Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 20 Jan 2023 15:13:25 +0100 | Subject | Re: [PATCH 3/5] thermal/core: Remove unneeded mutex_destroy() |
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On Fri, Jan 20, 2023 at 3:10 PM Zhang, Rui <rui.zhang@intel.com> wrote: > > On Thu, 2023-01-19 at 18:21 +0100, Rafael J. Wysocki wrote: > > On Thursday, January 19, 2023 5:39:29 PM CET Daniel Lezcano wrote: > > > On 19/01/2023 16:05, Rafael J. Wysocki wrote: > > > > On Thu, Jan 19, 2023 at 3:13 PM Daniel Lezcano > > > > <daniel.lezcano@linaro.org> wrote: > > > > > On 19/01/2023 14:24, Rafael J. Wysocki wrote: > > > > > > On Thu, Jan 19, 2023 at 1:48 PM Daniel Lezcano > > > > > > <daniel.lezcano@linaro.org> wrote: > > > > > > > On 19/01/2023 13:11, Rafael J. Wysocki wrote: > > > > > > > > On Thu, Jan 19, 2023 at 10:30 AM Daniel Lezcano > > > > > > > > <daniel.lezcano@linaro.org> wrote: > > > > > > > > > On 19/01/2023 08:41, Zhang, Rui wrote: > > > > > > > > > > On Wed, 2023-01-18 at 22:11 +0100, Daniel Lezcano > > > > > > > > > > wrote: > > > > > > > > > > > If the thermal framework fails to initialize, the > > > > > > > > > > > mutex can be used > > > > > > > > > > > by > > > > > > > > > > > the different functions registering a thermal zone > > > > > > > > > > > anyway. > > > > > > > > > > > > > > > > > > > > Hmm, even with no governors and unregistered thermal > > > > > > > > > > sysfs class? > > > > > > > > > > > > > > > > > > > > IMO, thermal APIs for registering a > > > > > > > > > > thermal_zone/cooling_device should > > > > > > > > > > yield early if thermal_init fails. > > > > > > > > > > For other APIs that relies on a valid > > > > > > > > > > thermal_zone_device/thermal_cooling_device pointer, > > > > > > > > > > nothing needs to > > > > > > > > > > be changed. > > > > > > > > > > > > > > > > > > > > what do you think? > > > > > > > > > > > > > > > > > > I think you are right. > > > > > > > > > > > > > > > > > > It would be nice if we can check if the thermal class > > > > > > > > > is registered and > > > > > > > > > bail out if not. But there is no function to check that > > > > > > > > > AFAICS. > > > > > > > > > > > > > > > > > > Alternatively we can convert the thermal class static > > > > > > > > > structure to a > > > > > > > > > pointer and set it to NULL in case of error in > > > > > > > > > thermal_init() ? > > > > > > > > > > > > > > > > It doesn't matter if this is a NULL pointer or a static > > > > > > > > object that's > > > > > > > > clearly marked as unused. > > > > > > > > > > > > > > Without introducing another global variable, is it possible > > > > > > > to know if > > > > > > > the class is used or not ? > > > > > > > > > > > > If thermal_class.p is cleared to NULL on class_register() > > > > > > failures in > > > > > > thermal_init() (unfortunately, the driver core doesn't do > > > > > > that, but > > > > > > maybe it should - let me cut a patch for that), then it can > > > > > > be used > > > > > > for that. > > > > > > > > > > It should be in class_unregister() too, right ? > > > > > > > > > > And is it possible to add a class_is_registered() ? in order to > > > > > prevent > > > > > accessing class structure internals ? > > > > > > > > I suppose so. > > > > > > > > And we'd like it to be used some places like > > > > thermal_zone_device_register_with_trips(), wouldn't we? > > > > > > Yes, in thermal_zone_device_register_with_trips() and > > > thermal_cooling_device_register(). > > > > Something like the patch below I think, because > > thermal_cooling_device_register() > > is a wrapper around thermal_zone_device_register_with_trips(). > > > > thermal_zone_device_register() is a wrapper around > thermal_zone_device_register_with_trips(), but > thermal_cooling_device_register() is not. :) > > thermal_cooling_device_register() registers a cooling device to thermal > class so the class_is_registered() check is still needed.
OK, thanks!
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