kernel_optimize_test/drivers/input/input-polldev.c
Dmitry Torokhov d1fefd5b73 Input: remove race when instantiating polled device attributes
Polled device's attributes controlling polling rate and whether polling is
enabled are attached to input device. We should have device core
instantiate them for us, so that they are created by the time new device
notification is sent to userspace, instead of doing it ourselves
afterwards.

Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2014-05-14 16:40:03 -07:00

253 lines
6.1 KiB
C

/*
* Generic implementation of a polled input device
* Copyright (c) 2007 Dmitry Torokhov
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/jiffies.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/module.h>
#include <linux/input-polldev.h>
MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION("Generic implementation of a polled input device");
MODULE_LICENSE("GPL v2");
MODULE_VERSION("0.1");
static void input_polldev_queue_work(struct input_polled_dev *dev)
{
unsigned long delay;
delay = msecs_to_jiffies(dev->poll_interval);
if (delay >= HZ)
delay = round_jiffies_relative(delay);
queue_delayed_work(system_freezable_wq, &dev->work, delay);
}
static void input_polled_device_work(struct work_struct *work)
{
struct input_polled_dev *dev =
container_of(work, struct input_polled_dev, work.work);
dev->poll(dev);
input_polldev_queue_work(dev);
}
static int input_open_polled_device(struct input_dev *input)
{
struct input_polled_dev *dev = input_get_drvdata(input);
if (dev->open)
dev->open(dev);
/* Only start polling if polling is enabled */
if (dev->poll_interval > 0) {
dev->poll(dev);
input_polldev_queue_work(dev);
}
return 0;
}
static void input_close_polled_device(struct input_dev *input)
{
struct input_polled_dev *dev = input_get_drvdata(input);
cancel_delayed_work_sync(&dev->work);
if (dev->close)
dev->close(dev);
}
/* SYSFS interface */
static ssize_t input_polldev_get_poll(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct input_polled_dev *polldev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", polldev->poll_interval);
}
static ssize_t input_polldev_set_poll(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t count)
{
struct input_polled_dev *polldev = dev_get_drvdata(dev);
struct input_dev *input = polldev->input;
unsigned int interval;
int err;
err = kstrtouint(buf, 0, &interval);
if (err)
return err;
if (interval < polldev->poll_interval_min)
return -EINVAL;
if (interval > polldev->poll_interval_max)
return -EINVAL;
mutex_lock(&input->mutex);
polldev->poll_interval = interval;
if (input->users) {
cancel_delayed_work_sync(&polldev->work);
if (polldev->poll_interval > 0)
input_polldev_queue_work(polldev);
}
mutex_unlock(&input->mutex);
return count;
}
static DEVICE_ATTR(poll, S_IRUGO | S_IWUSR, input_polldev_get_poll,
input_polldev_set_poll);
static ssize_t input_polldev_get_max(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct input_polled_dev *polldev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", polldev->poll_interval_max);
}
static DEVICE_ATTR(max, S_IRUGO, input_polldev_get_max, NULL);
static ssize_t input_polldev_get_min(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct input_polled_dev *polldev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", polldev->poll_interval_min);
}
static DEVICE_ATTR(min, S_IRUGO, input_polldev_get_min, NULL);
static struct attribute *sysfs_attrs[] = {
&dev_attr_poll.attr,
&dev_attr_max.attr,
&dev_attr_min.attr,
NULL
};
static struct attribute_group input_polldev_attribute_group = {
.attrs = sysfs_attrs
};
static const struct attribute_group *input_polldev_attribute_groups[] = {
&input_polldev_attribute_group,
NULL
};
/**
* input_allocate_polled_device - allocate memory for polled device
*
* The function allocates memory for a polled device and also
* for an input device associated with this polled device.
*/
struct input_polled_dev *input_allocate_polled_device(void)
{
struct input_polled_dev *dev;
dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
if (!dev)
return NULL;
dev->input = input_allocate_device();
if (!dev->input) {
kfree(dev);
return NULL;
}
return dev;
}
EXPORT_SYMBOL(input_allocate_polled_device);
/**
* input_free_polled_device - free memory allocated for polled device
* @dev: device to free
*
* The function frees memory allocated for polling device and drops
* reference to the associated input device.
*/
void input_free_polled_device(struct input_polled_dev *dev)
{
if (dev) {
input_free_device(dev->input);
kfree(dev);
}
}
EXPORT_SYMBOL(input_free_polled_device);
/**
* input_register_polled_device - register polled device
* @dev: device to register
*
* The function registers previously initialized polled input device
* with input layer. The device should be allocated with call to
* input_allocate_polled_device(). Callers should also set up poll()
* method and set up capabilities (id, name, phys, bits) of the
* corresponding input_dev structure.
*/
int input_register_polled_device(struct input_polled_dev *dev)
{
struct input_dev *input = dev->input;
int error;
input_set_drvdata(input, dev);
INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
if (!dev->poll_interval)
dev->poll_interval = 500;
if (!dev->poll_interval_max)
dev->poll_interval_max = dev->poll_interval;
input->open = input_open_polled_device;
input->close = input_close_polled_device;
input->dev.groups = input_polldev_attribute_groups;
error = input_register_device(input);
if (error)
return error;
/*
* Take extra reference to the underlying input device so
* that it survives call to input_unregister_polled_device()
* and is deleted only after input_free_polled_device()
* has been invoked. This is needed to ease task of freeing
* sparse keymaps.
*/
input_get_device(input);
return 0;
}
EXPORT_SYMBOL(input_register_polled_device);
/**
* input_unregister_polled_device - unregister polled device
* @dev: device to unregister
*
* The function unregisters previously registered polled input
* device from input layer. Polling is stopped and device is
* ready to be freed with call to input_free_polled_device().
*/
void input_unregister_polled_device(struct input_polled_dev *dev)
{
input_unregister_device(dev->input);
}
EXPORT_SYMBOL(input_unregister_polled_device);