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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 8C3ECC43613 for ; Fri, 21 Jun 2019 13:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68FF8216B7 for ; Fri, 21 Jun 2019 13:37:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726264AbfFUNhu (ORCPT ); Fri, 21 Jun 2019 09:37:50 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:63690 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726010AbfFUNhs (ORCPT ); Fri, 21 Jun 2019 09:37:48 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5LDba19099061 for ; Fri, 21 Jun 2019 09:37:47 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2t8y882wrv-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 21 Jun 2019 09:37:44 -0400 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 21 Jun 2019 14:37:14 +0100 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5LDb4W738994388 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 21 Jun 2019 13:37:04 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B628DA405C; Fri, 21 Jun 2019 13:37:12 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 592A7A4054; Fri, 21 Jun 2019 13:37:12 +0000 (GMT) Received: from oc2783563651 (unknown [9.152.224.137]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 21 Jun 2019 13:37:12 +0000 (GMT) Date: Fri, 21 Jun 2019 15:37:11 +0200 From: Halil Pasic To: Cornelia Huck Cc: Sebastian Ott , Peter Oberparleiter , Alex Williamson , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] s390/cio: introduce driver_override on the css bus In-Reply-To: <20190621115604.0f3e3f69.cohuck@redhat.com> References: <20190613110815.17251-1-cohuck@redhat.com> <20190621115604.0f3e3f69.cohuck@redhat.com> Organization: IBM X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19062113-0012-0000-0000-0000032B3A4B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19062113-0013-0000-0000-000021646468 Message-Id: <20190621153711.7d713c4d.pasic@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-21_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=894 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906210114 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 21 Jun 2019 11:56:04 +0200 Cornelia Huck wrote: > On Thu, 13 Jun 2019 13:08:15 +0200 > Cornelia Huck wrote: > > > Sometimes, we want to control which of the matching drivers > > binds to a subchannel device (e.g. for subchannels we want to > > handle via vfio-ccw). > > > > For pci devices, a mechanism to do so has been introduced in > > 782a985d7af2 ("PCI: Introduce new device binding path using > > pci_dev.driver_override"). It makes sense to introduce the > > driver_override attribute for subchannel devices as well, so > > that we can easily extend the 'driverctl' tool (which makes > > use of the driver_override attribute for pci). > > > > Note that unlike pci we still require a driver override to > > match the subchannel type; matching more than one subchannel > > type is probably not useful anyway. > > > > Signed-off-by: Cornelia Huck Reviewed-by: Halil Pasic I guess the '\n' handling is customary, and is what the same what the pci counterpart (782a985d7af2) does anyway. It bothers me a little that you don't necessarily get back from with show what you stored. E.g. # echo -e "bug\nfree" > /sys/bus/css/devices/0.0.0001/driver_override # echo $? 0 # cat /sys/bus/css/devices/0.0.0001/driver_override bug # echo $? 0 But given the previous art (782a985d7af2) I think it is the best way to do it. The rest is very straightforward. > > --- > > > > Lightly tested; did not yet attempt to adapt driverctl to actually > > make use of it. > > Friendly ping. > > In the meanwhile, I figured out that you do not need to adapt driverctl > at all, but just need to pass it '-b css' to work on the css bus; this > seems to work just fine with this patch applied. > Interesting. I hope to get around and have a closer look at it eventually. Regards, Halil