ALUA update and Referrals support

Hi Nic,

here's the second version of my ALUA update & Referrals support patches. As per request I've split up the supported states into individual attributes, and while there I've also renamed the rather confusing 'alua_access_type' and 'alua_access_status' into 'alua_management_type' and 'alua_status_modification', respectively.

The other features are:

- Make supported states configurable:
We should make the list of supported ALUA states configurable, as some setups would possibly like to support a small subset of ALUA states only.
- Asynchronous transitioning: I've switched 'transitioning' handling to use a workqueue, that should allow us to simulate asynchronous transitioning modes. IE TCM should now be capable of handling requests while in transitioning, and properly terminate these with the correct sense code.
- Include target device descriptor in VPD page 83
For the ALUA device handler we'd need to identify the target device where a given target port belongs to. So include the respective values in the VPD page.

And, of course, referrals support.

Hannes Reinecke (18):
target core: rename (ex,im)plict -> (ex,im)plicit
target_core_alua: spellcheck
target_core_alua: Rename ALUA_ACCESS_STATE_OPTIMIZED
target_core_alua: Store supported ALUA states
target_core_alua: Make supported states configurable
target_core_configfs: split up ALUA supported states
target_core_configfs: Verbose ALUA state display
target_core_configfs: Split up ALUA access type
target_core: Rename alua_access_type in alua_mgmt_type
target_core: Rename alua_access_status to alua_status_modification
target_core_alua: Validate ALUA state transition
target_core_alua: Allocate ALUA metadata on demand
target_core_alua: store old and pending ALUA state
target_core_alua: Use workqueue for ALUA transitioning
target_core: simplify scsi_name_len calculation
target_core_spc: Include target device descriptor in VPD page 83
target_core_alua: Referrals infrastructure
target_core_alua: Referrals configfs integration

 drivers/target/target_core_alua.c      | 764 +++++++++++++++++++++++----------
 drivers/target/target_core_alua.h      |  55 ++-
 drivers/target/target_core_configfs.c  | 360 ++++++++++++++--
 drivers/target/target_core_device.c    |   9 +-
 drivers/target/target_core_file.c      |   2 +-
 drivers/target/target_core_pr.c        |  24 +-
 drivers/target/target_core_sbc.c       |   5 +-
 drivers/target/target_core_spc.c       |  84 +++-
 drivers/target/target_core_transport.c |  32 +-
 drivers/target/target_core_ua.h        |   2 +-
 include/scsi/scsi.h                    |   1 +
 include/target/target_core_base.h      |  34 +-
 12 files changed, 1050 insertions(+), 322 deletions(-)

1.7.12.4