Re: [akpm-mm:mm-unstable 93/173] drivers/clk/clk-fixed-mmio.c:33:2: error: call to undeclared function 'iounmap'; ISO C99 and later do not support implicit function declarations

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 13 Jul 2023 10:57:34 +0800 kernel test robot <lkp@intel.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> head:   e726c62e70a70ae5536caa0aa131c5dce5c6f764
> commit: 827057ff3ce7554741d431145c3b93f1a54125fc [93/173] s390: mm: convert to GENERIC_IOREMAP
> config: s390-randconfig-r033-20230713 (https://download.01.org/0day-ci/archive/20230713/202307131033.JgvCSVz4-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
> reproduce: (https://download.01.org/0day-ci/archive/20230713/202307131033.JgvCSVz4-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202307131033.JgvCSVz4-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from drivers/clk/clk-fixed-mmio.c:13:
>    In file included from include/linux/io.h:13:
>    In file included from arch/s390/include/asm/io.h:78:
>    include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>      547 |         val = __raw_readb(PCI_IOBASE + addr);
>          |                           ~~~~~~~~~~ ^

Thanks.  When I tried that config I got

In file included from ./include/linux/io.h:13,
                 from drivers/clk/clk-fixed-mmio.c:13:
drivers/clk/clk-fixed-mmio.c: In function 'fixed_mmio_clk_setup':
./arch/s390/include/asm/io.h:29:17: error: implicit declaration of function 'iounmap'; did you mean 'vunmap'? [-Werror=implicit-function-declaration]
   29 | #define iounmap iounmap
      |                 ^~~~~~~
drivers/clk/clk-fixed-mmio.c:33:9: note: in expansion of macro 'iounmap'
   33 |         iounmap(base);
      |         ^~~~~~~

I'll drop the series.