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 EA6B0CA0EFF for ; Thu, 21 Aug 2025 20:29:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 40ED38E004C; Thu, 21 Aug 2025 16:29:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3BF8B8E0048; Thu, 21 Aug 2025 16:29:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2AE158E004C; Thu, 21 Aug 2025 16:29:59 -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 192038E0048 for ; Thu, 21 Aug 2025 16:29:59 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id BF2DB160520 for ; Thu, 21 Aug 2025 20:29:58 +0000 (UTC) X-FDA: 83801906076.13.17B87AB Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf23.hostedemail.com (Postfix) with ESMTP id D86BD140004 for ; Thu, 21 Aug 2025 20:29:56 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=redhat.com (policy=quarantine); spf=pass (imf23.hostedemail.com: domain of "SRS0=upZg=3B=redhat.com=david@kernel.org" designates 172.234.252.31 as permitted sender) smtp.mailfrom="SRS0=upZg=3B=redhat.com=david@kernel.org" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755808197; 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; bh=4yLFBFPucSphBvh8G1wo9pC+YhZFsib1p8DH3Ndsgg8=; b=eHtHxhd6gu2dpyYR+1a9JsjQG5wfIqX7y65CFH2lEG3XrxoxWtp/xG9ppZtTnXhXbsylT8 NO254THxoseSwUvVr9DSF7vyiX6CV+CTlmW9a6CekCNmvyDcancF0OQlwySLEwpggJrcLd TgxRazjOfj2TtkPLRllmQgyMwYuZzmk= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=redhat.com (policy=quarantine); spf=pass (imf23.hostedemail.com: domain of "SRS0=upZg=3B=redhat.com=david@kernel.org" designates 172.234.252.31 as permitted sender) smtp.mailfrom="SRS0=upZg=3B=redhat.com=david@kernel.org" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755808197; a=rsa-sha256; cv=none; b=CKkMHWxmBVgYmjFCNQj7/B1dIeBoyHv6g0LNdS5437wa9Q9Kgk4iEmX+CU4l1CjBGrLbFH 1X3NO/YW7WLGg4gVVHh80uSYh3/kikrYqXXPd7obwas/wvF6gA7T5nCBOBQMA1P1L8uQ7F RcmAkEhlt90eS56234/R9yD3bEslin0= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 8F9F5449B7; Thu, 21 Aug 2025 20:29:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AC82C4CEF4; Thu, 21 Aug 2025 20:29:43 +0000 (UTC) Message-ID: <2926d7d9-b44e-40c0-b05d-8c42e99c511d@redhat.com> Date: Thu, 21 Aug 2025 22:29:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 31/35] crypto: remove nth_page() usage within SG entry To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, Herbert Xu , "David S. Miller" , Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, "Liam R. Howlett" , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Lorenzo Stoakes , Marco Elver , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan References: <20250821200701.1329277-1-david@redhat.com> <20250821200701.1329277-32-david@redhat.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: njs7ew9gdana1kyypybmnsr4ihm3zfii X-Rspam-User: X-Rspamd-Queue-Id: D86BD140004 X-Rspamd-Pre-Result: action=add header; module=dmarc; Action set by DMARC X-Rspamd-Server: rspam05 X-Rspam: Yes X-HE-Tag: 1755808196-290368 X-HE-Meta: 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 i6we0y1Z 54ZEqmpDay9VEmLwBTrsfkKQ/ZAX58G0GAuy83Ki9ZO8l7MJZX66KslwXvD9PQk6uh595ANPzCqrcgl2X3IBE9Q/o5+PdXK+IlweGHGdhdCdn/iaMBhq+TFhLh8FD9HGuiT4geRR8i/xxT8TLzT4POLvGOfqMzRC2t3I0/HvIkU3G1gcAyie1+mVCHI36z84EQ4jSu1vLJojHGKym3cKektlkNCF2jvLrC8U6JDTzFvG17P8DBjyKphsiIPsZ2REDlqljR0C0p+oP9r+I4iIX2F/AV1PBSE6SMkFb9CEq/xFadCHwWMma4TMVBd+6bULxRsysXVSjs5PMu3fPPzSA41gcQtn4ROXQrsJOFhbk1tyKlqd2+hg9w7DBBVZAcV5Ce5yuueTtcDqR2KV3H2EQH2XTFEsGDcWcMt6HH52a5WNb3w2y8i/SHS/E0BRpmikNrUr1tJj+odGyxAzX7n84s3UCChHVWbUAOc2H 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: List-Subscribe: List-Unsubscribe: On 21.08.25 22:24, Linus Torvalds wrote: > On Thu, 21 Aug 2025 at 16:08, David Hildenbrand wrote: >> >> - page = nth_page(page, offset >> PAGE_SHIFT); >> + page += offset / PAGE_SIZE; > > Please keep the " >> PAGE_SHIFT" form. No strong opinion. I was primarily doing it to get rid of (in other cases) the parentheses. Like in patch #29 - /* Assumption: contiguous pages can be accessed as "page + i" */ - page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); + page = sg_page(sg) + *offset / PAGE_SIZE; > > Is "offset" unsigned? Yes it is, But I had to look at the source code > to make sure, because it wasn't locally obvious from the patch. And > I'd rather we keep a pattern that is "safe", in that it doesn't > generate strange code if the value might be a 's64' (eg loff_t) on > 32-bit architectures. > > Because doing a 64-bit shift on x86-32 is like three cycles. Doing a > 64-bit signed division by a simple constant is something like ten > strange instructions even if the end result is only 32-bit. I would have thought that the compiler is smart enough to optimize that? PAGE_SIZE is a constant. > > And again - not the case *here*, but just a general "let's keep to one > pattern", and the shift pattern is simply the better choice. It's a wild mixture, but I can keep doing what we already do in these cases. -- Cheers David / dhildenb