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: NNicholas 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: NChristoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NNicholas 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: NNicholas 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: NNicholas 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: NNicholas 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: NNicholas 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: NNicholas Bellinger <nab@daterainc.com>

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: NAsias He <asias@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The return value wasn't checked by any of the callers.  Assuming this is
correct behaviour, we can simplify some code by not bothering to
generate it.

nab: Add srpt_queue_data_in() + srpt_queue_tm_rsp() nops around
     srpt_queue_response() void return
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Three have been checked for but were never set.  Remove the dead code.
Also renumbers the remaining ones to a) get rid of the holes after the
removal and b) avoid a collision between TMR_FUNCTION_COMPLETE==0 and
the uninitialized case.  If we failed to set a code, we should rather
fall into the default case then return success.
Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch addresses a bug where RDMA_CM_EVENT_DISCONNECTED may occur
before the connection shutdown has been completed by rx/tx threads,
that causes isert_free_conn() to wait indefinately on ->conn_wait.

This patch allows isert_disconnect_work code to invoke rdma_disconnect
when isert_disconnect_work() process context is started by client
session reset before isert_free_conn() code has been reached.

It also adds isert_conn->conn_mutex protection for ->state within
isert_disconnect_work(), isert_cq_comp_err() and isert_free_conn()
code, along with isert_check_state() for wait_event usage.

(v2: Add explicit iscsit_cause_connection_reinstatement call
     during isert_disconnect_work() to force conn reset)

Cc: stable@vger.kernel.org  # 3.10+
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch moves ISCSI_OP_REJECT failures into iscsit_sequence_cmd()
in order to avoid external iscsit_reject_cmd() reject usage for all
PDU types.

It also updates PDU specific handlers for traditional iscsi-target
code to not reset the session after posting a ISCSI_OP_REJECT during
setup.

(v2: Fix CMDSN_LOWER_THAN_EXP for ISCSI_OP_SCSI to call
     target_put_sess_cmd() after iscsit_sequence_cmd() failure)

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: stable@vger.kernel.org  # 3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes iscsit_add_reject() + iscsit_add_reject_from_cmd()
usage to not sleep on iscsi_cmd->reject_comp to address a free-after-use
usage bug in v3.10 with iser-target code.

It saves ->reject_reason for use within iscsit_build_reject() so the
correct value for both transport cases.  It also drops the legacy
fail_conn parameter usage throughput iscsi-target code and adds
two iscsit_add_reject_cmd() and iscsit_reject_cmd helper functions,
along with various small cleanups.

(v2: Re-enable target_put_sess_cmd() to be called from
     iscsit_add_reject_from_cmd() for rejects invoked after
     target_get_sess_cmd() has been called)

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: stable@vger.kernel.org  # 3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds an optional /auth/ configfs group to TPG context that
can be used by fabrics like iscsi-target for TPG demo-mode
authentication.

Cc: Dax Kelson <dkelson@gurulabs.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch refactoring existing iscsit_send_text_rsp() in order
to handle iscsi_text_rsp payloads in a transport specific manner.

This includes the addition of iscsit_build_text_rsp() to build
the response payload and initialize ISCSI_OP_TEXT_RSP.

v2: Make iscsit_build_text_rsp() determine extra padding bytes, and
    drop legacy padding calculation for traditional iSCSI text
    responses within iscsit_send_text_rsp()
Reported-by: NOr Gerlitz <ogerlitz@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch refactors ISCSI_OP_TEXT handling within iscsi-target in
order to handle iscsi_text payloads in a transport specific manner.

This includes splitting current iscsit_handle_text_cmd() into
iscsit_setup_text_cmd() and iscsit_process_text_cmd() calls, and
makes iscsit_handle_text_cmd be only used internally by traditional
iscsi socket calls.

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch refactors ISCSI_OP_NOOP handling within iscsi-target in
order to handle iscsi_nopout payloads in a transport specific manner.

This includes splitting existing iscsit_handle_nop_out() into
iscsit_setup_nop_out() and iscsit_process_nop_out() calls, and
makes iscsit_handle_nop_out() be only used internally by traditional
iscsi socket calls.

Next update iser-target code to use new callers and add FIXME for
the handling iscsi_nopout payloads.  Also fix reject response handling
in iscsit_setup_nop_out() to use proper iscsit_add_reject_from_cmd().

v2: Fix uninitialized iscsit_handle_nop_out() payload_length usage (Fengguang)
v3: Remove left-over dead code in iscsit_setup_nop_out() (DanC)
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Now with iscsi-target using modern se_cmd->cmd_kref accounting in
v3.10 code, it's safe to go ahead and drop the legacy release
codepath + se_cmd->check_release bit in transport_release_cmd()

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Moussa Ba <moussaba@micron.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch removes legacy se_cmd->t_fe_count usage in order to avoid
se_cmd->t_state_lock access within transport_put_cmd() during normal
fast path se_cmd descriptor release.

Also drop the left-over parameter usage within core_tmr_handle_tas_abort()

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Moussa Ba <moussaba@micron.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Instead of taking the buffer and length, update_and_write_aptpl() will
allocate the buffer as needed, and then free it. Instead, the function
takes an 'aptpl' boolean parameter.

This enables us to remove memory alloc/frees from struct
t10_pr_registration and other spots.

There is a slight loss of functionality because each callsite doesn't get
its own pr_debug any more, but this info can be cleaned via ftrace if
necessary and I think the shorter code is worth it.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It's only ever set to PR_APTPL_BUF_LEN, so we don't need a variable.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Go ahead and propigate up the ->cmd_kref put return value from
target_put_sess_cmd() -> transport_release_cmd() -> transport_put_cmd()
-> transport_generic_free_cmd().

This is useful for certain fabrics when determining the active I/O
shutdown case with SCF_ACK_KREF where a final target_put_sess_cmd()
is still required by the caller.
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Switch back to pre commit 1c7b13fe list splicing logic for active I/O
shutdown with tcm_qla2xxx + ib_srpt fabrics.

The original commit was done under the incorrect assumption that it's safe to
walk se_sess->sess_cmd_list unprotected in target_wait_for_sess_cmds() after
sess->sess_tearing_down = 1 has been set by target_sess_cmd_list_set_waiting()
during session shutdown.

So instead of adding sess->sess_cmd_lock protection around sess->sess_cmd_list
during target_wait_for_sess_cmds(), switch back to sess->sess_wait_list to
allow wait_for_completion() + TFO->release_cmd() to occur without having to
walk ->sess_cmd_list after the list_splice.

Also add a check to exit if target_sess_cmd_list_set_waiting() has already
been called, and add a WARN_ON to check for any fabric bug where new se_cmds
are added to sess->sess_cmd_list after sess->sess_tearing_down = 1 has already
been set.

Cc: Joern Engel <joern@logfs.org>
Cc: Roland Dreier <roland@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Drop unused transport_wait_for_tasks() check in target_wait_for_sess_cmds
shutdown code, and convert tcm_qla2xxx + ib_srpt fabric drivers.

Cc: Joern Engel <joern@logfs.org>
Cc: Roland Dreier <roland@kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NJoern Engel <joern@logfs.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Some were incremented, but never used anywhere from what I could tell.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add basic struct iscsit_transport API template to allow iscsi-target for
running with external transport modules using existing iscsi_target_core.h
code.

For all external modules, this calls try_module_get() and module_put()
to obtain + release an external iscsit_transport module reference count.

Also include the iscsi-target symbols necessary in iscsi_transport.h to
allow external transport modules to function.

v3 changes:
- Add iscsit_build_reject export for ISTATE_SEND_REJECT usage

v2 changes:

- Drop unnecessary export of iscsit_get_transport + iscsit_put_transport (roland)
- Add ->iscsit_queue_data_in() to remove extra context switch on RDMA_WRITE
- Add ->iscsit_queue_status() to remove extra context switch on IB_SEND status
- Add ->iscsit_get_dataout() to remove extra context switch on RDMA_READ
- Drop ->iscsit_free_cmd()
- Drop ->iscsit_unmap_cmd()
- Rename iscsit_create_transport() -> iscsit_register_transport() (andy)
- Rename iscsit_destroy_transport() -> iscsit_unregister_transport() (andy)
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Export target_get_sess_cmd() symbol so that it can be used by
iscsi-target.
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

iblock_execute_unmap() and fd_execute_unmap share a lot of code.
Add sbc_execute_unmap() helper to remove duplicated code for
iblock_execute_unmap() and fd_execute_unmap().

Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Trivial, but WRITE SAME is an SBC command so it seems strange for a
related function (defined in target_core_sbc.c) to be in the spc_
namespace.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

SBC-3 (revision 35) says:

    The PARAMETER LIST LENGTH field specifies the length in bytes of the
    UNMAP parameter list that is available to be transferred from the
    Data-Out Buffer. If the parameter list length is greater than zero
    and less than 0008h (i.e., eight), then the device server shall
    terminate the command with CHECK CONDITION status with the sense key
    set to ILLEGAL REQUEST and the additional sense code set to
    PARAMETER LIST LENGTH ERROR. A PARAMETER LIST LENGTH set to zero
    specifies that no data shall be sent.

so our sense code for too-short descriptors was wrong, and we were
incorrectly failing commands that didn't transfer any descriptors.

While we're at it, also handle the UNMAP check:

    If the ANCHOR bit is set to one, and the ANC_SUP bit in the Logical
    Block Provisioning VPD page (see 6.6.4) is set to zero, then the
    device server shall terminate the command with CHECK CONDITION
    status with the sense key set to ILLEGAL REQUEST and the additional
    sense code set to INVALID FIELD IN CDB.

(chris boot: Fix wrong cut+paste comment in transport_send_check_condition_and_sense)
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes LIO to use the configfs backend device name as the
model if you echo '1' to an individual device's emulate_model_alias attribute.
This is a valid operation only on devices with an export count of 0.
Signed-off-by: NTregaron Bayly <tbayly@bluehost.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch allows IBLOCK to check block hints in request_queue->flush_flags
when reporting current backend device WriteCacheEnabled status to a remote
SCSI initiator port.

This is done via a se_subsystem_api->get_write_cache() call instead of a
backend se_device creation time flag, as we expect REQ_FLUSH bits to possibly
change from an underlying blk_queue_flush() by the SCSI disk driver, or
internal raw struct block_device driver usage.

Also go ahead and update iblock_execute_rw() bio I/O path code to use
REQ_FLUSH + REQ_FUA hints when determining WRITE_FUA usage, and make SPC
emulation code use a spc_check_dev_wce() helper to handle both types of
cases for virtual backend subsystem drivers.

(asias: Drop unnecessary comparsion operators)
Reported-by: Nmajianpeng <majianpeng@gmail.com>
Cc: majianpeng <majianpeng@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

"buf" is 128 characters and "vpd->device_identifier" is 256.  It makes
the static checkers complain.

Also bump VPD_TMP_BUF_SIZE to match INQUIRY_VPD_DEVICE_IDENTIFIER_LEN.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Some target drivers might need to access the inquiry data
directly, without sending out the actual command.
So export these functions.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Cc: Nicholas Bellinger <nab@risingtidesystems.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Introduce TCM_NO_SENSE, mapping to sense code
'Not ready, no additional sense information'.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Cc: Nicholas Bellinger <nab@risingtidesystems.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Thanks for reviews, looking a lot better.

---- 8< ----

Initiator access config could be easier. The way other storage vendors
have addressed this is to support initiator groups: the admin adds
initiator WWNs to the group, and then LUN permissions can be granted for
the entire group at once.

Instead of changing ktarget's configfs interface, this patch keeps
the configfs interface per-initiator-wwn and just adds a 'tag' field
for each. This should be enough for user tools like targetcli to group
initiator ACLs and sync their configurations.

acl_tag is not used internally, but needs to be kept in configfs so that
all user tools can avoid dependencies on each other.

Code tested to work, although userspace pieces still to be implemented.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds [dev,lun]_link_magic value assignment + checks within generic
target_fabric_port_link() and target_fabric_mappedlun_link() code to ensure
destination config_item *target_item sent from configfs_symlink() ->
config_item_operations->allow_link() is the underlying se_device->dev_group
and se_lun->lun_group that we expect to symlink.
Reported-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We already expect TFO->get_blocks() to return sector_t for zero value case
when doing WRITE_SAME to the end of the backend device, so go ahead and return
sector_t from spc_get_write_same_sectors() to handle this case properly.

Also, update the single iblock_execute_write_same() caller of this code.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>