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 54E3ACA5FE3 for ; Fri, 2 Oct 2026 12:12:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6381A6B0088; Fri, 2 Oct 2026 08:12:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5E91E6B0095; Fri, 2 Oct 2026 08:12:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4C98C6B0096; Fri, 2 Oct 2026 08:12:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 2807F6B0088 for ; Fri, 2 Oct 2026 08:12:46 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id A84651A06F8 for ; Fri, 2 Oct 2026 12:12:45 +0000 (UTC) X-FDA: 85277574690.19.7FD7144 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf05.hostedemail.com (Postfix) with ESMTP id 2343A100009 for ; Fri, 2 Oct 2026 12:12:44 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=c4yl8biB; spf=pass (imf05.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@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=1790943164; 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=nX94dzJL8Kj3ESX88e5wjImNlNtcKNqoM+7SGcE8uW0=; b=4sZSopnLi0DNOs3bytIq2C8N0rDfAC0DmgR81/6RUpJd/SmW9AMc+z9f8FzjhqhBmVIfdV N/o4ikPhZ8e1DTS7cbyJ91RWoqvQtvXqUK1iYSeXS7ONvh51fC/irqnI5HQim6V1h5NTQN AksjwqstJA729cW0b+QYLKdTbs6mA8g= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=c4yl8biB; spf=pass (imf05.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790943164; b=Egz9Y3lvPCoc39xo3Wqdhv+4T5dfr79eiclSvFQ1OCj7WG32OHORAaHlsEH6Vz8CtzBR6V o2bT8sTLyyuV6w1g4K+VeNeM5d9Xq4f4/9fcFSA0fZ1wveEqjNe/0kldvWHtwqKXXBS+y/ FpG+wTHiIINwYdtL+D3t1FIHe1f5JCU= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 0E40A60A8E; Fri, 2 Oct 2026 12:12:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B7891F000FF; Fri, 2 Oct 2026 12:12:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790943162; bh=nX94dzJL8Kj3ESX88e5wjImNlNtcKNqoM+7SGcE8uW0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=c4yl8biBSZCOSz8O02PAfeH7eOGxEphl+j5zx68yHK0rGgywavDJhETeCqFXtb525 drYTuH322sqP8NPQ5ZewzHTnVOIMhBthJu+BRfYK/9P82Fewt1qESLmLaBje/QXlbU DwFWnhrzPDhC7iHk2BYxuuux04WkpQ1QaA4z1giCRe1/CYf+j/udPDx9BpMRBgE+zE 0Pp4Nr8nepmdcGz6T4V/ZJP/q0Yksmr01oznoU9EHFYDe+Pybk4DVG6cBSpehyP9Up XaZfWzb0H55uTLR1CMcTUrzHQC2okp7EhDFf3/godjZFN6JSYYuusCC9eACzBjmltf QSU/lT7DTm+dw== Date: Fri, 2 Oct 2026 13:12:20 +0100 From: "Lorenzo Stoakes (ARM)" To: Lance Yang Cc: linux-mm@kvack.org, "Liam R. Howlett" , Andrew Morton , Jann Horn , Pedro Falcato , David Hildenbrand , Suren Baghdasaryan , Mike Rapoport , Vlastimil Babka , Michal Hocko , Jonathan Corbet , Paul Moore , Leon Romanovsky , Greg Kroah-Hartman , Dennis Dalessandro , Jaroslav Kysela , Jason Gunthorpe , Thomas Gleixner , Usama Arif , Dave Hansen , linux-kernel@vger.kernel.org, Kumar Kartikeya Dwivedi , Daniel Borkmann , Eduard Zingerman , Zi Yan , Nico Pache , Namhyung Kim , Ryan Roberts , x86@kernel.org, Dev Jain , Barry Song , Kiryl Shutsemau , "Martin K. Petersen" , Baolin Wang , "James E.J. Bottomley" , Simona Vetter , Peter Xu , Masami Hiramatsu , Sebastian Reichel , Borislav Petkov , Arnaldo Carvalho de Melo , Harry Yoo , Rik van Riel , Peter Zijlstra , Helge Deller , Mark Rutland , Ingo Molnar , Juri Lelli , Maarten Lankhorst , Vincent Guittot , Thomas Zimmermann , Catalin Marinas , Nhat Pham , Gerald Schaefer , Maxime Ripard , Nick Piggin , "Aneesh Kumar K.V" , Muchun Song , Marc Zyngier , Will Deacon , "Matthew Wilcox (Oracle)" , Arnd Bergmann , Madhavan Srinivasan , "David S. Miller" , Paul Walmsley , Anup Patel , Palmer Dabbelt , Albert Ou , Vasily Gorbik , Baoquan He , Andreas Larsson , Claudio Imbrenda , Kemeng Shi , Gregory Price , Rakie Kim , Christian Brauner , Alistair Popple , Axel Rasmussen , linux-doc@vger.kernel.org, Alexander Viro , Matthew Brost , Ying Huang , Byungchul Park , Joshua Hahn , Xu Xin , Chris Li , linux-usb@vger.kernel.org, Qi Zheng , Yuanchu Xie , linux-rdma@vger.kernel.org, selinux@vger.kernel.org, Youngjun Park , Chengming Zhou , Wei Xu , Miklos Szeredi , linux-sound@vger.kernel.org Subject: Re: [PATCH v3 10/40] drivers/usb/mon: update to use mmap_prepare + map kernel pages Message-ID: References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-10-4583d8a23bca@kernel.org> <90811f7b-1751-49cb-bf0b-3d5ee7f10e45@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <90811f7b-1751-49cb-bf0b-3d5ee7f10e45@linux.dev> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 2343A100009 X-Stat-Signature: rojah6hhxwh54nq1i9bat9w66bfzpd79 X-Rspam-User: X-HE-Tag: 1790943163-263256 X-HE-Meta: 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 4aUKjPEp wEC+00HFwj6zBLUwmtFocyMuo8SnHtAzoHEKC/GE792V0gW+4+qPmelrLPbxinfhx4VJ47mQpK+tqCrKntEBcrfsjqa9pEkBevhuh7WpT5DSZza5lEWr2hszV5PcAJpzQ4rq1yauG1Cc2NeKb1jImT6kPdK8P0o+pQgAdDOAZ77vW2yjHuAM0d31Phjla8Nky38mjZ+yKoK8k57vwwKjfZZxWUGDgSj0HUUMwdE7UNXBd7Srs7wVTVPDBq3T4aBltRtZY8vVgDIF3llx1FVzXU7YoVd80FaXbAaaib2PziPfqexs9zbck9AuYywmK9PK3N7avFCWDPVxDwMHZVJ3Y0eQix4cqPM2dJb1nsfL3ZUaDpuFrUOH8IcUv/Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Oct 02, 2026 at 05:55:56PM +0800, Lance Yang wrote: > > > On 2026/9/18 00:22, Lorenzo Stoakes (ARM) wrote: > [...] > > +static int mon_bin_discontig_init(void *vm_private_data, void **private) > > +{ > > + struct mon_reader_bin *rp = vm_private_data; > > + > > + /* Dropped by mon_bin_vma_close() on unmap, including on error. */ > > + __mon_bin_vma_open(rp); > > Em ... If Coda uses a usbmon container and the first page insertion fails > (e.g. -ENOMEM when allocating a page table) after mon_bin_discontig_init(), > where is mmap_active decremented? > > mmap_action_finish() returns the error when is_compat is true, and > mmap_file() then replaces vm_ops with dummy ops. > > Am i missing something? No, indeed, the contract isn't honoured in the compat path. It can't actually happen in practice - the compat layer is only ever accessed from a stacked filesystem and those only stack on regular files. But I should probably update this to be strictly correct regardless to be consistent with the non-compat path. Let me see if that looks sensible and rejig for v4, thanks! :) > > > + return 0; > > +} > > Cheers, Lance > > [...] -- Cheers, Lorenzo