Re: [kbuild-all] Re: mm/khugepaged.c:2046:56: warning: 'struct khugepaged_mm_slot' declared inside parameter list will not be visible outside of this definition or declaration

[Chen, Rong A]

On 9/2/2022 11:37 PM, Qi Zheng wrote:
> On 2022/9/2 22:23, kernel test robot wrote:
> > tree:   
> > https://github.com/intel-lab-lkp/linux/commits/UPDATE-20220901-154717/Qi-Zheng/add-common-struct-mm_slot-and-use-it-in-THP-and-KSM/20220831-112149 
> >
> > head:   32b787e37af17f7fe75f9b9c9bb22bf044722229
> > commit: 7ad02cf1645071c2bf1ed6ae0e48907aa0a3119e mm: thp: fix build 
> > error with CONFIG_SHMEM disabled
> > date:   30 hours ago
> > config: sparc-randconfig-r023-20220901 
> > (https://download.01.org/0day-ci/archive/20220902/202209022248.TEjW4Cld-lkp@xxxxxxxxx/config) 
> >
> > compiler: sparc64-linux-gcc (GCC) 12.1.0
> > 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://github.com/intel-lab-lkp/linux/commit/7ad02cf1645071c2bf1ed6ae0e48907aa0a3119e 
> >
> >          git remote add linux-review 
> > https://github.com/intel-lab-lkp/linux
> >          git fetch --no-tags linux-review 
> > UPDATE-20220901-154717/Qi-Zheng/add-common-struct-mm_slot-and-use-it-in-THP-and-KSM/20220831-112149 
> >
> >          git checkout 7ad02cf1645071c2bf1ed6ae0e48907aa0a3119e
> >          # save the config file
> >          mkdir build_dir && cp config build_dir/.config
> >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 
> > make.cross W=1 O=build_dir ARCH=sparc SHELL=/bin/bash
> >
> > If you fix the issue, kindly add following tag where applicable
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > All warnings (new ones prefixed by >>):
> >
> > > > mm/khugepaged.c:2046:56: warning: 'struct khugepaged_mm_slot' 
> > > > declared inside parameter list will not be visible outside of this 
> > > > definition or declaration
> >      2046 | static void khugepaged_collapse_pte_mapped_thps(struct 
> > khugepaged_mm_slot *mm_slot)
> >           |                                                        
> > ^~~~~~~~~~~~~~~~~~
> >     mm/khugepaged.c: In function 'khugepaged_scan_mm_slot':
> >     mm/khugepaged.c:2076:45: error: passing argument 1 of 
> > 'khugepaged_collapse_pte_mapped_thps' from incompatible pointer type 
> > [-Werror=incompatible-pointer-types]
> >      2076 |         khugepaged_collapse_pte_mapped_thps(mm_slot);
> >           |                                             ^~~~~~~
> >           |                                             |
> >           |                                             struct mm_slot *
>
> It looks like the robot tested "mm: thp: fix build error with
> CONFIG_SHMEM disabled" alone without "[PATCH v2 2/7] mm: thp: convert to
> use common struct mm_slot". So this is a false positive.

Hi Qi,

Thanks for the explanation, you are right, the robot was considered this
patch as a replacement of "[PATCH v2 2/7] mm: thp: convert to use common
struct mm_slot".

Best Regards,
Rong Chen

> >     mm/khugepaged.c:2046:76: note: expected 'struct khugepaged_mm_slot 
> > *' but argument is of type 'struct mm_slot *'
> >      2046 | static void khugepaged_collapse_pte_mapped_thps(struct 
> > khugepaged_mm_slot *mm_slot)
> >           |                                                 
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> >     cc1: some warnings being treated as errors
> >
> >
> > vim +2046 mm/khugepaged.c
> >
> >    2045
> > > 2046    static void khugepaged_collapse_pte_mapped_thps(struct 
> > > khugepaged_mm_slot *mm_slot)
> >    2047    {
> >    2048    }
> >    2049    #endif
> >    2050