From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:2278 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391816AbhASLsY (ORCPT ); Tue, 19 Jan 2021 06:48:24 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 10JBXdxa105555 for ; Tue, 19 Jan 2021 06:47:39 -0500 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 365xfg8r2q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 19 Jan 2021 06:47:39 -0500 Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 10JBbHi3133010 for ; Tue, 19 Jan 2021 06:47:38 -0500 Date: Tue, 19 Jan 2021 12:47:24 +0100 From: Halil Pasic Subject: Re: [RFC 1/1] s390/cio: Remove uevent-suppress from css driver Message-ID: <20210119124724.4c5cec19.pasic@linux.ibm.com> In-Reply-To: References: <20201124093407.23189-1-vneethv@linux.ibm.com> <20201124093407.23189-2-vneethv@linux.ibm.com> <20201124140220.77c65539.cohuck@redhat.com> <4be7e163-1118-d365-7d25-df39ba78181f@linux.vnet.ibm.com> <0b4e34b7-7a4e-71b0-8a64-ea909e64f416@linux.ibm.com> <20201208183054.44f4fc2d.cohuck@redhat.com> <20201209135203.0008ab18.pasic@linux.ibm.com> <20201215191307.281c6e6f.cohuck@redhat.com> <20201219073316.1be609d5.pasic@linux.ibm.com> <20201221164634.11cd3813.cohuck@redhat.com> <20201221175117.2c5f5fcb.pasic@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit List-ID: To: Boris Fiuczynski Cc: Cornelia Huck , Vineeth Vijayan , Vineeth Vijayan , oberpar@linux.ibm.com, linux-s390@vger.kernel.org, farman@linux.ibm.com On Thu, 14 Jan 2021 14:03:25 +0100 Boris Fiuczynski wrote: > On 12/21/20 5:51 PM, Halil Pasic wrote: > > On Mon, 21 Dec 2020 16:46:34 +0100 > > Cornelia Huck wrote: > > > >> On Sat, 19 Dec 2020 07:33:16 +0100 > >> Halil Pasic wrote: > >> > >>> I finally came around to test this. In my experience driverctl works for > >>> subchannels and vfio_ccw without this patch, and continues to work with > >>> it. I found the code in driverctl that does the unbind and the implicit > >>> bind (via drivers_probe after after driver_override was set). > >>> > >>> So now I have to ask, how exactly was the original problem diagnosed? > >>> > >>> In https://marc.info/?l=linux-s390&m=158591045732735&w=2 there is a > >>> paragraph like: > >>> > >>> """ > >>> So while there's definitely a good reason for wanting to delay uevents, > >>> it is also introducing problems. One is udev rules for subchannels that > >>> are supposed to do something before a driver binds (e.g. setting > >>> driver_override to bind an I/O subchannel to vfio_ccw instead of > >>> io_subchannel) are not effective, as the ADD uevent will only be > >>> generated when the io_subchannel driver is already done with doing all > >>> setup. Another one is that only the ADD uevent is generated after > >>> uevent suppression is lifted; any other uevents that might have been > >>> generated are lost. > >>> """ > >>> > >>> This is not how driverclt works! I.e. it deals with the situation that > >>> the I/O subchannel was already bound to the io_subchannel driver at > >>> the time the udev rule installed by driverctl activates (via the > >>> mechanism I described above). > >> > >> That's... weird. It definitely did not work on the LPAR I initially > >> tried it out on! > >> > > > > I think Boris told me some weeks ago that it didn't work for him either. > > I will check with him after the winter sleep. > > Yesterday I used driverctl successfully for a subchannel on F33. > > Not sure what went wrong a couple of months ago but I cannot reproduce > driverctl not working now. Thanks Boris! @Conny: IMHO driver_override has to work without this patch. Can you figure out, why did you claim it does not (and provide instructions on how to reproduce the problem)? > > > > >> However, I think removing the suppression still looks like a good idea: > >> we still have the "any uevent other than ADD will have been lost" > >> problem. > >> > I totally agree with this. @Vineeth: I think the best way to move forward is to respin this patch with a commit message, that doesn't argue about driver_override. Regards, Halil [..]