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=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 35F34C43461 for ; Wed, 9 Sep 2020 01:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F18232177B for ; Wed, 9 Sep 2020 01:16:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RVy/UXe2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728297AbgIIBQ6 (ORCPT ); Tue, 8 Sep 2020 21:16:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:29305 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726369AbgIIBQ6 (ORCPT ); Tue, 8 Sep 2020 21:16:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599614216; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=i8mv0FVtNHbd9zXlKvA6wXb9TbJe9plomVS4MYmguXw=; b=RVy/UXe2pYU2s4SAn31uycS9U6xJziZYIdIIc6iFrOm81cd9oHQfDnk67HOpwJm5sPqo0u UPJLLE6ALRt74nUQPrfJZKb0lKA2jvxlI787HaQ6L1sP0sd/Sm8C4TIlg3HatXgb1vQrhQ ftAo18QIaojHNo0f7YKT0oARm+mtEWY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-464-UZ-XJF2-NnWRoDA0VNN-ug-1; Tue, 08 Sep 2020 21:16:54 -0400 X-MC-Unique: UZ-XJF2-NnWRoDA0VNN-ug-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27300100558D; Wed, 9 Sep 2020 01:16:53 +0000 (UTC) Received: from T590 (ovpn-12-76.pek2.redhat.com [10.72.12.76]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 122673A40; Wed, 9 Sep 2020 01:16:45 +0000 (UTC) Date: Wed, 9 Sep 2020 09:16:41 +0800 From: Ming Lei To: Bart Van Assche Cc: Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , Keith Busch , Johannes Thumshirn , Sagi Grimberg , Chao Leng Subject: Re: [PATCH V3 1/4] blk-mq: serialize queue quiesce and unquiesce by mutex Message-ID: <20200909011641.GA1465199@T590> References: <20200908081538.1434936-1-ming.lei@redhat.com> <20200908081538.1434936-2-ming.lei@redhat.com> <8e040e37-d1df-ea5f-8a63-f4067d092b72@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8e040e37-d1df-ea5f-8a63-f4067d092b72@acm.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Sep 08, 2020 at 10:54:14AM -0700, Bart Van Assche wrote: > On 2020-09-08 01:15, Ming Lei wrote: > > void blk_mq_unquiesce_queue(struct request_queue *q) > > { > > + mutex_lock(&q->mq_quiesce_lock); > > + > > blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); > > > > /* dispatch requests which are inserted during quiescing */ > > blk_mq_run_hw_queues(q, true); > > + > > + mutex_unlock(&q->mq_quiesce_lock); > > } > Has the sunvdc driver been retested? It calls blk_mq_unquiesce_queue() > with a spinlock held. As you know calling mutex_lock() while holding a > spinlock is not allowed. I am wondering if sunvdc is still being actively used, the similar lock issue has been existed since 7996a8b5511a ("blk-mq: fix hang caused by freeze/unfreeze sequence") which is committed in May 2019. + spin_lock_irq(&port->vio.lock); + port->drain = 0; + blk_mq_unquiesce_queue(q); + blk_mq_unfreeze_queue(q); mutex_lock is added to blk_mq_unfreeze_queue(q) since commit 7996a8b5511a. Not see such report actually. > There may be other drivers than the sunvdc driver that do this. Most calls of blk_mq_unquiesce_queue are easily to be audited because blk_mq_quiesce_queue is used in same callsite. I will take a close look at this thing before posting next version. Thanks, Ming