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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 19A02C43381 for ; Fri, 15 Feb 2019 22:13:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DAE04222D7 for ; Fri, 15 Feb 2019 22:13:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732250AbfBOWNb (ORCPT ); Fri, 15 Feb 2019 17:13:31 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:46796 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728617AbfBOWNb (ORCPT ); Fri, 15 Feb 2019 17:13:31 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1FM8Zla073211 for ; Fri, 15 Feb 2019 17:13:30 -0500 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qp1rd1sym-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 15 Feb 2019 17:13:30 -0500 Received: from localhost by e11.ny.us.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, 15 Feb 2019 22:13:26 -0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1FMDMjr21299222 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 15 Feb 2019 22:13:22 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BD800AC0A5; Fri, 15 Feb 2019 22:13:22 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 14812AC0A2; Fri, 15 Feb 2019 22:13:22 +0000 (GMT) Received: from [9.80.239.175] (unknown [9.80.239.175]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 15 Feb 2019 22:13:21 +0000 (GMT) Subject: Re: [PATCH v3 4/9] s390: ap: tools to find a queue with a specific APQN To: Pierre Morel , borntraeger@de.ibm.com Cc: 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, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com References: <1550152269-6317-1-git-send-email-pmorel@linux.ibm.com> <1550152269-6317-5-git-send-email-pmorel@linux.ibm.com> From: Tony Krowiak Date: Fri, 15 Feb 2019 17:13:21 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1550152269-6317-5-git-send-email-pmorel@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19021522-2213-0000-0000-00000351E385 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010604; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000280; SDB=6.01161592; UDB=6.00606356; IPR=6.00942152; MB=3.00025604; MTD=3.00000008; XFM=3.00000015; UTC=2019-02-15 22:13:28 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19021522-2214-0000-0000-00005D5E765F Message-Id: <56f583e7-fb41-ec54-ccf9-585a3e51b1c4@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-15_16:,, 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=8.0.1-1810050000 definitions=main-1902150144 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/14/19 8:51 AM, Pierre Morel wrote: > We need to find the queue with a specific APQN during the > handling of the interception of the PQAP/AQIC instruction. > > To handle the AP associated device reference count we keep > track of it in the vfio_ap_queue until we put the device. > > Signed-off-by: Pierre Morel > --- > drivers/s390/crypto/vfio_ap_ops.c | 54 +++++++++++++++++++++++++++++++++++ > drivers/s390/crypto/vfio_ap_private.h | 1 + > 2 files changed, 55 insertions(+) > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index 900b9cf..2a52c9b 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -24,6 +24,60 @@ > #define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough" > #define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device" > > +/** > + * vfio_ap_check_apqn: check if a ap_queue is of a given APQN > + * > + * Returns 1 if we have a match. > + * Otherwise returns 0. > + */ > +static int vfio_ap_check_apqn(struct device *dev, void *data) > +{ > + struct vfio_ap_queue *q = dev_get_drvdata(dev); > + > + return (q->apqn == *(int *)data); > +} > + > +/** > + * vfio_ap_get_queue: Retrieve a queue with a specific APQN > + * @apqn: The queue APQN > + * > + * Retrieve a queue with a specific APQN from the list of the > + * devices associated to the vfio_ap_driver. > + * > + * The vfio_ap_queue has been already associated with the device > + * during the probe. > + * Store the associated device for reference counting > + * > + * Returns the pointer to the associated vfio_ap_queue > + */ > +static __attribute__((unused)) > + struct vfio_ap_queue *vfio_ap_get_queue(int apqn) I think you should change this signature for the reasons I stated below: struct device *vfio_ap_get_queue_dev(int apqn) > +{ > + struct device *dev; > + struct vfio_ap_queue *q; > + > + dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL, &apqn, > + vfio_ap_check_apqn); > + if (!dev) > + return NULL; > + q = dev_get_drvdata(dev); > + q->dev = dev; Why store the device with the vfio_ap_queue object? Why not just return the device. The caller can get the vfio_ap_queue from the device's driver data. It seems the only reason for the 'dev' field is to temporarily hold a ref to the device so it can be put later. Why not just put the device. > + return q; > +} > + > +/** > + * vfio_ap_put_queue: lower device reference count for a queue > + * @q: The queue > + * > + * put the associated device > + * > + */ > +static __attribute__((unused)) void vfio_ap_put_queue(struct vfio_ap_queue *q) > +{ > + put_device(q->dev); > + q->dev = NULL; > +} I would get rid of this function. If you take my suggestion above, you can just call the put_device() directly. There will be no need for this superfluous 'dev' field. > + > static void vfio_ap_matrix_init(struct ap_config_info *info, > struct ap_matrix *matrix) > { > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h > index 8836f01..081f0d7 100644 > --- a/drivers/s390/crypto/vfio_ap_private.h > +++ b/drivers/s390/crypto/vfio_ap_private.h > @@ -87,6 +87,7 @@ extern int vfio_ap_mdev_register(void); > extern void vfio_ap_mdev_unregister(void); > > struct vfio_ap_queue { > + struct device *dev; No need for this as per my comments above. > int apqn; > }; > #endif /* _VFIO_AP_PRIVATE_H_ */ >