From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CFA431C2DA3; Tue, 27 Aug 2024 12:32:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724761926; cv=none; b=LSL83kd5wajnNuv5iHnQpbVBi29cUJ3RNaS0kyJmjknHrQYudx8txT87j8sHUe/9ow1OOxPyBm0pgwGpigcwg9SuILkk0VRmokDEKhJuEVnUJwaG7119iFsnPEiHcCd5ALYT71koAHc0XrNpeLKUtwaZqm4ULNJXQ+hdNW4JR74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724761926; c=relaxed/simple; bh=Wm/BkMezv2xCJOsSmzbRpJVXjxQ8zUW0dbYK/XHmGEE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=DMxOvpoJWaRJUT+ZRutnkXi2+dQs05rcn6KJ4LIYYF7mA7wOWYICI/23raJIqX1ROIjb3wu2BJPTUJeKo0n7mFveaZDX/xjGuLZbamF04oPaGf03wWDlAK8ZGBCChuK4sLRc/PGYzfO0maKObavYROvYm6eP2ploaLxsM5eDEg8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: 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