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 A60DAF47CB7 for ; Thu, 5 Mar 2026 19:07:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1AC536B0089; Thu, 5 Mar 2026 14:07:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0936A6B008A; Thu, 5 Mar 2026 14:07:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E30EE6B008C; Thu, 5 Mar 2026 14:07:56 -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 CD0B36B0089 for ; Thu, 5 Mar 2026 14:07:56 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 8C926160232 for ; Thu, 5 Mar 2026 19:07:56 +0000 (UTC) X-FDA: 84512944152.24.FC18A5B Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf09.hostedemail.com (Postfix) with ESMTP id A43A7140018 for ; Thu, 5 Mar 2026 19:07:53 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Dj+S9NqJ; spf=pass (imf09.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=1772737673; 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=TPptAqQRbsvtF5CPju5gas6bGn5iTFeGYsXCc/CnCs4=; b=gtwifuvu6Hjauxql+5Ho8YEYAOO8u0VpkhTuJ4AgiQVyXkqQC+Q+SHfPNuK4jJb3K1ae+8 87isYHlp1oKWwFKp2nKmk9XkCMqmbHsz8aRDQJRE5maQbG/3Dt3GSNKzmtw/CDqmmRqCt4 +fnMu4+wplOQl+XYS0uUftWxTbcp6RQ= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Dj+S9NqJ; spf=pass (imf09.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772737673; a=rsa-sha256; cv=none; b=FLP/xKKTVZFngb3CsalTfwSfZeT/kZjSTpzEqCwDq2LENQ/VQY+Sx+zE/JL+Q7yEElLsy1 PUPtwXc7yPF+4mHsMSGb5MumoOCtoz7/ucNycgimZXJqRnJXKqfQpuKjLtFdBr3exUlNwK U9KhOhalMiwCB7Dhe2aFPsG3it4U4gU= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 5D78D40713; Thu, 5 Mar 2026 19:07:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DEB6C116C6; Thu, 5 Mar 2026 19:07:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772737672; bh=5pMLMYsqUq30caMaqSsCRxg/LUKm2ZwH02Nogw/kZgk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Dj+S9NqJtdWz6RBKFzR5acMgUZFQJ3W9fnbktBvz0MaAXoouPnMmfQ67JZmI9sVaH XQQn6nGUQIhWbu93psky7lo+eqRxXjl34agykwtcFCvJvewXz2H9sBqggtK338M1DH xMqK0z98I7O58rU2ZExHxgDfn0muFBjv+va4ZBeTvQF1Iwu5bpIwVn7xVrLxpkhupp DOdrZ4sFZpJOpYA2rNekO31hBtA1G0t1/f5tBT933AusAvejWixb3X2YXLYp78nijl 5WoPlj74YRUASEEXS5XuY65yzkQQnpYLuAnUfI3m9ww+joTZUYCqAu4oOizyBIoyL/ rUJ6jp5aQodrA== Message-ID: Date: Thu, 5 Mar 2026 20:07:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 04/15] mm/gup: drop local variable in gup_fast_folio_allowed To: "Kalyazin, Nikita" , "kvm@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "kernel@xen0n.name" , "linux-riscv@lists.infradead.org" , "linux-s390@vger.kernel.org" , "loongarch@lists.linux.dev" Cc: "pbonzini@redhat.com" , "corbet@lwn.net" , "maz@kernel.org" , "oupton@kernel.org" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "seanjc@google.com" , "tglx@kernel.org" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "luto@kernel.org" , "peterz@infradead.org" , "willy@infradead.org" , "akpm@linux-foundation.org" , "lorenzo.stoakes@oracle.com" , "vbabka@suse.cz" , "rppt@kernel.org" , "surenb@google.com" , "mhocko@suse.com" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "martin.lau@linux.dev" , "eddyz87@gmail.com" , "song@kernel.org" , "yonghong.song@linux.dev" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" , "sdf@fomichev.me" , "haoluo@google.com" , "jolsa@kernel.org" , "jgg@ziepe.ca" , "jhubbard@nvidia.com" , "peterx@redhat.com" , "jannh@google.com" , "pfalcato@suse.de" , "shuah@kernel.org" , "riel@surriel.com" , "ryan.roberts@arm.com" , "jgross@suse.com" , "yu-cheng.yu@intel.com" , "kas@kernel.org" , "coxu@redhat.com" , "kevin.brodsky@arm.com" , "ackerleytng@google.com" , "maobibo@loongson.cn" , "prsampat@amd.com" , "mlevitsk@redhat.com" , "jmattson@google.com" , "jthoughton@google.com" , "agordeev@linux.ibm.com" , "alex@ghiti.fr" , "aou@eecs.berkeley.edu" , "borntraeger@linux.ibm.com" , "chenhuacai@kernel.org" , "dev.jain@arm.com" , "gor@linux.ibm.com" , "hca@linux.ibm.com" , "palmer@dabbelt.com" , "pjw@kernel.org" , "shijie@os.amperecomputing.com" , "svens@linux.ibm.com" , "thuth@redhat.com" , "wyihan@google.com" , "yang@os.amperecomputing.com" , "Jonathan.Cameron@huawei.com" , "Liam.Howlett@oracle.com" , "urezki@gmail.com" , "zhengqi.arch@bytedance.com" , "gerald.schaefer@linux.ibm.com" , "jiayuan.chen@shopee.com" , "lenb@kernel.org" , "osalvador@suse.de" , "pavel@kernel.org" , "rafael@kernel.org" , "vannapurve@google.com" , "jackmanb@google.com" , "aneesh.kumar@kernel.org" , "patrick.roy@linux.dev" , "Thomson, Jack" , "Itazuri, Takahiro" , "Manwaring, Derek" , "Cali, Marco" References: <20260126164445.11867-1-kalyazin@amazon.com> <20260126164445.11867-5-kalyazin@amazon.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: <20260126164445.11867-5-kalyazin@amazon.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: A43A7140018 X-Rspamd-Server: rspam07 X-Stat-Signature: pywo4t7bc7z3jr3dna9fykffoesey814 X-Rspam-User: X-HE-Tag: 1772737673-308560 X-HE-Meta: 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 xD4/qGRm XlfCFMHPknd84yuXQuXg2fSDB+DO+yTW2v9EaC/tDKH95e9Ey5CmpMDCX4mMSj380xmJT1ucP3Jwd2YQsw97hOPLbGCMu4qvFHOuVSaiNovYK+XIaw1KLub+QWJDUJtIxM3IYQLR34QfYFgSrHUHiFF5jyMUV/xJ+b336FDPY4WUVU/3y0jM9+ZBbVSIR8xz80UMG6lZDQnLj5g2kH23DVlR8C4Wv+iTBRi0VA7mXFaokv1enOy5I+NqkKNoX7dsQq21j0otxBmdq989UqorSZbWPqixoj6VM+cV0YmcfVxW94Z8P3KdHQ7eT3F5AF8UGnQ2552fFyNmmOp0Il60USH3cl42DqckkWcXsq6ZcGRuqhoU79IQdNVdSyMpm+scNdn+Ps1OjfcGy3cX456GzKrvmZwbhvEBpK7WsjbfnXKJ8n1208FXWtM3H7XmZvxyDKhVb Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/26/26 17:47, Kalyazin, Nikita wrote: > From: Nikita Kalyazin > > Move the check for pinning closer to where the result is used. > No functional changes. > > Signed-off-by: Nikita Kalyazin > --- > mm/gup.c | 19 ++++++++----------- > 1 file changed, 8 insertions(+), 11 deletions(-) > > diff --git a/mm/gup.c b/mm/gup.c > index 9cad53acbc99..e72dacce3e34 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -2737,18 +2737,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked); > */ > static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags) > { > - bool reject_file_backed = false; > struct address_space *mapping; > unsigned long mapping_flags; > > - /* > - * If we aren't pinning then no problematic write can occur. A long term > - * pin is the most egregious case so this is the one we disallow. > - */ > - if ((flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) == > - (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) > - reject_file_backed = true; > - > /* We hold a folio reference, so we can safely access folio fields. */ > if (WARN_ON_ONCE(folio_test_slab(folio))) > return false; > @@ -2793,8 +2784,14 @@ static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags) > */ > if (secretmem_mapping(mapping)) > return false; > - /* The only remaining allowed file system is shmem. */ > - return !reject_file_backed || shmem_mapping(mapping); > + > + /* > + * If we aren't pinning then no problematic write can occur. A long term > + * pin is the most egregious case so this is the one we disallow. > + * Also check the only remaining allowed file system - shmem. > + */ > + return (flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) != > + (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE) || shmem_mapping(mapping); Best to keep this split and a bit more readable. /* * If we aren't pinning then no problematic write can occur. A writable * long term pin is the most egregious case, so this is the one we * allow only for ... */ if ((flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) != (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE) return true; /* ... hugetlb (which we allowed above already) and shared memory. */ return shmem_mapping(mapping); > } > > static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start, -- Cheers, David