From 2e2e3b96d98d5c17e9c09bc6088df3e182a71814 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Sun, 21 Mar 2010 22:56:15 -0700 Subject: 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: Yong Wang Signed-off-by: Dmitry Torokhov --- drivers/input/sparse-keymap.c | 50 +++++++++++++++++++++++++++---------------- 1 file changed, 32 insertions(+), 18 deletions(-) (limited to 'drivers/input/sparse-keymap.c') diff --git a/drivers/input/sparse-keymap.c b/drivers/input/sparse-keymap.c index f64e004935a9..2434ac5d43fe 100644 --- a/drivers/input/sparse-keymap.c +++ b/drivers/input/sparse-keymap.c @@ -67,12 +67,14 @@ 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 (key && key->type == KE_KEY) { - *keycode = key->keycode; - return 0; + if (dev->keycode) { + key = sparse_keymap_entry_from_scancode(dev, scancode); + if (key && key->type == KE_KEY) { + *keycode = key->keycode; + return 0; + } } return -EINVAL; @@ -85,17 +87,16 @@ static int sparse_keymap_setkeycode(struct input_dev *dev, struct key_entry *key; int old_keycode; - if (keycode < 0 || keycode > KEY_MAX) - return -EINVAL; - - key = sparse_keymap_entry_from_scancode(dev, scancode); - if (key && key->type == KE_KEY) { - old_keycode = key->keycode; - key->keycode = keycode; - set_bit(keycode, dev->keybit); - if (!sparse_keymap_entry_from_keycode(dev, old_keycode)) - clear_bit(old_keycode, dev->keybit); - return 0; + if (dev->keycode) { + key = sparse_keymap_entry_from_scancode(dev, scancode); + if (key && key->type == KE_KEY) { + old_keycode = key->keycode; + key->keycode = keycode; + set_bit(keycode, dev->keybit); + if (!sparse_keymap_entry_from_keycode(dev, old_keycode)) + 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); -- cgit v1.2.3-59-g8ed1b