This patch is part of dm/md dependency tree in sysfs.

Following symlinks are created if dm-0 maps to sda:
  /sys/block/dm-0/slaves/sda --> /sys/block/sda
  /sys/block/sda/holders/dm-0 --> /sys/block/dm-0

This patch depends on the following patches in mm tree:
  dm-tidy-mdptr.patch
  dm-table-store-md.patch

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.