From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id 220B5AD5B; Sat, 24 Aug 2024 03:58:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724471904; cv=none; b=mmm9v2LrxPlUCXh8QmSTPi4gOdIkCyYEnQJjWotPlkj8268ATWGWrD2xNUU/4hVWvQ54sy2HuVVqvzMwgc0a1oprPXPYT3VTdiFpmfpz86NVO5NSmRcavolHjhWK25epQOFTbHODNDEPLh1/tJGzySVf0ceM4puIqh27C47OIgY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724471904; c=relaxed/simple; bh=Clh9AkGSwfDfUvvLJoxosPbut7uF7iTtgQ3zxQUr6Og=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Rc6vJmSscuYCzYnqqgSMszH9rraTYuBSVm2DVHDOr45qdE2v8Hr/wnXALc8rncza9QwHaOJTrzhx49YuqJb1KWYvRgpQ8vhJ4tZeDPMTY75Q/CF+QlqmUv4dIT2EAscu1KcC3SkDx62axkdamU6JyIf4bT9FooIj6G08e0zjD0k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ibODa9lL; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ibODa9lL" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:In-Reply-To:References; bh=Q2nYRi9U4a8itDtDq9LNnEMZ/Twd4vEjX9CTeiWFtZk=; b=ibODa9lL5q7uggEbw2OOQZkuOl gdhQY0r9D/9beDb+Bd4qmVTCvwI+QiMjo95/+tPj+4V9U7F5hRFToRdX4k4DvPYHu1OLEHcIx+etT KIlSwzlSzvMKbYOerqEj9me07yLSDIeP/0/bbrlY9qqah4ekXhqi/eYjBvvldU6VljO5zLO6djC2Z 2yksa1axP4sCcbZUGAWwKgEmbBGoAFPkoBoCxdpgqo5+6g1QWpb94Ilm4RmYcg8FZcggX2U6K6Sfe cGdem+9zPaemNy7/Cr0ZBWXuCzcsmrGl8tEN+ptWMeKG1q46THZ+VeovOI19ardMWa1DQRk/ZtOsI ioZS20vQ==; Received: from 2a02-8389-2341-5b80-7457-864c-9b77-b751.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:7457:864c:9b77:b751] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1shhut-00000001ON7-0bmD; Sat, 24 Aug 2024 03:58:20 +0000 From: Christoph Hellwig To: iommu@lists.linux.dev Cc: Marek Szyprowski , Robin Murphy , 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 Subject: clearly mark DMA_OPS support as an architecture feasture Date: Sat, 24 Aug 2024 05:57:57 +0200 Message-ID: <20240824035817.1163502-1-hch@lst.de> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Hi all, we've had a long standing problems where drivers try to hook into the DMA_OPS mechanisms to override them for something that is not DMA, or to introduce additional dispatching. Now that we are not using DMA_OPS support for dma-iommu and can build kernels without DMA_OPS support on many common setups this becomes even more problematic. This series renames the option to ARCH_DMA_OPS and adds very explicit comment to not use it in drivers. The ipu6 and vdpa_sim/user drivers that abuse the mechanism are made to depend on the option instead of selecting it with a big comment, but I expect this to be fixed rather sooner than later (I know the ipu6 maintainers are on it based on a previous discussion).