1
2
3
4
5
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
25static LIST_HEAD(blktrans_majors);
26
27static 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 blk_cleanup_disk(dev->disk);
33 blk_mq_free_tag_set(dev->tag_set);
34 kfree(dev->tag_set);
35 list_del(&dev->list);
36 kfree(dev);
37}
38
39static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
40{
41 kref_put(&dev->ref, blktrans_dev_release);
42}
43
44
45static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
46 struct mtd_blktrans_dev *dev,
47 struct request *req)
48{
49 unsigned long block, nsect;
50 char *buf;
51
52 block = blk_rq_pos(req) << 9 >> tr->blkshift;
53 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
54
55 if (req_op(req) == REQ_OP_FLUSH) {
56 if (tr->flush(dev))
57 return BLK_STS_IOERR;
58 return BLK_STS_OK;
59 }
60
61 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
62 get_capacity(req->rq_disk))
63 return BLK_STS_IOERR;
64
65 switch (req_op(req)) {
66 case REQ_OP_DISCARD:
67 if (tr->discard(dev, block, nsect))
68 return BLK_STS_IOERR;
69 return BLK_STS_OK;
70 case REQ_OP_READ:
71 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
72 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
73 if (tr->readsect(dev, block, buf)) {
74 kunmap(bio_page(req->bio));
75 return BLK_STS_IOERR;
76 }
77 }
78 kunmap(bio_page(req->bio));
79 rq_flush_dcache_pages(req);
80 return BLK_STS_OK;
81 case REQ_OP_WRITE:
82 if (!tr->writesect)
83 return BLK_STS_IOERR;
84
85 rq_flush_dcache_pages(req);
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
100int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
101{
102 return dev->bg_stop;
103}
104EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
105
106static 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(&rq->queuelist);
113 blk_mq_start_request(rq);
114 return rq;
115 }
116
117 return NULL;
118}
119
120static 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(&dev->queue_lock);
135 mutex_lock(&dev->lock);
136 tr->background(dev);
137 mutex_unlock(&dev->lock);
138 spin_lock_irq(&dev->queue_lock);
139
140
141
142
143 background_done = !dev->bg_stop;
144 continue;
145 }
146 break;
147 }
148
149 spin_unlock_irq(&dev->queue_lock);
150
151 mutex_lock(&dev->lock);
152 res = do_blktrans_request(dev->tr, dev, req);
153 mutex_unlock(&dev->lock);
154
155 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
156 __blk_mq_end_request(req, res);
157 req = NULL;
158 }
159
160 background_done = 0;
161 spin_lock_irq(&dev->queue_lock);
162 }
163}
164
165static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
166 const struct blk_mq_queue_data *bd)
167{
168 struct mtd_blktrans_dev *dev;
169
170 dev = hctx->queue->queuedata;
171 if (!dev) {
172 blk_mq_start_request(bd->rq);
173 return BLK_STS_IOERR;
174 }
175
176 spin_lock_irq(&dev->queue_lock);
177 list_add_tail(&bd->rq->queuelist, &dev->rq_list);
178 mtd_blktrans_work(dev);
179 spin_unlock_irq(&dev->queue_lock);
180
181 return BLK_STS_OK;
182}
183
184static int blktrans_open(struct block_device *bdev, fmode_t mode)
185{
186 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
187 int ret = 0;
188
189 kref_get(&dev->ref);
190
191 mutex_lock(&dev->lock);
192
193 if (dev->open)
194 goto unlock;
195
196 __module_get(dev->tr->owner);
197
198 if (!dev->mtd)
199 goto unlock;
200
201 if (dev->tr->open) {
202 ret = dev->tr->open(dev);
203 if (ret)
204 goto error_put;
205 }
206
207 ret = __get_mtd_device(dev->mtd);
208 if (ret)
209 goto error_release;
210 dev->file_mode = mode;
211
212unlock:
213 dev->open++;
214 mutex_unlock(&dev->lock);
215 return ret;
216
217error_release:
218 if (dev->tr->release)
219 dev->tr->release(dev);
220error_put:
221 module_put(dev->tr->owner);
222 mutex_unlock(&dev->lock);
223 blktrans_dev_put(dev);
224 return ret;
225}
226
227static void blktrans_release(struct gendisk *disk, fmode_t mode)
228{
229 struct mtd_blktrans_dev *dev = disk->private_data;
230
231 mutex_lock(&dev->lock);
232
233 if (--dev->open)
234 goto unlock;
235
236 module_put(dev->tr->owner);
237
238 if (dev->mtd) {
239 if (dev->tr->release)
240 dev->tr->release(dev);
241 __put_mtd_device(dev->mtd);
242 }
243unlock:
244 mutex_unlock(&dev->lock);
245 blktrans_dev_put(dev);
246}
247
248static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
249{
250 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
251 int ret = -ENXIO;
252
253 mutex_lock(&dev->lock);
254
255 if (!dev->mtd)
256 goto unlock;
257
258 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
259unlock:
260 mutex_unlock(&dev->lock);
261 return ret;
262}
263
264static const struct block_device_operations mtd_block_ops = {
265 .owner = THIS_MODULE,
266 .open = blktrans_open,
267 .release = blktrans_release,
268 .getgeo = blktrans_getgeo,
269};
270
271static const struct blk_mq_ops mtd_mq_ops = {
272 .queue_rq = mtd_queue_rq,
273};
274
275int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
276{
277 struct mtd_blktrans_ops *tr = new->tr;
278 struct mtd_blktrans_dev *d;
279 int last_devnum = -1;
280 struct gendisk *gd;
281 int ret;
282
283 lockdep_assert_held(&mtd_table_mutex);
284
285 list_for_each_entry(d, &tr->devs, list) {
286 if (new->devnum == -1) {
287
288 if (d->devnum != last_devnum+1) {
289
290 new->devnum = last_devnum+1;
291 list_add_tail(&new->list, &d->list);
292 goto added;
293 }
294 } else if (d->devnum == new->devnum) {
295
296 return -EBUSY;
297 } else if (d->devnum > new->devnum) {
298
299 list_add_tail(&new->list, &d->list);
300 goto added;
301 }
302 last_devnum = d->devnum;
303 }
304
305 ret = -EBUSY;
306 if (new->devnum == -1)
307 new->devnum = last_devnum+1;
308
309
310
311
312 if (new->devnum > (MINORMASK >> tr->part_bits) ||
313 (tr->part_bits && new->devnum >= 27 * 26))
314 return ret;
315
316 list_add_tail(&new->list, &tr->devs);
317 added:
318
319 mutex_init(&new->lock);
320 kref_init(&new->ref);
321 if (!tr->writesect)
322 new->readonly = 1;
323
324 ret = -ENOMEM;
325 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
326 if (!new->tag_set)
327 goto out_list_del;
328
329 ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,
330 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
331 if (ret)
332 goto out_kfree_tag_set;
333
334
335 gd = blk_mq_alloc_disk(new->tag_set, new);
336 if (IS_ERR(gd)) {
337 ret = PTR_ERR(gd);
338 goto out_free_tag_set;
339 }
340
341 new->disk = gd;
342 new->rq = new->disk->queue;
343 gd->private_data = new;
344 gd->major = tr->major;
345 gd->first_minor = (new->devnum) << tr->part_bits;
346 gd->minors = 1 << tr->part_bits;
347 gd->fops = &mtd_block_ops;
348
349 if (tr->part_bits)
350 if (new->devnum < 26)
351 snprintf(gd->disk_name, sizeof(gd->disk_name),
352 "%s%c", tr->name, 'a' + new->devnum);
353 else
354 snprintf(gd->disk_name, sizeof(gd->disk_name),
355 "%s%c%c", tr->name,
356 'a' - 1 + new->devnum / 26,
357 'a' + new->devnum % 26);
358 else
359 snprintf(gd->disk_name, sizeof(gd->disk_name),
360 "%s%d", tr->name, new->devnum);
361
362 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
363
364
365 spin_lock_init(&new->queue_lock);
366 INIT_LIST_HEAD(&new->rq_list);
367
368 if (tr->flush)
369 blk_queue_write_cache(new->rq, true, false);
370
371 blk_queue_logical_block_size(new->rq, tr->blksize);
372
373 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
374 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
375
376 if (tr->discard) {
377 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
378 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
379 new->rq->limits.discard_granularity = tr->blksize;
380 }
381
382 gd->queue = new->rq;
383
384 if (new->readonly)
385 set_disk_ro(gd, 1);
386
387 device_add_disk(&new->mtd->dev, gd, NULL);
388
389 if (new->disk_attributes) {
390 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
391 new->disk_attributes);
392 WARN_ON(ret);
393 }
394 return 0;
395
396out_free_tag_set:
397 blk_mq_free_tag_set(new->tag_set);
398out_kfree_tag_set:
399 kfree(new->tag_set);
400out_list_del:
401 list_del(&new->list);
402 return ret;
403}
404
405int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
406{
407 unsigned long flags;
408
409 lockdep_assert_held(&mtd_table_mutex);
410
411 if (old->disk_attributes)
412 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
413 old->disk_attributes);
414
415
416 del_gendisk(old->disk);
417
418
419 spin_lock_irqsave(&old->queue_lock, flags);
420 old->rq->queuedata = NULL;
421 spin_unlock_irqrestore(&old->queue_lock, flags);
422
423
424 blk_mq_freeze_queue(old->rq);
425 blk_mq_quiesce_queue(old->rq);
426 blk_mq_unquiesce_queue(old->rq);
427 blk_mq_unfreeze_queue(old->rq);
428
429
430
431 mutex_lock(&old->lock);
432 if (old->open) {
433 if (old->tr->release)
434 old->tr->release(old);
435 __put_mtd_device(old->mtd);
436 }
437
438 old->mtd = NULL;
439
440 mutex_unlock(&old->lock);
441 blktrans_dev_put(old);
442 return 0;
443}
444
445static void blktrans_notify_remove(struct mtd_info *mtd)
446{
447 struct mtd_blktrans_ops *tr;
448 struct mtd_blktrans_dev *dev, *next;
449
450 list_for_each_entry(tr, &blktrans_majors, list)
451 list_for_each_entry_safe(dev, next, &tr->devs, list)
452 if (dev->mtd == mtd)
453 tr->remove_dev(dev);
454}
455
456static void blktrans_notify_add(struct mtd_info *mtd)
457{
458 struct mtd_blktrans_ops *tr;
459
460 if (mtd->type == MTD_ABSENT)
461 return;
462
463 list_for_each_entry(tr, &blktrans_majors, list)
464 tr->add_mtd(tr, mtd);
465}
466
467static struct mtd_notifier blktrans_notifier = {
468 .add = blktrans_notify_add,
469 .remove = blktrans_notify_remove,
470};
471
472int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
473{
474 struct mtd_info *mtd;
475 int ret;
476
477
478
479
480 if (!blktrans_notifier.list.next)
481 register_mtd_user(&blktrans_notifier);
482
483 ret = register_blkdev(tr->major, tr->name);
484 if (ret < 0) {
485 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
486 tr->name, tr->major, ret);
487 return ret;
488 }
489
490 if (ret)
491 tr->major = ret;
492
493 tr->blkshift = ffs(tr->blksize) - 1;
494
495 INIT_LIST_HEAD(&tr->devs);
496
497 mutex_lock(&mtd_table_mutex);
498 list_add(&tr->list, &blktrans_majors);
499 mtd_for_each_device(mtd)
500 if (mtd->type != MTD_ABSENT)
501 tr->add_mtd(tr, mtd);
502 mutex_unlock(&mtd_table_mutex);
503 return 0;
504}
505
506int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
507{
508 struct mtd_blktrans_dev *dev, *next;
509
510 mutex_lock(&mtd_table_mutex);
511
512
513 list_del(&tr->list);
514
515 list_for_each_entry_safe(dev, next, &tr->devs, list)
516 tr->remove_dev(dev);
517
518 mutex_unlock(&mtd_table_mutex);
519 unregister_blkdev(tr->major, tr->name);
520
521 BUG_ON(!list_empty(&tr->devs));
522 return 0;
523}
524
525static void __exit mtd_blktrans_exit(void)
526{
527
528
529 if (blktrans_notifier.list.next)
530 unregister_mtd_user(&blktrans_notifier);
531}
532
533module_exit(mtd_blktrans_exit);
534
535EXPORT_SYMBOL_GPL(register_mtd_blktrans);
536EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
537EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
538EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
539
540MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
541MODULE_LICENSE("GPL");
542MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
543
