[PATCH] kconfig.h: remove config_enabled() macro

[PATCH] kconfig.h: remove config_enabled() macro

[Masahiro Yamada]

The use of config_enabled() is ambiguous.  For config options,
IS_ENABLED(), IS_REACHABLE(), etc. will make intention clearer.
Sometimes config_enabled() has been used for non-config options
because it is useful to check whether the given symbol is defined
or not.

I have been tackling on deprecating config_enabled(), and now is the
time to finish this work.

Some new users have appeared for v4.9-rc1, but it is trivial to
replace them:

 - arch/x86/mm/kaslr.c
  replace config_enabled() with IS_ENABLED() because
  CONFIG_X86_ESPFIX64 and CONFIG_EFI are boolean.

 - include/asm-generic/export.h
  replace config_enabled() with __is_defined().

Then, config_enabled() can be removed now.

Going forward, please use IS_ENABLED(), IS_REACHABLE(), etc. for
config options, and __is_defined() for non-config symbols.

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

 arch/x86/mm/kaslr.c          | 6 +++---
 include/asm-generic/export.h | 2 +-
 include/linux/kconfig.h      | 5 ++---
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index ddd2661..887e571 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -104,10 +104,10 @@ void __init kernel_randomize_memory(void)
 	 * consistent with the vaddr_start/vaddr_end variables.
 	 */
 	BUILD_BUG_ON(vaddr_start >= vaddr_end);
-	BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
+	BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_ESPFIX64) &&
 		     vaddr_end >= EFI_VA_START);
-	BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
-		      config_enabled(CONFIG_EFI)) &&
+	BUILD_BUG_ON((IS_ENABLED(CONFIG_X86_ESPFIX64) ||
+		      IS_ENABLED(CONFIG_EFI)) &&
 		     vaddr_end >= __START_KERNEL_map);
 	BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
 
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 43199a0..63554e9 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -70,7 +70,7 @@
 #include <generated/autoksyms.h>
 
 #define __EXPORT_SYMBOL(sym, val, sec)				\
-	__cond_export_sym(sym, val, sec, config_enabled(__KSYM_##sym))
+	__cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym))
 #define __cond_export_sym(sym, val, sec, conf)			\
 	___cond_export_sym(sym, val, sec, conf)
 #define ___cond_export_sym(sym, val, sec, enabled)		\
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index 15ec117..8f2e059 100644
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -31,7 +31,6 @@
  * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
  * the last step cherry picks the 2nd arg, we get a zero.
  */
-#define config_enabled(cfg)		___is_defined(cfg)
 #define __is_defined(x)			___is_defined(x)
 #define ___is_defined(val)		____is_defined(__ARG_PLACEHOLDER_##val)
 #define ____is_defined(arg1_or_junk)	__take_second_arg(arg1_or_junk 1, 0)
@@ -41,13 +40,13 @@
  * otherwise. For boolean options, this is equivalent to
  * IS_ENABLED(CONFIG_FOO).
  */
-#define IS_BUILTIN(option) config_enabled(option)
+#define IS_BUILTIN(option) __is_defined(option)
 
 /*
  * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
  * otherwise.
  */
-#define IS_MODULE(option) config_enabled(option##_MODULE)
+#define IS_MODULE(option) __is_defined(option##_MODULE)
 
 /*
  * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled
-- 
1.9.1

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Ingo Molnar]

* Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> The use of config_enabled() is ambiguous.  For config options,
> IS_ENABLED(), IS_REACHABLE(), etc. will make intention clearer.
> Sometimes config_enabled() has been used for non-config options
> because it is useful to check whether the given symbol is defined
> or not.
> 
> I have been tackling on deprecating config_enabled(), and now is the
> time to finish this work.
> 
> Some new users have appeared for v4.9-rc1, but it is trivial to
> replace them:
> 
>  - arch/x86/mm/kaslr.c
>   replace config_enabled() with IS_ENABLED() because
>   CONFIG_X86_ESPFIX64 and CONFIG_EFI are boolean.

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo

Re: [PATCH] kconfig.h: remove config_enabled() macro

[hpa]

On October 16, 2016 4:07:58 AM PDT, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>The use of config_enabled() is ambiguous.  For config options,
>IS_ENABLED(), IS_REACHABLE(), etc. will make intention clearer.
>Sometimes config_enabled() has been used for non-config options
>because it is useful to check whether the given symbol is defined
>or not.
>
>I have been tackling on deprecating config_enabled(), and now is the
>time to finish this work.
>
>Some new users have appeared for v4.9-rc1, but it is trivial to
>replace them:
>
> - arch/x86/mm/kaslr.c
>  replace config_enabled() with IS_ENABLED() because
>  CONFIG_X86_ESPFIX64 and CONFIG_EFI are boolean.
>
> - include/asm-generic/export.h
>  replace config_enabled() with __is_defined().
>
>Then, config_enabled() can be removed now.
>
>Going forward, please use IS_ENABLED(), IS_REACHABLE(), etc. for
>config options, and __is_defined() for non-config symbols.
>
>Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>---
>
> arch/x86/mm/kaslr.c          | 6 +++---
> include/asm-generic/export.h | 2 +-
> include/linux/kconfig.h      | 5 ++---
> 3 files changed, 6 insertions(+), 7 deletions(-)
>
>diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
>index ddd2661..887e571 100644
>--- a/arch/x86/mm/kaslr.c
>+++ b/arch/x86/mm/kaslr.c
>@@ -104,10 +104,10 @@ void __init kernel_randomize_memory(void)
> 	 * consistent with the vaddr_start/vaddr_end variables.
> 	 */
> 	BUILD_BUG_ON(vaddr_start >= vaddr_end);
>-	BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
>+	BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_ESPFIX64) &&
> 		     vaddr_end >= EFI_VA_START);
>-	BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
>-		      config_enabled(CONFIG_EFI)) &&
>+	BUILD_BUG_ON((IS_ENABLED(CONFIG_X86_ESPFIX64) ||
>+		      IS_ENABLED(CONFIG_EFI)) &&
> 		     vaddr_end >= __START_KERNEL_map);
> 	BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
> 
>diff --git a/include/asm-generic/export.h
>b/include/asm-generic/export.h
>index 43199a0..63554e9 100644
>--- a/include/asm-generic/export.h
>+++ b/include/asm-generic/export.h
>@@ -70,7 +70,7 @@
> #include <generated/autoksyms.h>
> 
> #define __EXPORT_SYMBOL(sym, val, sec)				\
>-	__cond_export_sym(sym, val, sec, config_enabled(__KSYM_##sym))
>+	__cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym))
> #define __cond_export_sym(sym, val, sec, conf)			\
> 	___cond_export_sym(sym, val, sec, conf)
> #define ___cond_export_sym(sym, val, sec, enabled)		\
>diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
>index 15ec117..8f2e059 100644
>--- a/include/linux/kconfig.h
>+++ b/include/linux/kconfig.h
>@@ -31,7 +31,6 @@
>* When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and
>when
>  * the last step cherry picks the 2nd arg, we get a zero.
>  */
>-#define config_enabled(cfg)		___is_defined(cfg)
> #define __is_defined(x)			___is_defined(x)
> #define ___is_defined(val)		____is_defined(__ARG_PLACEHOLDER_##val)
>#define ____is_defined(arg1_or_junk)	__take_second_arg(arg1_or_junk 1,
>0)
>@@ -41,13 +40,13 @@
>  * otherwise. For boolean options, this is equivalent to
>  * IS_ENABLED(CONFIG_FOO).
>  */
>-#define IS_BUILTIN(option) config_enabled(option)
>+#define IS_BUILTIN(option) __is_defined(option)
> 
> /*
>  * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
>  * otherwise.
>  */
>-#define IS_MODULE(option) config_enabled(option##_MODULE)
>+#define IS_MODULE(option) __is_defined(option##_MODULE)
> 
> /*
>  * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled

How is __is_defined() different from defined()?
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Masahiro Yamada]

Hi Peter.


2016-10-17 3:44 GMT+09:00  <hpa@zytor.com>:
>
> How is __is_defined() different from defined()?



defined() can be used only in pre-processor's #if context, like

    #if defined(FOO)
          ...
    #endif



__is_defined() can be used more flexibly.




-- 
Best Regards
Masahiro Yamada

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Paul Bolle]

Masahiro,

A few comments regarding, I guess, future work.

On Sun, 2016-10-16 at 20:07 +0900, Masahiro Yamada wrote:
> The use of config_enabled() is ambiguous.  For config options,
> IS_ENABLED(), IS_REACHABLE(), etc. will make intention clearer.
> Sometimes config_enabled() has been used for non-config options
> because it is useful to check whether the given symbol is defined
> or not.
> 
> I have been tackling on deprecating config_enabled(), and now is the
> time to finish this work.
> 
> Some new users have appeared for v4.9-rc1, but it is trivial to
> replace them:
> 
>  - arch/x86/mm/kaslr.c
>   replace config_enabled() with IS_ENABLED() because
>   CONFIG_X86_ESPFIX64 and CONFIG_EFI are boolean.
> 
>  - include/asm-generic/export.h
>   replace config_enabled() with __is_defined().
> 
> Then, config_enabled() can be removed now.
> 
> Going forward, please use IS_ENABLED(), IS_REACHABLE(), etc. for
> config options, and __is_defined() for non-config symbols.

There are about a dozen instances of IS_ENABLED() that target something
other than a kconfig macros. Are you planning to convert those to
__is_defined() too? 

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

> --- a/include/linux/kconfig.h
> +++ b/include/linux/kconfig.h
> @@ -31,7 +31,6 @@
>   * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
>   * the last step cherry picks the 2nd arg, we get a zero.
>   */
> -#define config_enabled(cfg)		___is_defined(cfg)

Is there a reason to keep using the double underscore prefix?

>  #define __is_defined(x)			___is_defined(x)
>  #define ___is_defined(val)		____is_defined(__ARG_PLACEHOLDER_##val)
>  #define ____is_defined(arg1_or_junk)	__take_second_arg(arg1_or_junk 1, 0)

__is_defined() is now meant to be used generally, and not just on
kconfig macros. Can it be moved into another header?


Paul Bolle

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Masahiro Yamada]

Hi Paul,



2016-10-20 19:04 GMT+09:00 Paul Bolle <pebolle@tiscali.nl>:
> Masahiro,
>
> A few comments regarding, I guess, future work.
>
> On Sun, 2016-10-16 at 20:07 +0900, Masahiro Yamada wrote:
>> The use of config_enabled() is ambiguous.  For config options,
>> IS_ENABLED(), IS_REACHABLE(), etc. will make intention clearer.
>> Sometimes config_enabled() has been used for non-config options
>> because it is useful to check whether the given symbol is defined
>> or not.
>>
>> I have been tackling on deprecating config_enabled(), and now is the
>> time to finish this work.
>>
>> Some new users have appeared for v4.9-rc1, but it is trivial to
>> replace them:
>>
>>  - arch/x86/mm/kaslr.c
>>   replace config_enabled() with IS_ENABLED() because
>>   CONFIG_X86_ESPFIX64 and CONFIG_EFI are boolean.
>>
>>  - include/asm-generic/export.h
>>   replace config_enabled() with __is_defined().
>>
>> Then, config_enabled() can be removed now.
>>
>> Going forward, please use IS_ENABLED(), IS_REACHABLE(), etc. for
>> config options, and __is_defined() for non-config symbols.
>
> There are about a dozen instances of IS_ENABLED() that target something
> other than a kconfig macros. Are you planning to convert those to
> __is_defined() too?

I did not notice that, but looks like there are some to be checked.


$ git grep '[^A-Za-z0-9_]IS_ENABLED([^C]'
arch/arc/include/asm/setup.h:#define IS_USED_CFG(cfg)
IS_USED_RUN(IS_ENABLED(cfg))
arch/arm64/include/asm/alternative.h:   __ALTERNATIVE_CFG(oldinstr,
newinstr, feature, IS_ENABLED(cfg))
arch/arm64/include/asm/alternative.h:   alternative_insn insn1, insn2,
cap, IS_ENABLED(cfg)
drivers/crypto/sahara.c:        if (!IS_ENABLED(DEBUG))
drivers/crypto/sahara.c:        if (!IS_ENABLED(DEBUG))
drivers/crypto/sahara.c:        if (!IS_ENABLED(DEBUG))
drivers/gpu/drm/exynos/exynos_drm_drv.c:#define DRV_PTR(drv, cond)
(IS_ENABLED(cond) ? &drv : NULL)
include/asm-generic/vmlinux.lds.h:#define OF_TABLE(cfg, name)
__OF_TABLE(IS_ENABLED(cfg), name)
include/linux/init.h:   int var = IS_ENABLED(config);
                 \
include/linux/kconfig.h: * This is similar to IS_ENABLED(), but
returns false when invoked from
include/linux/kconfig.h:#define IS_ENABLED(option)
__or(IS_BUILTIN(option), IS_MODULE(option))
kernel/locking/locktorture.c:int torture_runnable = IS_ENABLED(MODULE);
kernel/rcu/rcuperf.c:static int perf_runnable = IS_ENABLED(MODULE);
kernel/rcu/rcutorture.c:static int torture_runnable = IS_ENABLED(MODULE);
scripts/checkpatch.pl:                           "Prefer
IS_ENABLED(<FOO>) to CONFIG_<FOO> || CONFIG_<FOO>_MODULE\n"
scripts/checkpatch.pl:                          $fixed[$fixlinenr] =
"\+#if IS_ENABLED($config)";





>> --- a/include/linux/kconfig.h
>> +++ b/include/linux/kconfig.h
>> @@ -31,7 +31,6 @@
>>   * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
>>   * the last step cherry picks the 2nd arg, we get a zero.
>>   */
>> -#define config_enabled(cfg)          ___is_defined(cfg)
>
> Is there a reason to keep using the double underscore prefix?



I followed the suggestion in the following message:

https://lkml.org/lkml/2016/6/6/944



>>  #define __is_defined(x)                      ___is_defined(x)
>>  #define ___is_defined(val)           ____is_defined(__ARG_PLACEHOLDER_##val)
>>  #define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0)
>
> __is_defined() is now meant to be used generally, and not just on
> kconfig macros. Can it be moved into another header?



Currently, __is_defined() is only used in two places:

include/linux/export.h
include/asm-generic/export.h

Even if we fix something like IS_ENABLED(DEBUG),
we do not have many for now,
but perhaps will it be used more widely in the future?


If so, do we need to add  IS_DEFINED() or is_defined()?

in include/linux/kconfig.h ?  or include/linux/kernel.h ?




-- 
Best Regards
Masahiro Yamada

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Paul Bolle]

[Added Nicolas.]

On Thu, 2016-10-20 at 21:06 +0900, Masahiro Yamada wrote:
> 2016-10-20 19:04 GMT+09:00 Paul Bolle <pebolle@tiscali.nl>:
> > On Sun, 2016-10-16 at 20:07 +0900, Masahiro Yamada wrote:
> > There are about a dozen instances of IS_ENABLED() that target something
> > other than a kconfig macros. Are you planning to convert those to
> > __is_defined() too?
> 
> I did not notice that, but looks like there are some to be checked.

Are you willing to do that or should I give it a try (after this patch
has landed, of course)?

> > > --- a/include/linux/kconfig.h
> > > +++ b/include/linux/kconfig.h
> > > @@ -31,7 +31,6 @@
> > >   * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
> > >   * the last step cherry picks the 2nd arg, we get a zero.
> > >   */
> > > -#define config_enabled(cfg)          ___is_defined(cfg)
> > 
> > Is there a reason to keep using the double underscore prefix?
> 
> I followed the suggestion in the following message:
> 
> https://lkml.org/lkml/2016/6/6/944

Nicolas: was there any specific reason to suggest __is_defined() and
not, say, is_defined()?

> > >  #define __is_defined(x)                      ___is_defined(x)
> > >  #define
> > > ___is_defined(val)           ____is_defined(__ARG_PLACEHOLDER_##v
> > > al)
> > >  #define ____is_defined(arg1_or_junk)
> > > __take_second_arg(arg1_or_junk 1, 0)
> > 
> > __is_defined() is now meant to be used generally, and not just on
> > kconfig macros. Can it be moved into another header?
> 
> Currently, __is_defined() is only used in two places:
> 
> include/linux/export.h
> include/asm-generic/export.h
> 
> Even if we fix something like IS_ENABLED(DEBUG),
> we do not have many for now,
> but perhaps will it be used more widely in the future?
> 
> If so, do we need to add  IS_DEFINED() or is_defined()?

Either is fine with me. I'll gladly defer to anyone with good taste in
naming things.

> in include/linux/kconfig.h ?  or include/linux/kernel.h ?

kernel.h seems to be included just about anywhere and it contains
various preprocessor macros of general utility. So that looks like a
fine candidate. Would it be a problem to put it there?

Thanks,


Paul Bolle

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Nicolas Pitre]

On Thu, 20 Oct 2016, Paul Bolle wrote:

> [Added Nicolas.]
> 
> On Thu, 2016-10-20 at 21:06 +0900, Masahiro Yamada wrote:
> > 2016-10-20 19:04 GMT+09:00 Paul Bolle <pebolle@tiscali.nl>:
> > > Is there a reason to keep using the double underscore prefix?
> > 
> > I followed the suggestion in the following message:
> > 
> > https://lkml.org/lkml/2016/6/6/944
> 
> Nicolas: was there any specific reason to suggest __is_defined() and
> not, say, is_defined()?

Not really, except maybe to keep more distance from the defined() 
preprocessor macro. But I don't have a strong opinion either ways.


Nicolas

Re: [PATCH] kconfig.h: remove config_enabled() macro

[Masahiro Yamada]

Hi Paul,


2016-10-20 21:44 GMT+09:00 Paul Bolle <pebolle@tiscali.nl>:
> [Added Nicolas.]
>
> On Thu, 2016-10-20 at 21:06 +0900, Masahiro Yamada wrote:
>> 2016-10-20 19:04 GMT+09:00 Paul Bolle <pebolle@tiscali.nl>:
>> > On Sun, 2016-10-16 at 20:07 +0900, Masahiro Yamada wrote:
>> > There are about a dozen instances of IS_ENABLED() that target something
>> > other than a kconfig macros. Are you planning to convert those to
>> > __is_defined() too?
>>
>> I did not notice that, but looks like there are some to be checked.
>
> Are you willing to do that or should I give it a try (after this patch
> has landed, of course)?


If you volunteer to do it,
that'll be appreciated.

If you CC me, I am happy to review the patches.


-- 
Best Regards
Masahiro Yamada