Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp2814799imu; Thu, 29 Nov 2018 10:38:51 -0800 (PST) X-Google-Smtp-Source: AFSGD/Ui8Izah9lcGRvFN0dtok5GulOSYOcWSiQ+GHdTjdolulSfRKCuZEnmrKYGKFw9N+hspxLZ X-Received: by 2002:a17:902:b595:: with SMTP id a21mr2466285pls.120.1543516731398; Thu, 29 Nov 2018 10:38:51 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1543516731; cv=none; d=google.com; s=arc-20160816; b=lB+fR5rNKXzs0NO4XdPkrVAt2KMFZN7ebLxapnMkRDUAf3na7JI71ePFN9Jb9i0SnN vSE/LbjF3ynrdheXrpJHkIV+HhgcTiHdSARRebUeJULDtW0GqeSb91REIM/RdP62jjHi rIBNzTHb2pvQOQhXRoPToHTyTxFf93ial3QzIkU6vsBSH/3GfBR2BekcQ8qaQIGRQ+GI Vq5tgn+wltPFEkrkzMslF4C1UaipplgQB6fxdpOGokuhJynA3lsgjQ062BRkncyNZ5GE eJVWholztAjTXeRGww/Nq7dzegVcyBPCM+C5GkOrnEPWsqYJgpWqkxfGtzbiHai7WHXU /RyA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=TDj7OKVb9oPIbMw73Mp8SnCgr29gycXgxKs8uGXoloM=; b=b8uzwEUWSPjEZJGTaQ61trbJWhVzkh540/qIXnC4C6W+bvyISsLLuZXW6Lq3dHSm8m t8J3aqHJhuVJB5t1NuyaAddgkRyZtoKQThoT8Bs+e5mn73G+UyNL/Gj41GkC6MdIByfd kFRiDry7XfNE2yzg8k7r2MIWlmeBE/Az0kdwLxXRA0iSEXjGopREIijeEGw0wZrWibz6 EnhLURT7z0R9lHYiYrEmxGj+RKiUpqjwy+d0360IfaHa3xgc4IY+UXeS6dR7lzr5RcYn 2jCQLu6aXbCU/378JS+HwSb1Cd1ltkHatYx6h7sy2VO28yMMF1HMx+93XG2kFxUCIqhX wChw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id d2-v6si2823329pla.140.2018.11.29.10.38.36; Thu, 29 Nov 2018 10:38:51 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730353AbeK3EJG (ORCPT + 99 others); Thu, 29 Nov 2018 23:09:06 -0500 Received: from verein.lst.de ([213.95.11.211]:44733 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729818AbeK3EJG (ORCPT ); Thu, 29 Nov 2018 23:09:06 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id 7C1EC68B02; Thu, 29 Nov 2018 18:03:02 +0100 (CET) Date: Thu, 29 Nov 2018 18:03:02 +0100 From: Christoph Hellwig To: Michal =?iso-8859-1?Q?Such=E1nek?= Cc: Christian Zigotzky , Michael Ellerman , Christoph Hellwig , Benjamin Herrenschmidt , Paul Mackerras , linux-arch@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: use generic DMA mapping code in powerpc V4 Message-ID: <20181129170302.GB27951@lst.de> References: <20181114082314.8965-1-hch@lst.de> <20181127074253.GB30186@lst.de> <87zhttfonk.fsf@concordia.ellerman.id.au> <535776df-dea3-eb26-6bf3-83f225e977df@xenosoft.de> <20181128213510.543259e3@kitsune.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181128213510.543259e3@kitsune.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Please don't apply the new DMA mapping code if you don't be sure if it > > works on all supported PowerPC machines. Is the new DMA mapping code > > really necessary? It's not really nice, to rewrote code if the old code > > works perfect. We must not forget, that we work for the end users. Does > > the end user have advantages with this new code? Is it faster? The old > > code works without any problems. > > There is another service provided to the users as well: new code that is > cleaner and simpler which allows easier bug fixes and new features. > Without being familiar with the DMA mapping code I cannot really say if > that's the case here. Yes, the main point is to move all architecturs to common code for the dma direct mapping code. This means we have one code bases that sees bugs fixed and features introduced the same way for everyone.