Input: cleanse capabilities bits before registering device

[deliverable/linux.git] / drivers / input / input.c

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 2266ecbfbc010789390c9a5ebb36b72d0960526e..a31394c1eca818aa2b665c95203a9df5e0b60a69 100644 (file)
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -296,9 +296,15 @@ static void input_handle_event(struct input_dev *dev,
  * @value: value of the event
  *
  * This function should be used by drivers implementing various input
- * devices. See also input_inject_event().
+ * devices to report input events. See also input_inject_event().
+ *
+ * NOTE: input_event() may be safely used right after input device was
+ * allocated with input_allocate_device(), even before it is registered
+ * with input_register_device(), but the event will not reach any of the
+ * input handlers. Such early invocation of input_event() may be used
+ * to 'seed' initial state of a switch or initial position of absolute
+ * axis, etc.
  */
-
 void input_event(struct input_dev *dev,
                 unsigned int type, unsigned int code, int value)
 {
@@ -607,12 +613,12 @@ static int input_default_setkeycode(struct input_dev *dev,
                }
        }
 
-       clear_bit(old_keycode, dev->keybit);
-       set_bit(keycode, dev->keybit);
+       __clear_bit(old_keycode, dev->keybit);
+       __set_bit(keycode, dev->keybit);
 
        for (i = 0; i < dev->keycodemax; i++) {
                if (input_fetch_keycode(dev, i) == old_keycode) {
-                       set_bit(old_keycode, dev->keybit);
+                       __set_bit(old_keycode, dev->keybit);
                        break; /* Setting the bit twice is useless, so break */
                }
        }
@@ -670,6 +676,9 @@ int input_set_keycode(struct input_dev *dev, int scancode, int keycode)
        if (retval)
                goto out;
 
+       /* Make sure KEY_RESERVED did not get enabled. */
+       __clear_bit(KEY_RESERVED, dev->keybit);
+
        /*
         * Simulate keyup event if keycode is not present
         * in the keymap anymore
@@ -1488,6 +1497,25 @@ void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int
 }
 EXPORT_SYMBOL(input_set_capability);
 
+#define INPUT_CLEANSE_BITMASK(dev, type, bits)                         \
+       do {                                                            \
+               if (!test_bit(EV_##type, dev->evbit))                   \
+                       memset(dev->bits##bit, 0,                       \
+                               sizeof(dev->bits##bit));                \
+       } while (0)
+
+static void input_cleanse_bitmasks(struct input_dev *dev)
+{
+       INPUT_CLEANSE_BITMASK(dev, KEY, key);
+       INPUT_CLEANSE_BITMASK(dev, REL, rel);
+       INPUT_CLEANSE_BITMASK(dev, ABS, abs);
+       INPUT_CLEANSE_BITMASK(dev, MSC, msc);
+       INPUT_CLEANSE_BITMASK(dev, LED, led);
+       INPUT_CLEANSE_BITMASK(dev, SND, snd);
+       INPUT_CLEANSE_BITMASK(dev, FF, ff);
+       INPUT_CLEANSE_BITMASK(dev, SW, sw);
+}
+
 /**
  * input_register_device - register device with input core
  * @dev: device to be registered
@@ -1507,13 +1535,19 @@ int input_register_device(struct input_dev *dev)
        const char *path;
        int error;
 
+       /* Every input device generates EV_SYN/SYN_REPORT events. */
        __set_bit(EV_SYN, dev->evbit);
 
+       /* KEY_RESERVED is not supposed to be transmitted to userspace. */
+       __clear_bit(KEY_RESERVED, dev->keybit);
+
+       /* Make sure that bitmasks not mentioned in dev->evbit are clean. */
+       input_cleanse_bitmasks(dev);
+
        /*
         * 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.
         */
-
        init_timer(&dev->timer);
        if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
                dev->timer.data = (long) dev;
@@ -1657,6 +1691,38 @@ void input_unregister_handler(struct input_handler *handler)
 }
 EXPORT_SYMBOL(input_unregister_handler);
 
+/**
+ * input_handler_for_each_handle - handle iterator
+ * @handler: input handler to iterate
+ * @data: data for the callback
+ * @fn: function to be called for each handle
+ *
+ * Iterate over @bus's list of devices, and call @fn for each, passing
+ * it @data and stop when @fn returns a non-zero value. The function is
+ * using RCU to traverse the list and therefore may be usind in atonic
+ * contexts. The @fn callback is invoked from RCU critical section and
+ * thus must not sleep.
+ */
+int input_handler_for_each_handle(struct input_handler *handler, void *data,
+                                 int (*fn)(struct input_handle *, void *))
+{
+       struct input_handle *handle;
+       int retval = 0;
+
+       rcu_read_lock();
+
+       list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
+               retval = fn(handle, data);
+               if (retval)
+                       break;
+       }
+
+       rcu_read_unlock();
+
+       return retval;
+}
+EXPORT_SYMBOL(input_handler_for_each_handle);
+
 /**
  * input_register_handle - register a new input handle
  * @handle: handle to register
@@ -1690,7 +1756,7 @@ int input_register_handle(struct input_handle *handle)
         * we can't be racing with input_unregister_handle()
         * and so separate lock is not needed here.
         */
-       list_add_tail(&handle->h_node, &handler->h_list);
+       list_add_tail_rcu(&handle->h_node, &handler->h_list);
 
        if (handler->start)
                handler->start(handle);
@@ -1713,7 +1779,7 @@ void input_unregister_handle(struct input_handle *handle)
 {
        struct input_dev *dev = handle->dev;
 
-       list_del_init(&handle->h_node);
+       list_del_rcu(&handle->h_node);
 
        /*
         * Take dev->mutex to prevent race with input_release_device().
@@ -1721,6 +1787,7 @@ void input_unregister_handle(struct input_handle *handle)
        mutex_lock(&dev->mutex);
        list_del_rcu(&handle->d_node);
        mutex_unlock(&dev->mutex);
+
        synchronize_rcu();
 }
 EXPORT_SYMBOL(input_unregister_handle);