From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBD60CA9ECB for ; Wed, 30 Oct 2019 22:38:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CADD320856 for ; Wed, 30 Oct 2019 22:38:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727381AbfJ3WiV (ORCPT ); Wed, 30 Oct 2019 18:38:21 -0400 Received: from verein.lst.de ([213.95.11.211]:48074 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726377AbfJ3WiV (ORCPT ); Wed, 30 Oct 2019 18:38:21 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id B09CA68B05; Wed, 30 Oct 2019 23:38:18 +0100 (CET) Date: Wed, 30 Oct 2019 23:38:18 +0100 From: Christoph Hellwig To: Thomas Bogendoerfer Cc: Christoph Hellwig , "David S. Miller" , linux-mips@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls Message-ID: <20191030223818.GA23807@lst.de> References: <20191030211233.30157-1-hch@lst.de> <20191030211233.30157-2-hch@lst.de> <20191030230549.ef9b99b5d36b0a818d904eee@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191030230549.ef9b99b5d36b0a818d904eee@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 30, 2019 at 11:05:49PM +0100, Thomas Bogendoerfer wrote: > On Wed, 30 Oct 2019 14:12:30 -0700 > Christoph Hellwig wrote: > > > dma_direct_ is a low-level API that must never be used by drivers > > directly. Switch to use the proper DMA API instead. > > is the 4kb/16kb alignment still guaranteed ? If not how is the way > to get such an alignment ? The DMA API gives you page aligned memory. dma_direct doesn't give you any gurantees as it is an internal API explicitly documented as not for driver usage that can change at any time.