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 C73C3C0015E for ; Fri, 28 Jul 2023 16:58:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 124778D0001; Fri, 28 Jul 2023 12:58:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0D5136B0074; Fri, 28 Jul 2023 12:58:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EDE778D0001; Fri, 28 Jul 2023 12:58:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id E0F4A6B0071 for ; Fri, 28 Jul 2023 12:58:38 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id A54278067C for ; Fri, 28 Jul 2023 16:58:38 +0000 (UTC) X-FDA: 81061629516.19.ACB53AC Received: from mail-yb1-f172.google.com (mail-yb1-f172.google.com [209.85.219.172]) by imf21.hostedemail.com (Postfix) with ESMTP id D138B1C0004 for ; Fri, 28 Jul 2023 16:58:36 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20221208 header.b=Ucc+Ivgz; spf=pass (imf21.hostedemail.com: domain of hughd@google.com designates 209.85.219.172 as permitted sender) smtp.mailfrom=hughd@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1690563516; a=rsa-sha256; cv=none; b=8ByroaXRbEPqmAIO/R6QBMPxRu1RCnJ/WUwntGQSFyAgSvGnYzYddRszc29rtBXuIyM38z 9Qv0AXOoXYb/JoXFhs+tr7zxKbBSoTKSQC5kBevyd+IKnBYwpGcXLYfP9tvcXIMrf6PspI fvxkadKlei9EgsQelugu0WuKYzOhyEA= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20221208 header.b=Ucc+Ivgz; spf=pass (imf21.hostedemail.com: domain of hughd@google.com designates 209.85.219.172 as permitted sender) smtp.mailfrom=hughd@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1690563516; 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=GShiyClog5JSkUZzXvC/x80xpfvHryo9mYUqQG38Cyg=; b=EHCyDz0hv/raKQ9/dnDi52x5KSLMSbmG5cvKYPSZyeDrEXVpdgkK4FqaGD9DUO0EUWaSiz i9/cnnSN5nHQy/dG9NBopJ/j4dUaTbS5bCFznSuyvQd2YRfujDuKfZppD4kV/3L2Akkexc zlpQ+ZG/6P8DoJ3SBVrbtXYwgVoj6ao= Received: by mail-yb1-f172.google.com with SMTP id 3f1490d57ef6-d13e0bfbbcfso3270736276.0 for ; Fri, 28 Jul 2023 09:58:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690563516; x=1691168316; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=GShiyClog5JSkUZzXvC/x80xpfvHryo9mYUqQG38Cyg=; b=Ucc+IvgzgYZ0O9vdpuyWtxAY2hyIte0l1ud1lTHNqf3oz+BHJOulr13wgd/5mqLYWE wsmBBCQ4ISMtw6+WgTwGz5ov1T81nFuUlYYzVU62nm7J3vwvq6bCQeHf6AsIIk10GxEG oPdx5sRvSt/k6mhtJgP1YhjZC6qoQRfRPKbvnpKqm4gMIChhgpCEmeWc0w0SCR47ENYN +En4cvk+uyC35wOQWNDyT9flOQHvJfa8+/Vz729j6L4BmClQFiHKFazBQEubog0Xb34u 6QK5K6cSEgMtvFwurFRdKYFASlK6rYxs+QOnkG7+Syfdvu2K/uFVPtL4rOv0L9tmd0Js Zb9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690563516; x=1691168316; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=GShiyClog5JSkUZzXvC/x80xpfvHryo9mYUqQG38Cyg=; b=CjOqYRlYjY3HRWh0qsUKYJJZpp908GExoxYjfE5LQDURUI5/yLOnNbR/NWw80N+g9W pLGgYvopIRaZkt2lKBMjUKg5T27KFB6g1lH6czymswibjjqvOVpmK27F1XwWYMyy1dMD MtQDdXqu6WRlz9JGOzduFXcG+cPhuAXmYCo4AlDqxD4JwNOiw3pRo4epHqFy78q3OHxD 3Kr99EG17O6eJX/G3om6ivkkeMRK3vUaALu63ObUQv3H5aLOmO2yZblcD83AsPAXMoI3 7rn8Aibw9/Wb3hSwC9ePVgCdqH3zu5vxpV3JGkYk4LxrKgkF0zqNMegtdXU9yCkjkrNj DM8Q== X-Gm-Message-State: ABy/qLYZbdt+ydHmJoqbbv1qMOiAefj8vbj9JJSVqb1lEPLzVf5DRJ2i YLS+1XipKP8ez3G7UeJ2IzvK2A== X-Google-Smtp-Source: APBJJlHBFbMizlgcqeLaat734RR0N6/qgmeCbKXzz/m5ekuONhKnRvLKwdVWxRCif5G55jvVMt82Ag== X-Received: by 2002:a25:a362:0:b0:d07:2183:f547 with SMTP id d89-20020a25a362000000b00d072183f547mr2206323ybi.32.1690563515748; Fri, 28 Jul 2023 09:58:35 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id y200-20020a25dcd1000000b00d1e6e93e8f5sm913403ybe.51.2023.07.28.09.58.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Jul 2023 09:58:35 -0700 (PDT) Date: Fri, 28 Jul 2023 09:58:22 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Yongqin Liu cc: Matthew Wilcox , Hugh Dickins , Andrew Morton , Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Lorenzo Stoakes , Huang Ying , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , Ryan Roberts , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 04/32] mm/pgtable: allow pte_offset_map[_lock]() to fail In-Reply-To: Message-ID: References: <2929bfd-9893-a374-e463-4c3127ff9b9d@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D138B1C0004 X-Stat-Signature: a7bmaead6pcyjumwdzj8ckzmrydbwpy5 X-Rspam-User: X-HE-Tag: 1690563516-815995 X-HE-Meta: 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 DgH6n+Im F7y1wA0eT8CCDnw52N5EXm/O5nDCG4WQV/0urqb2PhG5mJApdJcRpbbxOx27zdoTpZ5iqeQGxmhriQx3J8u/bdvl8HHhw5+TWetK9+A0oH0qnv4pOK6XostquIcOUbCIK9k+LrLi4W88+8VeFwXaowtLI85HbfJEe1Gr2BeqVcLP4gzY7xu2AwZsPddWX6TMpt9ycNdCGocoF0LWB1x8csz1Idizl2rdEdS/n9c/SlwIDssrksYfOoijQUoumHNyn019zMSTLYUmA6fOsLGaM8pSv68yXRow2YL3zHZg8YQ22+tkmECzr+N+XjX4bxKVd5HCgSO21UmyqW24MDtJsArftNuhOYCUkkvQGSfcsKZ65HKOPz2yzeHK77aRzASS45yKacA10M2bq0Q+MedXEIOHdRu+wggUvsrNt 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: On Fri, 28 Jul 2023, Matthew Wilcox wrote: > On Fri, Jul 28, 2023 at 09:53:29PM +0800, Yongqin Liu wrote: > > Hi, Hugh > > > > It seems this change makes pte_offset_map_lock not possible to be > > called in out of tree modules, > > otherwise it will report error like this: > > ERROR: modpost: "__pte_offset_map_lock" > > [../omap-modules/android-mainline/pvr/pvrsrvkm.ko] undefined! > > > > Not sure if you have any idea about it, and any suggestions on how to > > resolve it? > > Please explain why this module needs to map page tables +1 Thank you for testing 6.5-rc, and I am sorry to have inconvenienced you. But there is not one example of an in-tree module needing that, which is a very strong hint that no module should be needing that. Sounds like pvrsrvkm.ko wants to muck around with page table entries, without the core mm knowing. Not something core mm can encourage! If what pvrsrvkm.ko is aiming to do there would be useful for others, maybe its owner can share that, and work with core mm developers to expose a generally useful interface - but that is not likely to be __pte_offset_map_lock itself. Hugh