Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index a746017..1f9bc44 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -1,25 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Copyright (c) 2001 Paul Stewart
  *  Copyright (c) 2001 Vojtech Pavlik
  *
  *  HID char devices, giving access to raw HID device events.
- *
  */
 
 /*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  *
  * Should you need to contact me, the author, you can do so either by
  * e-mail - mail your message to Paul Stewart <stewart@wetlogic.net>
@@ -297,6 +284,14 @@
 	spin_unlock_irq(&list->hiddev->list_lock);
 
 	mutex_lock(&hiddev->existancelock);
+	/*
+	 * recheck exist with existance lock held to
+	 * avoid opening a disconnected device
+	 */
+	if (!list->hiddev->exist) {
+		res = -ENODEV;
+		goto bail_unlock;
+	}
 	if (!list->hiddev->open++)
 		if (list->hiddev->exist) {
 			struct hid_device *hid = hiddev->hid;
@@ -313,6 +308,10 @@
 	hid_hw_power(hid, PM_HINT_NORMAL);
 bail_unlock:
 	mutex_unlock(&hiddev->existancelock);
+
+	spin_lock_irq(&list->hiddev->list_lock);
+	list_del(&list->node);
+	spin_unlock_irq(&list->hiddev->list_lock);
 bail:
 	file->private_data = NULL;
 	vfree(list);
@@ -429,7 +428,7 @@
 
 	poll_wait(file, &list->hiddev->wait, wait);
 	if (list->head != list->tail)
-		return EPOLLIN | EPOLLRDNORM;
+		return EPOLLIN | EPOLLRDNORM | EPOLLOUT;
 	if (!list->hiddev->exist)
 		return EPOLLERR | EPOLLHUP;
 	return 0;