2022-06-28 10:44:57

by Peter Zijlstra

[permalink] [raw]
Subject: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co


Since IS_ENABLED() (and friends) are clearly meant to be used on
CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
tautology, allow the more compact usage of: IS_ENABLED(foo).

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
---

With this on, something like:

for i in IS_BUILTIN IS_MODULE IS_REACHABLE IS_ENABLED;
do
git grep -wl $i | while read file;
do
sed -ie "s/${i}(CONFIG_/${i}(/g" $file;
done;
done

can be used to convert all existing instance. Allowing, after time
passes, to remove the CONFIG_ usage if so desired.

---
tools/include/linux/kconfig.h | 7 ++++---
include/linux/kconfig.h | 7 ++++---
2 files changed, 8 insertions(+), 6 deletions(-)

--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -38,6 +38,7 @@
* 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 _is_defined(x) __or(__is_defined(x), __is_defined(CONFIG_##x))
#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)
@@ -47,14 +48,14 @@
* otherwise. For boolean options, this is equivalent to
* IS_ENABLED(CONFIG_FOO).
*/
-#define IS_BUILTIN(option) __is_defined(option)
+#define IS_BUILTIN(option) _is_defined(option)

/*
* IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
* otherwise. CONFIG_FOO=m results in "#define CONFIG_FOO_MODULE 1" in
* autoconf.h.
*/
-#define IS_MODULE(option) __is_defined(option##_MODULE)
+#define IS_MODULE(option) _is_defined(option##_MODULE)

/*
* IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled
@@ -63,7 +64,7 @@
* built-in code when CONFIG_FOO is set to 'm'.
*/
#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
- __and(IS_MODULE(option), __is_defined(MODULE)))
+ __and(IS_MODULE(option), _is_defined(MODULE)))

/*
* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
--- a/tools/include/linux/kconfig.h
+++ b/tools/include/linux/kconfig.h
@@ -32,6 +32,7 @@
* 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 _is_defined(x) __or(__is_defined(x), __is_defined(CONFIG_##x))
#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 +42,13 @@
* otherwise. For boolean options, this is equivalent to
* IS_ENABLED(CONFIG_FOO).
*/
-#define IS_BUILTIN(option) __is_defined(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) __is_defined(option##_MODULE)
+#define IS_MODULE(option) _is_defined(option##_MODULE)

/*
* IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled
@@ -56,7 +57,7 @@
* built-in code when CONFIG_FOO is set to 'm'.
*/
#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
- __and(IS_MODULE(option), __is_defined(MODULE)))
+ __and(IS_MODULE(option), _is_defined(MODULE)))

/*
* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',


2022-06-28 11:29:37

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co

On Tue, Jun 28, 2022 at 11:56 AM Peter Zijlstra <[email protected]> wrote:
>
> Since IS_ENABLED() (and friends) are clearly meant to be used on
> CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
> tautology, allow the more compact usage of: IS_ENABLED(foo).
>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>

I'd prefer to keep the more verbose usage, mainly because it makes it easier
to grep for a symbol. If today you do 'git grep CONFIG_PM_SLEEP', you find
all instances in Makefile, in #ifdef and in IS_ENABLED(), though not the
references in Kconfig language, which leave out the prefix.

If we remove the prefix for IS_ENABLED(), the same grep fails to get
all the results, while searching for the substring without the CONFIG_
prefix can end up finding false-positives by finding longer strings (e.g.
CONFIG_DEBUG_STACKOVERFLOW vs
CONFIG_HAVE_DEBUG_STACKOVERFLOW).

Arnd

2022-06-28 12:19:15

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co

On Tue, Jun 28, 2022 at 01:19:17PM +0200, Arnd Bergmann wrote:
> On Tue, Jun 28, 2022 at 11:56 AM Peter Zijlstra <[email protected]> wrote:
> >
> > Since IS_ENABLED() (and friends) are clearly meant to be used on
> > CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
> > tautology, allow the more compact usage of: IS_ENABLED(foo).
> >
> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
>
> I'd prefer to keep the more verbose usage, mainly because it makes it easier
> to grep for a symbol. If today you do 'git grep CONFIG_PM_SLEEP', you find
> all instances in Makefile, in #ifdef and in IS_ENABLED(), though not the
> references in Kconfig language, which leave out the prefix.

Which is why I never grep for the CONFIG_ thing to begin with, it misses
the Kconfig site.

> If we remove the prefix for IS_ENABLED(), the same grep fails to get
> all the results, while searching for the substring without the CONFIG_
> prefix can end up finding false-positives by finding longer strings (e.g.
> CONFIG_DEBUG_STACKOVERFLOW vs
> CONFIG_HAVE_DEBUG_STACKOVERFLOW).

Me being used to that doesn't consider that a real issue :-) I'd much
rather have the somewhat shorter IS_ENABLED() things.

2022-06-28 12:24:31

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co

On Tue, Jun 28, 2022 at 9:02 PM Peter Zijlstra <[email protected]> wrote:
>
> On Tue, Jun 28, 2022 at 01:19:17PM +0200, Arnd Bergmann wrote:
> > On Tue, Jun 28, 2022 at 11:56 AM Peter Zijlstra <[email protected]> wrote:
> > >
> > > Since IS_ENABLED() (and friends) are clearly meant to be used on
> > > CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
> > > tautology, allow the more compact usage of: IS_ENABLED(foo).
> > >
> > > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> >
> > I'd prefer to keep the more verbose usage, mainly because it makes it easier
> > to grep for a symbol. If today you do 'git grep CONFIG_PM_SLEEP', you find
> > all instances in Makefile, in #ifdef and in IS_ENABLED(), though not the
> > references in Kconfig language, which leave out the prefix.
>
> Which is why I never grep for the CONFIG_ thing to begin with, it misses
> the Kconfig site.
>
> > If we remove the prefix for IS_ENABLED(), the same grep fails to get
> > all the results, while searching for the substring without the CONFIG_
> > prefix can end up finding false-positives by finding longer strings (e.g.
> > CONFIG_DEBUG_STACKOVERFLOW vs
> > CONFIG_HAVE_DEBUG_STACKOVERFLOW).
>
> Me being used to that doesn't consider that a real issue :-) I'd much
> rather have the somewhat shorter IS_ENABLED() things.




One more thing worth mentioning, this patch does
not even work correctly.


scripts/basic/fixdep.c searches for CONFIG_ prefix.
This works nicely, and there is no reason to lose this simplicity.


NACK.

--
Best Regards
Masahiro Yamada

2022-06-28 12:25:23

by Rasmus Villemoes

[permalink] [raw]
Subject: Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co

On 28/06/2022 13.19, Arnd Bergmann wrote:
> On Tue, Jun 28, 2022 at 11:56 AM Peter Zijlstra <[email protected]> wrote:
>>
>> Since IS_ENABLED() (and friends) are clearly meant to be used on
>> CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
>> tautology, allow the more compact usage of: IS_ENABLED(foo).
>>
>> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
>
> I'd prefer to keep the more verbose usage, mainly because it makes it easier
> to grep for a symbol. If today you do 'git grep CONFIG_PM_SLEEP', you find
> all instances in Makefile, in #ifdef and in IS_ENABLED(), though not the
> references in Kconfig language, which leave out the prefix.

Agreed.

Also, having CONFIG_ added implicitly requires updating fixdep, and that
will probably make the fixdep step somewhat more expensive - because one
would still have to find all explicit CONFIG_SOMETHING (they'd still be
used in ifdefs, and the int and string options directly in code), but in
addition also grep for IS_ENABLED, IS_BUILTIN, IS_MODULE.

Rasmus

2022-06-28 14:32:02

by Paul Gortmaker

[permalink] [raw]
Subject: Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co

[Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co] On 28/06/2022 (Tue 13:19) Arnd Bergmann wrote:

> On Tue, Jun 28, 2022 at 11:56 AM Peter Zijlstra <[email protected]> wrote:
> >
> > Since IS_ENABLED() (and friends) are clearly meant to be used on
> > CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
> > tautology, allow the more compact usage of: IS_ENABLED(foo).
> >
> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
>
> I'd prefer to keep the more verbose usage, mainly because it makes it easier
> to grep for a symbol. If today you do 'git grep CONFIG_PM_SLEEP', you find
> all instances in Makefile, in #ifdef and in IS_ENABLED(), though not the
> references in Kconfig language, which leave out the prefix.

TL;DR - me too.

I confess that I do the same thing - I grep for CONFIG_FOO to find the
consumers, and "config FOO" to find the provider.

So while I can appreciate the value of removing verbosity, this will
impact workflows of average people out there.

Doing a grep for "PCI" is practically worthless. Having to grep for
both CONFIG_PCI and IS_ENABLED\(PCI will inevitably annoy people when
they realize they missed a code path needing an update because they only
searched for the former.

Paul.
--

>
> If we remove the prefix for IS_ENABLED(), the same grep fails to get
> all the results, while searching for the substring without the CONFIG_
> prefix can end up finding false-positives by finding longer strings (e.g.
> CONFIG_DEBUG_STACKOVERFLOW vs
> CONFIG_HAVE_DEBUG_STACKOVERFLOW).
>
> Arnd

2022-06-29 15:11:55

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [RFC][PATCH] kconfig: Add implicit CONFIG_ prefix to IS_ENABLED() and co

On Tue, Jun 28, 2022 at 11:56:10AM +0200, Peter Zijlstra wrote:
>
> Since IS_ENABLED() (and friends) are clearly meant to be used on
> CONFIG_foo symbols and IS_ENABLED(CONFIG_ is so long and almost an
> tautology, allow the more compact usage of: IS_ENABLED(foo).

Eww. Please don't mess up grepability for saving a few characters
of typing.