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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53016C83029 for ; Mon, 30 Jun 2025 13:38:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7FE068D0002; Mon, 30 Jun 2025 09:38:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B4218D0001; Mon, 30 Jun 2025 09:38:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6EBC98D0002; Mon, 30 Jun 2025 09:38:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 5D9FF8D0001 for ; Mon, 30 Jun 2025 09:38:51 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 0DC6F59679 for ; Mon, 30 Jun 2025 13:38:51 +0000 (UTC) X-FDA: 83612172462.18.77941E4 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf09.hostedemail.com (Postfix) with ESMTP id B5EF614000E for ; Mon, 30 Jun 2025 13:38:47 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=lst.de; spf=pass (imf09.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1751290728; 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; bh=9EB5M+oZCNFUrXucC6vFVumKTSV4tlIG2ltmQJJW9N4=; b=VIFCJ431WQunZnDCE0g23DP7xfPkazBmzcN63ruZbFDK7K/RpCNfY24d7vDT4rJo9N1tuI nxN3+Ln0Fx15MWwZHw8twBgRXjCASRJ39eOoksUGHLiSlmq27lwjmUZ983FSyG+N4X2lgD 8tVxqHuTkSuSZfcJzcGahE8iEEtZ8EQ= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1751290728; a=rsa-sha256; cv=none; b=Wa66F/7Q0EcYXgsFiTdTzgEdsd+9XRpMgchppyV2bQsGltsrvID21LyO/yP1BpYZz+ewpr jGLDbtwEBJE52u7za7so+P7oLnbX/vGcS0L7x2HG5TpkQGxpXIUNE4JEgwlhAJVmBT9WSe T5NYLGCXqhe2qpMf8cV5VtR9ZBjTrjg= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=lst.de; spf=pass (imf09.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de 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> 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) X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B5EF614000E X-Stat-Signature: eookipwk5bfz85r37fnbd47nsgcea8g9 X-HE-Tag: 1751290727-671364 X-HE-Meta: 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 c5ZnwzAM uc3rSqu5tCXHVU4m8VsvjlbngjSoOwqP/SJXyXwCFUqhxfvshb/AVum9nD+rXHzwlMgpXQ/+2kz9peRw1Zc775dXNr+djM9JtPprNIJoZPpw90JHHA1956K7iQA== 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 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.