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.