2 * Copyright (c) 2014 Ezequiel Garcia
3 * Copyright (c) 2011 Free Electrons
5 * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
6 * Copyright (c) International Business Machines Corp., 2006
7 * Copyright (c) Nokia Corporation, 2007
8 * Authors: Artem Bityutskiy, Frank Haverkamp
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation, version 2.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
17 * the GNU General Public License for more details.
21 * Read-only block devices on top of UBI volumes
23 * A simple implementation to allow a block device to be layered on top of a
24 * UBI volume. The implementation is provided by creating a static 1-to-1
25 * mapping between the block device and the UBI volume.
27 * The addressed byte is obtained from the addressed block sector, which is
28 * mapped linearly into the corresponding LEB:
30 * LEB number = addressed byte / LEB size
32 * This feature is compiled in the UBI core, and adds a 'block' parameter
33 * to allow early creation of block devices on top of UBI volumes. Runtime
34 * block creation/removal for UBI volumes is provided through two UBI ioctls:
35 * UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
38 #include <linux/module.h>
39 #include <linux/init.h>
40 #include <linux/err.h>
41 #include <linux/kernel.h>
42 #include <linux/list.h>
43 #include <linux/mutex.h>
44 #include <linux/slab.h>
45 #include <linux/mtd/ubi.h>
46 #include <linux/workqueue.h>
47 #include <linux/blkdev.h>
48 #include <linux/blk-mq.h>
49 #include <linux/hdreg.h>
50 #include <linux/scatterlist.h>
51 #include <asm/div64.h>
53 #include "ubi-media.h"
56 /* Maximum number of supported devices */
57 #define UBIBLOCK_MAX_DEVICES 32
59 /* Maximum length of the 'block=' parameter */
60 #define UBIBLOCK_PARAM_LEN 63
62 /* Maximum number of comma-separated items in the 'block=' parameter */
63 #define UBIBLOCK_PARAM_COUNT 2
65 struct ubiblock_param {
68 char name[UBIBLOCK_PARAM_LEN+1];
72 struct work_struct work;
76 /* Numbers of elements set in the @ubiblock_param array */
77 static int ubiblock_devs __initdata;
79 /* MTD devices specification parameters */
80 static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
83 struct ubi_volume_desc *desc;
90 struct request_queue *rq;
92 struct workqueue_struct *wq;
94 struct mutex dev_mutex;
95 struct list_head list;
96 struct blk_mq_tag_set tag_set;
99 /* Linked list of all ubiblock instances */
100 static LIST_HEAD(ubiblock_devices);
101 static DEFINE_MUTEX(devices_mutex);
102 static int ubiblock_major;
104 static int __init ubiblock_set_param(const char *val,
105 const struct kernel_param *kp)
109 struct ubiblock_param *param;
110 char buf[UBIBLOCK_PARAM_LEN];
111 char *pbuf = &buf[0];
112 char *tokens[UBIBLOCK_PARAM_COUNT];
117 len = strnlen(val, UBIBLOCK_PARAM_LEN);
119 pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
123 if (len == UBIBLOCK_PARAM_LEN) {
124 pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
125 val, UBIBLOCK_PARAM_LEN);
131 /* Get rid of the final newline */
132 if (buf[len - 1] == '\n')
135 for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
136 tokens[i] = strsep(&pbuf, ",");
138 param = &ubiblock_param[ubiblock_devs];
140 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
141 ret = kstrtoint(tokens[0], 10, ¶m->ubi_num);
145 /* Second param can be a number or a name */
146 ret = kstrtoint(tokens[1], 10, ¶m->vol_id);
149 strcpy(param->name, tokens[1]);
153 /* One parameter: must be device path */
154 strcpy(param->name, tokens[0]);
164 static struct kernel_param_ops ubiblock_param_ops = {
165 .set = ubiblock_set_param,
167 module_param_cb(block, &ubiblock_param_ops, NULL, 0);
168 MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
169 "Multiple \"block\" parameters may be specified.\n"
170 "UBI volumes may be specified by their number, name, or path to the device node.\n"
172 "Using the UBI volume path:\n"
173 "ubi.block=/dev/ubi0_0\n"
174 "Using the UBI device, and the volume name:\n"
175 "ubi.block=0,rootfs\n"
176 "Using both UBI device number and UBI volume number:\n"
179 static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
181 struct ubiblock *dev;
183 list_for_each_entry(dev, &ubiblock_devices, list)
184 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
189 static int ubiblock_read(struct ubiblock_pdu *pdu)
191 int ret, leb, offset, bytes_left, to_read;
193 struct request *req = blk_mq_rq_from_pdu(pdu);
194 struct ubiblock *dev = req->q->queuedata;
196 to_read = blk_rq_bytes(req);
197 pos = blk_rq_pos(req) << 9;
199 /* Get LEB:offset address to read from */
200 offset = do_div(pos, dev->leb_size);
202 bytes_left = to_read;
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.
209 if (offset + to_read > dev->leb_size)
210 to_read = dev->leb_size - offset;
212 ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
216 bytes_left -= to_read;
217 to_read = bytes_left;
224 static int ubiblock_open(struct block_device *bdev, fmode_t mode)
226 struct ubiblock *dev = bdev->bd_disk->private_data;
229 mutex_lock(&dev->dev_mutex);
230 if (dev->refcnt > 0) {
232 * The volume is already open, just increase the reference
239 * We want users to be aware they should only mount us as read-only.
240 * It's just a paranoid check, as write requests will get rejected
243 if (mode & FMODE_WRITE) {
248 dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
249 if (IS_ERR(dev->desc)) {
250 dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
251 dev->ubi_num, dev->vol_id);
252 ret = PTR_ERR(dev->desc);
259 mutex_unlock(&dev->dev_mutex);
263 mutex_unlock(&dev->dev_mutex);
267 static void ubiblock_release(struct gendisk *gd, fmode_t mode)
269 struct ubiblock *dev = gd->private_data;
271 mutex_lock(&dev->dev_mutex);
273 if (dev->refcnt == 0) {
274 ubi_close_volume(dev->desc);
277 mutex_unlock(&dev->dev_mutex);
280 static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
282 /* Some tools might require this information */
285 geo->sectors = get_capacity(bdev->bd_disk);
290 static const struct block_device_operations ubiblock_ops = {
291 .owner = THIS_MODULE,
292 .open = ubiblock_open,
293 .release = ubiblock_release,
294 .getgeo = ubiblock_getgeo,
297 static void ubiblock_do_work(struct work_struct *work)
300 struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
301 struct request *req = blk_mq_rq_from_pdu(pdu);
303 blk_mq_start_request(req);
304 blk_rq_map_sg(req->q, req, pdu->usgl.sg);
306 ret = ubiblock_read(pdu);
307 blk_mq_end_request(req, ret);
310 static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
311 const struct blk_mq_queue_data *bd)
313 struct request *req = bd->rq;
314 struct ubiblock *dev = hctx->queue->queuedata;
315 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
317 if (req->cmd_type != REQ_TYPE_FS)
318 return BLK_MQ_RQ_QUEUE_ERROR;
320 if (rq_data_dir(req) != READ)
321 return BLK_MQ_RQ_QUEUE_ERROR; /* Write not implemented */
323 ubi_sgl_init(&pdu->usgl);
324 queue_work(dev->wq, &pdu->work);
326 return BLK_MQ_RQ_QUEUE_OK;
329 static int ubiblock_init_request(void *data, struct request *req,
330 unsigned int hctx_idx,
331 unsigned int request_idx,
332 unsigned int numa_node)
334 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
336 sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
337 INIT_WORK(&pdu->work, ubiblock_do_work);
342 static struct blk_mq_ops ubiblock_mq_ops = {
343 .queue_rq = ubiblock_queue_rq,
344 .init_request = ubiblock_init_request,
345 .map_queue = blk_mq_map_queue,
348 int ubiblock_create(struct ubi_volume_info *vi)
350 struct ubiblock *dev;
352 u64 disk_capacity = vi->used_bytes >> 9;
355 if ((sector_t)disk_capacity != disk_capacity)
357 /* Check that the volume isn't already handled */
358 mutex_lock(&devices_mutex);
359 if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
360 mutex_unlock(&devices_mutex);
363 mutex_unlock(&devices_mutex);
365 dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
369 mutex_init(&dev->dev_mutex);
371 dev->ubi_num = vi->ubi_num;
372 dev->vol_id = vi->vol_id;
373 dev->leb_size = vi->usable_leb_size;
375 /* Initialize the gendisk of this ubiblock device */
378 pr_err("UBI: block: alloc_disk failed");
383 gd->fops = &ubiblock_ops;
384 gd->major = ubiblock_major;
385 gd->first_minor = dev->ubi_num * UBI_MAX_VOLUMES + dev->vol_id;
386 gd->private_data = dev;
387 sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
388 set_capacity(gd, disk_capacity);
391 dev->tag_set.ops = &ubiblock_mq_ops;
392 dev->tag_set.queue_depth = 64;
393 dev->tag_set.numa_node = NUMA_NO_NODE;
394 dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
395 dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
396 dev->tag_set.driver_data = dev;
397 dev->tag_set.nr_hw_queues = 1;
399 ret = blk_mq_alloc_tag_set(&dev->tag_set);
401 dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
405 dev->rq = blk_mq_init_queue(&dev->tag_set);
407 dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
411 blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
413 dev->rq->queuedata = dev;
414 dev->gd->queue = dev->rq;
417 * Create one workqueue per volume (per registered block device).
418 * Rembember workqueues are cheap, they're not threads.
420 dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
426 mutex_lock(&devices_mutex);
427 list_add_tail(&dev->list, &ubiblock_devices);
428 mutex_unlock(&devices_mutex);
430 /* Must be the last step: anyone can call file ops from now on */
432 dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
433 dev->ubi_num, dev->vol_id, vi->name);
437 blk_cleanup_queue(dev->rq);
439 blk_mq_free_tag_set(&dev->tag_set);
448 static void ubiblock_cleanup(struct ubiblock *dev)
450 /* Stop new requests to arrive */
451 del_gendisk(dev->gd);
452 /* Flush pending work */
453 destroy_workqueue(dev->wq);
454 /* Finally destroy the blk queue */
455 blk_cleanup_queue(dev->rq);
456 blk_mq_free_tag_set(&dev->tag_set);
457 dev_info(disk_to_dev(dev->gd), "released");
461 int ubiblock_remove(struct ubi_volume_info *vi)
463 struct ubiblock *dev;
465 mutex_lock(&devices_mutex);
466 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
468 mutex_unlock(&devices_mutex);
472 /* Found a device, let's lock it so we can check if it's busy */
473 mutex_lock(&dev->dev_mutex);
474 if (dev->refcnt > 0) {
475 mutex_unlock(&dev->dev_mutex);
476 mutex_unlock(&devices_mutex);
480 /* Remove from device list */
481 list_del(&dev->list);
482 mutex_unlock(&devices_mutex);
484 ubiblock_cleanup(dev);
485 mutex_unlock(&dev->dev_mutex);
490 static int ubiblock_resize(struct ubi_volume_info *vi)
492 struct ubiblock *dev;
493 u64 disk_capacity = vi->used_bytes >> 9;
496 * Need to lock the device list until we stop using the device,
497 * otherwise the device struct might get released in
498 * 'ubiblock_remove()'.
500 mutex_lock(&devices_mutex);
501 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
503 mutex_unlock(&devices_mutex);
506 if ((sector_t)disk_capacity != disk_capacity) {
507 mutex_unlock(&devices_mutex);
508 dev_warn(disk_to_dev(dev->gd), "the volume is too big (%d LEBs), cannot resize",
513 mutex_lock(&dev->dev_mutex);
515 if (get_capacity(dev->gd) != disk_capacity) {
516 set_capacity(dev->gd, disk_capacity);
517 dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
520 mutex_unlock(&dev->dev_mutex);
521 mutex_unlock(&devices_mutex);
525 static int ubiblock_notify(struct notifier_block *nb,
526 unsigned long notification_type, void *ns_ptr)
528 struct ubi_notification *nt = ns_ptr;
530 switch (notification_type) {
531 case UBI_VOLUME_ADDED:
533 * We want to enforce explicit block device creation for
534 * volumes, so when a volume is added we do nothing.
537 case UBI_VOLUME_REMOVED:
538 ubiblock_remove(&nt->vi);
540 case UBI_VOLUME_RESIZED:
541 ubiblock_resize(&nt->vi);
543 case UBI_VOLUME_UPDATED:
545 * If the volume is static, a content update might mean the
546 * size (i.e. used_bytes) was also changed.
548 if (nt->vi.vol_type == UBI_STATIC_VOLUME)
549 ubiblock_resize(&nt->vi);
557 static struct notifier_block ubiblock_notifier = {
558 .notifier_call = ubiblock_notify,
561 static struct ubi_volume_desc * __init
562 open_volume_desc(const char *name, int ubi_num, int vol_id)
565 /* No ubi num, name must be a vol device path */
566 return ubi_open_volume_path(name, UBI_READONLY);
567 else if (vol_id == -1)
568 /* No vol_id, must be vol_name */
569 return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
571 return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
574 static int __init ubiblock_create_from_param(void)
577 struct ubiblock_param *p;
578 struct ubi_volume_desc *desc;
579 struct ubi_volume_info vi;
581 for (i = 0; i < ubiblock_devs; i++) {
582 p = &ubiblock_param[i];
584 desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
586 pr_err("UBI: block: can't open volume, err=%ld\n",
592 ubi_get_volume_info(desc, &vi);
593 ubi_close_volume(desc);
595 ret = ubiblock_create(&vi);
597 pr_err("UBI: block: can't add '%s' volume, err=%d\n",
605 static void ubiblock_remove_all(void)
607 struct ubiblock *next;
608 struct ubiblock *dev;
610 list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
611 /* The module is being forcefully removed */
613 /* Remove from device list */
614 list_del(&dev->list);
615 ubiblock_cleanup(dev);
620 int __init ubiblock_init(void)
624 ubiblock_major = register_blkdev(0, "ubiblock");
625 if (ubiblock_major < 0)
626 return ubiblock_major;
628 /* Attach block devices from 'block=' module param */
629 ret = ubiblock_create_from_param();
634 * Block devices are only created upon user requests, so we ignore
637 ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
643 unregister_blkdev(ubiblock_major, "ubiblock");
645 ubiblock_remove_all();
649 void __exit ubiblock_exit(void)
651 ubi_unregister_volume_notifier(&ubiblock_notifier);
652 ubiblock_remove_all();
653 unregister_blkdev(ubiblock_major, "ubiblock");