1 files changed, 27 insertions, 11 deletions

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index d398f1321f14..c30204f2fa30 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -237,6 +237,31 @@ void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
 EXPORT_SYMBOL(input_mt_report_pointer_emulation);
 
 /**
+ * input_mt_drop_unused() - Inactivate slots not seen in this frame
+ * @dev: input device with allocated MT slots
+ *
+ * Lift all slots not seen since the last call to this function.
+ */
+void input_mt_drop_unused(struct input_dev *dev)
+{
+        struct input_mt *mt = dev->mt;
+        int i;
+
+        if (!mt)
+                return;
+
+        for (i = 0; i < mt->num_slots; i++) {
+                if (!input_mt_is_used(mt, &mt->slots[i])) {
+                        input_mt_slot(dev, i);
+                        input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
+                }
+        }
+
+        mt->frame++;
+}
+EXPORT_SYMBOL(input_mt_drop_unused);
+
+/**
  * input_mt_sync_frame() - synchronize mt frame
  * @dev: input device with allocated MT slots
  *
@@ -247,27 +272,18 @@ EXPORT_SYMBOL(input_mt_report_pointer_emulation);
 void input_mt_sync_frame(struct input_dev *dev)
 {
         struct input_mt *mt = dev->mt;
-        struct input_mt_slot *s;
         bool use_count = false;
 
         if (!mt)
                 return;
 
-        if (mt->flags & INPUT_MT_DROP_UNUSED) {
-                for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
-                        if (input_mt_is_used(mt, s))
-                                continue;
-                        input_mt_slot(dev, s - mt->slots);
-                        input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
-                }
-        }
+        if (mt->flags & INPUT_MT_DROP_UNUSED)
+                input_mt_drop_unused(dev);
 
         if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
                 use_count = true;
 
         input_mt_report_pointer_emulation(dev, use_count);
-
-        mt->frame++;
 }
 EXPORT_SYMBOL(input_mt_sync_frame);