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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 F2B7CCD4851 for ; Tue, 12 May 2026 06:25:44 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4gF66H1SFLz2yhD; Tue, 12 May 2026 16:25:43 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=172.105.4.254 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1778567143; cv=none; b=NgnV7i4J1otPiTFipbQLMs5cLaJN/OZDCBQBl6z9JBldRVVVo107pMOZ4IWcoW0+jrOX3YZOgn/YV4B8V9rAl7l3jZ7K2KBJjxQjPib+9FUkDJ8HDt4gkXcVbuESdn2j3TjK7A/5UnuimNxKTJ30VUMdcQq7LUKHLMz63gXVNMqNUY/SH7Bl3s8Jb3pt0ZcQP6SX5jSXSN2jMxxrS8TT32Lh6aItfYnMVhvlbudgRTctzpQqQW1BhM31kzN/joyN5O/BcEkTcVlo9BdNlsRYhgDKL+9CBBwyP058QbGGpZemfrcrFrJvzQFmhDMOHZ7uoMrZHECvyFLxTTyVYog8ZQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1778567143; c=relaxed/relaxed; bh=f1acAZ/Sh8ScpKdVt9NyUqWQyZ/FLoN5Ha7ECc0GdNA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=XQKCHqoa2iRbsKrdKb3vUovBMsAiFzia8guZRKaRLm8F26qk3kn3fEUNbQt6n7YS+ycsuykeR5yJNWf4NN80IVRfNIXkxDmcZVZS3YbrrwfPK5q5hn4jCF/Gp9gcb7PpU+RhMDriC+cY06mk0lrqt1wz9h8ThDeQ/PGH6mWEhjIxHtKIAhnc2Pdlk4053ifD9M+FvW/c9wsyTkV+NjJq20OIBpf7+WWWHcN8xvhpQr4i/qBU67EbQ5ZUQxWYEQLXgszYObveZvBY3uIsjEty0L2aLil5Dy8ksy/Ui+gnxEuams1RMNtTxijOW1eNaD56MFKfVdod/aim5rrhGHhQ8w== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=KPJcQ42l; dkim-atps=neutral; spf=pass (client-ip=172.105.4.254; helo=tor.source.kernel.org; envelope-from=david@kernel.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=KPJcQ42l; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=172.105.4.254; helo=tor.source.kernel.org; envelope-from=david@kernel.org; receiver=lists.ozlabs.org) Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4gF66F4rdrz2yQn for ; Tue, 12 May 2026 16:25:41 +1000 (AEST) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id C55D060123; Tue, 12 May 2026 06:25:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 390C1C2BCF7; Tue, 12 May 2026 06:25:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778567138; bh=bvbc8NXu/FH7JnxQJ63NcUmUspxbFGn5COPiYbadr3A=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KPJcQ42lqoBcaETRv9s+IzNGz//Ivc3JXk62CLGniVddCcT7ZanylFrpu5HvNcC72 8YEE0SbmT1B3xZ4lA1+2Qsjkh1eXEslJ/tY8CMEED1WfQJQ14v9wTsLocbwC9h3gCL jccrj5ez6EJPBy2q3LVN/R1TErMfH+SvCgv2cpqkH611/p+ILQTxG6cVhb0ucvazyI F90DLpobyL8sA1ptsK1UAA3yb7vOWSkrGWgpanWP2o/5xSobicfFs8pvRks7wYEXMK 5dQVpp0DW6QfrHV0VstIURYs3Hxu6a8pKNDYl/Wc2Wo+kLpw1dZZjii2Jp2ju/Itia HTqfliANKU/Zg== Message-ID: <9171623c-4775-49e9-bc05-3ecf1a81c7bb@kernel.org> Date: Tue, 12 May 2026 08:25:31 +0200 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drivers/base/memory: make memory block get/put explicit To: Muchun Song Cc: Muchun Song , Oscar Salvador , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , linux-mm@kvack.org, driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org References: <2841f424-580c-48c6-bb26-de30e4397b7f@kernel.org> <3234B4D3-8202-4E79-B85B-8B6373BB76F6@linux.dev> 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: 8bit On 5/12/26 05:11, Muchun Song wrote: > > >> On May 11, 2026, at 21:23, Muchun Song wrote: >> >> >> >>> >>> On 5/11/26 13:18, Muchun Song wrote: >>> >>> Better mention some of the other changes here, like removing find_memory_block(). >> >> Will do. >> >>> >>> [...] >>> >>> >>> While at it, please drop the "extern". >> >> OK. >> >>> >>> >>> Would guards come in handy here? >> >> You mean to introduce something like: >> >> scoped_guard(memory_block, id) { >> } >> >> Right? If yes, I will give it a try. > > Hi David, Hi, > > Did I get that right? I assume so, but it's indeed rather ugly. ... in particular the CLASS and scoped_class() thingies are pretty intuitive. I thought we could use guard()/scoped_guard(), but reading the details, it's mostly for locks only. There is only one users of scoped_class in the tree (overlayfs). Maybe, if we would do this properly, we would actually provide our own wrappers, like MEMORY_BLOCK scoped_memory_block not even providing "memory_block_get", as that would be implicit. Like MEMORY_BLOCK(mem)(block_id); // the second () is confusing scoped_memory_block(mem, block_id) { } But that requires more thought, and I don't really know what the best practice is there ... So thanks for trying, but let's leave it as is for now. -- Cheers, David