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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
25static LIST_HEAD(blktrans_majors);
26static DEFINE_MUTEX(blktrans_ref_mutex);
27
28static void blktrans_dev_release(struct kref *kref)
29{
30 struct mtd_blktrans_dev *dev =
31 container_of(kref, struct mtd_blktrans_dev, ref);
32
33 dev->disk->private_data = NULL;
34 blk_cleanup_queue(dev->rq);
35 blk_mq_free_tag_set(dev->tag_set);
36 kfree(dev->tag_set);
37 put_disk(dev->disk);
38 list_del(&dev->list);
39 kfree(dev);
40}
41
42static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
43{
44 struct mtd_blktrans_dev *dev;
45
46 mutex_lock(&blktrans_ref_mutex);
47 dev = disk->private_data;
48
49 if (!dev)
50 goto unlock;
51 kref_get(&dev->ref);
52unlock:
53 mutex_unlock(&blktrans_ref_mutex);
54 return dev;
55}
56
57static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
58{
59 mutex_lock(&blktrans_ref_mutex);
60 kref_put(&dev->ref, blktrans_dev_release);
61 mutex_unlock(&blktrans_ref_mutex);
62}
63
64
65static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
66 struct mtd_blktrans_dev *dev,
67 struct request *req)
68{
69 unsigned long block, nsect;
70 char *buf;
71
72 block = blk_rq_pos(req) << 9 >> tr->blkshift;
73 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
74
75 if (req_op(req) == REQ_OP_FLUSH) {
76 if (tr->flush(dev))
77 return BLK_STS_IOERR;
78 return BLK_STS_OK;
79 }
80
81 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
82 get_capacity(req->rq_disk))
83 return BLK_STS_IOERR;
84
85 switch (req_op(req)) {
86 case REQ_OP_DISCARD:
87 if (tr->discard(dev, block, nsect))
88 return BLK_STS_IOERR;
89 return BLK_STS_OK;
90 case REQ_OP_READ:
91 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
92 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
93 if (tr->readsect(dev, block, buf)) {
94 kunmap(bio_page(req->bio));
95 return BLK_STS_IOERR;
96 }
97 }
98 kunmap(bio_page(req->bio));
99 rq_flush_dcache_pages(req);
100 return BLK_STS_OK;
101 case REQ_OP_WRITE:
102 if (!tr->writesect)
103 return BLK_STS_IOERR;
104
105 rq_flush_dcache_pages(req);
106 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
107 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
108 if (tr->writesect(dev, block, buf)) {
109 kunmap(bio_page(req->bio));
110 return BLK_STS_IOERR;
111 }
112 }
113 kunmap(bio_page(req->bio));
114 return BLK_STS_OK;
115 default:
116 return BLK_STS_IOERR;
117 }
118}
119
120int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
121{
122 return dev->bg_stop;
123}
124EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
125
126static struct request *mtd_next_request(struct mtd_blktrans_dev *dev)
127{
128 struct request *rq;
129
130 rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
131 if (rq) {
132 list_del_init(&rq->queuelist);
133 blk_mq_start_request(rq);
134 return rq;
135 }
136
137 return NULL;
138}
139
140static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
141 __releases(&dev->queue_lock)
142 __acquires(&dev->queue_lock)
143{
144 struct mtd_blktrans_ops *tr = dev->tr;
145 struct request *req = NULL;
146 int background_done = 0;
147
148 while (1) {
149 blk_status_t res;
150
151 dev->bg_stop = false;
152 if (!req && !(req = mtd_next_request(dev))) {
153 if (tr->background && !background_done) {
154 spin_unlock_irq(&dev->queue_lock);
155 mutex_lock(&dev->lock);
156 tr->background(dev);
157 mutex_unlock(&dev->lock);
158 spin_lock_irq(&dev->queue_lock);
159
160
161
162
163 background_done = !dev->bg_stop;
164 continue;
165 }
166 break;
167 }
168
169 spin_unlock_irq(&dev->queue_lock);
170
171 mutex_lock(&dev->lock);
172 res = do_blktrans_request(dev->tr, dev, req);
173 mutex_unlock(&dev->lock);
174
175 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
176 __blk_mq_end_request(req, res);
177 req = NULL;
178 }
179
180 background_done = 0;
181 spin_lock_irq(&dev->queue_lock);
182 }
183}
184
185static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
186 const struct blk_mq_queue_data *bd)
187{
188 struct mtd_blktrans_dev *dev;
189
190 dev = hctx->queue->queuedata;
191 if (!dev) {
192 blk_mq_start_request(bd->rq);
193 return BLK_STS_IOERR;
194 }
195
196 spin_lock_irq(&dev->queue_lock);
197 list_add_tail(&bd->rq->queuelist, &dev->rq_list);
198 mtd_blktrans_work(dev);
199 spin_unlock_irq(&dev->queue_lock);
200
201 return BLK_STS_OK;
202}
203
204static int blktrans_open(struct block_device *bdev, fmode_t mode)
205{
206 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
207 int ret = 0;
208
209 if (!dev)
210 return -ERESTARTSYS;
211
212 mutex_lock(&mtd_table_mutex);
213 mutex_lock(&dev->lock);
214
215 if (dev->open)
216 goto unlock;
217
218 kref_get(&dev->ref);
219 __module_get(dev->tr->owner);
220
221 if (!dev->mtd)
222 goto unlock;
223
224 if (dev->tr->open) {
225 ret = dev->tr->open(dev);
226 if (ret)
227 goto error_put;
228 }
229
230 ret = __get_mtd_device(dev->mtd);
231 if (ret)
232 goto error_release;
233 dev->file_mode = mode;
234
235unlock:
236 dev->open++;
237 mutex_unlock(&dev->lock);
238 mutex_unlock(&mtd_table_mutex);
239 blktrans_dev_put(dev);
240 return ret;
241
242error_release:
243 if (dev->tr->release)
244 dev->tr->release(dev);
245error_put:
246 module_put(dev->tr->owner);
247 kref_put(&dev->ref, blktrans_dev_release);
248 mutex_unlock(&dev->lock);
249 mutex_unlock(&mtd_table_mutex);
250 blktrans_dev_put(dev);
251 return ret;
252}
253
254static void blktrans_release(struct gendisk *disk, fmode_t mode)
255{
256 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
257
258 if (!dev)
259 return;
260
261 mutex_lock(&mtd_table_mutex);
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 if (dev->tr->release)
272 dev->tr->release(dev);
273 __put_mtd_device(dev->mtd);
274 }
275unlock:
276 mutex_unlock(&dev->lock);
277 mutex_unlock(&mtd_table_mutex);
278 blktrans_dev_put(dev);
279}
280
281static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
282{
283 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
284 int ret = -ENXIO;
285
286 if (!dev)
287 return ret;
288
289 mutex_lock(&dev->lock);
290
291 if (!dev->mtd)
292 goto unlock;
293
294 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
295unlock:
296 mutex_unlock(&dev->lock);
297 blktrans_dev_put(dev);
298 return ret;
299}
300
301static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
302 unsigned int cmd, unsigned long arg)
303{
304 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
305 int ret = -ENXIO;
306
307 if (!dev)
308 return ret;
309
310 mutex_lock(&dev->lock);
311
312 if (!dev->mtd)
313 goto unlock;
314
315 switch (cmd) {
316 case BLKFLSBUF:
317 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
318 break;
319 default:
320 ret = -ENOTTY;
321 }
322unlock:
323 mutex_unlock(&dev->lock);
324 blktrans_dev_put(dev);
325 return ret;
326}
327
328static const struct block_device_operations mtd_block_ops = {
329 .owner = THIS_MODULE,
330 .open = blktrans_open,
331 .release = blktrans_release,
332 .ioctl = blktrans_ioctl,
333 .getgeo = blktrans_getgeo,
334};
335
336static const struct blk_mq_ops mtd_mq_ops = {
337 .queue_rq = mtd_queue_rq,
338};
339
340int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
341{
342 struct mtd_blktrans_ops *tr = new->tr;
343 struct mtd_blktrans_dev *d;
344 int last_devnum = -1;
345 struct gendisk *gd;
346 int ret;
347
348 if (mutex_trylock(&mtd_table_mutex)) {
349 mutex_unlock(&mtd_table_mutex);
350 BUG();
351 }
352
353 mutex_lock(&blktrans_ref_mutex);
354 list_for_each_entry(d, &tr->devs, list) {
355 if (new->devnum == -1) {
356
357 if (d->devnum != last_devnum+1) {
358
359 new->devnum = last_devnum+1;
360 list_add_tail(&new->list, &d->list);
361 goto added;
362 }
363 } else if (d->devnum == new->devnum) {
364
365 mutex_unlock(&blktrans_ref_mutex);
366 return -EBUSY;
367 } else if (d->devnum > new->devnum) {
368
369 list_add_tail(&new->list, &d->list);
370 goto added;
371 }
372 last_devnum = d->devnum;
373 }
374
375 ret = -EBUSY;
376 if (new->devnum == -1)
377 new->devnum = last_devnum+1;
378
379
380
381
382 if (new->devnum > (MINORMASK >> tr->part_bits) ||
383 (tr->part_bits && new->devnum >= 27 * 26)) {
384 mutex_unlock(&blktrans_ref_mutex);
385 goto error1;
386 }
387
388 list_add_tail(&new->list, &tr->devs);
389 added:
390 mutex_unlock(&blktrans_ref_mutex);
391
392 mutex_init(&new->lock);
393 kref_init(&new->ref);
394 if (!tr->writesect)
395 new->readonly = 1;
396
397
398 ret = -ENOMEM;
399 gd = alloc_disk(1 << tr->part_bits);
400
401 if (!gd)
402 goto error2;
403
404 new->disk = gd;
405 gd->private_data = new;
406 gd->major = tr->major;
407 gd->first_minor = (new->devnum) << tr->part_bits;
408 gd->fops = &mtd_block_ops;
409
410 if (tr->part_bits)
411 if (new->devnum < 26)
412 snprintf(gd->disk_name, sizeof(gd->disk_name),
413 "%s%c", tr->name, 'a' + new->devnum);
414 else
415 snprintf(gd->disk_name, sizeof(gd->disk_name),
416 "%s%c%c", tr->name,
417 'a' - 1 + new->devnum / 26,
418 'a' + new->devnum % 26);
419 else
420 snprintf(gd->disk_name, sizeof(gd->disk_name),
421 "%s%d", tr->name, new->devnum);
422
423 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
424
425
426 spin_lock_init(&new->queue_lock);
427 INIT_LIST_HEAD(&new->rq_list);
428
429 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
430 if (!new->tag_set)
431 goto error3;
432
433 new->rq = blk_mq_init_sq_queue(new->tag_set, &mtd_mq_ops, 2,
434 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
435 if (IS_ERR(new->rq)) {
436 ret = PTR_ERR(new->rq);
437 new->rq = NULL;
438 goto error4;
439 }
440
441 if (tr->flush)
442 blk_queue_write_cache(new->rq, true, false);
443
444 new->rq->queuedata = new;
445 blk_queue_logical_block_size(new->rq, tr->blksize);
446
447 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
448 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
449
450 if (tr->discard) {
451 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
452 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
453 }
454
455 gd->queue = new->rq;
456
457 if (new->readonly)
458 set_disk_ro(gd, 1);
459
460 device_add_disk(&new->mtd->dev, gd, NULL);
461
462 if (new->disk_attributes) {
463 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
464 new->disk_attributes);
465 WARN_ON(ret);
466 }
467 return 0;
468error4:
469 kfree(new->tag_set);
470error3:
471 put_disk(new->disk);
472error2:
473 list_del(&new->list);
474error1:
475 return ret;
476}
477
478int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
479{
480 unsigned long flags;
481
482 if (mutex_trylock(&mtd_table_mutex)) {
483 mutex_unlock(&mtd_table_mutex);
484 BUG();
485 }
486
487 if (old->disk_attributes)
488 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
489 old->disk_attributes);
490
491
492 del_gendisk(old->disk);
493
494
495 spin_lock_irqsave(&old->queue_lock, flags);
496 old->rq->queuedata = NULL;
497 spin_unlock_irqrestore(&old->queue_lock, flags);
498
499
500 blk_mq_freeze_queue(old->rq);
501 blk_mq_quiesce_queue(old->rq);
502 blk_mq_unquiesce_queue(old->rq);
503 blk_mq_unfreeze_queue(old->rq);
504
505
506
507 mutex_lock(&old->lock);
508 if (old->open) {
509 if (old->tr->release)
510 old->tr->release(old);
511 __put_mtd_device(old->mtd);
512 }
513
514 old->mtd = NULL;
515
516 mutex_unlock(&old->lock);
517 blktrans_dev_put(old);
518 return 0;
519}
520
521static void blktrans_notify_remove(struct mtd_info *mtd)
522{
523 struct mtd_blktrans_ops *tr;
524 struct mtd_blktrans_dev *dev, *next;
525
526 list_for_each_entry(tr, &blktrans_majors, list)
527 list_for_each_entry_safe(dev, next, &tr->devs, list)
528 if (dev->mtd == mtd)
529 tr->remove_dev(dev);
530}
531
532static void blktrans_notify_add(struct mtd_info *mtd)
533{
534 struct mtd_blktrans_ops *tr;
535
536 if (mtd->type == MTD_ABSENT)
537 return;
538
539 list_for_each_entry(tr, &blktrans_majors, list)
540 tr->add_mtd(tr, mtd);
541}
542
543static struct mtd_notifier blktrans_notifier = {
544 .add = blktrans_notify_add,
545 .remove = blktrans_notify_remove,
546};
547
548int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
549{
550 struct mtd_info *mtd;
551 int ret;
552
553
554
555
556 if (!blktrans_notifier.list.next)
557 register_mtd_user(&blktrans_notifier);
558
559
560 mutex_lock(&mtd_table_mutex);
561
562 ret = register_blkdev(tr->major, tr->name);
563 if (ret < 0) {
564 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
565 tr->name, tr->major, ret);
566 mutex_unlock(&mtd_table_mutex);
567 return ret;
568 }
569
570 if (ret)
571 tr->major = ret;
572
573 tr->blkshift = ffs(tr->blksize) - 1;
574
575 INIT_LIST_HEAD(&tr->devs);
576 list_add(&tr->list, &blktrans_majors);
577
578 mtd_for_each_device(mtd)
579 if (mtd->type != MTD_ABSENT)
580 tr->add_mtd(tr, mtd);
581
582 mutex_unlock(&mtd_table_mutex);
583 return 0;
584}
585
586int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
587{
588 struct mtd_blktrans_dev *dev, *next;
589
590 mutex_lock(&mtd_table_mutex);
591
592
593 list_del(&tr->list);
594
595 list_for_each_entry_safe(dev, next, &tr->devs, list)
596 tr->remove_dev(dev);
597
598 unregister_blkdev(tr->major, tr->name);
599 mutex_unlock(&mtd_table_mutex);
600
601 BUG_ON(!list_empty(&tr->devs));
602 return 0;
603}
604
605static void __exit mtd_blktrans_exit(void)
606{
607
608
609 if (blktrans_notifier.list.next)
610 unregister_mtd_user(&blktrans_notifier);
611}
612
613module_exit(mtd_blktrans_exit);
614
615EXPORT_SYMBOL_GPL(register_mtd_blktrans);
616EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
617EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
618EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
619
620MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
621MODULE_LICENSE("GPL");
622MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
623
