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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5EF5C43334 for ; Fri, 22 Jul 2022 02:59:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231338AbiGVC7E (ORCPT ); Thu, 21 Jul 2022 22:59:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229997AbiGVC7E (ORCPT ); Thu, 21 Jul 2022 22:59:04 -0400 Received: from out30-54.freemail.mail.aliyun.com (out30-54.freemail.mail.aliyun.com [115.124.30.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 381D59965A for ; Thu, 21 Jul 2022 19:59:03 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046049;MF=ziyangzhang@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0VK3N472_1658458739; Received: from 30.97.56.196(mailfrom:ZiyangZhang@linux.alibaba.com fp:SMTPD_---0VK3N472_1658458739) by smtp.aliyun-inc.com; Fri, 22 Jul 2022 10:59:00 +0800 Message-ID: <5bb0cf22-fee8-e5fd-8f8b-93c866e522f0@linux.alibaba.com> Date: Fri, 22 Jul 2022 10:58:59 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH 1/2] ublk_drv: move destroying device out of ublk_add_dev Content-Language: en-US To: Ming Lei Cc: linux-block@vger.kernel.org, Jens Axboe References: <20220722023638.601667-1-ming.lei@redhat.com> <20220722023638.601667-2-ming.lei@redhat.com> From: Ziyang Zhang In-Reply-To: <20220722023638.601667-2-ming.lei@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2022/7/22 10:36, Ming Lei wrote: > ublk_device is allocated in ublk_ctrl_add_dev(), so code will become more > readable by just letting ublk_ctrl_add_dev() destroy ublk_device in case > of ublk_add_dev() failure. > > Meantime ub->mutex is destroyed in __ublk_destroy_dev(), but it may > not be initialized when ublk_add_dev() fails, so fix it by moving > mutex_init(ub->mutex) before any failure path. > > Signed-off-by: Ming Lei > --- > drivers/block/ublk_drv.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index f058f40b639c..d03563286c76 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -1106,9 +1106,10 @@ static int ublk_add_dev(struct ublk_device *ub) > > INIT_WORK(&ub->stop_work, ublk_stop_work_fn); > INIT_DELAYED_WORK(&ub->monitor_work, ublk_daemon_monitor_work); > + mutex_init(&ub->mutex); > > if (ublk_init_queues(ub)) > - goto out_destroy_dev; > + return err; > > ub->tag_set.ops = &ublk_mq_ops; > ub->tag_set.nr_hw_queues = ub->dev_info.nr_hw_queues; > @@ -1122,7 +1123,6 @@ static int ublk_add_dev(struct ublk_device *ub) > goto out_deinit_queues; > > ublk_align_max_io_size(ub); > - mutex_init(&ub->mutex); > spin_lock_init(&ub->mm_lock); > > /* add char dev so that ublksrv daemon can be setup */ > @@ -1130,8 +1130,6 @@ static int ublk_add_dev(struct ublk_device *ub) > > out_deinit_queues: > ublk_deinit_queues(ub); > -out_destroy_dev: > - __ublk_destroy_dev(ub); > return err; > } > > @@ -1331,8 +1329,10 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd) > ub->dev_info.dev_id = ub->ub_number; > > ret = ublk_add_dev(ub); > - if (ret) > + if (ret) { > + __ublk_destroy_dev(ub); > goto out_unlock; > + } Hi, Ming. Now, if ublk_add_dev() returns failure, __ublk_destroy_dev() is called anyway. However, in current ublk_drv:ublk_add_dev(): ... return ublk_add_chdev(ub); <---- here out_deinit_queues: ublk_deinit_queues(ub); out_destroy_dev: __ublk_destroy_dev(ub); return err; ublk_add_chdev() returns and the returned value(maybe a failure) directly pass to ublk_ctrl_add_dev which does NOT call __ublk_destroy_dev() please check it is correct to call __ublk_destroy_dev() if ublk_add_chdev() fails. > > if (copy_to_user(argp, &ub->dev_info, sizeof(info))) { > ublk_remove(ub);