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 goto unlock;
226
227 if (dev->tr->open) {
228 ret = dev->tr->open(dev);
229 if (ret)
230 goto error_put;
231 }
232
233 ret = __get_mtd_device(dev->mtd);
234 if (ret)
235 goto error_release;
236
237 unlock:
238 dev->open++;
239 mutex_unlock(&dev->lock);
240 blktrans_dev_put(dev);
241 return ret;
242
243 error_release:
244 if (dev->tr->release)
245 dev->tr->release(dev);
246 error_put:
247 module_put(dev->tr->owner);
248 kref_put(&dev->ref, blktrans_dev_release);
249 mutex_unlock(&dev->lock);
250 blktrans_dev_put(dev);
251 return ret;
252 }
253
blktrans_release(struct gendisk * disk,fmode_t mode)254 static int blktrans_release(struct gendisk *disk, fmode_t mode)
255 {
256 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
257 int ret = 0;
258
259 if (!dev)
260 return ret;
261
262 mutex_lock(&dev->lock);
263
264 if (--dev->open)
265 goto unlock;
266
267 kref_put(&dev->ref, blktrans_dev_release);
268 module_put(dev->tr->owner);
269
270 if (dev->mtd) {
271 ret = dev->tr->release ? dev->tr->release(dev) : 0;
272 __put_mtd_device(dev->mtd);
273 }
274 unlock:
275 mutex_unlock(&dev->lock);
276 blktrans_dev_put(dev);
277 return ret;
278 }
279
blktrans_getgeo(struct block_device * bdev,struct hd_geometry * geo)280 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
281 {
282 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
283 int ret = -ENXIO;
284
285 if (!dev)
286 return ret;
287
288 mutex_lock(&dev->lock);
289
290 if (!dev->mtd)
291 goto unlock;
292
293 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
294 unlock:
295 mutex_unlock(&dev->lock);
296 blktrans_dev_put(dev);
297 return ret;
298 }
299
blktrans_ioctl(struct block_device * bdev,fmode_t mode,unsigned int cmd,unsigned long arg)300 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
301 unsigned int cmd, unsigned long arg)
302 {
303 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
304 int ret = -ENXIO;
305
306 if (!dev)
307 return ret;
308
309 mutex_lock(&dev->lock);
310
311 if (!dev->mtd)
312 goto unlock;
313
314 switch (cmd) {
315 case BLKFLSBUF:
316 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
317 break;
318 default:
319 ret = -ENOTTY;
320 }
321 unlock:
322 mutex_unlock(&dev->lock);
323 blktrans_dev_put(dev);
324 return ret;
325 }
326
327 static const struct block_device_operations mtd_blktrans_ops = {
328 .owner = THIS_MODULE,
329 .open = blktrans_open,
330 .release = blktrans_release,
331 .ioctl = blktrans_ioctl,
332 .getgeo = blktrans_getgeo,
333 };
334
add_mtd_blktrans_dev(struct mtd_blktrans_dev * new)335 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
336 {
337 struct mtd_blktrans_ops *tr = new->tr;
338 struct mtd_blktrans_dev *d;
339 int last_devnum = -1;
340 struct gendisk *gd;
341 int ret;
342
343 if (mutex_trylock(&mtd_table_mutex)) {
344 mutex_unlock(&mtd_table_mutex);
345 BUG();
346 }
347
348 mutex_lock(&blktrans_ref_mutex);
349 list_for_each_entry(d, &tr->devs, list) {
350 if (new->devnum == -1) {
351 /* Use first free number */
352 if (d->devnum != last_devnum+1) {
353 /* Found a free devnum. Plug it in here */
354 new->devnum = last_devnum+1;
355 list_add_tail(&new->list, &d->list);
356 goto added;
357 }
358 } else if (d->devnum == new->devnum) {
359 /* Required number taken */
360 mutex_unlock(&blktrans_ref_mutex);
361 return -EBUSY;
362 } else if (d->devnum > new->devnum) {
363 /* Required number was free */
364 list_add_tail(&new->list, &d->list);
365 goto added;
366 }
367 last_devnum = d->devnum;
368 }
369
370 ret = -EBUSY;
371 if (new->devnum == -1)
372 new->devnum = last_devnum+1;
373
374 /* Check that the device and any partitions will get valid
375 * minor numbers and that the disk naming code below can cope
376 * with this number. */
377 if (new->devnum > (MINORMASK >> tr->part_bits) ||
378 (tr->part_bits && new->devnum >= 27 * 26)) {
379 mutex_unlock(&blktrans_ref_mutex);
380 goto error1;
381 }
382
383 list_add_tail(&new->list, &tr->devs);
384 added:
385 mutex_unlock(&blktrans_ref_mutex);
386
387 mutex_init(&new->lock);
388 kref_init(&new->ref);
389 if (!tr->writesect)
390 new->readonly = 1;
391
392 /* Create gendisk */
393 ret = -ENOMEM;
394 gd = alloc_disk(1 << tr->part_bits);
395
396 if (!gd)
397 goto error2;
398
399 new->disk = gd;
400 gd->private_data = new;
401 gd->major = tr->major;
402 gd->first_minor = (new->devnum) << tr->part_bits;
403 gd->fops = &mtd_blktrans_ops;
404
405 if (tr->part_bits)
406 if (new->devnum < 26)
407 snprintf(gd->disk_name, sizeof(gd->disk_name),
408 "%s%c", tr->name, 'a' + new->devnum);
409 else
410 snprintf(gd->disk_name, sizeof(gd->disk_name),
411 "%s%c%c", tr->name,
412 'a' - 1 + new->devnum / 26,
413 'a' + new->devnum % 26);
414 else
415 snprintf(gd->disk_name, sizeof(gd->disk_name),
416 "%s%d", tr->name, new->devnum);
417
418 set_capacity(gd, (new->size * tr->blksize) >> 9);
419
420 /* Create the request queue */
421 spin_lock_init(&new->queue_lock);
422 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
423
424 if (!new->rq)
425 goto error3;
426
427 new->rq->queuedata = new;
428 blk_queue_logical_block_size(new->rq, tr->blksize);
429
430 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
431
432 if (tr->discard) {
433 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
434 new->rq->limits.max_discard_sectors = UINT_MAX;
435 }
436
437 gd->queue = new->rq;
438
439 /* Create processing thread */
440 /* TODO: workqueue ? */
441 new->thread = kthread_run(mtd_blktrans_thread, new,
442 "%s%d", tr->name, new->mtd->index);
443 if (IS_ERR(new->thread)) {
444 ret = PTR_ERR(new->thread);
445 goto error4;
446 }
447 gd->driverfs_dev = &new->mtd->dev;
448
449 if (new->readonly)
450 set_disk_ro(gd, 1);
451
452 add_disk(gd);
453
454 if (new->disk_attributes) {
455 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
456 new->disk_attributes);
457 WARN_ON(ret);
458 }
459 return 0;
460 error4:
461 blk_cleanup_queue(new->rq);
462 error3:
463 put_disk(new->disk);
464 error2:
465 list_del(&new->list);
466 error1:
467 return ret;
468 }
469
del_mtd_blktrans_dev(struct mtd_blktrans_dev * old)470 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
471 {
472 unsigned long flags;
473
474 if (mutex_trylock(&mtd_table_mutex)) {
475 mutex_unlock(&mtd_table_mutex);
476 BUG();
477 }
478
479 if (old->disk_attributes)
480 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
481 old->disk_attributes);
482
483 /* Stop new requests to arrive */
484 del_gendisk(old->disk);
485
486
487 /* Stop the thread */
488 kthread_stop(old->thread);
489
490 /* Kill current requests */
491 spin_lock_irqsave(&old->queue_lock, flags);
492 old->rq->queuedata = NULL;
493 blk_start_queue(old->rq);
494 spin_unlock_irqrestore(&old->queue_lock, flags);
495
496 /* If the device is currently open, tell trans driver to close it,
497 then put mtd device, and don't touch it again */
498 mutex_lock(&old->lock);
499 if (old->open) {
500 if (old->tr->release)
501 old->tr->release(old);
502 __put_mtd_device(old->mtd);
503 }
504
505 old->mtd = NULL;
506
507 mutex_unlock(&old->lock);
508 blktrans_dev_put(old);
509 return 0;
510 }
511
blktrans_notify_remove(struct mtd_info * mtd)512 static void blktrans_notify_remove(struct mtd_info *mtd)
513 {
514 struct mtd_blktrans_ops *tr;
515 struct mtd_blktrans_dev *dev, *next;
516
517 list_for_each_entry(tr, &blktrans_majors, list)
518 list_for_each_entry_safe(dev, next, &tr->devs, list)
519 if (dev->mtd == mtd)
520 tr->remove_dev(dev);
521 }
522
blktrans_notify_add(struct mtd_info * mtd)523 static void blktrans_notify_add(struct mtd_info *mtd)
524 {
525 struct mtd_blktrans_ops *tr;
526
527 if (mtd->type == MTD_ABSENT)
528 return;
529
530 list_for_each_entry(tr, &blktrans_majors, list)
531 tr->add_mtd(tr, mtd);
532 }
533
534 static struct mtd_notifier blktrans_notifier = {
535 .add = blktrans_notify_add,
536 .remove = blktrans_notify_remove,
537 };
538
register_mtd_blktrans(struct mtd_blktrans_ops * tr)539 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
540 {
541 struct mtd_info *mtd;
542 int ret;
543
544 /* Register the notifier if/when the first device type is
545 registered, to prevent the link/init ordering from fucking
546 us over. */
547 if (!blktrans_notifier.list.next)
548 register_mtd_user(&blktrans_notifier);
549
550
551 mutex_lock(&mtd_table_mutex);
552
553 ret = register_blkdev(tr->major, tr->name);
554 if (ret < 0) {
555 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
556 tr->name, tr->major, ret);
557 mutex_unlock(&mtd_table_mutex);
558 return ret;
559 }
560
561 if (ret)
562 tr->major = ret;
563
564 tr->blkshift = ffs(tr->blksize) - 1;
565
566 INIT_LIST_HEAD(&tr->devs);
567 list_add(&tr->list, &blktrans_majors);
568
569 mtd_for_each_device(mtd)
570 if (mtd->type != MTD_ABSENT)
571 tr->add_mtd(tr, mtd);
572
573 mutex_unlock(&mtd_table_mutex);
574 return 0;
575 }
576
deregister_mtd_blktrans(struct mtd_blktrans_ops * tr)577 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
578 {
579 struct mtd_blktrans_dev *dev, *next;
580
581 mutex_lock(&mtd_table_mutex);
582
583 /* Remove it from the list of active majors */
584 list_del(&tr->list);
585
586 list_for_each_entry_safe(dev, next, &tr->devs, list)
587 tr->remove_dev(dev);
588
589 unregister_blkdev(tr->major, tr->name);
590 mutex_unlock(&mtd_table_mutex);
591
592 BUG_ON(!list_empty(&tr->devs));
593 return 0;
594 }
595
mtd_blktrans_exit(void)596 static void __exit mtd_blktrans_exit(void)
597 {
598 /* No race here -- if someone's currently in register_mtd_blktrans
599 we're screwed anyway. */
600 if (blktrans_notifier.list.next)
601 unregister_mtd_user(&blktrans_notifier);
602 }
603
604 module_exit(mtd_blktrans_exit);
605
606 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
607 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
608 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
609 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
610
611 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
612 MODULE_LICENSE("GPL");
613 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
614