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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E8F44C54734 for ; Tue, 27 Aug 2024 13:53:35 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4WtTXZ4VpGz2yVV; Tue, 27 Aug 2024 23:53:34 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1724761960; cv=none; b=EIeu2pO6TshatW1j2EPN2Fv+1Dh86mvVdXmE8TWucFLPGTyVruyTOU2XyQTIK1i3juCBcqVXLnp3SES+oplakOJ72DvyiaJsVDYbk5kHlWoSTlYhkH1dAUrnEaCR0+RLBTtvv9KQBzVHrSf1AuR8R1v3HDqxAZD1XDQOd7YXQuBIlfZAZ7VZlXDQuzuJihgutx6ka+OcHwQqjnObkIbZMWTokLnOnnfR/i3pLopHERsLEEEp9UXlGa6lZVthxvPaEBvn2LBalRuQ/xQAXCYKoEOQI9r5B9CxT9ubU7QYC3hh0ICR5lRnMeSxak59SSy6sfga7+2UwnJvhLu76bPgsQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1724761960; c=relaxed/relaxed; bh=M9vEl6rF8ZxKCqQCsR80va83TXNgOvysJQ+FmjX+YOs=; h=Received:Received:Message-ID:Date:MIME-Version:User-Agent:Subject: To:Cc:References:From:Content-Language:In-Reply-To:Content-Type: Content-Transfer-Encoding; b=l9Hv6zPXGfqrWq8Z9KUQLQb3u0Oh3wKgll1a4VQQN39g1gl1/L2dmmsJLTYFHLezj4OiZXxpF5r4P891lkL2YpewlFEYK5iSy6Bgwfukw7lvMdrq2WdI5qbhncVoGA21One0HLELoLnuc7sak9MjuLoNwnsfGUbcU6B5L3ML9zx5WB4UTQmnfR8JV7/+Ij/rG1b9YOFl1A5ii791hhXGrFh1cJqd6/+vByADW9M34FKmi7frK9yuWIgpNe0lDDL0EIm40Exdfvk+yFefKmuRXuH4rJQ0Fdrt+0g0wniX9irgC6VGvsGMyy0lAQgG83ZWp3s/TCxuJzvU45Z7D5l0ig== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=robin.murphy@arm.com; receiver=lists.ozlabs.org) smtp.mailfrom=arm.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=robin.murphy@arm.com; receiver=lists.ozlabs.org) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4WtRlD0YBPz2xrk for ; Tue, 27 Aug 2024 22:32:37 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 69B28DA7; Tue, 27 Aug 2024 05:32:30 -0700 (PDT) Received: from [10.1.196.40] (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C67E53F762; Tue, 27 Aug 2024 05:32:01 -0700 (PDT) Message-ID: <91ef4036-6468-4ecc-ac14-0146130d8da4@arm.com> Date: Tue, 27 Aug 2024 13:31:59 +0100 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Post: List-Subscribe: , , List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] dma-mapping: clear mark DMA ops as an architecture feature To: Christoph Hellwig , iommu@lists.linux.dev Cc: Marek Szyprowski , Sakari Ailus , Bingbu Cao , "Michael S . Tsirkin" , Jason Wang , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-media@vger.kernel.org, virtualization@lists.linux.dev, xen-devel@lists.xenproject.org References: <20240824035817.1163502-1-hch@lst.de> <20240824035817.1163502-2-hch@lst.de> From: Robin Murphy Content-Language: en-GB In-Reply-To: <20240824035817.1163502-2-hch@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 24/08/2024 4:57 am, Christoph Hellwig wrote: > DMA ops are a helper for architectures and not for drivers to override > the DMA implementation. Unfortunately driver authors keep ignoring > this. Make this more clear by renaming the symbol to ARCH_DMA_OPS, > have the three drivers overriding it depend on that. They should > probably also be marked broken, but we can give them a bit of a grace > period for that. Nit: from a quick survey of "git grep 'select ARCH_'", maybe ARCH_HAS_DMA_OPS might be the clearest and most consistent name? Otherwise, now that any potential confusion from drivers/iommu is no more, I too thoroughly approve of the overall idea. Acked-by: Robin Murphy