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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C245BC433F5 for ; Tue, 30 Nov 2021 06:49:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238811AbhK3GxR (ORCPT ); Tue, 30 Nov 2021 01:53:17 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:48196 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233919AbhK3GxP (ORCPT ); Tue, 30 Nov 2021 01:53:15 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 6A8DD1FD2F; Tue, 30 Nov 2021 06:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1638254995; h=from:from:reply-to: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; bh=hPMSjAKUvWrxkyumPjAUQRt3wWFJYgrlV6wdEOiht/I=; b=PGJVRHICcc8IILBvJDuzDgZwDz6Qkh7yf850L7I7o31/zrc3I6oqwcOO8p6d5ZNbc69cHs U9T1FZuLMXt7tX/lB3+VD+UniOqFlU4YPlsmIfAYxLajulZeGdgM8BAW0KDymcmSHJsiiY 9heMsTkTuBAeVFI1dNoO/ZExDPR++Rk= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1638254995; h=from:from:reply-to: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; bh=hPMSjAKUvWrxkyumPjAUQRt3wWFJYgrlV6wdEOiht/I=; b=QRRkhJfYi+SD5N2gnL0qDMxV97N76RaXiOZP5vBVQRhhBl52qQST9LwQSFlaodnRSmOnqe 3xa+H9bPzh4LA5BQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 0D6D713BA9; Tue, 30 Nov 2021 06:49:55 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id u30XApPJpWEWVQAAMHmgww (envelope-from ); Tue, 30 Nov 2021 06:49:55 +0000 Subject: Re: [PATCH v2 3/3] blk-crypto: show crypto capabilities in sysfs To: Eric Biggers , linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-scsi@vger.kernel.org, linux-mmc@vger.kernel.org, Greg Kroah-Hartman , Bart Van Assche References: <20211130040306.148925-1-ebiggers@kernel.org> <20211130040306.148925-4-ebiggers@kernel.org> From: Hannes Reinecke Message-ID: <8745aed7-d4b6-eb8d-60ad-f4d768d62a62@suse.de> Date: Tue, 30 Nov 2021 07:49:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20211130040306.148925-4-ebiggers@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 11/30/21 5:03 AM, Eric Biggers wrote: > From: Eric Biggers > > Add sysfs files that expose the inline encryption capabilities of > request queues: > > /sys/class/block/$disk/queue/crypto/max_dun_bits > /sys/class/block/$disk/queue/crypto/modes/$mode > /sys/class/block/$disk/queue/crypto/num_keyslots > > Userspace can use these new files to decide what encryption settings to > use, or whether to use inline encryption at all. This also brings the > crypto capabilities in line with the other queue properties, which are > already discoverable via the queue directory in sysfs. > > Design notes: > > - Place the new files in a new subdirectory "crypto" to group them > together and to avoid complicating the main "queue" directory. This > also makes it possible to replace "crypto" with a symlink later if > we ever make the blk_crypto_profiles into real kobjects (see below). > > - It was necessary to define a new kobject that corresponds to the > crypto subdirectory. For now, this kobject just contains a pointer > to the blk_crypto_profile. Note that multiple queues (and hence > multiple such kobjects) may refer to the same blk_crypto_profile. > > An alternative design would more closely match the current kernel > data structures: the blk_crypto_profile could be a kobject itself, > located directly under the host controller device's kobject, while > /sys/class/block/$disk/queue/crypto would be a symlink to it. > > I decided not to do that for now because it would require a lot more > changes, such as no longer embedding blk_crypto_profile in other > structures, and also because I'm not sure we can rule out moving the > crypto capabilities into 'struct queue_limits' in the future. (Even > if multiple queues share the same crypto engine, maybe the supported > data unit sizes could differ due to other queue properties.) It > would also still be possible to switch to that design later without > breaking userspace, by replacing the directory with a symlink. > > - Use "max_dun_bits" instead of "max_dun_bytes". Currently, the > kernel internally stores this value in bytes, but that's an > implementation detail. It probably makes more sense to talk about > this value in bits, and choosing bits is more future-proof. > > - "modes" is a sub-subdirectory, since there may be multiple supported > crypto modes, and sysfs is supposed to have one value per file. > Why do you have a sub-directory here? From what I can see, that subdirectory just contains the supported modes, so wouldn't it be easier to create individual files like 'mode_' instead of a subdirectory? Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer