linux/drivers/mtd/ubi/block.c
Richard Weinberger e46131b9fd ubi: block: Warn if volume size is not multiple of 512
If volume size is not a multiple of 512, ubi block cuts
off the last bytes of an volume since the block layer works
on 512 byte sectors.
This can happen especially on NOR flash with minimal io
size of 1.

To avoid unpleasant surprises, print a warning.

Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15 22:12:49 +02:00

708 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
*/
/*
* 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 <linux/idr.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_IDR(ubiblock_minor_idr);
/* Protects ubiblock_devices and ubiblock_minor_idr */
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, &param->ubi_num);
if (ret < 0)
return -EINVAL;
/* Second param can be a number or a name */
ret = kstrtoint(tokens[1], 10, &param->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 const 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 = -EROFS;
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);
/*
* It is safe to ignore the return value of blk_rq_map_sg() because
* the number of sg entries is limited to UBI_MAX_SG_COUNT
* and ubi_read_sg() will check that limit.
*/
blk_rq_map_sg(req->q, req, pdu->usgl.sg);
ret = ubiblock_read(pdu);
rq_flush_dcache_pages(req);
blk_mq_end_request(req, errno_to_blk_status(ret));
}
static blk_status_t 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);
switch (req_op(req)) {
case REQ_OP_READ:
ubi_sgl_init(&pdu->usgl);
queue_work(dev->wq, &pdu->work);
return BLK_STS_OK;
default:
return BLK_STS_IOERR;
}
}
static int ubiblock_init_request(struct blk_mq_tag_set *set,
struct request *req, unsigned int hctx_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 const struct blk_mq_ops ubiblock_mq_ops = {
.queue_rq = ubiblock_queue_rq,
.init_request = ubiblock_init_request,
};
static int calc_disk_capacity(struct ubi_volume_info *vi, u64 *disk_capacity)
{
u64 size = vi->used_bytes >> 9;
if (vi->used_bytes % 512) {
pr_warn("UBI: block: volume size is not a multiple of 512, "
"last %llu bytes are ignored!\n",
vi->used_bytes - (size << 9));
}
if ((sector_t)size != size)
return -EFBIG;
*disk_capacity = size;
return 0;
}
int ubiblock_create(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
struct gendisk *gd;
u64 disk_capacity;
int ret;
ret = calc_disk_capacity(vi, &disk_capacity);
if (ret) {
return ret;
}
/* Check that the volume isn't already handled */
mutex_lock(&devices_mutex);
if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
ret = -EEXIST;
goto out_unlock;
}
dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
if (!dev) {
ret = -ENOMEM;
goto out_unlock;
}
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\n");
ret = -ENODEV;
goto out_free_dev;
}
gd->fops = &ubiblock_ops;
gd->major = ubiblock_major;
gd->first_minor = idr_alloc(&ubiblock_minor_idr, dev, 0, 0, GFP_KERNEL);
if (gd->first_minor < 0) {
dev_err(disk_to_dev(gd),
"block: dynamic minor allocation failed");
ret = -ENODEV;
goto out_put_disk;
}
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_remove_minor;
}
dev->rq = blk_mq_init_queue(&dev->tag_set);
if (IS_ERR(dev->rq)) {
dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
ret = PTR_ERR(dev->rq);
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;
}
list_add_tail(&dev->list, &ubiblock_devices);
/* 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);
mutex_unlock(&devices_mutex);
return 0;
out_free_queue:
blk_cleanup_queue(dev->rq);
out_free_tags:
blk_mq_free_tag_set(&dev->tag_set);
out_remove_minor:
idr_remove(&ubiblock_minor_idr, gd->first_minor);
out_put_disk:
put_disk(dev->gd);
out_free_dev:
kfree(dev);
out_unlock:
mutex_unlock(&devices_mutex);
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");
idr_remove(&ubiblock_minor_idr, dev->gd->first_minor);
put_disk(dev->gd);
}
int ubiblock_remove(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
int ret;
mutex_lock(&devices_mutex);
dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
if (!dev) {
ret = -ENODEV;
goto out_unlock;
}
/* Found a device, let's lock it so we can check if it's busy */
mutex_lock(&dev->dev_mutex);
if (dev->refcnt > 0) {
ret = -EBUSY;
goto out_unlock_dev;
}
/* Remove from device list */
list_del(&dev->list);
ubiblock_cleanup(dev);
mutex_unlock(&dev->dev_mutex);
mutex_unlock(&devices_mutex);
kfree(dev);
return 0;
out_unlock_dev:
mutex_unlock(&dev->dev_mutex);
out_unlock:
mutex_unlock(&devices_mutex);
return ret;
}
static int ubiblock_resize(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
u64 disk_capacity;
int ret;
/*
* 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;
}
ret = calc_disk_capacity(vi, &disk_capacity);
if (ret) {
mutex_unlock(&devices_mutex);
if (ret == -EFBIG) {
dev_warn(disk_to_dev(dev->gd),
"the volume is too big (%d LEBs), cannot resize",
vi->size);
}
return ret;
}
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 void __init ubiblock_create_from_param(void)
{
int i, ret = 0;
struct ubiblock_param *p;
struct ubi_volume_desc *desc;
struct ubi_volume_info vi;
/*
* If there is an error creating one of the ubiblocks, continue on to
* create the following ubiblocks. This helps in a circumstance where
* the kernel command-line specifies multiple block devices and some
* may be broken, but we still want the working ones to come up.
*/
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 on ubi%d_%d, err=%ld\n",
p->ubi_num, p->vol_id, PTR_ERR(desc));
continue;
}
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 on ubi%d_%d, err=%d\n",
vi.name, p->ubi_num, p->vol_id, ret);
continue;
}
}
}
static void ubiblock_remove_all(void)
{
struct ubiblock *next;
struct ubiblock *dev;
mutex_lock(&devices_mutex);
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);
}
mutex_unlock(&devices_mutex);
}
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.
* Even if one block device in the param list fails to come up,
* still allow the module to load and leave any others up.
*/
ubiblock_create_from_param();
/*
* 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");
ubiblock_remove_all();
return ret;
}
void __exit ubiblock_exit(void)
{
ubi_unregister_volume_notifier(&ubiblock_notifier);
ubiblock_remove_all();
unregister_blkdev(ubiblock_major, "ubiblock");
}