diff mbox series

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

Message ID 20220105182939.106885-4-paul@crapouillou.net (mailing list archive)
State Not Applicable
Headers show
Series DEV_PM_OPS macros rework v2 | expand

Commit Message

Paul Cercueil Jan. 5, 2022, 6:29 p.m. UTC 
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>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---

Notes:
    v2: Remove useless empty line

 include/linux/pm.h | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

Comments

Ulf Hansson Jan. 7, 2022, 4:33 p.m. UTC | #1 
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?

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
>
Paul Cercueil Jan. 7, 2022, 4:43 p.m. UTC | #2 
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
>>
Ulf Hansson Jan. 7, 2022, 5:11 p.m. UTC | #3 
On Fri, 7 Jan 2022 at 17:43, Paul Cercueil <paul@crapouillou.net> wrote:
>
>
>
> 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.

Yep, certainly! I will take a closer look beginning next week.

[...]

Kind regards
Uffe
diff mbox series

Patch

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) \