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 <linux/idr.h>
52 #include <asm/div64.h>
54 #include "ubi-media.h"
57 /* Maximum number of supported devices */
58 #define UBIBLOCK_MAX_DEVICES 32
60 /* Maximum length of the 'block=' parameter */
61 #define UBIBLOCK_PARAM_LEN 63
63 /* Maximum number of comma-separated items in the 'block=' parameter */
64 #define UBIBLOCK_PARAM_COUNT 2
66 struct ubiblock_param {
69 char name[UBIBLOCK_PARAM_LEN+1];
73 struct work_struct work;
77 /* Numbers of elements set in the @ubiblock_param array */
78 static int ubiblock_devs __initdata;
80 /* MTD devices specification parameters */
81 static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
84 struct ubi_volume_desc *desc;
91 struct request_queue *rq;
93 struct workqueue_struct *wq;
95 struct mutex dev_mutex;
96 struct list_head list;
97 struct blk_mq_tag_set tag_set;
100 /* Linked list of all ubiblock instances */
101 static LIST_HEAD(ubiblock_devices);
102 static DEFINE_MUTEX(devices_mutex);
103 static int ubiblock_major;
105 static int __init ubiblock_set_param(const char *val,
106 const struct kernel_param *kp)
110 struct ubiblock_param *param;
111 char buf[UBIBLOCK_PARAM_LEN];
112 char *pbuf = &buf[0];
113 char *tokens[UBIBLOCK_PARAM_COUNT];
118 len = strnlen(val, UBIBLOCK_PARAM_LEN);
120 pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
124 if (len == UBIBLOCK_PARAM_LEN) {
125 pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
126 val, UBIBLOCK_PARAM_LEN);
132 /* Get rid of the final newline */
133 if (buf[len - 1] == '\n')
136 for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
137 tokens[i] = strsep(&pbuf, ",");
139 param = &ubiblock_param[ubiblock_devs];
141 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
142 ret = kstrtoint(tokens[0], 10, ¶m->ubi_num);
146 /* Second param can be a number or a name */
147 ret = kstrtoint(tokens[1], 10, ¶m->vol_id);
150 strcpy(param->name, tokens[1]);
154 /* One parameter: must be device path */
155 strcpy(param->name, tokens[0]);
165 static const struct kernel_param_ops ubiblock_param_ops = {
166 .set = ubiblock_set_param,
168 module_param_cb(block, &ubiblock_param_ops, NULL, 0);
169 MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
170 "Multiple \"block\" parameters may be specified.\n"
171 "UBI volumes may be specified by their number, name, or path to the device node.\n"
173 "Using the UBI volume path:\n"
174 "ubi.block=/dev/ubi0_0\n"
175 "Using the UBI device, and the volume name:\n"
176 "ubi.block=0,rootfs\n"
177 "Using both UBI device number and UBI volume number:\n"
180 static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
182 struct ubiblock *dev;
184 list_for_each_entry(dev, &ubiblock_devices, list)
185 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
190 static int ubiblock_read(struct ubiblock_pdu *pdu)
192 int ret, leb, offset, bytes_left, to_read;
194 struct request *req = blk_mq_rq_from_pdu(pdu);
195 struct ubiblock *dev = req->q->queuedata;
197 to_read = blk_rq_bytes(req);
198 pos = blk_rq_pos(req) << 9;
200 /* Get LEB:offset address to read from */
201 offset = do_div(pos, dev->leb_size);
203 bytes_left = to_read;
207 * We can only read one LEB at a time. Therefore if the read
208 * length is larger than one LEB size, we split the operation.
210 if (offset + to_read > dev->leb_size)
211 to_read = dev->leb_size - offset;
213 ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
217 bytes_left -= to_read;
218 to_read = bytes_left;
225 static int ubiblock_open(struct block_device *bdev, fmode_t mode)
227 struct ubiblock *dev = bdev->bd_disk->private_data;
230 mutex_lock(&dev->dev_mutex);
231 if (dev->refcnt > 0) {
233 * The volume is already open, just increase the reference
240 * We want users to be aware they should only mount us as read-only.
241 * It's just a paranoid check, as write requests will get rejected
244 if (mode & FMODE_WRITE) {
249 dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
250 if (IS_ERR(dev->desc)) {
251 dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
252 dev->ubi_num, dev->vol_id);
253 ret = PTR_ERR(dev->desc);
260 mutex_unlock(&dev->dev_mutex);
264 mutex_unlock(&dev->dev_mutex);
268 static void ubiblock_release(struct gendisk *gd, fmode_t mode)
270 struct ubiblock *dev = gd->private_data;
272 mutex_lock(&dev->dev_mutex);
274 if (dev->refcnt == 0) {
275 ubi_close_volume(dev->desc);
278 mutex_unlock(&dev->dev_mutex);
281 static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
283 /* Some tools might require this information */
286 geo->sectors = get_capacity(bdev->bd_disk);
291 static const struct block_device_operations ubiblock_ops = {
292 .owner = THIS_MODULE,
293 .open = ubiblock_open,
294 .release = ubiblock_release,
295 .getgeo = ubiblock_getgeo,
298 static void ubiblock_do_work(struct work_struct *work)
301 struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
302 struct request *req = blk_mq_rq_from_pdu(pdu);
304 blk_mq_start_request(req);
307 * It is safe to ignore the return value of blk_rq_map_sg() because
308 * the number of sg entries is limited to UBI_MAX_SG_COUNT
309 * and ubi_read_sg() will check that limit.
311 blk_rq_map_sg(req->q, req, pdu->usgl.sg);
313 ret = ubiblock_read(pdu);
314 rq_flush_dcache_pages(req);
316 blk_mq_end_request(req, ret);
319 static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
320 const struct blk_mq_queue_data *bd)
322 struct request *req = bd->rq;
323 struct ubiblock *dev = hctx->queue->queuedata;
324 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
326 if (req->cmd_type != REQ_TYPE_FS)
327 return BLK_MQ_RQ_QUEUE_ERROR;
329 if (rq_data_dir(req) != READ)
330 return BLK_MQ_RQ_QUEUE_ERROR; /* Write not implemented */
332 ubi_sgl_init(&pdu->usgl);
333 queue_work(dev->wq, &pdu->work);
335 return BLK_MQ_RQ_QUEUE_OK;
338 static int ubiblock_init_request(void *data, struct request *req,
339 unsigned int hctx_idx,
340 unsigned int request_idx,
341 unsigned int numa_node)
343 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
345 sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
346 INIT_WORK(&pdu->work, ubiblock_do_work);
351 static struct blk_mq_ops ubiblock_mq_ops = {
352 .queue_rq = ubiblock_queue_rq,
353 .init_request = ubiblock_init_request,
356 static DEFINE_IDR(ubiblock_minor_idr);
358 int ubiblock_create(struct ubi_volume_info *vi)
360 struct ubiblock *dev;
362 u64 disk_capacity = vi->used_bytes >> 9;
365 if ((sector_t)disk_capacity != disk_capacity)
367 /* Check that the volume isn't already handled */
368 mutex_lock(&devices_mutex);
369 if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
370 mutex_unlock(&devices_mutex);
373 mutex_unlock(&devices_mutex);
375 dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
379 mutex_init(&dev->dev_mutex);
381 dev->ubi_num = vi->ubi_num;
382 dev->vol_id = vi->vol_id;
383 dev->leb_size = vi->usable_leb_size;
385 /* Initialize the gendisk of this ubiblock device */
388 pr_err("UBI: block: alloc_disk failed");
393 gd->fops = &ubiblock_ops;
394 gd->major = ubiblock_major;
395 gd->first_minor = idr_alloc(&ubiblock_minor_idr, dev, 0, 0, GFP_KERNEL);
396 if (gd->first_minor < 0) {
397 dev_err(disk_to_dev(gd),
398 "block: dynamic minor allocation failed");
402 gd->private_data = dev;
403 sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
404 set_capacity(gd, disk_capacity);
407 dev->tag_set.ops = &ubiblock_mq_ops;
408 dev->tag_set.queue_depth = 64;
409 dev->tag_set.numa_node = NUMA_NO_NODE;
410 dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
411 dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
412 dev->tag_set.driver_data = dev;
413 dev->tag_set.nr_hw_queues = 1;
415 ret = blk_mq_alloc_tag_set(&dev->tag_set);
417 dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
418 goto out_remove_minor;
421 dev->rq = blk_mq_init_queue(&dev->tag_set);
422 if (IS_ERR(dev->rq)) {
423 dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
424 ret = PTR_ERR(dev->rq);
427 blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
429 dev->rq->queuedata = dev;
430 dev->gd->queue = dev->rq;
433 * Create one workqueue per volume (per registered block device).
434 * Rembember workqueues are cheap, they're not threads.
436 dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
442 mutex_lock(&devices_mutex);
443 list_add_tail(&dev->list, &ubiblock_devices);
444 mutex_unlock(&devices_mutex);
446 /* Must be the last step: anyone can call file ops from now on */
448 dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
449 dev->ubi_num, dev->vol_id, vi->name);
453 blk_cleanup_queue(dev->rq);
455 blk_mq_free_tag_set(&dev->tag_set);
457 idr_remove(&ubiblock_minor_idr, gd->first_minor);
466 static void ubiblock_cleanup(struct ubiblock *dev)
468 /* Stop new requests to arrive */
469 del_gendisk(dev->gd);
470 /* Flush pending work */
471 destroy_workqueue(dev->wq);
472 /* Finally destroy the blk queue */
473 blk_cleanup_queue(dev->rq);
474 blk_mq_free_tag_set(&dev->tag_set);
475 dev_info(disk_to_dev(dev->gd), "released");
476 idr_remove(&ubiblock_minor_idr, dev->gd->first_minor);
480 int ubiblock_remove(struct ubi_volume_info *vi)
482 struct ubiblock *dev;
484 mutex_lock(&devices_mutex);
485 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
487 mutex_unlock(&devices_mutex);
491 /* Found a device, let's lock it so we can check if it's busy */
492 mutex_lock(&dev->dev_mutex);
493 if (dev->refcnt > 0) {
494 mutex_unlock(&dev->dev_mutex);
495 mutex_unlock(&devices_mutex);
499 /* Remove from device list */
500 list_del(&dev->list);
501 mutex_unlock(&devices_mutex);
503 ubiblock_cleanup(dev);
504 mutex_unlock(&dev->dev_mutex);
509 static int ubiblock_resize(struct ubi_volume_info *vi)
511 struct ubiblock *dev;
512 u64 disk_capacity = vi->used_bytes >> 9;
515 * Need to lock the device list until we stop using the device,
516 * otherwise the device struct might get released in
517 * 'ubiblock_remove()'.
519 mutex_lock(&devices_mutex);
520 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
522 mutex_unlock(&devices_mutex);
525 if ((sector_t)disk_capacity != disk_capacity) {
526 mutex_unlock(&devices_mutex);
527 dev_warn(disk_to_dev(dev->gd), "the volume is too big (%d LEBs), cannot resize",
532 mutex_lock(&dev->dev_mutex);
534 if (get_capacity(dev->gd) != disk_capacity) {
535 set_capacity(dev->gd, disk_capacity);
536 dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
539 mutex_unlock(&dev->dev_mutex);
540 mutex_unlock(&devices_mutex);
544 static int ubiblock_notify(struct notifier_block *nb,
545 unsigned long notification_type, void *ns_ptr)
547 struct ubi_notification *nt = ns_ptr;
549 switch (notification_type) {
550 case UBI_VOLUME_ADDED:
552 * We want to enforce explicit block device creation for
553 * volumes, so when a volume is added we do nothing.
556 case UBI_VOLUME_REMOVED:
557 ubiblock_remove(&nt->vi);
559 case UBI_VOLUME_RESIZED:
560 ubiblock_resize(&nt->vi);
562 case UBI_VOLUME_UPDATED:
564 * If the volume is static, a content update might mean the
565 * size (i.e. used_bytes) was also changed.
567 if (nt->vi.vol_type == UBI_STATIC_VOLUME)
568 ubiblock_resize(&nt->vi);
576 static struct notifier_block ubiblock_notifier = {
577 .notifier_call = ubiblock_notify,
580 static struct ubi_volume_desc * __init
581 open_volume_desc(const char *name, int ubi_num, int vol_id)
584 /* No ubi num, name must be a vol device path */
585 return ubi_open_volume_path(name, UBI_READONLY);
586 else if (vol_id == -1)
587 /* No vol_id, must be vol_name */
588 return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
590 return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
593 static void __init ubiblock_create_from_param(void)
596 struct ubiblock_param *p;
597 struct ubi_volume_desc *desc;
598 struct ubi_volume_info vi;
601 * If there is an error creating one of the ubiblocks, continue on to
602 * create the following ubiblocks. This helps in a circumstance where
603 * the kernel command-line specifies multiple block devices and some
604 * may be broken, but we still want the working ones to come up.
606 for (i = 0; i < ubiblock_devs; i++) {
607 p = &ubiblock_param[i];
609 desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
612 "UBI: block: can't open volume on ubi%d_%d, err=%ld",
613 p->ubi_num, p->vol_id, PTR_ERR(desc));
617 ubi_get_volume_info(desc, &vi);
618 ubi_close_volume(desc);
620 ret = ubiblock_create(&vi);
623 "UBI: block: can't add '%s' volume on ubi%d_%d, err=%d",
624 vi.name, p->ubi_num, p->vol_id, ret);
630 static void ubiblock_remove_all(void)
632 struct ubiblock *next;
633 struct ubiblock *dev;
635 list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
636 /* The module is being forcefully removed */
638 /* Remove from device list */
639 list_del(&dev->list);
640 ubiblock_cleanup(dev);
645 int __init ubiblock_init(void)
649 ubiblock_major = register_blkdev(0, "ubiblock");
650 if (ubiblock_major < 0)
651 return ubiblock_major;
654 * Attach block devices from 'block=' module param.
655 * Even if one block device in the param list fails to come up,
656 * still allow the module to load and leave any others up.
658 ubiblock_create_from_param();
661 * Block devices are only created upon user requests, so we ignore
664 ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
670 unregister_blkdev(ubiblock_major, "ubiblock");
671 ubiblock_remove_all();
675 void __exit ubiblock_exit(void)
677 ubi_unregister_volume_notifier(&ubiblock_notifier);
678 ubiblock_remove_all();
679 unregister_blkdev(ubiblock_major, "ubiblock");