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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 21CB4C43381 for ; Tue, 19 Mar 2019 15:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E569D2133D for ; Tue, 19 Mar 2019 15:24:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553009081; bh=UcSGivjR4IoEW8F4+KWyh6OXtmk+nNpGljJV2aQJv64=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=MXEYJxXr3WXBOUyIa5eE/N4pxXh19FKbLbVwMoYhqfPrrun24s+bkbrKRhi9fq50Y 1Y/iN9pbqUdKN3MTOhWce2UjoI1P1vVg8M5Ces+iTQzx3RTNNF50YRrR+4RRDdCJTI jzUwZH/+ATERJs1lUVpgVRvbAFn2jhWPZJ8QpTZo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727417AbfCSPYk (ORCPT ); Tue, 19 Mar 2019 11:24:40 -0400 Received: from mga01.intel.com ([192.55.52.88]:45109 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726579AbfCSPYk (ORCPT ); Tue, 19 Mar 2019 11:24:40 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Mar 2019 08:24:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,498,1544515200"; d="scan'208";a="135598379" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga007.fm.intel.com with ESMTP; 19 Mar 2019 08:24:38 -0700 Date: Tue, 19 Mar 2019 09:25:34 -0600 From: Keith Busch To: Bart Van Assche Cc: "jianchao.wang" , axboe@kernel.dk, 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, hare@suse.de, jthumshirn@suse.de, hch@lst.de Subject: Re: [PATCH 0/8]: blk-mq: use static_rqs to iterate busy tags Message-ID: <20190319152533.GD24176@localhost.localdomain> References: <1552640264-26101-1-git-send-email-jianchao.w.wang@oracle.com> <1552930085.152266.36.camel@acm.org> <3cd58454-eda3-de9a-0eed-b6a7edbce28f@oracle.com> <1553008222.152266.43.camel@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1553008222.152266.43.camel@acm.org> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Mar 19, 2019 at 08:10:22AM -0700, Bart Van Assche wrote: > On Tue, 2019-03-19 at 09:25 +0800, jianchao.wang wrote: > > Do you mean this patch from Jens ? > > https://marc.info/?l=linux-block&m=154534605914798&w=2 > > > > + rcu_read_lock(); > > sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data); > > + rcu_read_unlock(); > > > > The busy_iter_fn could sleep for nvme > > blk_mq_check_expired > > -> blk_mq_rq_timed_out > > -> q->mq_ops->timeout > > nvme_timeout > > -> nvme_dev_disable > > -> mutex_lock dev->shutdown_lock > > Hi Jianchao, > > I think that's an additional reason to rewrite NVMe error handling ... Nonesense. Block timeout handling runs in a work queue precicesly so handlers can actually do useful work in line with the notification.