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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 0535BC43381 for ; Mon, 25 Mar 2019 07:37:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C50902087E for ; Mon, 25 Mar 2019 07:37:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="0koYTBda" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729885AbfCYHhg (ORCPT ); Mon, 25 Mar 2019 03:37:36 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:39478 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729720AbfCYHhf (ORCPT ); Mon, 25 Mar 2019 03:37:35 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x2P7Y2ol101899; Mon, 25 Mar 2019 07:37:12 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=2VlQBHb5HwLShox7N890bgyUAQsYFewwS6A/Xh3YKjk=; b=0koYTBdahgG8L+HkuugwPUluQjoLt0aFjAM5h1EnoaZP9abJND3f9QCtv+2ft3u4ISLF 3q4s1ttzknR+h2BSdFW733ro/g66YzFfNRM6HaDcYeq23jud8Cwn4p+oXLSSsd1tnNmW fjn0U14M8PHpYxSom2mzktmicJGEZ9wgKVCJwttxB5/RssP0iXUyuPkgrTSs3WCX+8CC n8G2J48RDDLE9w8/2PYzwK7/SEKer/yItAjQg3ekPcWeJ627KpIaz3zqPa0Vy6sq1l8E iKXr9tDBlsJfoZs0JyzoSTot3+bjqRmilLLFnPsC+KyVIGf/7WxLjAJjsFqMk6JBE4X+ gw== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2120.oracle.com with ESMTP id 2re6dj2aky-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 25 Mar 2019 07:37:11 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x2P7b6Da000665 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 25 Mar 2019 07:37:06 GMT Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x2P7b5iw027258; Mon, 25 Mar 2019 07:37:05 GMT Received: from [10.182.71.8] (/10.182.71.8) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 25 Mar 2019 00:37:05 -0700 Subject: Re: [PATCH V2 8/8] blk-mq: remove blk_mq_tagset_busy_iter To: Hannes Reinecke , axboe@kernel.dk Cc: linux-block@vger.kernel.org, jsmart2021@gmail.com, sagi@grimberg.me, josef@toxicpanda.com, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, keith.busch@intel.com, jthumshirn@suse.de, hch@lst.de, bvanassche@acm.org References: <1553492318-1810-1-git-send-email-jianchao.w.wang@oracle.com> <1553492318-1810-9-git-send-email-jianchao.w.wang@oracle.com> <47fe0e2a-f427-0e3e-e15b-a9e2bffb502f@suse.de> From: "jianchao.wang" Message-ID: Date: Mon, 25 Mar 2019 15:37:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <47fe0e2a-f427-0e3e-e15b-a9e2bffb502f@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9205 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=950 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903250057 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Hannes On 3/25/19 3:18 PM, Hannes Reinecke wrote: > On 3/25/19 6:38 AM, Jianchao Wang wrote: >> As nobody uses blk_mq_tagset_busy_iter, remove it. >> >> Signed-off-by: Jianchao Wang >> --- >>   block/blk-mq-tag.c     | 95 -------------------------------------------------- >>   include/linux/blk-mq.h |  2 -- >>   2 files changed, 97 deletions(-) >> > Please, don't. > > I'm currently implementing reserved commands for SCSI and reworking the SCSI error handling where I rely on this interface quite heavily. blk_mq_tagset_busy_iter could access some stale requests which maybe freed due to io scheduler switching, request_queue cleanup (shared tagset) when there is someone submits io and gets driver tag. When io scheduler attached, even quiesce request_queue won't work. If this patchset is accepted, blk_mq_tagset_busy_iter could be replaced with blk_mq_queue_inflight_tag_iter which needs to be invoked by every request_queue that shares the tagset. Please go ahead your work. Thanks Jianchao > > Cheers, > > Hannes