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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1DC01CA1002 for ; Sun, 31 Aug 2025 13:13:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 04CE08E0002; Sun, 31 Aug 2025 09:13:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F3F558E0001; Sun, 31 Aug 2025 09:12:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E2E008E0002; Sun, 31 Aug 2025 09:12:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id C947F8E0001 for ; Sun, 31 Aug 2025 09:12:59 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 5A1791199D8 for ; Sun, 31 Aug 2025 13:12:59 +0000 (UTC) X-FDA: 83837092878.29.4712BCA Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf19.hostedemail.com (Postfix) with ESMTP id E272F1A0002 for ; Sun, 31 Aug 2025 13:12:57 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=WMN3gtSJ; spf=pass (imf19.hostedemail.com: domain of leon@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=leon@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756645978; a=rsa-sha256; cv=none; b=xawKsVdqt5fcYR80H5FkgHD6u1RsRf2/+5Lh80snpr9PrH/o0dujsBV3CMaWREKmWs44dC DyYns3TnFYQOkCSJ4adq1swjTYhtddfDCgNLCC5ht8vKMGVvTqPvpY2Tzvj9bO4I/W3qJz 2Mpz8nU5rgPIijio+aGoCpupqp/iB0Q= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=WMN3gtSJ; spf=pass (imf19.hostedemail.com: domain of leon@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=leon@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756645978; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ac+Ch9BPhurz6Qm+wFXw5b045ua0/xnlchZZPlAlRmQ=; b=uT2JuBj5S6GbNgsi2A4ZlXff2CNoFS9xpz7qLnWcmaI1gCRHma6hjlgBGirEj4flkGS5m+ 7fy5o9WBruKCUF8jAaWh8z//XnNXObyOpdH80IU/Iu8xn8zXm1iBi1Sw6e9KvF7jIKrEKn iyA1+DbXz3/2+l5nr0vqVO22uwiHHcc= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id D1202601AF; Sun, 31 Aug 2025 13:12:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB2B1C4CEED; Sun, 31 Aug 2025 13:12:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756645976; bh=SVfffytdJ7l+FJFH+NQ2fAYz/jln+XvhXnCAv4vVciA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WMN3gtSJVf7yZJvH25PHoup176xzR4iH45PFd5WTaZl3P3yIlcpIRkfu5U3ulpn36 IKubxjRKitiVH7tEFGk0EvSWGehRo+3Ze6ErmIyU4uPo4HQlYX4MxtypCD8fFWeHBM x5lx5bK4qJ+D+MLZSAMBnr8/dS6PtN2tAd1/pTiMLV/guQAHue805z1yqYSMaGWuq1 Airln6Bzle28Ohk7U9LgDEafLkaTwO2O0iuzeLmhUWu5F6SgZbC5gh8KCCHy3wqp2C Hcv7g6EwqE5WnoDtEeiWuc9ndJyrHz9MWyHpBWe4DPcTvzNQTROEZWINBtgECoxCxA rqMaDKHjRKGlQ== Date: Sun, 31 Aug 2025 16:12:50 +0300 From: Leon Romanovsky To: Jason Gunthorpe Cc: Marek Szyprowski , Abdiel Janulgue , Alexander Potapenko , Alex Gaynor , Andrew Morton , Christoph Hellwig , Danilo Krummrich , iommu@lists.linux.dev, Jason Wang , Jens Axboe , Joerg Roedel , Jonathan Corbet , Juergen Gross , kasan-dev@googlegroups.com, Keith Busch , linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvme@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-trace-kernel@vger.kernel.org, Madhavan Srinivasan , Masami Hiramatsu , Michael Ellerman , "Michael S. Tsirkin" , Miguel Ojeda , Robin Murphy , rust-for-linux@vger.kernel.org, Sagi Grimberg , Stefano Stabellini , Steven Rostedt , virtualization@lists.linux.dev, Will Deacon , xen-devel@lists.xenproject.org Subject: Re: [PATCH v4 09/16] dma-mapping: handle MMIO flow in dma_map|unmap_page Message-ID: <20250831131250.GC10073@unreal> References: <20250828151730.GH9469@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250828151730.GH9469@nvidia.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: E272F1A0002 X-Stat-Signature: kimztmjz6c5zbiuhjhh3z5k1jrjwt8fj X-Rspam-User: X-HE-Tag: 1756645977-739178 X-HE-Meta: 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 phC438Ug RcL3BE4nZdxAlH40XbLLcR30fAY91sVUAjCFJJb033R6q1pVxR0C/qDR75X3hwCrdW7cQHIGwPLCfW2M= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 28, 2025 at 12:17:30PM -0300, Jason Gunthorpe wrote: > On Tue, Aug 19, 2025 at 08:36:53PM +0300, Leon Romanovsky wrote: > > From: Leon Romanovsky > > > > Extend base DMA page API to handle MMIO flow and follow > > existing dma_map_resource() implementation to rely on dma_map_direct() > > only to take DMA direct path. > > I would reword this a little bit too > > dma-mapping: implement DMA_ATTR_MMIO for dma_(un)map_page_attrs() > > Make dma_map_page_attrs() and dma_map_page_attrs() respect > DMA_ATTR_MMIO. > > DMA_ATR_MMIO makes the functions behave the same as dma_(un)map_resource(): > - No swiotlb is possible > - Legacy dma_ops arches use ops->map_resource() > - No kmsan > - No arch_dma_map_phys_direct() > > The prior patches have made the internl funtions called here support > DMA_ATTR_MMIO. > > This is also preparation for turning dma_map_resource() into an inline > calling dma_map_phys(DMA_ATTR_MMIO) to consolidate the flows. > > > @@ -166,14 +167,25 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, > > return DMA_MAPPING_ERROR; > > > > if (dma_map_direct(dev, ops) || > > - arch_dma_map_phys_direct(dev, phys + size)) > > + (!is_mmio && arch_dma_map_phys_direct(dev, phys + size))) > > addr = dma_direct_map_phys(dev, phys, size, dir, attrs); > > PPC is the only user of arch_dma_map_phys_direct() and it looks like > it should be called on MMIO memory. Seems like another inconsistency > with map_resource. I'd leave it like the above though for this series. > > > else if (use_dma_iommu(dev)) > > addr = iommu_dma_map_phys(dev, phys, size, dir, attrs); > > - else > > + else if (is_mmio) { > > + if (!ops->map_resource) > > + return DMA_MAPPING_ERROR; > > Probably written like: > > if (ops->map_resource) > addr = ops->map_resource(dev, phys, size, dir, attrs); > else > addr = DMA_MAPPING_ERROR; I'm big fan of "if (!ops->map_resource)" coding style and prefer to keep it. > > As I think some of the design here is to run the trace even on the > failure path? Yes, this is how it worked before. > > Otherwise looks OK > > Reviewed-by: Jason Gunthorpe > > Jason