On 4/23/20 11:13 PM, Halil Pasic wrote:
On Thu, 16 Apr 2020 10:45:20 -0400
Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote:
On 4/16/20 7:18 AM, Cornelia Huck wrote:
On Tue, 7 Apr 2020 15:20:04 -0400
Tony Krowiak <akrowiak@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
---
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.
This is discussion is just about cosmetics, I believe. Just a piece of
advice: try to be sensitive about the community. In this community, and
I believe in C general !! is the idiomatic way to convert number to
boolean. Why would one want to do that is a bit longer story. The short
version is in logic condition context the value 0 is false and any
other value is true. !! keeps false value (0) false, and forces a true to
the most true true value. If you keep getting confused every time you
run across a !! that won't help with reading other peoples C.
Regards,
Halil
The point is moot. After seeing that Conny's comment generated a
discussion, I decided to avoid wasting additional time discussing
personal preferences and am now using the !! syntax. Unfortunately,
I've been having some odd problems with my email client and my
response to Pierre's comment never made it to the list, so I apologize
that you had to waste valuable time on your tutorial.
+ mutex_unlock(&matrix_dev->lock);
+
+ return in_use;
+}
