Messages in this thread Patch in this message | | | Date | Wed, 05 Jan 2022 10:15:36 +0000 | From | Paul Cercueil <> | Subject | Re: [PATCH 3/8] PM: core: Add EXPORT[_GPL]_SIMPLE_DEV_PM_OPS macros |
| |
Hi Jonathan,
Le mer., janv. 5 2022 at 10:03:32 +0000, Jonathan Cameron <Jonathan.Cameron@Huawei.com> a écrit : > On Tue, 4 Jan 2022 21:42:09 +0000 > Paul Cercueil <paul@crapouillou.net> wrote: > >> These macros are defined conditionally, according to CONFIG_PM: >> - if CONFIG_PM is enabled, these macros resolve to >> DEFINE_SIMPLE_DEV_PM_OPS(), and the dev_pm_ops symbol will be >> exported. >> >> - if CONFIG_PM is disabled, these macros will result in a dummy >> static >> dev_pm_ops to be created with the __maybe_unused flag. The >> dev_pm_ops >> will then be discarded by the compiler, along with the provided >> callback functions if they are not used anywhere else. >> >> In the second case, the symbol is not exported, which should be >> perfectly fine - users of the symbol should all use the pm_ptr() or >> pm_sleep_ptr() macro, so the dev_pm_ops marked as "extern" in the >> client's code will never be accessed. >> >> Signed-off-by: Paul Cercueil <paul@crapouillou.net> >> --- >> include/linux/pm.h | 33 ++++++++++++++++++++++++++++++--- >> 1 file changed, 30 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/pm.h b/include/linux/pm.h >> index 389e600df233..a1ce29566aea 100644 >> --- a/include/linux/pm.h >> +++ b/include/linux/pm.h >> @@ -8,6 +8,7 @@ >> #ifndef _LINUX_PM_H >> #define _LINUX_PM_H >> >> +#include <linux/export.h> >> #include <linux/list.h> >> #include <linux/workqueue.h> >> #include <linux/spinlock.h> >> @@ -357,14 +358,40 @@ struct dev_pm_ops { >> #define SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) >> #endif >> >> +#define _DEFINE_DEV_PM_OPS(name, \ >> + suspend_fn, resume_fn, \ >> + runtime_suspend_fn, runtime_resume_fn, idle_fn) \ >> +const struct dev_pm_ops name = { \ >> + SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ >> + RUNTIME_PM_OPS(runtime_suspend_fn, runtime_resume_fn, idle_fn) \ >> +} >> + > > one blank line probably enough. > >> + >> /* >> * Use this if you want to use the same suspend and resume >> callbacks for suspend >> * to RAM and hibernation. >> */ >> #define DEFINE_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >> -const struct dev_pm_ops name = { \ >> - SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ >> -} >> + _DEFINE_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL) >> + >> +#ifdef CONFIG_PM >> +#define _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, >> runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn, sec) \ >> + _DEFINE_DEV_PM_OPS(name, suspend_fn, resume_fn, >> runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn); \ >> + _EXPORT_SYMBOL(name, sec) >> +#else >> +#define _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, >> runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn, sec) \ >> +static __maybe_unused _DEFINE_DEV_PM_OPS(__static_##name, >> suspend_fn, \ >> + resume_fn, runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn) >> +#endif >> + >> +#define EXPORT_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >> + _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL, >> "") >> +#define EXPORT_GPL_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >> + _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL, >> "_gpl") > > So you can get away with these two cases because the > SYSTEM_SLEEP_PM_OPS() all have > pm_sleep_ptr() wrappers. However, _EXPORT_DEV_PM_OPS() could be used > directly and > would require __maybe_unused for the RUNTIME_PM_OPS() parameters > which isn't ideal.
I don't see why. On both cases (CONFIG_PM enabled/disabled) the runtime-PM callbacks are referenced directly, so at no point do they appear as unused; therefore __maybe_unused is not needed.
Cheers, -Paul
> Maybe I'm missing some reason that isn't a problem though as easy to > get lost in > these macros. :) > > You could argue that the _ is meant to indicate that macro shouldn't > be used directly > but I'm not that optimistic. > > Jonathan > > > >> >> /* Deprecated. Use DEFINE_SIMPLE_DEV_PM_OPS() instead. */ >> #define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >
| |