From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by kanga.kvack.org (Postfix) with ESMTP id E9FCA6B4D9B for ; Wed, 28 Nov 2018 10:55:53 -0500 (EST) Received: by mail-wm1-f72.google.com with SMTP id o63-v6so2979222wma.2 for ; Wed, 28 Nov 2018 07:55:53 -0800 (PST) Received: from mo6-p01-ob.smtp.rzone.de (mo6-p01-ob.smtp.rzone.de. [2a01:238:20a:202:5301::10]) by mx.google.com with ESMTPS id y3-v6si2552174wmg.193.2018.11.28.07.55.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 28 Nov 2018 07:55:52 -0800 (PST) Subject: Re: use generic DMA mapping code in powerpc V4 References: <20181114082314.8965-1-hch@lst.de> <20181127074253.GB30186@lst.de> <87zhttfonk.fsf@concordia.ellerman.id.au> From: Christian Zigotzky Message-ID: <535776df-dea3-eb26-6bf3-83f225e977df@xenosoft.de> Date: Wed, 28 Nov 2018 16:55:30 +0100 MIME-Version: 1.0 In-Reply-To: <87zhttfonk.fsf@concordia.ellerman.id.au> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: de-DE Sender: owner-linux-mm@kvack.org List-ID: To: Michael Ellerman , Christoph Hellwig , Benjamin Herrenschmidt , Paul Mackerras Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org 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. I am also worried about this code. How can I test this new DMA mapping code? Thanks