linux/drivers/mtd/ubi/gluebi.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

543 lines
15 KiB
C

/*
* Copyright (c) International Business Machines Corp., 2006
*
* 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
*
* 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, ...) \
printk(KERN_DEBUG "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 (!try_module_get(THIS_MODULE))
return -ENODEV;
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 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);
module_put(THIS_MODULE);
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);
module_put(THIS_MODULE);
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, total_read;
struct gluebi_device *gluebi;
if (len < 0 || from < 0 || from + len > mtd->size)
return -EINVAL;
gluebi = container_of(mtd, struct gluebi_device, mtd);
lnum = div_u64_rem(from, mtd->erasesize, &offs);
total_read = len;
while (total_read) {
size_t to_read = mtd->erasesize - offs;
if (to_read > total_read)
to_read = total_read;
err = ubi_read(gluebi->desc, lnum, buf, offs, to_read);
if (err)
break;
lnum += 1;
offs = 0;
total_read -= to_read;
buf += to_read;
}
*retlen = len - total_read;
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, total_written;
struct gluebi_device *gluebi;
if (len < 0 || to < 0 || len + to > mtd->size)
return -EINVAL;
gluebi = container_of(mtd, struct gluebi_device, mtd);
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
lnum = div_u64_rem(to, mtd->erasesize, &offs);
if (len % mtd->writesize || offs % mtd->writesize)
return -EINVAL;
total_written = len;
while (total_written) {
size_t to_write = mtd->erasesize - offs;
if (to_write > total_written)
to_write = total_written;
err = ubi_write(gluebi->desc, lnum, buf, offs, to_write);
if (err)
break;
lnum += 1;
offs = 0;
total_written -= to_write;
buf += to_write;
}
*retlen = len - total_written;
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 (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
return -EINVAL;
if (instr->len < 0 || instr->addr + instr->len > mtd->size)
return -EINVAL;
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);
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
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;
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
out_err:
instr->state = MTD_ERASE_FAILED;
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 (add_mtd_device(mtd)) {
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 = del_mtd_device(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 = del_mtd_device(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");