From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752337Ab3HAC1s (ORCPT ); Wed, 31 Jul 2013 22:27:48 -0400 Received: from mail-ob0-f169.google.com ([209.85.214.169]:62175 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751553Ab3HAC1r (ORCPT ); Wed, 31 Jul 2013 22:27:47 -0400 MIME-Version: 1.0 In-Reply-To: <20130729052930.GC29095@intel.com> References: <1371536519-7837-1-git-send-email-wangxfdu@gmail.com> <20130705064549.GD10947@intel.com> <20130729052930.GC29095@intel.com> Date: Thu, 1 Aug 2013 10:27:47 +0800 Message-ID: Subject: Re: [PATCH v2] dma: mmp_pdma: fix a memory alloc error From: Xiang Wang To: Vinod Koul Cc: Dan Williams , "linux-kernel@vger.kernel.org" , cxie4@marvell.com, Xiang Wang Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2013/7/29 Vinod Koul : > On Thu, Jul 25, 2013 at 10:22:50AM +0800, Xiang Wang wrote: > > Btw its generally a good idea to remove the parts not required for further > discussion > >> Would you please explain a little more about why we should use >> GFP_NOWAIT here? This memory is not dedicated for DMA controller. Do >> we have special reasons to use GFP_NOWAIT? Thanks! > There are few reasons > - the dma requests can be triggered from atomic context > - so for above you can argue to use the GFP_ATOMIC and the guideline for dma > drivers [1] was discussed briefly > > ~Vinod > [1]: http://lkml.indiana.edu/hypermail/linux/kernel/0911.1/02316.html > > -- Hi, Vinod Thanks for your explanation. But want to double confirm with you that the memory alloc in my patch is in probe function, still need to use GFP_NOWAIT? Thanks! -- Regards, Xiang