[Kernel-janitors] [rfc] a lot of unused CONFIG_*

[Kernel-janitors] [rfc] a lot of unused CONFIG_*

[Domen Puncer]

Hi.

# wc -l CONFIG_defined_but_not_used CONFIG_not_defined_but_used
    116 CONFIG_defined_but_not_used
    635 CONFIG_not_defined_but_used

This is a lot!

I didn't strip out "*_MODULE" (don't know if they're automagicaly
generated and it doesn't make much difference).

So... am I wrong about my script, or do we have A LOT of work to do?

Any suggestions, how to fix this? (grepping for every symbol, and
replacing it takes too much time).


Upper 2 files were generated from following commands in bash.
Sorry, not very readable, i know.
# these executed on kernel source
# find files that use *CONFIG_*
find | egrep '\.[chS]$' | xargs egrep 'CONFIG_[A-Z0-9a-z]*' | sed 's/.*CONFIG_/CONFIG_/g' | sed 's/[^A-Z0-9a-z_].*//' | sort | uniq | tee ../CONFIGs_in_source

# find CONFIG_* that are defined in Kconfig files
find | grep Kconfig | xargs egrep '^config.*[A-Z0-9a-z_]+$' | sed 's/.*config[^A-Z0-9a-z_]*/CONFIG_/g' | sort | uniq | tee ../config

# find *CONFIG_* defined in sources
find | egrep '\.[chS]$' | xargs egrep '#define.*CONFIG' | sed 's/.*CONFIG_/CONFIG_/g' | sed 's/[^A-Z0-9a-z_].*//' | sort | uniq | tee ../CONFIGs_defined

# these on ".." relative to kernel source
# used (or defined) in sources, but not defined in Kconfig
diff CONFIGs_in_source config | egrep '^<' | cut -f2 -d\  > CONFIGs_not_in_config

# filename says it all
diff CONFIGs_not_in_config CONFIGs_defined | grep '<' | cut -f2 -d\  > CONFIG_not_defined_but_used

# see filename
diff CONFIGs_not_in_config CONFIGs_defined | grep '>' | cut -f2 -d\  > CONFIG_defined_but_not_used

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Re: [Kernel-janitors] [rfc] a lot of unused CONFIG_*

[Adrian Bunk]

On Sat, Jan 17, 2004 at 05:04:40PM +0100, Domen Puncer wrote:
> Hi.
> 
> # wc -l CONFIG_defined_but_not_used CONFIG_not_defined_but_used
>     116 CONFIG_defined_but_not_used
>     635 CONFIG_not_defined_but_used
> 
> This is a lot!
> 
> I didn't strip out "*_MODULE" (don't know if they're automagicaly
> generated and it doesn't make much difference).

These symbols are automatically generated when configuring a variable to 
be modular.

> So... am I wrong about my script, or do we have A LOT of work to do?
>...

It's sometimes used and 100% correct to define options that are only 
used in the Kconfig file they are defined in.
Examples are some cpu variables in from arch/i386/Kconfig .

It often occurs that a variable is only used in a Makefile to select a 
subdirectory (e.g. CONFIG_E1000), but your scripts didn't count this 
use.

Not all Kconfig files are named Kconfig, Kconfig\* is a better 
expression.

Not all things your script output are really bugs, e.g. there might be 
an #ifdef CONFIG_FOO in the code without CONFIG_FOO being defined 
anywhere, but it's defined in another tree (e.g. an architecture tree) 
that will be resynced with the kernel soon.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

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Re: [Kernel-janitors] [rfc] a lot of unused CONFIG_*

[Randy.Dunlap]

On Sun, 18 Jan 2004 13:53:22 +0100 Adrian Bunk <bunk@fs.tum.de> wrote:

| On Sat, Jan 17, 2004 at 05:04:40PM +0100, Domen Puncer wrote:
| > Hi.
| > 
| > # wc -l CONFIG_defined_but_not_used CONFIG_not_defined_but_used
| >     116 CONFIG_defined_but_not_used
| >     635 CONFIG_not_defined_but_used
| > 
| > This is a lot!
| > 
| > I didn't strip out "*_MODULE" (don't know if they're automagicaly
| > generated and it doesn't make much difference).
| 
| These symbols are automatically generated when configuring a variable to 
| be modular.
| 
| > So... am I wrong about my script, or do we have A LOT of work to do?
| >...
| 
| It's sometimes used and 100% correct to define options that are only 
| used in the Kconfig file they are defined in.
| Examples are some cpu variables in from arch/i386/Kconfig .
| 
| It often occurs that a variable is only used in a Makefile to select a 
| subdirectory (e.g. CONFIG_E1000), but your scripts didn't count this 
| use.
| 
| Not all Kconfig files are named Kconfig, Kconfig\* is a better 
| expression.
| 
| Not all things your script output are really bugs, e.g. there might be 
| an #ifdef CONFIG_FOO in the code without CONFIG_FOO being defined 
| anywhere, but it's defined in another tree (e.g. an architecture tree) 
| that will be resynced with the kernel soon.

Summary:  the script is too (mechanical|simple).
It may be used for hints/help.
Take them on a case-by-case basis.

--
~Randy
Everything is relative.
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