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 69766C79F82 for ; Tue, 8 Sep 2026 16:13:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 348F26B009E; Tue, 8 Sep 2026 12:13:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 320776B00A1; Tue, 8 Sep 2026 12:13:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 211866B00A5; Tue, 8 Sep 2026 12:13:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id D38536B009E for ; Tue, 8 Sep 2026 12:13:53 -0400 (EDT) Received: from smtpin21.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 60BDCA4DB4 for ; Tue, 8 Sep 2026 16:13:53 +0000 (UTC) X-FDA: 85191091146.21.FD90AB9 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf01.hostedemail.com (Postfix) with ESMTP id 7C3344000C for ; Tue, 8 Sep 2026 16:13:51 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="QZQ0bmB/"; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@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=1788884031; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=tOS0VQ3pxNli+fnzbQ+4GcgPT7gVlj6GtERNyCqVDto=; b=j+z591pqsjlMqyEmG7giKuZowdAGwLEc28pQN/250v25dPCy2YqgVZclmx+7XBndG6Xgnc 28gdoUdmc1IEuy9dgv5OxJOp0+R4CXF5v05+n0YqGGLOtetqGEPRiPHc11cAUyz9EigbjE tUniOLvaaM8XLKeIV9WXsBgpG3r8DPk= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788884031; b=R+1YkyLrpbPtx7P7hm+vnrDMstfeFFPkmsk6IX2HyueVueeZOqE5iN7hrpXy+P5b/xcdvY 91JQCFG1uwOtsoXfZ1QJUl/87D176uOrxT5y4uVMd9yBbPKqoyzEjjvUA6Z+Jje/c+BY8k kSVGaFshrzuV0uUH0EiQe14BW3cKoQU= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="QZQ0bmB/"; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 9FA5743AF2; Tue, 8 Sep 2026 16:13:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5817D1F00A3A; Tue, 8 Sep 2026 16:13:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788884030; bh=tOS0VQ3pxNli+fnzbQ+4GcgPT7gVlj6GtERNyCqVDto=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=QZQ0bmB/xT1mMR2EivpC8SAALYplDz/p6XJ0LwSWEjUfwX5385zpmTa2JuhsIXPUz YBo5HdXD6sRD/GHk3xVJ1OQ/eE/sNDGIVV8sio1XqhsRZsX480hZzYkuJOQVuocYGI uLBbckItcXqaxCFSwIWMkFwhlz6IsIrVSvCQrrcqv76HGZTUW6BnqRnGFYhU59fOsR 9+rUnPQ0nQHjFIcBv8E9aRovC8q+V57ExoA9EwmSpcdtj2Di9ZDREn5tjZVYkkgnED Z3yu3BRW65/MCTVMPWLWLlj8Tg5zXSc8IxoD/XhjBruToNa2OlwWOY/ySqhe6mHulf rD8JuF/Z6xQbg== Message-ID: <5b02f5de-00b6-4f8e-9e30-6d0acedafaf4@kernel.org> Date: Tue, 8 Sep 2026 18:13:37 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 08/14] erofs: use folio_attach/detach_private() instead of direct assignment To: Zi Yan , "Matthew Wilcox (Oracle)" , Andrew Morton , Muchun Song , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Gregory Price , Ying Huang , Alistair Popple , Johannes Weiner , Qi Zheng , Shakeel Butt , Kairui Song Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Gao Xiang , Chao Yu , Yue Hu , Jeffle Xu , Sandeep Dhavale , Hongbo Li , Chunhai Guo , linux-erofs@lists.ozlabs.org References: <20260907-remove-pg_private-v3-0-6ae22f9d9272@nvidia.com> <20260907-remove-pg_private-v3-8-6ae22f9d9272@nvidia.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260907-remove-pg_private-v3-8-6ae22f9d9272@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 8duir44ihx7kx8dnyqog93kbpp6w6dd8 X-Rspam-User: X-Rspamd-Queue-Id: 7C3344000C X-Rspamd-Server: rspam03 X-HE-Tag: 1788884031-39667 X-HE-Meta: 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 /lIQb7I3 vJqTgovzmelc6PoYQ6xViVng8D8TytPUgG+lmCVFfIcbsw4qHwMqty4F3jU8mDGtRkSr++OJ8SrqkXxV3B4NUDeLa6uMp5h9sL+MKXUAcSM3CfoE02nSHobO5zXdPrJYJr9vuF6BZMBrdHtsu7h59Uo8S4Ys60YtVTOrWsNiOyLTlKTYU/juUSaCfFzgGmdKOJ33praG/7iwDIjlN+jhDLJ8iX0eFNio5HCLrV3kfeD9ZlqC0O3fcSIt026Z88fMwVt2z+xmdyLB6twH9udf17VABRAPaeUXcyuOLV1YETduWjrMLpjPTzwdCpNzQTtnLJBpgYQlZBfWK+/Y= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/8/26 04:56, Zi Yan wrote: > erofs_onlinefolio_init/split/end() use folio->private without setting > PG_private or increasing folio refcount and it works. But after PG_private > is replaced by checking folio->private in a future commit, it can break > folio_expected_ref_count(), since the folio has private data without > elevated refcount. Change them to use folio_attach/detach_private(). Freezing the folio will properly work I assume, as we'd always freeze with that refcount in mind or remove the reference (detach private) early? I'm thinking of folio_ref_freeze() in __folio_freeze_and_split_unmapped(). Or is the ref only very short-lived either way such that we don't care? -- Cheers, David