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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 dev->disk->private_data = NULL;
34 blk_cleanup_queue(dev->rq);
35 blk_mq_free_tag_set(dev->tag_set);
36 kfree(dev->tag_set);
37 put_disk(dev->disk);
38 list_del(&dev->list);
39 kfree(dev);
40}
41
42static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
43{
44 struct mtd_blktrans_dev *dev;
45
46 mutex_lock(&blktrans_ref_mutex);
47 dev = disk->private_data;
48
49 if (!dev)
50 goto unlock;
51 kref_get(&dev->ref);
52unlock:
53 mutex_unlock(&blktrans_ref_mutex);
54 return dev;
55}
56
57static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
58{
59 mutex_lock(&blktrans_ref_mutex);
60 kref_put(&dev->ref, blktrans_dev_release);
61 mutex_unlock(&blktrans_ref_mutex);
62}
63
64
65static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr,
66 struct mtd_blktrans_dev *dev,
67 struct request *req)
68{
69 unsigned long block, nsect;
70 char *buf;
71
72 block = blk_rq_pos(req) << 9 >> tr->blkshift;
73 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
74
75 if (req_op(req) == REQ_OP_FLUSH) {
76 if (tr->flush(dev))
77 return BLK_STS_IOERR;
78 return BLK_STS_OK;
79 }
80
81 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
82 get_capacity(req->rq_disk))
83 return BLK_STS_IOERR;
84
85 switch (req_op(req)) {
86 case REQ_OP_DISCARD:
87 if (tr->discard(dev, block, nsect))
88 return BLK_STS_IOERR;
89 return BLK_STS_OK;
90 case REQ_OP_READ:
91 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
92 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
93 if (tr->readsect(dev, block, buf)) {
94 kunmap(bio_page(req->bio));
95 return BLK_STS_IOERR;
96 }
97 }
98 kunmap(bio_page(req->bio));
99 rq_flush_dcache_pages(req);
100 return BLK_STS_OK;
101 case REQ_OP_WRITE:
102 if (!tr->writesect)
103 return BLK_STS_IOERR;
104
105 rq_flush_dcache_pages(req);
106 buf = kmap(bio_page(req->bio)) + bio_offset(req->bio);
107 for (; nsect > 0; nsect--, block++, buf += tr->blksize) {
108 if (tr->writesect(dev, block, buf)) {
109 kunmap(bio_page(req->bio));
110 return BLK_STS_IOERR;
111 }
112 }
113 kunmap(bio_page(req->bio));
114 return BLK_STS_OK;
115 default:
116 return BLK_STS_IOERR;
117 }
118}
119
120int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
121{
122 return dev->bg_stop;
123}
124EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
125
126static struct request *mtd_next_request(struct mtd_blktrans_dev *dev)
127{
128 struct request *rq;
129
130 rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist);
131 if (rq) {
132 list_del_init(&rq->queuelist);
133 blk_mq_start_request(rq);
134 return rq;
135 }
136
137 return NULL;
138}
139
140static void mtd_blktrans_work(struct mtd_blktrans_dev *dev)
141 __releases(&dev->queue_lock)
142 __acquires(&dev->queue_lock)
143{
144 struct mtd_blktrans_ops *tr = dev->tr;
145 struct request *req = NULL;
146 int background_done = 0;
147
148 while (1) {
149 blk_status_t res;
150
151 dev->bg_stop = false;
152 if (!req && !(req = mtd_next_request(dev))) {
153 if (tr->background && !background_done) {
154 spin_unlock_irq(&dev->queue_lock);
155 mutex_lock(&dev->lock);
156 tr->background(dev);
157 mutex_unlock(&dev->lock);
158 spin_lock_irq(&dev->queue_lock);
159 /*
160 * Do background processing just once per idle
161 * period.
162 */
163 background_done = !dev->bg_stop;
164 continue;
165 }
166 break;
167 }
168
169 spin_unlock_irq(&dev->queue_lock);
170
171 mutex_lock(&dev->lock);
172 res = do_blktrans_request(dev->tr, dev, req);
173 mutex_unlock(&dev->lock);
174
175 if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) {
176 __blk_mq_end_request(req, res);
177 req = NULL;
178 }
179
180 background_done = 0;
181 spin_lock_irq(&dev->queue_lock);
182 }
183}
184
185static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
186 const struct blk_mq_queue_data *bd)
187{
188 struct mtd_blktrans_dev *dev;
189
190 dev = hctx->queue->queuedata;
191 if (!dev) {
192 blk_mq_start_request(bd->rq);
193 return BLK_STS_IOERR;
194 }
195
196 spin_lock_irq(&dev->queue_lock);
197 list_add_tail(&bd->rq->queuelist, &dev->rq_list);
198 mtd_blktrans_work(dev);
199 spin_unlock_irq(&dev->queue_lock);
200
201 return BLK_STS_OK;
202}
203
204static int blktrans_open(struct block_device *bdev, fmode_t mode)
205{
206 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
207 int ret = 0;
208
209 if (!dev)
210 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
211
212 mutex_lock(&mtd_table_mutex);
213 mutex_lock(&dev->lock);
214
215 if (dev->open)
216 goto unlock;
217
218 kref_get(&dev->ref);
219 __module_get(dev->tr->owner);
220
221 if (!dev->mtd)
222 goto unlock;
223
224 if (dev->tr->open) {
225 ret = dev->tr->open(dev);
226 if (ret)
227 goto error_put;
228 }
229
230 ret = __get_mtd_device(dev->mtd);
231 if (ret)
232 goto error_release;
233 dev->file_mode = mode;
234
235unlock:
236 dev->open++;
237 mutex_unlock(&dev->lock);
238 mutex_unlock(&mtd_table_mutex);
239 blktrans_dev_put(dev);
240 return ret;
241
242error_release:
243 if (dev->tr->release)
244 dev->tr->release(dev);
245error_put:
246 module_put(dev->tr->owner);
247 kref_put(&dev->ref, blktrans_dev_release);
248 mutex_unlock(&dev->lock);
249 mutex_unlock(&mtd_table_mutex);
250 blktrans_dev_put(dev);
251 return ret;
252}
253
254static void blktrans_release(struct gendisk *disk, fmode_t mode)
255{
256 struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
257
258 if (!dev)
259 return;
260
261 mutex_lock(&mtd_table_mutex);
262 mutex_lock(&dev->lock);
263
264 if (--dev->open)
265 goto unlock;
266
267 kref_put(&dev->ref, blktrans_dev_release);
268 module_put(dev->tr->owner);
269
270 if (dev->mtd) {
271 if (dev->tr->release)
272 dev->tr->release(dev);
273 __put_mtd_device(dev->mtd);
274 }
275unlock:
276 mutex_unlock(&dev->lock);
277 mutex_unlock(&mtd_table_mutex);
278 blktrans_dev_put(dev);
279}
280
281static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
282{
283 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
284 int ret = -ENXIO;
285
286 if (!dev)
287 return ret;
288
289 mutex_lock(&dev->lock);
290
291 if (!dev->mtd)
292 goto unlock;
293
294 ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
295unlock:
296 mutex_unlock(&dev->lock);
297 blktrans_dev_put(dev);
298 return ret;
299}
300
301static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
302 unsigned int cmd, unsigned long arg)
303{
304 struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
305 int ret = -ENXIO;
306
307 if (!dev)
308 return ret;
309
310 mutex_lock(&dev->lock);
311
312 if (!dev->mtd)
313 goto unlock;
314
315 switch (cmd) {
316 case BLKFLSBUF:
317 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
318 break;
319 default:
320 ret = -ENOTTY;
321 }
322unlock:
323 mutex_unlock(&dev->lock);
324 blktrans_dev_put(dev);
325 return ret;
326}
327
328static const struct block_device_operations mtd_block_ops = {
329 .owner = THIS_MODULE,
330 .open = blktrans_open,
331 .release = blktrans_release,
332 .ioctl = blktrans_ioctl,
333 .getgeo = blktrans_getgeo,
334};
335
336static const struct blk_mq_ops mtd_mq_ops = {
337 .queue_rq = mtd_queue_rq,
338};
339
340int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
341{
342 struct mtd_blktrans_ops *tr = new->tr;
343 struct mtd_blktrans_dev *d;
344 int last_devnum = -1;
345 struct gendisk *gd;
346 int ret;
347
348 if (mutex_trylock(&mtd_table_mutex)) {
349 mutex_unlock(&mtd_table_mutex);
350 BUG();
351 }
352
353 mutex_lock(&blktrans_ref_mutex);
354 list_for_each_entry(d, &tr->devs, list) {
355 if (new->devnum == -1) {
356 /* Use first free number */
357 if (d->devnum != last_devnum+1) {
358 /* Found a free devnum. Plug it in here */
359 new->devnum = last_devnum+1;
360 list_add_tail(&new->list, &d->list);
361 goto added;
362 }
363 } else if (d->devnum == new->devnum) {
364 /* Required number taken */
365 mutex_unlock(&blktrans_ref_mutex);
366 return -EBUSY;
367 } else if (d->devnum > new->devnum) {
368 /* Required number was free */
369 list_add_tail(&new->list, &d->list);
370 goto added;
371 }
372 last_devnum = d->devnum;
373 }
374
375 ret = -EBUSY;
376 if (new->devnum == -1)
377 new->devnum = last_devnum+1;
378
379 /* Check that the device and any partitions will get valid
380 * minor numbers and that the disk naming code below can cope
381 * with this number. */
382 if (new->devnum > (MINORMASK >> tr->part_bits) ||
383 (tr->part_bits && new->devnum >= 27 * 26)) {
384 mutex_unlock(&blktrans_ref_mutex);
385 goto error1;
386 }
387
388 list_add_tail(&new->list, &tr->devs);
389 added:
390 mutex_unlock(&blktrans_ref_mutex);
391
392 mutex_init(&new->lock);
393 kref_init(&new->ref);
394 if (!tr->writesect)
395 new->readonly = 1;
396
397 /* Create gendisk */
398 ret = -ENOMEM;
399 gd = alloc_disk(1 << tr->part_bits);
400
401 if (!gd)
402 goto error2;
403
404 new->disk = gd;
405 gd->private_data = new;
406 gd->major = tr->major;
407 gd->first_minor = (new->devnum) << tr->part_bits;
408 gd->fops = &mtd_block_ops;
409
410 if (tr->part_bits)
411 if (new->devnum < 26)
412 snprintf(gd->disk_name, sizeof(gd->disk_name),
413 "%s%c", tr->name, 'a' + new->devnum);
414 else
415 snprintf(gd->disk_name, sizeof(gd->disk_name),
416 "%s%c%c", tr->name,
417 'a' - 1 + new->devnum / 26,
418 'a' + new->devnum % 26);
419 else
420 snprintf(gd->disk_name, sizeof(gd->disk_name),
421 "%s%d", tr->name, new->devnum);
422
423 set_capacity(gd, ((u64)new->size * tr->blksize) >> 9);
424
425 /* Create the request queue */
426 spin_lock_init(&new->queue_lock);
427 INIT_LIST_HEAD(&new->rq_list);
428
429 new->tag_set = kzalloc(sizeof(*new->tag_set), GFP_KERNEL);
430 if (!new->tag_set)
431 goto error3;
432
433 new->rq = blk_mq_init_sq_queue(new->tag_set, &mtd_mq_ops, 2,
434 BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING);
435 if (IS_ERR(new->rq)) {
436 ret = PTR_ERR(new->rq);
437 new->rq = NULL;
438 goto error4;
439 }
440
441 if (tr->flush)
442 blk_queue_write_cache(new->rq, true, false);
443
444 new->rq->queuedata = new;
445 blk_queue_logical_block_size(new->rq, tr->blksize);
446
447 blk_queue_flag_set(QUEUE_FLAG_NONROT, new->rq);
448 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, new->rq);
449
450 if (tr->discard) {
451 blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
452 blk_queue_max_discard_sectors(new->rq, UINT_MAX);
453 }
454
455 gd->queue = new->rq;
456
457 if (new->readonly)
458 set_disk_ro(gd, 1);
459
460 device_add_disk(&new->mtd->dev, gd, NULL);
461
462 if (new->disk_attributes) {
463 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
464 new->disk_attributes);
465 WARN_ON(ret);
466 }
467 return 0;
468error4:
469 kfree(new->tag_set);
470error3:
471 put_disk(new->disk);
472error2:
473 list_del(&new->list);
474error1:
475 return ret;
476}
477
478int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
479{
480 unsigned long flags;
481
482 if (mutex_trylock(&mtd_table_mutex)) {
483 mutex_unlock(&mtd_table_mutex);
484 BUG();
485 }
486
487 if (old->disk_attributes)
488 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
489 old->disk_attributes);
490
491 /* Stop new requests to arrive */
492 del_gendisk(old->disk);
493
494 /* Kill current requests */
495 spin_lock_irqsave(&old->queue_lock, flags);
496 old->rq->queuedata = NULL;
497 spin_unlock_irqrestore(&old->queue_lock, flags);
498
499 /* freeze+quiesce queue to ensure all requests are flushed */
500 blk_mq_freeze_queue(old->rq);
501 blk_mq_quiesce_queue(old->rq);
502 blk_mq_unquiesce_queue(old->rq);
503 blk_mq_unfreeze_queue(old->rq);
504
505 /* If the device is currently open, tell trans driver to close it,
506 then put mtd device, and don't touch it again */
507 mutex_lock(&old->lock);
508 if (old->open) {
509 if (old->tr->release)
510 old->tr->release(old);
511 __put_mtd_device(old->mtd);
512 }
513
514 old->mtd = NULL;
515
516 mutex_unlock(&old->lock);
517 blktrans_dev_put(old);
518 return 0;
519}
520
521static void blktrans_notify_remove(struct mtd_info *mtd)
522{
523 struct mtd_blktrans_ops *tr;
524 struct mtd_blktrans_dev *dev, *next;
525
526 list_for_each_entry(tr, &blktrans_majors, list)
527 list_for_each_entry_safe(dev, next, &tr->devs, list)
528 if (dev->mtd == mtd)
529 tr->remove_dev(dev);
530}
531
532static void blktrans_notify_add(struct mtd_info *mtd)
533{
534 struct mtd_blktrans_ops *tr;
535
536 if (mtd->type == MTD_ABSENT)
537 return;
538
539 list_for_each_entry(tr, &blktrans_majors, list)
540 tr->add_mtd(tr, mtd);
541}
542
543static struct mtd_notifier blktrans_notifier = {
544 .add = blktrans_notify_add,
545 .remove = blktrans_notify_remove,
546};
547
548int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
549{
550 struct mtd_info *mtd;
551 int ret;
552
553 /* Register the notifier if/when the first device type is
554 registered, to prevent the link/init ordering from fucking
555 us over. */
556 if (!blktrans_notifier.list.next)
557 register_mtd_user(&blktrans_notifier);
558
559
560 mutex_lock(&mtd_table_mutex);
561
562 ret = register_blkdev(tr->major, tr->name);
563 if (ret < 0) {
564 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
565 tr->name, tr->major, ret);
566 mutex_unlock(&mtd_table_mutex);
567 return ret;
568 }
569
570 if (ret)
571 tr->major = ret;
572
573 tr->blkshift = ffs(tr->blksize) - 1;
574
575 INIT_LIST_HEAD(&tr->devs);
576 list_add(&tr->list, &blktrans_majors);
577
578 mtd_for_each_device(mtd)
579 if (mtd->type != MTD_ABSENT)
580 tr->add_mtd(tr, mtd);
581
582 mutex_unlock(&mtd_table_mutex);
583 return 0;
584}
585
586int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
587{
588 struct mtd_blktrans_dev *dev, *next;
589
590 mutex_lock(&mtd_table_mutex);
591
592 /* Remove it from the list of active majors */
593 list_del(&tr->list);
594
595 list_for_each_entry_safe(dev, next, &tr->devs, list)
596 tr->remove_dev(dev);
597
598 unregister_blkdev(tr->major, tr->name);
599 mutex_unlock(&mtd_table_mutex);
600
601 BUG_ON(!list_empty(&tr->devs));
602 return 0;
603}
604
605static void __exit mtd_blktrans_exit(void)
606{
607 /* No race here -- if someone's currently in register_mtd_blktrans
608 we're screwed anyway. */
609 if (blktrans_notifier.list.next)
610 unregister_mtd_user(&blktrans_notifier);
611}
612
613module_exit(mtd_blktrans_exit);
614
615EXPORT_SYMBOL_GPL(register_mtd_blktrans);
616EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
617EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
618EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
619
620MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
621MODULE_LICENSE("GPL");
622MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");