mtd: blkdevs: Fix mtd block write failure
[karo-tx-linux.git] / drivers / mtd / mtd_blkdevs.c
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/mutex.h>
34 #include <linux/uaccess.h>
35
36 #include "mtdcore.h"
37
38 static LIST_HEAD(blktrans_majors);
39 static DEFINE_MUTEX(blktrans_ref_mutex);
40
41 static void blktrans_dev_release(struct kref *kref)
42 {
43         struct mtd_blktrans_dev *dev =
44                 container_of(kref, struct mtd_blktrans_dev, ref);
45
46         dev->disk->private_data = NULL;
47         blk_cleanup_queue(dev->rq);
48         put_disk(dev->disk);
49         list_del(&dev->list);
50         kfree(dev);
51 }
52
53 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
54 {
55         struct mtd_blktrans_dev *dev;
56
57         mutex_lock(&blktrans_ref_mutex);
58         dev = disk->private_data;
59
60         if (!dev)
61                 goto unlock;
62         kref_get(&dev->ref);
63 unlock:
64         mutex_unlock(&blktrans_ref_mutex);
65         return dev;
66 }
67
68 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
69 {
70         mutex_lock(&blktrans_ref_mutex);
71         kref_put(&dev->ref, blktrans_dev_release);
72         mutex_unlock(&blktrans_ref_mutex);
73 }
74
75
76 static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
77                                struct mtd_blktrans_dev *dev,
78                                struct request *req)
79 {
80         unsigned long block, nsect;
81         char *buf;
82
83         block = blk_rq_pos(req) << 9 >> tr->blkshift;
84         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
85         buf = bio_data(req->bio);
86
87         if (req_op(req) == REQ_OP_FLUSH) {
88                 if (tr->flush(dev))
89                         return BLK_STS_IOERR;
90                 return BLK_STS_OK;
91         }
92
93         if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
94             get_capacity(req->rq_disk))
95                 return BLK_STS_IOERR;
96
97         switch (req_op(req)) {
98         case REQ_OP_DISCARD:
99                 if (tr->discard(dev, block, nsect))
100                         return BLK_STS_IOERR;
101                 return BLK_STS_OK;
102         case REQ_OP_READ:
103                 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
104                         if (tr->readsect(dev, block, buf))
105                                 return BLK_STS_IOERR;
106                 rq_flush_dcache_pages(req);
107                 return BLK_STS_OK;
108         case REQ_OP_WRITE:
109                 if (!tr->writesect)
110                         return BLK_STS_IOERR;
111
112                 rq_flush_dcache_pages(req);
113                 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
114                         if (tr->writesect(dev, block, buf))
115                                 return BLK_STS_IOERR;
116                 return BLK_STS_OK;
117         default:
118                 return BLK_STS_IOERR;
119         }
120 }
121
122 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
123 {
124         return dev->bg_stop;
125 }
126 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
127
128 static void mtd_blktrans_work(struct work_struct *work)
129 {
130         struct mtd_blktrans_dev *dev =
131                 container_of(work, struct mtd_blktrans_dev, work);
132         struct mtd_blktrans_ops *tr = dev->tr;
133         struct request_queue *rq = dev->rq;
134         struct request *req = NULL;
135         int background_done = 0;
136
137         spin_lock_irq(rq->queue_lock);
138
139         while (1) {
140                 blk_status_t res;
141
142                 dev->bg_stop = false;
143                 if (!req && !(req = blk_fetch_request(rq))) {
144                         if (tr->background && !background_done) {
145                                 spin_unlock_irq(rq->queue_lock);
146                                 mutex_lock(&dev->lock);
147                                 tr->background(dev);
148                                 mutex_unlock(&dev->lock);
149                                 spin_lock_irq(rq->queue_lock);
150                                 /*
151                                  * Do background processing just once per idle
152                                  * period.
153                                  */
154                                 background_done = !dev->bg_stop;
155                                 continue;
156                         }
157                         break;
158                 }
159
160                 spin_unlock_irq(rq->queue_lock);
161
162                 mutex_lock(&dev->lock);
163                 res = do_blktrans_request(dev->tr, dev, req);
164                 mutex_unlock(&dev->lock);
165
166                 spin_lock_irq(rq->queue_lock);
167
168                 if (!__blk_end_request_cur(req, res))
169                         req = NULL;
170
171                 background_done = 0;
172         }
173
174         spin_unlock_irq(rq->queue_lock);
175 }
176
177 static void mtd_blktrans_request(struct request_queue *rq)
178 {
179         struct mtd_blktrans_dev *dev;
180         struct request *req = NULL;
181
182         dev = rq->queuedata;
183
184         if (!dev)
185                 while ((req = blk_fetch_request(rq)) != NULL)
186                         __blk_end_request_all(req, BLK_STS_IOERR);
187         else
188                 queue_work(dev->wq, &dev->work);
189 }
190
191 static int blktrans_open(struct block_device *bdev, fmode_t mode)
192 {
193         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
194         int ret = 0;
195
196         if (!dev)
197                 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
198
199         mutex_lock(&mtd_table_mutex);
200         mutex_lock(&dev->lock);
201
202         if (dev->open)
203                 goto unlock;
204
205         kref_get(&dev->ref);
206         __module_get(dev->tr->owner);
207
208         if (!dev->mtd)
209                 goto unlock;
210
211         if (dev->tr->open) {
212                 ret = dev->tr->open(dev);
213                 if (ret)
214                         goto error_put;
215         }
216
217         ret = __get_mtd_device(dev->mtd);
218         if (ret)
219                 goto error_release;
220         dev->file_mode = mode;
221
222 unlock:
223         dev->open++;
224         mutex_unlock(&dev->lock);
225         mutex_unlock(&mtd_table_mutex);
226         blktrans_dev_put(dev);
227         return ret;
228
229 error_release:
230         if (dev->tr->release)
231                 dev->tr->release(dev);
232 error_put:
233         module_put(dev->tr->owner);
234         kref_put(&dev->ref, blktrans_dev_release);
235         mutex_unlock(&dev->lock);
236         mutex_unlock(&mtd_table_mutex);
237         blktrans_dev_put(dev);
238         return ret;
239 }
240
241 static void blktrans_release(struct gendisk *disk, fmode_t mode)
242 {
243         struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
244
245         if (!dev)
246                 return;
247
248         mutex_lock(&mtd_table_mutex);
249         mutex_lock(&dev->lock);
250
251         if (--dev->open)
252                 goto unlock;
253
254         kref_put(&dev->ref, blktrans_dev_release);
255         module_put(dev->tr->owner);
256
257         if (dev->mtd) {
258                 if (dev->tr->release)
259                         dev->tr->release(dev);
260                 __put_mtd_device(dev->mtd);
261         }
262 unlock:
263         mutex_unlock(&dev->lock);
264         mutex_unlock(&mtd_table_mutex);
265         blktrans_dev_put(dev);
266 }
267
268 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
269 {
270         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
271         int ret = -ENXIO;
272
273         if (!dev)
274                 return ret;
275
276         mutex_lock(&dev->lock);
277
278         if (!dev->mtd)
279                 goto unlock;
280
281         ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
282 unlock:
283         mutex_unlock(&dev->lock);
284         blktrans_dev_put(dev);
285         return ret;
286 }
287
288 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
289                               unsigned int cmd, unsigned long arg)
290 {
291         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
292         int ret = -ENXIO;
293
294         if (!dev)
295                 return ret;
296
297         mutex_lock(&dev->lock);
298
299         if (!dev->mtd)
300                 goto unlock;
301
302         switch (cmd) {
303         case BLKFLSBUF:
304                 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
305                 break;
306         default:
307                 ret = -ENOTTY;
308         }
309 unlock:
310         mutex_unlock(&dev->lock);
311         blktrans_dev_put(dev);
312         return ret;
313 }
314
315 static const struct block_device_operations mtd_block_ops = {
316         .owner          = THIS_MODULE,
317         .open           = blktrans_open,
318         .release        = blktrans_release,
319         .ioctl          = blktrans_ioctl,
320         .getgeo         = blktrans_getgeo,
321 };
322
323 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
324 {
325         struct mtd_blktrans_ops *tr = new->tr;
326         struct mtd_blktrans_dev *d;
327         int last_devnum = -1;
328         struct gendisk *gd;
329         int ret;
330
331         if (mutex_trylock(&mtd_table_mutex)) {
332                 mutex_unlock(&mtd_table_mutex);
333                 BUG();
334         }
335
336         mutex_lock(&blktrans_ref_mutex);
337         list_for_each_entry(d, &tr->devs, list) {
338                 if (new->devnum == -1) {
339                         /* Use first free number */
340                         if (d->devnum != last_devnum+1) {
341                                 /* Found a free devnum. Plug it in here */
342                                 new->devnum = last_devnum+1;
343                                 list_add_tail(&new->list, &d->list);
344                                 goto added;
345                         }
346                 } else if (d->devnum == new->devnum) {
347                         /* Required number taken */
348                         mutex_unlock(&blktrans_ref_mutex);
349                         return -EBUSY;
350                 } else if (d->devnum > new->devnum) {
351                         /* Required number was free */
352                         list_add_tail(&new->list, &d->list);
353                         goto added;
354                 }
355                 last_devnum = d->devnum;
356         }
357
358         ret = -EBUSY;
359         if (new->devnum == -1)
360                 new->devnum = last_devnum+1;
361
362         /* Check that the device and any partitions will get valid
363          * minor numbers and that the disk naming code below can cope
364          * with this number. */
365         if (new->devnum > (MINORMASK >> tr->part_bits) ||
366             (tr->part_bits && new->devnum >= 27 * 26)) {
367                 mutex_unlock(&blktrans_ref_mutex);
368                 goto error1;
369         }
370
371         list_add_tail(&new->list, &tr->devs);
372  added:
373         mutex_unlock(&blktrans_ref_mutex);
374
375         mutex_init(&new->lock);
376         kref_init(&new->ref);
377         if (!tr->writesect)
378                 new->readonly = 1;
379
380         /* Create gendisk */
381         ret = -ENOMEM;
382         gd = alloc_disk(1 << tr->part_bits);
383
384         if (!gd)
385                 goto error2;
386
387         new->disk = gd;
388         gd->private_data = new;
389         gd->major = tr->major;
390         gd->first_minor = (new->devnum) << tr->part_bits;
391         gd->fops = &mtd_block_ops;
392
393         if (tr->part_bits)
394                 if (new->devnum < 26)
395                         snprintf(gd->disk_name, sizeof(gd->disk_name),
396                                  "%s%c", tr->name, 'a' + new->devnum);
397                 else
398                         snprintf(gd->disk_name, sizeof(gd->disk_name),
399                                  "%s%c%c", tr->name,
400                                  'a' - 1 + new->devnum / 26,
401                                  'a' + new->devnum % 26);
402         else
403                 snprintf(gd->disk_name, sizeof(gd->disk_name),
404                          "%s%d", tr->name, new->devnum);
405
406         set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
407
408         /* Create the request queue */
409         spin_lock_init(&new->queue_lock);
410         new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
411
412         if (!new->rq)
413                 goto error3;
414
415         if (tr->flush)
416                 blk_queue_write_cache(new->rq, true, false);
417
418         new->rq->queuedata = new;
419         blk_queue_logical_block_size(new->rq, tr->blksize);
420
421         blk_queue_bounce_limit(new->rq, BLK_BOUNCE_HIGH);
422         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
423         queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
424
425         if (tr->discard) {
426                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
427                 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
428         }
429
430         gd->queue = new->rq;
431
432         /* Create processing workqueue */
433         new->wq = alloc_workqueue("%s%d", 0, 0,
434                                   tr->name, new->mtd->index);
435         if (!new->wq)
436                 goto error4;
437         INIT_WORK(&new->work, mtd_blktrans_work);
438
439         if (new->readonly)
440                 set_disk_ro(gd, 1);
441
442         device_add_disk(&new->mtd->dev, gd);
443
444         if (new->disk_attributes) {
445                 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
446                                         new->disk_attributes);
447                 WARN_ON(ret);
448         }
449         return 0;
450 error4:
451         blk_cleanup_queue(new->rq);
452 error3:
453         put_disk(new->disk);
454 error2:
455         list_del(&new->list);
456 error1:
457         return ret;
458 }
459
460 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
461 {
462         unsigned long flags;
463
464         if (mutex_trylock(&mtd_table_mutex)) {
465                 mutex_unlock(&mtd_table_mutex);
466                 BUG();
467         }
468
469         if (old->disk_attributes)
470                 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
471                                                 old->disk_attributes);
472
473         /* Stop new requests to arrive */
474         del_gendisk(old->disk);
475
476         /* Stop workqueue. This will perform any pending request. */
477         destroy_workqueue(old->wq);
478
479         /* Kill current requests */
480         spin_lock_irqsave(&old->queue_lock, flags);
481         old->rq->queuedata = NULL;
482         blk_start_queue(old->rq);
483         spin_unlock_irqrestore(&old->queue_lock, flags);
484
485         /* If the device is currently open, tell trans driver to close it,
486                 then put mtd device, and don't touch it again */
487         mutex_lock(&old->lock);
488         if (old->open) {
489                 if (old->tr->release)
490                         old->tr->release(old);
491                 __put_mtd_device(old->mtd);
492         }
493
494         old->mtd = NULL;
495
496         mutex_unlock(&old->lock);
497         blktrans_dev_put(old);
498         return 0;
499 }
500
501 static void blktrans_notify_remove(struct mtd_info *mtd)
502 {
503         struct mtd_blktrans_ops *tr;
504         struct mtd_blktrans_dev *dev, *next;
505
506         list_for_each_entry(tr, &blktrans_majors, list)
507                 list_for_each_entry_safe(dev, next, &tr->devs, list)
508                         if (dev->mtd == mtd)
509                                 tr->remove_dev(dev);
510 }
511
512 static void blktrans_notify_add(struct mtd_info *mtd)
513 {
514         struct mtd_blktrans_ops *tr;
515
516         if (mtd->type == MTD_ABSENT)
517                 return;
518
519         list_for_each_entry(tr, &blktrans_majors, list)
520                 tr->add_mtd(tr, mtd);
521 }
522
523 static struct mtd_notifier blktrans_notifier = {
524         .add = blktrans_notify_add,
525         .remove = blktrans_notify_remove,
526 };
527
528 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
529 {
530         struct mtd_info *mtd;
531         int ret;
532
533         /* Register the notifier if/when the first device type is
534            registered, to prevent the link/init ordering from fucking
535            us over. */
536         if (!blktrans_notifier.list.next)
537                 register_mtd_user(&blktrans_notifier);
538
539
540         mutex_lock(&mtd_table_mutex);
541
542         ret = register_blkdev(tr->major, tr->name);
543         if (ret < 0) {
544                 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
545                        tr->name, tr->major, ret);
546                 mutex_unlock(&mtd_table_mutex);
547                 return ret;
548         }
549
550         if (ret)
551                 tr->major = ret;
552
553         tr->blkshift = ffs(tr->blksize) - 1;
554
555         INIT_LIST_HEAD(&tr->devs);
556         list_add(&tr->list, &blktrans_majors);
557
558         mtd_for_each_device(mtd)
559                 if (mtd->type != MTD_ABSENT)
560                         tr->add_mtd(tr, mtd);
561
562         mutex_unlock(&mtd_table_mutex);
563         return 0;
564 }
565
566 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
567 {
568         struct mtd_blktrans_dev *dev, *next;
569
570         mutex_lock(&mtd_table_mutex);
571
572         /* Remove it from the list of active majors */
573         list_del(&tr->list);
574
575         list_for_each_entry_safe(dev, next, &tr->devs, list)
576                 tr->remove_dev(dev);
577
578         unregister_blkdev(tr->major, tr->name);
579         mutex_unlock(&mtd_table_mutex);
580
581         BUG_ON(!list_empty(&tr->devs));
582         return 0;
583 }
584
585 static void __exit mtd_blktrans_exit(void)
586 {
587         /* No race here -- if someone's currently in register_mtd_blktrans
588            we're screwed anyway. */
589         if (blktrans_notifier.list.next)
590                 unregister_mtd_user(&blktrans_notifier);
591 }
592
593 module_exit(mtd_blktrans_exit);
594
595 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
596 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
597 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
598 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
599
600 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
601 MODULE_LICENSE("GPL");
602 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");