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Commit 2e2e3b96 authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: sparse-keymap - implement safer freeing of the keymap 



Allow calling sparse_keymap_free() before unregistering input device
whithout risk of racing with EVIOCGETKEYCODE and EVIOCSETKEYCODE.
This makes life of drivers writers easier.

Acked-by: default avatarYong Wang <yong.y.wang@intel.com>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 13bad37b

drivers/input/input.c

+8 −1
Original line number Diff line number Diff line
@@ -659,7 +659,14 @@ static int input_default_setkeycode(struct input_dev *dev, 
int input_get_keycode(struct input_dev *dev,

		      unsigned int scancode, unsigned int *keycode)

{

	return dev->getkeycode(dev, scancode, keycode);

	unsigned long flags;

	int retval;



	spin_lock_irqsave(&dev->event_lock, flags);

	retval = dev->getkeycode(dev, scancode, keycode);

	spin_unlock_irqrestore(&dev->event_lock, flags);



	return retval;

}

EXPORT_SYMBOL(input_get_keycode);

drivers/input/sparse-keymap.c

+32 −18
Original line number Diff line number Diff line
@@ -67,13 +67,15 @@ static int sparse_keymap_getkeycode(struct input_dev *dev, 
				    unsigned int scancode,

				    unsigned int *keycode)

{

	const struct key_entry *key =

			sparse_keymap_entry_from_scancode(dev, scancode);

	const struct key_entry *key;



	if (dev->keycode) {

		key = sparse_keymap_entry_from_scancode(dev, scancode);

		if (key && key->type == KE_KEY) {

			*keycode = key->keycode;

			return 0;

		}

	}



	return -EINVAL;

}
@@ -85,9 +87,7 @@ static int sparse_keymap_setkeycode(struct input_dev *dev, 
	struct key_entry *key;

	int old_keycode;



	if (keycode < 0 || keycode > KEY_MAX)

		return -EINVAL;



	if (dev->keycode) {

		key = sparse_keymap_entry_from_scancode(dev, scancode);

		if (key && key->type == KE_KEY) {

			old_keycode = key->keycode;
@@ -97,6 +97,7 @@ static int sparse_keymap_setkeycode(struct input_dev *dev, 
				clear_bit(old_keycode, dev->keybit);

			return 0;

		}

	}



	return -EINVAL;

}
@@ -175,14 +176,27 @@ EXPORT_SYMBOL(sparse_keymap_setup); 
 *

 * This function is used to free memory allocated by sparse keymap

 * in an input device that was set up by sparse_keymap_setup().

 * NOTE: It is safe to cal this function while input device is

 * still registered (however the drivers should care not to try to

 * use freed keymap and thus have to shut off interrups/polling

 * before freeing the keymap).

 */

void sparse_keymap_free(struct input_dev *dev)

{

	unsigned long flags;



	/*

	 * Take event lock to prevent racing with input_get_keycode()

	 * and input_set_keycode() if we are called while input device

	 * is still registered.

	 */

	spin_lock_irqsave(&dev->event_lock, flags);



	kfree(dev->keycode);

	dev->keycode = NULL;

	dev->keycodemax = 0;

	dev->getkeycode = NULL;

	dev->setkeycode = NULL;



	spin_unlock_irqrestore(&dev->event_lock, flags);

}

EXPORT_SYMBOL(sparse_keymap_free);