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,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, 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 ADA6CC433E0 for ; Tue, 23 Feb 2021 17:52:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BC6864E85 for ; Tue, 23 Feb 2021 17:52:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233796AbhBWRwm (ORCPT ); Tue, 23 Feb 2021 12:52:42 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2599 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232994AbhBWRwl (ORCPT ); Tue, 23 Feb 2021 12:52:41 -0500 Received: from fraeml701-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4DlRNG5vq9z67rB4; Wed, 24 Feb 2021 01:47:58 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml701-chm.china.huawei.com (10.206.15.50) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2106.2; Tue, 23 Feb 2021 18:51:59 +0100 Received: from [10.47.0.222] (10.47.0.222) 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; Tue, 23 Feb 2021 17:51:58 +0000 Subject: Re: [PATCHv7 00/31] scsi: enable reserved commands for LLDDs From: John Garry To: Hannes Reinecke , "Martin K. Petersen" CC: James Bottomley , Christoph Hellwig , , "Viswas.G@microchip.com" References: <20210222132405.91369-1-hare@suse.de> Message-ID: <6d2f5677-b033-9639-82da-655152ad6d8c@huawei.com> Date: Tue, 23 Feb 2021 17:50:11 +0000 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: [10.47.0.222] X-ClientProxiedBy: lhreml742-chm.china.huawei.com (10.201.108.192) 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 23/02/2021 10:16, John Garry wrote: > On 22/02/2021 13:23, Hannes Reinecke wrote: >> Hi all, > > + > >> >> quite some drivers use internal commands for various purposes, most >> commonly sending TMFs or querying the HBA status. >> While these commands use the same submission mechanism than normal >> I/O commands, they will not be counted as outstanding commands, >> requiring those drivers to implement their own mechanism to figure >> out outstanding commands. >> The block layer already has the concept of 'reserved' tags for >> precisely this purpose, namely non-I/O tags which live off a separate >> tag pool. That guarantees that these commands can always be sent, >> and won't be influenced by tag starvation from the I/O tag pool. >> This patchset enables the use of reserved tags for the SCSI midlayer >> by allocating a virtual LUN for the HBA itself which just serves >> as a resource to allocate valid tags from. >> This removes quite some hacks which were required for some >> drivers (eg. fnic or snic), and allows the use of tagset >> iterators within the drivers. >> >> The entire patchset can be found at >> >> git://git.kernel.org/pub/scm/linux/kernel/git/hare/scsi-devel.git >> reserved-tags.v7 > > > Thanks for doing this, I'll have a look. So I got this working eventually for hisi_sas - a few fixes needed: https://github.com/hisilicon/kernel-dev/commits/private-topic-sas-5.11-resv7 I'll have a look at the core patches tomorrow. However, at this point, how about convert just a couple of drivers (the ones which you can test) to get it merged as a start? 31 patches is too many. thanks, John