linux-kernel - reasonable for a Kconfig variable to be tested only for "

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Date:	Thu, 12 Apr 2012 07:30:42 -0400 (EDT)
From:	"Robert P. J. Day" <rpjday@...shcourse.ca>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: reasonable for a Kconfig variable to be tested only for "_MODULE"?


  playing with my cleanup scripts this morning and ran across this
output looking for unused CONFIG_ variables under drivers/ata:

$ ../s/find_unused_configs.sh drivers/ata
===== PATA_QDI
drivers/ata/Kconfig:831:config PATA_QDI
===== PATA_WINBOND_VLB
drivers/ata/Kconfig:865:config PATA_WINBOND_VLB
$

  normally, i would flag that as "variables that are defined in a
Kconfig file but are never tested anywhere", but upon further
examination:

$ $ grep -r PATA_QDI *
drivers/ata/Kconfig:config PATA_QDI
drivers/ata/pata_legacy.c:#ifdef CONFIG_PATA_QDI_MODULE
$

so "CONFIG_PATA_QDI" isn't tested, but "CONFIG_PATA_QDI_MODULE" *is*,
which is not something i'd considered.  the Kconfig entry:

config PATA_QDI
        tristate "QDI VLB PATA support"
        depends on ISA
        select PATA_LEGACY
        help
          Support for QDI 6500 and 6580 PATA controllers on VESA local bus.

and the relevant source:

/* Set to probe QDI controllers */
#ifdef CONFIG_PATA_QDI_MODULE
static int qdi = 1;
#else
static int qdi;
#endif

  is that combination reasonable?  to test *only* for
"CONFIG_whatever_MODULE"?  if it is, i'll add that check to avoid
reporting false positives.

  all of the above can be said for PATA_WINBOND_VLB as well.

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================


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