---

yaml
---
r: 183111
b: refs/heads/master
c: ef7995f
h: refs/heads/master
i:
  183109: 8521909
  183107: d7a647d
  183103: 23a2060
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 45cdba4d376adfd30cfbda1b7d43110818d967cc
+refs/heads/master: ef7995f4e46b1677f3eaaf547316e1a910b38dcb

trunk/drivers/input/input.c

@@ -86,24 +86,40 @@ static int input_defuzz_abs_event(int value, int old_val, int fuzz)
 }
 
 /*
- * Pass event through all open handles. This function is called with
+ * Pass event first through all filters and then, if event has not been
+ * filtered out, through all open handles. This function is called with
  * dev->event_lock held and interrupts disabled.
  */
 static void input_pass_event(struct input_dev *dev,
 			     unsigned int type, unsigned int code, int value)
 {
+	struct input_handler *handler;
 	struct input_handle *handle;
 
 	rcu_read_lock();
 
 	handle = rcu_dereference(dev->grab);
 	if (handle)
 		handle->handler->event(handle, type, code, value);
-	else
-		list_for_each_entry_rcu(handle, &dev->h_list, d_node)
-			if (handle->open)
-				handle->handler->event(handle,
-							type, code, value);
+	else {
+		bool filtered = false;
+
+		list_for_each_entry_rcu(handle, &dev->h_list, d_node) {
+			if (!handle->open)
+				continue;
+
+			handler = handle->handler;
+			if (!handler->filter) {
+				if (filtered)
+					break;
+
+				handler->event(handle, type, code, value);
+
+			} else if (handler->filter(handle, type, code, value))
+				filtered = true;
+		}
+	}
+
 	rcu_read_unlock();
 }
 
@@ -990,6 +1006,8 @@ static int input_handlers_seq_show(struct seq_file *seq, void *v)
 	union input_seq_state *state = (union input_seq_state *)&seq->private;
 
 	seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
+	if (handler->filter)
+		seq_puts(seq, " (filter)");
 	if (handler->fops)
 		seq_printf(seq, " Minor=%d", handler->minor);
 	seq_putc(seq, '\n');
@@ -1803,7 +1821,16 @@ int input_register_handle(struct input_handle *handle)
 	error = mutex_lock_interruptible(&dev->mutex);
 	if (error)
 		return error;
-	list_add_tail_rcu(&handle->d_node, &dev->h_list);
+
+	/*
+	 * Filters go to the head of the list, normal handlers
+	 * to the tail.
+	 */
+	if (handler->filter)
+		list_add_rcu(&handle->d_node, &dev->h_list);
+	else
+		list_add_tail_rcu(&handle->d_node, &dev->h_list);
+
 	mutex_unlock(&dev->mutex);
 
 	/*

trunk/include/linux/input.h

@@ -1198,6 +1198,8 @@ struct input_handle;
  * @event: event handler. This method is being called by input core with
  *	interrupts disabled and dev->event_lock spinlock held and so
  *	it may not sleep
+ * @filter: similar to @event; separates normal event handlers from
+ *	"filters".
  * @connect: called when attaching a handler to an input device
  * @disconnect: disconnects a handler from input device
  * @start: starts handler for given handle. This function is called by
@@ -1219,6 +1221,11 @@ struct input_handle;
  * same time. All of them will get their copy of input event generated by
  * the device.
  *
+ * The very same structure is used to implement input filters. Input core
+ * allows filters to run first and will not pass event to regular handlers
+ * if any of the filters indicate that the event should be filtered (by
+ * returning %true from their filter() method).
+ *
  * Note that input core serializes calls to connect() and disconnect()
  * methods.
  */
@@ -1227,6 +1234,7 @@ struct input_handler {
 	void *private;
 
 	void (*event)(struct input_handle *handle, unsigned int type, unsigned int code, int value);
+	bool (*filter)(struct input_handle *handle, unsigned int type, unsigned int code, int value);
 	int (*connect)(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id);
 	void (*disconnect)(struct input_handle *handle);
 	void (*start)(struct input_handle *handle);