Merge tag 'for-4.12/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull device mapper fixes from Mike Snitzer:

 - a couple DM thin provisioning fixes

 - a few request-based DM and DM multipath fixes for issues that were
   made when merging Christoph's changes with Bart's changes for 4.12

 - a DM bufio unsigned overflow fix

 - a couple pure fixes for the DM cache target.

 - various very small tweaks to the DM cache target that enable
   considerable speed improvements in the face of continuous IO. Given
   that the cache target was significantly reworked for 4.12 I see no
   reason to sit on these advances until 4.13 considering the favorable
   results associated with such minimalist tweaks.

* tag 'for-4.12/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: handle kmalloc failure allocating background_tracker struct
  dm bufio: make the parameter "retain_bytes" unsigned long
  dm mpath: multipath_clone_and_map must not return -EIO
  dm mpath: don't return -EIO from dm_report_EIO
  dm rq: add a missing break to map_request
  dm space map disk: fix some book keeping in the disk space map
  dm thin metadata: call precommit before saving the roots
  dm cache policy smq: don't do any writebacks unless IDLE
  dm cache: simplify the IDLE vs BUSY state calculation
  dm cache: track all IO to the cache rather than just the origin device's IO
  dm cache policy smq: stop preemptively demoting blocks
  dm cache policy smq: put newly promoted entries at the top of the multiqueue
  dm cache policy smq: be more aggressive about triggering a writeback
  dm cache policy smq: only demote entries in bottom half of the clean multiqueue
  dm cache: fix incorrect 'idle_time' reset in IO tracker