[PATCH] ACPI: GTDT: simplify acpi_gtdt_init() implementation

[kernel test robot]

Hi Zheng,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on rafael-pm/bleeding-edge tip/timers/core linus/master v6.12-rc1 next-20240930]
[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/Zheng-Zengkai/ACPI-GTDT-simplify-acpi_gtdt_init-implementation/20240930-105041
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20240930030716.179992-1-zhengzengkai%40huawei.com
patch subject: [PATCH] ACPI: GTDT: simplify acpi_gtdt_init() implementation
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20241001/202410010101.2oPkEaoP-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 7773243d9916f98ba0ffce0c3a960e4aa9f03e81)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241001/202410010101.2oPkEaoP-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410010101.2oPkEaoP-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/acpi/arm64/gtdt.c:11:
   In file included from include/linux/acpi.h:39:
   In file included from include/acpi/acpi_io.h:7:
   In file included from arch/arm64/include/asm/acpi.h:14:
   In file included from include/linux/memblock.h:12:
   In file included from include/linux/mm.h:2236:
   include/linux/vmstat.h:503:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     503 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     504 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:510:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     510 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     511 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:517:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     517 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:523:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     523 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     524 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
>> drivers/acpi/arm64/gtdt.c:383:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     383 |         if (!timer_count)
         |             ^~~~~~~~~~~~
   drivers/acpi/arm64/gtdt.c:400:9: note: uninitialized use occurs here
     400 |         return ret;
         |                ^~~
   drivers/acpi/arm64/gtdt.c:383:2: note: remove the 'if' if its condition is always false
     383 |         if (!timer_count)
         |         ^~~~~~~~~~~~~~~~~
     384 |                 goto out_put_gtdt;
         |                 ~~~~~~~~~~~~~~~~~
   drivers/acpi/arm64/gtdt.c:365:9: note: initialize the variable 'ret' to silence this warning
     365 |         int ret, timer_count = 0, gwdt_count = 0;
         |                ^
         |                 = 0
   5 warnings generated.


vim +383 drivers/acpi/arm64/gtdt.c

   360	
   361	static int __init gtdt_sbsa_gwdt_init(void)
   362	{
   363		void *platform_timer;
   364		struct acpi_table_header *table;
   365		int ret, timer_count = 0, gwdt_count = 0;
   366	
   367		if (acpi_disabled)
   368			return 0;
   369	
   370		if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table)))
   371			return -EINVAL;
   372	
   373		/*
   374		 * Note: Even though the global variable acpi_gtdt_desc has been
   375		 * initialized by acpi_gtdt_init() while initializing the arch timers,
   376		 * when we call this function to get SBSA watchdogs info from GTDT, the
   377		 * pointers stashed in it are stale (since they are early temporary
   378		 * mappings carried out before acpi_permanent_mmap is set) and we need
   379		 * to re-initialize them with permanent mapped pointer values to let the
   380		 * GTDT parsing possible.
   381		 */
   382		acpi_gtdt_init(table, &timer_count);
 > 383		if (!timer_count)
   384			goto out_put_gtdt;
   385	
   386		for_each_platform_timer(platform_timer) {
   387			if (is_non_secure_watchdog(platform_timer)) {
   388				ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count);
   389				if (ret)
   390					break;
   391				gwdt_count++;
   392			}
   393		}
   394	
   395		if (gwdt_count)
   396			pr_info("found %d SBSA generic Watchdog(s).\n", gwdt_count);
   397	
   398	out_put_gtdt:
   399		acpi_put_table(table);
   400		return ret;
   401	}
   402	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki