Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753846AbbKWQW5 (ORCPT ); Mon, 23 Nov 2015 11:22:57 -0500 Received: from mail-wm0-f53.google.com ([74.125.82.53]:33006 "EHLO mail-wm0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753515AbbKWQWy (ORCPT ); Mon, 23 Nov 2015 11:22:54 -0500 Date: Mon, 23 Nov 2015 16:22:49 +0000 From: Lee Jones To: Arnd Bergmann Cc: Jingoo Han , Michael Hennerich , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] backlight: adp88x0: fix uninitialized variable use Message-ID: <20151123162159.GC807@x1> References: <3850346.cL1ocQLBvP@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3850346.cL1ocQLBvP@wuerfel> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2918 Lines: 74 On Mon, 23 Nov 2015, Arnd Bergmann wrote: > gcc correctly warns about both the adp8860 and adp8870 backlight > drivers using an uninitialized variable in their error handling > path: > > drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store': > drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function > > This changes the code to only write back the data if it was > correctly read to start with. > > As a side-note, the drivers are mostly identical, so I think they > should really be merged into one file to avoid having to fix every > bug twice. > > Signed-off-by: Arnd Bergmann Applied with the $SUBJECT line fixed. > diff --git a/drivers/video/backlight/adp8860_bl.c b/drivers/video/backlight/adp8860_bl.c > index 98ffe71e8af2..f0d4c0324580 100644 > --- a/drivers/video/backlight/adp8860_bl.c > +++ b/drivers/video/backlight/adp8860_bl.c > @@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev, > > /* Set user supplied ambient light zone */ > mutex_lock(&data->lock); > - adp8860_read(data->client, ADP8860_CFGR, ®_val); > - reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT); > - reg_val |= (val - 1) << CFGR_BLV_SHIFT; > - adp8860_write(data->client, ADP8860_CFGR, reg_val); > + ret = adp8860_read(data->client, ADP8860_CFGR, ®_val); > + if (!ret) { > + reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT); > + reg_val |= (val - 1) << CFGR_BLV_SHIFT; > + adp8860_write(data->client, ADP8860_CFGR, reg_val); > + } > mutex_unlock(&data->lock); > } > > diff --git a/drivers/video/backlight/adp8870_bl.c b/drivers/video/backlight/adp8870_bl.c > index 9d738352d7d4..21acac90fd77 100644 > --- a/drivers/video/backlight/adp8870_bl.c > +++ b/drivers/video/backlight/adp8870_bl.c > @@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev, > > /* Set user supplied ambient light zone */ > mutex_lock(&data->lock); > - adp8870_read(data->client, ADP8870_CFGR, ®_val); > - reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT); > - reg_val |= (val - 1) << CFGR_BLV_SHIFT; > - adp8870_write(data->client, ADP8870_CFGR, reg_val); > + ret = adp8870_read(data->client, ADP8870_CFGR, ®_val); > + if (!ret) { > + reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT); > + reg_val |= (val - 1) << CFGR_BLV_SHIFT; > + adp8870_write(data->client, ADP8870_CFGR, reg_val); > + } > mutex_unlock(&data->lock); > } > > -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/