From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="KqMZiWIu" Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADEBACB for ; Mon, 4 Dec 2023 14:09:49 -0800 (PST) Received: by mail-pg1-x52f.google.com with SMTP id 41be03b00d2f7-5c67fdbe7d4so125703a12.0 for ; Mon, 04 Dec 2023 14:09:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1701727789; x=1702332589; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=N7YVZRS1Yk2p3iV3hbb4MrgXwpXbi4TeT5VGkU/u+Jk=; b=KqMZiWIu6Huk1KRv62/VLR70dCPjpFds0G8v2g0RW8hC/DSworJnr6ZLlYFO2j3c88 hYt0tr1acI6wUHCWFiu7iY1jpRvkg1u8+yu9FZd5fuC8Zf+jlvjquBCuceBwUmcx8e6C tQxq1a6mza04HO9xXTeS620tIojtLyJHI29WYy2ChNCSz01NTw+772Nd0CqqV+eXo5/v WPYcaPYgTu3/7VJW0ooRbRSH56JUPEQLJeN/ZqZ2X8+G/ImlxtpTe2tJ/rKD6wGGTPU/ MqFenhCRgBmedtBNgv8emQ5Tjr/YO+/jCl1UcYKdG7J4J/STnzMJ0jN25nDqFX/C4VI/ Xz1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701727789; x=1702332589; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=N7YVZRS1Yk2p3iV3hbb4MrgXwpXbi4TeT5VGkU/u+Jk=; b=TkNcgYhHRXatQMxwlp6yVCkyN4ItjyLZWJnjC/18U2/PgBz5+LfGB4phWY7Q4A0iHp xIPU/KuHPVPJKOuHVhiJeCo+RxzcjWg5dsPNR4x8BIkg3Cci8MpuOnqCCSHUQf3kN25Q 9m/lemRFp2eQRsSMdtW3Y19gFlZ+QvxjdNO3DIEcCELNJ1yTbTpCpTUnWiafp8coBS+t 8x1hAUIeUWcDLcOA8AB68/ceqj18TlEf2I6TV3QyjFCVLiEb5LY9nn5i71wLd/TEIas3 KbyCHSfOrYlj/WHHdLANEYDE/fJjj7accTw4D1TayDlPwlSD4xc43Hm3vo3KKTRMS4t2 u01g== X-Gm-Message-State: AOJu0YxhC8kbgmbWf9JvVmjUohaOKzes8NTuoJdJl7+dhXmCXgVY14nM fFp7itlQY8yVj9kFPkksq5J/eQ== X-Google-Smtp-Source: AGHT+IHDv1b42RKXKN4tRifZv0mEX5EckA+D3oEFHeJfjju4L9UJaftPOWecVThY8YBY1KMQIFUJ4A== X-Received: by 2002:a17:903:234a:b0:1d0:b693:ae30 with SMTP id c10-20020a170903234a00b001d0b693ae30mr2493966plh.6.1701727789078; Mon, 04 Dec 2023 14:09:49 -0800 (PST) Received: from [192.168.1.150] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id t4-20020a170902bc4400b001bf11cf2e21sm5844131plz.210.2023.12.04.14.09.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 Dec 2023 14:09:46 -0800 (PST) Message-ID: Date: Mon, 4 Dec 2023 15:09:44 -0700 Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] Allow a kthread to declare that it calls task_work_run() Content-Language: en-US To: NeilBrown Cc: Al Viro , Christian Brauner , Oleg Nesterov , Chuck Lever , Jeff Layton , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org References: <20231204014042.6754-1-neilb@suse.de> <20231204014042.6754-2-neilb@suse.de> <170172377302.7109.11739406555273171485@noble.neil.brown.name> From: Jens Axboe In-Reply-To: <170172377302.7109.11739406555273171485@noble.neil.brown.name> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/4/23 2:02 PM, NeilBrown wrote: > It isn't clear to me what _GPL is appropriate, but maybe the rules > changed since last I looked..... are there rules? > > My reasoning was that the call is effectively part of the user-space > ABI. A user-space process can call this trivially by invoking any > system call. The user-space ABI is explicitly a boundary which the GPL > does not cross. So it doesn't seem appropriate to prevent non-GPL > kernel code from doing something that non-GPL user-space code can > trivially do. By that reasoning, basically everything in the kernel should be non-GPL marked. And while task_work can get used by the application, it happens only indirectly or implicitly. So I don't think this reasoning is sound at all, it's not an exported ABI or API by itself. For me, the more core of an export it is, the stronger the reason it should be GPL. FWIW, I don't think exporting task_work functionality is a good idea in the first place, but if there's a strong reason to do so, it should most certainly not be accessible to non-GPL modules. Basically NO new export should be non-GPL. -- Jens Axboe