On Thu, Feb 22, 2024 at 11:47 AM Daniel Lezcano
<daniel.lezcano@xxxxxxxxxx> wrote:
>
> On 14/02/2024 13:45, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > The current code requires thermal zone creators to pass pointers to
> > writable ops structures to thermal_zone_device_register_with_trips()
> > which needs to modify the target struct thermal_zone_device_ops object
> > if the "critical" operation in it is NULL.
> >
> > Moreover, the callers of thermal_zone_device_register_with_trips() are
> > required to hold on to the struct thermal_zone_device_ops object passed
> > to it until the given thermal zone is unregistered.
> >
> > Both of these requirements are quite inconvenient, so modify struct
> > thermal_zone_device to contain struct thermal_zone_device_ops as field and
> > make thermal_zone_device_register_with_trips() copy the contents of the
> > struct thermal_zone_device_ops passed to it via a pointer (which can be
> > const now) to that field.
> >
> > Also adjust the code using thermal zone ops accordingly and modify
> > thermal_of_zone_register() to use a local ops variable during
> > thermal zone registration so ops do not need to be freed in
> > thermal_of_zone_unregister() any more.
>
> [ ... ]
>
> > static void thermal_of_zone_unregister(struct thermal_zone_device *tz)
> > {
> > struct thermal_trip *trips = tz->trips;
> > - struct thermal_zone_device_ops *ops = tz->ops;
> >
> > thermal_zone_device_disable(tz);
> > thermal_zone_device_unregister(tz);
> > kfree(trips);
>
> Not related to the current patch but with patch 1/6. Freeing the trip
> points here will lead to a double free given it is already freed from
> thermal_zone_device_unregister() after the changes introduces in patch
> 1, right ?
No, patch [1/6] doesn't free the caller-supplied ops, just copies them
into the local instance. Attempting to free a static ops would not be
a good idea, for example.
BTW, thanks for all of the reviews, but this series is not applicable
without the one at
https://lore.kernel.org/linux-pm/6017196.lOV4Wx5bFT@kreacher/
