?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
bpf: fix htab map destruction when extra reserve is in use
[linux/fpc-iii.git] / drivers / mtd / mtd_blkdevs.c
blob8d58acf33021b5aa8723d50501c30eb9f92ed352
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 <asm/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 int 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->cmd_type != REQ_TYPE_FS)
88 return -EIO;
89
90 if (req_op(req) == REQ_OP_FLUSH)
91 return tr->flush(dev);
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_op(req) == REQ_OP_DISCARD)
98 return tr->discard(dev, block, nsect);
99
100 if (rq_data_dir(req) == READ) {
101 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
102 if (tr->readsect(dev, block, buf))
103 return -EIO;
104 rq_flush_dcache_pages(req);
105 return 0;
106 } else {
107 if (!tr->writesect)
108 return -EIO;
109
110 rq_flush_dcache_pages(req);
111 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
112 if (tr->writesect(dev, block, buf))
113 return -EIO;
114 return 0;
115 }
116 }
117
118 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
119 {
120 return dev->bg_stop;
121 }
122 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
123
124 static void mtd_blktrans_work(struct work_struct *work)
125 {
126 struct mtd_blktrans_dev *dev =
127 container_of(work, struct mtd_blktrans_dev, work);
128 struct mtd_blktrans_ops *tr = dev->tr;
129 struct request_queue *rq = dev->rq;
130 struct request *req = NULL;
131 int background_done = 0;
132
133 spin_lock_irq(rq->queue_lock);
134
135 while (1) {
136 int res;
137
138 dev->bg_stop = false;
139 if (!req && !(req = blk_fetch_request(rq))) {
140 if (tr->background && !background_done) {
141 spin_unlock_irq(rq->queue_lock);
142 mutex_lock(&dev->lock);
143 tr->background(dev);
144 mutex_unlock(&dev->lock);
145 spin_lock_irq(rq->queue_lock);
146 /*
147 * Do background processing just once per idle
148 * period.
149 */
150 background_done = !dev->bg_stop;
151 continue;
152 }
153 break;
154 }
155
156 spin_unlock_irq(rq->queue_lock);
157
158 mutex_lock(&dev->lock);
159 res = do_blktrans_request(dev->tr, dev, req);
160 mutex_unlock(&dev->lock);
161
162 spin_lock_irq(rq->queue_lock);
163
164 if (!__blk_end_request_cur(req, res))
165 req = NULL;
166
167 background_done = 0;
168 }
169
170 spin_unlock_irq(rq->queue_lock);
171 }
172
173 static void mtd_blktrans_request(struct request_queue *rq)
174 {
175 struct mtd_blktrans_dev *dev;
176 struct request *req = NULL;
177
178 dev = rq->queuedata;
179
180 if (!dev)
181 while ((req = blk_fetch_request(rq)) != NULL)
182 __blk_end_request_all(req, -ENODEV);
183 else
184 queue_work(dev->wq, &dev->work);
185 }
186
187 static int blktrans_open(struct block_device *bdev, fmode_t mode)
188 {
189 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
190 int ret = 0;
191
192 if (!dev)
193 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
194
195 mutex_lock(&mtd_table_mutex);
196 mutex_lock(&dev->lock);
197
198 if (dev->open)
199 goto unlock;
200
201 kref_get(&dev->ref);
202 __module_get(dev->tr->owner);
203
204 if (!dev->mtd)
205 goto unlock;
206
207 if (dev->tr->open) {
208 ret = dev->tr->open(dev);
209 if (ret)
210 goto error_put;
211 }
212
213 ret = __get_mtd_device(dev->mtd);
214 if (ret)
215 goto error_release;
216 dev->file_mode = mode;
217
218 unlock:
219 dev->open++;
220 mutex_unlock(&dev->lock);
221 mutex_unlock(&mtd_table_mutex);
222 blktrans_dev_put(dev);
223 return ret;
224
225 error_release:
226 if (dev->tr->release)
227 dev->tr->release(dev);
228 error_put:
229 module_put(dev->tr->owner);
230 kref_put(&dev->ref, blktrans_dev_release);
231 mutex_unlock(&dev->lock);
232 mutex_unlock(&mtd_table_mutex);
233 blktrans_dev_put(dev);
234 return ret;
235 }
236
237 static void blktrans_release(struct gendisk *disk, fmode_t mode)
238 {
239 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
240
241 if (!dev)
242 return;
243
244 mutex_lock(&mtd_table_mutex);
245 mutex_lock(&dev->lock);
246
247 if (--dev->open)
248 goto unlock;
249
250 kref_put(&dev->ref, blktrans_dev_release);
251 module_put(dev->tr->owner);
252
253 if (dev->mtd) {
254 if (dev->tr->release)
255 dev->tr->release(dev);
256 __put_mtd_device(dev->mtd);
257 }
258 unlock:
259 mutex_unlock(&dev->lock);
260 mutex_unlock(&mtd_table_mutex);
261 blktrans_dev_put(dev);
262 }
263
264 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
265 {
266 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
267 int ret = -ENXIO;
268
269 if (!dev)
270 return ret;
271
272 mutex_lock(&dev->lock);
273
274 if (!dev->mtd)
275 goto unlock;
276
277 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
278 unlock:
279 mutex_unlock(&dev->lock);
280 blktrans_dev_put(dev);
281 return ret;
282 }
283
284 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
285 unsigned int cmd, unsigned long arg)
286 {
287 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
288 int ret = -ENXIO;
289
290 if (!dev)
291 return ret;
292
293 mutex_lock(&dev->lock);
294
295 if (!dev->mtd)
296 goto unlock;
297
298 switch (cmd) {
299 case BLKFLSBUF:
300 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
301 break;
302 default:
303 ret = -ENOTTY;
304 }
305 unlock:
306 mutex_unlock(&dev->lock);
307 blktrans_dev_put(dev);
308 return ret;
309 }
310
311 static const struct block_device_operations mtd_block_ops = {
312 .owner = THIS_MODULE,
313 .open = blktrans_open,
314 .release = blktrans_release,
315 .ioctl = blktrans_ioctl,
316 .getgeo = blktrans_getgeo,
317 };
318
319 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
320 {
321 struct mtd_blktrans_ops *tr = new->tr;
322 struct mtd_blktrans_dev *d;
323 int last_devnum = -1;
324 struct gendisk *gd;
325 int ret;
326
327 if (mutex_trylock(&mtd_table_mutex)) {
328 mutex_unlock(&mtd_table_mutex);
329 BUG();
330 }
331
332 mutex_lock(&blktrans_ref_mutex);
333 list_for_each_entry(d, &tr->devs, list) {
334 if (new->devnum == -1) {
335 /* Use first free number */
336 if (d->devnum != last_devnum+1) {
337 /* Found a free devnum. Plug it in here */
338 new->devnum = last_devnum+1;
339 list_add_tail(&new->list, &d->list);
340 goto added;
341 }
342 } else if (d->devnum == new->devnum) {
343 /* Required number taken */
344 mutex_unlock(&blktrans_ref_mutex);
345 return -EBUSY;
346 } else if (d->devnum > new->devnum) {
347 /* Required number was free */
348 list_add_tail(&new->list, &d->list);
349 goto added;
350 }
351 last_devnum = d->devnum;
352 }
353
354 ret = -EBUSY;
355 if (new->devnum == -1)
356 new->devnum = last_devnum+1;
357
358 /* Check that the device and any partitions will get valid
359 * minor numbers and that the disk naming code below can cope
360 * with this number. */
361 if (new->devnum > (MINORMASK >> tr->part_bits) ||
362 (tr->part_bits && new->devnum >= 27 * 26)) {
363 mutex_unlock(&blktrans_ref_mutex);
364 goto error1;
365 }
366
367 list_add_tail(&new->list, &tr->devs);
368 added:
369 mutex_unlock(&blktrans_ref_mutex);
370
371 mutex_init(&new->lock);
372 kref_init(&new->ref);
373 if (!tr->writesect)
374 new->readonly = 1;
375
376 /* Create gendisk */
377 ret = -ENOMEM;
378 gd = alloc_disk(1 << tr->part_bits);
379
380 if (!gd)
381 goto error2;
382
383 new->disk = gd;
384 gd->private_data = new;
385 gd->major = tr->major;
386 gd->first_minor = (new->devnum) << tr->part_bits;
387 gd->fops = &mtd_block_ops;
388
389 if (tr->part_bits)
390 if (new->devnum < 26)
391 snprintf(gd->disk_name, sizeof(gd->disk_name),
392 "%s%c", tr->name, 'a' + new->devnum);
393 else
394 snprintf(gd->disk_name, sizeof(gd->disk_name),
395 "%s%c%c", tr->name,
396 'a' - 1 + new->devnum / 26,
397 'a' + new->devnum % 26);
398 else
399 snprintf(gd->disk_name, sizeof(gd->disk_name),
400 "%s%d", tr->name, new->devnum);
401
402 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
403
404 /* Create the request queue */
405 spin_lock_init(&new->queue_lock);
406 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
407
408 if (!new->rq)
409 goto error3;
410
411 if (tr->flush)
412 blk_queue_write_cache(new->rq, true, false);
413
414 new->rq->queuedata = new;
415 blk_queue_logical_block_size(new->rq, tr->blksize);
416
417 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
418 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
419
420 if (tr->discard) {
421 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
422 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
423 }
424
425 gd->queue = new->rq;
426
427 /* Create processing workqueue */
428 new->wq = alloc_workqueue("%s%d", 0, 0,
429 tr->name, new->mtd->index);
430 if (!new->wq)
431 goto error4;
432 INIT_WORK(&new->work, mtd_blktrans_work);
433
434 if (new->readonly)
435 set_disk_ro(gd, 1);
436
437 device_add_disk(&new->mtd->dev, gd);
438
439 if (new->disk_attributes) {
440 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
441 new->disk_attributes);
442 WARN_ON(ret);
443 }
444 return 0;
445 error4:
446 blk_cleanup_queue(new->rq);
447 error3:
448 put_disk(new->disk);
449 error2:
450 list_del(&new->list);
451 error1:
452 return ret;
453 }
454
455 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
456 {
457 unsigned long flags;
458
459 if (mutex_trylock(&mtd_table_mutex)) {
460 mutex_unlock(&mtd_table_mutex);
461 BUG();
462 }
463
464 if (old->disk_attributes)
465 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
466 old->disk_attributes);
467
468 /* Stop new requests to arrive */
469 del_gendisk(old->disk);
470
471 /* Stop workqueue. This will perform any pending request. */
472 destroy_workqueue(old->wq);
473
474 /* Kill current requests */
475 spin_lock_irqsave(&old->queue_lock, flags);
476 old->rq->queuedata = NULL;
477 blk_start_queue(old->rq);
478 spin_unlock_irqrestore(&old->queue_lock, flags);
479
480 /* If the device is currently open, tell trans driver to close it,
481 then put mtd device, and don't touch it again */
482 mutex_lock(&old->lock);
483 if (old->open) {
484 if (old->tr->release)
485 old->tr->release(old);
486 __put_mtd_device(old->mtd);
487 }
488
489 old->mtd = NULL;
490
491 mutex_unlock(&old->lock);
492 blktrans_dev_put(old);
493 return 0;
494 }
495
496 static void blktrans_notify_remove(struct mtd_info *mtd)
497 {
498 struct mtd_blktrans_ops *tr;
499 struct mtd_blktrans_dev *dev, *next;
500
501 list_for_each_entry(tr, &blktrans_majors, list)
502 list_for_each_entry_safe(dev, next, &tr->devs, list)
503 if (dev->mtd == mtd)
504 tr->remove_dev(dev);
505 }
506
507 static void blktrans_notify_add(struct mtd_info *mtd)
508 {
509 struct mtd_blktrans_ops *tr;
510
511 if (mtd->type == MTD_ABSENT)
512 return;
513
514 list_for_each_entry(tr, &blktrans_majors, list)
515 tr->add_mtd(tr, mtd);
516 }
517
518 static struct mtd_notifier blktrans_notifier = {
519 .add = blktrans_notify_add,
520 .remove = blktrans_notify_remove,
521 };
522
523 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
524 {
525 struct mtd_info *mtd;
526 int ret;
527
528 /* Register the notifier if/when the first device type is
529 registered, to prevent the link/init ordering from fucking
530 us over. */
531 if (!blktrans_notifier.list.next)
532 register_mtd_user(&blktrans_notifier);
533
534
535 mutex_lock(&mtd_table_mutex);
536
537 ret = register_blkdev(tr->major, tr->name);
538 if (ret < 0) {
539 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
540 tr->name, tr->major, ret);
541 mutex_unlock(&mtd_table_mutex);
542 return ret;
543 }
544
545 if (ret)
546 tr->major = ret;
547
548 tr->blkshift = ffs(tr->blksize) - 1;
549
550 INIT_LIST_HEAD(&tr->devs);
551 list_add(&tr->list, &blktrans_majors);
552
553 mtd_for_each_device(mtd)
554 if (mtd->type != MTD_ABSENT)
555 tr->add_mtd(tr, mtd);
556
557 mutex_unlock(&mtd_table_mutex);
558 return 0;
559 }
560
561 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
562 {
563 struct mtd_blktrans_dev *dev, *next;
564
565 mutex_lock(&mtd_table_mutex);
566
567 /* Remove it from the list of active majors */
568 list_del(&tr->list);
569
570 list_for_each_entry_safe(dev, next, &tr->devs, list)
571 tr->remove_dev(dev);
572
573 unregister_blkdev(tr->major, tr->name);
574 mutex_unlock(&mtd_table_mutex);
575
576 BUG_ON(!list_empty(&tr->devs));
577 return 0;
578 }
579
580 static void __exit mtd_blktrans_exit(void)
581 {
582 /* No race here -- if someone's currently in register_mtd_blktrans
583 we're screwed anyway. */
584 if (blktrans_notifier.list.next)
585 unregister_mtd_user(&blktrans_notifier);
586 }
587
588 module_exit(mtd_blktrans_exit);
589
590 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
591 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
592 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
593 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
594
595 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
596 MODULE_LICENSE("GPL");
597 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
Linux with added FPC-III support