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 6DC1CCE7A81 for ; Mon, 25 Sep 2023 15:02:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232482AbjIYPCY (ORCPT ); Mon, 25 Sep 2023 11:02:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229647AbjIYPCW (ORCPT ); Mon, 25 Sep 2023 11:02:22 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C48EB101; Mon, 25 Sep 2023 08:02:15 -0700 (PDT) Received: from kwepemm000012.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4RvQym20rJzrSxy; Mon, 25 Sep 2023 23:00:00 +0800 (CST) Received: from [10.174.178.220] (10.174.178.220) by kwepemm000012.china.huawei.com (7.193.23.142) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Mon, 25 Sep 2023 23:02:13 +0800 Message-ID: <6531a3b0-915d-8078-b265-95231405ac4d@huawei.com> Date: Mon, 25 Sep 2023 23:02:12 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH 1/2] scsi: core: scsi_device_online() return false if state is SDEV_CANCEL Content-Language: en-US To: "James E . J . Bottomley" , "Martin K . Petersen" , CC: , References: <20230922093636.2645961-1-haowenchao2@huawei.com> <20230922093636.2645961-2-haowenchao2@huawei.com> From: Wenchao Hao In-Reply-To: <20230922093636.2645961-2-haowenchao2@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.220] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm000012.china.huawei.com (7.193.23.142) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/9/22 17:36, Wenchao Hao wrote: > SDEV_CANCEL is set when removing device and scsi_device_online() should > return false if sdev_state is SDEV_CANCEL. > > IO hang would be caused if return true when state is SDEV_CANCEL with > following order: > > T1: T2:scsi_error_handler > __scsi_remove_device() > scsi_device_set_state(sdev, SDEV_CANCEL) > scsi_eh_flush_done_q() > if (scsi_device_online(sdev)) > scsi_queue_insert(scmd,...) > > The command added by scsi_queue_insert() would never be handled any > more. > > Signed-off-by: Wenchao Hao > --- > include/scsi/scsi_device.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index 75b2235b99e2..c498a12f7715 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -517,7 +517,8 @@ static inline int scsi_device_online(struct scsi_device *sdev) > { > return (sdev->sdev_state != SDEV_OFFLINE && > sdev->sdev_state != SDEV_TRANSPORT_OFFLINE && > - sdev->sdev_state != SDEV_DEL); > + sdev->sdev_state != SDEV_DEL && > + sdev->sdev_state != SDEV_CANCEL); > } > static inline int scsi_device_blocked(struct scsi_device *sdev) > { Return false when if sdev_state is SDEV_CANCEL seems change some flow in error handle, but I don't know if we should introduce these changes. I think it's both ok to finish the failed command or try more recovery steps. For example, in scsi_eh_bus_device_reset(), when scsi_try_bus_device_reset() returned SUCCEED but the sdev_state is SDEV_CANCEL, should skip TUR and just call scsi_eh_finish_cmd() to add this LUN's error command to done_q? We can address the issue of IO hang described in this patch by running scsi_device's queue regardless of the scsi_device's state and it seems a better solution because the main reason of IO hang is as following: scsi_restart_operations() -> scsi_run_host_queues() -> shost_for_each_device() // skip scsi_device with SDEV_DEL // or SDEV_CANCEL state