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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 14157C2BA83 for ; Wed, 12 Feb 2020 16:10:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC3AA20873 for ; Wed, 12 Feb 2020 16:10:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Hh/9JA8c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728630AbgBLQKy (ORCPT ); Wed, 12 Feb 2020 11:10:54 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:33849 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726351AbgBLQKw (ORCPT ); Wed, 12 Feb 2020 11:10:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581523851; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SVVq6qjRCsdQwLjJ3Pl2oKorAivzLQr7S00rXFIKNVM=; b=Hh/9JA8ckC15wtm2NIqgxhL5Dzdqu2WOyQKpRyusIpH+T2NIsD7j8zE/ECnD1GXWUlIWVY 3sKN/bJitoPm2KpyiP/KMCM3fpuwEAFdYduhjnLw23xlTQfT8k81dO04wjoJLtf9edfYyw 4GRZ0IympuO9am3MK8Ks1Ak7ryiU8S0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-166-y1KLSIPVOpe_iMVvs1g-Og-1; Wed, 12 Feb 2020 11:10:47 -0500 X-MC-Unique: y1KLSIPVOpe_iMVvs1g-Og-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7DA7D107ACCC; Wed, 12 Feb 2020 16:10:45 +0000 (UTC) Received: from emilne (unknown [10.18.25.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id C5AF45C100; Wed, 12 Feb 2020 16:10:44 +0000 (UTC) Message-ID: Subject: Re: [PATCH] scsi: Delete scsi_use_blk_mq From: "Ewan D. Milne" To: John Garry , Bart Van Assche , jejb@linux.vnet.ibm.com, martin.petersen@oracle.com Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 12 Feb 2020 11:10:44 -0500 In-Reply-To: <2e2ead7d-503e-3881-b837-7c689a4d44c6@huawei.com> References: <1581355992-139274-1-git-send-email-john.garry@huawei.com> <3795ab1d-5282-458b-6199-91e3def32463@acm.org> <2e2ead7d-503e-3881-b837-7c689a4d44c6@huawei.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2020-02-11 at 11:50 +0000, John Garry wrote: > On 10/02/2020 22:37, Bart Van Assche wrote: > > On 2/10/20 9:33 AM, John Garry wrote: > > > -module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | > > > S_IRUGO); > > Hi Bart, > > > Will this change cause trouble to shell scripts that set or read this > > parameter (/sys/module/scsi_mod/parameters/use_blk_mq)? > > The entry in Documentation/admin-guide/kernel-parameters.txt is gone for > 2 years now. > > And it is not an archaic module param, it was introduced 6 years ago. As > such, I'd say that if a shell script was setup to access this parameter, > then it would prob also pre-check if it exists and gracefully accept > that it may not. > > I will also note that there is still scsi_sysfs.c:show_use_blk_mq(), > which would stay. > > What will the > > impact be on systems where scsi_mod.use_blk_mq=Y is passed by GRUB to > > the kernel at boot time, e.g. because it has been set in the > > GRUB_CMDLINE_LINUX variable in /etc/default/grub? > > The kernel should any params that does not recognize. > > > Having said all that, I don't feel too strongly about deleting this - > it's only some tidy-up. > > Thanks, > John > I think we should remove it. It is not good to have a kernel parameter that people used to be able to set to "N" that no longer does that. -Ewan