. Add dm_accept_partial_bio interface to DM core to allow DM targets

  to only process a portion of a bio, the remainder being sent in the
  next bio.  This enables the old dm snapshot-origin target to only
  split write bios on chunk boundaries, read bios are now sent to the
  origin device unchanged.

. Add DM core support for disabling WRITE SAME if the underlying SCSI
  layer disables it due to command failure.

. Reduce lock contention in DM's bio-prison.

. A few small cleanups and fixes to dm-thin and dm-era.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iQEcBAABAgAGBQJTmavIAAoJEMUj8QotnQNay/EIAJI6lEFlQK3gG830+Yaw1m2U
7mnnX/Rd/N6RnccyhmFqk7Xu0REM7gJEgWicTQjR58La2DKFi072N0mwgHgHfB8f
1oOvUKN5Nb/a1CmRcVzSO0sbYcJn9I1r+k0buqfFHivU68wuedG+MrVya3YzOjvC
63MQiu4+3icDprcToxn+etz75FhrFps5QAsS0cH6t1VZqFCGIzxqgUKgY8zGo1CH
P9hkYpJhhJe2aDh4vlFvpFYVFXt9zPoR+MkqXFW6Dn9GbR36gGaldTwnyhapla4N
XYHDEdETcTqm2srOM5wW+jD0p+Id9/Lmd5Ld5J2zyARCYn/EG/SDCbiaVqOxEnc=
=tv1B
-----END PGP SIGNATURE-----