From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752220AbeCOMyH (ORCPT ); Thu, 15 Mar 2018 08:54:07 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:53327 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751977AbeCOMyF (ORCPT ); Thu, 15 Mar 2018 08:54:05 -0400 Date: Thu, 15 Mar 2018 13:53:52 +0100 (CET) From: Thomas Gleixner To: Christoph Hellwig cc: x86@kernel.org, Konrad Rzeszutek Wilk , Tom Lendacky , David Woodhouse , Muli Ben-Yehuda , Jon Mason , Joerg Roedel , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/14] x86: use dma-direct In-Reply-To: <20180315115348.GA16210@lst.de> Message-ID: References: <20180314175213.20256-1-hch@lst.de> <20180314175213.20256-4-hch@lst.de> <20180315115348.GA16210@lst.de> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-1111037880-1521118432=:1525" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1111037880-1521118432=:1525 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT On Thu, 15 Mar 2018, Christoph Hellwig wrote: > On Thu, Mar 15, 2018 at 09:56:13AM +0100, Thomas Gleixner wrote: > > On Wed, 14 Mar 2018, Christoph Hellwig wrote: > > > > > The generic dma-direct implementation is now functionally equivalent to > > > the x86 nommu dma_map implementation, so switch over to using it. > > > > Can you please convert the various drivers first and then remove the > > unused code? > > Which various drivers? > > > > Note that the various iommu drivers are switched from x86_dma_supported The various iommu drivers .... > > > to dma_direct_supported to provide identical functionality, although the > > > checks looks fairly questionable for at least some of them. > > > > Can you please elaborate? From the above it's not clear which checks you > > are referring to. If you convert these drivers seperately then explicit > > information about your concerns wants to be in the changelogs. > > This bit: > > /* Copied from i386. Doesn't make much sense, because it will > only work for pci_alloc_coherent. > The caller just has to use GFP_DMA in this case. */ > if (mask < DMA_BIT_MASK(24)) > return 0; > > in x86_dma_supported, or the equivalent bit in dma_direct_supported. > Kept for bug to bug compatibility, but I guess I should reword or > just drop the changelog bit іf it causes confusion. Reword please. Thanks, tglx --8323329-1111037880-1521118432=:1525--