[PATCH] of: drop symbols declared by _OF_DECLARE() from modules

[PATCH] of: drop symbols declared by _OF_DECLARE() from modules

[Masahiro Yamada]

The users of this macro (OF_EARLYCON_DECLARE, CLK_OF_DECLARE,
IRQCHIP_DECLARE, etc.) are only parsed in the early boot stage.

Such symbols contained in modules are never used.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

OF_EARLYCON_DECLARE() is declared in several tristate drivers.

This patch makes each low-level driver be free from
taking care of it.

See this patch
https://patchwork.kernel.org/patch/8028771/


 include/linux/of.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/of.h b/include/linux/of.h
index dd10626..dc6e396 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -929,7 +929,7 @@ static inline int of_get_available_child_count(const struct device_node *np)
 	return num;
 }
 
-#ifdef CONFIG_OF
+#if defined(CONFIG_OF) && !defined(MODULE)
 #define _OF_DECLARE(table, name, compat, fn, fn_type)			\
 	static const struct of_device_id __of_table_##name		\
 		__used __section(__##table##_of_table)			\
-- 
1.9.1

[PATCH] of: drop symbols declared by _OF_DECLARE() from modules

[Arnd Bergmann]

On Thursday 14 January 2016 13:33:06 Masahiro Yamada wrote:
> 
> -#ifdef CONFIG_OF
> +#if defined(CONFIG_OF) && !defined(MODULE)
>  #define _OF_DECLARE(table, name, compat, fn, fn_type)                  \
>         static const struct of_device_id __of_table_##name              \
>                 __used __section(__##table##_of_table)                  \
> -- 
> 

Doesn't this lead to "unused function" warnings? Maybe we can change the "__used"
into "__unused" when MODULE is set, so the compiler will automatically
drop all code that is only referenced from the entry.

	Arnd

[PATCH] of: drop symbols declared by _OF_DECLARE() from modules

[Masahiro Yamada]

Hi Arnd,

2016-01-14 19:14 GMT+09:00 Arnd Bergmann <arnd@arndb.de>:
> On Thursday 14 January 2016 13:33:06 Masahiro Yamada wrote:
>>
>> -#ifdef CONFIG_OF
>> +#if defined(CONFIG_OF) && !defined(MODULE)
>>  #define _OF_DECLARE(table, name, compat, fn, fn_type)                  \
>>         static const struct of_device_id __of_table_##name              \
>>                 __used __section(__##table##_of_table)                  \
>> --
>>
>
> Doesn't this lead to "unused function" warnings? Maybe we can change the "__used"
> into "__unused" when MODULE is set,

Yes, this is my intention.

I think this patch does so,
unless I am missing something...


  #if defined(CONFIG_OF) && !defined(MODULE)
          __used
  #else
          __unused
  #endif



> so the compiler will automatically
> drop all code that is only referenced from the entry.


-- 
Best Regards
Masahiro Yamada

[PATCH] of: drop symbols declared by _OF_DECLARE() from modules

[Arnd Bergmann]

On Thursday 14 January 2016 19:21:21 Masahiro Yamada wrote:
> Yes, this is my intention.
> 
> I think this patch does so,
> unless I am missing something...
> 
> 
>   #if defined(CONFIG_OF) && !defined(MODULE)
>           __used
>   #else
>           __unused
>   #endif
> 
> 

Ah, got it. You are right, I just missed that because the #else
part was not in the context that I saw in the patch and I was too lazy
to actually look at the file.

Acked-by: Arnd Bergmann <arnd@arndb.de>

	Arnd