This patch removes the legacy procfs based target_core_mib.c code,
and moves the necessary scsi_index_tables functions and defines into
target_core_transport.c and target_core_base.h code to allow existing
fabric independent statistics to function.

This includes the removal of a handful of 'atomic_t mib_ref_count'
counters used in struct se_node_acl, se_session and se_hba to prevent
removal while using seq_list procfs walking logic.

[jejb: fix up compile failures]
Signed-off-by: NNicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

This patch fixes two bugs uncovered during testing with
slub_debug=FPUZ during module_exit() -> target_core_exit_configfs()
with release of configfs subsystem consumer default groups, namely how
this should be working with
fs/configfs/dir.c:configfs_unregister_subsystem() release logic for
struct config_group->default_group.

The first issue involves configfs_unregister_subsystem() expecting to
walk+drain the top-level subsys->su_group.default_groups directly in
unlink_group(), and not directly from the configfs subsystem consumer
for the top level struct config_group->default_groups.  This patch
drops the walk+drain of subsys->su_group.default_groups from TCM
configfs subsystem consumer code, and moves the top-level
->default_groups kfree() after configfs_unregister_subsystem() has
been called.

The second issue involves calling
core_alua_free_lu_gp(se_global->default_lu_gp) to release the
default_lu_gp->lu_gp_group before configfs_unregister_subsystem() has
been called.  This patches also moves the core_alua_free_lu_gp() call
to release default_lu_group->lu_gp_group after the subsys has been
unregistered.

Finally, this patch explictly clears the
[lu_gp,alua,hba]_cg->default_groups pointers after kfree() to ensure
that no stale memory is picked up from child struct
config_group->default_group[] while configfs_unregister_subsystem() is
called.
Reported-by: NFubo Chen <fubo.chen@gmail.com>
Signed-off-by: NNicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

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: NNicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>