HID: wacom: Properly free inputs if 'wacom_allocate_inputs' fails

The 'wacom_allocate_inputs' function tries to allocate three input devices: one
each for the pen, touch, and pad. The pointers that are returned by the
'wacom_allocate_input' calls are temporarily stored to local variables where
they are checked to ensure they're non-null before storing them in the
'wacom_wac' structure. If an allocation fails,  the 'wacom_free_inputs'
function is called to reclaim the memory. Unfortunately, 'wacom_free_inputs' is
called prior to the pointers being copied, so it is not actually able to free
anything.

This patch has the calls to 'wacom_allocate_input' store the pointer directly
in the 'wacom_wac' structure where they can be freed. Also, it replaces the
call to 'wacom_free_inputs' with the (more general) 'wacom_clean_inputs' and
removes the no-longer-used function.

[jkosina@suse.com: modify to resolve conflict with 67e123ff ("Delete
 unnecessary checks")]
Signed-off-by: NJason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: NJiri Kosina <jkosina@suse.com>

drivers/hid/wacom_sys.c

@@ -1145,40 +1145,6 @@ static struct input_dev *wacom_allocate_input(struct wacom *wacom)
 	return input_dev;
 }
 
-static void wacom_free_inputs(struct wacom *wacom)
-{
-	struct wacom_wac *wacom_wac = &(wacom->wacom_wac);
-
-	input_free_device(wacom_wac->pen_input);
-	input_free_device(wacom_wac->touch_input);
-	input_free_device(wacom_wac->pad_input);
-	wacom_wac->pen_input = NULL;
-	wacom_wac->touch_input = NULL;
-	wacom_wac->pad_input = NULL;
-}
-
-static int wacom_allocate_inputs(struct wacom *wacom)
-{
-	struct input_dev *pen_input_dev, *touch_input_dev, *pad_input_dev;
-	struct wacom_wac *wacom_wac = &(wacom->wacom_wac);
-
-	pen_input_dev = wacom_allocate_input(wacom);
-	touch_input_dev = wacom_allocate_input(wacom);
-	pad_input_dev = wacom_allocate_input(wacom);
-	if (!pen_input_dev || !touch_input_dev || !pad_input_dev) {
-		wacom_free_inputs(wacom);
-		return -ENOMEM;
-	}
-
-	wacom_wac->pen_input = pen_input_dev;
-	wacom_wac->touch_input = touch_input_dev;
-	wacom_wac->touch_input->name = wacom_wac->touch_name;
-	wacom_wac->pad_input = pad_input_dev;
-	wacom_wac->pad_input->name = wacom_wac->pad_name;
-
-	return 0;
-}
-
 static void wacom_clean_inputs(struct wacom *wacom)
 {
 	if (wacom->wacom_wac.pen_input) {
@@ -1205,6 +1171,24 @@ static void wacom_clean_inputs(struct wacom *wacom)
 	wacom_destroy_leds(wacom);
 }
 
+static int wacom_allocate_inputs(struct wacom *wacom)
+{
+	struct wacom_wac *wacom_wac = &(wacom->wacom_wac);
+
+	wacom_wac->pen_input = wacom_allocate_input(wacom);
+	wacom_wac->touch_input = wacom_allocate_input(wacom);
+	wacom_wac->pad_input = wacom_allocate_input(wacom);
+	if (!wacom_wac->pen_input || !wacom_wac->touch_input || !wacom_wac->pad_input) {
+		wacom_clean_inputs(wacom);
+		return -ENOMEM;
+	}
+
+	wacom_wac->touch_input->name = wacom_wac->touch_name;
+	wacom_wac->pad_input->name = wacom_wac->pad_name;
+
+	return 0;
+}
+
 static int wacom_register_inputs(struct wacom *wacom)
 {
 	struct input_dev *pen_input_dev, *touch_input_dev, *pad_input_dev;