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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2014 Ezequiel Garcia
4 * Copyright (c) 2011 Free Electrons
5 *
6 * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
7 * Copyright (c) International Business Machines Corp., 2006
8 * Copyright (c) Nokia Corporation, 2007
9 * Authors: Artem Bityutskiy, Frank Haverkamp
10 */
11
12/*
13 * Read-only block devices on top of UBI volumes
14 *
15 * A simple implementation to allow a block device to be layered on top of a
16 * UBI volume. The implementation is provided by creating a static 1-to-1
17 * mapping between the block device and the UBI volume.
18 *
19 * The addressed byte is obtained from the addressed block sector, which is
20 * mapped linearly into the corresponding LEB:
21 *
22 * LEB number = addressed byte / LEB size
23 *
24 * This feature is compiled in the UBI core, and adds a 'block' parameter
25 * to allow early creation of block devices on top of UBI volumes. Runtime
26 * block creation/removal for UBI volumes is provided through two UBI ioctls:
27 * UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
28 */
29
30#include <linux/module.h>
31#include <linux/init.h>
32#include <linux/err.h>
33#include <linux/kernel.h>
34#include <linux/list.h>
35#include <linux/mutex.h>
36#include <linux/slab.h>
37#include <linux/mtd/ubi.h>
38#include <linux/blkdev.h>
39#include <linux/blk-mq.h>
40#include <linux/hdreg.h>
41#include <linux/scatterlist.h>
42#include <linux/idr.h>
43#include <asm/div64.h>
44
45#include "ubi-media.h"
46#include "ubi.h"
47
48/* Maximum number of supported devices */
49#define UBIBLOCK_MAX_DEVICES 32
50
51/* Maximum length of the 'block=' parameter */
52#define UBIBLOCK_PARAM_LEN 63
53
54/* Maximum number of comma-separated items in the 'block=' parameter */
55#define UBIBLOCK_PARAM_COUNT 2
56
57struct ubiblock_param {
58 int ubi_num;
59 int vol_id;
60 char name[UBIBLOCK_PARAM_LEN+1];
61};
62
63struct ubiblock_pdu {
64 struct ubi_sgl usgl;
65};
66
67/* Numbers of elements set in the @ubiblock_param array */
68static int ubiblock_devs __initdata;
69
70/* MTD devices specification parameters */
71static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
72
73struct ubiblock {
74 struct ubi_volume_desc *desc;
75 int ubi_num;
76 int vol_id;
77 int refcnt;
78 int leb_size;
79
80 struct gendisk *gd;
81 struct request_queue *rq;
82
83 struct mutex dev_mutex;
84 struct list_head list;
85 struct blk_mq_tag_set tag_set;
86};
87
88/* Linked list of all ubiblock instances */
89static LIST_HEAD(ubiblock_devices);
90static DEFINE_IDR(ubiblock_minor_idr);
91/* Protects ubiblock_devices and ubiblock_minor_idr */
92static DEFINE_MUTEX(devices_mutex);
93static int ubiblock_major;
94
95static int __init ubiblock_set_param(const char *val,
96 const struct kernel_param *kp)
97{
98 int i, ret;
99 size_t len;
100 struct ubiblock_param *param;
101 char buf[UBIBLOCK_PARAM_LEN];
102 char *pbuf = &buf[0];
103 char *tokens[UBIBLOCK_PARAM_COUNT];
104
105 if (!val)
106 return -EINVAL;
107
108 len = strnlen(val, UBIBLOCK_PARAM_LEN);
109 if (len == 0) {
110 pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
111 return 0;
112 }
113
114 if (len == UBIBLOCK_PARAM_LEN) {
115 pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
116 val, UBIBLOCK_PARAM_LEN);
117 return -EINVAL;
118 }
119
120 strcpy(buf, val);
121
122 /* Get rid of the final newline */
123 if (buf[len - 1] == '\n')
124 buf[len - 1] = '\0';
125
126 for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
127 tokens[i] = strsep(&pbuf, ",");
128
129 param = &ubiblock_param[ubiblock_devs];
130 if (tokens[1]) {
131 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
132 ret = kstrtoint(tokens[0], 10, ¶m->ubi_num);
133 if (ret < 0)
134 return -EINVAL;
135
136 /* Second param can be a number or a name */
137 ret = kstrtoint(tokens[1], 10, ¶m->vol_id);
138 if (ret < 0) {
139 param->vol_id = -1;
140 strcpy(param->name, tokens[1]);
141 }
142
143 } else {
144 /* One parameter: must be device path */
145 strcpy(param->name, tokens[0]);
146 param->ubi_num = -1;
147 param->vol_id = -1;
148 }
149
150 ubiblock_devs++;
151
152 return 0;
153}
154
155static const struct kernel_param_ops ubiblock_param_ops = {
156 .set = ubiblock_set_param,
157};
158module_param_cb(block, &ubiblock_param_ops, NULL, 0);
159MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
160 "Multiple \"block\" parameters may be specified.\n"
161 "UBI volumes may be specified by their number, name, or path to the device node.\n"
162 "Examples\n"
163 "Using the UBI volume path:\n"
164 "ubi.block=/dev/ubi0_0\n"
165 "Using the UBI device, and the volume name:\n"
166 "ubi.block=0,rootfs\n"
167 "Using both UBI device number and UBI volume number:\n"
168 "ubi.block=0,0\n");
169
170static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
171{
172 struct ubiblock *dev;
173
174 list_for_each_entry(dev, &ubiblock_devices, list)
175 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
176 return dev;
177 return NULL;
178}
179
180static blk_status_t ubiblock_read(struct request *req)
181{
182 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
183 struct ubiblock *dev = req->q->queuedata;
184 u64 pos = blk_rq_pos(req) << 9;
185 int to_read = blk_rq_bytes(req);
186 int bytes_left = to_read;
187 /* Get LEB:offset address to read from */
188 int offset = do_div(pos, dev->leb_size);
189 int leb = pos;
190 struct req_iterator iter;
191 struct bio_vec bvec;
192 int ret;
193
194 blk_mq_start_request(req);
195
196 /*
197 * It is safe to ignore the return value of blk_rq_map_sg() because
198 * the number of sg entries is limited to UBI_MAX_SG_COUNT
199 * and ubi_read_sg() will check that limit.
200 */
201 ubi_sgl_init(&pdu->usgl);
202 blk_rq_map_sg(req->q, req, pdu->usgl.sg);
203
204 while (bytes_left) {
205 /*
206 * We can only read one LEB at a time. Therefore if the read
207 * length is larger than one LEB size, we split the operation.
208 */
209 if (offset + to_read > dev->leb_size)
210 to_read = dev->leb_size - offset;
211
212 ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
213 if (ret < 0)
214 break;
215
216 bytes_left -= to_read;
217 to_read = bytes_left;
218 leb += 1;
219 offset = 0;
220 }
221
222 rq_for_each_segment(bvec, req, iter)
223 flush_dcache_page(bvec.bv_page);
224
225 blk_mq_end_request(req, errno_to_blk_status(ret));
226
227 return BLK_STS_OK;
228}
229
230static int ubiblock_open(struct gendisk *disk, blk_mode_t mode)
231{
232 struct ubiblock *dev = disk->private_data;
233 int ret;
234
235 mutex_lock(&dev->dev_mutex);
236 if (dev->refcnt > 0) {
237 /*
238 * The volume is already open, just increase the reference
239 * counter.
240 */
241 goto out_done;
242 }
243
244 /*
245 * We want users to be aware they should only mount us as read-only.
246 * It's just a paranoid check, as write requests will get rejected
247 * in any case.
248 */
249 if (mode & BLK_OPEN_WRITE) {
250 ret = -EROFS;
251 goto out_unlock;
252 }
253 dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
254 if (IS_ERR(dev->desc)) {
255 dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
256 dev->ubi_num, dev->vol_id);
257 ret = PTR_ERR(dev->desc);
258 dev->desc = NULL;
259 goto out_unlock;
260 }
261
262out_done:
263 dev->refcnt++;
264 mutex_unlock(&dev->dev_mutex);
265 return 0;
266
267out_unlock:
268 mutex_unlock(&dev->dev_mutex);
269 return ret;
270}
271
272static void ubiblock_release(struct gendisk *gd)
273{
274 struct ubiblock *dev = gd->private_data;
275
276 mutex_lock(&dev->dev_mutex);
277 dev->refcnt--;
278 if (dev->refcnt == 0) {
279 ubi_close_volume(dev->desc);
280 dev->desc = NULL;
281 }
282 mutex_unlock(&dev->dev_mutex);
283}
284
285static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
286{
287 /* Some tools might require this information */
288 geo->heads = 1;
289 geo->cylinders = 1;
290 geo->sectors = get_capacity(bdev->bd_disk);
291 geo->start = 0;
292 return 0;
293}
294
295static const struct block_device_operations ubiblock_ops = {
296 .owner = THIS_MODULE,
297 .open = ubiblock_open,
298 .release = ubiblock_release,
299 .getgeo = ubiblock_getgeo,
300};
301
302static blk_status_t ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
303 const struct blk_mq_queue_data *bd)
304{
305 switch (req_op(bd->rq)) {
306 case REQ_OP_READ:
307 return ubiblock_read(bd->rq);
308 default:
309 return BLK_STS_IOERR;
310 }
311}
312
313static int ubiblock_init_request(struct blk_mq_tag_set *set,
314 struct request *req, unsigned int hctx_idx,
315 unsigned int numa_node)
316{
317 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
318
319 sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
320 return 0;
321}
322
323static const struct blk_mq_ops ubiblock_mq_ops = {
324 .queue_rq = ubiblock_queue_rq,
325 .init_request = ubiblock_init_request,
326};
327
328static int calc_disk_capacity(struct ubi_volume_info *vi, u64 *disk_capacity)
329{
330 u64 size = vi->used_bytes >> 9;
331
332 if (vi->used_bytes % 512) {
333 if (vi->vol_type == UBI_DYNAMIC_VOLUME)
334 pr_warn("UBI: block: volume size is not a multiple of 512, last %llu bytes are ignored!\n",
335 vi->used_bytes - (size << 9));
336 else
337 pr_info("UBI: block: volume size is not a multiple of 512, last %llu bytes are ignored!\n",
338 vi->used_bytes - (size << 9));
339 }
340
341 if ((sector_t)size != size)
342 return -EFBIG;
343
344 *disk_capacity = size;
345
346 return 0;
347}
348
349int ubiblock_create(struct ubi_volume_info *vi)
350{
351 struct ubiblock *dev;
352 struct gendisk *gd;
353 u64 disk_capacity;
354 int ret;
355
356 ret = calc_disk_capacity(vi, &disk_capacity);
357 if (ret) {
358 return ret;
359 }
360
361 /* Check that the volume isn't already handled */
362 mutex_lock(&devices_mutex);
363 if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
364 ret = -EEXIST;
365 goto out_unlock;
366 }
367
368 dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
369 if (!dev) {
370 ret = -ENOMEM;
371 goto out_unlock;
372 }
373
374 mutex_init(&dev->dev_mutex);
375
376 dev->ubi_num = vi->ubi_num;
377 dev->vol_id = vi->vol_id;
378 dev->leb_size = vi->usable_leb_size;
379
380 dev->tag_set.ops = &ubiblock_mq_ops;
381 dev->tag_set.queue_depth = 64;
382 dev->tag_set.numa_node = NUMA_NO_NODE;
383 dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING;
384 dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
385 dev->tag_set.driver_data = dev;
386 dev->tag_set.nr_hw_queues = 1;
387
388 ret = blk_mq_alloc_tag_set(&dev->tag_set);
389 if (ret) {
390 dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
391 goto out_free_dev;
392 }
393
394
395 /* Initialize the gendisk of this ubiblock device */
396 gd = blk_mq_alloc_disk(&dev->tag_set, dev);
397 if (IS_ERR(gd)) {
398 ret = PTR_ERR(gd);
399 goto out_free_tags;
400 }
401
402 gd->fops = &ubiblock_ops;
403 gd->major = ubiblock_major;
404 gd->minors = 1;
405 gd->first_minor = idr_alloc(&ubiblock_minor_idr, dev, 0, 0, GFP_KERNEL);
406 if (gd->first_minor < 0) {
407 dev_err(disk_to_dev(gd),
408 "block: dynamic minor allocation failed");
409 ret = -ENODEV;
410 goto out_cleanup_disk;
411 }
412 gd->flags |= GENHD_FL_NO_PART;
413 gd->private_data = dev;
414 sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
415 set_capacity(gd, disk_capacity);
416 dev->gd = gd;
417
418 dev->rq = gd->queue;
419 blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
420
421 list_add_tail(&dev->list, &ubiblock_devices);
422
423 /* Must be the last step: anyone can call file ops from now on */
424 ret = device_add_disk(vi->dev, dev->gd, NULL);
425 if (ret)
426 goto out_remove_minor;
427
428 dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
429 dev->ubi_num, dev->vol_id, vi->name);
430 mutex_unlock(&devices_mutex);
431 return 0;
432
433out_remove_minor:
434 list_del(&dev->list);
435 idr_remove(&ubiblock_minor_idr, gd->first_minor);
436out_cleanup_disk:
437 put_disk(gd);
438out_free_tags:
439 blk_mq_free_tag_set(&dev->tag_set);
440out_free_dev:
441 kfree(dev);
442out_unlock:
443 mutex_unlock(&devices_mutex);
444
445 return ret;
446}
447
448static void ubiblock_cleanup(struct ubiblock *dev)
449{
450 int id = dev->gd->first_minor;
451
452 /* Stop new requests to arrive */
453 del_gendisk(dev->gd);
454 /* Finally destroy the blk queue */
455 dev_info(disk_to_dev(dev->gd), "released");
456 put_disk(dev->gd);
457 blk_mq_free_tag_set(&dev->tag_set);
458 idr_remove(&ubiblock_minor_idr, id);
459}
460
461int ubiblock_remove(struct ubi_volume_info *vi)
462{
463 struct ubiblock *dev;
464 int ret;
465
466 mutex_lock(&devices_mutex);
467 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
468 if (!dev) {
469 ret = -ENODEV;
470 goto out_unlock;
471 }
472
473 /* Found a device, let's lock it so we can check if it's busy */
474 mutex_lock(&dev->dev_mutex);
475 if (dev->refcnt > 0) {
476 ret = -EBUSY;
477 goto out_unlock_dev;
478 }
479
480 /* Remove from device list */
481 list_del(&dev->list);
482 ubiblock_cleanup(dev);
483 mutex_unlock(&dev->dev_mutex);
484 mutex_unlock(&devices_mutex);
485
486 kfree(dev);
487 return 0;
488
489out_unlock_dev:
490 mutex_unlock(&dev->dev_mutex);
491out_unlock:
492 mutex_unlock(&devices_mutex);
493 return ret;
494}
495
496static int ubiblock_resize(struct ubi_volume_info *vi)
497{
498 struct ubiblock *dev;
499 u64 disk_capacity;
500 int ret;
501
502 /*
503 * Need to lock the device list until we stop using the device,
504 * otherwise the device struct might get released in
505 * 'ubiblock_remove()'.
506 */
507 mutex_lock(&devices_mutex);
508 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
509 if (!dev) {
510 mutex_unlock(&devices_mutex);
511 return -ENODEV;
512 }
513
514 ret = calc_disk_capacity(vi, &disk_capacity);
515 if (ret) {
516 mutex_unlock(&devices_mutex);
517 if (ret == -EFBIG) {
518 dev_warn(disk_to_dev(dev->gd),
519 "the volume is too big (%d LEBs), cannot resize",
520 vi->size);
521 }
522 return ret;
523 }
524
525 mutex_lock(&dev->dev_mutex);
526
527 if (get_capacity(dev->gd) != disk_capacity) {
528 set_capacity(dev->gd, disk_capacity);
529 dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
530 vi->used_bytes);
531 }
532 mutex_unlock(&dev->dev_mutex);
533 mutex_unlock(&devices_mutex);
534 return 0;
535}
536
537static int ubiblock_notify(struct notifier_block *nb,
538 unsigned long notification_type, void *ns_ptr)
539{
540 struct ubi_notification *nt = ns_ptr;
541
542 switch (notification_type) {
543 case UBI_VOLUME_ADDED:
544 /*
545 * We want to enforce explicit block device creation for
546 * volumes, so when a volume is added we do nothing.
547 */
548 break;
549 case UBI_VOLUME_REMOVED:
550 ubiblock_remove(&nt->vi);
551 break;
552 case UBI_VOLUME_RESIZED:
553 ubiblock_resize(&nt->vi);
554 break;
555 case UBI_VOLUME_UPDATED:
556 /*
557 * If the volume is static, a content update might mean the
558 * size (i.e. used_bytes) was also changed.
559 */
560 if (nt->vi.vol_type == UBI_STATIC_VOLUME)
561 ubiblock_resize(&nt->vi);
562 break;
563 default:
564 break;
565 }
566 return NOTIFY_OK;
567}
568
569static struct notifier_block ubiblock_notifier = {
570 .notifier_call = ubiblock_notify,
571};
572
573static struct ubi_volume_desc * __init
574open_volume_desc(const char *name, int ubi_num, int vol_id)
575{
576 if (ubi_num == -1)
577 /* No ubi num, name must be a vol device path */
578 return ubi_open_volume_path(name, UBI_READONLY);
579 else if (vol_id == -1)
580 /* No vol_id, must be vol_name */
581 return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
582 else
583 return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
584}
585
586static void __init ubiblock_create_from_param(void)
587{
588 int i, ret = 0;
589 struct ubiblock_param *p;
590 struct ubi_volume_desc *desc;
591 struct ubi_volume_info vi;
592
593 /*
594 * If there is an error creating one of the ubiblocks, continue on to
595 * create the following ubiblocks. This helps in a circumstance where
596 * the kernel command-line specifies multiple block devices and some
597 * may be broken, but we still want the working ones to come up.
598 */
599 for (i = 0; i < ubiblock_devs; i++) {
600 p = &ubiblock_param[i];
601
602 desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
603 if (IS_ERR(desc)) {
604 pr_err(
605 "UBI: block: can't open volume on ubi%d_%d, err=%ld\n",
606 p->ubi_num, p->vol_id, PTR_ERR(desc));
607 continue;
608 }
609
610 ubi_get_volume_info(desc, &vi);
611 ubi_close_volume(desc);
612
613 ret = ubiblock_create(&vi);
614 if (ret) {
615 pr_err(
616 "UBI: block: can't add '%s' volume on ubi%d_%d, err=%d\n",
617 vi.name, p->ubi_num, p->vol_id, ret);
618 continue;
619 }
620 }
621}
622
623static void ubiblock_remove_all(void)
624{
625 struct ubiblock *next;
626 struct ubiblock *dev;
627
628 mutex_lock(&devices_mutex);
629 list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
630 /* The module is being forcefully removed */
631 WARN_ON(dev->desc);
632 /* Remove from device list */
633 list_del(&dev->list);
634 ubiblock_cleanup(dev);
635 kfree(dev);
636 }
637 mutex_unlock(&devices_mutex);
638}
639
640int __init ubiblock_init(void)
641{
642 int ret;
643
644 ubiblock_major = register_blkdev(0, "ubiblock");
645 if (ubiblock_major < 0)
646 return ubiblock_major;
647
648 /*
649 * Attach block devices from 'block=' module param.
650 * Even if one block device in the param list fails to come up,
651 * still allow the module to load and leave any others up.
652 */
653 ubiblock_create_from_param();
654
655 /*
656 * Block devices are only created upon user requests, so we ignore
657 * existing volumes.
658 */
659 ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
660 if (ret)
661 goto err_unreg;
662 return 0;
663
664err_unreg:
665 unregister_blkdev(ubiblock_major, "ubiblock");
666 ubiblock_remove_all();
667 return ret;
668}
669
670void __exit ubiblock_exit(void)
671{
672 ubi_unregister_volume_notifier(&ubiblock_notifier);
673 ubiblock_remove_all();
674 unregister_blkdev(ubiblock_major, "ubiblock");
675}