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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 7096DC433B4 for ; Fri, 16 Apr 2021 08:19:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53AB561184 for ; Fri, 16 Apr 2021 08:19:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235120AbhDPIUN (ORCPT ); Fri, 16 Apr 2021 04:20:13 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:2869 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229706AbhDPIUM (ORCPT ); Fri, 16 Apr 2021 04:20:12 -0400 Received: from fraeml702-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4FM8BT6V6Qz68BBZ; Fri, 16 Apr 2021 16:14:25 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml702-chm.china.huawei.com (10.206.15.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2106.2; Fri, 16 Apr 2021 10:19:45 +0200 Received: from [10.47.83.179] (10.47.83.179) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Fri, 16 Apr 2021 09:19:44 +0100 Subject: Re: [PATCH] scsi_debug: fix cmd_per_lun, set to max_queue To: Ming Lei CC: Douglas Gilbert , , , , , References: <20210415015031.607153-1-dgilbert@interlog.com> <580349dc-0152-8f39-5f3c-be9115e3bf12@huawei.com> From: John Garry Message-ID: Date: Fri, 16 Apr 2021 09:17:09 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.83.179] X-ClientProxiedBy: lhreml727-chm.china.huawei.com (10.201.108.78) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 16/04/2021 02:46, Ming Lei wrote: >> int display_failure_msg = 1, ret; >> struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); >> + int depth; >> >> sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size, >> GFP_KERNEL); >> @@ -276,8 +277,13 @@ static struct scsi_device *scsi_alloc_sdev(struct >> scsi_target *starget, >> WARN_ON_ONCE(!blk_get_queue(sdev->request_queue)); >> sdev->request_queue->queuedata = sdev; >> >> - scsi_change_queue_depth(sdev, sdev->host->cmd_per_lun ? >> - sdev->host->cmd_per_lun : 1); >> + if (sdev->host->cmd_per_lun) >> + depth = min_t(int, sdev->host->cmd_per_lun, >> + sdev->host->can_queue); >> + else >> + depth = 1; >> + >> + scsi_change_queue_depth(sdev, depth); > 'cmd_per_lun' should have been set as correct from the beginning instead > of capping it for changing queue depth: > > diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c > index 697c09ef259b..0d9954eabbb8 100644 > --- a/drivers/scsi/hosts.c > +++ b/drivers/scsi/hosts.c > @@ -414,7 +414,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) > shost->can_queue = sht->can_queue; > shost->sg_tablesize = sht->sg_tablesize; > shost->sg_prot_tablesize = sht->sg_prot_tablesize; > - shost->cmd_per_lun = sht->cmd_per_lun; > + shost->cmd_per_lun = min_t(int, sht->cmd_per_lun, shost->can_queue); > shost->no_write_same = sht->no_write_same; > shost->host_tagset = sht->host_tagset; My concern here is that it is a common pattern in LLDDs to overwrite the initial shost member values between scsi_host_alloc() and scsi_add_host(). Thanks, John