Re: [PATCH v3 1/4] arch_topology: Support basic SMT control for the driver

[Yicong Yang <yangyicong@huawei.com>]

On 2023/11/15 23:23, kernel test robot wrote:
> Hi Yicong,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on arm64/for-next/core]
> [also build test WARNING on driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus arm/for-next kvmarm/next soc/for-next linus/master arm/fixes v6.7-rc1 next-20231115]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Yicong-Yang/arch_topology-Support-basic-SMT-control-for-the-driver/20231114-120544
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
> patch link:    https://lore.kernel.org/r/20231114040110.54590-2-yangyicong%40huawei.com
> patch subject: [PATCH v3 1/4] arch_topology: Support basic SMT control for the driver
> config: arm-socfpga_defconfig (https://download.01.org/0day-ci/archive/20231115/202311152356.OWWDpFRB-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231115/202311152356.OWWDpFRB-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/202311152356.OWWDpFRB-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>>> drivers/base/arch_topology.c:32:12: warning: unused variable 'topology_smt_num_threads' [-Wunused-variable]
>       32 | static int topology_smt_num_threads = 1;
>          |            ^
>    1 warning generated.
> 

This variable needs to be protected by CONFIG_HOTPLUG_SMT, otherwise it'll be unused
if architecture like arm/parisc selects CONFIG_GENERIC_ARCH_TOPOLOGY but not
CONFIG_HOTPLUG_SMT.

> 
> vim +/topology_smt_num_threads +32 drivers/base/arch_topology.c
> 
>     30	
>     31	/* Maximum threads number per-Core */
>   > 32	static int topology_smt_num_threads = 1;
>     33	
>