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 B76A8C61DC2 for ; Thu, 27 Aug 2026 09:19:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AE41C6B0098; Thu, 27 Aug 2026 05:19:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ABBF86B0099; Thu, 27 Aug 2026 05:19:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9840A6B009B; Thu, 27 Aug 2026 05:19:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 736A86B0098 for ; Thu, 27 Aug 2026 05:19:15 -0400 (EDT) Received: from smtpin28.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id CC39240385 for ; Thu, 27 Aug 2026 09:19:14 +0000 (UTC) X-FDA: 85146500628.28.B6ACB32 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf09.hostedemail.com (Postfix) with ESMTP id E7E74140012 for ; Thu, 27 Aug 2026 09:19:12 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=bS7SQdIu; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf09.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787822353; 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=LixIDSU3TdZaT9dJGoqjplgLV7aXH03HF3B7mcClcig=; b=cr659rvnRlqsu9t2bJcmG5bghAphzQtS6m0qv2cHirvSnURGJDBehzDiaP9QXAXZyQ1LtB f6piTn4Ac5T3wb7BIOuw2/Fvn5bNXbJOccmwB7chYzTHXbt+37ugSAZDvgYsRvU1uUiIAD QSf3SSEFe6Hzr1X298yPDQ5vmkC9ckM= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787822353; b=SU3KvuMh37HZYXrAguZJKN4Bq5QpgKjh6INN0iX8q5hGapFY53OB6V4nFYwEk1GMmi2y0p iYW+Ale8YYVcTck++qfIZer555oIuTH5eyjC20C5QFJL3FHVxe3PRhPFoi/TyQ2dA3/10I 43yhsKe+7Jqq0yLuUzYzTaI4i7BcT9g= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=bS7SQdIu; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf09.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1D20140A0C; Thu, 27 Aug 2026 09:19:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 559941F000E9; Thu, 27 Aug 2026 09:19:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787822352; bh=LixIDSU3TdZaT9dJGoqjplgLV7aXH03HF3B7mcClcig=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=bS7SQdIuYyCMsB7a9rjTxHKZatdkuSikajfF/3NBtzQYqfjLjUeDr9272DHcot0XA W7uu5XJ8joem5jK0LM2pMGVV2U9pFfsmTYUq/Zurfkm7vLcOExivNA7SqfKg0OadbZ cmxCW6KRH09DsS9o6GS9zVE2pyPEFhPwG3ZwAXNwJe+4WNhIKsjMhvLUTUHHASXRrX GtDv7Tn1kx3Ha1nn3H41pIqLPjr+eE0fBZeSeJ6TdGZSn19iB50n3DFLosXwKECNnb fEETV8/HwlZn+PTIOsAF+Q6pTt/OKDXUSEUlE7fEiGchsqitgVBm426TwMvR2f5Ahu GjjQpnnms7Yzg== Message-ID: <01aae5b4-ee10-4601-8ddd-c9428e11d651@kernel.org> Date: Thu, 27 Aug 2026 11:19:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/6] userfaultfd: decouple fault reason from VMA flags To: Mike Rapoport Cc: Andrew Morton , Baolin Wang , Barry Song , Dev Jain , Hugh Dickins , Jann Horn , Jason Gunthorpe , John Hubbard , Jonathan Corbet , Lance Yang , "Liam R. Howlett" , Lorenzo Stoakes , Masami Hiramatsu , Mathieu Desnoyers , Michal Hocko , Muchun Song , Nico Pache , Oscar Salvador , Pedro Falcato , Peter Xu , Ryan Roberts , Shakeel Butt , Shuah Khan , Steven Rostedt , Suren Baghdasaryan , Usama Arif , Vlastimil Babka , Zi Yan , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org References: <20260823-uffd-vm-flags-v1-v1-0-3086981b33cf@kernel.org> <20260823-uffd-vm-flags-v1-v1-5-3086981b33cf@kernel.org> <5bb86e34-6196-4b50-b553-be2ff7c1fa32@kernel.org> 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E7E74140012 X-Stat-Signature: 9kcmhidqh3q8dfzaum8at7u9y6tknu66 X-Rspam-User: X-HE-Tag: 1787822352-731775 X-HE-Meta: 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 gHTVQaM/ 38w7ACXZdt1C8Yp7TFn4GzMNrqiWhJlpEcCJENg8V7vSW7g/IHQPl839Cnvh4wGrVjppcA2wUfGRJuyc1pGvPW2gOuJQ8rTz0PmBCdGZ43psZ0w7oqDRYq9M9yEu8MEIXzFIfpYJVJEtBykfecSfQXPRAZ/3FJd4uNwHXQx3ReWQ5Dh9EdnpdLL+v9QvJzlqvvb6GFFTqhcNZnI8Kgu+JyHvQ7Qp5NkNIcBN5gWDOGS7mE6K0zsNN9uCQjq8D5nIzOVkC Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/27/26 11:09, Mike Rapoport wrote: > On Thu, Aug 27, 2026 at 10:10:24AM +0200, David Hildenbrand (Arm) wrote: >> On 8/27/26 09:49, Mike Rapoport wrote: >>> >>> userfault_reason sounds better to me. >>> >>> It describes what kind of user fault we are handling and the 'fd' part has >>> nothing to do with it. >>> We do use uffd as a short name for the subsystem, but still most if not all >>> userfaultfd "external" APIs use userfault_ prefix. >>> >>> uf_ was an attempt to make it wee shorter :) >> >> Yeah, I got that; while uffd is a known acronym, the uf_ not so much (and also I >> wouldn't suggest it to become a thing, lol :) ) >> >> I've been wondering for a while whether it really should be called >> >> handle_userfault() >> >> And not instead >> >> handle_userfaultfd() > > The 'fd' part here sounds really weird :) > >> Or maybe even better >> >> handle_uffd_fault() > > That's somehow tautological, but maybe using uffd_ as prefix would make it > a "subsystem namespace", so tautology won't be as blunt: > > uffd_handle_fault() > >> And then have >> >> uffd_fault_reason > > Could work, yes. No strong feelings between this one and userfault_reason. I lean towards just calling stuff uffd consistently might be cleanest. -- Cheers, David