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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2010-03-21 22:56:15 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2010-03-21 23:00:51 -0700
commit2e2e3b96d98d5c17e9c09bc6088df3e182a71814 (patch)
tree0ed49ca3ee60a9deb465d8aa4894365bd8d3030d /drivers/input/sparse-keymap.c
parentInput: update the status of the Multitouch X driver project (diff)
downloadlinux-dev-2e2e3b96d98d5c17e9c09bc6088df3e182a71814.tar.xz
linux-dev-2e2e3b96d98d5c17e9c09bc6088df3e182a71814.zip
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 <yong.y.wang@intel.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/sparse-keymap.c')
-rw-r--r--drivers/input/sparse-keymap.c50
1 files changed, 32 insertions, 18 deletions
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);