[PATCH v4 0/2] dm unstriped: add new target

[Heinz Mauelshagen <heinzm@redhat.com>]

This is a quick rework of the new "unstripe" target
(undoes a striped/raid0 mapping) v3 patch series
authored by Scott Bauer addressing some points
discussed here and more.

Addressed:
- rename target to "unstriped"
- enhance constructor header
- add more consistency checks to constructor imposing
  divisibility of device and drive length by chunk size;
  device length has to be divisible by total number of drives
- use destructor in constructor error pathes
- move a few local variables to 'struct unstripe'
- add missing unstripe_status() function using
  new variables in ^ struct to address requirement
  for dm targets
- tweaked config variable name Kconfig text

Not addressed:
- documentation (kept as is in this series for completeness) 

Example of 'dmsetup table' output:
# dmsetup table nvm-s s1 s2
nvm-s: 0 262144 raid raid0 1 8 2 - 254:2 - 254:3
s1: 0 131072 unstriped 254:4 0 2 8
s2: 0 131072 unstriped 254:4 1 2 8


Scott,
please check, test and tell, if the additonal constraints
on length divisibility are too restrictive and how to go
about the 2 FIXMEs.


Tested-by: Heinz Mauelshagen <heinzm@redhat.com>

Heinz Mauelshagen (2):
  dm unstriped: new "unstriped" raid0/striped device
  dm unstriped: add documentation for unstriped target

 Documentation/device-mapper/dm-unstripe.txt | 130 ++++++++++++++++
 drivers/md/Kconfig                          |  11 ++
 drivers/md/Makefile                         |   1 +
 drivers/md/dm-unstripe.c                    | 233 ++++++++++++++++++++++++++++
 4 files changed, 375 insertions(+)
 create mode 100644 Documentation/device-mapper/dm-unstripe.txt
 create mode 100644 drivers/md/dm-unstripe.c

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2.14.3