latest list of unused Kconfig variables

latest list of unused Kconfig variables

[Robert P. J. Day]

  now that 2.6.25-rc1 is out, i can start updating the output from my
scanning scripts.  the first updated output is the list of currently
unused Kconfig variables -- variables that are defined in some Kconfig
file somewhere but appear to be entirely unused throughout the source
tree.

  latest output here, sorted by architecture:

http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables

as always, there will probably be some false positives for one reason
or another.

  output from the other scanning scripts will be up in short order.

rday
--

========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
========================================================================

Re: latest list of unused Kconfig variables

[Paul Mundt]

On Wed, Feb 13, 2008 at 03:56:34AM -0500, Robert P. J. Day wrote:
>   latest output here, sorted by architecture:
> 
> http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> 
> as always, there will probably be some false positives for one reason
> or another.
>

>>>>> SH_SDK7780_STANDALONE
arch/sh/boards/renesas/sdk7780/Kconfig:7:config SH_SDK7780_STANDALONE

is taken care of, thanks.

Re: latest list of unused Kconfig variables

[Robert P. J. Day]

On Wed, 13 Feb 2008, Paul Mundt wrote:

> On Wed, Feb 13, 2008 at 03:56:34AM -0500, Robert P. J. Day wrote:
> >   latest output here, sorted by architecture:
> >
> > http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> >
> > as always, there will probably be some false positives for one reason
> > or another.
> >
>
> >>>>> SH_SDK7780_STANDALONE
> arch/sh/boards/renesas/sdk7780/Kconfig:7:config SH_SDK7780_STANDALONE
>
> is taken care of, thanks.

ok, i tossed it from the list.

rday
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
========================================================================

Re: latest list of unused Kconfig variables

[Josh Boyer]

On Wed, 13 Feb 2008 03:56:34 -0500 (EST)
"Robert P. J. Day" <rpjday@crashcourse.ca> wrote:

> 
>   now that 2.6.25-rc1 is out, i can start updating the output from my
> scanning scripts.  the first updated output is the list of currently
> unused Kconfig variables -- variables that are defined in some Kconfig
> file somewhere but appear to be entirely unused throughout the source
> tree.
> 
>   latest output here, sorted by architecture:
> 
> http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> 
> as always, there will probably be some false positives for one reason
> or another.
> 
>   output from the other scanning scripts will be up in short order.

You have lots of false positives (or something) for arch/powerpc.  Seems
your script picked up #define names and comments that happen to match a
Kconfig variable?  And you have false positives on several CPU
variables, as they are used within Kconfig files themselves to select
different sets of options.

For arch/ppc, the WANT_EARLY_SERIAL stuff was added by Al to fix those
boards that unconditionally called early_serial_setup by selecting
SERIAL_8250 in commit f08243a491f3e21feabbb04476a03fb0cbc975ff.  Al,
couldn't we just select SERIAL_8250 right in the board config
instead?  

Of course, arch/ppc is dying soon-ish anyway so we might not even
bother.

josh

Re: latest list of unused Kconfig variables

[Robert P. J. Day]

On Wed, 13 Feb 2008, Josh Boyer wrote:

> On Wed, 13 Feb 2008 03:56:34 -0500 (EST)
> "Robert P. J. Day" <rpjday@crashcourse.ca> wrote:

> >   now that 2.6.25-rc1 is out, i can start updating the output from
> > my scanning scripts.  the first updated output is the list of
> > currently unused Kconfig variables -- variables that are defined
> > in some Kconfig file somewhere but appear to be entirely unused
> > throughout the source tree.
> >
> >   latest output here, sorted by architecture:
> >
> > http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> >
> > as always, there will probably be some false positives for one
> > reason or another.
> >
> >   output from the other scanning scripts will be up in short order.
>
> You have lots of false positives (or something) for arch/powerpc.
> Seems your script picked up #define names and comments that happen
> to match a Kconfig variable?

it always will, given the proclivity of some folks to define their own
variables with a "CONFIG_" prefix.  as i point out on the wiki page, i
make no attempt to cull that list, i just print it as is, and readers
will have to peruse the list carefully to see what's meaningful and
what isn't.

> And you have false positives on several CPU variables, as they are
> used within Kconfig files themselves to select different sets of
> options.

yes, i know ... perhaps there's a simple way to filter those out but,
at the moment, it's pure brute force.  i'm guessing i could make that
script a bit smarter but it probably isn't worth the investment in
time.  law of diminishing returns and all that.

> For arch/ppc, the WANT_EARLY_SERIAL stuff was added by Al to fix those
> boards that unconditionally called early_serial_setup by selecting
> SERIAL_8250 in commit f08243a491f3e21feabbb04476a03fb0cbc975ff.  Al,
> couldn't we just select SERIAL_8250 right in the board config
> instead?
>
> Of course, arch/ppc is dying soon-ish anyway so we might not even
> bother.

if that's the case, i can just stop scanning that entire directory.

rday
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
========================================================================

Re: latest list of unused Kconfig variables

[Sam Ravnborg]

On Wed, Feb 13, 2008 at 10:07:27AM -0500, Robert P. J. Day wrote:
> On Wed, 13 Feb 2008, Josh Boyer wrote:
> 
> > On Wed, 13 Feb 2008 03:56:34 -0500 (EST)
> > "Robert P. J. Day" <rpjday@crashcourse.ca> wrote:
> 
> > >   now that 2.6.25-rc1 is out, i can start updating the output from
> > > my scanning scripts.  the first updated output is the list of
> > > currently unused Kconfig variables -- variables that are defined
> > > in some Kconfig file somewhere but appear to be entirely unused
> > > throughout the source tree.
> > >
> > >   latest output here, sorted by architecture:
> > >
> > > http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> > >
> > > as always, there will probably be some false positives for one
> > > reason or another.
> > >
> > >   output from the other scanning scripts will be up in short order.
> >
> > You have lots of false positives (or something) for arch/powerpc.
> > Seems your script picked up #define names and comments that happen
> > to match a Kconfig variable?
> 
> it always will, given the proclivity of some folks to define their own
> variables with a "CONFIG_" prefix.  as i point out on the wiki page, i
> make no attempt to cull that list, i just print it as is, and readers
> will have to peruse the list carefully to see what's meaningful and
> what isn't.

CONFIG_* should in the kernel be assumed a reserved namespace for kconifg.
So any use of variables/defines named CONFIG_* which is not a kconfig
symbol is a bug.

	Sam

Re: latest list of unused Kconfig variables

[Robert P. J. Day]

On Wed, 13 Feb 2008, Sam Ravnborg wrote:

> On Wed, Feb 13, 2008 at 10:07:27AM -0500, Robert P. J. Day wrote:
> > On Wed, 13 Feb 2008, Josh Boyer wrote:
> >
> > > On Wed, 13 Feb 2008 03:56:34 -0500 (EST)
> > > "Robert P. J. Day" <rpjday@crashcourse.ca> wrote:
> >
> > > >   now that 2.6.25-rc1 is out, i can start updating the output from
> > > > my scanning scripts.  the first updated output is the list of
> > > > currently unused Kconfig variables -- variables that are defined
> > > > in some Kconfig file somewhere but appear to be entirely unused
> > > > throughout the source tree.
> > > >
> > > >   latest output here, sorted by architecture:
> > > >
> > > > http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> > > >
> > > > as always, there will probably be some false positives for one
> > > > reason or another.
> > > >
> > > >   output from the other scanning scripts will be up in short order.
> > >
> > > You have lots of false positives (or something) for arch/powerpc.
> > > Seems your script picked up #define names and comments that happen
> > > to match a Kconfig variable?
> >
> > it always will, given the proclivity of some folks to define their own
> > variables with a "CONFIG_" prefix.  as i point out on the wiki page, i
> > make no attempt to cull that list, i just print it as is, and readers
> > will have to peruse the list carefully to see what's meaningful and
> > what isn't.
>
> CONFIG_* should in the kernel be assumed a reserved namespace for
> kconifg. So any use of variables/defines named CONFIG_* which is not
> a kconfig symbol is a bug.

heh ... good luck with *that*:

$ grep -r "^#define CONFIG_" * | wc -l
752
$

rday
--

========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
========================================================================

Re: latest list of unused Kconfig variables

[Josh Boyer]

On Wed, 13 Feb 2008 10:07:27 -0500 (EST)
"Robert P. J. Day" <rpjday@crashcourse.ca> wrote:

> On Wed, 13 Feb 2008, Josh Boyer wrote:
> 
> > On Wed, 13 Feb 2008 03:56:34 -0500 (EST)
> > "Robert P. J. Day" <rpjday@crashcourse.ca> wrote:
> 
> > >   now that 2.6.25-rc1 is out, i can start updating the output from
> > > my scanning scripts.  the first updated output is the list of
> > > currently unused Kconfig variables -- variables that are defined
> > > in some Kconfig file somewhere but appear to be entirely unused
> > > throughout the source tree.
> > >
> > >   latest output here, sorted by architecture:
> > >
> > > http://www.crashcourse.ca/wiki/index.php/Unused_CONFIG_variables
> > >
> > > as always, there will probably be some false positives for one
> > > reason or another.
> > >
> > >   output from the other scanning scripts will be up in short order.
> >
> > You have lots of false positives (or something) for arch/powerpc.
> > Seems your script picked up #define names and comments that happen
> > to match a Kconfig variable?
> 
> it always will, given the proclivity of some folks to define their own
> variables with a "CONFIG_" prefix.  as i point out on the wiki page, i
> make no attempt to cull that list, i just print it as is, and readers
> will have to peruse the list carefully to see what's meaningful and
> what isn't.

OK.  Well all of your hits for 405EX, 440GRX, 440SPe, and
WANT_DEVICE_TREE in arch/powerpc seem bogus.  I dunno if you prune
those when reported or not.

> > And you have false positives on several CPU variables, as they are
> > used within Kconfig files themselves to select different sets of
> > options.
> 
> yes, i know ... perhaps there's a simple way to filter those out but,
> at the moment, it's pure brute force.  i'm guessing i could make that
> script a bit smarter but it probably isn't worth the investment in
> time.  law of diminishing returns and all that.

Maybe.  If the same false positives keep showing up people might ignore
it.  I won't, but others might.

> > For arch/ppc, the WANT_EARLY_SERIAL stuff was added by Al to fix those
> > boards that unconditionally called early_serial_setup by selecting
> > SERIAL_8250 in commit f08243a491f3e21feabbb04476a03fb0cbc975ff.  Al,
> > couldn't we just select SERIAL_8250 right in the board config
> > instead?
> >
> > Of course, arch/ppc is dying soon-ish anyway so we might not even
> > bother.
> 
> if that's the case, i can just stop scanning that entire directory.

It's going away in June, per feature-removal-schedule.  I will still fix
actual bugs until then, but not much else.

josh

Re: latest list of unused Kconfig variables

[Robert P. J. Day]

On Wed, 13 Feb 2008, Josh Boyer wrote:

> OK.  Well all of your hits for 405EX, 440GRX, 440SPe, and
> WANT_DEVICE_TREE in arch/powerpc seem bogus.  I dunno if you prune
> those when reported or not.

not normally, but i don't know what you mean by "bogus":

  $ grep -r "config 405EX" *
  arch/powerpc/platforms/40x/Kconfig:config 405EX
  $

  $ grep -r CONFIG_405EX *
  arch/powerpc/configs/makalu_defconfig:CONFIG_405EX=y
  arch/powerpc/configs/kilauea_defconfig:CONFIG_405EX=y
  $

so, AFAICT, there exists a definition of the Kconfig variable 405EX,
which is subsequently not referenced *anywhere* in the tree except in
a couple defconfig files, which don't count.  how, then, does that
Kconfig variable have any practical value?  or am i missing something
painfully obvious?

> > > And you have false positives on several CPU variables, as they
> > > are used within Kconfig files themselves to select different
> > > sets of options.
> >
> > yes, i know ... perhaps there's a simple way to filter those out
> > but, at the moment, it's pure brute force.  i'm guessing i could
> > make that script a bit smarter but it probably isn't worth the
> > investment in time.  law of diminishing returns and all that.
>
> Maybe.  If the same false positives keep showing up people might
> ignore it.  I won't, but others might.

fair enough, but since this scanning happens only once every release,
it's not like it's a burden.  and if people want to ignore it, that's
fine, too.

rday
--

========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
========================================================================

Re: latest list of unused Kconfig variables

[Sam Ravnborg]

On Wed, Feb 13, 2008 at 10:44:27AM -0500, Robert P. J. Day wrote:
> On Wed, 13 Feb 2008, Josh Boyer wrote:
> 
> > OK.  Well all of your hits for 405EX, 440GRX, 440SPe, and
> > WANT_DEVICE_TREE in arch/powerpc seem bogus.  I dunno if you prune
> > those when reported or not.
> 
> not normally, but i don't know what you mean by "bogus":
> 
>   $ grep -r "config 405EX" *
>   arch/powerpc/platforms/40x/Kconfig:config 405EX
>   $
> 
>   $ grep -r CONFIG_405EX *
>   arch/powerpc/configs/makalu_defconfig:CONFIG_405EX=y
>   arch/powerpc/configs/kilauea_defconfig:CONFIG_405EX=y
>   $

$ git grep 405EX | grep select
arch/powerpc/platforms/40x/Kconfig:     select 405EX
arch/powerpc/platforms/40x/Kconfig:     select 405EX

So it is used.

	Sam

Re: latest list of unused Kconfig variables

[Robert P. J. Day]

On Wed, 13 Feb 2008, Sam Ravnborg wrote:

> On Wed, Feb 13, 2008 at 10:44:27AM -0500, Robert P. J. Day wrote:
> > On Wed, 13 Feb 2008, Josh Boyer wrote:
> >
> > > OK.  Well all of your hits for 405EX, 440GRX, 440SPe, and
> > > WANT_DEVICE_TREE in arch/powerpc seem bogus.  I dunno if you prune
> > > those when reported or not.
> >
> > not normally, but i don't know what you mean by "bogus":
> >
> >   $ grep -r "config 405EX" *
> >   arch/powerpc/platforms/40x/Kconfig:config 405EX
> >   $
> >
> >   $ grep -r CONFIG_405EX *
> >   arch/powerpc/configs/makalu_defconfig:CONFIG_405EX=y
> >   arch/powerpc/configs/kilauea_defconfig:CONFIG_405EX=y
> >   $
>
> $ git grep 405EX | grep select
> arch/powerpc/platforms/40x/Kconfig:     select 405EX
> arch/powerpc/platforms/40x/Kconfig:     select 405EX
>
> So it is used.

ok, i see the flaw in my logic.  the Kconfig variable 405EX isn't
tested *directly* by anyone, it's simply used to further "select"
other variables, which my script doesn't take into account.

  config 405EX
        bool
        select IBM_NEW_EMAC_EMAC4
        select IBM_NEW_EMAC_RGMII

i don't think i'm quite ready to add that logic to a simple scanning
script.

oh, well.

rday
--

========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
========================================================================