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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 <asm/uaccess.h> |
36 | |
37 | #include "mtdcore.h" |
38 | |
39 | static LIST_HEAD(blktrans_majors); |
40 | static DEFINE_MUTEX(blktrans_ref_mutex); |
41 | |
42 | static void blktrans_dev_release(struct kref *kref) |
43 | { |
44 | struct mtd_blktrans_dev *dev = |
45 | container_of(kref, struct mtd_blktrans_dev, ref); |
46 | |
47 | dev->disk->private_data = NULL; |
48 | blk_cleanup_queue(dev->rq); |
49 | put_disk(dev->disk); |
50 | list_del(&dev->list); |
51 | kfree(dev); |
52 | } |
53 | |
54 | static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk) |
55 | { |
56 | struct mtd_blktrans_dev *dev; |
57 | |
58 | mutex_lock(&blktrans_ref_mutex); |
59 | dev = disk->private_data; |
60 | |
61 | if (!dev) |
62 | goto unlock; |
63 | kref_get(&dev->ref); |
64 | unlock: |
65 | mutex_unlock(&blktrans_ref_mutex); |
66 | return dev; |
67 | } |
68 | |
69 | static void blktrans_dev_put(struct mtd_blktrans_dev *dev) |
70 | { |
71 | mutex_lock(&blktrans_ref_mutex); |
72 | kref_put(&dev->ref, blktrans_dev_release); |
73 | mutex_unlock(&blktrans_ref_mutex); |
74 | } |
75 | |
76 | |
77 | static int do_blktrans_request(struct mtd_blktrans_ops *tr, |
78 | struct mtd_blktrans_dev *dev, |
79 | struct request *req) |
80 | { |
81 | unsigned long block, nsect; |
82 | char *buf; |
83 | |
84 | block = blk_rq_pos(req) << 9 >> tr->blkshift; |
85 | nsect = blk_rq_cur_bytes(req) >> tr->blkshift; |
86 | |
87 | buf = req->buffer; |
88 | |
89 | if (req->cmd_type != REQ_TYPE_FS) |
90 | return -EIO; |
91 | |
92 | if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > |
93 | get_capacity(req->rq_disk)) |
94 | return -EIO; |
95 | |
96 | if (req->cmd_flags & REQ_DISCARD) |
97 | return tr->discard(dev, block, nsect); |
98 | |
99 | switch(rq_data_dir(req)) { |
100 | case 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 | case WRITE: |
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 | default: |
116 | printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req)); |
117 | return -EIO; |
118 | } |
119 | } |
120 | |
121 | int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) |
122 | { |
123 | return dev->bg_stop; |
124 | } |
125 | EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); |
126 | |
127 | static void mtd_blktrans_work(struct work_struct *work) |
128 | { |
129 | struct mtd_blktrans_dev *dev = |
130 | container_of(work, struct mtd_blktrans_dev, work); |
131 | struct mtd_blktrans_ops *tr = dev->tr; |
132 | struct request_queue *rq = dev->rq; |
133 | struct request *req = NULL; |
134 | int background_done = 0; |
135 | |
136 | spin_lock_irq(rq->queue_lock); |
137 | |
138 | while (1) { |
139 | int res; |
140 | |
141 | dev->bg_stop = false; |
142 | if (!req && !(req = blk_fetch_request(rq))) { |
143 | if (tr->background && !background_done) { |
144 | spin_unlock_irq(rq->queue_lock); |
145 | mutex_lock(&dev->lock); |
146 | tr->background(dev); |
147 | mutex_unlock(&dev->lock); |
148 | spin_lock_irq(rq->queue_lock); |
149 | /* |
150 | * Do background processing just once per idle |
151 | * period. |
152 | */ |
153 | background_done = !dev->bg_stop; |
154 | continue; |
155 | } |
156 | break; |
157 | } |
158 | |
159 | spin_unlock_irq(rq->queue_lock); |
160 | |
161 | mutex_lock(&dev->lock); |
162 | res = do_blktrans_request(dev->tr, dev, req); |
163 | mutex_unlock(&dev->lock); |
164 | |
165 | spin_lock_irq(rq->queue_lock); |
166 | |
167 | if (!__blk_end_request_cur(req, res)) |
168 | req = NULL; |
169 | |
170 | background_done = 0; |
171 | } |
172 | |
173 | if (req) |
174 | __blk_end_request_all(req, -EIO); |
175 | |
176 | spin_unlock_irq(rq->queue_lock); |
177 | } |
178 | |
179 | static void mtd_blktrans_request(struct request_queue *rq) |
180 | { |
181 | struct mtd_blktrans_dev *dev; |
182 | struct request *req = NULL; |
183 | |
184 | dev = rq->queuedata; |
185 | |
186 | if (!dev) |
187 | while ((req = blk_fetch_request(rq)) != NULL) |
188 | __blk_end_request_all(req, -ENODEV); |
189 | else |
190 | queue_work(dev->wq, &dev->work); |
191 | } |
192 | |
193 | static int blktrans_open(struct block_device *bdev, fmode_t mode) |
194 | { |
195 | struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); |
196 | int ret = 0; |
197 | |
198 | if (!dev) |
199 | return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ |
200 | |
201 | mutex_lock(&dev->lock); |
202 | |
203 | if (dev->open) |
204 | goto unlock; |
205 | |
206 | kref_get(&dev->ref); |
207 | __module_get(dev->tr->owner); |
208 | |
209 | if (!dev->mtd) |
210 | goto unlock; |
211 | |
212 | if (dev->tr->open) { |
213 | ret = dev->tr->open(dev); |
214 | if (ret) |
215 | goto error_put; |
216 | } |
217 | |
218 | ret = __get_mtd_device(dev->mtd); |
219 | if (ret) |
220 | goto error_release; |
221 | dev->file_mode = mode; |
222 | |
223 | unlock: |
224 | dev->open++; |
225 | mutex_unlock(&dev->lock); |
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 | blktrans_dev_put(dev); |
237 | return ret; |
238 | } |
239 | |
240 | static int blktrans_release(struct gendisk *disk, fmode_t mode) |
241 | { |
242 | struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); |
243 | int ret = 0; |
244 | |
245 | if (!dev) |
246 | return ret; |
247 | |
248 | mutex_lock(&dev->lock); |
249 | |
250 | if (--dev->open) |
251 | goto unlock; |
252 | |
253 | kref_put(&dev->ref, blktrans_dev_release); |
254 | module_put(dev->tr->owner); |
255 | |
256 | if (dev->mtd) { |
257 | ret = dev->tr->release ? dev->tr->release(dev) : 0; |
258 | __put_mtd_device(dev->mtd); |
259 | } |
260 | unlock: |
261 | mutex_unlock(&dev->lock); |
262 | blktrans_dev_put(dev); |
263 | return ret; |
264 | } |
265 | |
266 | static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) |
267 | { |
268 | struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); |
269 | int ret = -ENXIO; |
270 | |
271 | if (!dev) |
272 | return ret; |
273 | |
274 | mutex_lock(&dev->lock); |
275 | |
276 | if (!dev->mtd) |
277 | goto unlock; |
278 | |
279 | ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; |
280 | unlock: |
281 | mutex_unlock(&dev->lock); |
282 | blktrans_dev_put(dev); |
283 | return ret; |
284 | } |
285 | |
286 | static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, |
287 | unsigned int cmd, unsigned long arg) |
288 | { |
289 | struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); |
290 | int ret = -ENXIO; |
291 | |
292 | if (!dev) |
293 | return ret; |
294 | |
295 | mutex_lock(&dev->lock); |
296 | |
297 | if (!dev->mtd) |
298 | goto unlock; |
299 | |
300 | switch (cmd) { |
301 | case BLKFLSBUF: |
302 | ret = dev->tr->flush ? dev->tr->flush(dev) : 0; |
303 | break; |
304 | default: |
305 | ret = -ENOTTY; |
306 | } |
307 | unlock: |
308 | mutex_unlock(&dev->lock); |
309 | blktrans_dev_put(dev); |
310 | return ret; |
311 | } |
312 | |
313 | static const struct block_device_operations mtd_block_ops = { |
314 | .owner = THIS_MODULE, |
315 | .open = blktrans_open, |
316 | .release = blktrans_release, |
317 | .ioctl = blktrans_ioctl, |
318 | .getgeo = blktrans_getgeo, |
319 | }; |
320 | |
321 | int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) |
322 | { |
323 | struct mtd_blktrans_ops *tr = new->tr; |
324 | struct mtd_blktrans_dev *d; |
325 | int last_devnum = -1; |
326 | struct gendisk *gd; |
327 | int ret; |
328 | |
329 | if (mutex_trylock(&mtd_table_mutex)) { |
330 | mutex_unlock(&mtd_table_mutex); |
331 | BUG(); |
332 | } |
333 | |
334 | mutex_lock(&blktrans_ref_mutex); |
335 | list_for_each_entry(d, &tr->devs, list) { |
336 | if (new->devnum == -1) { |
337 | /* Use first free number */ |
338 | if (d->devnum != last_devnum+1) { |
339 | /* Found a free devnum. Plug it in here */ |
340 | new->devnum = last_devnum+1; |
341 | list_add_tail(&new->list, &d->list); |
342 | goto added; |
343 | } |
344 | } else if (d->devnum == new->devnum) { |
345 | /* Required number taken */ |
346 | mutex_unlock(&blktrans_ref_mutex); |
347 | return -EBUSY; |
348 | } else if (d->devnum > new->devnum) { |
349 | /* Required number was free */ |
350 | list_add_tail(&new->list, &d->list); |
351 | goto added; |
352 | } |
353 | last_devnum = d->devnum; |
354 | } |
355 | |
356 | ret = -EBUSY; |
357 | if (new->devnum == -1) |
358 | new->devnum = last_devnum+1; |
359 | |
360 | /* Check that the device and any partitions will get valid |
361 | * minor numbers and that the disk naming code below can cope |
362 | * with this number. */ |
363 | if (new->devnum > (MINORMASK >> tr->part_bits) || |
364 | (tr->part_bits && new->devnum >= 27 * 26)) { |
365 | mutex_unlock(&blktrans_ref_mutex); |
366 | goto error1; |
367 | } |
368 | |
369 | list_add_tail(&new->list, &tr->devs); |
370 | added: |
371 | mutex_unlock(&blktrans_ref_mutex); |
372 | |
373 | mutex_init(&new->lock); |
374 | kref_init(&new->ref); |
375 | if (!tr->writesect) |
376 | new->readonly = 1; |
377 | |
378 | /* Create gendisk */ |
379 | ret = -ENOMEM; |
380 | gd = alloc_disk(1 << tr->part_bits); |
381 | |
382 | if (!gd) |
383 | goto error2; |
384 | |
385 | new->disk = gd; |
386 | gd->private_data = new; |
387 | gd->major = tr->major; |
388 | gd->first_minor = (new->devnum) << tr->part_bits; |
389 | gd->fops = &mtd_block_ops; |
390 | |
391 | if (tr->part_bits) |
392 | if (new->devnum < 26) |
393 | snprintf(gd->disk_name, sizeof(gd->disk_name), |
394 | "%s%c", tr->name, 'a' + new->devnum); |
395 | else |
396 | snprintf(gd->disk_name, sizeof(gd->disk_name), |
397 | "%s%c%c", tr->name, |
398 | 'a' - 1 + new->devnum / 26, |
399 | 'a' + new->devnum % 26); |
400 | else |
401 | snprintf(gd->disk_name, sizeof(gd->disk_name), |
402 | "%s%d", tr->name, new->devnum); |
403 | |
404 | set_capacity(gd, (new->size * tr->blksize) >> 9); |
405 | |
406 | /* Create the request queue */ |
407 | spin_lock_init(&new->queue_lock); |
408 | new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); |
409 | |
410 | if (!new->rq) |
411 | goto error3; |
412 | |
413 | new->rq->queuedata = new; |
414 | blk_queue_logical_block_size(new->rq, tr->blksize); |
415 | |
416 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); |
417 | |
418 | if (tr->discard) { |
419 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); |
420 | new->rq->limits.max_discard_sectors = UINT_MAX; |
421 | } |
422 | |
423 | gd->queue = new->rq; |
424 | |
425 | /* Create processing workqueue */ |
426 | new->wq = alloc_workqueue("%s%d", 0, 0, |
427 | tr->name, new->mtd->index); |
428 | if (!new->wq) |
429 | goto error4; |
430 | INIT_WORK(&new->work, mtd_blktrans_work); |
431 | |
432 | gd->driverfs_dev = &new->mtd->dev; |
433 | |
434 | if (new->readonly) |
435 | set_disk_ro(gd, 1); |
436 | |
437 | add_disk(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'"); |
598 |
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