[LinuxPPS] [PATCH 02/11] Streamline interrupt handling; get rid of a lock and idr_find()

[George Spelvin]

Rodolfo Giometti <giometti at enneenne.com> wrote:
> LinuxPPS's pps_register_source(), pps_unregister_source() and
> pps_event() have different features due PPS nature, that is
> pps_event() __can_be_called_while_the_others_execute__.

*Sigh*.  I don't think it's at all difficult to arrange that pps_event
has completed before pps_unregister_source is done, but doing it
your way...

Okay, is there *any* guaranteed bound as to when pps_event will no longer
be called?

It doesn't have to be in seconds, just "when X happens, you know that
the final caller of pps_event on that device has returned."

Or can I never unload the module for fear that pps_event will be called?

And if I don't want events delivered to the wrong PPS device
(not its fault; it just happened to be allocated the same device
number as the buggy one), I can never re-use device IDs?

(I'm trying to work through the old PPS code.  The whole serial code
base is a bit intricate.)