From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60813C432C0 for ; Wed, 27 Nov 2019 20:48:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D35F21826 for ; Wed, 27 Nov 2019 20:48:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887715; bh=EAxCQth2ZKk/kGjhKRAbSAUj7vT5Dv3HrY5a2a8j1CI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MgXYPwptZTX7vHIp+TQtC5moLrjoWogP0PR1Xi7DfxeZ1qcUhPD+sEkXi1KoWyjCs ytQJ3QlDcRMwLYbjB4RTCUfsKrm0Q6gZcm9u6HV/0WKKrd6tznDrzsmM6XYwu3OhdV 21RVov2fNLn919sAFMEOdm26aY3HT8sMTywxZxhA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730161AbfK0Use (ORCPT ); Wed, 27 Nov 2019 15:48:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:33792 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727893AbfK0Usa (ORCPT ); Wed, 27 Nov 2019 15:48:30 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5614B21826; Wed, 27 Nov 2019 20:48:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887709; bh=EAxCQth2ZKk/kGjhKRAbSAUj7vT5Dv3HrY5a2a8j1CI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YhrkKk5M/OB2V0V4AdCFChxov8MA5d+pEudIG081EBgb2cDgdCzUv0JNiUzboYdGW FOp+eoyIsHbo3iSoxHrIm7hq0XRp0t6rApG+SWum1gfi+ZTnBm1LS6RyzW9I7qjExn Y3lEhAaMiYVqZ3AdQhFSE3b8Tepv6z0Xq3+2wHck= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mattias Jacobsson <2pi@mok.nu>, Sasha Levin Subject: [PATCH 4.14 065/211] USB: misc: appledisplay: fix backlight update_status return code Date: Wed, 27 Nov 2019 21:29:58 +0100 Message-Id: <20191127203100.066967396@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191127203049.431810767@linuxfoundation.org> References: <20191127203049.431810767@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mattias Jacobsson <2pi@mok.nu> [ Upstream commit 090158555ff8d194a98616034100b16697dd80d0 ] Upon success the update_status handler returns a positive number corresponding to the number of bytes transferred by usb_control_msg. However the return code of the update_status handler should indicate if an error occurred(negative) or how many bytes of the user's input to sysfs that was consumed. Return code zero indicates all bytes were consumed. The bug can for example result in the update_status handler being called twice, the second time with only the "unconsumed" part of the user's input to sysfs. Effectively setting an incorrect brightness. Change the update_status handler to return zero for all successful transactions and forward usb_control_msg's error code upon failure. Signed-off-by: Mattias Jacobsson <2pi@mok.nu> Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/misc/appledisplay.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/usb/misc/appledisplay.c b/drivers/usb/misc/appledisplay.c index 03be7c75c5be7..3b59eaf81eefc 100644 --- a/drivers/usb/misc/appledisplay.c +++ b/drivers/usb/misc/appledisplay.c @@ -160,8 +160,11 @@ static int appledisplay_bl_update_status(struct backlight_device *bd) pdata->msgdata, 2, ACD_USB_TIMEOUT); mutex_unlock(&pdata->sysfslock); - - return retval; + + if (retval < 0) + return retval; + else + return 0; } static int appledisplay_bl_get_brightness(struct backlight_device *bd) -- 2.20.1