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|
/*
* Copyright (c) 2014 Ezequiel Garcia
* Copyright (c) 2011 Free Electrons
*
* Driver parameter handling strongly based on drivers/mtd/ubi/build.c
* Copyright (c) International Business Machines Corp., 2006
* Copyright (c) Nokia Corporation, 2007
* Authors: Artem Bityutskiy, Frank Haverkamp
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*/
/*
* Read-only block devices on top of UBI volumes
*
* A simple implementation to allow a block device to be layered on top of a
* UBI volume. The implementation is provided by creating a static 1-to-1
* mapping between the block device and the UBI volume.
*
* The addressed byte is obtained from the addressed block sector, which is
* mapped linearly into the corresponding LEB:
*
* LEB number = addressed byte / LEB size
*
* This feature is compiled in the UBI core, and adds a 'block' parameter
* to allow early creation of block devices on top of UBI volumes. Runtime
* block creation/removal for UBI volumes is provided through two UBI ioctls:
* UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/mtd/ubi.h>
#include <linux/workqueue.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/hdreg.h>
#include <linux/scatterlist.h>
#include <asm/div64.h>
#include "ubi-media.h"
#include "ubi.h"
/* Maximum number of supported devices */
#define UBIBLOCK_MAX_DEVICES 32
/* Maximum length of the 'block=' parameter */
#define UBIBLOCK_PARAM_LEN 63
/* Maximum number of comma-separated items in the 'block=' parameter */
#define UBIBLOCK_PARAM_COUNT 2
struct ubiblock_param {
int ubi_num;
int vol_id;
char name[UBIBLOCK_PARAM_LEN+1];
};
struct ubiblock_pdu {
struct work_struct work;
struct ubi_sgl usgl;
};
/* Numbers of elements set in the @ubiblock_param array */
static int ubiblock_devs __initdata;
/* MTD devices specification parameters */
static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
struct ubiblock {
struct ubi_volume_desc *desc;
int ubi_num;
int vol_id;
int refcnt;
int leb_size;
struct gendisk *gd;
struct request_queue *rq;
struct workqueue_struct *wq;
struct mutex dev_mutex;
struct list_head list;
struct blk_mq_tag_set tag_set;
};
/* Linked list of all ubiblock instances */
static LIST_HEAD(ubiblock_devices);
static DEFINE_MUTEX(devices_mutex);
static int ubiblock_major;
static int __init ubiblock_set_param(const char *val,
const struct kernel_param *kp)
{
int i, ret;
size_t len;
struct ubiblock_param *param;
char buf[UBIBLOCK_PARAM_LEN];
char *pbuf = &buf[0];
char *tokens[UBIBLOCK_PARAM_COUNT];
if (!val)
return -EINVAL;
len = strnlen(val, UBIBLOCK_PARAM_LEN);
if (len == 0) {
pr_warn("UBI: block: empty 'block=' parameter - ignored\n");
return 0;
}
if (len == UBIBLOCK_PARAM_LEN) {
pr_err("UBI: block: parameter \"%s\" is too long, max. is %d\n",
val, UBIBLOCK_PARAM_LEN);
return -EINVAL;
}
strcpy(buf, val);
/* Get rid of the final newline */
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
tokens[i] = strsep(&pbuf, ",");
param = &ubiblock_param[ubiblock_devs];
if (tokens[1]) {
/* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
ret = kstrtoint(tokens[0], 10, ¶m->ubi_num);
if (ret < 0)
return -EINVAL;
/* Second param can be a number or a name */
ret = kstrtoint(tokens[1], 10, ¶m->vol_id);
if (ret < 0) {
param->vol_id = -1;
strcpy(param->name, tokens[1]);
}
} else {
/* One parameter: must be device path */
strcpy(param->name, tokens[0]);
param->ubi_num = -1;
param->vol_id = -1;
}
ubiblock_devs++;
return 0;
}
static struct kernel_param_ops ubiblock_param_ops = {
.set = ubiblock_set_param,
};
module_param_cb(block, &ubiblock_param_ops, NULL, 0);
MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
"Multiple \"block\" parameters may be specified.\n"
"UBI volumes may be specified by their number, name, or path to the device node.\n"
"Examples\n"
"Using the UBI volume path:\n"
"ubi.block=/dev/ubi0_0\n"
"Using the UBI device, and the volume name:\n"
"ubi.block=0,rootfs\n"
"Using both UBI device number and UBI volume number:\n"
"ubi.block=0,0\n");
static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
{
struct ubiblock *dev;
list_for_each_entry(dev, &ubiblock_devices, list)
if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
return dev;
return NULL;
}
static int ubiblock_read(struct ubiblock_pdu *pdu)
{
int ret, leb, offset, bytes_left, to_read;
u64 pos;
struct request *req = blk_mq_rq_from_pdu(pdu);
struct ubiblock *dev = req->q->queuedata;
to_read = blk_rq_bytes(req);
pos = blk_rq_pos(req) << 9;
/* Get LEB:offset address to read from */
offset = do_div(pos, dev->leb_size);
leb = pos;
bytes_left = to_read;
while (bytes_left) {
/*
* We can only read one LEB at a time. Therefore if the read
* length is larger than one LEB size, we split the operation.
*/
if (offset + to_read > dev->leb_size)
to_read = dev->leb_size - offset;
ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
if (ret < 0)
return ret;
bytes_left -= to_read;
to_read = bytes_left;
leb += 1;
offset = 0;
}
return 0;
}
static int ubiblock_open(struct block_device *bdev, fmode_t mode)
{
struct ubiblock *dev = bdev->bd_disk->private_data;
int ret;
mutex_lock(&dev->dev_mutex);
if (dev->refcnt > 0) {
/*
* The volume is already open, just increase the reference
* counter.
*/
goto out_done;
}
/*
* We want users to be aware they should only mount us as read-only.
* It's just a paranoid check, as write requests will get rejected
* in any case.
*/
if (mode & FMODE_WRITE) {
ret = -EPERM;
goto out_unlock;
}
dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
if (IS_ERR(dev->desc)) {
dev_err(disk_to_dev(dev->gd), "failed to open ubi volume %d_%d",
dev->ubi_num, dev->vol_id);
ret = PTR_ERR(dev->desc);
dev->desc = NULL;
goto out_unlock;
}
out_done:
dev->refcnt++;
mutex_unlock(&dev->dev_mutex);
return 0;
out_unlock:
mutex_unlock(&dev->dev_mutex);
return ret;
}
static void ubiblock_release(struct gendisk *gd, fmode_t mode)
{
struct ubiblock *dev = gd->private_data;
mutex_lock(&dev->dev_mutex);
dev->refcnt--;
if (dev->refcnt == 0) {
ubi_close_volume(dev->desc);
dev->desc = NULL;
}
mutex_unlock(&dev->dev_mutex);
}
static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
/* Some tools might require this information */
geo->heads = 1;
geo->cylinders = 1;
geo->sectors = get_capacity(bdev->bd_disk);
geo->start = 0;
return 0;
}
static const struct block_device_operations ubiblock_ops = {
.owner = THIS_MODULE,
.open = ubiblock_open,
.release = ubiblock_release,
.getgeo = ubiblock_getgeo,
};
static void ubiblock_do_work(struct work_struct *work)
{
int ret;
struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
struct request *req = blk_mq_rq_from_pdu(pdu);
blk_mq_start_request(req);
blk_rq_map_sg(req->q, req, pdu->usgl.sg);
ret = ubiblock_read(pdu);
blk_mq_end_request(req, ret);
}
static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct request *req = bd->rq;
struct ubiblock *dev = hctx->queue->queuedata;
struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
if (req->cmd_type != REQ_TYPE_FS)
return BLK_MQ_RQ_QUEUE_ERROR;
if (rq_data_dir(req) != READ)
return BLK_MQ_RQ_QUEUE_ERROR; /* Write not implemented */
ubi_sgl_init(&pdu->usgl);
queue_work(dev->wq, &pdu->work);
return BLK_MQ_RQ_QUEUE_OK;
}
static int ubiblock_init_request(void *data, struct request *req,
unsigned int hctx_idx,
unsigned int request_idx,
unsigned int numa_node)
{
struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
INIT_WORK(&pdu->work, ubiblock_do_work);
return 0;
}
static struct blk_mq_ops ubiblock_mq_ops = {
.queue_rq = ubiblock_queue_rq,
.init_request = ubiblock_init_request,
.map_queue = blk_mq_map_queue,
};
int ubiblock_create(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
struct gendisk *gd;
u64 disk_capacity = vi->used_bytes >> 9;
int ret;
if ((sector_t)disk_capacity != disk_capacity)
return -EFBIG;
/* Check that the volume isn't already handled */
mutex_lock(&devices_mutex);
if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
mutex_unlock(&devices_mutex);
return -EEXIST;
}
mutex_unlock(&devices_mutex);
dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
if (!dev)
return -ENOMEM;
mutex_init(&dev->dev_mutex);
dev->ubi_num = vi->ubi_num;
dev->vol_id = vi->vol_id;
dev->leb_size = vi->usable_leb_size;
/* Initialize the gendisk of this ubiblock device */
gd = alloc_disk(1);
if (!gd) {
pr_err("UBI: block: alloc_disk failed");
ret = -ENODEV;
goto out_free_dev;
}
gd->fops = &ubiblock_ops;
gd->major = ubiblock_major;
gd->first_minor = dev->ubi_num * UBI_MAX_VOLUMES + dev->vol_id;
gd->private_data = dev;
sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
set_capacity(gd, disk_capacity);
dev->gd = gd;
dev->tag_set.ops = &ubiblock_mq_ops;
dev->tag_set.queue_depth = 64;
dev->tag_set.numa_node = NUMA_NO_NODE;
dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
dev->tag_set.driver_data = dev;
dev->tag_set.nr_hw_queues = 1;
ret = blk_mq_alloc_tag_set(&dev->tag_set);
if (ret) {
dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
goto out_put_disk;
}
dev->rq = blk_mq_init_queue(&dev->tag_set);
if (!dev->rq) {
dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
ret = -ENODEV;
goto out_free_tags;
}
blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
dev->rq->queuedata = dev;
dev->gd->queue = dev->rq;
/*
* Create one workqueue per volume (per registered block device).
* Rembember workqueues are cheap, they're not threads.
*/
dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
if (!dev->wq) {
ret = -ENOMEM;
goto out_free_queue;
}
mutex_lock(&devices_mutex);
list_add_tail(&dev->list, &ubiblock_devices);
mutex_unlock(&devices_mutex);
/* Must be the last step: anyone can call file ops from now on */
add_disk(dev->gd);
dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
dev->ubi_num, dev->vol_id, vi->name);
return 0;
out_free_queue:
blk_cleanup_queue(dev->rq);
out_free_tags:
blk_mq_free_tag_set(&dev->tag_set);
out_put_disk:
put_disk(dev->gd);
out_free_dev:
kfree(dev);
return ret;
}
static void ubiblock_cleanup(struct ubiblock *dev)
{
/* Stop new requests to arrive */
del_gendisk(dev->gd);
/* Flush pending work */
destroy_workqueue(dev->wq);
/* Finally destroy the blk queue */
blk_cleanup_queue(dev->rq);
blk_mq_free_tag_set(&dev->tag_set);
dev_info(disk_to_dev(dev->gd), "released");
put_disk(dev->gd);
}
int ubiblock_remove(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
mutex_lock(&devices_mutex);
dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
if (!dev) {
mutex_unlock(&devices_mutex);
return -ENODEV;
}
/* Found a device, let's lock it so we can check if it's busy */
mutex_lock(&dev->dev_mutex);
if (dev->refcnt > 0) {
mutex_unlock(&dev->dev_mutex);
mutex_unlock(&devices_mutex);
return -EBUSY;
}
/* Remove from device list */
list_del(&dev->list);
mutex_unlock(&devices_mutex);
ubiblock_cleanup(dev);
mutex_unlock(&dev->dev_mutex);
kfree(dev);
return 0;
}
static int ubiblock_resize(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
u64 disk_capacity = vi->used_bytes >> 9;
/*
* Need to lock the device list until we stop using the device,
* otherwise the device struct might get released in
* 'ubiblock_remove()'.
*/
mutex_lock(&devices_mutex);
dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
if (!dev) {
mutex_unlock(&devices_mutex);
return -ENODEV;
}
if ((sector_t)disk_capacity != disk_capacity) {
mutex_unlock(&devices_mutex);
dev_warn(disk_to_dev(dev->gd), "the volume is too big (%d LEBs), cannot resize",
vi->size);
return -EFBIG;
}
mutex_lock(&dev->dev_mutex);
if (get_capacity(dev->gd) != disk_capacity) {
set_capacity(dev->gd, disk_capacity);
dev_info(disk_to_dev(dev->gd), "resized to %lld bytes",
vi->used_bytes);
}
mutex_unlock(&dev->dev_mutex);
mutex_unlock(&devices_mutex);
return 0;
}
static int ubiblock_notify(struct notifier_block *nb,
unsigned long notification_type, void *ns_ptr)
{
struct ubi_notification *nt = ns_ptr;
switch (notification_type) {
case UBI_VOLUME_ADDED:
/*
* We want to enforce explicit block device creation for
* volumes, so when a volume is added we do nothing.
*/
break;
case UBI_VOLUME_REMOVED:
ubiblock_remove(&nt->vi);
break;
case UBI_VOLUME_RESIZED:
ubiblock_resize(&nt->vi);
break;
case UBI_VOLUME_UPDATED:
/*
* If the volume is static, a content update might mean the
* size (i.e. used_bytes) was also changed.
*/
if (nt->vi.vol_type == UBI_STATIC_VOLUME)
ubiblock_resize(&nt->vi);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block ubiblock_notifier = {
.notifier_call = ubiblock_notify,
};
static struct ubi_volume_desc * __init
open_volume_desc(const char *name, int ubi_num, int vol_id)
{
if (ubi_num == -1)
/* No ubi num, name must be a vol device path */
return ubi_open_volume_path(name, UBI_READONLY);
else if (vol_id == -1)
/* No vol_id, must be vol_name */
return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
else
return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
}
static int __init ubiblock_create_from_param(void)
{
int i, ret;
struct ubiblock_param *p;
struct ubi_volume_desc *desc;
struct ubi_volume_info vi;
for (i = 0; i < ubiblock_devs; i++) {
p = &ubiblock_param[i];
desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
if (IS_ERR(desc)) {
pr_err("UBI: block: can't open volume, err=%ld\n",
PTR_ERR(desc));
ret = PTR_ERR(desc);
break;
}
ubi_get_volume_info(desc, &vi);
ubi_close_volume(desc);
ret = ubiblock_create(&vi);
if (ret) {
pr_err("UBI: block: can't add '%s' volume, err=%d\n",
vi.name, ret);
break;
}
}
return ret;
}
static void ubiblock_remove_all(void)
{
struct ubiblock *next;
struct ubiblock *dev;
list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
/* The module is being forcefully removed */
WARN_ON(dev->desc);
/* Remove from device list */
list_del(&dev->list);
ubiblock_cleanup(dev);
kfree(dev);
}
}
int __init ubiblock_init(void)
{
int ret;
ubiblock_major = register_blkdev(0, "ubiblock");
if (ubiblock_major < 0)
return ubiblock_major;
/* Attach block devices from 'block=' module param */
ret = ubiblock_create_from_param();
if (ret)
goto err_remove;
/*
* Block devices are only created upon user requests, so we ignore
* existing volumes.
*/
ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
if (ret)
goto err_unreg;
return 0;
err_unreg:
unregister_blkdev(ubiblock_major, "ubiblock");
err_remove:
ubiblock_remove_all();
return ret;
}
void __exit ubiblock_exit(void)
{
ubi_unregister_volume_notifier(&ubiblock_notifier);
ubiblock_remove_all();
unregister_blkdev(ubiblock_major, "ubiblock");
}
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