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

[Fabio M. De Francesco <fmdefrancesco@gmail.com>]

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On giovedì 16 giugno 2022 15:12:43 CEST David Sterba wrote:
> 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);
> 	}
> 
> 
I think that you are looking at an old report. Hours ago I sent a new 
version of this patch[1] and also a new version of the patch for the 
conversions of zstd.c to kmap_local_page() (without those casts which are 
no any longer necessary).

Sorry for not replying to this report.

Thanks,

Fabio

[1] https://lore.kernel.org/lkml/20220616081133.14144-2-fmdefrancesco(a)gmail.com/

[2] https://lore.kernel.org/lkml/20220616081133.14144-3-fmdefrancesco(a)gmail.com/