans_ref_mutex
);
71 void blktrans_dev_put(struct mtd_blktrans_dev
*dev
)
73 mutex_lock(&blktrans_ref_mutex
);
74 kref_put(&dev
->ref
, blktrans_dev_release
);
75 mutex_unlock(&blktrans_ref_mutex
);
79 static int do_blktrans_request(struct mtd_blktrans_ops
*tr
,
80 struct mtd_blktrans_dev
*dev
,
83 unsigned long block
, nsect
;
86 block
= blk_rq_pos(req
) << 9 >> tr
->blkshift
;
87 nsect
= blk_rq_cur_bytes(req
) >> tr
->blkshift
;
91 if (req
->cmd_type
!= REQ_TYPE_FS
)
94 if (blk_rq_pos(req
) + blk_rq_cur_sectors(req
) >
95 get_capacity(req
->rq_disk
))
98 if (req
->cmd_flags
& REQ_DISCARD
)
99 return tr
->discard(dev
, block
, nsect
);
101 switch(rq_data_dir(req
)) {
103 for (; nsect
> 0; nsect
--, block
++, buf
+= tr
->blksize
)
104 if (tr
->readsect(dev
, block
, buf
))
106 rq_flush_dcache_pages(req
);
112 rq_flush_dcache_pages(req
);
113 for (; nsect
> 0; nsect
--, block
++, buf
+= tr
->blksize
)
114 if (tr
->writesect(dev
, block
, buf
))
118 printk(KERN_NOTICE
"Unknown request %u\n", rq_data_dir(req
));
123 static int mtd_blktrans_thread(void *arg
)
125 struct mtd_blktrans_dev
*dev
= arg
;
126 struct request_queue
*rq
= dev
->rq
;
127 struct request
*req
= NULL
;
129 spin_lock_irq(rq
->queue_lock
);
131 while (!kthread_should_stop()) {
134 if (!req
&& !(req
= blk_fetch_request(rq
))) {
135 set_current_state(TASK_INTERRUPTIBLE
);
136 spin_unlock_irq(rq
->queue_lock
);
138 spin_lock_irq(rq
->queue_lock
);
142 spin_unlock_irq(rq
->queue_lock
);
144 mutex_lock(&dev
->lock
);
145 res
= do_blktrans_request(dev
->tr
, dev
, req
);
146 mutex_unlock(&dev
->lock
);
148 spin_lock_irq(rq
->queue_lock
);
150 if (!__blk_end_request_cur(req
, res
))
155 __blk_end_request_all(req
, -EIO
);
157 spin_unlock_irq(rq
->queue_lock
);
162 static void mtd_blktrans_request(struct request_queue
*rq
)
164 struct mtd_blktrans_dev
*dev
;
165 struct request
*req
= NULL
;
170 while ((req
= blk_fetch_request(rq
)) != NULL
)
171 __blk_end_request_all(req
, -ENODEV
);
173 wake_up_process(dev
->thread
);
176 static int blktrans_open(struct block_device
*bdev
, fmode_t mode
)
178 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
182 return -ERESTARTSYS
; /* FIXME: busy loop! -arnd*/
185 mutex_lock(&dev
->lock
);
192 ret
= !dev
->open
++ && dev
->tr
->open
? dev
->tr
->open(dev
) : 0;
194 /* Take another reference on the device so it won't go away till
199 mutex_unlock(&dev
->lock
);
200 blktrans_dev_put(dev
);
205 static int blktrans_release(struct gendisk
*disk
, fmode_t mode
)
207 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(disk
);
214 mutex_lock(&dev
->lock
);
216 /* Release one reference, we sure its not the last one here*/
217 kref_put(&dev
->ref
, blktrans_dev_release
);
222 ret
= !--dev
->open
&& dev
->tr
->release
? dev
->tr
->release(dev
) : 0;
224 mutex_unlock(&dev
->lock
);
225 blktrans_dev_put(dev
);
230 static int blktrans_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
232 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
238 mutex_lock(&dev
->lock
);
243 ret
= dev
->tr
->getgeo
? dev
->tr
->getgeo(dev
, geo
) : 0;
245 mutex_unlock(&dev
->lock
);
246 blktrans_dev_put(dev
);
250 static int blktrans_ioctl(struct block_device
*bdev
, fmode_t mode
,
251 unsigned int cmd
, unsigned long arg
)
253 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
260 mutex_lock(&dev
->lock
);
267 ret
= dev
->tr
->flush
? dev
->tr
->flush(dev
) : 0;
273 mutex_unlock(&dev
->lock
);
275 blktrans_dev_put(dev
);
279 static const struct block_device_operations mtd_blktrans_ops
= {
280 .owner
= THIS_MODULE
,
281 .open
= blktrans_open
,
282 .release
= blktrans_release
,
283 .ioctl
= blktrans_ioctl
,
284 .getgeo
= blktrans_getgeo
,
287 int add_mtd_blktrans_dev(struct mtd_blktrans_dev
*new)
289 struct mtd_blktrans_ops
*tr
= new->tr
;
290 struct mtd_blktrans_dev
*d
;
291 int last_devnum
= -1;
295 if (mutex_trylock(&mtd_table_mutex
)) {
296 mutex_unlock(&mtd_table_mutex
);
300 mutex_lock(&blktrans_ref_mutex
);
301 list_for_each_entry(d
, &tr
->devs
, list
) {
302 if (new->devnum
== -1) {
303 /* Use first free number */
304 if (d
->devnum
!= last_devnum
+1) {
305 /* Found a free devnum. Plug it in here */
306 new->devnum
= last_devnum
+1;
307 list_add_tail(&new->list
, &d
->list
);
310 } else if (d
->devnum
== new->devnum
) {
311 /* Required number taken */
312 mutex_unlock(&blktrans_ref_mutex
);
314 } else if (d
->devnum
> new->devnum
) {
315 /* Required number was free */
316 list_add_tail(&new->list
, &d
->list
);
319 last_devnum
= d
->devnum
;
323 if (new->devnum
== -1)
324 new->devnum
= last_devnum
+1;
326 /* Check that the device and any partitions will get valid
327 * minor numbers and that the disk naming code below can cope
328 * with this number. */
329 if (new->devnum
> (MINORMASK
>> tr
->part_bits
) ||
330 (tr
->part_bits
&& new->devnum
>= 27 * 26)) {
331 mutex_unlock(&blktrans_ref_mutex
);
335 list_add_tail(&new->list
, &tr
->devs
);
337 mutex_unlock(&blktrans_ref_mutex
);
339 mutex_init(&new->lock
);
340 kref_init(&new->ref
);
346 gd
= alloc_disk(1 << tr
->part_bits
);
352 gd
->private_data
= new;
353 gd
->major
= tr
->major
;
354 gd
->first_minor
= (new->devnum
) << tr
->part_bits
;
355 gd
->fops
= &mtd_blktrans_ops
;
358 if (new->devnum
< 26)
359 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
360 "%s%c", tr
->name
, 'a' + new->devnum
);
362 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
364 'a' - 1 + new->devnum
/ 26,
365 'a' + new->devnum
% 26);
367 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
368 "%s%d", tr
->name
, new->devnum
);
370 set_capacity(gd
, (new->size
* tr
->blksize
) >> 9);
372 /* Create the request queue */
373 spin_lock_init(&new->queue_lock
);
374 new->rq
= blk_init_queue(mtd_blktrans_request
, &new->queue_lock
);
379 new->rq
->queuedata
= new;
380 blk_queue_logical_block_size(new->rq
, tr
->blksize
);
383 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
,
388 __get_mtd_device(new->mtd
);
389 __module_get(tr
->owner
);
391 /* Create processing thread */
392 /* TODO: workqueue ? */
393 new->thread
= kthread_run(mtd_blktrans_thread
, new,
394 "%s%d", tr
->name
, new->mtd
->index
);
395 if (IS_ERR(new->thread
)) {
396 ret
= PTR_ERR(new->thread
);
399 gd
->driverfs_dev
= &new->mtd
->dev
;
406 if (new->disk_attributes
) {
407 ret
= sysfs_create_group(&disk_to_dev(gd
)->kobj
,
408 new->disk_attributes
);
413 module_put(tr
->owner
);
414 __put_mtd_device(new->mtd
);
415 blk_cleanup_queue(new->rq
);
419 list_del(&new->list
);
425 int del_mtd_blktrans_dev(struct mtd_blktrans_dev
*old
)
429 if (mutex_trylock(&mtd_table_mutex
)) {
430 mutex_unlock(&mtd_table_mutex
);
434 if (old
->disk_attributes
)
435 sysfs_remove_group(&disk_to_dev(old
->disk
)->kobj
,
436 old
->disk_attributes
);
438 /* Stop new requests to arrive */
439 del_gendisk(old
->disk
);
442 /* Stop the thread */
443 kthread_stop(old
->thread
);
445 /* Kill current requests */
446 spin_lock_irqsave(&old
->queue_lock
, flags
);
447 old
->rq
->queuedata
= NULL
;
448 blk_start_queue(old
->rq
);
449 spin_unlock_irqrestore(&old
->queue_lock
, flags
);
451 /* Ask trans driver for release to the mtd device */
452 mutex_lock(&old
->lock
);
453 if (old
->open
&& old
->tr
->release
) {
454 old
->tr
->release(old
);
458 __put_mtd_device(old
->mtd
);
459 module_put(old
->tr
->owner
);
461 /* At that point, we don't touch the mtd anymore */
464 mutex_unlock(&old
->lock
);
465 blktrans_dev_put(old
);
469 static void blktrans_notify_remove(struct mtd_info
*mtd
)
471 struct mtd_blktrans_ops
*tr
;
472 struct mtd_blktrans_dev
*dev
, *next
;
474 list_for_each_entry(tr
, &blktrans_majors
, list
)
475 list_for_each_entry_safe(dev
, next
, &tr
->devs
, list
)
480 static void blktrans_notify_add(struct mtd_info
*mtd
)
482 struct mtd_blktrans_ops
*tr
;
484 if (mtd
->type
== MTD_ABSENT
)
487 list_for_each_entry(tr
, &blktrans_majors
, list
)
488 tr
->add_mtd(tr
, mtd
);
491 static struct mtd_notifier blktrans_notifier
= {
492 .add
= blktrans_notify_add
,
493 .remove
= blktrans_notify_remove
,
496 int register_mtd_blktrans(struct mtd_blktrans_ops
*tr
)
498 struct mtd_info
*mtd
;
501 /* Register the notifier if/when the first device type is
502 registered, to prevent the link/init ordering from fucking
504 if (!blktrans_notifier
.list
.next
)
505 register_mtd_user(&blktrans_notifier
);
508 mutex_lock(&mtd_table_mutex
);
510 ret
= register_blkdev(tr
->major
, tr
->name
);
512 printk(KERN_WARNING
"Unable to register %s block device on major %d: %d\n",
513 tr
->name
, tr
->major
, ret
);
514 mutex_unlock(&mtd_table_mutex
);
518 tr
->blkshift
= ffs(tr
->blksize
) - 1;
520 INIT_LIST_HEAD(&tr
->devs
);
521 list_add(&tr
->list
, &blktrans_majors
);
523 mtd_for_each_device(mtd
)
524 if (mtd
->type
!= MTD_ABSENT
)
525 tr
->add_mtd(tr
, mtd
);
527 mutex_unlock(&mtd_table_mutex
);
531 int deregister_mtd_blktrans(struct mtd_blktrans_ops
*tr
)
533 struct mtd_blktrans_dev
*dev
, *next
;
535 mutex_lock(&mtd_table_mutex
);
537 /* Remove it from the list of active majors */
540 list_for_each_entry_safe(dev
, next
, &tr
->devs
, list
)
543 unregister_blkdev(tr
->major
, tr
->name
);
544 mutex_unlock(&mtd_table_mutex
);
546 BUG_ON(!list_empty(&tr
->devs
));
550 static void __exit
mtd_blktrans_exit(void)
552 /* No race here -- if someone's currently in register_mtd_blktrans
553 we're screwed anyway. */
554 if (blktrans_notifier
.list
.next
)
555 unregister_mtd_user(&blktrans_notifier
);
558 module_exit(mtd_blktrans_exit
);
560 EXPORT_SYMBOL_GPL(register_mtd_blktrans
);
561 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans
);
562 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev
);
563 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev
);
565 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
566 MODULE_LICENSE("GPL");
567 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");