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 3251FC8302D for ; Mon, 30 Jun 2025 13:38:51 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4bW6gs60Dvz2yhX; Mon, 30 Jun 2025 23:38:49 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=213.95.11.211 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1751290729; cv=none; b=EL6eXpHRVzTRm/VWhHQgQSe/BqRXxUykMKv8fY8owww9O01ocQ447Z7tMt6phqlvOU+QZigjrrcd/nGyuVuj9/6ESGGdtQDjVZTAQUqDZFDzyKp+V5ebWY1UmO8vftPalPmOpo5MnKgUr6jZK8NBwHjLFrSGpovYidt76rty/8tp7U4Z5COcG6KnrJt2pnm6QpnVLZbuk50g3vN6oZrrmwyhQKHZFGRAfNq8HpMcLUh59cL7xQghkQ/NhhPgGM2OTr1USoeiMdce/1dTmNhqfUKIhBalDf+sgIVMkb1ixqo+fbj/S1q5uhPWoVegAuNkF628iLnrL8DuxsjaATDbEg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1751290729; c=relaxed/relaxed; bh=9EB5M+oZCNFUrXucC6vFVumKTSV4tlIG2ltmQJJW9N4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CPgOS83f+AGAg2N0BQm9hi8raBjeBm0PGkiYoPIOfFurOYpD3gZrO6WoJNsvSoHIxrxjCSwkza5BTUUebm5mt2hNSoHuAGENM4oKerkcb/SxG/aHsbkGC/HFyAC5Faqo7U6lhr+cZU7MRa9RAdMoqWhg8iUoTdUMvPb0Nni+dxly6ax/AS/nTsb/I1KiNPBKgDFHoe3rnRIxq2qtfq1FN7WjCzqbxcVpW5mlzVtHlI2m4cxadawm/w68FDgCM/932b2MwT2pdhR2n9mlfSZ7mPwNLzDBczsLhs4ISWSZSQ2Y0iaA1c/wQjaZ2oaui1xdFJQT5zNMQ7ZrtKnC60W1ow== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=lists.ozlabs.org) smtp.mailfrom=lst.de Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=lists.ozlabs.org) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4bW6gr02spz2yft for ; Mon, 30 Jun 2025 23:38:46 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id BF34B227A88; Mon, 30 Jun 2025 15:38:39 +0200 (CEST) Date: Mon, 30 Jun 2025 15:38:39 +0200 From: Christoph Hellwig To: Leon Romanovsky Cc: Marek Szyprowski , Christoph Hellwig , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Robin Murphy , Joerg Roedel , Will Deacon , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Masami Hiramatsu , Mathieu Desnoyers , =?iso-8859-1?B?Suly9G1l?= Glisse , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, iommu@lists.linux.dev, virtualization@lists.linux.dev, kasan-dev@googlegroups.com, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, Jason Gunthorpe Subject: Re: [PATCH 0/8] dma-mapping: migrate to physical address-based API Message-ID: <20250630133839.GA26981@lst.de> References: <35df6f2a-0010-41fe-b490-f52693fe4778@samsung.com> <20250627170213.GL17401@unreal> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250627170213.GL17401@unreal> User-Agent: Mutt/1.5.17 (2007-11-01) On Fri, Jun 27, 2025 at 08:02:13PM +0300, Leon Romanovsky wrote: > > Thanks for this rework! I assume that the next step is to add map_phys > > callback also to the dma_map_ops and teach various dma-mapping providers > > to use it to avoid more phys-to-page-to-phys conversions. > > Probably Christoph will say yes, however I personally don't see any > benefit in this. Maybe I wrong here, but all existing .map_page() > implementation platforms don't support p2p anyway. They won't benefit > from this such conversion. I think that conversion should eventually happen, and rather sooner than later.