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SubjectRe: [PATCH v2 3/6] PM: core: Add EXPORT[_GPL]_SIMPLE_DEV_PM_OPS macros


Le ven., janv. 7 2022 at 17:33:04 +0100, Ulf Hansson
<ulf.hansson@linaro.org> a écrit :
> On Wed, 5 Jan 2022 at 19:30, 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.
>
> How common is it to export the dev_pm_ops? Do we really need a macro
> for this?

$ rgrep EXPORT_SYMBOL drivers/ |grep pm_ops |wc -l
44

That should be enough to justify a macro.

Cheers,
-Paul

>
> The similar comment/question applies for patch5.
>
>>
>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> Kind regards
> Uffe
>
>> ---
>>
>> Notes:
>> v2: Remove useless empty line
>>
>> include/linux/pm.h | 32 +++++++++++++++++++++++++++++---
>> 1 file changed, 29 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/linux/pm.h b/include/linux/pm.h
>> index 389e600df233..b82f40e701ab 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 +358,39 @@ 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) \
>> +}
>> +
>> /*
>> * 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")
>>
>> /* Deprecated. Use DEFINE_SIMPLE_DEV_PM_OPS() instead. */
>> #define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
>> --
>> 2.34.1
>>


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