Re: [PATCH] kbuild: move -Wunused-const-variable to W=1 warning level

[Michal Marek]

On Tue, May 10, 2016 at 11:30:01PM +0200, Arnd Bergmann wrote:
> gcc-6 started warning by default about variables that are not
> used anywhere and that are marked 'const', generating many
> false positives in an allmodconfig build, e.g.:
> 
> arch/arm/mach-davinci/board-da830-evm.c:282:20: warning: 'da830_evm_emif25_pins' defined but not used [-Wunused-const-variable=]
> arch/arm/plat-omap/dmtimer.c:958:34: warning: 'omap_timer_match' defined but not used [-Wunused-const-variable=]
> drivers/bluetooth/hci_bcm.c:625:39: warning: 'acpi_bcm_default_gpios' defined but not used [-Wunused-const-variable=]
> drivers/char/hw_random/omap-rng.c:92:18: warning: 'reg_map_omap4' defined but not used [-Wunused-const-variable=]
> drivers/devfreq/exynos/exynos5_bus.c:381:32: warning: 'exynos5_busfreq_int_pm' defined but not used [-Wunused-const-variable=]
> drivers/dma/mv_xor.c:1139:34: warning: 'mv_xor_dt_ids' defined but not used [-Wunused-const-variable=]
> 
> This is similar to the existing -Wunused-but-set-variable warning
> that was added in an earlier release and that we disable by default
> now and only enable when W=1 is set, so it makes sense to do
> the same here. Once we have eliminated the majority of the
> warnings for both, we can put them back into the default list.
> 
> We probably want this in backport kernels as well, to allow building
> them with gcc-6 without introducing extra warnings.
> 
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Applied to kbuild.git#kbuild.

Michal