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 62092CA5FA5 for ; Tue, 29 Sep 2026 11:22:02 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4hvG3X55jvz2yvy; Tue, 29 Sep 2026 21:22:00 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=172.234.252.31 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790680920; cv=none; b=mJCPDFhEseRZ9jBYk/Yw11rn5ylJ4C5o0WD5z0jjTCx+mBVUkxhiRk8Tz9fYr+PZ6Hg6c9MPEwiZ6860OSzkTc/NEFVKnq1oZI2FM+jPXwmaZm4Dvp6peFsYOLgLcI6+1HfFZus955mDeVqyEY2e/+Bio1YKwiuaNksaKP64Ert3M5iLxOKb5Tg8S2kYQZn8M/K57ygRgoJAtWHJbz5+4Uvh3RAqwRUTQscOaUaJdhoZIH8SStXUmP05FaN1hHIp6OBc9jN2sCzIPr9Oj1FR5G8cmOeb2M6JyFpo21R68GfHMQPegzB4SDnjKb4fOI5ew0sPcVfKX2HtDsnUevKOpw== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790680920; c=relaxed/relaxed; bh=2fPL1r0q3ZFaPVm8LMil7KkezedSBA8/3rMeLvpxPeA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=N/0lag5ciRVVn3hIzJz8WoxLSYP/0gSunoZJgCrm9W4hs1DM2nz/S5hKr7EDhcf7PeK80I8OORkzvWh2BOiWhZpdrrA3JcaRw5K6X0HV/VAWb9b+sJCUhsmFE+kjwOouzdH+7DxXS0ZCmrPHWOTpQcX96PNdAlZyj+PT0yJ+41sMws37HlsRaDKs7KPjjoUeKsnwicveo6UlCGeU9NzB7cQPrsUDiV1OsOR4Fb1HJWf8fD5MkxZ1e6H3LlpwTXniNW2Zfm897FU6RtPSrtLCmaMM2tk98g4i84bVI2liWBzEVKxh4B1Gj03AUciG7S57tOdITMXPzpF7Evq6yxt9bA== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=R7ZIalgU; dkim-atps=neutral; spf=pass (client-ip=172.234.252.31; helo=sea.source.kernel.org; envelope-from=ljs@kernel.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=R7ZIalgU; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=172.234.252.31; helo=sea.source.kernel.org; envelope-from=ljs@kernel.org; receiver=lists.ozlabs.org) Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4hvG3W4ZhGz2yft for ; Tue, 29 Sep 2026 21:21:59 +1000 (AEST) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id DC5D640D70; Tue, 29 Sep 2026 11:21:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3D1B1F000FF; Tue, 29 Sep 2026 11:21:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790680917; bh=2fPL1r0q3ZFaPVm8LMil7KkezedSBA8/3rMeLvpxPeA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=R7ZIalgU2YxoignykHVl41GbwXVq+ymjE2Si4HRcFErNll2DzNwd43/xyUICNL9Gh ZKbhOo6icKbcmsuOqmHY4vcYGDVk0I9HhEjHuNVoiCF/g/yVcf+z3KLnyerzZ1MiXd W5Z9bZBV7t1tkUZVxlpq6Ci9stfsy0TAMMeCuz+nSAiebkXEgWtguADRz3DWyBpZ+H mIWJYnCrwO2dvpBgpuGcPLGHOAHxCMNlWV4hSF1En76lTAsSQsZ+wBOPbyH1ksC26r xgTJ+Vceyq3XFJSuuzXLjQ/8jCstGixi8blBDf2nxCsI5axooCKVBfsc28vfxzNygJ YWOKPhtuzPNAg== Date: Tue, 29 Sep 2026 12:21:22 +0100 From: "Lorenzo Stoakes (ARM)" To: Zi Yan Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , David Hildenbrand , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Greg Kroah-Hartman , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Paul Moore , Stephen Smalley , Jaroslav Kysela , Takashi Iwai , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Doug Gilbert , "James E.J. Bottomley" , "Martin K. Petersen" , Jaya Kumar , Simona Vetter , Helge Deller , Sebastian Reichel , John Hubbard , Peter Xu , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Rik van Riel , Harry Yoo , Juri Lelli , Vincent Guittot , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Arnd Bergmann , Muchun Song , Oscar Salvador , "Matthew Wilcox (Oracle)" , Jan Kara , Marc Zyngier , Oliver Upton , Catalin Marinas , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , "David S. Miller" , Andreas Larsson , Alexander Viro , Christian Brauner , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-rdma@vger.kernel.org, selinux@vger.kernel.org, linux-sound@vger.kernel.org, bpf@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, fuse-devel@lists.linux.dev Subject: Re: [PATCH v3 09/40] docs: filesystems: update mmap_prepare docs for discontig kernel pgs Message-ID: References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-9-4583d8a23bca@kernel.org> 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: On Fri, Sep 25, 2026 at 05:01:51PM -0400, Zi Yan wrote: > On Thu Sep 17, 2026 at 12:22 PM EDT, Lorenzo Stoakes (ARM) wrote: > > Documentation/filesystems/mmap_prepare.rst | 81 ++++++++++++++++++++++++++++++ > > +* ``discontig_kernel_map_page()`` - Maps a single page, correctly handling > > + compound pages (if the compound page is bigger than the remaining pages in the > > + VMA, then only those pages that fit will be mapped). For a compound page, the > > + head page must be passed. > > +* ``discontig_kernel_map_page_range()`` - Map an array of pages of a specified > > + size. Note that if the number of pages specified exceeds the VMA size then an > > + error will arise. > > Why do mapping a compound page and a page range have different behaviors > on the bound? Either both do partial mappings or give errors when a > given input cannot be mapped as a whole in the VMA. Ack, yeah similar to Suren's point on patch 8, will clamp for both. -- Cheers, Lorenzo