Re: [linux-next:master 3345/4062] include/linux/highmem-internal.h:203:31: error: passing argument 1 of 'kunmap_flush_on_unmap' discards 'const' qualifier from pointer target type

[David Sterba <dsterba@suse.cz>]

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On Thu, Jun 16, 2022 at 04:58:08PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   c6d7e3b385f19869ab96e9404c92ff1abc34f2c8
> commit: 20adc3e8f39ad4ce68795b6d3f9847f45ccd931a [3345/4062] highmem: Make kunmap_{local,atomic}() take pointers to const void
> config: parisc-randconfig-r012-20220616 (https://download.01.org/0day-ci/archive/20220616/202206161652.aEEuklTk-lkp(a)intel.com/config)
> compiler: hppa-linux-gcc (GCC) 11.3.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=20adc3e8f39ad4ce68795b6d3f9847f45ccd931a
>         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>         git fetch --no-tags linux-next master
>         git checkout 20adc3e8f39ad4ce68795b6d3f9847f45ccd931a
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=parisc SHELL=/bin/bash drivers/iio/light/ drivers/net/wwan/t7xx/
> 
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All error/warnings (new ones prefixed by >>):
> 
>    In file included from include/linux/highmem.h:13,
>                     from include/linux/bvec.h:10,
>                     from include/linux/blk_types.h:10,
>                     from include/linux/writeback.h:13,
>                     from include/linux/memcontrol.h:22,
>                     from include/linux/swap.h:9,
>                     from include/linux/suspend.h:5,
>                     from include/linux/regulator/consumer.h:35,
>                     from include/linux/i2c.h:19,
>                     from drivers/iio/light/adjd_s311.c:15:
>    include/linux/highmem-internal.h: In function '__kunmap_local':
> >> include/linux/highmem-internal.h:203:31: warning: passing argument 1 of 'kunmap_flush_on_unmap' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
>      203 |         kunmap_flush_on_unmap(addr);

I think you missed adding const to kunmap_flush_on_unmap, in some
configs it could be hidden behind an ifdef. The warning is on
ARCH=parisc,

https://elixir.bootlin.com/linux/latest/source/arch/parisc/include/asm/cacheflush.h#L78

	#define ARCH_HAS_FLUSH_ON_KUNMAP
	static inline void kunmap_flush_on_unmap(void *addr)
	{
		flush_kernel_dcache_page_addr(addr);
	}