From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1423113AbcFMQzz (ORCPT <rfc822;w@1wt.eu>);
	Mon, 13 Jun 2016 12:55:55 -0400
Received: from mga03.intel.com ([134.134.136.65]:28737 "EHLO mga03.intel.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1423067AbcFMQzt (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Mon, 13 Jun 2016 12:55:49 -0400
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.26,467,1459839600"; 
   d="scan'208";a="996711311"
Date: Mon, 13 Jun 2016 22:32:29 +0530
From: Vinod Koul <vinod.koul@intel.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Williams <dan.j.williams@intel.com>,
        Michal Simek <michal.simek@xilinx.com>,
        =?iso-8859-1?Q?S=F6ren?= Brinkmann <soren.brinkmann@xilinx.com>,
        Kedareswara rao Appana <appana.durga.rao@xilinx.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dma: xilinx-vdma: add some sanity checks
Message-ID: <20160613170229.GJ16910@localhost>
References: <1465830523-2484498-1-git-send-email-arnd@arndb.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1465830523-2484498-1-git-send-email-arnd@arndb.de>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Jun 13, 2016 at 05:07:33PM +0200, Arnd Bergmann wrote:
> The newly added xilinx_dma_prep_dma_cyclic function sometimes causes
> a gcc warning about the use of the segment function in case
> we never run into the inner loop of the function:
> 
> dma/xilinx/xilinx_vdma.c: In function 'xilinx_dma_prep_dma_cyclic':
> dma/xilinx/xilinx_vdma.c:1808:23: error: 'segment' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>    segment->hw.control |= XILINX_DMA_BD_SOP;
> 
> This can only happen if the period len is zero (which would cause other
> problems earlier), or if the buffer is shorter than a period. Neither
> of them should ever happen, but by adding an explicit check for these two
> cases, we can abort in a more controlled way, and the compiler is
> able to see that we never use uninitialized data.

Applied after fixing subsystem name

Thanks
-- 
~Vinod