From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fra-out-009.esa.eu-central-1.outbound.mail-perimeter.amazon.com (fra-out-009.esa.eu-central-1.outbound.mail-perimeter.amazon.com [3.64.237.68]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7E49D3939B0; Fri, 6 Mar 2026 12:49:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=3.64.237.68 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772801362; cv=none; b=JT5Ar+pQuUB9r7Lrvpxb88O8Z6egJKyR2GbfQt5gBTWHA2O/W3c2gMHW1T04/oo9IQKshysIGw5SUSaCQSnqXnx1/Gw6Lui1KGv5AC5RBmvl+sIY2It5F1MQg/lVmWZh0Tc4YDxzdKU9Bo3DyvjYeVys33s5UC+2AyGoAmowqHw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772801362; c=relaxed/simple; bh=LR/k1rHM5LZ3hLuYrcHnIwjUhmNmnXoE6cKE5i5BZnc=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=E8OpJCIKpUTxQytn1Nhg7bDuJwvz0zo25b44sW4N1lZtLgNVp+mPW5akQAQuzYn733Voj3RBJP3oPYJ8TMA7lg0ZaMcrdM/yStdlCZAblT0vWd/lJPhgMfLAEaoZHDc9+xscEKyshLSqmvpN9TFNzep+KNG6K5cmEOyz+t4inu4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.uk; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=RGDZR/qi; arc=none smtp.client-ip=3.64.237.68 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="RGDZR/qi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1772801360; x=1804337360; h=message-id:date:mime-version:reply-to:subject:to:cc: references:from:in-reply-to:content-transfer-encoding; bh=bRMHQdQ5GfQ08jWBNyGRBN4vXmA9+fBBCWCkl04FNjQ=; b=RGDZR/qij9TjI+VazrRUViMMf/eqy0kia7n7lFKgerHRVadWO6wR+VNT WPekJ+l9DbZufHQLBhkhMl0nl8MjVJEmNeeniWQALuLo+qUaqZYSo7MRS UpNEJlOpSAcA7cAxEy1obY944zV/DLpDH7eaJGNupCDJWrksdF23St++X IH05y5ao3+//u+KHk1G81cohkdtAlhuEYbJ36YnuAzovDKB05lQRLwWmv RjsKaNPSzpvrE1PL+HosVpEL4m6otiVjE+Ndpo2O+8/fB9x1hqfOxXGIb BdAfTB9Ewuw2GYp1dFWUy1HEHbHtnM2aslMv9/Bgcw9od+sLFMLJ2+ivs A==; X-CSE-ConnectionGUID: +CBc8LTUTFyKU3vgne5J+A== X-CSE-MsgGUID: SsgvaCDKTQyRTYkBnx7yEA== X-IronPort-AV: E=Sophos;i="6.23,104,1770595200"; d="scan'208";a="10334046" Received: from ip-10-6-6-97.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.6.97]) by internal-fra-out-009.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2026 12:49:17 +0000 Received: from EX19MTAEUC001.ant.amazon.com [54.240.197.225:27792] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.8.50:2525] with esmtp (Farcaster) id 3c65634d-d2ee-42b8-a0db-5e2cd1d9a376; Fri, 6 Mar 2026 12:49:17 +0000 (UTC) X-Farcaster-Flow-ID: 3c65634d-d2ee-42b8-a0db-5e2cd1d9a376 Received: from EX19D005EUB003.ant.amazon.com (10.252.51.31) by EX19MTAEUC001.ant.amazon.com (10.252.51.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.37; Fri, 6 Mar 2026 12:49:14 +0000 Received: from [192.168.2.180] (10.106.83.26) by EX19D005EUB003.ant.amazon.com (10.252.51.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.37; Fri, 6 Mar 2026 12:49:09 +0000 Message-ID: Date: Fri, 6 Mar 2026 12:49:08 +0000 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: Subject: Re: [PATCH v10 04/15] mm/gup: drop local variable in gup_fast_folio_allowed To: "David Hildenbrand (Arm)" , "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> Content-Language: en-US From: Nikita Kalyazin In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: EX19D015EUB002.ant.amazon.com (10.252.51.123) To EX19D005EUB003.ant.amazon.com (10.252.51.31) On 05/03/2026 19:07, David Hildenbrand (Arm) wrote: > 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); Makes sense, thank you! > >> } >> >> static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start, > > > -- > Cheers, > > David 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 9A603FCC9A4 for ; Tue, 10 Mar 2026 00:00:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:Reply-To:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To: Subject:MIME-Version:Date:Message-ID:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2TOliWXMbuYh0SR4aOxw2QrGkTeWIw8InO2gSbWnZig=; b=UVvkCUVJRTVSus UOidl1MFuRlceAVuBQ8RGyQvKvaLanfhrNgnfjAwDqvaeNWswedTZB03aPRZYr0RdvEIOckc5z/2l NEL61DD07+KoZS5sx+5TWOY66dsz3zs296XeQDSDAGXKIzcnyvhkUbwywL7Qc9zCkjXCsmOQggBdM y3ZyhzCzy+ZVXsDlzTLSP0oslTfONLZbctWBKotCzIjpaQE0kWtobQyTXFUjv5e1FLTo+SNl1QDCU oGjQ7WfzD25uWDdQKt5OqlvlfS8s6l9ntGfqpFtKwjEmiueM71uxVp4roHxPSbZM7e2fcwM0VWozN 2/dzh3jsPT32DbllKYlg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vzkWX-00000008KXR-2uMI; Tue, 10 Mar 2026 00:00:33 +0000 Received: from fra-out-009.esa.eu-central-1.outbound.mail-perimeter.amazon.com ([3.64.237.68]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vyUcJ-00000003gKY-2tPA; Fri, 06 Mar 2026 12:49:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1772801359; x=1804337359; h=message-id:date:mime-version:reply-to:subject:to:cc: references:from:in-reply-to:content-transfer-encoding; bh=bRMHQdQ5GfQ08jWBNyGRBN4vXmA9+fBBCWCkl04FNjQ=; b=Ay0F96w3RVw2nm9FgxFQd0sC5fktbIchaKwSfO23sZWwD7ihM2x2wRvT NoKdM31efeHTiGLW9DMguDe/Kb68smNDT1K10yhnwJoTiAzCa05BT+6FD A+J+mTdjwVFGVQLz76hoa0J9Je0mjftPrNbSOq0meXlU1s/s9l7QEifsX jyR0G8XVNrAzoGcyeravQ7n4UrxLrS0pRljOw3yw8Ozi/ciEBUCUuL8JZ WkBlymruZ6q/BE0WZSyw/mAXwhXhxNUrzbnC2FSyqE6i3LrsGi/2fz612 r35wqmeOklrk6CS6TJTw7FCKrYi/13CM80qoesc9ZQY/LQt7ivvLAvMPj g==; X-CSE-ConnectionGUID: +CBc8LTUTFyKU3vgne5J+A== X-CSE-MsgGUID: SsgvaCDKTQyRTYkBnx7yEA== X-IronPort-AV: E=Sophos;i="6.23,104,1770595200"; d="scan'208";a="10334046" Received: from ip-10-6-6-97.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.6.97]) by internal-fra-out-009.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Mar 2026 12:49:17 +0000 Received: from EX19MTAEUC001.ant.amazon.com [54.240.197.225:27792] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.8.50:2525] with esmtp (Farcaster) id 3c65634d-d2ee-42b8-a0db-5e2cd1d9a376; Fri, 6 Mar 2026 12:49:17 +0000 (UTC) X-Farcaster-Flow-ID: 3c65634d-d2ee-42b8-a0db-5e2cd1d9a376 Received: from EX19D005EUB003.ant.amazon.com (10.252.51.31) by EX19MTAEUC001.ant.amazon.com (10.252.51.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.37; Fri, 6 Mar 2026 12:49:14 +0000 Received: from [192.168.2.180] (10.106.83.26) by EX19D005EUB003.ant.amazon.com (10.252.51.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.37; Fri, 6 Mar 2026 12:49:09 +0000 Message-ID: Date: Fri, 6 Mar 2026 12:49:08 +0000 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: "David Hildenbrand (Arm)" , "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> Content-Language: en-US From: Nikita Kalyazin In-Reply-To: X-Originating-IP: [10.106.83.26] X-ClientProxiedBy: EX19D015EUB002.ant.amazon.com (10.252.51.123) To EX19D005EUB003.ant.amazon.com (10.252.51.31) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260306_044920_022478_5E72C684 X-CRM114-Status: GOOD ( 17.01 ) X-Mailman-Approved-At: Mon, 09 Mar 2026 17:00:27 -0700 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: kalyazin@amazon.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 05/03/2026 19:07, David Hildenbrand (Arm) wrote: > 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); Makes sense, thank you! > >> } >> >> static void __maybe_unused gup_fast_undo_dev_pagemap(int *nr, int nr_start, > > > -- > Cheers, > > David _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv