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 C26DCE77184 for ; Tue, 17 Dec 2024 00:47:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EABA26B00A3; Mon, 16 Dec 2024 19:47:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DC1866B00AD; Mon, 16 Dec 2024 19:47:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BC7396B00A3; Mon, 16 Dec 2024 19:47:48 -0500 (EST) 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 99D326B00A5 for ; Mon, 16 Dec 2024 19:47:48 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 2F60A1A0194 for ; 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d=hostedemail.com; t=1734396446; a=rsa-sha256; cv=none; b=Mh8B+gOdo5OkF29m/Zg1odQEKEqIsALT6MEG6PuhQIRmIMpAmC/v78vq3qiWH/+CoPk/tr unSspzf2RrI7jiuibEVbAJcFiydM9OL/NKmA5qCyyenjxpB6PVJ+gwNxe8XnRvScx5yUtk bRgNzwvKU0jo3QFLD6DagNrcwbs1Z+I= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=none; spf=pass (imf12.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de; dmarc=none Received: by verein.lst.de (Postfix, from userid 2407) id 594C268D1E; Thu, 12 Dec 2024 09:48:57 +0100 (CET) Date: Thu, 12 Dec 2024 09:48:56 +0100 From: Christoph Hellwig To: Leon Romanovsky Cc: Jens Axboe , Jason Gunthorpe , Robin Murphy , Joerg Roedel , Will Deacon , Christoph Hellwig , Sagi Grimberg , Leon Romanovsky , Keith Busch , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , Marek Szyprowski , =?iso-8859-1?B?Suly9G1l?= Glisse , Andrew Morton , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Randy Dunlap Subject: Re: [PATCH v4 11/18] mm/hmm: let users to tag specific PFN with DMA mapped bit Message-ID: <20241212084856.GE9376@lst.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3DFAE4000D X-Stat-Signature: j4w1a7qgde3bq7wrjzgmrwqtgeib4syr X-Rspam-User: X-HE-Tag: 1734396452-256657 X-HE-Meta: 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 zxkmGblI MKdsZoOCs/RlC7v/6+y0HpG0C14wixriMBtF/82uZ1mmSa+PDQvq5Grh+ZSXQMnmytBXLsi/bN3TMl8x2zsulhYw/Vkq0LdNb0cToIiqP47dht80F/eEuqRynlfc438vgTLbBTDNL1yb8eNDxI71vqJDEV8EZ65WDsllkdG3tr18eG+s+xvXfDqjA7IozTYGSu63ZAOl8RcRCljBiDCpHdDHMb8Aopj1MIwyH 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, Dec 05, 2024 at 03:21:10PM +0200, Leon Romanovsky wrote: > From: Leon Romanovsky > > Introduce new sticky flag (HMM_PFN_DMA_MAPPED), which isn't overwritten > by HMM range fault. Such flag allows users to tag specific PFNs with information > if this specific PFN was already DMA mapped. Missing line wrap at 73 characters here. > > @@ -253,14 +262,14 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, > cpu_flags = HMM_PFN_VALID; > if (is_writable_device_private_entry(entry)) > cpu_flags |= HMM_PFN_WRITE; > - *hmm_pfn = swp_offset_pfn(entry) | cpu_flags; > + *hmm_pfn = (*hmm_pfn & HMM_PFN_INOUT_FLAGS) | swp_offset_pfn(entry) | cpu_flags; Please avoid the overly long line here. That being said I hate the structure here. Can't we just have a local variable for the actual new pfn value, and then a single goto label at the end that takes the keeper flags from the argument and assigning the new out value to *hmm_pfn instead of duplicating this in half a dozen places?