Messages in this thread | | | Subject | Re: [PATCH v7 04/15] s390/vfio-ap: implement in-use callback for vfio_ap driver | From | Tony Krowiak <> | Date | Thu, 16 Apr 2020 10:45:20 -0400 |
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On 4/16/20 7:18 AM, Cornelia Huck wrote: > On Tue, 7 Apr 2020 15:20:04 -0400 > Tony Krowiak <akrowiak@linux.ibm.com> wrote: > >> Let's implement the callback to indicate when an APQN >> is in use by the vfio_ap device driver. The callback is >> invoked whenever a change to the apmask or aqmask would >> result in one or more queue devices being removed from the driver. The >> vfio_ap device driver will indicate a resource is in use >> if the APQN of any of the queue devices to be removed are assigned to >> any of the matrix mdevs under the driver's control. >> >> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> >> --- >> drivers/s390/crypto/vfio_ap_drv.c | 1 + >> drivers/s390/crypto/vfio_ap_ops.c | 47 +++++++++++++++++---------- >> drivers/s390/crypto/vfio_ap_private.h | 2 ++ >> 3 files changed, 33 insertions(+), 17 deletions(-) >> @@ -1369,3 +1371,14 @@ void vfio_ap_mdev_remove_queue(struct ap_queue *queue) >> kfree(q); >> mutex_unlock(&matrix_dev->lock); >> } >> + >> +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) ? true : false; > Maybe > > in_use = !!vfio_ap_mdev_verify_no_sharing(NULL, apm, aqm); > > ?
To be honest, I find the !! expression very confusing. Every time I see it, I have to spend time thinking about what the result of !! is going to be. I think the statement should be left as-is because it more clearly expresses the intent.
> >> + mutex_unlock(&matrix_dev->lock); >> + >> + return in_use; >> +}
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