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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 199E0C54735 for ; Tue, 27 Aug 2024 12:38:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=M9vEl6rF8ZxKCqQCsR80va83TXNgOvysJQ+FmjX+YOs=; b=t8hvINyEHTYIbk/WZWRzpgn9To /kdzUeUkPtD8xCKyp2tOGu33elm1eSTd4WprQphfkgrnt5yF3FFxh2syOaOAl5MHsOks3UeddN3ny UD/LtA0LWztNaF760CfjgXfRjeSL8beVQMKvc198lF3P4H0YPIGjzxDLzmtyfBVFNZGqYhmh0lNxq 9ksP6F47llQf+/2fF12h+9vaLxDyRnVijkC+F9W2RnHW0JkG3znW6eArrYtxcwBRcwrFAb566ewKo rCMkVW8D5Sn1yhLB+bwkRpGke9M3gUgcg/HMEjaWECHyYJhMGMHhn6REDGT0K7WQOYLPMBR8/8Iop VU30vnhA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sivTE-0000000BHN4-0OU6; Tue, 27 Aug 2024 12:38:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sivMj-0000000BFF4-2HX5 for linux-arm-kernel@lists.infradead.org; Tue, 27 Aug 2024 12:32:07 +0000 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240827_053205_836353_BA9A8D2E X-CRM114-Status: UNSURE ( 8.57 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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