Re: [PATCH] kconfig: Use macros which are already defined

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 23 Feb 2015 11:23:14 +0100 Michal Simek <monstr@monstr.eu> wrote:

> Hi Andrew,
> 
> On 12/11/2014 10:00 AM, Michal Simek wrote:
> > It is better to use macros which are already available
> > because then there is just one location which needs to be change.
> > 
> > Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> > ---
> > 
> > FYI: Fengguang's testing system doesn't show any build error.
> > ---
> >  include/linux/kconfig.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
> > index be342b94c640..71acdf650e2e 100644
> > --- a/include/linux/kconfig.h
> > +++ b/include/linux/kconfig.h
> > @@ -28,7 +28,7 @@
> >   *
> >   */
> >  #define IS_ENABLED(option) \
> > -	(config_enabled(option) || config_enabled(option##_MODULE))
> > +	(IS_BUILTIN(option) || IS_MODULE(option))
> > 
> >  /*
> >   * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
> > --
> > 1.8.2.3
> > 
> 

I can't find the original email anywhere, hrm.

As I received it, this patch is From:monstr@monstr.eu and
Signed-off-by:michal.simek@xilinx.com, which is unusual.  Probably you
should be adding explicit From: lines to the patch changelogs to
override this.

After the patch, IS_ENABLED is defined before the macros which it uses.
That's not an error (unless someone puts an inlined function in there
before the IS_BUILTIN or IS_MODULE definitions), but it's unusual,
unexpected and illogical.  So,

--- a/include/linux/kconfig.h~kconfig-use-macros-which-are-already-defined-fix
+++ a/include/linux/kconfig.h
@@ -23,14 +23,6 @@
 #define ___config_enabled(__ignored, val, ...) val
 
 /*
- * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
- * 0 otherwise.
- *
- */
-#define IS_ENABLED(option) \
-	(IS_BUILTIN(option) || IS_MODULE(option))
-
-/*
  * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
  * otherwise. For boolean options, this is equivalent to
  * IS_ENABLED(CONFIG_FOO).
@@ -43,4 +35,11 @@
  */
 #define IS_MODULE(option) config_enabled(option##_MODULE)
 
+/*
+ * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
+ * 0 otherwise.
+ */
+#define IS_ENABLED(option) \
+	(IS_BUILTIN(option) || IS_MODULE(option))
+
 #endif /* __LINUX_KCONFIG_H */
_