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-rw-r--r--drivers/input/input.c41
-rw-r--r--include/linux/input.h8
2 files changed, 42 insertions, 7 deletions
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 6c161e220868..7080a9d4b840 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -86,12 +86,14 @@ 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();
@@ -99,11 +101,25 @@ static void input_pass_event(struct input_dev *dev,
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);
/*
diff --git a/include/linux/input.h b/include/linux/input.h
index 7be8a6537b57..6c9d3d49fa91 100644
--- a/include/linux/input.h
+++ b/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);