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 X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 459B2C48BC2 for ; Wed, 23 Jun 2021 12:03:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F6EA61002 for ; Wed, 23 Jun 2021 12:03:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230292AbhFWMFs (ORCPT ); Wed, 23 Jun 2021 08:05:48 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:38264 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230019AbhFWMFq (ORCPT ); Wed, 23 Jun 2021 08:05:46 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 081741FD65; Wed, 23 Jun 2021 12:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1624449808; 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=pTV0UJMvjAlHC0068bqJsxAfZBAJ3v623+Gud9Q+2ok=; b=JEwVwd5lWr59EcR28oxtQoQeflZEtZ6GtvIqFr+3qPap9DIqlIxS16dhKGeD88AdgHhrQK FnaGZl6LUbHmCXqawqEN/CTgAdCZYjbNY2Zq58VJ569soEXfRxCLgg/SnorvXx7d8ZtdW5 YHjUElLq6Fyl98xM/jRHIF7FsABnP5E= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624449808; 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=pTV0UJMvjAlHC0068bqJsxAfZBAJ3v623+Gud9Q+2ok=; b=NwoYa3wurxv0LfPJNjQb5ZEd1tVjfIl9pupg76GLbPUHgiC4wWiYX5RAAVvfb5RlyXPytc j4Nna4Tidn/PA9Aw== Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id ADCA511A97; Wed, 23 Jun 2021 12:03:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1624449807; 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=pTV0UJMvjAlHC0068bqJsxAfZBAJ3v623+Gud9Q+2ok=; b=YF5l59Liz2PwKX7sWBCPjDz8AJ/4dt0uGGV+1XjZDof0eMiBagemhhka4asURm2hQLjPHk pToA+nVJaTwvciMnCOeiYAJllplYa7V3i+WBOd2tbr8Zr07nHtB757209mun/fOjmXwXHB FA7WEn/722VuFam8SwPykndZg7ENp4I= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624449807; 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=pTV0UJMvjAlHC0068bqJsxAfZBAJ3v623+Gud9Q+2ok=; b=phFHobecXngr10YyZGcNi33kkMtxHjkkaAk14F16/Y1M+JRLYUrn+0tW9Bj8hI1yrs1KWX xRKybiw+NIuYoXBA== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id rhDpKA8j02B6DwAALh3uQQ (envelope-from ); Wed, 23 Jun 2021 12:03:27 +0000 Subject: Re: [PATCH v3 0/6] block: add a sequence number to disks To: Matteo Croce , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe Cc: linux-kernel@vger.kernel.org, Lennart Poettering , Luca Boccassi , Alexander Viro , Damien Le Moal , Tejun Heo , =?UTF-8?Q?Javier_Gonz=c3=a1lez?= , Niklas Cassel , Johannes Thumshirn , Matthew Wilcox , Christoph Hellwig , JeffleXu References: <20210623105858.6978-1-mcroce@linux.microsoft.com> From: Hannes Reinecke Message-ID: Date: Wed, 23 Jun 2021 14:03:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210623105858.6978-1-mcroce@linux.microsoft.com> 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-kernel@vger.kernel.org On 6/23/21 12:58 PM, Matteo Croce wrote: > From: Matteo Croce > > With this series a monotonically increasing number is added to disks, > precisely in the genhd struct, and it's exported in sysfs and uevent. > > This helps the userspace correlate events for devices that reuse the > same device, like loop. > I'm failing to see the point here. Apparently you are assuming that there is a userspace tool tracking events, and has a need to correlate events related to different instances of the disk. But if you have an userspace application tracking events, why can't the same application track the 'add' and 'remove' events to track the lifetime of the devices, and implement its own numbering based on that? Why do we need to burden the kernel with this? 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