On Tue, Nov 24, 2020 at 03:43:02PM -0500, Joel Fernandes wrote:
> On Wed, Nov 25, 2020 at 03:22:48AM +0800, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core-sched
> > head:   7b55b5ef19fbadf111b8d60d320437bfc0467a79
> > commit: 636f9841873bff3684ee81155804b796d58408a4 [4/12] sched: Core-wide rq->lock
> > config: powerpc-allyesconfig (attached as .config)
> > compiler: powerpc64-linux-gcc (GCC) 9.3.0
> > 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/peterz/queue.git/commit/?id=636f9841873bff3684ee81155804b796d58408a4
> >         git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git
> >         git fetch --no-tags peterz-queue sched/core-sched
> >         git checkout 636f9841873bff3684ee81155804b796d58408a4
> >         # save the attached .config to linux build tree
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 
> > 
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> > 
> > All warnings (new ones prefixed by >>):
> > 
> > >> kernel/sched/core.c:123:6: warning: no previous prototype for 'sched_core_get' [-Wmissing-prototypes]
> >      123 | void sched_core_get(void)
> >          |      ^~~~~~~~~~~~~~
> > >> kernel/sched/core.c:131:6: warning: no previous prototype for 'sched_core_put' [-Wmissing-prototypes]
> >      131 | void sched_core_put(void)
> >          |      ^~~~~~~~~~~~~~
> >    kernel/sched/core.c:2900:6: warning: no previous prototype for 'sched_set_stop_task' [-Wmissing-prototypes]
> >     2900 | void sched_set_stop_task(int cpu, struct task_struct *stop)
> >          |      ^~~~~~~~~~~~~~~~~~~
> 
> At least this sched_set_stop_task one is not a recently introduced warning.
> 
> This prototype warning does seem bogus though. Do we fix it? Obvious quick
> fix is the declar sched_core_{get,put}() in sched.h to pacify the compiler.

BTW, I did add it to my tree already in:
93de21e503a3 ("sched: Move core-scheduler interfacing code to a new file")
https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/log/?h=coresched

Until the interface patches are in, we could define sched_core_get/put with
"__maybe_unused static" to silence the warnings.

thanks,

 - Joel