[pci:controller/xilinx-xdma] BUILD REGRESSION 8d786149d78c7784144c7179e25134b6530b714b

[Bjorn Helgaas]

On Tue, Oct 31, 2023 at 09:59:29AM -0700, Nick Desaulniers wrote:
> On Tue, Oct 31, 2023 at 7:56 AM Bjorn Helgaas <helgaas at kernel.org> wrote:
> > On Sat, Oct 28, 2023 at 08:22:54PM +0800, kernel test robot wrote:
> > > tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git controller/xilinx-xdma
> > > branch HEAD: 8d786149d78c7784144c7179e25134b6530b714b  PCI: xilinx-xdma: Add Xilinx XDMA Root Port driver
> > >
> > > Error/Warning ids grouped by kconfigs:
> > >
> > > clang_recent_errors
> > > `-- powerpc-pmac32_defconfig
> > >     |-- arch-powerpc-sysdev-grackle.c:error:unused-function-grackle_set_stg-Werror-Wunused-function
> > >     |-- arch-powerpc-xmon-xmon.c:error:unused-function-get_output_lock-Werror-Wunused-function
> > >     `-- arch-powerpc-xmon-xmon.c:error:unused-function-release_output_lock-Werror-Wunused-function
> >
> > This report is close to useless.  It doesn't show the complete error
> > message, it doesn't show how to reproduce the issue, and the pci -next
> > branch (including controller/xilinx-xdma) doesn't reference any of
> > these functions:
> >
> >   $ git grep -E "grackle_set_stg|get_output_lock|release_output_lock" | cat
> >   arch/powerpc/sysdev/grackle.c:static inline void grackle_set_stg(struct pci_controller* bp, int enable)
> >   arch/powerpc/sysdev/grackle.c:        grackle_set_stg(hose, 1);
> >   arch/powerpc/xmon/xmon.c:static void get_output_lock(void)
> >   arch/powerpc/xmon/xmon.c:static void release_output_lock(void)
> >   arch/powerpc/xmon/xmon.c:static inline void get_output_lock(void) {}
> >   arch/powerpc/xmon/xmon.c:static inline void release_output_lock(void) {}
> >   arch/powerpc/xmon/xmon.c:             get_output_lock();
> >   arch/powerpc/xmon/xmon.c:             release_output_lock();
> >   arch/powerpc/xmon/xmon.c:                     get_output_lock();
> >   arch/powerpc/xmon/xmon.c:                     release_output_lock();
> >   arch/powerpc/xmon/xmon.c:             get_output_lock();
> >   arch/powerpc/xmon/xmon.c:             release_output_lock();
> >   arch/powerpc/xmon/xmon.c:             get_output_lock();
> >   arch/powerpc/xmon/xmon.c:             release_output_lock();
> >
> > That said, the unused functions do look legit:
> >
> > grackle_set_stg() is a static function and the only call is under
> > "#if 0".
> 
> Time to remove it then? Or is it a bug that it's not called?
> Otherwise the definition should be behind the same preprocessor guards
> as the caller.  Same for the below.

I don't really care whether we keep the warning or not.

My real complaint is that the 0-day report fingered
pci/controller/xilinx-xdma, which is completely unrelated, which is a
waste of time.

> > Same with get_output_lock() and release_output_lock(): they're static
> > and always defined in xmon.c, but only called if either CONFIG_SMP or
> > CONFIG_DEBUG_FS.
> >
> > But they're certainly not related to controller/xilinx-xdma, so I'm
> > going to ignore them.
> >
> > Bjorn
> >
> > P.S. Nathan & Nick, I cc'd you because of this earlier report that
> > also mentioned grackle_set_stg():
> > https://lore.kernel.org/lkml/202308121120.u2d3YPVt-lkp@intel.com/
> 
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers