1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Interface to Linux block layer for MTD 'translation layers'. |
4 | * |
5 | * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org> |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/slab.h> |
10 | #include <linux/module.h> |
11 | #include <linux/list.h> |
12 | #include <linux/fs.h> |
13 | #include <linux/mtd/blktrans.h> |
14 | #include <linux/mtd/mtd.h> |
15 | #include <linux/blkdev.h> |
16 | #include <linux/blk-mq.h> |
17 | #include <linux/blkpg.h> |
18 | #include <linux/spinlock.h> |
19 | #include <linux/hdreg.h> |
20 | #include <linux/mutex.h> |
21 | #include <linux/uaccess.h> |
22 | |
23 | #include "mtdcore.h" |
24 | |
25 | static LIST_HEAD(blktrans_majors); |
26 | |
27 | static void blktrans_dev_release(struct kref *kref) |
28 | { |
29 | struct mtd_blktrans_dev *dev = |
30 | container_of(kref, struct mtd_blktrans_dev, ref); |
31 | |
32 | put_disk(disk: dev->disk); |
33 | blk_mq_free_tag_set(set: dev->tag_set); |
34 | kfree(objp: dev->tag_set); |
35 | list_del(entry: &dev->list); |
36 | kfree(objp: dev); |
37 | } |
38 | |
39 | static void blktrans_dev_put(struct mtd_blktrans_dev *dev) |
40 | { |
41 | kref_put(kref: &dev->ref, release: blktrans_dev_release); |
42 | } |
43 | |
44 | |
45 | static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr, |
46 | struct mtd_blktrans_dev *dev, |
47 | struct request *req) |
48 | { |
49 | struct req_iterator iter; |
50 | struct bio_vec bvec; |
51 | unsigned long block, nsect; |
52 | char *buf; |
53 | |
54 | block = blk_rq_pos(rq: req) << 9 >> tr->blkshift; |
55 | nsect = blk_rq_cur_bytes(rq: req) >> tr->blkshift; |
56 | |
57 | switch (req_op(req)) { |
58 | case REQ_OP_FLUSH: |
59 | if (tr->flush(dev)) |
60 | return BLK_STS_IOERR; |
61 | return BLK_STS_OK; |
62 | case REQ_OP_DISCARD: |
63 | if (tr->discard(dev, block, nsect)) |
64 | return BLK_STS_IOERR; |
65 | return BLK_STS_OK; |
66 | case REQ_OP_READ: |
67 | buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); |
68 | for (; nsect > 0; nsect--, block++, buf += tr->blksize) { |
69 | if (tr->readsect(dev, block, buf)) { |
70 | kunmap(bio_page(req->bio)); |
71 | return BLK_STS_IOERR; |
72 | } |
73 | } |
74 | kunmap(bio_page(req->bio)); |
75 | |
76 | rq_for_each_segment(bvec, req, iter) |
77 | flush_dcache_page(page: bvec.bv_page); |
78 | return BLK_STS_OK; |
79 | case REQ_OP_WRITE: |
80 | if (!tr->writesect) |
81 | return BLK_STS_IOERR; |
82 | |
83 | rq_for_each_segment(bvec, req, iter) |
84 | flush_dcache_page(page: bvec.bv_page); |
85 | |
86 | buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); |
87 | for (; nsect > 0; nsect--, block++, buf += tr->blksize) { |
88 | if (tr->writesect(dev, block, buf)) { |
89 | kunmap(bio_page(req->bio)); |
90 | return BLK_STS_IOERR; |
91 | } |
92 | } |
93 | kunmap(bio_page(req->bio)); |
94 | return BLK_STS_OK; |
95 | default: |
96 | return BLK_STS_IOERR; |
97 | } |
98 | } |
99 | |
100 | int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) |
101 | { |
102 | return dev->bg_stop; |
103 | } |
104 | EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); |
105 | |
106 | static struct request *mtd_next_request(struct mtd_blktrans_dev *dev) |
107 | { |
108 | struct request *rq; |
109 | |
110 | rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist); |
111 | if (rq) { |
112 | list_del_init(entry: &rq->queuelist); |
113 | blk_mq_start_request(rq); |
114 | return rq; |
115 | } |
116 | |
117 | return NULL; |
118 | } |
119 | |
120 | static void mtd_blktrans_work(struct mtd_blktrans_dev *dev) |
121 | __releases(&dev->queue_lock) |
122 | __acquires(&dev->queue_lock) |
123 | { |
124 | struct mtd_blktrans_ops *tr = dev->tr; |
125 | struct request *req = NULL; |
126 | int background_done = 0; |
127 | |
128 | while (1) { |
129 | blk_status_t res; |
130 | |
131 | dev->bg_stop = false; |
132 | if (!req && !(req = mtd_next_request(dev))) { |
133 | if (tr->background && !background_done) { |
134 | spin_unlock_irq(lock: &dev->queue_lock); |
135 | mutex_lock(&dev->lock); |
136 | tr->background(dev); |
137 | mutex_unlock(lock: &dev->lock); |
138 | spin_lock_irq(lock: &dev->queue_lock); |
139 | /* |
140 | * Do background processing just once per idle |
141 | * period. |
142 | */ |
143 | background_done = !dev->bg_stop; |
144 | continue; |
145 | } |
146 | break; |
147 | } |
148 | |
149 | spin_unlock_irq(lock: &dev->queue_lock); |
150 | |
151 | mutex_lock(&dev->lock); |
152 | res = do_blktrans_request(tr: dev->tr, dev, req); |
153 | mutex_unlock(lock: &dev->lock); |
154 | |
155 | if (!blk_update_request(rq: req, error: res, nr_bytes: blk_rq_cur_bytes(rq: req))) { |
156 | __blk_mq_end_request(rq: req, error: res); |
157 | req = NULL; |
158 | } |
159 | |
160 | background_done = 0; |
161 | cond_resched(); |
162 | spin_lock_irq(lock: &dev->queue_lock); |
163 | } |
164 | } |
165 | |
166 | static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx, |
167 | const struct blk_mq_queue_data *bd) |
168 | { |
169 | struct mtd_blktrans_dev *dev; |
170 | |
171 | dev = hctx->queue->queuedata; |
172 | if (!dev) { |
173 | blk_mq_start_request(rq: bd->rq); |
174 | return BLK_STS_IOERR; |
175 | } |
176 | |
177 | spin_lock_irq(lock: &dev->queue_lock); |
178 | list_add_tail(new: &bd->rq->queuelist, head: &dev->rq_list); |
179 | mtd_blktrans_work(dev); |
180 | spin_unlock_irq(lock: &dev->queue_lock); |
181 | |
182 | return BLK_STS_OK; |
183 | } |
184 | |
185 | static int blktrans_open(struct gendisk *disk, blk_mode_t mode) |
186 | { |
187 | struct mtd_blktrans_dev *dev = disk->private_data; |
188 | int ret = 0; |
189 | |
190 | kref_get(kref: &dev->ref); |
191 | |
192 | mutex_lock(&dev->lock); |
193 | |
194 | if (dev->open) |
195 | goto unlock; |
196 | |
197 | __module_get(module: dev->tr->owner); |
198 | |
199 | if (!dev->mtd) |
200 | goto unlock; |
201 | |
202 | if (dev->tr->open) { |
203 | ret = dev->tr->open(dev); |
204 | if (ret) |
205 | goto error_put; |
206 | } |
207 | |
208 | ret = __get_mtd_device(mtd: dev->mtd); |
209 | if (ret) |
210 | goto error_release; |
211 | dev->writable = mode & BLK_OPEN_WRITE; |
212 | |
213 | unlock: |
214 | dev->open++; |
215 | mutex_unlock(lock: &dev->lock); |
216 | return ret; |
217 | |
218 | error_release: |
219 | if (dev->tr->release) |
220 | dev->tr->release(dev); |
221 | error_put: |
222 | module_put(module: dev->tr->owner); |
223 | mutex_unlock(lock: &dev->lock); |
224 | blktrans_dev_put(dev); |
225 | return ret; |
226 | } |
227 | |
228 | static void blktrans_release(struct gendisk *disk) |
229 | { |
230 | struct mtd_blktrans_dev *dev = disk->private_data; |
231 | |
232 | mutex_lock(&dev->lock); |
233 | |
234 | if (--dev->open) |
235 | goto unlock; |
236 | |
237 | module_put(module: dev->tr->owner); |
238 | |
239 | if (dev->mtd) { |
240 | if (dev->tr->release) |
241 | dev->tr->release(dev); |
242 | __put_mtd_device(mtd: dev->mtd); |
243 | } |
244 | unlock: |
245 | mutex_unlock(lock: &dev->lock); |
246 | blktrans_dev_put(dev); |
247 | } |
248 | |
249 | static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) |
250 | { |
251 | struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data; |
252 | int ret = -ENXIO; |
253 | |
254 | mutex_lock(&dev->lock); |
255 | |
256 | if (!dev->mtd) |
257 | goto unlock; |
258 | |
259 | ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY; |
260 | unlock: |
261 | mutex_unlock(lock: &dev->lock); |
262 | return ret; |
263 | } |
264 | |
265 | static const struct block_device_operations mtd_block_ops = { |
266 | .owner = THIS_MODULE, |
267 | .open = blktrans_open, |
268 | .release = blktrans_release, |
269 | .getgeo = blktrans_getgeo, |
270 | }; |
271 | |
272 | static const struct blk_mq_ops mtd_mq_ops = { |
273 | .queue_rq = mtd_queue_rq, |
274 | }; |
275 | |
276 | int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) |
277 | { |
278 | struct mtd_blktrans_ops *tr = new->tr; |
279 | struct mtd_blktrans_dev *d; |
280 | struct queue_limits lim = { }; |
281 | int last_devnum = -1; |
282 | struct gendisk *gd; |
283 | int ret; |
284 | |
285 | lockdep_assert_held(&mtd_table_mutex); |
286 | |
287 | list_for_each_entry(d, &tr->devs, list) { |
288 | if (new->devnum == -1) { |
289 | /* Use first free number */ |
290 | if (d->devnum != last_devnum+1) { |
291 | /* Found a free devnum. Plug it in here */ |
292 | new->devnum = last_devnum+1; |
293 | list_add_tail(new: &new->list, head: &d->list); |
294 | goto added; |
295 | } |
296 | } else if (d->devnum == new->devnum) { |
297 | /* Required number taken */ |
298 | return -EBUSY; |
299 | } else if (d->devnum > new->devnum) { |
300 | /* Required number was free */ |
301 | list_add_tail(new: &new->list, head: &d->list); |
302 | goto added; |
303 | } |
304 | last_devnum = d->devnum; |
305 | } |
306 | |
307 | ret = -EBUSY; |
308 | if (new->devnum == -1) |
309 | new->devnum = last_devnum+1; |
310 | |
311 | /* Check that the device and any partitions will get valid |
312 | * minor numbers and that the disk naming code below can cope |
313 | * with this number. */ |
314 | if (new->devnum > (MINORMASK >> tr->part_bits) || |
315 | (tr->part_bits && new->devnum >= 27 * 26)) |
316 | return ret; |
317 | |
318 | list_add_tail(new: &new->list, head: &tr->devs); |
319 | added: |
320 | |
321 | mutex_init(&new->lock); |
322 | kref_init(kref: &new->ref); |
323 | if (!tr->writesect) |
324 | new->readonly = 1; |
325 | |
326 | ret = -ENOMEM; |
327 | new->tag_set = kzalloc(size: sizeof(*new->tag_set), GFP_KERNEL); |
328 | if (!new->tag_set) |
329 | goto out_list_del; |
330 | |
331 | ret = blk_mq_alloc_sq_tag_set(set: new->tag_set, ops: &mtd_mq_ops, queue_depth: 2, |
332 | set_flags: BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING); |
333 | if (ret) |
334 | goto out_kfree_tag_set; |
335 | |
336 | lim.logical_block_size = tr->blksize; |
337 | if (tr->discard) |
338 | lim.max_hw_discard_sectors = UINT_MAX; |
339 | |
340 | /* Create gendisk */ |
341 | gd = blk_mq_alloc_disk(new->tag_set, &lim, new); |
342 | if (IS_ERR(ptr: gd)) { |
343 | ret = PTR_ERR(ptr: gd); |
344 | goto out_free_tag_set; |
345 | } |
346 | |
347 | new->disk = gd; |
348 | new->rq = new->disk->queue; |
349 | gd->private_data = new; |
350 | gd->major = tr->major; |
351 | gd->first_minor = (new->devnum) << tr->part_bits; |
352 | gd->minors = 1 << tr->part_bits; |
353 | gd->fops = &mtd_block_ops; |
354 | |
355 | if (tr->part_bits) { |
356 | if (new->devnum < 26) |
357 | snprintf(buf: gd->disk_name, size: sizeof(gd->disk_name), |
358 | fmt: "%s%c" , tr->name, 'a' + new->devnum); |
359 | else |
360 | snprintf(buf: gd->disk_name, size: sizeof(gd->disk_name), |
361 | fmt: "%s%c%c" , tr->name, |
362 | 'a' - 1 + new->devnum / 26, |
363 | 'a' + new->devnum % 26); |
364 | } else { |
365 | snprintf(buf: gd->disk_name, size: sizeof(gd->disk_name), |
366 | fmt: "%s%d" , tr->name, new->devnum); |
367 | gd->flags |= GENHD_FL_NO_PART; |
368 | } |
369 | |
370 | set_capacity(disk: gd, size: ((u64)new->size * tr->blksize) >> 9); |
371 | |
372 | /* Create the request queue */ |
373 | spin_lock_init(&new->queue_lock); |
374 | INIT_LIST_HEAD(list: &new->rq_list); |
375 | |
376 | if (tr->flush) |
377 | blk_queue_write_cache(q: new->rq, enabled: true, fua: false); |
378 | |
379 | blk_queue_flag_set(QUEUE_FLAG_NONROT, q: new->rq); |
380 | blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q: new->rq); |
381 | |
382 | gd->queue = new->rq; |
383 | |
384 | if (new->readonly) |
385 | set_disk_ro(disk: gd, read_only: 1); |
386 | |
387 | ret = device_add_disk(parent: &new->mtd->dev, disk: gd, NULL); |
388 | if (ret) |
389 | goto out_cleanup_disk; |
390 | |
391 | if (new->disk_attributes) { |
392 | ret = sysfs_create_group(kobj: &disk_to_dev(gd)->kobj, |
393 | grp: new->disk_attributes); |
394 | WARN_ON(ret); |
395 | } |
396 | return 0; |
397 | |
398 | out_cleanup_disk: |
399 | put_disk(disk: new->disk); |
400 | out_free_tag_set: |
401 | blk_mq_free_tag_set(set: new->tag_set); |
402 | out_kfree_tag_set: |
403 | kfree(objp: new->tag_set); |
404 | out_list_del: |
405 | list_del(entry: &new->list); |
406 | return ret; |
407 | } |
408 | |
409 | int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) |
410 | { |
411 | unsigned long flags; |
412 | |
413 | lockdep_assert_held(&mtd_table_mutex); |
414 | |
415 | if (old->disk_attributes) |
416 | sysfs_remove_group(kobj: &disk_to_dev(old->disk)->kobj, |
417 | grp: old->disk_attributes); |
418 | |
419 | /* Stop new requests to arrive */ |
420 | del_gendisk(gp: old->disk); |
421 | |
422 | /* Kill current requests */ |
423 | spin_lock_irqsave(&old->queue_lock, flags); |
424 | old->rq->queuedata = NULL; |
425 | spin_unlock_irqrestore(lock: &old->queue_lock, flags); |
426 | |
427 | /* freeze+quiesce queue to ensure all requests are flushed */ |
428 | blk_mq_freeze_queue(q: old->rq); |
429 | blk_mq_quiesce_queue(q: old->rq); |
430 | blk_mq_unquiesce_queue(q: old->rq); |
431 | blk_mq_unfreeze_queue(q: old->rq); |
432 | |
433 | /* If the device is currently open, tell trans driver to close it, |
434 | then put mtd device, and don't touch it again */ |
435 | mutex_lock(&old->lock); |
436 | if (old->open) { |
437 | if (old->tr->release) |
438 | old->tr->release(old); |
439 | __put_mtd_device(mtd: old->mtd); |
440 | } |
441 | |
442 | old->mtd = NULL; |
443 | |
444 | mutex_unlock(lock: &old->lock); |
445 | blktrans_dev_put(dev: old); |
446 | return 0; |
447 | } |
448 | |
449 | static void blktrans_notify_remove(struct mtd_info *mtd) |
450 | { |
451 | struct mtd_blktrans_ops *tr; |
452 | struct mtd_blktrans_dev *dev, *next; |
453 | |
454 | list_for_each_entry(tr, &blktrans_majors, list) |
455 | list_for_each_entry_safe(dev, next, &tr->devs, list) |
456 | if (dev->mtd == mtd) |
457 | tr->remove_dev(dev); |
458 | } |
459 | |
460 | static void blktrans_notify_add(struct mtd_info *mtd) |
461 | { |
462 | struct mtd_blktrans_ops *tr; |
463 | |
464 | if (mtd->type == MTD_ABSENT || mtd->type == MTD_UBIVOLUME) |
465 | return; |
466 | |
467 | list_for_each_entry(tr, &blktrans_majors, list) |
468 | tr->add_mtd(tr, mtd); |
469 | } |
470 | |
471 | static struct mtd_notifier blktrans_notifier = { |
472 | .add = blktrans_notify_add, |
473 | .remove = blktrans_notify_remove, |
474 | }; |
475 | |
476 | int register_mtd_blktrans(struct mtd_blktrans_ops *tr) |
477 | { |
478 | struct mtd_info *mtd; |
479 | int ret; |
480 | |
481 | /* Register the notifier if/when the first device type is |
482 | registered, to prevent the link/init ordering from fucking |
483 | us over. */ |
484 | if (!blktrans_notifier.list.next) |
485 | register_mtd_user(new: &blktrans_notifier); |
486 | |
487 | ret = register_blkdev(tr->major, tr->name); |
488 | if (ret < 0) { |
489 | printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n" , |
490 | tr->name, tr->major, ret); |
491 | return ret; |
492 | } |
493 | |
494 | if (ret) |
495 | tr->major = ret; |
496 | |
497 | tr->blkshift = ffs(tr->blksize) - 1; |
498 | |
499 | INIT_LIST_HEAD(list: &tr->devs); |
500 | |
501 | mutex_lock(&mtd_table_mutex); |
502 | list_add(new: &tr->list, head: &blktrans_majors); |
503 | mtd_for_each_device(mtd) |
504 | if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME) |
505 | tr->add_mtd(tr, mtd); |
506 | mutex_unlock(lock: &mtd_table_mutex); |
507 | return 0; |
508 | } |
509 | |
510 | int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) |
511 | { |
512 | struct mtd_blktrans_dev *dev, *next; |
513 | |
514 | mutex_lock(&mtd_table_mutex); |
515 | |
516 | /* Remove it from the list of active majors */ |
517 | list_del(entry: &tr->list); |
518 | |
519 | list_for_each_entry_safe(dev, next, &tr->devs, list) |
520 | tr->remove_dev(dev); |
521 | |
522 | mutex_unlock(lock: &mtd_table_mutex); |
523 | unregister_blkdev(major: tr->major, name: tr->name); |
524 | |
525 | BUG_ON(!list_empty(&tr->devs)); |
526 | return 0; |
527 | } |
528 | |
529 | static void __exit mtd_blktrans_exit(void) |
530 | { |
531 | /* No race here -- if someone's currently in register_mtd_blktrans |
532 | we're screwed anyway. */ |
533 | if (blktrans_notifier.list.next) |
534 | unregister_mtd_user(old: &blktrans_notifier); |
535 | } |
536 | |
537 | module_exit(mtd_blktrans_exit); |
538 | |
539 | EXPORT_SYMBOL_GPL(register_mtd_blktrans); |
540 | EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); |
541 | EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); |
542 | EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); |
543 | |
544 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>" ); |
545 | MODULE_LICENSE("GPL" ); |
546 | MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'" ); |
547 | |