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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 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->list, &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->list, &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->list, &tr->devs);
319 added:
320
321 mutex_init(&new->lock);
322 kref_init(&new->ref);
323 if (!tr->writesect)
324 new->readonly = 1;
325
326 ret = -ENOMEM;
327 new->tag_set = kzalloc(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(new->tag_set, &mtd_mq_ops, 2,
332 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 if (tr->flush)
340 lim.features |= BLK_FEAT_WRITE_CACHE;
341
342 /* Create gendisk */
343 gd = blk_mq_alloc_disk(new->tag_set, &lim, new);
344 if (IS_ERR(gd)) {
345 ret = PTR_ERR(gd);
346 goto out_free_tag_set;
347 }
348
349 new->disk = gd;
350 new->rq = new->disk->queue;
351 gd->private_data = new;
352 gd->major = tr->major;
353 gd->first_minor = (new->devnum) << tr->part_bits;
354 gd->minors = 1 << tr->part_bits;
355 gd->fops = &mtd_block_ops;
356
357 if (tr->part_bits) {
358 if (new->devnum < 26)
359 snprintf(gd->disk_name, sizeof(gd->disk_name),
360 "%s%c", tr->name, 'a' + new->devnum);
361 else
362 snprintf(gd->disk_name, sizeof(gd->disk_name),
363 "%s%c%c", tr->name,
364 'a' - 1 + new->devnum / 26,
365 'a' + new->devnum % 26);
366 } else {
367 snprintf(gd->disk_name, sizeof(gd->disk_name),
368 "%s%d", tr->name, new->devnum);
369 gd->flags |= GENHD_FL_NO_PART;
370 }
371
372 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
373
374 /* Create the request queue */
375 spin_lock_init(&new->queue_lock);
376 INIT_LIST_HEAD(&new->rq_list);
377 gd->queue = new->rq;
378
379 if (new->readonly)
380 set_disk_ro(gd, 1);
381
382 ret = device_add_disk(&new->mtd->dev, gd, NULL);
383 if (ret)
384 goto out_cleanup_disk;
385
386 if (new->disk_attributes) {
387 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
388 new->disk_attributes);
389 WARN_ON(ret);
390 }
391 return 0;
392
393out_cleanup_disk:
394 put_disk(new->disk);
395out_free_tag_set:
396 blk_mq_free_tag_set(new->tag_set);
397out_kfree_tag_set:
398 kfree(new->tag_set);
399out_list_del:
400 list_del(&new->list);
401 return ret;
402}
403
404int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
405{
406 unsigned long flags;
407
408 lockdep_assert_held(&mtd_table_mutex);
409
410 if (old->disk_attributes)
411 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
412 old->disk_attributes);
413
414 /* Stop new requests to arrive */
415 del_gendisk(old->disk);
416
417 /* Kill current requests */
418 spin_lock_irqsave(&old->queue_lock, flags);
419 old->rq->queuedata = NULL;
420 spin_unlock_irqrestore(&old->queue_lock, flags);
421
422 /* freeze+quiesce queue to ensure all requests are flushed */
423 blk_mq_freeze_queue(old->rq);
424 blk_mq_quiesce_queue(old->rq);
425 blk_mq_unquiesce_queue(old->rq);
426 blk_mq_unfreeze_queue(old->rq);
427
428 /* If the device is currently open, tell trans driver to close it,
429 then put mtd device, and don't touch it again */
430 mutex_lock(&old->lock);
431 if (old->open) {
432 if (old->tr->release)
433 old->tr->release(old);
434 __put_mtd_device(old->mtd);
435 }
436
437 old->mtd = NULL;
438
439 mutex_unlock(&old->lock);
440 blktrans_dev_put(old);
441 return 0;
442}
443
444static void blktrans_notify_remove(struct mtd_info *mtd)
445{
446 struct mtd_blktrans_ops *tr;
447 struct mtd_blktrans_dev *dev, *next;
448
449 list_for_each_entry(tr, &blktrans_majors, list)
450 list_for_each_entry_safe(dev, next, &tr->devs, list)
451 if (dev->mtd == mtd)
452 tr->remove_dev(dev);
453}
454
455static void blktrans_notify_add(struct mtd_info *mtd)
456{
457 struct mtd_blktrans_ops *tr;
458
459 if (mtd->type == MTD_ABSENT || mtd->type == MTD_UBIVOLUME)
460 return;
461
462 list_for_each_entry(tr, &blktrans_majors, list)
463 tr->add_mtd(tr, mtd);
464}
465
466static struct mtd_notifier blktrans_notifier = {
467 .add = blktrans_notify_add,
468 .remove = blktrans_notify_remove,
469};
470
471int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
472{
473 struct mtd_info *mtd;
474 int ret;
475
476 /* Register the notifier if/when the first device type is
477 registered, to prevent the link/init ordering from fucking
478 us over. */
479 if (!blktrans_notifier.list.next)
480 register_mtd_user(&blktrans_notifier);
481
482 ret = register_blkdev(tr->major, tr->name);
483 if (ret < 0) {
484 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
485 tr->name, tr->major, ret);
486 return ret;
487 }
488
489 if (ret)
490 tr->major = ret;
491
492 tr->blkshift = ffs(tr->blksize) - 1;
493
494 INIT_LIST_HEAD(&tr->devs);
495
496 mutex_lock(&mtd_table_mutex);
497 list_add(&tr->list, &blktrans_majors);
498 mtd_for_each_device(mtd)
499 if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME)
500 tr->add_mtd(tr, mtd);
501 mutex_unlock(&mtd_table_mutex);
502 return 0;
503}
504
505int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
506{
507 struct mtd_blktrans_dev *dev, *next;
508
509 mutex_lock(&mtd_table_mutex);
510
511 /* Remove it from the list of active majors */
512 list_del(&tr->list);
513
514 list_for_each_entry_safe(dev, next, &tr->devs, list)
515 tr->remove_dev(dev);
516
517 mutex_unlock(&mtd_table_mutex);
518 unregister_blkdev(tr->major, tr->name);
519
520 BUG_ON(!list_empty(&tr->devs));
521 return 0;
522}
523
524static void __exit mtd_blktrans_exit(void)
525{
526 /* No race here -- if someone's currently in register_mtd_blktrans
527 we're screwed anyway. */
528 if (blktrans_notifier.list.next)
529 unregister_mtd_user(&blktrans_notifier);
530}
531
532module_exit(mtd_blktrans_exit);
533
534EXPORT_SYMBOL_GPL(register_mtd_blktrans);
535EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
536EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
537EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
538
539MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
540MODULE_LICENSE("GPL");
541MODULE_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/init.h>
34#include <linux/mutex.h>
35#include <linux/kthread.h>
36#include <asm/uaccess.h>
37
38#include "mtdcore.h"
39
40static LIST_HEAD(blktrans_majors);
41static DEFINE_MUTEX(blktrans_ref_mutex);
42
43static void blktrans_dev_release(struct kref *kref)
44{
45 struct mtd_blktrans_dev *dev =
46 container_of(kref, struct mtd_blktrans_dev, ref);
47
48 dev->disk->private_data = NULL;
49 blk_cleanup_queue(dev->rq);
50 put_disk(dev->disk);
51 list_del(&dev->list);
52 kfree(dev);
53}
54
55static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
56{
57 struct mtd_blktrans_dev *dev;
58
59 mutex_lock(&blktrans_ref_mutex);
60 dev = disk->private_data;
61
62 if (!dev)
63 goto unlock;
64 kref_get(&dev->ref);
65unlock:
66 mutex_unlock(&blktrans_ref_mutex);
67 return dev;
68}
69
70static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
71{
72 mutex_lock(&blktrans_ref_mutex);
73 kref_put(&dev->ref, blktrans_dev_release);
74 mutex_unlock(&blktrans_ref_mutex);
75}
76
77
78static int do_blktrans_request(struct mtd_blktrans_ops *tr,
79 struct mtd_blktrans_dev *dev,
80 struct request *req)
81{
82 unsigned long block, nsect;
83 char *buf;
84
85 block = blk_rq_pos(req) << 9 >> tr->blkshift;
86 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
87
88 buf = req->buffer;
89
90 if (req->cmd_type != REQ_TYPE_FS)
91 return -EIO;
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->cmd_flags & REQ_DISCARD)
98 return tr->discard(dev, block, nsect);
99
100 switch(rq_data_dir(req)) {
101 case READ:
102 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
103 if (tr->readsect(dev, block, buf))
104 return -EIO;
105 rq_flush_dcache_pages(req);
106 return 0;
107 case WRITE:
108 if (!tr->writesect)
109 return -EIO;
110
111 rq_flush_dcache_pages(req);
112 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
113 if (tr->writesect(dev, block, buf))
114 return -EIO;
115 return 0;
116 default:
117 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
118 return -EIO;
119 }
120}
121
122int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
123{
124 if (kthread_should_stop())
125 return 1;
126
127 return dev->bg_stop;
128}
129EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
130
131static int mtd_blktrans_thread(void *arg)
132{
133 struct mtd_blktrans_dev *dev = arg;
134 struct mtd_blktrans_ops *tr = dev->tr;
135 struct request_queue *rq = dev->rq;
136 struct request *req = NULL;
137 int background_done = 0;
138
139 spin_lock_irq(rq->queue_lock);
140
141 while (!kthread_should_stop()) {
142 int res;
143
144 dev->bg_stop = false;
145 if (!req && !(req = blk_fetch_request(rq))) {
146 if (tr->background && !background_done) {
147 spin_unlock_irq(rq->queue_lock);
148 mutex_lock(&dev->lock);
149 tr->background(dev);
150 mutex_unlock(&dev->lock);
151 spin_lock_irq(rq->queue_lock);
152 /*
153 * Do background processing just once per idle
154 * period.
155 */
156 background_done = !dev->bg_stop;
157 continue;
158 }
159 set_current_state(TASK_INTERRUPTIBLE);
160
161 if (kthread_should_stop())
162 set_current_state(TASK_RUNNING);
163
164 spin_unlock_irq(rq->queue_lock);
165 schedule();
166 spin_lock_irq(rq->queue_lock);
167 continue;
168 }
169
170 spin_unlock_irq(rq->queue_lock);
171
172 mutex_lock(&dev->lock);
173 res = do_blktrans_request(dev->tr, dev, req);
174 mutex_unlock(&dev->lock);
175
176 spin_lock_irq(rq->queue_lock);
177
178 if (!__blk_end_request_cur(req, res))
179 req = NULL;
180
181 background_done = 0;
182 }
183
184 if (req)
185 __blk_end_request_all(req, -EIO);
186
187 spin_unlock_irq(rq->queue_lock);
188
189 return 0;
190}
191
192static void mtd_blktrans_request(struct request_queue *rq)
193{
194 struct mtd_blktrans_dev *dev;
195 struct request *req = NULL;
196
197 dev = rq->queuedata;
198
199 if (!dev)
200 while ((req = blk_fetch_request(rq)) != NULL)
201 __blk_end_request_all(req, -ENODEV);
202 else {
203 dev->bg_stop = true;
204 wake_up_process(dev->thread);
205 }
206}
207
208static int blktrans_open(struct block_device *bdev, fmode_t mode)
209{
210 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
211 int ret = 0;
212
213 if (!dev)
214 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
215
216 mutex_lock(&dev->lock);
217
218 if (dev->open++)
219 goto unlock;
220
221 kref_get(&dev->ref);
222 __module_get(dev->tr->owner);
223
224 if (!dev->mtd)
225 goto unlock;
226
227 if (dev->tr->open) {
228 ret = dev->tr->open(dev);
229 if (ret)
230 goto error_put;
231 }
232
233 ret = __get_mtd_device(dev->mtd);
234 if (ret)
235 goto error_release;
236
237unlock:
238 mutex_unlock(&dev->lock);
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 blktrans_dev_put(dev);
250 return ret;
251}
252
253static int blktrans_release(struct gendisk *disk, fmode_t mode)
254{
255 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
256 int ret = 0;
257
258 if (!dev)
259 return ret;
260
261 mutex_lock(&dev->lock);
262
263 if (--dev->open)
264 goto unlock;
265
266 kref_put(&dev->ref, blktrans_dev_release);
267 module_put(dev->tr->owner);
268
269 if (dev->mtd) {
270 ret = dev->tr->release ? dev->tr->release(dev) : 0;
271 __put_mtd_device(dev->mtd);
272 }
273unlock:
274 mutex_unlock(&dev->lock);
275 blktrans_dev_put(dev);
276 return ret;
277}
278
279static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
280{
281 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
282 int ret = -ENXIO;
283
284 if (!dev)
285 return ret;
286
287 mutex_lock(&dev->lock);
288
289 if (!dev->mtd)
290 goto unlock;
291
292 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
293unlock:
294 mutex_unlock(&dev->lock);
295 blktrans_dev_put(dev);
296 return ret;
297}
298
299static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
300 unsigned int cmd, unsigned long arg)
301{
302 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
303 int ret = -ENXIO;
304
305 if (!dev)
306 return ret;
307
308 mutex_lock(&dev->lock);
309
310 if (!dev->mtd)
311 goto unlock;
312
313 switch (cmd) {
314 case BLKFLSBUF:
315 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
316 break;
317 default:
318 ret = -ENOTTY;
319 }
320unlock:
321 mutex_unlock(&dev->lock);
322 blktrans_dev_put(dev);
323 return ret;
324}
325
326static const struct block_device_operations mtd_blktrans_ops = {
327 .owner = THIS_MODULE,
328 .open = blktrans_open,
329 .release = blktrans_release,
330 .ioctl = blktrans_ioctl,
331 .getgeo = blktrans_getgeo,
332};
333
334int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
335{
336 struct mtd_blktrans_ops *tr = new->tr;
337 struct mtd_blktrans_dev *d;
338 int last_devnum = -1;
339 struct gendisk *gd;
340 int ret;
341
342 if (mutex_trylock(&mtd_table_mutex)) {
343 mutex_unlock(&mtd_table_mutex);
344 BUG();
345 }
346
347 mutex_lock(&blktrans_ref_mutex);
348 list_for_each_entry(d, &tr->devs, list) {
349 if (new->devnum == -1) {
350 /* Use first free number */
351 if (d->devnum != last_devnum+1) {
352 /* Found a free devnum. Plug it in here */
353 new->devnum = last_devnum+1;
354 list_add_tail(&new->list, &d->list);
355 goto added;
356 }
357 } else if (d->devnum == new->devnum) {
358 /* Required number taken */
359 mutex_unlock(&blktrans_ref_mutex);
360 return -EBUSY;
361 } else if (d->devnum > new->devnum) {
362 /* Required number was free */
363 list_add_tail(&new->list, &d->list);
364 goto added;
365 }
366 last_devnum = d->devnum;
367 }
368
369 ret = -EBUSY;
370 if (new->devnum == -1)
371 new->devnum = last_devnum+1;
372
373 /* Check that the device and any partitions will get valid
374 * minor numbers and that the disk naming code below can cope
375 * with this number. */
376 if (new->devnum > (MINORMASK >> tr->part_bits) ||
377 (tr->part_bits && new->devnum >= 27 * 26)) {
378 mutex_unlock(&blktrans_ref_mutex);
379 goto error1;
380 }
381
382 list_add_tail(&new->list, &tr->devs);
383 added:
384 mutex_unlock(&blktrans_ref_mutex);
385
386 mutex_init(&new->lock);
387 kref_init(&new->ref);
388 if (!tr->writesect)
389 new->readonly = 1;
390
391 /* Create gendisk */
392 ret = -ENOMEM;
393 gd = alloc_disk(1 << tr->part_bits);
394
395 if (!gd)
396 goto error2;
397
398 new->disk = gd;
399 gd->private_data = new;
400 gd->major = tr->major;
401 gd->first_minor = (new->devnum) << tr->part_bits;
402 gd->fops = &mtd_blktrans_ops;
403
404 if (tr->part_bits)
405 if (new->devnum < 26)
406 snprintf(gd->disk_name, sizeof(gd->disk_name),
407 "%s%c", tr->name, 'a' + new->devnum);
408 else
409 snprintf(gd->disk_name, sizeof(gd->disk_name),
410 "%s%c%c", tr->name,
411 'a' - 1 + new->devnum / 26,
412 'a' + new->devnum % 26);
413 else
414 snprintf(gd->disk_name, sizeof(gd->disk_name),
415 "%s%d", tr->name, new->devnum);
416
417 set_capacity(gd, (new->size * tr->blksize) >> 9);
418
419 /* Create the request queue */
420 spin_lock_init(&new->queue_lock);
421 new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
422
423 if (!new->rq)
424 goto error3;
425
426 new->rq->queuedata = new;
427 blk_queue_logical_block_size(new->rq, tr->blksize);
428
429 if (tr->discard) {
430 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
431 new->rq->limits.max_discard_sectors = UINT_MAX;
432 }
433
434 gd->queue = new->rq;
435
436 /* Create processing thread */
437 /* TODO: workqueue ? */
438 new->thread = kthread_run(mtd_blktrans_thread, new,
439 "%s%d", tr->name, new->mtd->index);
440 if (IS_ERR(new->thread)) {
441 ret = PTR_ERR(new->thread);
442 goto error4;
443 }
444 gd->driverfs_dev = &new->mtd->dev;
445
446 if (new->readonly)
447 set_disk_ro(gd, 1);
448
449 add_disk(gd);
450
451 if (new->disk_attributes) {
452 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
453 new->disk_attributes);
454 WARN_ON(ret);
455 }
456 return 0;
457error4:
458 blk_cleanup_queue(new->rq);
459error3:
460 put_disk(new->disk);
461error2:
462 list_del(&new->list);
463error1:
464 return ret;
465}
466
467int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
468{
469 unsigned long flags;
470
471 if (mutex_trylock(&mtd_table_mutex)) {
472 mutex_unlock(&mtd_table_mutex);
473 BUG();
474 }
475
476 if (old->disk_attributes)
477 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
478 old->disk_attributes);
479
480 /* Stop new requests to arrive */
481 del_gendisk(old->disk);
482
483
484 /* Stop the thread */
485 kthread_stop(old->thread);
486
487 /* Kill current requests */
488 spin_lock_irqsave(&old->queue_lock, flags);
489 old->rq->queuedata = NULL;
490 blk_start_queue(old->rq);
491 spin_unlock_irqrestore(&old->queue_lock, flags);
492
493 /* If the device is currently open, tell trans driver to close it,
494 then put mtd device, and don't touch it again */
495 mutex_lock(&old->lock);
496 if (old->open) {
497 if (old->tr->release)
498 old->tr->release(old);
499 __put_mtd_device(old->mtd);
500 }
501
502 old->mtd = NULL;
503
504 mutex_unlock(&old->lock);
505 blktrans_dev_put(old);
506 return 0;
507}
508
509static void blktrans_notify_remove(struct mtd_info *mtd)
510{
511 struct mtd_blktrans_ops *tr;
512 struct mtd_blktrans_dev *dev, *next;
513
514 list_for_each_entry(tr, &blktrans_majors, list)
515 list_for_each_entry_safe(dev, next, &tr->devs, list)
516 if (dev->mtd == mtd)
517 tr->remove_dev(dev);
518}
519
520static void blktrans_notify_add(struct mtd_info *mtd)
521{
522 struct mtd_blktrans_ops *tr;
523
524 if (mtd->type == MTD_ABSENT)
525 return;
526
527 list_for_each_entry(tr, &blktrans_majors, list)
528 tr->add_mtd(tr, mtd);
529}
530
531static struct mtd_notifier blktrans_notifier = {
532 .add = blktrans_notify_add,
533 .remove = blktrans_notify_remove,
534};
535
536int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
537{
538 struct mtd_info *mtd;
539 int ret;
540
541 /* Register the notifier if/when the first device type is
542 registered, to prevent the link/init ordering from fucking
543 us over. */
544 if (!blktrans_notifier.list.next)
545 register_mtd_user(&blktrans_notifier);
546
547
548 mutex_lock(&mtd_table_mutex);
549
550 ret = register_blkdev(tr->major, tr->name);
551 if (ret < 0) {
552 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
553 tr->name, tr->major, ret);
554 mutex_unlock(&mtd_table_mutex);
555 return ret;
556 }
557
558 if (ret)
559 tr->major = ret;
560
561 tr->blkshift = ffs(tr->blksize) - 1;
562
563 INIT_LIST_HEAD(&tr->devs);
564 list_add(&tr->list, &blktrans_majors);
565
566 mtd_for_each_device(mtd)
567 if (mtd->type != MTD_ABSENT)
568 tr->add_mtd(tr, mtd);
569
570 mutex_unlock(&mtd_table_mutex);
571 return 0;
572}
573
574int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
575{
576 struct mtd_blktrans_dev *dev, *next;
577
578 mutex_lock(&mtd_table_mutex);
579
580 /* Remove it from the list of active majors */
581 list_del(&tr->list);
582
583 list_for_each_entry_safe(dev, next, &tr->devs, list)
584 tr->remove_dev(dev);
585
586 unregister_blkdev(tr->major, tr->name);
587 mutex_unlock(&mtd_table_mutex);
588
589 BUG_ON(!list_empty(&tr->devs));
590 return 0;
591}
592
593static void __exit mtd_blktrans_exit(void)
594{
595 /* No race here -- if someone's currently in register_mtd_blktrans
596 we're screwed anyway. */
597 if (blktrans_notifier.list.next)
598 unregister_mtd_user(&blktrans_notifier);
599}
600
601module_exit(mtd_blktrans_exit);
602
603EXPORT_SYMBOL_GPL(register_mtd_blktrans);
604EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
605EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
606EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
607
608MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
609MODULE_LICENSE("GPL");
610MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");