HID: hid-input: allow input_configured callback return errors

When configuring input device via input_configured callback we may
encounter errors (for example input_mt_init_slots() may fail). Instead
of continuing with half-initialized input device let's allow driver
indicate failures.

Signed-off-by: Jaikumar Ganesh <jaikumarg@android.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Nikolai Kondrashov <Nikolai.Kondrashov@redhat.com>
Acked-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 426b2f1..2ed42d8 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -725,12 +725,13 @@
 		mt_sync_frame(td, report->field[0]->hidinput->input);
 }
 
-static void mt_touch_input_configured(struct hid_device *hdev,
+static int mt_touch_input_configured(struct hid_device *hdev,
 					struct hid_input *hi)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
 	struct mt_class *cls = &td->mtclass;
 	struct input_dev *input = hi->input;
+	int ret;
 
 	if (!td->maxcontacts)
 		td->maxcontacts = MT_DEFAULT_MAXCONTACT;
@@ -752,9 +753,12 @@
 	if (td->is_buttonpad)
 		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
 
-	input_mt_init_slots(input, td->maxcontacts, td->mt_flags);
+	ret = input_mt_init_slots(input, td->maxcontacts, td->mt_flags);
+	if (ret)
+		return ret;
 
 	td->mt_flags = 0;
+	return 0;
 }
 
 static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
@@ -930,15 +934,19 @@
 		cls->quirks &= ~MT_QUIRK_CONTACT_CNT_ACCURATE;
 }
 
-static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
+static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
 	char *name;
 	const char *suffix = NULL;
 	struct hid_field *field = hi->report->field[0];
+	int ret;
 
-	if (hi->report->id == td->mt_report_id)
-		mt_touch_input_configured(hdev, hi);
+	if (hi->report->id == td->mt_report_id) {
+		ret = mt_touch_input_configured(hdev, hi);
+		if (ret)
+			return ret;
+	}
 
 	/*
 	 * some egalax touchscreens have "application == HID_DG_TOUCHSCREEN"
@@ -989,6 +997,8 @@
 			hi->input->name = name;
 		}
 	}
+
+	return 0;
 }
 
 static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)