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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 96284C432C3 for ; Sat, 16 Nov 2019 15:58:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6323221479 for ; Sat, 16 Nov 2019 15:58:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919936; bh=GQdssR5vvChor4Ev4t2/5349FPN4oSbrjLFcBctu+Y0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DjCIOT/sBytffyTEHvQf08AGEKxNdFji+5I6t2/NQS0XNbW6bnvJF/5s/yWEZLNNY j4W/gft8MU5YEVo9dTcVNlQLa3kWCVWHLLVbkkCaB7EU5vJ1z60aYy+IgziKmfwgIc +9meid5htB5vIG2L51tuEF53iaGZAnaaoOlf1iKc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731272AbfKPP6z (ORCPT ); Sat, 16 Nov 2019 10:58:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:35732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731400AbfKPPyM (ORCPT ); Sat, 16 Nov 2019 10:54:12 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 44B8021823; Sat, 16 Nov 2019 15:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919651; bh=GQdssR5vvChor4Ev4t2/5349FPN4oSbrjLFcBctu+Y0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e1FIfzQAL6DlPjyoV3cWx6ZgXxwCqASmh1K39yIRai3Fg4qJqiYW/3z8xNYnKvi+3 Z6oFDu2im9abFem9LD09yOTjBiDObnLYJkZo/r9ziYGjypge3XKA8iQ2qcBzz3qsg0 sGCO1xIU6waAVFHWRT4g/3O3sPM9YOI5ZSRxeTAY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mattias Jacobsson <2pi@mok.nu>, Greg Kroah-Hartman , Sasha Levin , linux-usb@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 26/77] USB: misc: appledisplay: fix backlight update_status return code Date: Sat, 16 Nov 2019 10:52:48 -0500 Message-Id: <20191116155339.11909-26-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116155339.11909-1-sashal@kernel.org> References: <20191116155339.11909-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@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 993f4da065c3a..dabd1077d03c4 100644 --- a/drivers/usb/misc/appledisplay.c +++ b/drivers/usb/misc/appledisplay.c @@ -161,8 +161,11 @@ 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