From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v5 2/7] s390: ap: new vfio_ap_queue structure Date: Fri, 15 Mar 2019 14:29:18 +0100 Message-ID: <97431ae5-8a96-2512-870b-0a463e9ec768@linux.ibm.com> References: <1552493104-30510-1-git-send-email-pmorel@linux.ibm.com> <1552493104-30510-3-git-send-email-pmorel@linux.ibm.com> <20190315113330.5ef0eeef.cohuck@redhat.com> Reply-To: pmorel@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190315113330.5ef0eeef.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck Cc: borntraeger@de.ibm.com, alex.williamson@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, akrowiak@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 List-ID: On 15/03/2019 11:33, Cornelia Huck wrote: > On Wed, 13 Mar 2019 17:04:59 +0100 > Pierre Morel wrote: > >> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c >> index e9824c3..df6f21a 100644 >> --- a/drivers/s390/crypto/vfio_ap_drv.c >> +++ b/drivers/s390/crypto/vfio_ap_drv.c >> @@ -40,14 +40,42 @@ static struct ap_device_id ap_queue_ids[] = { >> >> MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); >> >> +/** >> + * vfio_ap_queue_dev_probe: >> + * >> + * Allocate a vfio_ap_queue structure and associate it >> + * with the device as driver_data. >> + */ >> static int vfio_ap_queue_dev_probe(struct ap_device *apdev) >> { >> + struct vfio_ap_queue *q; >> + >> + q = kzalloc(sizeof(*q), GFP_KERNEL); >> + if (!q) >> + return -ENOMEM; >> + dev_set_drvdata(&apdev->device, q); >> + q->apqn = to_ap_queue(&apdev->device)->qid; >> + INIT_LIST_HEAD(&q->list); >> + mutex_lock(&matrix_dev->lock); >> + list_add(&q->list, &matrix_dev->free_list); >> + mutex_unlock(&matrix_dev->lock); > > From what I can see, dealing with the free_list is supposed to be > protected by the matrix_dev mutex, and at a glance, it indeed seems to > be held every time you interact with the list. I think it would be good > to document that with a comment. Yes. It is a big lock but only on administrative tasks so I think it is harmless. > > (I have not reviewed this deeply, and I won't be able to look at this > more until April, sorry.) OK. Thanks for the comments. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany