From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH 16/33] powerpc/powernv: remove dead npu-dma code Date: Mon, 15 Oct 2018 13:45:26 +1100 Message-ID: References: <20181009132500.17643-1-hch@lst.de> <20181009132500.17643-17-hch@lst.de> <7709932d-efb8-2c9b-5128-99cc491c302b@ozlabs.ru> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <7709932d-efb8-2c9b-5128-99cc491c302b-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Alexey Kardashevskiy , Christoph Hellwig , Paul Mackerras , Michael Ellerman Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-arch.vger.kernel.org On Mon, 2018-10-15 at 12:34 +1100, Alexey Kardashevskiy wrote: > On 10/10/2018 00:24, Christoph Hellwig wrote: > > This code has been unused since it was merged and is in the way of > > cleaning up the DMA code, thus remove it. > > > > This effectively reverts commit 5d2aa710 ("powerpc/powernv: Add support > > for Nvlink NPUs"). > > > This code is heavily used by the NVIDIA GPU driver. Some of it is, yes. And while I don't want to be involved in the discussion about that specific can of worms, there is code in this file related to the custom "always error" DMA ops that I suppose we could remove, which is what is getting in the way of Christoph cleanups. It's just meant as a debug stuff to catch incorrect attempts at doing the dma mappings on the wrong "side" of the GPU. Cheers, Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org ([63.228.1.57]:56988 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731280AbeLVSFh (ORCPT ); Sat, 22 Dec 2018 13:05:37 -0500 Message-ID: Subject: Re: [PATCH 16/33] powerpc/powernv: remove dead npu-dma code From: Benjamin Herrenschmidt Date: Mon, 15 Oct 2018 13:45:26 +1100 In-Reply-To: <7709932d-efb8-2c9b-5128-99cc491c302b@ozlabs.ru> References: <20181009132500.17643-1-hch@lst.de> <20181009132500.17643-17-hch@lst.de> <7709932d-efb8-2c9b-5128-99cc491c302b@ozlabs.ru> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Alexey Kardashevskiy , Christoph Hellwig , Paul Mackerras , Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <20181015024526.9ww3Qm7qHvgxJO4MRbRiU3FAltKQy5m-YKH7SfgmOJY@z> On Mon, 2018-10-15 at 12:34 +1100, Alexey Kardashevskiy wrote: > On 10/10/2018 00:24, Christoph Hellwig wrote: > > This code has been unused since it was merged and is in the way of > > cleaning up the DMA code, thus remove it. > > > > This effectively reverts commit 5d2aa710 ("powerpc/powernv: Add support > > for Nvlink NPUs"). > > > This code is heavily used by the NVIDIA GPU driver. Some of it is, yes. And while I don't want to be involved in the discussion about that specific can of worms, there is code in this file related to the custom "always error" DMA ops that I suppose we could remove, which is what is getting in the way of Christoph cleanups. It's just meant as a debug stuff to catch incorrect attempts at doing the dma mappings on the wrong "side" of the GPU. Cheers, Ben.