Merge tag 'md-3.10' of git://neil.brown.name/md

Pull md fixes from NeilBrown:
 "A mixed bag of little fixes.  No real new functionality here.  Several
  patches are tagged for -stable."

* tag 'md-3.10' of git://neil.brown.name/md:
  MD: ignore discard request for hard disks of hybid raid1/raid10 array
  md: bad block list should default to disabled.
  md: raid1/raid10 md devices leak memory when stopping
  DM RAID: Add message/status support for changing sync action
  MD: Export 'md_reap_sync_thread' function
  md: don't update metadata when stopping a read-only array.
  md: Allow devices to be re-added to a read-only array.
  md/raid10: Allow skipping recovery when clean arrays are assembled
  MD: Fix typos in MD documentation
  md/raid5: avoid an extra write when writing to a known-bad-block.
  md/raid5: Change or of some order to improve efficiency.
  md: use set_bit_le and clear_bit_le
  md: HOT_DISK_REMOVE shouldn't make a read-auto device active.
  md: use common code for all calls to ->hot_remove_disk()
  md: never update metadata when array is read-only.