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_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 63697C11F69 for ; Tue, 29 Jun 2021 08:22:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CDE261DD6 for ; Tue, 29 Jun 2021 08:22:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232731AbhF2IZM (ORCPT ); Tue, 29 Jun 2021 04:25:12 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3328 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232644AbhF2IYz (ORCPT ); Tue, 29 Jun 2021 04:24:55 -0400 Received: from fraeml744-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GDcdd4jBLz6GBS1; Tue, 29 Jun 2021 16:12:05 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml744-chm.china.huawei.com (10.206.15.225) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 29 Jun 2021 10:22:26 +0200 Received: from [10.47.83.88] (10.47.83.88) 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 15.1.2176.2; Tue, 29 Jun 2021 09:22:26 +0100 Subject: Re: [PATCH] scsi: Delete scsi_{get,free}_host_dev() To: Hannes Reinecke , , CC: , , , , References: <1624640314-93055-1-git-send-email-john.garry@huawei.com> <044a31ed-f6e9-3017-4973-3a02765933e0@suse.de> From: John Garry Message-ID: <77afd764-4195-188d-ef0e-c4adcfa38f8b@huawei.com> Date: Tue, 29 Jun 2021 09:15:37 +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: <044a31ed-f6e9-3017-4973-3a02765933e0@suse.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.83.88] X-ClientProxiedBy: lhreml751-chm.china.huawei.com (10.201.108.201) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/06/2021 12:55, Hannes Reinecke wrote: > On 6/25/21 6:58 PM, John Garry wrote: >> Functions scsi_{get,free}_host_dev() no longer have any in-tree users, so >> delete them. >> >> Signed-off-by: John Garry >> --- >> An alt agenda of this patch is to get clarification on whether this API >> should be used for Hannes' reserved commands series. >> >> Originally the recommendation was to use it, but now it seems to be to >> not use it: >> https://lore.kernel.org/linux-scsi/55918d68-7385-0153-0bd9-d822d3ce4c21@suse.de/ >> >> > Please don't. ok, we can take that as a nacked-by for now. > > Before we're doing something like this I would like to have > clarification from Christoph which way he prefers for reserved commands. > Personally I _do_ like the host dev approach for reserved commands as it > allows us to re-use existing infrastructure. So when you deleted the gdth driver, the request there was to delete this API. And in the v8 series, again, the request was not to use it, and use the dedicated request queue instead - I do know that this conflicts with the much earlier suggestion not to do that, but that was when gdth existed. As for reuse of existing infrastructure, using this API seems to add more code than it reuses. So don't we just need to add a dedicated request_queue for host? I don't know the use in having the scsi_device. Having said all that, we don't seem to have a host request_queue sysfs entry with either solution, which would be good. > > Christoph? > Thanks, John