Re: [PATCH] btrfs: remove unused actions

[kbuild test robot]

Hi Alex,

I love your patch! Perhaps something to improve:

[auto build test WARNING on v5.5-rc7]
[also build test WARNING on next-20200123]
[cannot apply to btrfs/next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Alex-Shi/btrfs-remove-unused-actions/20200124-043621
base:    def9d2780727cec3313ed3522d0123158d87224d
config: powerpc-defconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   fs//btrfs/sysfs.c: In function 'btrfs_sysfs_feature_update':
>> fs//btrfs/sysfs.c:1168:2: warning: ignoring return value of 'sysfs_create_group', declared with attribute warn_unused_result [-Wunused-result]
     sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

vim +/sysfs_create_group +1168 fs//btrfs/sysfs.c

  1140	
  1141	
  1142	/*
  1143	 * Change per-fs features in /sys/fs/btrfs/UUID/features to match current
  1144	 * values in superblock. Call after any changes to incompat/compat_ro flags
  1145	 */
  1146	void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info,
  1147			u64 bit, enum btrfs_feature_set set)
  1148	{
  1149		struct btrfs_fs_devices *fs_devs;
  1150		struct kobject *fsid_kobj;
  1151	
  1152		if (!fs_info)
  1153			return;
  1154	
  1155		ASSERT(bit & supported_feature_masks[set]);
  1156	
  1157		fs_devs = fs_info->fs_devices;
  1158		fsid_kobj = &fs_devs->fsid_kobj;
  1159	
  1160		if (!fsid_kobj->state_initialized)
  1161			return;
  1162	
  1163		/*
  1164		 * FIXME: this is too heavy to update just one value, ideally we'd like
  1165		 * to use sysfs_update_group but some refactoring is needed first.
  1166		 */
  1167		sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group);
> 1168		sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group);
  1169	}
  1170	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
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