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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// 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);
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 blk_cleanup_disk(dev->disk);
34 blk_mq_free_tag_set(dev->tag_set);
35 kfree(dev->tag_set);
36 list_del(&dev->list);
37 kfree(dev);
38}
39
40static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
41{
42 struct mtd_blktrans_dev *dev;
43
44 mutex_lock(&blktrans_ref_mutex);
45 dev = disk->private_data;
46
47 if (!dev)
48 goto unlock;
49 kref_get(&dev->ref);
50unlock:
51 mutex_unlock(&blktrans_ref_mutex);
52 return dev;
53}
54
55static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
56{
57 mutex_lock(&blktrans_ref_mutex);
58 kref_put(&dev->ref, blktrans_dev_release);
59 mutex_unlock(&blktrans_ref_mutex);
60}
61
62
63static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
64 struct mtd_blktrans_dev *dev,
65 struct request *req)
66{
67 unsigned long block, nsect;
68 char *buf;
69
70 block = blk_rq_pos(req) << 9 >> tr->blkshift;
71 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
72
73 if (req_op(req) == REQ_OP_FLUSH) {
74 if (tr->flush(dev))
75 return BLK_STS_IOERR;
76 return BLK_STS_OK;
77 }
78
79 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
80 get_capacity(req->rq_disk))
81 return BLK_STS_IOERR;
82
83 switch (req_op(req)) {
84 case REQ_OP_DISCARD:
85 if (tr->discard(dev, block, nsect))
86 return BLK_STS_IOERR;
87 return BLK_STS_OK;
88 case REQ_OP_READ:
89 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
90 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
91 if (tr->readsect(dev, block, buf)) {
92 kunmap(bio_page(req->bio));
93 return BLK_STS_IOERR;
94 }
95 }
96 kunmap(bio_page(req->bio));
97 rq_flush_dcache_pages(req);
98 return BLK_STS_OK;
99 case REQ_OP_WRITE:
100 if (!tr->writesect)
101 return BLK_STS_IOERR;
102
103 rq_flush_dcache_pages(req);
104 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
105 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
106 if (tr->writesect(dev, block, buf)) {
107 kunmap(bio_page(req->bio));
108 return BLK_STS_IOERR;
109 }
110 }
111 kunmap(bio_page(req->bio));
112 return BLK_STS_OK;
113 default:
114 return BLK_STS_IOERR;
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 struct request *mtd_next_request(struct mtd_blktrans_dev *dev)
125{
126 struct request *rq;
127
128 rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
129 if (rq) {
130 list_del_init(&rq->queuelist);
131 blk_mq_start_request(rq);
132 return rq;
133 }
134
135 return NULL;
136}
137
138static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
139 __releases(&dev->queue_lock)
140 __acquires(&dev->queue_lock)
141{
142 struct mtd_blktrans_ops *tr = dev->tr;
143 struct request *req = NULL;
144 int background_done = 0;
145
146 while (1) {
147 blk_status_t res;
148
149 dev->bg_stop = false;
150 if (!req && !(req = mtd_next_request(dev))) {
151 if (tr->background && !background_done) {
152 spin_unlock_irq(&dev->queue_lock);
153 mutex_lock(&dev->lock);
154 tr->background(dev);
155 mutex_unlock(&dev->lock);
156 spin_lock_irq(&dev->queue_lock);
157 /*
158 * Do background processing just once per idle
159 * period.
160 */
161 background_done = !dev->bg_stop;
162 continue;
163 }
164 break;
165 }
166
167 spin_unlock_irq(&dev->queue_lock);
168
169 mutex_lock(&dev->lock);
170 res = do_blktrans_request(dev->tr, dev, req);
171 mutex_unlock(&dev->lock);
172
173 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
174 __blk_mq_end_request(req, res);
175 req = NULL;
176 }
177
178 background_done = 0;
179 spin_lock_irq(&dev->queue_lock);
180 }
181}
182
183static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
184 const struct blk_mq_queue_data *bd)
185{
186 struct mtd_blktrans_dev *dev;
187
188 dev = hctx->queue->queuedata;
189 if (!dev) {
190 blk_mq_start_request(bd->rq);
191 return BLK_STS_IOERR;
192 }
193
194 spin_lock_irq(&dev->queue_lock);
195 list_add_tail(&bd->rq->queuelist, &dev->rq_list);
196 mtd_blktrans_work(dev);
197 spin_unlock_irq(&dev->queue_lock);
198
199 return BLK_STS_OK;
200}
201
202static int blktrans_open(struct block_device *bdev, fmode_t mode)
203{
204 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
205 int ret = 0;
206
207 if (!dev)
208 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
209
210 mutex_lock(&mtd_table_mutex);
211 mutex_lock(&dev->lock);
212
213 if (dev->open)
214 goto unlock;
215
216 kref_get(&dev->ref);
217 __module_get(dev->tr->owner);
218
219 if (!dev->mtd)
220 goto unlock;
221
222 if (dev->tr->open) {
223 ret = dev->tr->open(dev);
224 if (ret)
225 goto error_put;
226 }
227
228 ret = __get_mtd_device(dev->mtd);
229 if (ret)
230 goto error_release;
231 dev->file_mode = mode;
232
233unlock:
234 dev->open++;
235 mutex_unlock(&dev->lock);
236 mutex_unlock(&mtd_table_mutex);
237 blktrans_dev_put(dev);
238 return ret;
239
240error_release:
241 if (dev->tr->release)
242 dev->tr->release(dev);
243error_put:
244 module_put(dev->tr->owner);
245 kref_put(&dev->ref, blktrans_dev_release);
246 mutex_unlock(&dev->lock);
247 mutex_unlock(&mtd_table_mutex);
248 blktrans_dev_put(dev);
249 return ret;
250}
251
252static void blktrans_release(struct gendisk *disk, fmode_t mode)
253{
254 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
255
256 if (!dev)
257 return;
258
259 mutex_lock(&mtd_table_mutex);
260 mutex_lock(&dev->lock);
261
262 if (--dev->open)
263 goto unlock;
264
265 kref_put(&dev->ref, blktrans_dev_release);
266 module_put(dev->tr->owner);
267
268 if (dev->mtd) {
269 if (dev->tr->release)
270 dev->tr->release(dev);
271 __put_mtd_device(dev->mtd);
272 }
273unlock:
274 mutex_unlock(&dev->lock);
275 mutex_unlock(&mtd_table_mutex);
276 blktrans_dev_put(dev);
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) : -ENOTTY;
293unlock:
294 mutex_unlock(&dev->lock);
295 blktrans_dev_put(dev);
296 return ret;
297}
298
299static const struct block_device_operations mtd_block_ops = {
300 .owner = THIS_MODULE,
301 .open = blktrans_open,
302 .release = blktrans_release,
303 .getgeo = blktrans_getgeo,
304};
305
306static const struct blk_mq_ops mtd_mq_ops = {
307 .queue_rq = mtd_queue_rq,
308};
309
310int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
311{
312 struct mtd_blktrans_ops *tr = new->tr;
313 struct mtd_blktrans_dev *d;
314 int last_devnum = -1;
315 struct gendisk *gd;
316 int ret;
317
318 if (mutex_trylock(&mtd_table_mutex)) {
319 mutex_unlock(&mtd_table_mutex);
320 BUG();
321 }
322
323 mutex_lock(&blktrans_ref_mutex);
324 list_for_each_entry(d, &tr->devs, list) {
325 if (new->devnum == -1) {
326 /* Use first free number */
327 if (d->devnum != last_devnum+1) {
328 /* Found a free devnum. Plug it in here */
329 new->devnum = last_devnum+1;
330 list_add_tail(&new->list, &d->list);
331 goto added;
332 }
333 } else if (d->devnum == new->devnum) {
334 /* Required number taken */
335 mutex_unlock(&blktrans_ref_mutex);
336 return -EBUSY;
337 } else if (d->devnum > new->devnum) {
338 /* Required number was free */
339 list_add_tail(&new->list, &d->list);
340 goto added;
341 }
342 last_devnum = d->devnum;
343 }
344
345 ret = -EBUSY;
346 if (new->devnum == -1)
347 new->devnum = last_devnum+1;
348
349 /* Check that the device and any partitions will get valid
350 * minor numbers and that the disk naming code below can cope
351 * with this number. */
352 if (new->devnum > (MINORMASK >> tr->part_bits) ||
353 (tr->part_bits && new->devnum >= 27 * 26)) {
354 mutex_unlock(&blktrans_ref_mutex);
355 return ret;
356 }
357
358 list_add_tail(&new->list, &tr->devs);
359 added:
360 mutex_unlock(&blktrans_ref_mutex);
361
362 mutex_init(&new->lock);
363 kref_init(&new->ref);
364 if (!tr->writesect)
365 new->readonly = 1;
366
367 ret = -ENOMEM;
368 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
369 if (!new->tag_set)
370 goto out_list_del;
371
372 ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2,
373 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
374 if (ret)
375 goto out_kfree_tag_set;
376
377 /* Create gendisk */
378 gd = blk_mq_alloc_disk(new->tag_set, new);
379 if (IS_ERR(gd)) {
380 ret = PTR_ERR(gd);
381 goto out_free_tag_set;
382 }
383
384 new->disk = gd;
385 new->rq = new->disk->queue;
386 gd->private_data = new;
387 gd->major = tr->major;
388 gd->first_minor = (new->devnum) << tr->part_bits;
389 gd->minors = 1 << tr->part_bits;
390 gd->fops = &mtd_block_ops;
391
392 if (tr->part_bits)
393 if (new->devnum < 26)
394 snprintf(gd->disk_name, sizeof(gd->disk_name),
395 "%s%c", tr->name, 'a' + new->devnum);
396 else
397 snprintf(gd->disk_name, sizeof(gd->disk_name),
398 "%s%c%c", tr->name,
399 'a' - 1 + new->devnum / 26,
400 'a' + new->devnum % 26);
401 else
402 snprintf(gd->disk_name, sizeof(gd->disk_name),
403 "%s%d", tr->name, new->devnum);
404
405 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
406
407 /* Create the request queue */
408 spin_lock_init(&new->queue_lock);
409 INIT_LIST_HEAD(&new->rq_list);
410
411 if (tr->flush)
412 blk_queue_write_cache(new->rq, true, false);
413
414 blk_queue_logical_block_size(new->rq, tr->blksize);
415
416 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
417 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
418
419 if (tr->discard) {
420 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
421 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
422 new->rq->limits.discard_granularity = tr->blksize;
423 }
424
425 gd->queue = new->rq;
426
427 if (new->readonly)
428 set_disk_ro(gd, 1);
429
430 device_add_disk(&new->mtd->dev, gd, NULL);
431
432 if (new->disk_attributes) {
433 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
434 new->disk_attributes);
435 WARN_ON(ret);
436 }
437 return 0;
438
439out_free_tag_set:
440 blk_mq_free_tag_set(new->tag_set);
441out_kfree_tag_set:
442 kfree(new->tag_set);
443out_list_del:
444 list_del(&new->list);
445 return ret;
446}
447
448int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
449{
450 unsigned long flags;
451
452 if (mutex_trylock(&mtd_table_mutex)) {
453 mutex_unlock(&mtd_table_mutex);
454 BUG();
455 }
456
457 if (old->disk_attributes)
458 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
459 old->disk_attributes);
460
461 /* Stop new requests to arrive */
462 del_gendisk(old->disk);
463
464 /* Kill current requests */
465 spin_lock_irqsave(&old->queue_lock, flags);
466 old->rq->queuedata = NULL;
467 spin_unlock_irqrestore(&old->queue_lock, flags);
468
469 /* freeze+quiesce queue to ensure all requests are flushed */
470 blk_mq_freeze_queue(old->rq);
471 blk_mq_quiesce_queue(old->rq);
472 blk_mq_unquiesce_queue(old->rq);
473 blk_mq_unfreeze_queue(old->rq);
474
475 /* If the device is currently open, tell trans driver to close it,
476 then put mtd device, and don't touch it again */
477 mutex_lock(&old->lock);
478 if (old->open) {
479 if (old->tr->release)
480 old->tr->release(old);
481 __put_mtd_device(old->mtd);
482 }
483
484 old->mtd = NULL;
485
486 mutex_unlock(&old->lock);
487 blktrans_dev_put(old);
488 return 0;
489}
490
491static void blktrans_notify_remove(struct mtd_info *mtd)
492{
493 struct mtd_blktrans_ops *tr;
494 struct mtd_blktrans_dev *dev, *next;
495
496 list_for_each_entry(tr, &blktrans_majors, list)
497 list_for_each_entry_safe(dev, next, &tr->devs, list)
498 if (dev->mtd == mtd)
499 tr->remove_dev(dev);
500}
501
502static void blktrans_notify_add(struct mtd_info *mtd)
503{
504 struct mtd_blktrans_ops *tr;
505
506 if (mtd->type == MTD_ABSENT)
507 return;
508
509 list_for_each_entry(tr, &blktrans_majors, list)
510 tr->add_mtd(tr, mtd);
511}
512
513static struct mtd_notifier blktrans_notifier = {
514 .add = blktrans_notify_add,
515 .remove = blktrans_notify_remove,
516};
517
518int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
519{
520 struct mtd_info *mtd;
521 int ret;
522
523 /* Register the notifier if/when the first device type is
524 registered, to prevent the link/init ordering from fucking
525 us over. */
526 if (!blktrans_notifier.list.next)
527 register_mtd_user(&blktrans_notifier);
528
529 ret = register_blkdev(tr->major, tr->name);
530 if (ret < 0) {
531 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
532 tr->name, tr->major, ret);
533 return ret;
534 }
535
536 if (ret)
537 tr->major = ret;
538
539 tr->blkshift = ffs(tr->blksize) - 1;
540
541 INIT_LIST_HEAD(&tr->devs);
542
543 mutex_lock(&mtd_table_mutex);
544 list_add(&tr->list, &blktrans_majors);
545 mtd_for_each_device(mtd)
546 if (mtd->type != MTD_ABSENT)
547 tr->add_mtd(tr, mtd);
548 mutex_unlock(&mtd_table_mutex);
549 return 0;
550}
551
552int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
553{
554 struct mtd_blktrans_dev *dev, *next;
555
556 mutex_lock(&mtd_table_mutex);
557
558 /* Remove it from the list of active majors */
559 list_del(&tr->list);
560
561 list_for_each_entry_safe(dev, next, &tr->devs, list)
562 tr->remove_dev(dev);
563
564 mutex_unlock(&mtd_table_mutex);
565 unregister_blkdev(tr->major, tr->name);
566
567 BUG_ON(!list_empty(&tr->devs));
568 return 0;
569}
570
571static void __exit mtd_blktrans_exit(void)
572{
573 /* No race here -- if someone's currently in register_mtd_blktrans
574 we're screwed anyway. */
575 if (blktrans_notifier.list.next)
576 unregister_mtd_user(&blktrans_notifier);
577}
578
579module_exit(mtd_blktrans_exit);
580
581EXPORT_SYMBOL_GPL(register_mtd_blktrans);
582EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
583EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
584EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
585
586MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
587MODULE_LICENSE("GPL");
588MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");