From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A07DB3F23A3 for ; Mon, 18 May 2026 15:32:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779118332; cv=none; b=Y6nMD4CKlUfryKKv0kh5TesIMzhafU0kcbpZ2o5OsUjfk7A0KAPEL8TfHQEIU8Eq3I08p8euv5I7AO5CadpM4jjJnfTx/rRCf/EtPd6YCESsVviupZLke5dtA/DPUQM3GGO/NFWsaRYzP0XF/t1JDqHMwKOqTMdQ0h/Gm6+5t+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779118332; c=relaxed/simple; bh=eYfaeXBVhks16M1HxsgZAfbmDLr7rWnLBaeuSPVbjYc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=h1ElPvOXX8m9vF2+FDHLZrNlJZhamer8p7SofZVx7Z1Me1WStGgqSC1/mA7g41a+cN133oxRsyOnmUWPZcJMzWEbMgV2yTtJNxM1Mn/FDCnnr/z4gCV082+C+f5koeoDH/9ru/uFD8u6/kPiECk4+2bNA11Jxe4MO/LZ7TRcIXU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QxbeVIV8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QxbeVIV8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC1B3C2BCB7; Mon, 18 May 2026 15:32:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779118332; bh=eYfaeXBVhks16M1HxsgZAfbmDLr7rWnLBaeuSPVbjYc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=QxbeVIV8ieAd/bGrixCsErV+spuldnExgSaAxp/vMCIO1rF53+wf+zR8sbaJFjaUX neGg7Kvq2dXDGUzywxQisuPuhPWyBVqN1jMxdHpc5Agh12WTmnZUSeTTpZY7ElGSId Uvl/+EqErnKiNym+bQdOMst2lEQRd+UrEIv0ePf4Uv3FdH0zpEs+NgO9jbzqdX2Vti US7LjOzNPNo1Y5zFbdCfYIKf+ufSKZXV6viV8d0C9zyaUJZ2iWZLXlyQyYvr6oZexj Gqu0jfIIy1YDJrW09ghTCy/78qBw7BevrTu4XfKpioyAVZ6VuMvyubAOQPFbAu6nWF GIFGJgZqP3NyA== Message-ID: <5e168a17-b395-4586-8b81-0a405560f8e5@kernel.org> Date: Mon, 18 May 2026 17:32:06 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] mm: add bytes_to_page_end() helper To: =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= Cc: Lorenzo Stoakes , David Laight , Yury Norov , Thorsten Blum , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Yury Norov , Rasmus Villemoes , Andy Shevchenko , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20260517123428.1181981-4-thorsten.blum@linux.dev> <20260517123428.1181981-5-thorsten.blum@linux.dev> <20260518100933.6bfe5b8f@pumpkin> <8d7dc7e2-d52b-4903-ad1b-3185b393ba24@kernel.org> <20260518162257-ef48fdfb-21a2-4024-93fd-6ed423ae426c@linutronix.de> <83606b46-6a2d-4904-8b05-b0de9da741f0@kernel.org> <20260518164802-2b27ec0f-2ee5-43d9-881a-cd41251c7371@linutronix.de> 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: <20260518164802-2b27ec0f-2ee5-43d9-881a-cd41251c7371@linutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/18/26 16:52, Thomas Weißschuh wrote: > On Mon, May 18, 2026 at 04:41:38PM +0200, David Hildenbrand (Arm) wrote: >> On 5/18/26 16:29, Thomas Weißschuh wrote: >>> >>> The idea behind the vdso/ header namespace is that it can be used from >>> vDSO userspace code. A weird middleground between linux/*.h and uapi/linux/*.h. >>> Also in a compat vDSO anything depending on BITS_PER_LONG is wrong, and instead >>> __BITS_PER_LONG needs to be used. A bunch of kconfig settings, like >>> CONFIG_64BIT can also be off. Additionally internal kernel symbols are >>> obviously not reachable from vDSO code. >>> >>> Regular kernel code should not use the vdso/ namespace but instead use the >>> regular linux/ headers, which in turn include the corresponding vdso/ one. >> >> offset_in_page() is that trivial that I don't see how it shouldn't just go next >> to PAGE_SIZE / PAGE_MASK, though? > > Yes, IMO it could go into vdso/page.h. The related offset_in_folio() which is > defined right next to offset_in_page() however can not go there, as folios do > not exist in the vDSO userspace context. yes, folio stuff should not go in there indeed. > > Personally I don't care about where this goes and just wanted to clarify the > background of the vDSO headers. Yes, thanks! -- Cheers, David