Hi Naohiro,

I love your patch! Perhaps something to improve:

[auto build test WARNING on kdave/for-next]
[cannot apply to v5.14-rc5 next-20210811]
[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]

url:    https://github.com/0day-ci/linux/commits/Naohiro-Aota/ZNS-Support-for-Btrfs/20210811-222302
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: hexagon-randconfig-r041-20210810 (attached as .config)
compiler: clang version 12.0.0
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/0day-ci/linux/commit/ccecd271dc2436fe587af8d2083c3c96ab86e309
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Naohiro-Aota/ZNS-Support-for-Btrfs/20210811-222302
        git checkout ccecd271dc2436fe587af8d2083c3c96ab86e309
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon 

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 >>):

>> fs/btrfs/zoned.c:1948:2: warning: variable 'ret' is used uninitialized whenever '?:' condition is true [-Wsometimes-uninitialized]
           ASSERT(!list_empty(&block_group->active_bg_list));
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/btrfs/ctree.h:3458:3: note: expanded from macro 'ASSERT'
           (likely(expr) ? (void)0 : assertfail(#expr, __FILE__, __LINE__))
            ^~~~~~~~~~~~
   include/linux/compiler.h:77:20: note: expanded from macro 'likely'
   # define likely(x)      __builtin_expect(!!(x), 1)
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/btrfs/zoned.c:1956:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   fs/btrfs/zoned.c:1948:2: note: remove the '?:' if its condition is always false
           ASSERT(!list_empty(&block_group->active_bg_list));
           ^
   fs/btrfs/ctree.h:3458:3: note: expanded from macro 'ASSERT'
           (likely(expr) ? (void)0 : assertfail(#expr, __FILE__, __LINE__))
            ^
   include/linux/compiler.h:77:20: note: expanded from macro 'likely'
   # define likely(x)      __builtin_expect(!!(x), 1)
                           ^
   fs/btrfs/zoned.c:1908:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   1 warning generated.


vim +1948 fs/btrfs/zoned.c

  1900	
  1901	int btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, u64 logical,
  1902				    u64 length)
  1903	{
  1904		struct btrfs_block_group *block_group;
  1905		struct map_lookup *map;
  1906		struct btrfs_device *device;
  1907		u64 physical;
  1908		int ret;
  1909	
  1910		if (!btrfs_is_zoned(fs_info))
  1911			return 0;
  1912	
  1913		block_group = btrfs_lookup_block_group(fs_info, logical);
  1914		ASSERT(block_group);
  1915	
  1916		if (logical + length < block_group->start + block_group->zone_capacity) {
  1917			ret = 0;
  1918			goto out;
  1919		}
  1920	
  1921		spin_lock(&block_group->lock);
  1922	
  1923		if (!block_group->zone_is_active) {
  1924			spin_unlock(&block_group->lock);
  1925			ret = 0;
  1926			goto out;
  1927		}
  1928	
  1929		block_group->zone_is_active = 0;
  1930		/* We should have consumed all the free space */
  1931		ASSERT(block_group->alloc_offset == block_group->zone_capacity);
  1932		ASSERT(block_group->free_space_ctl->free_space == 0);
  1933		btrfs_clear_treelog_bg(block_group);
  1934		spin_unlock(&block_group->lock);
  1935	
  1936		map = block_group->physical_map;
  1937		device = map->stripes[0].dev;
  1938		physical = map->stripes[0].physical;
  1939	
  1940		if (!device->zone_info->max_active_zones) {
  1941			ret = 0;
  1942			goto out;
  1943		}
  1944	
  1945		btrfs_dev_clear_active_zone(device, physical);
  1946	
  1947		spin_lock(&fs_info->zone_active_bgs_lock);
> 1948		ASSERT(!list_empty(&block_group->active_bg_list));

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org