Commit 0fbf87ca authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: add semaphore and user count to input_dev structure; 


       serialize open and close calls and ensure that device's
       open and close methods are only called when first user
       opens it or last user closes it.

Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 58a00776

drivers/input/input.c

+28 −5
Original line number Diff line number Diff line
@@ -219,10 +219,24 @@ void input_release_device(struct input_handle *handle) 


int input_open_device(struct input_handle *handle)

{

	struct input_dev *dev = handle->dev;

	int err;



	err = down_interruptible(&dev->sem);

	if (err)

		return err;



	handle->open++;

	if (handle->dev->open)

		return handle->dev->open(handle->dev);

	return 0;



	if (!dev->users++ && dev->open)

		err = dev->open(dev);



	if (err)

		handle->open--;



	up(&dev->sem);



	return err;

}



int input_flush_device(struct input_handle* handle, struct file* file)
@@ -235,10 +249,17 @@ int input_flush_device(struct input_handle* handle, struct file* file) 


void input_close_device(struct input_handle *handle)

{

	struct input_dev *dev = handle->dev;



	input_release_device(handle);

	if (handle->dev->close)

		handle->dev->close(handle->dev);



	down(&dev->sem);



	if (!--dev->users && dev->close)

		dev->close(dev);

	handle->open--;



	up(&dev->sem);

}



static void input_link_handle(struct input_handle *handle)
@@ -415,6 +436,8 @@ void input_register_device(struct input_dev *dev) 


	set_bit(EV_SYN, dev->evbit);



	init_MUTEX(&dev->sem);



	/*

	 * If delay and period are pre-set by the driver, then autorepeating

	 * is handled by the driver itself and we don't do it in input.c.

include/linux/input.h

+4 −0
Original line number Diff line number Diff line
@@ -859,6 +859,10 @@ struct input_dev { 
	int (*erase_effect)(struct input_dev *dev, int effect_id);



	struct input_handle *grab;



	struct semaphore sem;	/* serializes open and close operations */

	unsigned int users;



	struct device *dev;



	struct list_head	h_list;