1 /*
2 * Interface to Linux block layer for MTD 'translation layers'.
3 *
4 * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
5 *
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.
10 *
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.
15 *
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
19 *
20 */
21
22 #include <linux/kernel.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/list.h>
26 #include <linux/fs.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>
37
38 #include "mtdcore.h"
39
40 static LIST_HEAD(blktrans_majors);
41 static DEFINE_MUTEX(blktrans_ref_mutex);
42
blktrans_dev_release(struct kref * kref)43 static void blktrans_dev_release(struct kref *kref)
44 {
45 struct mtd_blktrans_dev *dev =
46 container_of(kref, struct mtd_blktrans_dev, ref);
47
48 dev->disk->private_data = NULL;
49 blk_cleanup_queue(dev->rq);
50 put_disk(dev->disk);
51 list_del(&dev->list);
52 kfree(dev);
53 }
54
blktrans_dev_get(struct gendisk * disk)55 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
56 {
57 struct mtd_blktrans_dev *dev;
58
59 mutex_lock(&blktrans_ref_mutex);
60 dev = disk->private_data;
61
62 if (!dev)
63 goto unlock;
64 kref_get(&dev->ref);
65 unlock:
66 mutex_unlock(&blktrans_ref_mutex);
67 return dev;
68 }
69
blktrans_dev_put(struct mtd_blktrans_dev * dev)70 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
71 {
72 mutex_lock(&blktrans_ref_mutex);
73 kref_put(&dev->ref, blktrans_dev_release);
74 mutex_unlock(&blktrans_ref_mutex);
75 }
76
77
do_blktrans_request(struct mtd_blktrans_ops * tr,struct mtd_blktrans_dev * dev,struct request * req)78 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
79 struct mtd_blktrans_dev *dev,
80 struct request *req)
81 {
82 unsigned long block, nsect;
83 char *buf;
84
85 block = blk_rq_pos(req) << 9 >> tr->blkshift;
86 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
87
88 buf = req->buffer;
89
90 if (req->cmd_type != REQ_TYPE_FS)
91 return -EIO;
92
93 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
94 get_capacity(req->rq_disk))
95 return -EIO;
96
97 if (req->cmd_flags & REQ_DISCARD)
98 return tr->discard(dev, block, nsect);
99
100 switch(rq_data_dir(req)) {
101 case READ:
102 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
103 if (tr->readsect(dev, block, buf))
104 return -EIO;
105 rq_flush_dcache_pages(req);
106 return 0;
107 case WRITE:
108 if (!tr->writesect)
109 return -EIO;
110
111 rq_flush_dcache_pages(req);
112 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
113 if (tr->writesect(dev, block, buf))
114 return -EIO;
115 return 0;
116 default:
117 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
118 return -EIO;
119 }
120 }
121
mtd_blktrans_cease_background(struct mtd_blktrans_dev * dev)122 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
123 {
124 if (kthread_should_stop())
125 return 1;
126
127 return dev->bg_stop;
128 }
129 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
130
mtd_blktrans_thread(void * arg)131 static int mtd_blktrans_thread(void *arg)
132 {
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;
138
139 spin_lock_irq(rq->queue_lock);
140
141 while (!kthread_should_stop()) {
142 int res;
143
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);
149 tr->background(dev);
150 mutex_unlock(&dev->lock);
151 spin_lock_irq(rq->queue_lock);
152 /*
153 * Do background processing just once per idle
154 * period.
155 */
156 background_done = !dev->bg_stop;
157 continue;
158 }
159 set_current_state(TASK_INTERRUPTIBLE);
160
161 if (kthread_should_stop())
162 set_current_state(TASK_RUNNING);
163
164 spin_unlock_irq(rq->queue_lock);
165 schedule();
166 spin_lock_irq(rq->queue_lock);
167 continue;
168 }
169
170 spin_unlock_irq(rq->queue_lock);
171
172 mutex_lock(&dev->lock);
173 res = do_blktrans_request(dev->tr, dev, req);
174 mutex_unlock(&dev->lock);
175
176 spin_lock_irq(rq->queue_lock);
177
178 if (!__blk_end_request_cur(req, res))
179 req = NULL;
180
181 background_done = 0;
182 }
183
184 if (req)
185 __blk_end_request_all(req, -EIO);
186
187 spin_unlock_irq(rq->queue_lock);
188
189 return 0;
190 }
191
mtd_blktrans_request(struct request_queue * rq)192 static void mtd_blktrans_request(struct request_queue *rq)
193 {
194 struct mtd_blktrans_dev *dev;
195 struct request *req = NULL;
196
197 dev = rq->queuedata;
198
199 if (!dev)
200 while ((req = blk_fetch_request(rq)) != NULL)
201 __blk_end_request_all(req, -ENODEV);
202 else {
203 dev->bg_stop = true;
204 wake_up_process(dev->thread);
205 }
206 }
207
blktrans_open(struct block_device * bdev,fmode_t mode)208 static int blktrans_open(struct block_device *bdev, fmode_t mode)
209 {
210 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
211 int ret = 0;
212
213 if (!dev)
214 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
215
216 mutex_lock(&dev->lock);
217
218 if (dev->open++)
219 goto unlock;
220
221 kref_get(&dev->ref);
222 __module_get(dev->tr->owner);
223
224 if (dev->mtd) {
225 ret = dev->tr->open ? dev->tr->open(dev) : 0;
226 __get_mtd_device(dev->mtd);
227 }
228
229 unlock:
230 mutex_unlock(&dev->lock);
231 blktrans_dev_put(dev);
232 return ret;
233 }
234
blktrans_release(struct gendisk * disk,fmode_t mode)235 static int blktrans_release(struct gendisk *disk, fmode_t mode)
236 {
237 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
238 int ret = 0;
239
240 if (!dev)
241 return ret;
242
243 mutex_lock(&dev->lock);
244
245 if (--dev->open)
246 goto unlock;
247
248 kref_put(&dev->ref, blktrans_dev_release);
249 module_put(dev->tr->owner);
250
251 if (dev->mtd) {
252 ret = dev->tr->release ? dev->tr->release(dev) : 0;
253 __put_mtd_device(dev->mtd);
254 }
255 unlock:
256 mutex_unlock(&dev->lock);
257 blktrans_dev_put(dev);
258 return ret;
259 }
260
blktrans_getgeo(struct block_device * bdev,struct hd_geometry * geo)261 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
262 {
263 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
264 int ret = -ENXIO;
265
266 if (!dev)
267 return ret;
268
269 mutex_lock(&dev->lock);
270
271 if (!dev->mtd)
272 goto unlock;
273
274 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
275 unlock:
276 mutex_unlock(&dev->lock);
277 blktrans_dev_put(dev);
278 return ret;
279 }
280
blktrans_ioctl(struct block_device * bdev,fmode_t mode,unsigned int cmd,unsigned long arg)281 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
282 unsigned int cmd, unsigned long arg)
283 {
284 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
285 int ret = -ENXIO;
286
287 if (!dev)
288 return ret;
289
290 mutex_lock(&dev->lock);
291
292 if (!dev->mtd)
293 goto unlock;
294
295 switch (cmd) {
296 case BLKFLSBUF:
297 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
298 break;
299 default:
300 ret = -ENOTTY;
301 }
302 unlock:
303 mutex_unlock(&dev->lock);
304 blktrans_dev_put(dev);
305 return ret;
306 }
307
308 static const struct block_device_operations mtd_blktrans_ops = {
309 .owner = THIS_MODULE,
310 .open = blktrans_open,
311 .release = blktrans_release,
312 .ioctl = blktrans_ioctl,
313 .getgeo = blktrans_getgeo,
314 };
315
add_mtd_blktrans_dev(struct mtd_blktrans_dev * new)316 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
317 {
318 struct mtd_blktrans_ops *tr = new->tr;
319 struct mtd_blktrans_dev *d;
320 int last_devnum = -1;
321 struct gendisk *gd;
322 int ret;
323
324 if (mutex_trylock(&mtd_table_mutex)) {
325 mutex_unlock(&mtd_table_mutex);
326 BUG();
327 }
328
329 mutex_lock(&blktrans_ref_mutex);
330 list_for_each_entry(d, &tr->devs, list) {
331 if (new->devnum == -1) {
332 /* Use first free number */
333 if (d->devnum != last_devnum+1) {
334 /* Found a free devnum. Plug it in here */
335 new->devnum = last_devnum+1;
336 list_add_tail(&new->list, &d->list);
337 goto added;
338 }
339 } else if (d->devnum == new->devnum) {
340 /* Required number taken */
341 mutex_unlock(&blktrans_ref_mutex);
342 return -EBUSY;
343 } else if (d->devnum > new->devnum) {
344 /* Required number was free */
345 list_add_tail(&new->list, &d->list);
346 goto added;
347 }
348 last_devnum = d->devnum;
349 }
350
351 ret = -EBUSY;
352 if (new->devnum == -1)
353 new->devnum = last_devnum+1;
354
355 /* Check that the device and any partitions will get valid
356 * minor numbers and that the disk naming code below can cope
357 * with this number. */
358 if (new->devnum > (MINORMASK >> tr->part_bits) ||
359 (tr->part_bits && new->devnum >= 27 * 26)) {
360 mutex_unlock(&blktrans_ref_mutex);
361 goto error1;
362 }
363
364 list_add_tail(&new->list, &tr->devs);
365 added:
366 mutex_unlock(&blktrans_ref_mutex);
367
368 mutex_init(&new->lock);
369 kref_init(&new->ref);
370 if (!tr->writesect)
371 new->readonly = 1;
372
373 /* Create gendisk */
374 ret = -ENOMEM;
375 gd = alloc_disk(1 << tr->part_bits);
376
377 if (!gd)
378 goto error2;
379
380 new->disk = gd;
381 gd->private_data = new;
382 gd->major = tr->major;
383 gd->first_minor = (new->devnum) << tr->part_bits;
384 gd->fops = &mtd_blktrans_ops;
385
386 if (tr->part_bits)
387 if (new->devnum < 26)
388 snprintf(gd->disk_name, sizeof(gd->disk_name),
389 "%s%c", tr->name, 'a' + new->devnum);
390 else
391 snprintf(gd->disk_name, sizeof(gd->disk_name),
392 "%s%c%c", tr->name,
393 'a' - 1 + new->devnum / 26,
394 'a' + new->devnum % 26);
395 else
396 snprintf(gd->disk_name, sizeof(gd->disk_name),
397 "%s%d", tr->name, new->devnum);
398
399 set_capacity(gd, (new->size * tr->blksize) >> 9);
400
401 /* Create the request queue */
402 spin_lock_init(&new->queue_lock);
403 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
404
405 if (!new->rq)
406 goto error3;
407
408 new->rq->queuedata = new;
409 blk_queue_logical_block_size(new->rq, tr->blksize);
410
411 if (tr->discard) {
412 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
413 new->rq->limits.max_discard_sectors = UINT_MAX;
414 }
415
416 gd->queue = new->rq;
417
418 /* Create processing thread */
419 /* TODO: workqueue ? */
420 new->thread = kthread_run(mtd_blktrans_thread, new,
421 "%s%d", tr->name, new->mtd->index);
422 if (IS_ERR(new->thread)) {
423 ret = PTR_ERR(new->thread);
424 goto error4;
425 }
426 gd->driverfs_dev = &new->mtd->dev;
427
428 if (new->readonly)
429 set_disk_ro(gd, 1);
430
431 add_disk(gd);
432
433 if (new->disk_attributes) {
434 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
435 new->disk_attributes);
436 WARN_ON(ret);
437 }
438 return 0;
439 error4:
440 blk_cleanup_queue(new->rq);
441 error3:
442 put_disk(new->disk);
443 error2:
444 list_del(&new->list);
445 error1:
446 return ret;
447 }
448
del_mtd_blktrans_dev(struct mtd_blktrans_dev * old)449 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
450 {
451 unsigned long flags;
452
453 if (mutex_trylock(&mtd_table_mutex)) {
454 mutex_unlock(&mtd_table_mutex);
455 BUG();
456 }
457
458 if (old->disk_attributes)
459 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
460 old->disk_attributes);
461
462 /* Stop new requests to arrive */
463 del_gendisk(old->disk);
464
465
466 /* Stop the thread */
467 kthread_stop(old->thread);
468
469 /* Kill current requests */
470 spin_lock_irqsave(&old->queue_lock, flags);
471 old->rq->queuedata = NULL;
472 blk_start_queue(old->rq);
473 spin_unlock_irqrestore(&old->queue_lock, flags);
474
475 /* If the device is currently open, tell trans driver to close it,
476 then put mtd device, and don't touch it again */
477 mutex_lock(&old->lock);
478 if (old->open) {
479 if (old->tr->release)
480 old->tr->release(old);
481 __put_mtd_device(old->mtd);
482 }
483
484 old->mtd = NULL;
485
486 mutex_unlock(&old->lock);
487 blktrans_dev_put(old);
488 return 0;
489 }
490
blktrans_notify_remove(struct mtd_info * mtd)491 static void blktrans_notify_remove(struct mtd_info *mtd)
492 {
493 struct mtd_blktrans_ops *tr;
494 struct mtd_blktrans_dev *dev, *next;
495
496 list_for_each_entry(tr, &blktrans_majors, list)
497 list_for_each_entry_safe(dev, next, &tr->devs, list)
498 if (dev->mtd == mtd)
499 tr->remove_dev(dev);
500 }
501
blktrans_notify_add(struct mtd_info * mtd)502 static void blktrans_notify_add(struct mtd_info *mtd)
503 {
504 struct mtd_blktrans_ops *tr;
505
506 if (mtd->type == MTD_ABSENT)
507 return;
508
509 list_for_each_entry(tr, &blktrans_majors, list)
510 tr->add_mtd(tr, mtd);
511 }
512
513 static struct mtd_notifier blktrans_notifier = {
514 .add = blktrans_notify_add,
515 .remove = blktrans_notify_remove,
516 };
517
register_mtd_blktrans(struct mtd_blktrans_ops * tr)518 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
519 {
520 struct mtd_info *mtd;
521 int ret;
522
523 /* Register the notifier if/when the first device type is
524 registered, to prevent the link/init ordering from fucking
525 us over. */
526 if (!blktrans_notifier.list.next)
527 register_mtd_user(&blktrans_notifier);
528
529
530 mutex_lock(&mtd_table_mutex);
531
532 ret = register_blkdev(tr->major, tr->name);
533 if (ret < 0) {
534 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
535 tr->name, tr->major, ret);
536 mutex_unlock(&mtd_table_mutex);
537 return ret;
538 }
539
540 if (ret)
541 tr->major = ret;
542
543 tr->blkshift = ffs(tr->blksize) - 1;
544
545 INIT_LIST_HEAD(&tr->devs);
546 list_add(&tr->list, &blktrans_majors);
547
548 mtd_for_each_device(mtd)
549 if (mtd->type != MTD_ABSENT)
550 tr->add_mtd(tr, mtd);
551
552 mutex_unlock(&mtd_table_mutex);
553 return 0;
554 }
555
deregister_mtd_blktrans(struct mtd_blktrans_ops * tr)556 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
557 {
558 struct mtd_blktrans_dev *dev, *next;
559
560 mutex_lock(&mtd_table_mutex);
561
562 /* Remove it from the list of active majors */
563 list_del(&tr->list);
564
565 list_for_each_entry_safe(dev, next, &tr->devs, list)
566 tr->remove_dev(dev);
567
568 unregister_blkdev(tr->major, tr->name);
569 mutex_unlock(&mtd_table_mutex);
570
571 BUG_ON(!list_empty(&tr->devs));
572 return 0;
573 }
574
mtd_blktrans_exit(void)575 static void __exit mtd_blktrans_exit(void)
576 {
577 /* No race here -- if someone's currently in register_mtd_blktrans
578 we're screwed anyway. */
579 if (blktrans_notifier.list.next)
580 unregister_mtd_user(&blktrans_notifier);
581 }
582
583 module_exit(mtd_blktrans_exit);
584
585 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
586 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
587 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
588 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
589
590 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
591 MODULE_LICENSE("GPL");
592 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
593