From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992479AbaEPTbu (ORCPT ); Fri, 16 May 2014 15:31:50 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:54825 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992428AbaEPTbt (ORCPT ); Fri, 16 May 2014 15:31:49 -0400 Date: Fri, 16 May 2014 21:31:39 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: walter harms Cc: Emil Goode , Shawn Guo , Sascha Hauer , Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH v2] ARM: imx: fix error handling Message-ID: <20140516193139.GQ16662@pengutronix.de> References: <1400234045-6022-1-git-send-email-emilgoode@gmail.com> <5375EB13.8000200@bfs.de> <20140516111646.GC4366@lianli> <5375FB36.8020004@bfs.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5375FB36.8020004@bfs.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:5054:ff:fec0:8e10 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Walter, On Fri, May 16, 2014 at 01:49:10PM +0200, walter harms wrote: > Am 16.05.2014 13:16, schrieb Emil Goode: > > Hello Walter, > > > > On Fri, May 16, 2014 at 12:40:19PM +0200, walter harms wrote: > >> > >> > >> Am 16.05.2014 11:54, schrieb Emil Goode: > >>> If we fail to allocate struct platform_device pdev we > >>> dereference it after the goto label err. > >>> > >>> I have rearranged the error handling a bit to fix the issue > >>> and also make it more clear. > >>> > >>> Signed-off-by: Emil Goode > >>> --- > >>> v2: Changed to return -ENOMEM instead of ret where possible and > >>> updated the subject line. > >>> > >>> arch/arm/mach-imx/devices/platform-ipu-core.c | 22 +++++++++++++--------- > >>> 1 file changed, 13 insertions(+), 9 deletions(-) > >>> > >>> diff --git a/arch/arm/mach-imx/devices/platform-ipu-core.c b/arch/arm/mach-imx/devices/platform-ipu-core.c > >>> index fc4dd7c..68f2a4a 100644 > >>> --- a/arch/arm/mach-imx/devices/platform-ipu-core.c > >>> +++ b/arch/arm/mach-imx/devices/platform-ipu-core.c > >>> @@ -77,34 +77,38 @@ struct platform_device *__init imx_alloc_mx3_camera( > >>> > >>> pdev = platform_device_alloc("mx3-camera", 0); > >>> if (!pdev) > >>> - goto err; > >>> + return ERR_PTR(-ENOMEM); > >>> > >>> pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL); > >>> if (!pdev->dev.dma_mask) > >>> - goto err; > >>> + goto put_pdev; > >>> > >>> *pdev->dev.dma_mask = DMA_BIT_MASK(32); > >>> pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); > >>> > >>> ret = platform_device_add_resources(pdev, res, ARRAY_SIZE(res)); > >>> if (ret) > >>> - goto err; > >>> + goto free_dma_mask; > >>> > >>> if (pdata) { > >>> struct mx3_camera_pdata *copied_pdata; > >>> > >>> ret = platform_device_add_data(pdev, pdata, sizeof(*pdata)); > >>> - if (ret) { > >>> -err: > >>> - kfree(pdev->dev.dma_mask); > >>> - platform_device_put(pdev); > >>> - return ERR_PTR(-ENODEV); > >>> - } > >>> + if (ret) > >>> + goto free_dma_mask; > >>> + > >>> copied_pdata = dev_get_platdata(&pdev->dev); > >>> copied_pdata->dma_dev = &imx_ipu_coredev->dev; > >> > >> > >> the patch is fine, but what use is this copied_pdata ? > >> It scope ends next line ? > >> > >> re, > >> wh > > > > I also thought that looked a bit odd, but copied_pdata is a temporary > > pointer to platform_data of the dev struct. > > > > dev_get_platdata looks like this: > > > > static inline void *dev_get_platdata(const struct device *dev) > > { > > return dev->platform_data; > > } > > > > So I believe it's a more compact way of writing: > > > > pdev->dev->platform_data->dma_dev = &imx_ipu_coredev->dev; It's not about compactness. The dev_get_platdata accessor exists to be used instead of directly accessing dev->platform_data. I admit a comment would be nice ... Anyhow this is all ugly, actually you'd want to have the dma_dev member already fixed when calling platform_device_add_data. But you cannot simply do pdata->dma_dev = &imx_ipu_coredev->dev; ret = platform_device_add_data(pdev, pdata, sizeof(*pdata)); because *pdata is const. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |