From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v10 05/16] s390/vfio-ap: implement in-use callback for vfio_ap driver References: <20200821195616.13554-1-akrowiak@linux.ibm.com> <20200821195616.13554-6-akrowiak@linux.ibm.com> <20200925112941.71589591.pasic@linux.ibm.com> From: Tony Krowiak Message-ID: Date: Tue, 29 Sep 2020 10:00:01 -0400 MIME-Version: 1.0 In-Reply-To: <20200925112941.71589591.pasic@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US List-ID: To: Halil Pasic Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@linux.ibm.com, borntraeger@de.ibm.com, cohuck@redhat.com, mjrosato@linux.ibm.com, alex.williamson@redhat.com, kwankhede@nvidia.com, fiuczy@linux.ibm.com, frankja@linux.ibm.com, david@redhat.com, imbrenda@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com On 9/25/20 5:29 AM, Halil Pasic wrote: > On Fri, 21 Aug 2020 15:56:05 -0400 > Tony Krowiak wrote: > >> + >> +bool vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm) >> +{ >> + bool in_use; >> + >> + mutex_lock(&matrix_dev->lock); >> + in_use = !!vfio_ap_mdev_verify_no_sharing(NULL, apm, aqm); >> + mutex_unlock(&matrix_dev->lock); > See also my comment for patch 4. AFAIU as soon as you release the lock > the in_use may become outdated in any moment. See my response to your comment for patch 4. > >> + >> + return in_use; >> +}