Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp1638093imu; Wed, 28 Nov 2018 12:36:21 -0800 (PST) X-Google-Smtp-Source: AFSGD/V0kmGY3Nf1Hy9hi/hZVDgF06NZ1nhWgEhET3p6QkMC6DUZro/5TbbZxPtuyjkQXiTYtq6c X-Received: by 2002:a63:4f5e:: with SMTP id p30mr34407887pgl.71.1543437381847; Wed, 28 Nov 2018 12:36:21 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1543437381; cv=none; d=google.com; s=arc-20160816; b=AxuO3PhGOZij97apUAk26xzYjvUznfb8AJdDEoLQ9CvekIrQp/54BA1a2uVmk2DXPv NQWsqPc2r7EfoBfwvT6MD9JFK34lGj76gT5feEHtmALbgVkDWgjBwEysceqpykp9urPh jsaxJHdbovvc9GMxE7QLeATV+CSBNQhYhAmBmu8OSFNsFTkO6Z6a+8k1VFn1q4fpagnP 4qIRv0mxPlNec6U798WEI5DLXObeHGI8qbqCHXSC6qO1k0HBU0SBgOx9QFAbQYijv5FE h3ljPuApOF113vqBDNXWqq/k7BQeuF5Jt1W+ne/Gjot8/QGUmBzKL+l28L8WR10ChYqG 7q0A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :organization:references:in-reply-to:message-id:subject:cc:to:from :date; bh=/32g/aEXS1ymrII+r4DWv/1hLS+1zBbeZoeBEuAGadM=; b=zctcWjrENHk+ZhyKxQ8T4bBwiEfyB4pFZ0/l91ZiTG7Zt9lzhOwtNxGBR/bs8j1mbb l6hPx4Ry9WJJgqv5eiRgNNt9x4nPBKXSC+g34y0+tNzxrXgd4EFGEfTxXCtHcVCggTL0 dLmD6I/rgWlUZSyWDNs7DAT+OOFXq1Z/Qd0RuZO5Kt7ClL/0D4BM4nOgz5oWz+bFeZTC KZMJgWy+E9dFbAYsVpJBGP89Bgfist140M1ZVlfiVty/aEsVK5m5Z/DIhcnkAJ0Gso4a DlcmtWu2PtZx9D6r0ZZWBmZlnQQd79tAfyHNTEEKn+NJCp3kbn122T+4hoz3zXvHZcJx RRcg== 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 f16si7795405pgb.140.2018.11.28.12.36.06; Wed, 28 Nov 2018 12:36:21 -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 S1726393AbeK2HiG (ORCPT + 99 others); Thu, 29 Nov 2018 02:38:06 -0500 Received: from mx2.suse.de ([195.135.220.15]:60460 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725799AbeK2HiG (ORCPT ); Thu, 29 Nov 2018 02:38:06 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 44BE6AC24; Wed, 28 Nov 2018 20:35:11 +0000 (UTC) Date: Wed, 28 Nov 2018 21:35:10 +0100 From: Michal =?UTF-8?B?U3VjaMOhbmVr?= To: Christian Zigotzky Cc: 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: <20181128213510.543259e3@kitsune.suse.cz> In-Reply-To: <535776df-dea3-eb26-6bf3-83f225e977df@xenosoft.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> Organization: SUSE Linux X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.31; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 28 Nov 2018 16:55:30 +0100 Christian Zigotzky wrote: > On 28 November 2018 at 12:05PM, Michael Ellerman wrote: > > Nothing specific yet. > > > > I'm a bit worried it might break one of the many old obscure platforms > > we have that aren't well tested. > > > 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. > I am also worried about this code. How > can I test this new DMA mapping code? I suppose if your machine works it works for you. Thanks Michal