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_IDR(ubiblock_minor_idr);
103 /* Protects ubiblock_devices and ubiblock_minor_idr */
104 static DEFINE_MUTEX(devices_mutex);
105 static int ubiblock_major;
107 static int __init ubiblock_set_param(const char *val,
108 const struct kernel_param *kp)
112 struct ubiblock_param *param;
113 char buf[UBIBLOCK_PARAM_LEN];
114 char *pbuf = &buf[0];
115 char *tokens[UBIBLOCK_PARAM_COUNT];
120 len = strnlen(val, UBIBLOCK_PARAM_LEN);
122 pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
126 if (len == UBIBLOCK_PARAM_LEN) {
127 pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
128 val, UBIBLOCK_PARAM_LEN);
134 /* Get rid of the final newline */
135 if (buf[len - 1] == '\n')
138 for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
139 tokens[i] = strsep(&pbuf, ",");
141 param = &ubiblock_param[ubiblock_devs];
143 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
144 ret = kstrtoint(tokens[0], 10, ¶m->ubi_num);
148 /* Second param can be a number or a name */
149 ret = kstrtoint(tokens[1], 10, ¶m->vol_id);
152 strcpy(param->name, tokens[1]);
156 /* One parameter: must be device path */
157 strcpy(param->name, tokens[0]);
167 static const struct kernel_param_ops ubiblock_param_ops = {
168 .set = ubiblock_set_param,
170 module_param_cb(block, &ubiblock_param_ops, NULL, 0);
171 MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
172 "Multiple \"block\" parameters may be specified.\n"
173 "UBI volumes may be specified by their number, name, or path to the device node.\n"
175 "Using the UBI volume path:\n"
176 "ubi.block=/dev/ubi0_0\n"
177 "Using the UBI device, and the volume name:\n"
178 "ubi.block=0,rootfs\n"
179 "Using both UBI device number and UBI volume number:\n"
182 static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
184 struct ubiblock *dev;
186 list_for_each_entry(dev, &ubiblock_devices, list)
187 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
192 static int ubiblock_read(struct ubiblock_pdu *pdu)
194 int ret, leb, offset, bytes_left, to_read;
196 struct request *req = blk_mq_rq_from_pdu(pdu);
197 struct ubiblock *dev = req->q->queuedata;
199 to_read = blk_rq_bytes(req);
200 pos = blk_rq_pos(req) << 9;
202 /* Get LEB:offset address to read from */
203 offset = do_div(pos, dev->leb_size);
205 bytes_left = to_read;
209 * We can only read one LEB at a time. Therefore if the read
210 * length is larger than one LEB size, we split the operation.
212 if (offset + to_read > dev->leb_size)
213 to_read = dev->leb_size - offset;
215 ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
219 bytes_left -= to_read;
220 to_read = bytes_left;
227 static int ubiblock_open(struct block_device *bdev, fmode_t mode)
229 struct ubiblock *dev = bdev->bd_disk->private_data;
232 mutex_lock(&dev->dev_mutex);
233 if (dev->refcnt > 0) {
235 * The volume is already open, just increase the reference
242 * We want users to be aware they should only mount us as read-only.
243 * It's just a paranoid check, as write requests will get rejected
246 if (mode & FMODE_WRITE) {
251 dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
252 if (IS_ERR(dev->desc)) {
253 dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
254 dev->ubi_num, dev->vol_id);
255 ret = PTR_ERR(dev->desc);
262 mutex_unlock(&dev->dev_mutex);
266 mutex_unlock(&dev->dev_mutex);
270 static void ubiblock_release(struct gendisk *gd, fmode_t mode)
272 struct ubiblock *dev = gd->private_data;
274 mutex_lock(&dev->dev_mutex);
276 if (dev->refcnt == 0) {
277 ubi_close_volume(dev->desc);
280 mutex_unlock(&dev->dev_mutex);
283 static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
285 /* Some tools might require this information */
288 geo->sectors = get_capacity(bdev->bd_disk);
293 static const struct block_device_operations ubiblock_ops = {
294 .owner = THIS_MODULE,
295 .open = ubiblock_open,
296 .release = ubiblock_release,
297 .getgeo = ubiblock_getgeo,
300 static void ubiblock_do_work(struct work_struct *work)
303 struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
304 struct request *req = blk_mq_rq_from_pdu(pdu);
306 blk_mq_start_request(req);
309 * It is safe to ignore the return value of blk_rq_map_sg() because
310 * the number of sg entries is limited to UBI_MAX_SG_COUNT
311 * and ubi_read_sg() will check that limit.
313 blk_rq_map_sg(req->q, req, pdu->usgl.sg);
315 ret = ubiblock_read(pdu);
316 rq_flush_dcache_pages(req);
318 blk_mq_end_request(req, errno_to_blk_status(ret));
321 static blk_status_t ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
322 const struct blk_mq_queue_data *bd)
324 struct request *req = bd->rq;
325 struct ubiblock *dev = hctx->queue->queuedata;
326 struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
328 switch (req_op(req)) {
330 ubi_sgl_init(&pdu->usgl);
331 queue_work(dev->wq, &pdu->work);
334 return BLK_STS_IOERR;
339 static int ubiblock_init_request(struct blk_mq_tag_set *set,
340 struct request *req, unsigned int hctx_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 const struct blk_mq_ops ubiblock_mq_ops = {
352 .queue_rq = ubiblock_queue_rq,
353 .init_request = ubiblock_init_request,
356 int ubiblock_create(struct ubi_volume_info *vi)
358 struct ubiblock *dev;
360 u64 disk_capacity = vi->used_bytes >> 9;
363 if ((sector_t)disk_capacity != disk_capacity)
365 /* Check that the volume isn't already handled */
366 mutex_lock(&devices_mutex);
367 if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
372 dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
378 mutex_init(&dev->dev_mutex);
380 dev->ubi_num = vi->ubi_num;
381 dev->vol_id = vi->vol_id;
382 dev->leb_size = vi->usable_leb_size;
384 /* Initialize the gendisk of this ubiblock device */
387 pr_err("UBI: block: alloc_disk failed\n");
392 gd->fops = &ubiblock_ops;
393 gd->major = ubiblock_major;
394 gd->first_minor = idr_alloc(&ubiblock_minor_idr, dev, 0, 0, GFP_KERNEL);
395 if (gd->first_minor < 0) {
396 dev_err(disk_to_dev(gd),
397 "block: dynamic minor allocation failed");
401 gd->private_data = dev;
402 sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
403 set_capacity(gd, disk_capacity);
406 dev->tag_set.ops = &ubiblock_mq_ops;
407 dev->tag_set.queue_depth = 64;
408 dev->tag_set.numa_node = NUMA_NO_NODE;
409 dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
410 dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
411 dev->tag_set.driver_data = dev;
412 dev->tag_set.nr_hw_queues = 1;
414 ret = blk_mq_alloc_tag_set(&dev->tag_set);
416 dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
417 goto out_remove_minor;
420 dev->rq = blk_mq_init_queue(&dev->tag_set);
421 if (IS_ERR(dev->rq)) {
422 dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
423 ret = PTR_ERR(dev->rq);
426 blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
428 dev->rq->queuedata = dev;
429 dev->gd->queue = dev->rq;
432 * Create one workqueue per volume (per registered block device).
433 * Rembember workqueues are cheap, they're not threads.
435 dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
441 list_add_tail(&dev->list, &ubiblock_devices);
443 /* Must be the last step: anyone can call file ops from now on */
445 dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
446 dev->ubi_num, dev->vol_id, vi->name);
447 mutex_unlock(&devices_mutex);
451 blk_cleanup_queue(dev->rq);
453 blk_mq_free_tag_set(&dev->tag_set);
455 idr_remove(&ubiblock_minor_idr, gd->first_minor);
461 mutex_unlock(&devices_mutex);
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;
485 mutex_lock(&devices_mutex);
486 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
492 /* Found a device, let's lock it so we can check if it's busy */
493 mutex_lock(&dev->dev_mutex);
494 if (dev->refcnt > 0) {
499 /* Remove from device list */
500 list_del(&dev->list);
501 ubiblock_cleanup(dev);
502 mutex_unlock(&dev->dev_mutex);
503 mutex_unlock(&devices_mutex);
509 mutex_unlock(&dev->dev_mutex);
511 mutex_unlock(&devices_mutex);
515 static int ubiblock_resize(struct ubi_volume_info *vi)
517 struct ubiblock *dev;
518 u64 disk_capacity = vi->used_bytes >> 9;
521 * Need to lock the device list until we stop using the device,
522 * otherwise the device struct might get released in
523 * 'ubiblock_remove()'.
525 mutex_lock(&devices_mutex);
526 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
528 mutex_unlock(&devices_mutex);
531 if ((sector_t)disk_capacity != disk_capacity) {
532 mutex_unlock(&devices_mutex);
533 dev_warn(disk_to_dev(dev->gd), "the volume is too big (%d LEBs), cannot resize",
538 mutex_lock(&dev->dev_mutex);
540 if (get_capacity(dev->gd) != disk_capacity) {
541 set_capacity(dev->gd, disk_capacity);
542 dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
545 mutex_unlock(&dev->dev_mutex);
546 mutex_unlock(&devices_mutex);
550 static int ubiblock_notify(struct notifier_block *nb,
551 unsigned long notification_type, void *ns_ptr)
553 struct ubi_notification *nt = ns_ptr;
555 switch (notification_type) {
556 case UBI_VOLUME_ADDED:
558 * We want to enforce explicit block device creation for
559 * volumes, so when a volume is added we do nothing.
562 case UBI_VOLUME_REMOVED:
563 ubiblock_remove(&nt->vi);
565 case UBI_VOLUME_RESIZED:
566 ubiblock_resize(&nt->vi);
568 case UBI_VOLUME_UPDATED:
570 * If the volume is static, a content update might mean the
571 * size (i.e. used_bytes) was also changed.
573 if (nt->vi.vol_type == UBI_STATIC_VOLUME)
574 ubiblock_resize(&nt->vi);
582 static struct notifier_block ubiblock_notifier = {
583 .notifier_call = ubiblock_notify,
586 static struct ubi_volume_desc * __init
587 open_volume_desc(const char *name, int ubi_num, int vol_id)
590 /* No ubi num, name must be a vol device path */
591 return ubi_open_volume_path(name, UBI_READONLY);
592 else if (vol_id == -1)
593 /* No vol_id, must be vol_name */
594 return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
596 return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
599 static void __init ubiblock_create_from_param(void)
602 struct ubiblock_param *p;
603 struct ubi_volume_desc *desc;
604 struct ubi_volume_info vi;
607 * If there is an error creating one of the ubiblocks, continue on to
608 * create the following ubiblocks. This helps in a circumstance where
609 * the kernel command-line specifies multiple block devices and some
610 * may be broken, but we still want the working ones to come up.
612 for (i = 0; i < ubiblock_devs; i++) {
613 p = &ubiblock_param[i];
615 desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
618 "UBI: block: can't open volume on ubi%d_%d, err=%ld\n",
619 p->ubi_num, p->vol_id, PTR_ERR(desc));
623 ubi_get_volume_info(desc, &vi);
624 ubi_close_volume(desc);
626 ret = ubiblock_create(&vi);
629 "UBI: block: can't add '%s' volume on ubi%d_%d, err=%d\n",
630 vi.name, p->ubi_num, p->vol_id, ret);
636 static void ubiblock_remove_all(void)
638 struct ubiblock *next;
639 struct ubiblock *dev;
641 mutex_lock(&devices_mutex);
642 list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
643 /* The module is being forcefully removed */
645 /* Remove from device list */
646 list_del(&dev->list);
647 ubiblock_cleanup(dev);
650 mutex_unlock(&devices_mutex);
653 int __init ubiblock_init(void)
657 ubiblock_major = register_blkdev(0, "ubiblock");
658 if (ubiblock_major < 0)
659 return ubiblock_major;
662 * Attach block devices from 'block=' module param.
663 * Even if one block device in the param list fails to come up,
664 * still allow the module to load and leave any others up.
666 ubiblock_create_from_param();
669 * Block devices are only created upon user requests, so we ignore
672 ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
678 unregister_blkdev(ubiblock_major, "ubiblock");
679 ubiblock_remove_all();
683 void __exit ubiblock_exit(void)
685 ubi_unregister_volume_notifier(&ubiblock_notifier);
686 ubiblock_remove_all();
687 unregister_blkdev(ubiblock_major, "ubiblock");