From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f48.google.com (mail-io1-f48.google.com [209.85.166.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F43112D771 for ; Tue, 16 Apr 2024 14:22:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713277378; cv=none; b=Mqnw7R24ryRXcrjRR7LypOfLmwkldXvl/2h2nEfBbi3cjsq2pCe0mL8XHEeEsPGlW/9mgmW8ZLsv49q2pFuj5XPmh5fsbDuCb8JyBPdIKEc4hKvv8v5hTt9UPigWxeBwneEeFJawyayUjwncFVWYMDl8S7PFm7k7kTffu9KoIKc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713277378; c=relaxed/simple; bh=KkhLAavCbkxsrMJ/g+XwkIEHN5YZSrFkpEyCXUbE+yw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=eWE2nzZ1ESzx8xxoCmjy68EqHB7Pp1BaODvLkyWSOrxed2oPeIgvqm2PETx1PGa0hKq433DPXn8YGCvdMpmLhDzuicS67Ny6Ky7r6sYoveXgtK8/9L3SWjgUyxv/qRcsekCkHLOgfSCU/EWg6bUVhA87+o8WtYAnLy28gN99cf0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=f/jiEdZ+; arc=none smtp.client-ip=209.85.166.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk 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="f/jiEdZ+" Received: by mail-io1-f48.google.com with SMTP id ca18e2360f4ac-7d9c78d7f98so3453739f.2 for ; Tue, 16 Apr 2024 07:22:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1713277375; x=1713882175; 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=f2fMNvEI24QOeRYU2Q7J/gXsOX3YqVKsrm8shQ/4hw8=; b=f/jiEdZ+puxc2vACOmS4yHpNeRWkI3dQKzuHhOJ2Jm4NtOW0nZnQEL1lpRX0w+U7Lw Y53F6Xsx+Tfqu+B9B+ooeOqUXGWeDkb7vw4o8hlJNQ9sJjj4izUqJCleldgaN/EN+6rs AXeYUqSIb7zRWPMygyCD2UZ2STWah8pJjpmHOODYVqxkQDnSxrtDr77gsYjRFNUdtdFK 015mqTE0d8V7vc4EL9iXMpwrTAw8HzwH43XyLqolx1nAIv4eu66vIt4swyujee/K7MNr EC3rKLEM/mdxK/tZOLTlgAiZFr68CEiVx9uAZvzzmCeMZX/UKUBn2P/95uycq0i+4O7v r/xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713277375; x=1713882175; 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=f2fMNvEI24QOeRYU2Q7J/gXsOX3YqVKsrm8shQ/4hw8=; b=J27wPB6yO71a1+rbo7F/N0hXAGyXvTvJ+wOCbK2olt7loN+/OSDyFsG8+2lEe210Xz EVuz4+LGXRvQNDBsty+J7Z+1DrLtLLSQApnq+yEVfGpvtLGvjbZwkNyhX9h4PqcvIbkB iRPw3CnOQwjl2nyTVjjAZm6aeGRnGQP+Hy1z7OQ99rs5V4jHjczN3arJqO35okBCvA9O Ont4MF9YLpqMRIw3xE55uMCnkSPD/BDRUQ4sroD/tngYNKAGQp5Bq7aogUetYrj/8sCV LwAzMQpFQcsB5dvLcmOj7cVRtAy/wmQkSnHonlrX2qO1JB3GKm4nwbnMBTu4qlr1HK7g 240Q== X-Forwarded-Encrypted: i=1; AJvYcCU2NKpPXxOZb4emWfEomAA14yBYkdFwpd9SAqN0aLP/LPnJqpnfeh0qCKtU5p0wPm8Lh2h43fw7QmwL4H2FRTDjGIUK4M/j4hoeP6s= X-Gm-Message-State: AOJu0YxnT5HNmFyVUD5jzsw5T7gwasAPWBDHHYdDtaZ2cVrWSdrKwob7 y6LwULMEZ1HPCtuwjtbYbIzWY34CYQCP8tUZZpiswfP4Dov/+HcARAtvsaQaS3GTRaSXXUd47IG Q X-Google-Smtp-Source: AGHT+IFHQy//HeRmRxLtJ547eHKcIHb0Q1z3xF2183VnfWuSC2U/dBI0HyNuCFx3DBhEW9NP4bivYA== X-Received: by 2002:a05:6602:4ed7:b0:7d5:ddc8:504d with SMTP id gk23-20020a0566024ed700b007d5ddc8504dmr12062089iob.0.1713277375372; Tue, 16 Apr 2024 07:22:55 -0700 (PDT) Received: from [192.168.1.116] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id b9-20020a05660214c900b007d95d6ef5c0sm1671531iow.9.2024.04.16.07.22.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Apr 2024 07:22:54 -0700 (PDT) Message-ID: Date: Tue, 16 Apr 2024 08:22:54 -0600 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: API break, sysfs "capability" file Content-Language: en-US To: Lennart Poettering Cc: Christoph Hellwig , Keith Busch , Linux regressions mailing list , linux-block@vger.kernel.org, LKML References: <54e3c969-3ee8-40d8-91d9-9b9402001d27@leemhuis.info> <20240409141531.GB21514@lst.de> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/16/24 8:18 AM, Lennart Poettering wrote: > On Di, 09.04.24 09:17, Jens Axboe (axboe@kernel.dk) wrote: > >> On 4/9/24 8:15 AM, Christoph Hellwig wrote: >>> On Tue, Apr 09, 2024 at 10:19:09AM +0200, Lennart Poettering wrote: >>>> All I am looking for is a very simple test that returns me a boolean: >>>> is there kernel-level partition scanning enabled on this device or >>>> not. >>> >>> And we can add a trivial sysfs attribute for that. >> >> And I think we should. I don't know what was being smoked adding a sysfs >> interface that exposed internal flag values - and honestly what was >> being smoked to rely on that, but I think it's fair to say that the >> majority of the fuckup here is on the kernel side. > > Yeah, it's a shitty interface, the kernel is rich in that. But it was > excessively well documented, better in fact than almost all other > kernel interfaces: > > ? https://www.kernel.org/doc/html/v5.16/block/capability.html ? > > If you document something on so much detail in the API docs, how do > you expect this *not* to be relied on by userspace. This is _internal_ documentation, not user ABI documentation. The fact that it's talking about internal flag values should make that clear, though I can definitely see how that's just badly exposed along with other things that document things that users/admins could care about. -- Jens Axboe