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hwmon: (ams) Fix locking issues

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Use a separate mutex to serialize input device creation/removal,
otheriwse we deadlock if we try to remove input device while it is
being polled. Also do not take ams_info.lock when it is not needed.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Dmitry Torokhov
2008-10-17 17:51:12 +02:00
committed by Jean Delvare
parent 0a02002268
commit ee4cd32ee8
4 changed files with 56 additions and 65 deletions
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59
drivers/hwmon/ams/ams-input.c
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@ -27,6 +27,8 @@ static unsigned int invert;
module_param(invert, bool, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(invert, "Invert input data on X and Y axis");
static DEFINE_MUTEX(ams_input_mutex);
static void ams_idev_poll(struct input_polled_dev *dev)
{
struct input_dev *idev = dev->input;
@ -50,13 +52,11 @@ static void ams_idev_poll(struct input_polled_dev *dev)
}
/* Call with ams_info.lock held! */
static void ams_input_enable(void)
static int ams_input_enable(void)
{
struct input_dev *input;
s8 x, y, z;
if (ams_info.idev)
return;
int error;
ams_sensors(&x, &y, &z);
ams_info.xcalib = x;
@ -65,7 +65,7 @@ static void ams_input_enable(void)
ams_info.idev = input_allocate_polled_device();
if (!ams_info.idev)
return;
return -ENOMEM;
ams_info.idev->poll = ams_idev_poll;
ams_info.idev->poll_interval = 25;
@ -84,14 +84,18 @@ static void ams_input_enable(void)
set_bit(EV_KEY, input->evbit);
set_bit(BTN_TOUCH, input->keybit);
if (input_register_polled_device(ams_info.idev)) {
error = input_register_polled_device(ams_info.idev);
if (error) {
input_free_polled_device(ams_info.idev);
ams_info.idev = NULL;
return;
return error;
}
joystick = 1;
return 0;
}
/* Call with ams_info.lock held! */
static void ams_input_disable(void)
{
if (ams_info.idev) {
@ -99,6 +103,8 @@ static void ams_input_disable(void)
input_free_polled_device(ams_info.idev);
ams_info.idev = NULL;
}
joystick = 0;
}
static ssize_t ams_input_show_joystick(struct device *dev,
@ -110,39 +116,42 @@ static ssize_t ams_input_show_joystick(struct device *dev,
static ssize_t ams_input_store_joystick(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
if (sscanf(buf, "%d\n", &joystick) != 1)
unsigned long enable;
int error = 0;
if (strict_strtoul(buf, 0, &enable) || enable > 1)
return -EINVAL;
mutex_lock(&ams_info.lock);
mutex_lock(&ams_input_mutex);
if (joystick)
ams_input_enable();
else
ams_input_disable();
if (enable != joystick) {
if (enable)
error = ams_input_enable();
else
ams_input_disable();
}
mutex_unlock(&ams_info.lock);
mutex_unlock(&ams_input_mutex);
return count;
return error ? error : count;
}
static DEVICE_ATTR(joystick, S_IRUGO | S_IWUSR,
ams_input_show_joystick, ams_input_store_joystick);
/* Call with ams_info.lock held! */
int ams_input_init(void)
{
int result;
result = device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
if (!result && joystick)
if (joystick)
ams_input_enable();
return result;
return device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
}
/* Call with ams_info.lock held! */
void ams_input_exit(void)
{
ams_input_disable();
device_remove_file(&ams_info.of_dev->dev, &dev_attr_joystick);
mutex_lock(&ams_input_mutex);
ams_input_disable();
mutex_unlock(&ams_input_mutex);
}