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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 18B15C04AA6 for ; Tue, 30 Apr 2019 09:29:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E56B620835 for ; Tue, 30 Apr 2019 09:29:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727126AbfD3J3c (ORCPT ); Tue, 30 Apr 2019 05:29:32 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:43662 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726165AbfD3J3b (ORCPT ); Tue, 30 Apr 2019 05:29:31 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3U9SNjv071612 for ; Tue, 30 Apr 2019 05:29:30 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2s6kf9gt0w-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 30 Apr 2019 05:29:30 -0400 Received: from localhost by e06smtp07.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) Tue, 30 Apr 2019 10:29:25 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3U9TOWF54460628 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Apr 2019 09:29:24 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1A0A64C040; Tue, 30 Apr 2019 09:29:24 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8ABC54C046; Tue, 30 Apr 2019 09:29:23 +0000 (GMT) Received: from oc2783563651 (unknown [9.152.224.116]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 30 Apr 2019 09:29:23 +0000 (GMT) Date: Tue, 30 Apr 2019 11:29:22 +0200 From: Halil Pasic To: Pierre Morel Cc: borntraeger@de.ibm.com, alex.williamson@redhat.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, akrowiak@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com Subject: Re: [PATCH v7 2/4] vfio: ap: register IOMMU VFIO notifier In-Reply-To: References: <1556283688-556-1-git-send-email-pmorel@linux.ibm.com> <1556283688-556-3-git-send-email-pmorel@linux.ibm.com> <20190429180702.641c9110.pasic@linux.ibm.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: 7bit X-TM-AS-GCONF: 00 x-cbid: 19043009-0028-0000-0000-00000368CAF3 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19043009-0029-0000-0000-000024282F4E Message-Id: <20190430112922.0b0b90c5.pasic@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-30_04:,, 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=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=803 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904300063 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 30 Apr 2019 09:59:51 +0200 Pierre Morel wrote: > On 29/04/2019 18:07, Halil Pasic wrote: > > On Fri, 26 Apr 2019 15:01:26 +0200 > > Pierre Morel wrote: > > > >> @@ -858,7 +887,17 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) > >> return ret; > >> } > >> > >> - return 0; > >> + matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier; > >> + events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; > >> + ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, > >> + &events, &matrix_mdev->iommu_notifier); > >> + if (!ret) > >> + return ret; > >> + > >> + vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, > >> + &matrix_mdev->group_notifier); > >> + module_put(THIS_MODULE); > > > > Can you please explain this module_put() here? I don't see anything in > > the cover letter. > > May be you should have a look at the sources or the original patch > series of Tony, there is a try_module_get() at the beginning of open to > make sure that the module is not taken away while in use by the guest. > > In the case we failed to open the mediated device we let fall the reference. > Right, my bad. I did not notice we were on the error recovery path. Regards, Halil