[SCSI] target: Add LIO target core v4.0.0-rc6

LIO target is a full featured in-kernel target framework with the
following feature set:

High-performance, non-blocking, multithreaded architecture with SIMD
support.

Advanced SCSI feature set:

    * Persistent Reservations (PRs)
    * Asymmetric Logical Unit Assignment (ALUA)
    * Protocol and intra-nexus multiplexing, load-balancing and failover (MC/S)
    * Full Error Recovery (ERL=0,1,2)
    * Active/active task migration and session continuation (ERL=2)
    * Thin LUN provisioning (UNMAP and WRITE_SAMExx)

Multiprotocol target plugins

Storage media independence:

    * Virtualization of all storage media; transparent mapping of IO to LUNs
    * No hard limits on number of LUNs per Target; maximum LUN size ~750 TB
    * Backstores: SATA, SAS, SCSI, BluRay, DVD, FLASH, USB, ramdisk, etc.

Standards compliance:

    * Full compliance with IETF (RFC 3720)
    * Full implementation of SPC-4 PRs and ALUA

Significant code cleanups done by Christoph Hellwig.

[jejb: fix up for new block bdev exclusive interface. Minor fixes from
 Randy Dunlap and Dan Carpenter.]
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/target/Makefile

@@ -0,0 +1,24 @@
+EXTRA_CFLAGS += -I$(srctree)/drivers/target/ -I$(srctree)/drivers/scsi/
+
+target_core_mod-y		:= target_core_configfs.o \
+				   target_core_device.o \
+				   target_core_fabric_configfs.o \
+				   target_core_fabric_lib.o \
+				   target_core_hba.o \
+				   target_core_pr.o \
+				   target_core_alua.o \
+				   target_core_scdb.o \
+				   target_core_tmr.o \
+				   target_core_tpg.o \
+				   target_core_transport.o \
+				   target_core_cdb.o \
+				   target_core_ua.o \
+				   target_core_rd.o \
+				   target_core_mib.o
+
+obj-$(CONFIG_TARGET_CORE)	+= target_core_mod.o
+
+# Subsystem modules
+obj-$(CONFIG_TCM_IBLOCK)	+= target_core_iblock.o
+obj-$(CONFIG_TCM_FILEIO)	+= target_core_file.o
+obj-$(CONFIG_TCM_PSCSI)		+= target_core_pscsi.o