linux/drivers/mtd/ubi/gluebi.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
Based on 1 normalized pattern(s):

  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 either version 2 of the license or at
  your option any later version 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 you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

501 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) International Business Machines Corp., 2006
*
* Author: Artem Bityutskiy (Битюцкий Артём), Joern Engel
*/
/*
* This is a small driver which implements fake MTD devices on top of UBI
* volumes. This sounds strange, but it is in fact quite useful to make
* MTD-oriented software (including all the legacy software) work on top of
* UBI.
*
* Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
* size (@mtd->writesize) is equivalent to the UBI minimal I/O unit. The
* eraseblock size is equivalent to the logical eraseblock size of the volume.
*/
#include <linux/err.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/mtd/ubi.h>
#include <linux/mtd/mtd.h>
#include "ubi-media.h"
#define err_msg(fmt, ...) \
pr_err("gluebi (pid %d): %s: " fmt "\n", \
current->pid, __func__, ##__VA_ARGS__)
/**
* struct gluebi_device - a gluebi device description data structure.
* @mtd: emulated MTD device description object
* @refcnt: gluebi device reference count
* @desc: UBI volume descriptor
* @ubi_num: UBI device number this gluebi device works on
* @vol_id: ID of UBI volume this gluebi device works on
* @list: link in a list of gluebi devices
*/
struct gluebi_device {
struct mtd_info mtd;
int refcnt;
struct ubi_volume_desc *desc;
int ubi_num;
int vol_id;
struct list_head list;
};
/* List of all gluebi devices */
static LIST_HEAD(gluebi_devices);
static DEFINE_MUTEX(devices_mutex);
/**
* find_gluebi_nolock - find a gluebi device.
* @ubi_num: UBI device number
* @vol_id: volume ID
*
* This function seraches for gluebi device corresponding to UBI device
* @ubi_num and UBI volume @vol_id. Returns the gluebi device description
* object in case of success and %NULL in case of failure. The caller has to
* have the &devices_mutex locked.
*/
static struct gluebi_device *find_gluebi_nolock(int ubi_num, int vol_id)
{
struct gluebi_device *gluebi;
list_for_each_entry(gluebi, &gluebi_devices, list)
if (gluebi->ubi_num == ubi_num && gluebi->vol_id == vol_id)
return gluebi;
return NULL;
}
/**
* gluebi_get_device - get MTD device reference.
* @mtd: the MTD device description object
*
* This function is called every time the MTD device is being opened and
* implements the MTD get_device() operation. Returns zero in case of success
* and a negative error code in case of failure.
*/
static int gluebi_get_device(struct mtd_info *mtd)
{
struct gluebi_device *gluebi;
int ubi_mode = UBI_READONLY;
if (mtd->flags & MTD_WRITEABLE)
ubi_mode = UBI_READWRITE;
gluebi = container_of(mtd, struct gluebi_device, mtd);
mutex_lock(&devices_mutex);
if (gluebi->refcnt > 0) {
/*
* The MTD device is already referenced and this is just one
* more reference. MTD allows many users to open the same
* volume simultaneously and do not distinguish between
* readers/writers/exclusive/meta openers as UBI does. So we do
* not open the UBI volume again - just increase the reference
* counter and return.
*/
gluebi->refcnt += 1;
mutex_unlock(&devices_mutex);
return 0;
}
/*
* This is the first reference to this UBI volume via the MTD device
* interface. Open the corresponding volume in read-write mode.
*/
gluebi->desc = ubi_open_volume(gluebi->ubi_num, gluebi->vol_id,
ubi_mode);
if (IS_ERR(gluebi->desc)) {
mutex_unlock(&devices_mutex);
return PTR_ERR(gluebi->desc);
}
gluebi->refcnt += 1;
mutex_unlock(&devices_mutex);
return 0;
}
/**
* gluebi_put_device - put MTD device reference.
* @mtd: the MTD device description object
*
* This function is called every time the MTD device is being put. Returns
* zero in case of success and a negative error code in case of failure.
*/
static void gluebi_put_device(struct mtd_info *mtd)
{
struct gluebi_device *gluebi;
gluebi = container_of(mtd, struct gluebi_device, mtd);
mutex_lock(&devices_mutex);
gluebi->refcnt -= 1;
if (gluebi->refcnt == 0)
ubi_close_volume(gluebi->desc);
mutex_unlock(&devices_mutex);
}
/**
* gluebi_read - read operation of emulated MTD devices.
* @mtd: MTD device description object
* @from: absolute offset from where to read
* @len: how many bytes to read
* @retlen: count of read bytes is returned here
* @buf: buffer to store the read data
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, unsigned char *buf)
{
int err = 0, lnum, offs, bytes_left;
struct gluebi_device *gluebi;
gluebi = container_of(mtd, struct gluebi_device, mtd);
lnum = div_u64_rem(from, mtd->erasesize, &offs);
bytes_left = len;
while (bytes_left) {
size_t to_read = mtd->erasesize - offs;
if (to_read > bytes_left)
to_read = bytes_left;
err = ubi_read(gluebi->desc, lnum, buf, offs, to_read);
if (err)
break;
lnum += 1;
offs = 0;
bytes_left -= to_read;
buf += to_read;
}
*retlen = len - bytes_left;
return err;
}
/**
* gluebi_write - write operation of emulated MTD devices.
* @mtd: MTD device description object
* @to: absolute offset where to write
* @len: how many bytes to write
* @retlen: count of written bytes is returned here
* @buf: buffer with data to write
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
int err = 0, lnum, offs, bytes_left;
struct gluebi_device *gluebi;
gluebi = container_of(mtd, struct gluebi_device, mtd);
lnum = div_u64_rem(to, mtd->erasesize, &offs);
if (len % mtd->writesize || offs % mtd->writesize)
return -EINVAL;
bytes_left = len;
while (bytes_left) {
size_t to_write = mtd->erasesize - offs;
if (to_write > bytes_left)
to_write = bytes_left;
err = ubi_leb_write(gluebi->desc, lnum, buf, offs, to_write);
if (err)
break;
lnum += 1;
offs = 0;
bytes_left -= to_write;
buf += to_write;
}
*retlen = len - bytes_left;
return err;
}
/**
* gluebi_erase - erase operation of emulated MTD devices.
* @mtd: the MTD device description object
* @instr: the erase operation description
*
* This function calls the erase callback when finishes. Returns zero in case
* of success and a negative error code in case of failure.
*/
static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
{
int err, i, lnum, count;
struct gluebi_device *gluebi;
if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd))
return -EINVAL;
lnum = mtd_div_by_eb(instr->addr, mtd);
count = mtd_div_by_eb(instr->len, mtd);
gluebi = container_of(mtd, struct gluebi_device, mtd);
for (i = 0; i < count - 1; i++) {
err = ubi_leb_unmap(gluebi->desc, lnum + i);
if (err)
goto out_err;
}
/*
* MTD erase operations are synchronous, so we have to make sure the
* physical eraseblock is wiped out.
*
* Thus, perform leb_erase instead of leb_unmap operation - leb_erase
* will wait for the end of operations
*/
err = ubi_leb_erase(gluebi->desc, lnum + i);
if (err)
goto out_err;
return 0;
out_err:
instr->fail_addr = (long long)lnum * mtd->erasesize;
return err;
}
/**
* gluebi_create - create a gluebi device for an UBI volume.
* @di: UBI device description object
* @vi: UBI volume description object
*
* This function is called when a new UBI volume is created in order to create
* corresponding fake MTD device. Returns zero in case of success and a
* negative error code in case of failure.
*/
static int gluebi_create(struct ubi_device_info *di,
struct ubi_volume_info *vi)
{
struct gluebi_device *gluebi, *g;
struct mtd_info *mtd;
gluebi = kzalloc(sizeof(struct gluebi_device), GFP_KERNEL);
if (!gluebi)
return -ENOMEM;
mtd = &gluebi->mtd;
mtd->name = kmemdup(vi->name, vi->name_len + 1, GFP_KERNEL);
if (!mtd->name) {
kfree(gluebi);
return -ENOMEM;
}
gluebi->vol_id = vi->vol_id;
gluebi->ubi_num = vi->ubi_num;
mtd->type = MTD_UBIVOLUME;
if (!di->ro_mode)
mtd->flags = MTD_WRITEABLE;
mtd->owner = THIS_MODULE;
mtd->writesize = di->min_io_size;
mtd->erasesize = vi->usable_leb_size;
mtd->_read = gluebi_read;
mtd->_write = gluebi_write;
mtd->_erase = gluebi_erase;
mtd->_get_device = gluebi_get_device;
mtd->_put_device = gluebi_put_device;
/*
* In case of dynamic a volume, MTD device size is just volume size. In
* case of a static volume the size is equivalent to the amount of data
* bytes.
*/
if (vi->vol_type == UBI_DYNAMIC_VOLUME)
mtd->size = (unsigned long long)vi->usable_leb_size * vi->size;
else
mtd->size = vi->used_bytes;
/* Just a sanity check - make sure this gluebi device does not exist */
mutex_lock(&devices_mutex);
g = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
if (g)
err_msg("gluebi MTD device %d form UBI device %d volume %d already exists",
g->mtd.index, vi->ubi_num, vi->vol_id);
mutex_unlock(&devices_mutex);
if (mtd_device_register(mtd, NULL, 0)) {
err_msg("cannot add MTD device");
kfree(mtd->name);
kfree(gluebi);
return -ENFILE;
}
mutex_lock(&devices_mutex);
list_add_tail(&gluebi->list, &gluebi_devices);
mutex_unlock(&devices_mutex);
return 0;
}
/**
* gluebi_remove - remove a gluebi device.
* @vi: UBI volume description object
*
* This function is called when an UBI volume is removed and it removes
* corresponding fake MTD device. Returns zero in case of success and a
* negative error code in case of failure.
*/
static int gluebi_remove(struct ubi_volume_info *vi)
{
int err = 0;
struct mtd_info *mtd;
struct gluebi_device *gluebi;
mutex_lock(&devices_mutex);
gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
if (!gluebi) {
err_msg("got remove notification for unknown UBI device %d volume %d",
vi->ubi_num, vi->vol_id);
err = -ENOENT;
} else if (gluebi->refcnt)
err = -EBUSY;
else
list_del(&gluebi->list);
mutex_unlock(&devices_mutex);
if (err)
return err;
mtd = &gluebi->mtd;
err = mtd_device_unregister(mtd);
if (err) {
err_msg("cannot remove fake MTD device %d, UBI device %d, volume %d, error %d",
mtd->index, gluebi->ubi_num, gluebi->vol_id, err);
mutex_lock(&devices_mutex);
list_add_tail(&gluebi->list, &gluebi_devices);
mutex_unlock(&devices_mutex);
return err;
}
kfree(mtd->name);
kfree(gluebi);
return 0;
}
/**
* gluebi_updated - UBI volume was updated notifier.
* @vi: volume info structure
*
* This function is called every time an UBI volume is updated. It does nothing
* if te volume @vol is dynamic, and changes MTD device size if the
* volume is static. This is needed because static volumes cannot be read past
* data they contain. This function returns zero in case of success and a
* negative error code in case of error.
*/
static int gluebi_updated(struct ubi_volume_info *vi)
{
struct gluebi_device *gluebi;
mutex_lock(&devices_mutex);
gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
if (!gluebi) {
mutex_unlock(&devices_mutex);
err_msg("got update notification for unknown UBI device %d volume %d",
vi->ubi_num, vi->vol_id);
return -ENOENT;
}
if (vi->vol_type == UBI_STATIC_VOLUME)
gluebi->mtd.size = vi->used_bytes;
mutex_unlock(&devices_mutex);
return 0;
}
/**
* gluebi_resized - UBI volume was re-sized notifier.
* @vi: volume info structure
*
* This function is called every time an UBI volume is re-size. It changes the
* corresponding fake MTD device size. This function returns zero in case of
* success and a negative error code in case of error.
*/
static int gluebi_resized(struct ubi_volume_info *vi)
{
struct gluebi_device *gluebi;
mutex_lock(&devices_mutex);
gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
if (!gluebi) {
mutex_unlock(&devices_mutex);
err_msg("got update notification for unknown UBI device %d volume %d",
vi->ubi_num, vi->vol_id);
return -ENOENT;
}
gluebi->mtd.size = vi->used_bytes;
mutex_unlock(&devices_mutex);
return 0;
}
/**
* gluebi_notify - UBI notification handler.
* @nb: registered notifier block
* @l: notification type
* @ptr: pointer to the &struct ubi_notification object
*/
static int gluebi_notify(struct notifier_block *nb, unsigned long l,
void *ns_ptr)
{
struct ubi_notification *nt = ns_ptr;
switch (l) {
case UBI_VOLUME_ADDED:
gluebi_create(&nt->di, &nt->vi);
break;
case UBI_VOLUME_REMOVED:
gluebi_remove(&nt->vi);
break;
case UBI_VOLUME_RESIZED:
gluebi_resized(&nt->vi);
break;
case UBI_VOLUME_UPDATED:
gluebi_updated(&nt->vi);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block gluebi_notifier = {
.notifier_call = gluebi_notify,
};
static int __init ubi_gluebi_init(void)
{
return ubi_register_volume_notifier(&gluebi_notifier, 0);
}
static void __exit ubi_gluebi_exit(void)
{
struct gluebi_device *gluebi, *g;
list_for_each_entry_safe(gluebi, g, &gluebi_devices, list) {
int err;
struct mtd_info *mtd = &gluebi->mtd;
err = mtd_device_unregister(mtd);
if (err)
err_msg("error %d while removing gluebi MTD device %d, UBI device %d, volume %d - ignoring",
err, mtd->index, gluebi->ubi_num,
gluebi->vol_id);
kfree(mtd->name);
kfree(gluebi);
}
ubi_unregister_volume_notifier(&gluebi_notifier);
}
module_init(ubi_gluebi_init);
module_exit(ubi_gluebi_exit);
MODULE_DESCRIPTION("MTD emulation layer over UBI volumes");
MODULE_AUTHOR("Artem Bityutskiy, Joern Engel");
MODULE_LICENSE("GPL");