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
);
137 if (kthread_should_stop())
138 set_current_state(TASK_RUNNING
);
140 spin_unlock_irq(rq
->queue_lock
);
142 spin_lock_irq(rq
->queue_lock
);
146 spin_unlock_irq(rq
->queue_lock
);
148 mutex_lock(&dev
->lock
);
149 res
= do_blktrans_request(dev
->tr
, dev
, req
);
150 mutex_unlock(&dev
->lock
);
152 spin_lock_irq(rq
->queue_lock
);
154 if (!__blk_end_request_cur(req
, res
))
159 __blk_end_request_all(req
, -EIO
);
161 spin_unlock_irq(rq
->queue_lock
);
166 static void mtd_blktrans_request(struct request_queue
*rq
)
168 struct mtd_blktrans_dev
*dev
;
169 struct request
*req
= NULL
;
174 while ((req
= blk_fetch_request(rq
)) != NULL
)
175 __blk_end_request_all(req
, -ENODEV
);
177 wake_up_process(dev
->thread
);
180 static int blktrans_open(struct block_device
*bdev
, fmode_t mode
)
182 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
186 return -ERESTARTSYS
; /* FIXME: busy loop! -arnd*/
188 mutex_lock(&dev
->lock
);
194 __module_get(dev
->tr
->owner
);
197 ret
= dev
->tr
->open
? dev
->tr
->open(dev
) : 0;
198 __get_mtd_device(dev
->mtd
);
202 mutex_unlock(&dev
->lock
);
203 blktrans_dev_put(dev
);
207 static int blktrans_release(struct gendisk
*disk
, fmode_t mode
)
209 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(disk
);
215 mutex_lock(&dev
->lock
);
220 kref_put(&dev
->ref
, blktrans_dev_release
);
221 module_put(dev
->tr
->owner
);
224 ret
= dev
->tr
->release
? dev
->tr
->release(dev
) : 0;
225 __put_mtd_device(dev
->mtd
);
228 mutex_unlock(&dev
->lock
);
229 blktrans_dev_put(dev
);
233 static int blktrans_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
235 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
241 mutex_lock(&dev
->lock
);
246 ret
= dev
->tr
->getgeo
? dev
->tr
->getgeo(dev
, geo
) : 0;
248 mutex_unlock(&dev
->lock
);
249 blktrans_dev_put(dev
);
253 static int blktrans_ioctl(struct block_device
*bdev
, fmode_t mode
,
254 unsigned int cmd
, unsigned long arg
)
256 struct mtd_blktrans_dev
*dev
= blktrans_dev_get(bdev
->bd_disk
);
262 mutex_lock(&dev
->lock
);
269 ret
= dev
->tr
->flush
? dev
->tr
->flush(dev
) : 0;
275 mutex_unlock(&dev
->lock
);
276 blktrans_dev_put(dev
);
280 static const struct block_device_operations mtd_blktrans_ops
= {
281 .owner
= THIS_MODULE
,
282 .open
= blktrans_open
,
283 .release
= blktrans_release
,
284 .ioctl
= blktrans_ioctl
,
285 .getgeo
= blktrans_getgeo
,
288 int add_mtd_blktrans_dev(struct mtd_blktrans_dev
*new)
290 struct mtd_blktrans_ops
*tr
= new->tr
;
291 struct mtd_blktrans_dev
*d
;
292 int last_devnum
= -1;
296 if (mutex_trylock(&mtd_table_mutex
)) {
297 mutex_unlock(&mtd_table_mutex
);
301 mutex_lock(&blktrans_ref_mutex
);
302 list_for_each_entry(d
, &tr
->devs
, list
) {
303 if (new->devnum
== -1) {
304 /* Use first free number */
305 if (d
->devnum
!= last_devnum
+1) {
306 /* Found a free devnum. Plug it in here */
307 new->devnum
= last_devnum
+1;
308 list_add_tail(&new->list
, &d
->list
);
311 } else if (d
->devnum
== new->devnum
) {
312 /* Required number taken */
313 mutex_unlock(&blktrans_ref_mutex
);
315 } else if (d
->devnum
> new->devnum
) {
316 /* Required number was free */
317 list_add_tail(&new->list
, &d
->list
);
320 last_devnum
= d
->devnum
;
324 if (new->devnum
== -1)
325 new->devnum
= last_devnum
+1;
327 /* Check that the device and any partitions will get valid
328 * minor numbers and that the disk naming code below can cope
329 * with this number. */
330 if (new->devnum
> (MINORMASK
>> tr
->part_bits
) ||
331 (tr
->part_bits
&& new->devnum
>= 27 * 26)) {
332 mutex_unlock(&blktrans_ref_mutex
);
336 list_add_tail(&new->list
, &tr
->devs
);
338 mutex_unlock(&blktrans_ref_mutex
);
340 mutex_init(&new->lock
);
341 kref_init(&new->ref
);
347 gd
= alloc_disk(1 << tr
->part_bits
);
353 gd
->private_data
= new;
354 gd
->major
= tr
->major
;
355 gd
->first_minor
= (new->devnum
) << tr
->part_bits
;
356 gd
->fops
= &mtd_blktrans_ops
;
359 if (new->devnum
< 26)
360 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
361 "%s%c", tr
->name
, 'a' + new->devnum
);
363 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
365 'a' - 1 + new->devnum
/ 26,
366 'a' + new->devnum
% 26);
368 snprintf(gd
->disk_name
, sizeof(gd
->disk_name
),
369 "%s%d", tr
->name
, new->devnum
);
371 set_capacity(gd
, (new->size
* tr
->blksize
) >> 9);
373 /* Create the request queue */
374 spin_lock_init(&new->queue_lock
);
375 new->rq
= blk_init_queue(mtd_blktrans_request
, &new->queue_lock
);
380 new->rq
->queuedata
= new;
381 blk_queue_logical_block_size(new->rq
, tr
->blksize
);
384 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
,
389 /* Create processing thread */
390 /* TODO: workqueue ? */
391 new->thread
= kthread_run(mtd_blktrans_thread
, new,
392 "%s%d", tr
->name
, new->mtd
->index
);
393 if (IS_ERR(new->thread
)) {
394 ret
= PTR_ERR(new->thread
);
397 gd
->driverfs_dev
= &new->mtd
->dev
;
404 if (new->disk_attributes
) {
405 ret
= sysfs_create_group(&disk_to_dev(gd
)->kobj
,
406 new->disk_attributes
);
411 blk_cleanup_queue(new->rq
);
415 list_del(&new->list
);
421 int del_mtd_blktrans_dev(struct mtd_blktrans_dev
*old
)
425 if (mutex_trylock(&mtd_table_mutex
)) {
426 mutex_unlock(&mtd_table_mutex
);
430 if (old
->disk_attributes
)
431 sysfs_remove_group(&disk_to_dev(old
->disk
)->kobj
,
432 old
->disk_attributes
);
434 /* Stop new requests to arrive */
435 del_gendisk(old
->disk
);
438 /* Stop the thread */
439 kthread_stop(old
->thread
);
441 /* Kill current requests */
442 spin_lock_irqsave(&old
->queue_lock
, flags
);
443 old
->rq
->queuedata
= NULL
;
444 blk_start_queue(old
->rq
);
445 spin_unlock_irqrestore(&old
->queue_lock
, flags
);
447 /* If the device is currently open, tell trans driver to close it,
448 then put mtd device, and don't touch it again */
449 mutex_lock(&old
->lock
);
451 if (old
->tr
->release
)
452 old
->tr
->release(old
);
453 __put_mtd_device(old
->mtd
);
458 mutex_unlock(&old
->lock
);
459 blktrans_dev_put(old
);
463 static void blktrans_notify_remove(struct mtd_info
*mtd
)
465 struct mtd_blktrans_ops
*tr
;
466 struct mtd_blktrans_dev
*dev
, *next
;
468 list_for_each_entry(tr
, &blktrans_majors
, list
)
469 list_for_each_entry_safe(dev
, next
, &tr
->devs
, list
)
474 static void blktrans_notify_add(struct mtd_info
*mtd
)
476 struct mtd_blktrans_ops
*tr
;
478 if (mtd
->type
== MTD_ABSENT
)
481 list_for_each_entry(tr
, &blktrans_majors
, list
)
482 tr
->add_mtd(tr
, mtd
);
485 static struct mtd_notifier blktrans_notifier
= {
486 .add
= blktrans_notify_add
,
487 .remove
= blktrans_notify_remove
,
490 int register_mtd_blktrans(struct mtd_blktrans_ops
*tr
)
492 struct mtd_info
*mtd
;
495 /* Register the notifier if/when the first device type is
496 registered, to prevent the link/init ordering from fucking
498 if (!blktrans_notifier
.list
.next
)
499 register_mtd_user(&blktrans_notifier
);
502 mutex_lock(&mtd_table_mutex
);
504 ret
= register_blkdev(tr
->major
, tr
->name
);
506 printk(KERN_WARNING
"Unable to register %s block device on major %d: %d\n",
507 tr
->name
, tr
->major
, ret
);
508 mutex_unlock(&mtd_table_mutex
);
515 tr
->blkshift
= ffs(tr
->blksize
) - 1;
517 INIT_LIST_HEAD(&tr
->devs
);
518 list_add(&tr
->list
, &blktrans_majors
);
520 mtd_for_each_device(mtd
)
521 if (mtd
->type
!= MTD_ABSENT
)
522 tr
->add_mtd(tr
, mtd
);
524 mutex_unlock(&mtd_table_mutex
);
528 int deregister_mtd_blktrans(struct mtd_blktrans_ops
*tr
)
530 struct mtd_blktrans_dev
*dev
, *next
;
532 mutex_lock(&mtd_table_mutex
);
534 /* Remove it from the list of active majors */
537 list_for_each_entry_safe(dev
, next
, &tr
->devs
, list
)
540 unregister_blkdev(tr
->major
, tr
->name
);
541 mutex_unlock(&mtd_table_mutex
);
543 BUG_ON(!list_empty(&tr
->devs
));
547 static void __exit
mtd_blktrans_exit(void)
549 /* No race here -- if someone's currently in register_mtd_blktrans
550 we're screwed anyway. */
551 if (blktrans_notifier
.list
.next
)
552 unregister_mtd_user(&blktrans_notifier
);
555 module_exit(mtd_blktrans_exit
);
557 EXPORT_SYMBOL_GPL(register_mtd_blktrans
);
558 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans
);
559 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev
);
560 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev
);
562 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
563 MODULE_LICENSE("GPL");
564 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");