[2/2] pm: allow drivers to drop #ifdef and __maybe_unused from pm callbacks

Message ID 20210408205858.51751-3-masahiroy@kernel.org
State New
Headers show
Series
  • linux/kconfig.h: move IF_ENABLED() out of <linux/kconfig.h>
Related show

Commit Message

Masahiro Yamada April 8, 2021, 8:58 p.m.
Drivers typically surround suspend and resume callbacks with #ifdef
CONFIG_PM(_SLEEP) or mark them as __maybe_unused in order to avoid
-Wunused-const-variable warnings.

With this commit, drivers will be able to remove #ifdef CONFIG_PM(_SLEEP)
and __maybe_unsed because unused functions are dropped by the compiler
instead of the preprocessor.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 include/linux/pm.h | 67 +++++++++++++++++-----------------------------
 1 file changed, 24 insertions(+), 43 deletions(-)

Comments

Arnd Bergmann April 8, 2021, 9:29 p.m. | #1
On Thu, Apr 8, 2021 at 11:00 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Drivers typically surround suspend and resume callbacks with #ifdef
> CONFIG_PM(_SLEEP) or mark them as __maybe_unused in order to avoid
> -Wunused-const-variable warnings.
>
> With this commit, drivers will be able to remove #ifdef CONFIG_PM(_SLEEP)
> and __maybe_unsed because unused functions are dropped by the compiler
> instead of the preprocessor.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

I tried this before and could not get it to work right.

>
> -#ifdef CONFIG_PM_SLEEP
> +#define pm_ptr(_ptr)           PTR_IF(IS_ENABLED(CONFIG_PM), _ptr)
> +#define pm_sleep_ptr(_ptr)     PTR_IF(IS_ENABLED(CONFIG_PM_SLEEP), _ptr)
> +
>  #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
> -       .suspend = suspend_fn, \
> -       .resume = resume_fn, \
> -       .freeze = suspend_fn, \
> -       .thaw = resume_fn, \
> -       .poweroff = suspend_fn, \
> -       .restore = resume_fn,
> -#else
> -#define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)
> -#endif
> +       .suspend  = pm_sleep_ptr(suspend_fn), \
> +       .resume   = pm_sleep_ptr(resume_fn), \
> +       .freeze   = pm_sleep_ptr(suspend_fn), \
> +       .thaw     = pm_sleep_ptr(resume_fn), \
> +       .poweroff = pm_sleep_ptr(suspend_fn), \
> +       .restore  = pm_sleep_ptr(resume_fn),

The problem that I think you inevitably hit is that you run into a missing
declaration for any driver that still uses an #ifdef around a static
function.

The only way I can see us doing this is to create a new set of
macros that behave like the version you propose here but leave
the old macros in place until the last such #ifdef has been removed.

       Arnd
kernel test robot April 8, 2021, 11:49 p.m. | #2
Hi Masahiro,

I love your patch! Yet something to improve:

[auto build test ERROR on pinctrl/devel]
[also build test ERROR on pm/linux-next soc/for-next linus/master v5.12-rc6]
[cannot apply to next-20210408]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Masahiro-Yamada/linux-kconfig-h-move-IF_ENABLED-out-of-linux-kconfig-h/20210409-050128
base:   https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git devel
config: nds32-randconfig-r004-20210408 (attached as .config)
compiler: nds32le-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/01dfb9e1a54c14b3f491c3a5e93f1e8756042567
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Masahiro-Yamada/linux-kconfig-h-move-IF_ENABLED-out-of-linux-kconfig-h/20210409-050128
        git checkout 01dfb9e1a54c14b3f491c3a5e93f1e8756042567
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nds32 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from drivers/input/rmi4/rmi_spi.c:7:
   drivers/input/rmi4/rmi_spi.c:507:26: error: 'rmi_spi_suspend' undeclared here (not in a function); did you mean 'rmi_driver_suspend'?
     507 |  SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
         |                          ^~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:308:14: note: in expansion of macro 'pm_sleep_ptr'
     308 |  .suspend  = pm_sleep_ptr(suspend_fn), \
         |              ^~~~~~~~~~~~
   drivers/input/rmi4/rmi_spi.c:507:2: note: in expansion of macro 'SET_SYSTEM_SLEEP_PM_OPS'
     507 |  SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
         |  ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/input/rmi4/rmi_spi.c:507:43: error: 'rmi_spi_resume' undeclared here (not in a function); did you mean 'rmi_spi_pm'?
     507 |  SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
         |                                           ^~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:309:14: note: in expansion of macro 'pm_sleep_ptr'
     309 |  .resume   = pm_sleep_ptr(resume_fn), \
         |              ^~~~~~~~~~~~
   drivers/input/rmi4/rmi_spi.c:507:2: note: in expansion of macro 'SET_SYSTEM_SLEEP_PM_OPS'
     507 |  SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
         |  ^~~~~~~~~~~~~~~~~~~~~~~
>> drivers/input/rmi4/rmi_spi.c:508:21: error: 'rmi_spi_runtime_suspend' undeclared here (not in a function)
     508 |  SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
         |                     ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:332:21: note: in expansion of macro 'pm_ptr'
     332 |  .runtime_suspend = pm_ptr(suspend_fn), \
         |                     ^~~~~~
   drivers/input/rmi4/rmi_spi.c:508:2: note: in expansion of macro 'SET_RUNTIME_PM_OPS'
     508 |  SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
         |  ^~~~~~~~~~~~~~~~~~
>> drivers/input/rmi4/rmi_spi.c:508:46: error: 'rmi_spi_runtime_resume' undeclared here (not in a function)
     508 |  SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
         |                                              ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:333:21: note: in expansion of macro 'pm_ptr'
     333 |  .runtime_resume  = pm_ptr(resume_fn), \
         |                     ^~~~~~
   drivers/input/rmi4/rmi_spi.c:508:2: note: in expansion of macro 'SET_RUNTIME_PM_OPS'
     508 |  SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
         |  ^~~~~~~~~~~~~~~~~~
--
   In file included from include/linux/list.h:9,
                    from include/linux/rculist.h:10,
                    from include/linux/pid.h:5,
                    from include/linux/sched.h:14,
                    from include/linux/ratelimit.h:6,
                    from include/linux/dev_printk.h:16,
                    from include/linux/device.h:15,
                    from include/linux/backlight.h:12,
                    from drivers/video/backlight/ams369fg06.c:11:
>> drivers/video/backlight/ams369fg06.c:541:45: error: 'ams369fg06_suspend' undeclared here (not in a function); did you mean 'ams369fg06_probe'?
     541 | static SIMPLE_DEV_PM_OPS(ams369fg06_pm_ops, ams369fg06_suspend,
         |                                             ^~~~~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:308:14: note: in expansion of macro 'pm_sleep_ptr'
     308 |  .suspend  = pm_sleep_ptr(suspend_fn), \
         |              ^~~~~~~~~~~~
   include/linux/pm.h:342:2: note: in expansion of macro 'SET_SYSTEM_SLEEP_PM_OPS'
     342 |  SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
         |  ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/video/backlight/ams369fg06.c:541:8: note: in expansion of macro 'SIMPLE_DEV_PM_OPS'
     541 | static SIMPLE_DEV_PM_OPS(ams369fg06_pm_ops, ams369fg06_suspend,
         |        ^~~~~~~~~~~~~~~~~
>> drivers/video/backlight/ams369fg06.c:542:4: error: 'ams369fg06_resume' undeclared here (not in a function); did you mean 'ams369fg06_remove'?
     542 |    ams369fg06_resume);
         |    ^~~~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:309:14: note: in expansion of macro 'pm_sleep_ptr'
     309 |  .resume   = pm_sleep_ptr(resume_fn), \
         |              ^~~~~~~~~~~~
   include/linux/pm.h:342:2: note: in expansion of macro 'SET_SYSTEM_SLEEP_PM_OPS'
     342 |  SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
         |  ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/video/backlight/ams369fg06.c:541:8: note: in expansion of macro 'SIMPLE_DEV_PM_OPS'
     541 | static SIMPLE_DEV_PM_OPS(ams369fg06_pm_ops, ams369fg06_suspend,
         |        ^~~~~~~~~~~~~~~~~
--
   In file included from include/linux/delay.h:22,
                    from drivers/video/backlight/vgg2432a4.c:11:
>> drivers/video/backlight/vgg2432a4.c:246:44: error: 'vgg2432a4_suspend' undeclared here (not in a function); did you mean 'vgg2432a4_client'?
     246 | static SIMPLE_DEV_PM_OPS(vgg2432a4_pm_ops, vgg2432a4_suspend, vgg2432a4_resume);
         |                                            ^~~~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:308:14: note: in expansion of macro 'pm_sleep_ptr'
     308 |  .suspend  = pm_sleep_ptr(suspend_fn), \
         |              ^~~~~~~~~~~~
   include/linux/pm.h:342:2: note: in expansion of macro 'SET_SYSTEM_SLEEP_PM_OPS'
     342 |  SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
         |  ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/video/backlight/vgg2432a4.c:246:8: note: in expansion of macro 'SIMPLE_DEV_PM_OPS'
     246 | static SIMPLE_DEV_PM_OPS(vgg2432a4_pm_ops, vgg2432a4_suspend, vgg2432a4_resume);
         |        ^~~~~~~~~~~~~~~~~
>> drivers/video/backlight/vgg2432a4.c:246:63: error: 'vgg2432a4_resume' undeclared here (not in a function); did you mean 'vgg2432a4_remove'?
     246 | static SIMPLE_DEV_PM_OPS(vgg2432a4_pm_ops, vgg2432a4_suspend, vgg2432a4_resume);
         |                                                               ^~~~~~~~~~~~~~~~
   include/linux/kernel.h:41:38: note: in definition of macro 'PTR_IF'
      41 | #define PTR_IF(cond, ptr) ((cond) ? (ptr) : NULL)
         |                                      ^~~
   include/linux/pm.h:309:14: note: in expansion of macro 'pm_sleep_ptr'
     309 |  .resume   = pm_sleep_ptr(resume_fn), \
         |              ^~~~~~~~~~~~
   include/linux/pm.h:342:2: note: in expansion of macro 'SET_SYSTEM_SLEEP_PM_OPS'
     342 |  SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
         |  ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/video/backlight/vgg2432a4.c:246:8: note: in expansion of macro 'SIMPLE_DEV_PM_OPS'
     246 | static SIMPLE_DEV_PM_OPS(vgg2432a4_pm_ops, vgg2432a4_suspend, vgg2432a4_resume);
         |        ^~~~~~~~~~~~~~~~~


vim +/rmi_spi_runtime_suspend +508 drivers/input/rmi4/rmi_spi.c

8d99758dee31ff Andrew Duggan 2016-03-10  505  
8d99758dee31ff Andrew Duggan 2016-03-10  506  static const struct dev_pm_ops rmi_spi_pm = {
8d99758dee31ff Andrew Duggan 2016-03-10 @507  	SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
8d99758dee31ff Andrew Duggan 2016-03-10 @508  	SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
8d99758dee31ff Andrew Duggan 2016-03-10  509  			   NULL)
8d99758dee31ff Andrew Duggan 2016-03-10  510  };
8d99758dee31ff Andrew Duggan 2016-03-10  511  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Masahiro Yamada April 9, 2021, 3:17 a.m. | #3
On Fri, Apr 9, 2021 at 6:30 AM Arnd Bergmann <arnd@arndb.de> wrote:
>

> On Thu, Apr 8, 2021 at 11:00 PM Masahiro Yamada <masahiroy@kernel.org> wrote:

> >

> > Drivers typically surround suspend and resume callbacks with #ifdef

> > CONFIG_PM(_SLEEP) or mark them as __maybe_unused in order to avoid

> > -Wunused-const-variable warnings.

> >

> > With this commit, drivers will be able to remove #ifdef CONFIG_PM(_SLEEP)

> > and __maybe_unsed because unused functions are dropped by the compiler

> > instead of the preprocessor.

> >

> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

>

> I tried this before and could not get it to work right.

>

> >

> > -#ifdef CONFIG_PM_SLEEP

> > +#define pm_ptr(_ptr)           PTR_IF(IS_ENABLED(CONFIG_PM), _ptr)

> > +#define pm_sleep_ptr(_ptr)     PTR_IF(IS_ENABLED(CONFIG_PM_SLEEP), _ptr)

> > +

> >  #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \

> > -       .suspend = suspend_fn, \

> > -       .resume = resume_fn, \

> > -       .freeze = suspend_fn, \

> > -       .thaw = resume_fn, \

> > -       .poweroff = suspend_fn, \

> > -       .restore = resume_fn,

> > -#else

> > -#define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)

> > -#endif

> > +       .suspend  = pm_sleep_ptr(suspend_fn), \

> > +       .resume   = pm_sleep_ptr(resume_fn), \

> > +       .freeze   = pm_sleep_ptr(suspend_fn), \

> > +       .thaw     = pm_sleep_ptr(resume_fn), \

> > +       .poweroff = pm_sleep_ptr(suspend_fn), \

> > +       .restore  = pm_sleep_ptr(resume_fn),

>

> The problem that I think you inevitably hit is that you run into a missing

> declaration for any driver that still uses an #ifdef around a static

> function.

>

> The only way I can see us doing this is to create a new set of

> macros that behave like the version you propose here but leave

> the old macros in place until the last such #ifdef has been removed.

>

>        Arnd


Agh, you are right.
We cannot change all the callsites atomically due to the huge amount of users.

-- 
Best Regards
Masahiro Yamada

Patch

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 482313a8ccfc..ca764566692a 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -301,50 +301,37 @@  struct dev_pm_ops {
 	int (*runtime_idle)(struct device *dev);
 };
 
-#ifdef CONFIG_PM_SLEEP
+#define pm_ptr(_ptr)		PTR_IF(IS_ENABLED(CONFIG_PM), _ptr)
+#define pm_sleep_ptr(_ptr)	PTR_IF(IS_ENABLED(CONFIG_PM_SLEEP), _ptr)
+
 #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
-	.suspend = suspend_fn, \
-	.resume = resume_fn, \
-	.freeze = suspend_fn, \
-	.thaw = resume_fn, \
-	.poweroff = suspend_fn, \
-	.restore = resume_fn,
-#else
-#define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)
-#endif
+	.suspend  = pm_sleep_ptr(suspend_fn), \
+	.resume   = pm_sleep_ptr(resume_fn), \
+	.freeze   = pm_sleep_ptr(suspend_fn), \
+	.thaw     = pm_sleep_ptr(resume_fn), \
+	.poweroff = pm_sleep_ptr(suspend_fn), \
+	.restore  = pm_sleep_ptr(resume_fn),
 
-#ifdef CONFIG_PM_SLEEP
 #define SET_LATE_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
-	.suspend_late = suspend_fn, \
-	.resume_early = resume_fn, \
-	.freeze_late = suspend_fn, \
-	.thaw_early = resume_fn, \
-	.poweroff_late = suspend_fn, \
-	.restore_early = resume_fn,
-#else
-#define SET_LATE_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)
-#endif
+	.suspend_late  = pm_sleep_ptr(suspend_fn), \
+	.resume_early  = pm_sleep_ptr(resume_fn), \
+	.freeze_late   = pm_sleep_ptr(suspend_fn), \
+	.thaw_early    = pm_sleep_ptr(resume_fn), \
+	.poweroff_late = pm_sleep_ptr(suspend_fn), \
+	.restore_early = pm_sleep_ptr(resume_fn),
 
-#ifdef CONFIG_PM_SLEEP
 #define SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
-	.suspend_noirq = suspend_fn, \
-	.resume_noirq = resume_fn, \
-	.freeze_noirq = suspend_fn, \
-	.thaw_noirq = resume_fn, \
-	.poweroff_noirq = suspend_fn, \
-	.restore_noirq = resume_fn,
-#else
-#define SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)
-#endif
+	.suspend_noirq  = pm_sleep_ptr(suspend_fn), \
+	.resume_noirq   = pm_sleep_ptr(resume_fn), \
+	.freeze_noirq   = pm_sleep_ptr(suspend_fn), \
+	.thaw_noirq     = pm_sleep_ptr(resume_fn), \
+	.poweroff_noirq = pm_sleep_ptr(suspend_fn), \
+	.restore_noirq  = pm_sleep_ptr(resume_fn),
 
-#ifdef CONFIG_PM
 #define SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \
-	.runtime_suspend = suspend_fn, \
-	.runtime_resume = resume_fn, \
-	.runtime_idle = idle_fn,
-#else
-#define SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn)
-#endif
+	.runtime_suspend = pm_ptr(suspend_fn), \
+	.runtime_resume  = pm_ptr(resume_fn), \
+	.runtime_idle    = pm_ptr(idle_fn),
 
 /*
  * Use this if you want to use the same suspend and resume callbacks for suspend
@@ -374,12 +361,6 @@  const struct dev_pm_ops __maybe_unused name = { \
 	SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \
 }
 
-#ifdef CONFIG_PM
-#define pm_ptr(_ptr) (_ptr)
-#else
-#define pm_ptr(_ptr) NULL
-#endif
-
 /*
  * PM_EVENT_ messages
  *