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 99064C4338F for ; Mon, 9 Aug 2021 01:11:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78F4E60C40 for ; Mon, 9 Aug 2021 01:11:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232113AbhHIBLc (ORCPT ); Sun, 8 Aug 2021 21:11:32 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:13298 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229891AbhHIBL2 (ORCPT ); Sun, 8 Aug 2021 21:11:28 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4GjdFH25Hwz84D3; Mon, 9 Aug 2021 09:06:11 +0800 (CST) Received: from dggema762-chm.china.huawei.com (10.1.198.204) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Mon, 9 Aug 2021 09:11:07 +0800 Received: from [10.174.176.73] (10.174.176.73) by dggema762-chm.china.huawei.com (10.1.198.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Mon, 9 Aug 2021 09:11:05 +0800 Subject: Re: [PATCH 1/2] blk-mq: add two interfaces to lock/unlock blk_mq_tags->lock To: Bart Van Assche , , , CC: , , , References: <20210808031752.579882-1-yukuai3@huawei.com> <20210808031752.579882-2-yukuai3@huawei.com> <1e6b1a1e-eb45-f6c7-a8ce-e534b8cda710@acm.org> From: "yukuai (C)" Message-ID: <115d97bf-8c7f-44e5-7665-9f7f2c8c3c2b@huawei.com> Date: Mon, 9 Aug 2021 09:11:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <1e6b1a1e-eb45-f6c7-a8ce-e534b8cda710@acm.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.73] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggema762-chm.china.huawei.com (10.1.198.204) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/08/09 0:44, Bart Van Assche wrote: > On 8/7/21 8:17 PM, Yu Kuai wrote: >> +void blk_mq_tags_lock(struct blk_mq_tags *tags, unsigned long *flags) >> +{ >> + spin_lock_irqsave(&tags->lock, *flags); >> +} >> +EXPORT_SYMBOL(blk_mq_tags_lock); >> + >> +void blk_mq_tags_unlock(struct blk_mq_tags *tags, unsigned long *flags) >> +{ >> + spin_unlock_irqrestore(&tags->lock, *flags); >> +} >> +EXPORT_SYMBOL(blk_mq_tags_unlock); > > The tag map lock is an implementation detail and hence this lock must > not be used directly by block drivers. I propose to introduce and export > a new function to block drivers that does the following: > * Lock tags->lock. > * Call blk_mq_tag_to_rq(). > * Check whether the request is in the started state. If so, increment > its reference count. > * Unlock tags->lock. Hi, Bart Thanks for your advice, will do this in next iteration. Best regards Kuai