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=-4.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 21C57C43441 for ; Mon, 19 Nov 2018 10:06:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D802820870 for ; Mon, 19 Nov 2018 10:06:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="lbyJUAoh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D802820870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S1727641AbeKSU3R (ORCPT ); Mon, 19 Nov 2018 15:29:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:35816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726287AbeKSU3R (ORCPT ); Mon, 19 Nov 2018 15:29:17 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0728120831; Mon, 19 Nov 2018 10:06:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542621968; bh=cZeSgYi1n9rqBNie/SFcmdBqLrz9po+z4D6FT7GfABg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lbyJUAoh3uWU7KRM2hLTmk1im9kWNt24+QwP1ocvj0mGr2rCI6Iomjix/sx+CXxD+ leLzO/OOP8KwLPM6jqrS1oH1t3tMFlUZijiSPwe6MLZlenQL2ALisWFZZb9E4hXBLf 6uypg2VPW/hbcpSe8x6NyzAG/9mpxgHSmLXfHbvo= Date: Mon, 19 Nov 2018 11:06:06 +0100 From: Greg Kroah-Hartman To: Ming Lei 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: <20181119100606.GB19910@kroah.com> References: <20181116112311.4117-1-ming.lei@redhat.com> <20181116112311.4117-2-ming.lei@redhat.com> <20181116140521.GB4595@kroah.com> <20181117022637.GB8872@ming.t460p> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181117022637.GB8872@ming.t460p> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Sat, Nov 17, 2018 at 10:26:38AM +0800, Ming Lei wrote: > 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/$DEV/mq are covered by this kobject > actually, and all are for exposing blk-mq specific information, but now there is > only blk-mq, and legacy io path is removed. I am sorry, but I really can not parse this sentance at all. What Documentation/ABI/ entries are covered by this kobject, that should help me out more. And what do you mean by "legacy io"? > That is why I mentioned we may remove this kobject last time and move all under > /sys/block/$DEV/queue, however you thought that may break some userspace. Who relies on these sysfs files today? > If we want to backport them to stable, this patch may be a bit easier to go. Why do you want to backport any of this to stable? thanks, greg k-h