Re: [PATCH RFC] btrfs: sysfs: add <uuid>/debug/io_accounting/ directory

[kernel test robot <yujie.liu@intel.com>]

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Hi Wenruo,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on kdave/for-next]
[also build test WARNING on v5.17-rc1 next-20220125]
[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/Qu-Wenruo/btrfs-sysfs-add-uuid-debug-io_accounting-directory/20220121-132629
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: x86_64-randconfig-c007-20220124 (https://download.01.org/0day-ci/archive/20220126/202201260130.4VVHtyiM-lkp(a)intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 997e128e2a78f5a5434fc75997441ae1ee76f8a4)
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/879aebce4c7d6a684b93b92545978dc75bf4abd5
         git remote add linux-review https://github.com/0day-ci/linux
         git fetch --no-tags linux-review Qu-Wenruo/btrfs-sysfs-add-uuid-debug-io_accounting-directory/20220121-132629
         git checkout 879aebce4c7d6a684b93b92545978dc75bf4abd5
         # save the config file to linux build tree
         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 clang-analyzer

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


clang-analyzer warnings: (new ones prefixed by >>)

 >> fs/btrfs/volumes.c:6780:6: warning: Value stored to 'length' during its initialization is never read [clang-analyzer-deadcode.DeadStores]
            u32 length = bio->bi_iter.bi_size;
                ^~~~~~   ~~~~~~~~~~~~~~~~~~~~
 >> fs/btrfs/volumes.c:6781:7: warning: Value stored to 'metadata' during its initialization is never read [clang-analyzer-deadcode.DeadStores]
            bool metadata = bio->bi_opf & REQ_META;
                 ^~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~

vim +/length +6780 fs/btrfs/volumes.c

de1ee92ac3bce4 Josef Bacik 2012-10-19  6777
879aebce4c7d6a Qu Wenruo   2022-01-21  6778  static void update_io_accounting(struct btrfs_fs_info *fs_info, struct bio *bio)
879aebce4c7d6a Qu Wenruo   2022-01-21  6779  {
879aebce4c7d6a Qu Wenruo   2022-01-21 @6780  	u32 length = bio->bi_iter.bi_size;
879aebce4c7d6a Qu Wenruo   2022-01-21 @6781  	bool metadata = bio->bi_opf & REQ_META;
879aebce4c7d6a Qu Wenruo   2022-01-21  6782

## this build has CONFIG_BTRFS_DEBUG=n ##

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