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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 0C5D6C004E4 for ; Wed, 13 Jun 2018 12:17:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5DDF20020 for ; Wed, 13 Jun 2018 12:17:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5DDF20020 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935495AbeFMMRG (ORCPT ); Wed, 13 Jun 2018 08:17:06 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:57236 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935273AbeFMMRF (ORCPT ); Wed, 13 Jun 2018 08:17:05 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5DCFSqV084355 for ; Wed, 13 Jun 2018 08:17:05 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jk0b6fp47-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 13 Jun 2018 08:17:04 -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) Wed, 13 Jun 2018 13:16:58 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w5DCGupc31916142 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 13 Jun 2018 12:16:57 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 12EBEAE053; Wed, 13 Jun 2018 13:05:47 +0100 (BST) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 38E2AAE045; Wed, 13 Jun 2018 13:05:46 +0100 (BST) Received: from [9.152.224.92] (unknown [9.152.224.92]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 13 Jun 2018 13:05:46 +0100 (BST) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v5 04/13] s390: vfio-ap: base implementation of VFIO AP device driver To: Cornelia Huck Cc: Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com References: <1525705912-12815-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1525705912-12815-5-git-send-email-akrowiak@linux.vnet.ibm.com> <889b8d41-e08c-0eb5-2de0-a1d6669a03b3@linux.ibm.com> <20180613094812.1fd1846d.cohuck@redhat.com> <41e7ccbd-f6f5-ba20-f236-7824c682994d@linux.ibm.com> <20180613131402.0305d092.cohuck@redhat.com> <7237751c-66b5-d14c-5b71-cc1cfc79db87@linux.ibm.com> <20180613141221.5b924348.cohuck@redhat.com> From: Pierre Morel Date: Wed, 13 Jun 2018 14:16:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180613141221.5b924348.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18061312-0028-0000-0000-000002D066FD X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18061312-0029-0000-0000-0000238788AF Message-Id: <65ec9340-6a25-20ac-3078-f67992d5cc15@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-13_05:,, 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806130136 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/06/2018 14:12, Cornelia Huck wrote: > On Wed, 13 Jun 2018 14:01:54 +0200 > Pierre Morel wrote: > >> On 13/06/2018 13:14, Cornelia Huck wrote: >>> On Wed, 13 Jun 2018 12:54:40 +0200 >>> Pierre Morel wrote: >>> >>>> On 13/06/2018 09:48, Cornelia Huck wrote: >>>>> On Wed, 13 Jun 2018 09:41:16 +0200 >>>>> Pierre Morel wrote: >>>>> >>>>>> On 07/05/2018 17:11, Tony Krowiak wrote: >>>>>>> Introduces a new AP device driver. This device driver >>>>>>> is built on the VFIO mediated device framework. The framework >>>>>>> provides sysfs interfaces that facilitate passthrough >>>>>>> access by guests to devices installed on the linux host. >>>>>> ...snip... >>>>>> >>>>>>> +static int vfio_ap_matrix_dev_create(void) >>>>>>> +{ >>>>>>> + int ret; >>>>>>> + >>>>>>> + vfio_ap_root_device = root_device_register(VFIO_AP_ROOT_NAME); >>>>>>> + >>>>>>> + if (IS_ERR(vfio_ap_root_device)) { >>>>>>> + ret = PTR_ERR(vfio_ap_root_device); >>>>>>> + goto done; >>>>>>> + } >>>>>>> + >>>>>>> + ap_matrix = kzalloc(sizeof(*ap_matrix), GFP_KERNEL); >>>>>>> + if (!ap_matrix) { >>>>>>> + ret = -ENOMEM; >>>>>>> + goto matrix_alloc_err; >>>>>>> + } >>>>>>> + >>>>>>> + ap_matrix->device.type = &vfio_ap_dev_type; >>>>>>> + dev_set_name(&ap_matrix->device, "%s", VFIO_AP_DEV_NAME); >>>>>>> + ap_matrix->device.parent = vfio_ap_root_device; >>>>>>> + ap_matrix->device.release = vfio_ap_matrix_dev_release; >>>>>>> + ap_matrix->device.driver = &vfio_ap_drv.driver; >>>>>>> + >>>>>>> + ret = device_register(&ap_matrix->device); >>>>>>> + if (ret) >>>>>>> + goto matrix_reg_err; >>>>>>> + >>>>>>> + goto done; >>>>>>> + >>>>>>> +matrix_reg_err: >>>>>>> + put_device(&ap_matrix->device); >>>>>> Did not see this before but here you certainly want to >>>>>> do a kfree and not a put_device. >>>>> No, this must not be a kfree. Once you've tried to register something >>>>> embedding a struct device with the driver core, you need to use >>>>> put_device, as another path may have acquired a reference, even if >>>>> registering ultimately failed. See the comment for device_register(). >>>>> IOW, the code is correct. >>>> learned something again :) , >>>> but still, a kfree is needed for the kzalloc. >>>> Does'nt it? >>> No, the put callback for the embedding structure needs to take care of >>> freeing things. Otherwise it is buggy. >> Seems buggy to me. >> How does the put_device knows if it is embedded and then in what it is >> embedded ? > It does not need to know; the code registering the structure needs to > set up device->release correctly. yes right, thanks. > >>> >>>>> >>>>>> >>>>>>> + >>>>>>> +matrix_alloc_err: >>>>>>> + root_device_unregister(vfio_ap_root_device); >>>>>>> + >>>>>>> +done: >>>>>>> + return ret; >>>>>>> +} >>>>>>> + >>>>>>> +static void vfio_ap_matrix_dev_destroy(struct ap_matrix *ap_matrix) >>>>>>> +{ >>>>>>> + device_unregister(&ap_matrix->device); >>>>>>> + root_device_unregister(vfio_ap_root_device); >>>>>> Also here you need a kfree(ap_matrix) too . >>>>> Same here. >>>>> >> -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany