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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
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 put_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 struct req_iterator iter;
50 struct bio_vec bvec;
51 unsigned long block, nsect;
52 char *buf;
53
54 block = blk_rq_pos(req) << 9 >> tr->blkshift;
55 nsect = blk_rq_cur_bytes(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(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(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
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 * 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(&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 cond_resched();
162 spin_lock_irq(&dev->queue_lock);
163 }
164}
165
166static 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(bd->rq);
174 return BLK_STS_IOERR;
175 }
176
177 spin_lock_irq(&dev->queue_lock);
178 list_add_tail(&bd->rq->queuelist, &dev->rq_list);
179 mtd_blktrans_work(dev);
180 spin_unlock_irq(&dev->queue_lock);
181
182 return BLK_STS_OK;
183}
184
185static 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(&dev->ref);
191
192 mutex_lock(&dev->lock);
193
194 if (dev->open)
195 goto unlock;
196
197 __module_get(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(dev->mtd);
209 if (ret)
210 goto error_release;
211 dev->writable = mode & BLK_OPEN_WRITE;
212
213unlock:
214 dev->open++;
215 mutex_unlock(&dev->lock);
216 return ret;
217
218error_release:
219 if (dev->tr->release)
220 dev->tr->release(dev);
221error_put:
222 module_put(dev->tr->owner);
223 mutex_unlock(&dev->lock);
224 blktrans_dev_put(dev);
225 return ret;
226}
227
228static 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(dev->tr->owner);
238
239 if (dev->mtd) {
240 if (dev->tr->release)
241 dev->tr->release(dev);
242 __put_mtd_device(dev->mtd);
243 }
244unlock:
245 mutex_unlock(&dev->lock);
246 blktrans_dev_put(dev);
247}
248
249static 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;
260unlock:
261 mutex_unlock(&dev->lock);
262 return ret;
263}
264
265static 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
272static const struct blk_mq_ops mtd_mq_ops = {
273 .queue_rq = mtd_queue_rq,
274};
275
276int 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 int last_devnum = -1;
281 struct gendisk *gd;
282 int ret;
283
284 lockdep_assert_held(&mtd_table_mutex);
285
286 list_for_each_entry(d, &tr->devs, list) {
287 if (new->devnum == -1) {
288 /* Use first free number */
289 if (d->devnum != last_devnum+1) {
290 /* Found a free devnum. Plug it in here */
291 new->devnum = last_devnum+1;
292 list_add_tail(&new->list, &d->list);
293 goto added;
294 }
295 } else if (d->devnum == new->devnum) {
296 /* Required number taken */
297 return -EBUSY;
298 } else if (d->devnum > new->devnum) {
299 /* Required number was free */
300 list_add_tail(&new->list, &d->list);
301 goto added;
302 }
303 last_devnum = d->devnum;
304 }
305
306 ret = -EBUSY;
307 if (new->devnum == -1)
308 new->devnum = last_devnum+1;
309
310 /* Check that the device and any partitions will get valid
311 * minor numbers and that the disk naming code below can cope
312 * with this number. */
313 if (new->devnum > (MINORMASK >> tr->part_bits) ||
314 (tr->part_bits && new->devnum >= 27 * 26))
315 return ret;
316
317 list_add_tail(&new->list, &tr->devs);
318 added:
319
320 mutex_init(&new->lock);
321 kref_init(&new->ref);
322 if (!tr->writesect)
323 new->readonly = 1;
324
325 ret = -ENOMEM;
326 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
327 if (!new->tag_set)
328 goto out_list_del;
329
330 ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,
331 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
332 if (ret)
333 goto out_kfree_tag_set;
334
335 /* Create gendisk */
336 gd = blk_mq_alloc_disk(new->tag_set, new);
337 if (IS_ERR(gd)) {
338 ret = PTR_ERR(gd);
339 goto out_free_tag_set;
340 }
341
342 new->disk = gd;
343 new->rq = new->disk->queue;
344 gd->private_data = new;
345 gd->major = tr->major;
346 gd->first_minor = (new->devnum) << tr->part_bits;
347 gd->minors = 1 << tr->part_bits;
348 gd->fops = &mtd_block_ops;
349
350 if (tr->part_bits) {
351 if (new->devnum < 26)
352 snprintf(gd->disk_name, sizeof(gd->disk_name),
353 "%s%c", tr->name, 'a' + new->devnum);
354 else
355 snprintf(gd->disk_name, sizeof(gd->disk_name),
356 "%s%c%c", tr->name,
357 'a' - 1 + new->devnum / 26,
358 'a' + new->devnum % 26);
359 } else {
360 snprintf(gd->disk_name, sizeof(gd->disk_name),
361 "%s%d", tr->name, new->devnum);
362 gd->flags |= GENHD_FL_NO_PART;
363 }
364
365 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
366
367 /* Create the request queue */
368 spin_lock_init(&new->queue_lock);
369 INIT_LIST_HEAD(&new->rq_list);
370
371 if (tr->flush)
372 blk_queue_write_cache(new->rq, true, false);
373
374 blk_queue_logical_block_size(new->rq, tr->blksize);
375
376 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
377 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
378
379 if (tr->discard)
380 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
381
382 gd->queue = new->rq;
383
384 if (new->readonly)
385 set_disk_ro(gd, 1);
386
387 ret = device_add_disk(&new->mtd->dev, gd, NULL);
388 if (ret)
389 goto out_cleanup_disk;
390
391 if (new->disk_attributes) {
392 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
393 new->disk_attributes);
394 WARN_ON(ret);
395 }
396 return 0;
397
398out_cleanup_disk:
399 put_disk(new->disk);
400out_free_tag_set:
401 blk_mq_free_tag_set(new->tag_set);
402out_kfree_tag_set:
403 kfree(new->tag_set);
404out_list_del:
405 list_del(&new->list);
406 return ret;
407}
408
409int 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(&disk_to_dev(old->disk)->kobj,
417 old->disk_attributes);
418
419 /* Stop new requests to arrive */
420 del_gendisk(old->disk);
421
422 /* Kill current requests */
423 spin_lock_irqsave(&old->queue_lock, flags);
424 old->rq->queuedata = NULL;
425 spin_unlock_irqrestore(&old->queue_lock, flags);
426
427 /* freeze+quiesce queue to ensure all requests are flushed */
428 blk_mq_freeze_queue(old->rq);
429 blk_mq_quiesce_queue(old->rq);
430 blk_mq_unquiesce_queue(old->rq);
431 blk_mq_unfreeze_queue(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(old->mtd);
440 }
441
442 old->mtd = NULL;
443
444 mutex_unlock(&old->lock);
445 blktrans_dev_put(old);
446 return 0;
447}
448
449static 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
460static 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
471static struct mtd_notifier blktrans_notifier = {
472 .add = blktrans_notify_add,
473 .remove = blktrans_notify_remove,
474};
475
476int 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(&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(&tr->devs);
500
501 mutex_lock(&mtd_table_mutex);
502 list_add(&tr->list, &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(&mtd_table_mutex);
507 return 0;
508}
509
510int 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(&tr->list);
518
519 list_for_each_entry_safe(dev, next, &tr->devs, list)
520 tr->remove_dev(dev);
521
522 mutex_unlock(&mtd_table_mutex);
523 unregister_blkdev(tr->major, tr->name);
524
525 BUG_ON(!list_empty(&tr->devs));
526 return 0;
527}
528
529static 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(&blktrans_notifier);
535}
536
537module_exit(mtd_blktrans_exit);
538
539EXPORT_SYMBOL_GPL(register_mtd_blktrans);
540EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
541EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
542EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
543
544MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
545MODULE_LICENSE("GPL");
546MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
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 <linux/uaccess.h>
35
36#include "mtdcore.h"
37
38static LIST_HEAD(blktrans_majors);
39static DEFINE_MUTEX(blktrans_ref_mutex);
40
41static 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
53static 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);
63unlock:
64 mutex_unlock(&blktrans_ref_mutex);
65 return dev;
66}
67
68static 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
76static 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
118int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
119{
120 return dev->bg_stop;
121}
122EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
123
124static 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
173static 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
187static 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
218unlock:
219 dev->open++;
220 mutex_unlock(&dev->lock);
221 mutex_unlock(&mtd_table_mutex);
222 blktrans_dev_put(dev);
223 return ret;
224
225error_release:
226 if (dev->tr->release)
227 dev->tr->release(dev);
228error_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
237static 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 }
258unlock:
259 mutex_unlock(&dev->lock);
260 mutex_unlock(&mtd_table_mutex);
261 blktrans_dev_put(dev);
262}
263
264static 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;
278unlock:
279 mutex_unlock(&dev->lock);
280 blktrans_dev_put(dev);
281 return ret;
282}
283
284static 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 }
305unlock:
306 mutex_unlock(&dev->lock);
307 blktrans_dev_put(dev);
308 return ret;
309}
310
311static 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
319int 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;
445error4:
446 blk_cleanup_queue(new->rq);
447error3:
448 put_disk(new->disk);
449error2:
450 list_del(&new->list);
451error1:
452 return ret;
453}
454
455int 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
496static 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
507static 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
518static struct mtd_notifier blktrans_notifier = {
519 .add = blktrans_notify_add,
520 .remove = blktrans_notify_remove,
521};
522
523int 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
561int 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
580static 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
588module_exit(mtd_blktrans_exit);
589
590EXPORT_SYMBOL_GPL(register_mtd_blktrans);
591EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
592EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
593EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
594
595MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
596MODULE_LICENSE("GPL");
597MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");