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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 98B4DC43441 for ; Sat, 17 Nov 2018 02:26:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E67A2087C for ; Sat, 17 Nov 2018 02:26:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E67A2087C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729750AbeKQMlq (ORCPT ); Sat, 17 Nov 2018 07:41:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52200 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729736AbeKQMlq (ORCPT ); Sat, 17 Nov 2018 07:41:46 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1CB78307DA35; Sat, 17 Nov 2018 02:26:51 +0000 (UTC) Received: from ming.t460p (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E16E35126F; Sat, 17 Nov 2018 02:26:43 +0000 (UTC) Date: Sat, 17 Nov 2018 10:26:38 +0800 From: Ming Lei To: Greg Kroah-Hartman Cc: Jens Axboe , linux-block@vger.kernel.org, "jianchao.wang" , Guenter Roeck , stable@vger.kernel.org Subject: Re: [PATCH V2 for-4.21 1/2] blk-mq: not embed .mq_kobj and ctx->kobj into queue instance Message-ID: <20181117022637.GB8872@ming.t460p> References: <20181116112311.4117-1-ming.lei@redhat.com> <20181116112311.4117-2-ming.lei@redhat.com> <20181116140521.GB4595@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181116140521.GB4595@kroah.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Sat, 17 Nov 2018 02:26:51 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Nov 16, 2018 at 06:05:21AM -0800, Greg Kroah-Hartman wrote: > On Fri, Nov 16, 2018 at 07:23:10PM +0800, Ming Lei wrote: > > @@ -456,7 +456,7 @@ struct request_queue { > > /* > > * mq queue kobject > > */ > > - struct kobject mq_kobj; > > + struct kobject *mq_kobj; > > What is this kobject even used for? It wasn't obvious at all from this > patch, why is it needed if you are not using it to reference count the > larger structure here? All attributes and kobjects under /sys/block/$DEV/mq are covered by this kobject actually, and all are for exposing blk-mq specific information, but now there is only blk-mq, and legacy io path is removed. That is why I mentioned we may remove this kobject last time and move all under /sys/block/$DEV/queue, however you thought that may break some userspace. If we want to backport them to stable, this patch may be a bit easier to go. Thanks, Ming