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 92164E80ABF for ; Thu, 28 Sep 2023 01:39:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229831AbjI1BjE (ORCPT ); Wed, 27 Sep 2023 21:39:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229437AbjI1BjC (ORCPT ); Wed, 27 Sep 2023 21:39:02 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 783BBAC; Wed, 27 Sep 2023 18:38:59 -0700 (PDT) Received: from kwepemm000012.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Rwx0S45CdzrStx; Thu, 28 Sep 2023 09:36:40 +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; Thu, 28 Sep 2023 09:38:56 +0800 Message-ID: <382fe161-95fb-3249-32cf-07058f81a4bc@huawei.com> Date: Thu, 28 Sep 2023 09:38:55 +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 v5 01/10] scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem Content-Language: en-US To: , "James E . J . Bottomley" , "Martin K . Petersen" , , CC: , References: <20230922092906.2645265-1-haowenchao2@huawei.com> <20230922092906.2645265-2-haowenchao2@huawei.com> <8c7cfe09-d145-4387-91cf-da9d4e2398e1@interlog.com> From: Wenchao Hao In-Reply-To: <8c7cfe09-d145-4387-91cf-da9d4e2398e1@interlog.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit 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 2023/9/28 9:13, Douglas Gilbert wrote: > On 2023-09-22 05:28, Wenchao Hao wrote: >> Create directory scsi_debug in the root of the debugfs filesystem. >> Prepare to add interface for manage error injection. >> >> Acked-by: Douglas Gilbert >> Signed-off-by: Wenchao Hao >> --- >>   drivers/scsi/scsi_debug.c | 6 ++++++ >>   1 file changed, 6 insertions(+) >> >> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c >> index 9c0af50501f9..35c336271b13 100644 >> --- a/drivers/scsi/scsi_debug.c >> +++ b/drivers/scsi/scsi_debug.c >> @@ -41,6 +41,7 @@ >>   #include >>   #include >>   #include >> +#include >>   #include >> @@ -862,6 +863,8 @@ static const int device_qfull_result = >>   static const int condition_met_result = SAM_STAT_CONDITION_MET; >> +static struct dentry *sdebug_debugfs_root; >> + >>   /* Only do the extra work involved in logical block provisioning if one or >>    * more of the lbpu, lbpws or lbpws10 parameters are given and we are doing >> @@ -7011,6 +7014,8 @@ static int __init scsi_debug_init(void) >>           goto driver_unreg; >>       } >> +    sdebug_debugfs_root = debugfs_create_dir("scsi_debug", NULL); > > debugfs_create_dir() can fail and return NULL. Looking at other drivers, most > seem to assume it will work. Since the scsi_debug driver is often used to test > abnormal situations, perhaps adding something like: >     if (!sdebug_debugfs_root) >         pr_info("%s: failed to create initial debugfs directory\n", __func__); > > might save someone a bit of time if a NULL dereference on sdebug_debugfs_root > follows later. That is what the mpt3sas driver does. > Yes, I would fix it by checking return value of debugfs related call after your review suggestions for other patches. > Doug Gilbert > >> + >>       for (k = 0; k < hosts_to_add; k++) { >>           if (want_store && k == 0) { >>               ret = sdebug_add_host_helper(idx); >> @@ -7057,6 +7062,7 @@ static void __exit scsi_debug_exit(void) >>       sdebug_erase_all_stores(false); >>       xa_destroy(per_store_ap); >> +    debugfs_remove(sdebug_debugfs_root); >>   } >>   device_initcall(scsi_debug_init); > >