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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 E6152C433DB for ; Tue, 9 Mar 2021 19:22:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A09AB64F6C for ; Tue, 9 Mar 2021 19:22:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231253AbhCITWC (ORCPT ); Tue, 9 Mar 2021 14:22:02 -0500 Received: from mail-pf1-f181.google.com ([209.85.210.181]:37523 "EHLO mail-pf1-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231197AbhCITVo (ORCPT ); Tue, 9 Mar 2021 14:21:44 -0500 Received: by mail-pf1-f181.google.com with SMTP id a188so10115973pfb.4; Tue, 09 Mar 2021 11:21:44 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=6QwANI+6KZrQSKTeDISq1JRNG3B/zrhvXBbmxR3o6Zg=; b=IobDhRVhcOcXLabn5fLaxlNyXQXR3dmwmM4msH0Zuw/Oe7CgaSGmPC3PN0aNTT2LNP lcSWlsldE0JZsfUn2TM94DDaHFadzHdxkKI4FBTtLwe5lklXTrGQAegbM7yMdUwyRzEW 7L4SAFHIsWnUPVgC6gza2qK/9SNIvGUSP5zRQ6vtzT0krB0PV1wscHECVpB9TSJRk7IA Q1xeB+RdpYpHeAsoDonyv0ofu8/SiFgSOEZntwmNuMS+8ODTGgbG2hT6KgAMsom6x+54 s9yS06+Ril8Gmpe0Okneb32kbESUOh1V2AOmPVs6X4IYuIGONTe3AhHX3ucaonjR4tTI qeTQ== X-Gm-Message-State: AOAM5313H0xYdyJjSyCZT3huXKxR7bvCuw7qS2gi61YyOcdum1tfZGuD N0UxJBIKINMqfA6q8IewgHI= X-Google-Smtp-Source: ABdhPJxPgyGzE/+kY/0TUMf+MhJ1p8MzSCywLlQsacQWliUQvS+Gi0wvvJeoqOzGJQ5QFhnLa0D57A== X-Received: by 2002:a65:57cf:: with SMTP id q15mr26535218pgr.380.1615317704126; Tue, 09 Mar 2021 11:21:44 -0800 (PST) Received: from ?IPv6:2601:647:4000:d7:d77c:6d52:1741:c90? ([2601:647:4000:d7:d77c:6d52:1741:c90]) by smtp.gmail.com with ESMTPSA id fv9sm2936527pjb.23.2021.03.09.11.21.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Mar 2021 11:21:43 -0800 (PST) Subject: Re: [RFC PATCH v3 3/3] blk-mq: Lockout tagset iterator when exiting elevator To: John Garry , hare@suse.de, ming.lei@redhat.com, axboe@kernel.dk, hch@lst.de Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, pragalla@codeaurora.org, kashyap.desai@broadcom.com, yuyufen@huawei.com References: <1614957294-188540-1-git-send-email-john.garry@huawei.com> <1614957294-188540-4-git-send-email-john.garry@huawei.com> <48a3cf78-3f6d-c13c-bca2-1f8277817b45@acm.org> <9c9360bf-7ca9-5c8f-c61d-441044f9c78f@huawei.com> <784a3686-cb54-561d-740c-30e0b3f46df8@acm.org> From: Bart Van Assche Message-ID: Date: Tue, 9 Mar 2021 11:21:41 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 3/9/21 9:47 AM, John Garry wrote: > This does fall over if some tags are allocated without associated > request queue, which I do not know exists. The only tag allocation mechanism I know of is blk_mq_get_tag(). The only blk_mq_get_tag() callers I know of are __blk_mq_alloc_request() and blk_mq_alloc_request_hctx(). So I think all allocated tags are associated with a request queue. Regarding this patch series, I have shared the feedback I wanted to share so I would appreciate it if someone else could also take a look. Thanks, Bart.