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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04987C433EF for ; Wed, 29 Jun 2022 00:14:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229740AbiF2AOz (ORCPT ); Tue, 28 Jun 2022 20:14:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229490AbiF2AOx (ORCPT ); Tue, 28 Jun 2022 20:14:53 -0400 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C6C522516; Tue, 28 Jun 2022 17:14:52 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id o18so12546375plg.2; Tue, 28 Jun 2022 17:14:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language :from:to:cc:references:in-reply-to:content-transfer-encoding; bh=05ASLe35KlS/635AYkr9ttdQBevoBXGVkR7t9AbxzS8=; b=dzzx4WtXS/WkHpvykE0Ug4pI7IQoDYpxYcwT22eGTgXydtRyVau06KToMULz4WZ85p grc9sV1BmBI096bjPV6AYIg+FD5hBe5gj3092gLAqIoDR6Usno3qkCUxW0him8f4Kt+7 5Uf02V1S6CU9QXgRzjHroyahVKDiR/lHNsV044fz9JWOwGa1zg1AbzobwrAmZjbW8zFF NJWZj5bNSbN92/C5/1fpmT4IbOePFpLv8AN2psJq3YvTqAwnlZ6jrlyHQy1YHFlzFM4V 6GGIoWoQqCmV+YlWQVYdo/a8/uHvejllTjqLg43Sy9OxgGuiI2LvtGtvLWOWEwxpHjVI SvDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:from:to:cc:references:in-reply-to :content-transfer-encoding; bh=05ASLe35KlS/635AYkr9ttdQBevoBXGVkR7t9AbxzS8=; b=Vehktr0tLQ/RatkkMM7U7Ezp4A+PPnWPsGkhNKzqPNYTLYGCS7kgvqjJpmsA/mT7Zj yuvSRCJdX0rZ8jf8bltL227l5vJ5TnKH3BQLN2o9JdXK6z45ItHIN9QIlh8poaVXVOly LVfiDLKolykD+2394olkL8jBGXg/xczVDuQQqDzvgULle9V5d1O8q3IFOqpf4pDJGAvf uneGraK+opAVRalhv+KFTUXaNcaRz1rdaOiy6BDwk/F1u/KWbSHluPh4mn1bi2p4gOrh wf/VWgnZJ4l9pPskCDuV+LM2Qmp82QXwiHAvt0hW8NMHH0IO9O+QFRWdNeSrSjhMX/gF kFuw== X-Gm-Message-State: AJIora9K8YNA9F+SXHUMwVRNw/fqek8+4LScMtZBjYoRbWtTgOHTJ8xC bBLhSUjNLmVTB2HYDqVKA0A= X-Google-Smtp-Source: AGRyM1s6BvhKknOd3DGT0QQr5uB83fgcSZ645ndGItCzAFy4UPsuv2Gt9Oy4n8CrGTj/IyliMMkT6Q== X-Received: by 2002:a17:903:240e:b0:168:ea13:f9e0 with SMTP id e14-20020a170903240e00b00168ea13f9e0mr7684101plo.6.1656461692074; Tue, 28 Jun 2022 17:14:52 -0700 (PDT) Received: from ?IPV6:2001:df0:0:200c:75aa:d6ca:4354:6033? ([2001:df0:0:200c:75aa:d6ca:4354:6033]) by smtp.gmail.com with ESMTPSA id c13-20020a170902c1cd00b0016a276aada7sm9950167plc.20.2022.06.28.17.14.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 28 Jun 2022 17:14:51 -0700 (PDT) Message-ID: <2402062b-aae6-a247-06a8-3775c2909bdb@gmail.com> Date: Wed, 29 Jun 2022 12:14:42 +1200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v2 3/3] arch/*/: remove CONFIG_VIRT_TO_BUS Content-Language: en-US From: Michael Schmitz To: Bart Van Assche , Arnd Bergmann Cc: Geert Uytterhoeven , scsi , Linux Kernel Mailing List , Arnd Bergmann , Jakub Kicinski , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Linux IOMMU , Khalid Aziz , "Maciej W . Rozycki" , Matt Wang , Miquel van Smoorenburg , Mark Salyzyn , linuxppc-dev , Linux-Arch , alpha , linux-m68k , Parisc List , Denis Efremov , Michael Ellerman , John Paul Adrian Glaubitz References: <20220617125750.728590-1-arnd@kernel.org> <20220617125750.728590-4-arnd@kernel.org> <6ba86afe-bf9f-1aca-7af1-d0d348d75ffc@gmail.com> <9289fd82-285c-035f-5355-4d70ce4f87b0@gmail.com> <9f812d3d-0fcd-46e6-6d7e-6d4bf66f24ab@gmail.com> <859c2adc-d3cb-64e8-faba-06e1ac5eddaf@gmail.com> In-Reply-To: <859c2adc-d3cb-64e8-faba-06e1ac5eddaf@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi Bart, On 29/06/22 12:01, Michael Schmitz wrote: > >> An example of a user space application that passes an SG I/O data >> buffer to the kernel that is aligned to a four byte boundary but not >> to an eight byte boundary if the -s (scattered) command line option >> is used: >> https://github.com/osandov/blktests/blob/master/src/discontiguous-io.cpp > > Thanks - four byte alignment actually wouldn't be an issue for me. > It's two byte or smaller that would trip up the SCSI DMA. > > While I'm sure such an even more pathological test case could be > written, I was rather worried about st.c and sr.c input ... Nevermind - I just see m68k defines ARCH_DMA_MINALIGN to be four bytes. Should be safe for all that matters, then. Cheers,     Michael