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linux-next/drivers/acpi/ac.c
Alexey Dobriyan 99b7623380 proc 2/2: remove struct proc_dir_entry::owner
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.

We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.

But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.

->read_proc/->write_proc were just fixed to not require ->owner for
protection.

rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.

Removing ->owner will also make PDE smaller.

So, let's nuke it.

Kudos to Jeff Layton for reminding about this, let's say, oversight.

http://bugzilla.kernel.org/show_bug.cgi?id=12454

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31 01:14:44 +04:00

393 lines
9.2 KiB
C

/*
* acpi_ac.c - ACPI AC Adapter Driver ($Revision: 27 $)
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#ifdef CONFIG_ACPI_PROCFS_POWER
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#endif
#ifdef CONFIG_ACPI_SYSFS_POWER
#include <linux/power_supply.h>
#endif
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#define ACPI_AC_CLASS "ac_adapter"
#define ACPI_AC_DEVICE_NAME "AC Adapter"
#define ACPI_AC_FILE_STATE "state"
#define ACPI_AC_NOTIFY_STATUS 0x80
#define ACPI_AC_STATUS_OFFLINE 0x00
#define ACPI_AC_STATUS_ONLINE 0x01
#define ACPI_AC_STATUS_UNKNOWN 0xFF
#define _COMPONENT ACPI_AC_COMPONENT
ACPI_MODULE_NAME("ac");
MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI AC Adapter Driver");
MODULE_LICENSE("GPL");
#ifdef CONFIG_ACPI_PROCFS_POWER
extern struct proc_dir_entry *acpi_lock_ac_dir(void);
extern void *acpi_unlock_ac_dir(struct proc_dir_entry *acpi_ac_dir);
static int acpi_ac_open_fs(struct inode *inode, struct file *file);
#endif
static int acpi_ac_add(struct acpi_device *device);
static int acpi_ac_remove(struct acpi_device *device, int type);
static int acpi_ac_resume(struct acpi_device *device);
static const struct acpi_device_id ac_device_ids[] = {
{"ACPI0003", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, ac_device_ids);
static struct acpi_driver acpi_ac_driver = {
.name = "ac",
.class = ACPI_AC_CLASS,
.ids = ac_device_ids,
.ops = {
.add = acpi_ac_add,
.remove = acpi_ac_remove,
.resume = acpi_ac_resume,
},
};
struct acpi_ac {
#ifdef CONFIG_ACPI_SYSFS_POWER
struct power_supply charger;
#endif
struct acpi_device * device;
unsigned long long state;
};
#define to_acpi_ac(x) container_of(x, struct acpi_ac, charger);
#ifdef CONFIG_ACPI_PROCFS_POWER
static const struct file_operations acpi_ac_fops = {
.owner = THIS_MODULE,
.open = acpi_ac_open_fs,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif
#ifdef CONFIG_ACPI_SYSFS_POWER
static int get_ac_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct acpi_ac *ac = to_acpi_ac(psy);
switch (psp) {
case POWER_SUPPLY_PROP_ONLINE:
val->intval = ac->state;
break;
default:
return -EINVAL;
}
return 0;
}
static enum power_supply_property ac_props[] = {
POWER_SUPPLY_PROP_ONLINE,
};
#endif
/* --------------------------------------------------------------------------
AC Adapter Management
-------------------------------------------------------------------------- */
static int acpi_ac_get_state(struct acpi_ac *ac)
{
acpi_status status = AE_OK;
if (!ac)
return -EINVAL;
status = acpi_evaluate_integer(ac->device->handle, "_PSR", NULL, &ac->state);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Error reading AC Adapter state"));
ac->state = ACPI_AC_STATUS_UNKNOWN;
return -ENODEV;
}
return 0;
}
#ifdef CONFIG_ACPI_PROCFS_POWER
/* --------------------------------------------------------------------------
FS Interface (/proc)
-------------------------------------------------------------------------- */
static struct proc_dir_entry *acpi_ac_dir;
static int acpi_ac_seq_show(struct seq_file *seq, void *offset)
{
struct acpi_ac *ac = seq->private;
if (!ac)
return 0;
if (acpi_ac_get_state(ac)) {
seq_puts(seq, "ERROR: Unable to read AC Adapter state\n");
return 0;
}
seq_puts(seq, "state: ");
switch (ac->state) {
case ACPI_AC_STATUS_OFFLINE:
seq_puts(seq, "off-line\n");
break;
case ACPI_AC_STATUS_ONLINE:
seq_puts(seq, "on-line\n");
break;
default:
seq_puts(seq, "unknown\n");
break;
}
return 0;
}
static int acpi_ac_open_fs(struct inode *inode, struct file *file)
{
return single_open(file, acpi_ac_seq_show, PDE(inode)->data);
}
static int acpi_ac_add_fs(struct acpi_device *device)
{
struct proc_dir_entry *entry = NULL;
if (!acpi_device_dir(device)) {
acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
acpi_ac_dir);
if (!acpi_device_dir(device))
return -ENODEV;
}
/* 'state' [R] */
entry = proc_create_data(ACPI_AC_FILE_STATE,
S_IRUGO, acpi_device_dir(device),
&acpi_ac_fops, acpi_driver_data(device));
if (!entry)
return -ENODEV;
return 0;
}
static int acpi_ac_remove_fs(struct acpi_device *device)
{
if (acpi_device_dir(device)) {
remove_proc_entry(ACPI_AC_FILE_STATE, acpi_device_dir(device));
remove_proc_entry(acpi_device_bid(device), acpi_ac_dir);
acpi_device_dir(device) = NULL;
}
return 0;
}
#endif
/* --------------------------------------------------------------------------
Driver Model
-------------------------------------------------------------------------- */
static void acpi_ac_notify(acpi_handle handle, u32 event, void *data)
{
struct acpi_ac *ac = data;
struct acpi_device *device = NULL;
if (!ac)
return;
device = ac->device;
switch (event) {
default:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Unsupported event [0x%x]\n", event));
case ACPI_AC_NOTIFY_STATUS:
case ACPI_NOTIFY_BUS_CHECK:
case ACPI_NOTIFY_DEVICE_CHECK:
acpi_ac_get_state(ac);
acpi_bus_generate_proc_event(device, event, (u32) ac->state);
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event,
(u32) ac->state);
#ifdef CONFIG_ACPI_SYSFS_POWER
kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
#endif
}
return;
}
static int acpi_ac_add(struct acpi_device *device)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_ac *ac = NULL;
if (!device)
return -EINVAL;
ac = kzalloc(sizeof(struct acpi_ac), GFP_KERNEL);
if (!ac)
return -ENOMEM;
ac->device = device;
strcpy(acpi_device_name(device), ACPI_AC_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_AC_CLASS);
device->driver_data = ac;
result = acpi_ac_get_state(ac);
if (result)
goto end;
#ifdef CONFIG_ACPI_PROCFS_POWER
result = acpi_ac_add_fs(device);
#endif
if (result)
goto end;
#ifdef CONFIG_ACPI_SYSFS_POWER
ac->charger.name = acpi_device_bid(device);
ac->charger.type = POWER_SUPPLY_TYPE_MAINS;
ac->charger.properties = ac_props;
ac->charger.num_properties = ARRAY_SIZE(ac_props);
ac->charger.get_property = get_ac_property;
power_supply_register(&ac->device->dev, &ac->charger);
#endif
status = acpi_install_notify_handler(device->handle,
ACPI_ALL_NOTIFY, acpi_ac_notify,
ac);
if (ACPI_FAILURE(status)) {
result = -ENODEV;
goto end;
}
printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
acpi_device_name(device), acpi_device_bid(device),
ac->state ? "on-line" : "off-line");
end:
if (result) {
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_ac_remove_fs(device);
#endif
kfree(ac);
}
return result;
}
static int acpi_ac_resume(struct acpi_device *device)
{
struct acpi_ac *ac;
unsigned old_state;
if (!device || !acpi_driver_data(device))
return -EINVAL;
ac = acpi_driver_data(device);
old_state = ac->state;
if (acpi_ac_get_state(ac))
return 0;
#ifdef CONFIG_ACPI_SYSFS_POWER
if (old_state != ac->state)
kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
#endif
return 0;
}
static int acpi_ac_remove(struct acpi_device *device, int type)
{
acpi_status status = AE_OK;
struct acpi_ac *ac = NULL;
if (!device || !acpi_driver_data(device))
return -EINVAL;
ac = acpi_driver_data(device);
status = acpi_remove_notify_handler(device->handle,
ACPI_ALL_NOTIFY, acpi_ac_notify);
#ifdef CONFIG_ACPI_SYSFS_POWER
if (ac->charger.dev)
power_supply_unregister(&ac->charger);
#endif
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_ac_remove_fs(device);
#endif
kfree(ac);
return 0;
}
static int __init acpi_ac_init(void)
{
int result;
if (acpi_disabled)
return -ENODEV;
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_ac_dir = acpi_lock_ac_dir();
if (!acpi_ac_dir)
return -ENODEV;
#endif
result = acpi_bus_register_driver(&acpi_ac_driver);
if (result < 0) {
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_unlock_ac_dir(acpi_ac_dir);
#endif
return -ENODEV;
}
return 0;
}
static void __exit acpi_ac_exit(void)
{
acpi_bus_unregister_driver(&acpi_ac_driver);
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_unlock_ac_dir(acpi_ac_dir);
#endif
return;
}
module_init(acpi_ac_init);
module_exit(acpi_ac_exit);