linux/drivers/acpi/fan.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

372 lines
8.9 KiB
C

/*
* acpi_fan.c - ACPI Fan Driver ($Revision: 29 $)
*
* 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>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include <linux/thermal.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#define ACPI_FAN_CLASS "fan"
#define ACPI_FAN_FILE_STATE "state"
#define _COMPONENT ACPI_FAN_COMPONENT
ACPI_MODULE_NAME("fan");
MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Fan Driver");
MODULE_LICENSE("GPL");
static int acpi_fan_add(struct acpi_device *device);
static int acpi_fan_remove(struct acpi_device *device, int type);
static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state);
static int acpi_fan_resume(struct acpi_device *device);
static const struct acpi_device_id fan_device_ids[] = {
{"PNP0C0B", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, fan_device_ids);
static struct acpi_driver acpi_fan_driver = {
.name = "fan",
.class = ACPI_FAN_CLASS,
.ids = fan_device_ids,
.ops = {
.add = acpi_fan_add,
.remove = acpi_fan_remove,
.suspend = acpi_fan_suspend,
.resume = acpi_fan_resume,
},
};
/* thermal cooling device callbacks */
static int fan_get_max_state(struct thermal_cooling_device *cdev, char *buf)
{
/* ACPI fan device only support two states: ON/OFF */
return sprintf(buf, "1\n");
}
static int fan_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
{
struct acpi_device *device = cdev->devdata;
int state;
int result;
if (!device)
return -EINVAL;
result = acpi_bus_get_power(device->handle, &state);
if (result)
return result;
return sprintf(buf, "%s\n", state == ACPI_STATE_D3 ? "0" :
(state == ACPI_STATE_D0 ? "1" : "unknown"));
}
static int
fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
{
struct acpi_device *device = cdev->devdata;
int result;
if (!device || (state != 0 && state != 1))
return -EINVAL;
result = acpi_bus_set_power(device->handle,
state ? ACPI_STATE_D0 : ACPI_STATE_D3);
return result;
}
static struct thermal_cooling_device_ops fan_cooling_ops = {
.get_max_state = fan_get_max_state,
.get_cur_state = fan_get_cur_state,
.set_cur_state = fan_set_cur_state,
};
/* --------------------------------------------------------------------------
FS Interface (/proc)
-------------------------------------------------------------------------- */
#ifdef CONFIG_ACPI_PROCFS
static struct proc_dir_entry *acpi_fan_dir;
static int acpi_fan_read_state(struct seq_file *seq, void *offset)
{
struct acpi_device *device = seq->private;
int state = 0;
if (device) {
if (acpi_bus_get_power(device->handle, &state))
seq_printf(seq, "status: ERROR\n");
else
seq_printf(seq, "status: %s\n",
!state ? "on" : "off");
}
return 0;
}
static int acpi_fan_state_open_fs(struct inode *inode, struct file *file)
{
return single_open(file, acpi_fan_read_state, PDE(inode)->data);
}
static ssize_t
acpi_fan_write_state(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
int result = 0;
struct seq_file *m = file->private_data;
struct acpi_device *device = m->private;
char state_string[3] = { '\0' };
if (count > sizeof(state_string) - 1)
return -EINVAL;
if (copy_from_user(state_string, buffer, count))
return -EFAULT;
state_string[count] = '\0';
if ((state_string[0] < '0') || (state_string[0] > '3'))
return -EINVAL;
if (state_string[1] == '\n')
state_string[1] = '\0';
if (state_string[1] != '\0')
return -EINVAL;
result = acpi_bus_set_power(device->handle,
simple_strtoul(state_string, NULL, 0));
if (result)
return result;
return count;
}
static const struct file_operations acpi_fan_state_ops = {
.open = acpi_fan_state_open_fs,
.read = seq_read,
.write = acpi_fan_write_state,
.llseek = seq_lseek,
.release = single_release,
.owner = THIS_MODULE,
};
static int acpi_fan_add_fs(struct acpi_device *device)
{
struct proc_dir_entry *entry = NULL;
if (!device)
return -EINVAL;
if (!acpi_device_dir(device)) {
acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
acpi_fan_dir);
if (!acpi_device_dir(device))
return -ENODEV;
}
/* 'status' [R/W] */
entry = proc_create_data(ACPI_FAN_FILE_STATE,
S_IFREG | S_IRUGO | S_IWUSR,
acpi_device_dir(device),
&acpi_fan_state_ops,
device);
if (!entry)
return -ENODEV;
return 0;
}
static int acpi_fan_remove_fs(struct acpi_device *device)
{
if (acpi_device_dir(device)) {
remove_proc_entry(ACPI_FAN_FILE_STATE, acpi_device_dir(device));
remove_proc_entry(acpi_device_bid(device), acpi_fan_dir);
acpi_device_dir(device) = NULL;
}
return 0;
}
#else
static int acpi_fan_add_fs(struct acpi_device *device)
{
return 0;
}
static int acpi_fan_remove_fs(struct acpi_device *device)
{
return 0;
}
#endif
/* --------------------------------------------------------------------------
Driver Interface
-------------------------------------------------------------------------- */
static int acpi_fan_add(struct acpi_device *device)
{
int result = 0;
int state = 0;
struct thermal_cooling_device *cdev;
if (!device)
return -EINVAL;
strcpy(acpi_device_name(device), "Fan");
strcpy(acpi_device_class(device), ACPI_FAN_CLASS);
result = acpi_bus_get_power(device->handle, &state);
if (result) {
printk(KERN_ERR PREFIX "Reading power state\n");
goto end;
}
device->flags.force_power_state = 1;
acpi_bus_set_power(device->handle, state);
device->flags.force_power_state = 0;
cdev = thermal_cooling_device_register("Fan", device,
&fan_cooling_ops);
if (IS_ERR(cdev)) {
result = PTR_ERR(cdev);
goto end;
}
dev_info(&device->dev, "registered as cooling_device%d\n", cdev->id);
device->driver_data = cdev;
result = sysfs_create_link(&device->dev.kobj,
&cdev->device.kobj,
"thermal_cooling");
if (result)
dev_err(&device->dev, "Failed to create sysfs link "
"'thermal_cooling'\n");
result = sysfs_create_link(&cdev->device.kobj,
&device->dev.kobj,
"device");
if (result)
dev_err(&device->dev, "Failed to create sysfs link "
"'device'\n");
result = acpi_fan_add_fs(device);
if (result)
goto end;
printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
acpi_device_name(device), acpi_device_bid(device),
!device->power.state ? "on" : "off");
end:
return result;
}
static int acpi_fan_remove(struct acpi_device *device, int type)
{
struct thermal_cooling_device *cdev = acpi_driver_data(device);
if (!device || !cdev)
return -EINVAL;
acpi_fan_remove_fs(device);
sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
sysfs_remove_link(&cdev->device.kobj, "device");
thermal_cooling_device_unregister(cdev);
return 0;
}
static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state)
{
if (!device)
return -EINVAL;
acpi_bus_set_power(device->handle, ACPI_STATE_D0);
return AE_OK;
}
static int acpi_fan_resume(struct acpi_device *device)
{
int result = 0;
int power_state = 0;
if (!device)
return -EINVAL;
result = acpi_bus_get_power(device->handle, &power_state);
if (result) {
printk(KERN_ERR PREFIX
"Error reading fan power state\n");
return result;
}
device->flags.force_power_state = 1;
acpi_bus_set_power(device->handle, power_state);
device->flags.force_power_state = 0;
return result;
}
static int __init acpi_fan_init(void)
{
int result = 0;
#ifdef CONFIG_ACPI_PROCFS
acpi_fan_dir = proc_mkdir(ACPI_FAN_CLASS, acpi_root_dir);
if (!acpi_fan_dir)
return -ENODEV;
#endif
result = acpi_bus_register_driver(&acpi_fan_driver);
if (result < 0) {
remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
return -ENODEV;
}
return 0;
}
static void __exit acpi_fan_exit(void)
{
acpi_bus_unregister_driver(&acpi_fan_driver);
remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
return;
}
module_init(acpi_fan_init);
module_exit(acpi_fan_exit);