Event Channel notification issue - Gntdev device

[Akshay Jaggi]

Hi,

I've been working on unmap notifications for the grant table user space
device (check progress: https://reviews.freebsd.org/D7293).

I've added and tested unmap_clear_byte notification and unmap_send_event
notification is left.

I was implementing the unmap_send_notify on event-channel, but I am stuck.
Basically, linux grabs a reference to the event-channel port, in case it is
deallocated, so that it can still send a notify. I could not find such a
reference-grabbing mechanism for event channel in FreeBSD. What should I do
now?
Should I add notify, adding the constraint that you cannot deallocate your
reference to that port till the notify is sent (ie, after an unmap).

Regards,
Akshay