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 36A82381AD; Mon, 8 Apr 2024 22:41:11 +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=1712616072; cv=none; b=mKOIp4M3opmCBEE6VU6ex8VJ7aNE7SqM2IPTsJyPgUydlZdxgY9iMrv+9VCKFcHAMvLyiMJ8r88un1OGPirceHmRd4hUnnMcFWaxZdws6sv/vKvNm1HJeHNCfjGtv4yvpfNkVb6LbM5niQzJnnO0uN1px1gFVzGO2xGJnfndPNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712616072; c=relaxed/simple; bh=uq+iuZWFJeFjkBxY9LAE5aFyS6mStouA09bvmO1Xduk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Lwl0glV8XOqkOT7OpFkq9iwQ5Z7KPOvWpLE87rqFaoZ6qk8BZp03wjNSFDQr5uRrbRMf+NnLF8v9TFllhmPk9eg1bMcdIWUtBqzUer9MZ3guW4QW2GubZu3tc29goa/9NiYKy1urbt63m+OH3GoUcVzrN4obDcURGvXEgZhgZK4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tEKHOMvY; 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="tEKHOMvY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5515EC433C7; Mon, 8 Apr 2024 22:41:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712616071; bh=uq+iuZWFJeFjkBxY9LAE5aFyS6mStouA09bvmO1Xduk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tEKHOMvYUum8eYAsZcQaVxVMVx/WPybI5+LjUwRKgwoGCBYs2NiqfITsfLF4GRg3j jWAR4EygzbUY1QA4UGSEzrD+NJ6/z62iXMf84eFyoIS+Thhla8Yi+U3Z02J9Bj+Uge RF9hQnEgU0PJu6lTl+lgJPX/X3rs0ZLPJ5QueHi9EE5pyMmB7NT4WZAB5SX2q+ULcV vTy6EpqL/qEXpdlP/DlBG+fQJC6UYxv34rGaPThX9gPCrGxclzl7mZIZq/Z8LZlnMY yq0NU0O/sj12i9qFtSaVeJkpHzU9X7+c7nVKNzaQFO2nGtUQtBOsx1ps4hy16VHp3x lclfJetttHdaw== Date: Mon, 8 Apr 2024 16:41:08 -0600 From: Keith Busch To: Lennart Poettering Cc: Linux regressions mailing list , Christoph Hellwig , linux-block@vger.kernel.org, LKML , Jens Axboe Subject: Re: API break, sysfs "capability" file Message-ID: References: <54e3c969-3ee8-40d8-91d9-9b9402001d27@leemhuis.info> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Apr 08, 2024 at 10:23:49PM +0200, Lennart Poettering wrote: > Not sure how this is salvageable. This is just seriously fucked > up. What now? > > It has been proposed to use the "range_ext" sysfs attr instead as a > hint if partition scanning is available or not. But it's entirely > undocumented. Is this something that will remain stable? (I mean, > whether something is documented or not apparently has no effect on the > stability of an API anyway, so I guess it's equally shaky as the > capability sysattr? Is any of the block device sysfs interfaces > actually stable or can they change any time?) The "ext_range" attribute does look like an appropriate proxy for the attribute, but indeed, it's not well documented. Looking at the history of the documentation you had been relying on, it appears that was submitted with good intentions (9243c6f3e012a92d), but it itself changed values, acknowledging the instability of this interface. So what to do? If documentation is all that's preventing "ext_range" from replacing you're previous usage, then let's add it in the Documentation/ABI/stable/sysfs-block. It's been there since 2008, so that seems like a reliable attribute to put there.