This patch adds support for EXTENDED_COPY emulation from SPC-3, that
enables full copy offload target support within both a single virtual
backend device, and across multiple virtual backend devices.  It also
functions independent of target fabric, and supports copy offload
across multiple target fabric ports.

This implemenation supports both EXTENDED_COPY PUSH and PULL models
of operation, so the actual CDB may be received on either source or
desination logical unit.

For Target Descriptors, it currently supports the NAA IEEE Registered
Extended designator (type 0xe4), which allows the reference of target
ports to occur independent of fabric type using EVPD 0x83 WWNs.

For Segment Descriptors, it currently supports copy from block to
block (0x02) mode.

It also honors any present SCSI reservations of the destination target
port.  Note that only Supports No List Identifier (SNLID=1) mode is
supported.

Also included is basic RECEIVE_COPY_RESULTS with service action type
OPERATING PARAMETERS (0x03) required for SNLID=1 operation.

v3 changes:
  - Fix incorrect return type in target_do_receive_copy_results()
    (Fengguang)

v2 changes:
  - Use target_alloc_sgl() instead of transport_generic_get_mem()
  - Convert debug output to use pr_debug()
  - Convert target_xcopy_parse_target_descriptors() NAA IEEN WWN
    dump to use 0x%16phN format specification
  - Drop unnecessary xcopy_pt_cmd->xpt_passthrough_wsem, and
    associated usage in xcopy_pt_write_pending() and
    target_xcopy_issue_pt_cmd()
  - Add check for unsupported EXTENDED_COPY(LID4) service action
    bits in target_do_xcopy()

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds an check for a non-existent port->sep_alua_tg_pt_gp_mem
within target_alua_state_check(), which is not present for internally
dispatched EXTENDED_COPY WRITE I/O to the destination target port.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

EXTENDED_COPY needs to be able to search a global list of devices
based on NAA WWN device identifiers, so add a simple g_device_list
protected by g_device_mutex.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

Both target_alloc_sgl() and transport_generic_map_mem_to_cmd() are
required by EXTENDED_COPY logic when setting up internally dispatched
command descriptors, so go ahead and make both of these non static.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch makes spc_parse_naa_6h_vendor_specific() available to
other target code, which is required by EXTENDED_COPY when comparing
the received NAA WWN device identifer for locating the associated
se_device backend.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch makes the top-level target_core_subsystem array available
to other target code, which is required by EXTENDED_COPY to pin the
backend se_device using configfs_depend_item(), in order to ensure
it can't be removed for the duration of a EXTENDED_COPY operation.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

Reversing the dma_data_direction for pci_map_sg() friends is useful
for other drivers, so move it from tcm_qla2xxx into inline code
within target_core_fabric.h.

Also drop internal usage of equivlient in tcm_qla2xxx fabric code.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Cc: Chad Dupuis <chad.dupuis@qlogic.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds a extra check for SCF_COMPARE_AND_WRITE within
transport_generic_request_failure() to invoke the callback for
compare_and_write_callback() or compare_and_write_done(), in
order to release se_dev->caw_mutex from the generic failure
path.

It also adds to checks within compare_and_write_callback() to
avoid processing when transport_generic_request_failure() occurs
early enough that cmd->t_data_sg or cmd->t_bidi_data_sg have not
been setup yet, nor se_dev->caw_mutex obtained from within
sbc_compare_and_write().

v4 changes:
 - Add explicit check for cmd->transport_complete_callback in
   transport_generic_request_failure() to handle case where
   sbc_compare_and_write()clears callback pointer (Dan Carpenter)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch changes target_complete_ok_work() to fall through
after calling the se_cmd->transport_complete_callback() ->
compare_and_write_post() callback, by keying off the existance
of SCF_COMPARE_AND_WRITE_POST.

This is necessary because once SCF_COMPARE_AND_WRITE_POST has
been set by compare_and_write_post(), the SCSI response needs
to be sent via TFO->queue_status().

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds support for COMPARE_AND_WRITE emulation on a per block
basis.  This logic is used as an atomic test and set primative currently
used by VMWare ESX VAAI for performing array side locking of individual
VMFS extent ownership.

This includes the COMPARE_AND_WRITE CDB parsing within sbc_parse_cdb(),
and does the majority of the work within the compare_and_write_callback()
to perform the verify instance user data comparision, and subsequent
write instance user data I/O submission upon a successfull comparision.

The synchronization is enforced by se_device->caw_sem, that is obtained
before the initial READ I/O submission in sbc_compare_and_write().  The
mutex is then released upon MISCOMPARE in compare_and_write_callback(),
or upon WRITE instance user-data completion in compare_and_write_post().

The implementation currently assumes a single logical block (NoLB=1).

v4 changes:
 - Explicitly clear cmd->transport_complete_callback for two failure
   cases in sbc_compare_and_write() in order to avoid double unlock
   of ->caw_sem in compare_and_write_callback() (Dan Carpenter)

v3 changes:
 - Convert se_device->caw_mutex to ->caw_sem

v2 changes:
 - Set SCF_COMPARE_AND_WRITE and cmd->execute_cmd() to
   sbc_compare_and_write() during setup in sbc_parse_cdb()
 - Use sbc_compare_and_write() for initial READ submission with
   DMA_FROM_DEVICE
 - Reset cmd->execute_cmd() to sbc_execute_rw() for write instance
   user-data in compare_and_write_callback()
 - Drop SCF_BIDI command flag usage
 - Set TRANSPORT_PROCESSING + transport_state flags before write
   instance submission, and convert to __target_execute_cmd()
 - Prevent sbc_get_size() from being being called twice to
   generate incorrect size in sbc_parse_cdb()
 - Enforce se_device->caw_mutex synchronization between initial
   READ I/O submission, and final WRITE I/O completion.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds the MAXIMUM COMPARE AND WRITE LENGTH bit, currently
hardcoded to a single logical block (NoLB=1) within the Block Limits
VPD in spc_emulate_evpd_b0().

Also add emulate_caw device attribute in configfs (enabled by default)
to allow the exposure of this bit to be disabled, if necessary.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

Required by COMPARE_AND_WRITE for write instance user-data
submission, in order to bypass target_execute_cmd() checks.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

After COMPARE_AND_WRITE completes it's comparision, the WRITE
payload SGLs head expect to be updated to point from the verify
instance of user data, to the write instance of user data.

So for this special case, add transport_reset_sgl_orig() usage
within transport_free_pages() and add se_cmd->t_data_[sg,nents]_orig
members to save the original assignments.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch updates transport_generic_new_cmd() to call target_alloc_sgl()
for SGL + page memory allocation for se_cmd->t_bidi_data_sg.

It also adds the special case for SCF_COMPARE_AND_WRITE to calculate a
different bidi_length based upon se_cmd->t_task_nolb.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch refactors transport_generic_get_mem() to target_alloc_sgl()
for accepting **sgl, *nents, length and zero_page as function parameters
in order to be used for both se_cmd->t_data_sg + se_cmd->t_bidi_data_sg
allocations.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

Stop keying off se_cmd->t_bidi_data_sg within transport_complete_qf()
+ target_complete_ok_work(), and just use SCF_BIDI instead.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

COMPARE_AND_WRITE expects to be able to send down a DMA_FROM_DEVICE
to obtain the necessary READ payload for comparision against the
first half of the WRITE payload containing the verify user data.

Currently virtual backends expect to internally reference SGLs,
SGL nents, and data_direction, so change IBLOCK, FILEIO and RD
sbc_ops->execute_rw() to accept this values as function parameters.

Also add default sbc_execute_rw() handler for the typical case for
cmd->execute_rw() submission using cmd->t_data_sg, cmd->t_data_nents,
and cmd->data_direction).

v2 Changes:
  - Add SCF_COMPARE_AND_WRITE command flag
  - Use sbc_execute_rw() for normal cmd->execute_rw() submission
    with expected se_cmd members.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds TCM_MISCOMPARE_VERIFY (ASC=0x1d, ASCQ=0x00) sense
handling to transport_send_check_condition_and_sense(), which is
required for a COMPARE_AND_WRITE comparision failure.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds a sense_reason_t return to ->transport_complete_callback(),
and updates target_complete_ok_work() to invoke the call if necessary to
transport_send_check_condition_and_sense() during the failure case.

Also update xdreadwrite_callback() to use this return value.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

blk_get_request() just returns NULL on error, it doesn't return an
ERR_PTR.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch changes iscsi-target to use transport_alloc_session_tags()
pre-allocation logic for per-cpu session tag pooling with internal
ida_alloc() + ida_free() calls based upon the saved se_cmd->map_tag id.

This includes tag pool setup based upon per NodeACL queue_depth after
locating se_node_acl in iscsi_target_locate_portal().

Also update iscsit_allocate_cmd() and iscsit_release_cmd() to use
percpu_ida_alloc() and percpu_ida_free() respectively.

v5 changes;
  - Convert to percpu_ida.h include

v2 changes:
  - Fix bug with SessionType=Discovery in iscsi_target_locate_portal()

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This command converts iscsi/isert-target to use allocations based on
iscsit_transport->priv_size within iscsit_allocate_cmd(), instead of
using an embedded isert_cmd->iscsi_cmd.

This includes removing iscsit_transport->alloc_cmd() usage, along
with updating isert-target code to use iscsit_priv_cmd().

Also, remove left-over iscsit_transport->release_cmd() usage for
direct calls to iscsit_release_cmd(), and drop the now unused
lio_cmd_cache and isert_cmd_cache.

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

This patch adds support for pre-allocation of per tv_cmd descriptor
scatterlist + user-space page pointer memory using se_sess->sess_cmd_map
within tcm_vhost_make_nexus() code.

This includes sanity checks within vhost_scsi_map_to_sgl()
to reject I/O that exceeds these initial hardcoded values, and
the necessary cleanup in tcm_vhost_make_nexus() failure path +
tcm_vhost_drop_nexus().

v3 changes:
  - Rebase to v3.11-rc5 code

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Asias He <asias@redhat.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Reviewed-by: Asias He <asias@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch changes vhost/scsi to use transport_init_session_tags()
pre-allocation logic for per-cpu session tag pooling with internal
ida_alloc() + ida_free() calls based upon the saved se_cmd->map_tag id.

FIXME: Make transport_init_session_tags() number of tags setup
configurable per vring client setting via configfs

v5 changes:
 - Convert to percpu_ida.h include

v3 changes:
 - Update to percpu-ida usage
 - Rebase to v3.11-rc5 code

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Asias He <asias@redhat.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds lib/idr.c based transport_init_session_tags() logic
that allows fabric drivers to setup a per-cpu se_sess->sess_tag_pool
and associated se_sess->sess_cmd_map for basic tagged pre-allocation
of fabric descriptor sized memory.

v5 changes:
  - Convert to percpu_ida.h include

v4 changes:
  - Add transport_alloc_session_tags() for fabrics that need early
    transport_init_session()

v3 changes:
  - Update to percpu-ida usage

Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Asias He <asias@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Percpu frontend for allocating ids. With percpu allocation (that works),
it's impossible to guarantee it will always be possible to allocate all
nr_tags - typically, some will be stuck on a remote percpu freelist
where the current job can't get to them.

We do guarantee that it will always be possible to allocate at least
(nr_tags / 2) tags - this is done by keeping track of which and how many
cpus have tags on their percpu freelists. On allocation failure if
enough cpus have tags that there could potentially be (nr_tags / 2) tags
stuck on remote percpu freelists, we then pick a remote cpu at random to
steal from.

Note that there's no cpu hotplug notifier - we don't care, because
steal_tags() will eventually get the down cpu's tags. We _could_ satisfy
more allocations if we had a notifier - but we'll still meet our
guarantees and it's absolutely not a correctness issue, so I don't think
it's worth the extra code.

From akpm:

    "It looks OK to me (that's as close as I get to an ack :))

v6 changes:
  - Add #include <linux/cpumask.h> to include/linux/percpu_ida.h to
    make alpha/arc builds happy (Fengguang)
  - Move second (cpu >= nr_cpu_ids) check inside of first check scope
    in steal_tags() (akpm + nab)

v5 changes:
  - Change percpu_ida->cpus_have_tags to cpumask_t (kmo + akpm)
  - Add comment for percpu_ida_cpu->lock + ->nr_free (kmo + akpm)
  - Convert steal_tags() to use cpumask_weight() + cpumask_next() +
    cpumask_first() + cpumask_clear_cpu() (kmo + akpm)
  - Add comment for alloc_global_tags() (kmo + akpm)
  - Convert percpu_ida_alloc() to use cpumask_set_cpu() (kmo + akpm)
  - Convert percpu_ida_free() to use cpumask_set_cpu() (kmo + akpm)
  - Drop percpu_ida->cpus_have_tags allocation in percpu_ida_init()
    (kmo + akpm)
  - Drop percpu_ida->cpus_have_tags kfree in percpu_ida_destroy()
    (kmo + akpm)
  - Add comment for percpu_ida_alloc @ gfp (kmo + akpm)
  - Move to percpu_ida.c + percpu_ida.h (kmo + akpm + nab)

v4 changes:

  - Fix tags.c reference in percpu_ida_init (akpm)
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch updates iser-target code to support login negotiation
multi-plexing.  This includes only using isert_conn->conn_login_comp
for the first login request PDU, pushing the subsequent processing
to iscsi_conn->login_work -> iscsi_target_do_login_rx(), and turning
isert_get_login_rx() into a NOP.

v3 changes:
   - Drop unnecessary LOGIN_FLAGS_READ_ACTIVE bit set in
     isert_rx_login_req()
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

There is no need for iscsi_target_do_login_io() anymore in modern code,
so go ahead and call iscsi_target_do_tx_login_io() directly within
iscsi_target_do_login().
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds a sock->sk_state_change() -> iscsi_target_sk_state_change()
callback in order to handle transient TCP failures during the login process,
where sock->sk_data_ready() -> iscsi_target_sk_data_ready() may not be
called to release connection resources, and relinquish tpg->np_login_lock
via iscsit_deaccess_np()

It performs the sk->sk_state check using iscsi_target_sk_state_check() to
look for TCP_CLOSE_WAIT + TCP_CLOSE, and invokes schedule_delayed_work() ->
iscsi_target_do_cleanup() to perform the remaining cleanup from process
context.

It adds an explicit sk_state_check to iscsi_target_do_login() in order
to determine a state failure when iscsi_target_sk_state_change() may
not be able to proceed before LOGIN_FLAGS_READY=1 is set.

Also use sk->sk_sndtimeo -> sk->sk_rcvtimeo settings during login to
iscsi_target_set_sock_callbacks(), and revert back post login to use
MAX_SCHEDULE_TIMEOUT in iscsi_target_restore_sock_callbacks().
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds support for login negotiation multi-plexing in
iscsi-target code.

This involves handling the first login request PDU + payload and
login response PDU + payload within __iscsi_target_login_thread()
process context, and then changing struct sock->sk_data_ready()
so that all subsequent exchanges are handled by workqueue process
context, to allow other incoming login requests to be received
in parallel by __iscsi_target_login_thread().

Upon login negotiation completion (or failure), ->sk_data_ready()
is replaced with the original kernel sockets handler saved in
iscsi_conn->orig_data_ready.

v3 changes:
  - Convert iscsi_target_sk_data_ready() lock access to
    write[lock,unlock]_bh()
  - Only clear LOGIN_FLAGS_READ_ACTIVE when iscsi_target_do_login()
    returns zero
  - Add LOGIN_FLAGS_READY + LOGIN_FLAGS_CLOSED bit checks to
    iscsi_target_sk_data_ready()
  - Make INIT_DELAYED_WORK() + iscsi_target_set_sock_callbacks() setup
    happen earlier by moving from iscsi_target_start_negotiation() into
    iscsi_target_locate_portal()
  - Set LOGIN_FLAGS_READY bit in iscsi_target_start_negotiation()
    after iscsi_target_do_login() returns zero.

v2 changes:
  - Add login_timer in iscsi_target_do_login_rx() to avoid
    possible endless sleep with MSG_WAITALL for traditional
    iscsi-target in certain network configurations.
  - Convert lprintk() -> pr_debug()
  - Remove forward declarations of iscsi_target_set_sock_callbacks(),
    iscsi_target_restore_sock_callbacks() and iscsi_target_sk_data_ready()
  - Make iscsi_target_set_sock_callbacks + iscsi_target_restore_sock_callbacks()
    static (Fengguang)
  - Make iscsi_target_do_login_rx() safe for iser-target w/o conn->sock
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch prepares the iscsi-target login code for multi-plexing
support.  This includes:

 - Adding iscsi_tpg_np->tpg_np_kref + iscsit_login_kref_put() for
   handling callback of iscsi_tpg_np->tpg_np_comp
 - Adding kref_put() in iscsit_deaccess_np()
 - Adding kref_put() and wait_for_completion() in
   iscsit_reset_np_thread()
 - Refactor login failure path release logic into
   iscsi_target_login_sess_out()
 - Update __iscsi_target_login_thread() to handle
   iscsi_post_login_handler() asynchronous completion
 - Add shutdown parameter for iscsit_clear_tpg_np_login_thread*()

v3 changes:
 - Convert iscsi_portal_group->np_login_lock to ->np_login_sem
 - Add LOGIN_FLAGS definitions

v2 changes:
 - Remove duplicate call to iscsi_post_login_handler() in
   __iscsi_target_login_thread()
 - Drop unused iscsi_np->np_login_tpg
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Odd little issue, found that if you create an IPv6 portal bound to the
IN6ADDR_ANY wildcard address it will accept IPv4 connections (as long as
bindv6only isn't set globally) but respond to SendTargets requests with
an IPv4-mapped IPv6 address.

Example over loopback:

 In targetcli create a wildcard IPv6 portal
   /iscsi/iqn.../portals/> create ::
 Which should create a portal [::]:3260

 Initiate SendTargets discovery to the portal using an IPv4 address
   # iscsiadm -m discovery -t st -p 127.0.0.1
 The response formats TargetAddress as [::ffff:127.0.0.1]:3260,1

This still works and uses v4 on the network between two v6 sockets, but
only if the initiator supports IPv6 with v4-mapped addresses.

This change detects v4-mapped address on v6 sockets for the wildcard
case, and instead formats the TargetAddress response as an IPv4 address.

In order to not further complicate iscsit_build_sendtargets_response,
I've actually simplified it by moving the bracket wrapping of IPv6
address into iscsit_accept_np where local_ip and login_ip strings are
set.  That also simplifies iscsi_stat_tgt_attr_show_attr_fail_intr_addr.

Side effect of the string format change is that
lio_target_nacl_show_info will now print login_ip bracket wrapped for
IPv6 connections, as will a few debug prints.
Signed-off-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Changing this attribute to 0 will mean that all initiators that login
to the target while the target has generate_node_acls=1 will see all
TPG LUNs, which may be the desired behavior in some cases.

(nab: Apply patch without macro changes)
Reported-by: Craig Watson <craig.watson@vanguard-rugged.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

The usage of strict_strtoul() and strict_strtoull() is not preferred,
because strict_strtoul() and strict_strtoull() are obsolete. Thus,
kstrtoul() and kstrtoull() should be used.

v2: Fix incorrect return in ft_add_tpg (Fengguang)
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Pull SCSI fixes from James Bottomley:
 "This is three bug fixes: An fnic warning caused by sleeping under a
  lock, a major regression with our updated WRITE SAME/UNMAP logic which
  caused tons of USB devices (and one RAID card) to cease to function
  and a megaraid_sas firmware initialisation problem which causes kdump
  failures"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  [SCSI] Don't attempt to send extended INQUIRY command if skip_vpd_pages is set
  [SCSI] fnic: BUG: sleeping function called from invalid context during probe
  [SCSI] megaraid_sas: megaraid_sas driver init fails in kdump kernel

Pull powerpc fixes from Ben Herrenschmidt:
 "This includes small series from Michael Neuling to fix a couple of
  nasty remaining problems with the new Power8 support, also targeted at
  stable 3.10, without which some new userspace accessible registers
  aren't properly context switched, and in some case, can be clobbered
  by the user of transactional memory.

  Along with that, a few slightly more minor things, such as a missing
  Kconfig option to enable handling of denorm exceptions when not
  running under a hypervisor (or userspace will randomly crash when
  hitting denorms with the vector unit), some nasty bugs in the new
  pstore oops code, and other simple bug fixes worth having in now.

  Note: I picked up the two powerpc KVM fixes as Alex Graf asked me to
  handle KVM bits while he is on vacation.  However I'll let him decide
  whether they should go to -stable or not when he is back"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/tm: Fix context switching TAR, PPR and DSCR SPRs
  powerpc: Save the TAR register earlier
  powerpc: Fix context switch DSCR on POWER8
  powerpc: Rework setting up H/FSCR bit definitions
  powerpc: Fix hypervisor facility unavaliable vector number
  powerpc/kvm/book3s_pr: Return appropriate error when allocation fails
  powerpc/kvm: Add signed type cast for comparation
  powerpc/eeh: Add missing procfs entry for PowerNV
  powerpc/pseries: Add backward compatibilty to read old kernel oops-log
  powerpc/pseries: Fix buffer overflow when reading from pstore
  powerpc: On POWERNV enable PPC_DENORMALISATION by default

Pull s390 kvm fixes from Paolo Bonzini:
 "Two fixes for s390"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: s390: fix pfmf non-quiescing control handling
  KVM: s390: move kvm_guest_enter,exit closer to sie

Pull i2c fixes from Wolfram Sang:
 "Some driver bugfixes for the I2C subsystem"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: mv64xxx: Document the newly introduced allwinner compatible
  i2c: Fix Kontron PLD prescaler calculation
  i2c: i2c-mxs: Use DMA mode even for small transfers