[PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Raphael Gallais-Pou]

Letting the compiler remove these functions when the kernel is built
without CONFIG_PM_SLEEP support is simpler and less error prone than the
use of #ifdef based kernel configuration guards.

Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
---
Changes in v2:
  - Split serie in single patches
  - Remove irrelevant 'Link:' from commit log
  - Link to v1: https://lore.kernel.org/r/20241229-update_pm_macro-v1-4-c7d4c4856336@gmail.com
---
 drivers/ata/ahci_st.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
index 6b9b4a1dfa15..4336c8a6e208 100644
--- a/drivers/ata/ahci_st.c
+++ b/drivers/ata/ahci_st.c
@@ -176,7 +176,6 @@ static int st_ahci_probe(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int st_ahci_suspend(struct device *dev)
 {
 	struct ata_host *host = dev_get_drvdata(dev);
@@ -221,9 +220,8 @@ static int st_ahci_resume(struct device *dev)
 
 	return ahci_platform_resume_host(dev);
 }
-#endif
 
-static SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
 
 static const struct of_device_id st_ahci_match[] = {
 	{ .compatible = "st,ahci", },
@@ -234,7 +232,7 @@ MODULE_DEVICE_TABLE(of, st_ahci_match);
 static struct platform_driver st_ahci_driver = {
 	.driver = {
 		.name = DRV_NAME,
-		.pm = &st_ahci_pm_ops,
+		.pm = pm_sleep_ptr(&st_ahci_pm_ops),
 		.of_match_table = st_ahci_match,
 	},
 	.probe = st_ahci_probe,
-- 
2.47.1

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Damien Le Moal]

On 1/10/25 02:54, Raphael Gallais-Pou wrote:
> Letting the compiler remove these functions when the kernel is built
> without CONFIG_PM_SLEEP support is simpler and less error prone than the
> use of #ifdef based kernel configuration guards.
> 
> Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
> ---
> Changes in v2:
>   - Split serie in single patches
>   - Remove irrelevant 'Link:' from commit log
>   - Link to v1: https://lore.kernel.org/r/20241229-update_pm_macro-v1-4-c7d4c4856336@gmail.com
> ---
>  drivers/ata/ahci_st.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
> index 6b9b4a1dfa15..4336c8a6e208 100644
> --- a/drivers/ata/ahci_st.c
> +++ b/drivers/ata/ahci_st.c
> @@ -176,7 +176,6 @@ static int st_ahci_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -#ifdef CONFIG_PM_SLEEP
>  static int st_ahci_suspend(struct device *dev)
>  {
>  	struct ata_host *host = dev_get_drvdata(dev);
> @@ -221,9 +220,8 @@ static int st_ahci_resume(struct device *dev)
>  
>  	return ahci_platform_resume_host(dev);
>  }
> -#endif

I do not think you can remove the ifdef here. Otherwise, there is going to be a
compilation warning when CONFIG_PM_SLEEP is not enabled. No ?

>  
> -static SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
> +static DEFINE_SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
>  
>  static const struct of_device_id st_ahci_match[] = {
>  	{ .compatible = "st,ahci", },
> @@ -234,7 +232,7 @@ MODULE_DEVICE_TABLE(of, st_ahci_match);
>  static struct platform_driver st_ahci_driver = {
>  	.driver = {
>  		.name = DRV_NAME,
> -		.pm = &st_ahci_pm_ops,
> +		.pm = pm_sleep_ptr(&st_ahci_pm_ops),
>  		.of_match_table = st_ahci_match,
>  	},
>  	.probe = st_ahci_probe,


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Niklas Cassel]

On Thu, Jan 09, 2025 at 06:54:27PM +0100, Raphael Gallais-Pou wrote:
> Letting the compiler remove these functions when the kernel is built
> without CONFIG_PM_SLEEP support is simpler and less error prone than the
> use of #ifdef based kernel configuration guards.
> 
> Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
> ---
> Changes in v2:
>   - Split serie in single patches
>   - Remove irrelevant 'Link:' from commit log
>   - Link to v1: https://lore.kernel.org/r/20241229-update_pm_macro-v1-4-c7d4c4856336@gmail.com
> ---
>  drivers/ata/ahci_st.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
> index 6b9b4a1dfa15..4336c8a6e208 100644
> --- a/drivers/ata/ahci_st.c
> +++ b/drivers/ata/ahci_st.c
> @@ -176,7 +176,6 @@ static int st_ahci_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -#ifdef CONFIG_PM_SLEEP
>  static int st_ahci_suspend(struct device *dev)
>  {
>  	struct ata_host *host = dev_get_drvdata(dev);
> @@ -221,9 +220,8 @@ static int st_ahci_resume(struct device *dev)
>  
>  	return ahci_platform_resume_host(dev);
>  }
> -#endif
>  
> -static SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
> +static DEFINE_SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
>  
>  static const struct of_device_id st_ahci_match[] = {
>  	{ .compatible = "st,ahci", },
> @@ -234,7 +232,7 @@ MODULE_DEVICE_TABLE(of, st_ahci_match);
>  static struct platform_driver st_ahci_driver = {
>  	.driver = {
>  		.name = DRV_NAME,
> -		.pm = &st_ahci_pm_ops,
> +		.pm = pm_sleep_ptr(&st_ahci_pm_ops),
>  		.of_match_table = st_ahci_match,
>  	},
>  	.probe = st_ahci_probe,
> -- 
> 2.47.1
> 

Reviewed-by: Niklas Cassel <cassel@kernel.org>

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Niklas Cassel]

On Fri, Jan 10, 2025 at 02:19:06PM +0900, Damien Le Moal wrote:
> On 1/10/25 02:54, Raphael Gallais-Pou wrote:
> > Letting the compiler remove these functions when the kernel is built
> > without CONFIG_PM_SLEEP support is simpler and less error prone than the
> > use of #ifdef based kernel configuration guards.
> > 
> > Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
> > ---
> > Changes in v2:
> >   - Split serie in single patches
> >   - Remove irrelevant 'Link:' from commit log
> >   - Link to v1: https://lore.kernel.org/r/20241229-update_pm_macro-v1-4-c7d4c4856336@gmail.com
> > ---
> >  drivers/ata/ahci_st.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
> > index 6b9b4a1dfa15..4336c8a6e208 100644
> > --- a/drivers/ata/ahci_st.c
> > +++ b/drivers/ata/ahci_st.c
> > @@ -176,7 +176,6 @@ static int st_ahci_probe(struct platform_device *pdev)
> >  	return 0;
> >  }
> >  
> > -#ifdef CONFIG_PM_SLEEP
> >  static int st_ahci_suspend(struct device *dev)
> >  {
> >  	struct ata_host *host = dev_get_drvdata(dev);
> > @@ -221,9 +220,8 @@ static int st_ahci_resume(struct device *dev)
> >  
> >  	return ahci_platform_resume_host(dev);
> >  }
> > -#endif
> 
> I do not think you can remove the ifdef here. Otherwise, there is going to be a
> compilation warning when CONFIG_PM_SLEEP is not enabled. No ?

Look at the pm_sleep_ptr macro:
include/linux/pm.h:#define pm_sleep_ptr(_ptr) PTR_IF(IS_ENABLED(CONFIG_PM_SLEEP), (_ptr))

I would expect the function should be optimized out by the compiler
using dead code elimination.

Raphael, perhaps you could show the before and after output
using ./scripts/bloat-o-meter ?
(When the config is not enabled: before and after your patch.)


> 
> >  
> > -static SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
> > +static DEFINE_SIMPLE_DEV_PM_OPS(st_ahci_pm_ops, st_ahci_suspend, st_ahci_resume);
> >  
> >  static const struct of_device_id st_ahci_match[] = {
> >  	{ .compatible = "st,ahci", },
> > @@ -234,7 +232,7 @@ MODULE_DEVICE_TABLE(of, st_ahci_match);
> >  static struct platform_driver st_ahci_driver = {
> >  	.driver = {
> >  		.name = DRV_NAME,
> > -		.pm = &st_ahci_pm_ops,
> > +		.pm = pm_sleep_ptr(&st_ahci_pm_ops),
> >  		.of_match_table = st_ahci_match,
> >  	},
> >  	.probe = st_ahci_probe,
> 
> 
> -- 
> Damien Le Moal
> Western Digital Research

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Damien Le Moal]

On 1/10/25 20:23, Niklas Cassel wrote:
>>> -#ifdef CONFIG_PM_SLEEP
>>>  static int st_ahci_suspend(struct device *dev)
>>>  {
>>>  	struct ata_host *host = dev_get_drvdata(dev);
>>> @@ -221,9 +220,8 @@ static int st_ahci_resume(struct device *dev)
>>>  
>>>  	return ahci_platform_resume_host(dev);
>>>  }
>>> -#endif
>>
>> I do not think you can remove the ifdef here. Otherwise, there is going to be a
>> compilation warning when CONFIG_PM_SLEEP is not enabled. No ?
> 
> Look at the pm_sleep_ptr macro:
> include/linux/pm.h:#define pm_sleep_ptr(_ptr) PTR_IF(IS_ENABLED(CONFIG_PM_SLEEP), (_ptr))
> 
> I would expect the function should be optimized out by the compiler
> using dead code elimination.

Indeed. Just tried and no warning. I was expecting a "defined but not used"
warning, but none showed up. So all good.

> Raphael, perhaps you could show the before and after output
> using ./scripts/bloat-o-meter ?
> (When the config is not enabled: before and after your patch.)

No need to do that I guess. But there are 17 other ata driver that set .pm
operations. What about these ? Don't they need the same treatment as ahci_st ?
15 of these also use SIMPLE_DEV_PM_OPS() which can be replaced with
DEFINE_SIMPLE_DEV_PM_OPS() also, no ?

Do you want us to do that cleanup ? (fine with me).

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Raphaël Gallais-Pou]

Le 10/01/2025 à 13:02, Damien Le Moal a écrit :
> On 1/10/25 20:23, Niklas Cassel wrote:
>>>> -#ifdef CONFIG_PM_SLEEP
>>>>   static int st_ahci_suspend(struct device *dev)
>>>>   {
>>>>   	struct ata_host *host = dev_get_drvdata(dev);
>>>> @@ -221,9 +220,8 @@ static int st_ahci_resume(struct device *dev)
>>>>   
>>>>   	return ahci_platform_resume_host(dev);
>>>>   }
>>>> -#endif
>>>
>>> I do not think you can remove the ifdef here. Otherwise, there is going to be a
>>> compilation warning when CONFIG_PM_SLEEP is not enabled. No ?
>>
>> Look at the pm_sleep_ptr macro:
>> include/linux/pm.h:#define pm_sleep_ptr(_ptr) PTR_IF(IS_ENABLED(CONFIG_PM_SLEEP), (_ptr))
>>
>> I would expect the function should be optimized out by the compiler
>> using dead code elimination.
> 
> Indeed. Just tried and no warning. I was expecting a "defined but not used"
> warning, but none showed up. So all good.
> 
>> Raphael, perhaps you could show the before and after output
>> using ./scripts/bloat-o-meter ?
>> (When the config is not enabled: before and after your patch.)
Hi,

I have not used the bloat-o-meter until now, thanks ! :)
Here are my results:


   * with the configuration

$ ./scripts/bloat-o-meter ahci_st_no_patch_pm.o ahci_st_patch_pm.o
add/remove: 1/1 grow/shrink: 0/0 up/down: 4/-4 (0)
Function                                     old     new   delta
__initcall__kmod_ahci_st__384_241_st_ahci_driver_init6       -       4 
    +4
__initcall__kmod_ahci_st__384_243_st_ahci_driver_init6       4       - 
    -4
Total: Before=2200, After=2200, chg +0.00%


   * without the configuration

$ ./scripts/bloat-o-meter ahci_st_no_patch_no_pm.o ahci_st_patch_no_pm.o
add/remove: 1/2 grow/shrink: 0/0 up/down: 4/-96 (-92)
Function                                     old     new   delta
__initcall__kmod_ahci_st__383_241_st_ahci_driver_init6       -       4 
    +4
__initcall__kmod_ahci_st__383_243_st_ahci_driver_init6       4       - 
    -4
st_ahci_pm_ops                                92       -     -92
Total: Before=1904, After=1812, chg -4.83%


Looks like the patch shrinks a bit more the driver. I also tested, so we 
should be fine I think.
> 
> No need to do that I guess. But there are 17 other ata driver that set .pm
> operations. What about these ? Don't they need the same treatment as ahci_st ?
> 15 of these also use SIMPLE_DEV_PM_OPS() which can be replaced with
> DEFINE_SIMPLE_DEV_PM_OPS() also, no ?
> 
> Do you want us to do that cleanup ? (fine with me).

Regarding the other ata drivers, if you have the patience I can do this 
in a few weeks.  There is other things on the stove I would like to do.

Regards,
Raphaël
> 

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Damien Le Moal]

On 1/14/25 05:28, Raphaël Gallais-Pou wrote:
>> Do you want us to do that cleanup ? (fine with me).
> 
> Regarding the other ata drivers, if you have the patience I can do this 
> in a few weeks.  There is other things on the stove I would like to do.

OK. We will work on this.


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Raphaël Gallais-Pou]

Le 14/01/2025 à 01:59, Damien Le Moal a écrit :
> On 1/14/25 05:28, Raphaël Gallais-Pou wrote:
>>> Do you want us to do that cleanup ? (fine with me).
>>
>> Regarding the other ata drivers, if you have the patience I can do this
>> in a few weeks.  There is other things on the stove I would like to do.
> 
> OK. We will work on this.

Sorry to change my plans,  I actually started working on this.  Is this 
okay to let me handle this ?  I will try to submit something promptly.

Thanks,
Raphaël
> 
> 

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Niklas Cassel]

On Wed, Jan 15, 2025 at 09:28:08AM +0100, Raphaël Gallais-Pou wrote:
> Le 14/01/2025 à 01:59, Damien Le Moal a écrit :
> > On 1/14/25 05:28, Raphaël Gallais-Pou wrote:
> > > > Do you want us to do that cleanup ? (fine with me).
> > > 
> > > Regarding the other ata drivers, if you have the patience I can do this
> > > in a few weeks.  There is other things on the stove I would like to do.
> > 
> > OK. We will work on this.
> 
> Sorry to change my plans,  I actually started working on this.  Is this okay
> to let me handle this ?  I will try to submit something promptly.

Of course, I know that both me and Damien are quite busy at the moment.

Looking forward to your patches!


Kind regards,
Niklas

Re: [PATCH v2] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()

[Niklas Cassel]

On Thu, 09 Jan 2025 18:54:27 +0100, Raphael Gallais-Pou wrote:
> Letting the compiler remove these functions when the kernel is built
> without CONFIG_PM_SLEEP support is simpler and less error prone than the
> use of #ifdef based kernel configuration guards.
> 
> 

Applied to libata/linux.git (for-6.14), thanks!

[1/1] ahci: st: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr()
      https://git.kernel.org/libata/linux/c/f2809aa4

Kind regards,
Niklas