So after kicking around commit 547ac4c9c90 around a bit more, a tcm_qla2xxx LUN
unlink OP has generated the following warning:

[   50.386625] qla2xxx [0000:07:00.0]-00af:0: Performing ISP error recovery - ha=ffff880263774000.
[   70.572988] qla2xxx [0000:07:00.0]-8038:0: Cable is unplugged...
[  126.527531] ------------[ cut here ]------------
[  126.532677] WARNING: at kernel/softirq.c:159 local_bh_enable_ip+0x41/0x8c()
[  126.540433] Hardware name: S5520HC
[  126.544248] Modules linked in: tcm_vhost ib_srpt ib_cm ib_sa ib_mad ib_core tcm_qla2xxx tcm_loop tcm_fc libfc iscsi_target_mod target_core_pscsi target_core_file target_core_iblock target_core_mod configfs ipv6 iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi dm_round_robin dm_multipath scsi_dh loop i2c_i801 kvm_intel kvm crc32c_intel i2c_core microcode joydev button iomemory_vsl(O) pcspkr ext3 jbd uhci_hcd lpfc ata_piix libata ehci_hcd qla2xxx mlx4_core scsi_transport_fc scsi_tgt igb [last unloaded: scsi_wait_scan]
[  126.595567] Pid: 3283, comm: unlink Tainted: G           O 3.5.0-rc2+ #33
[  126.603128] Call Trace:
[  126.605853]  [<ffffffff81026b91>] ? warn_slowpath_common+0x78/0x8c
[  126.612737]  [<ffffffff8102c342>] ? local_bh_enable_ip+0x41/0x8c
[  126.619433]  [<ffffffffa03582a2>] ? core_disable_device_list_for_node+0x70/0xe3 [target_core_mod]
[  126.629323]  [<ffffffffa035849f>] ? core_clear_lun_from_tpg+0x88/0xeb [target_core_mod]
[  126.638244]  [<ffffffffa0362ec1>] ? core_tpg_post_dellun+0x17/0x48 [target_core_mod]
[  126.646873]  [<ffffffffa03575ee>] ? core_dev_del_lun+0x26/0x8c [target_core_mod]
[  126.655114]  [<ffffffff810bcbd1>] ? dput+0x27/0x154
[  126.660549]  [<ffffffffa0359aa0>] ? target_fabric_port_unlink+0x3b/0x41 [target_core_mod]
[  126.669661]  [<ffffffffa034a698>] ? configfs_unlink+0xfc/0x14a [configfs]
[  126.677224]  [<ffffffff810b5979>] ? vfs_unlink+0x58/0xb7
[  126.683141]  [<ffffffff810b6ef3>] ? do_unlinkat+0xbb/0x142
[  126.689253]  [<ffffffff81330c75>] ? page_fault+0x25/0x30
[  126.695170]  [<ffffffff81335df9>] ? system_call_fastpath+0x16/0x1b
[  126.702053] ---[ end trace 2f8e5b0a9ec797ef ]---
[  126.756336] qla2xxx [0000:07:00.0]-00af:0: Performing ISP error recovery - ha=ffff880263774000.
[  146.942414] qla2xxx [0000:07:00.0]-8038:0: Cable is unplugged...

So this warning triggered because device_list disable logic is now
holding nacl->device_list_lock w/ spin_lock_irqsave before obtaining
port->sep_alua_lock with only spin_lock_bh..

The original disable logic obtains *deve ahead of dropping the entry
from deve->alua_port_list and then obtains ->device_list_lock to do the
remaining work.  Also, I'm pretty sure this particular warning is being
generated by a demo-mode session in tcm_qla2xxx, and not by explicit
NodeACL MappedLUNs.  The Initiator MappedLUNs are already protected by a
seperate configfs symlink reference back se_lun->lun_group, and the
demo-mode se_node_acl (and associated ->device_list[]) is released
during se_portal_group->tpg_group shutdown.

The following patch drops the extra functional change to disable logic
in commit 547ac4c9c90

Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Code was almost entirely divided based on value of bool param "enable".

Split it into two functions.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Bubble-up retval from iscsi_update_param_value() and
iscsit_ta_authentication().

Other very small retval cleanups.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Only used in a debugprint, and function signature is cleaner now.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The last functionality of the target processing thread is offloading possibly
long running task management requests from the submitter context.  To keep
TMR semantics the same we need a single threaded ordered queue, which can
be provided by a per-device workqueue with the right flags.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Remove this command submission path which is not used by any in-tree driver.
This also removes the now unused new_cmd_map fabtric method, which a few
drivers implemented despite never calling transport_generic_handle_cdb_map.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There is no need to schedule the delayed processing in a workqueue that
offloads it to the target processing thread.  Instead execute it directly
from the workqueue.  There will be a lot of future work in this area,
which I'd likfe to defer for now as it is not nessecary for getting rid
of the target processing thread.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Defer the write processing to the internal to be able to use
target_execute_cmd.  I'm not even entirely sure the calling code requires
this due to the convoluted structure in libfc, but let's be safe for now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Kiran Patil <Kiran.patil@intel.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Defer the whole tcm_qla2xxx_handle_data call instead of just the error
path to the qla2xxx-internal workqueue.  Also remove the useless lock around
the CMD_T_ABORTED check.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Cc: tcm-qla2xxx@qlogic.com
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

srpt_handle_rdma_comp is called from kthread context and thus can execute
target_execute_cmd directly.  srpt_abort_cmd sets the CMD_T_LUN_STOP
flag directly, and thus the abuse of transport_generic_handle_data can be
replaced with an opencoded variant of that code path.  I'm still not happy
about a fabric driver poking into target core internals like this, but
let's defer the bigger architecture changes for now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

All three callers of transport_generic_handle_data are from user context
and can use target_execute_cmd directly to handle the backend I/O submission
of WRITE I/O.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

When we call target_execute_cmd for write commands the command has been
on the state list before an abort might have come in before
target_execute_cmd.  Call transport_check_aborted_status to deal with
this case.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Just call target_execute_cmd directly.  Also, convert loopback, sbp,
usb-gadget to use the newly exported target_execute_cmd().
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Inline the transport_off == 0 case into target_execute_cmd to simplify
the function for the remaining cases.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

ctype.h and string.h header files were included more than once.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Existing lio_dump.py code expects this to be in place for /iscsi.

Revert for now to avoid userspace breakage in lio-utils

This reverts commit fd88a785f9ac5d6be437c528571ccd85cdf2d493.
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Having all the unmap payload parsing in the backed is a bit ugly, but until
more drivers support it and we can find a good interface for all of them
that seems the way to go.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add spc_ops->execute_write_same() caller for ->execute_cmd() setup,
and update IBLOCK backends to use it.

(nab: add export of spc_get_write_same_sectors symbol)
(roland: Carry forward: Fix range calculation in WRITE SAME emulation
         when num blocks == 0)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Add spc_ops->execute_sync_cache() caller for ->execute_cmd() setup,
and update IBLOCK + FILEIO backends to use it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Remove the execute_cmd method in struct se_subsystem_api, and always use the
one directly in struct se_cmd.  To make life simpler for SBC virtual backends
a struct spc_ops that is passed to sbc_parse_cmd is added.  For now it
only contains an execute_rw member, but more will follow with the subsequent
commits.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Remove the dead SCF_SE_ALLOW_EOO and SCF_DELAYED_CMD_FROM_SAM_ATTR
from se_cmd_flags_table.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It's got no callers...
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

see https://bugzilla.redhat.com/show_bug.cgi?id=818855

Adds a parameter so read-only block devices may be registered as
LIO backstores.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

These modules, along with other fabrics, should be loaded as-needed by
the LIO userspace tools.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Also remove the unused ref_task_lun field in struct se_tmr_req.

(nab: Add missing TASK_REASSIGN ref_lun vs. ref_cmd orig_fe_lun checks
      in iscsit_tmr_task_reassign)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Since "target: Drop se_device TCQ queue_depth usage from I/O path" we always
submit all commands (or back then, tasks) from __transport_execute_tasks.

That means the the execute list has lots its purpose, as we can simply
submit the commands that are restarted in transport_complete_task_attr
directly while we walk the list.  In fact doing so also solves a race
in the way it currently walks to delayed_cmd_list as well.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes back the pSCSI backend to follow pre 3.6-queue code to
passthrough SPC-3 persistent reservations + SPC-2 legacy reservation
handling to the underlying LLD / physical hardware.

For folks who really need this for their own SPC-3 emulation logic, avoid
changing the functionality of this beyond what is exported for REPORT_LUNS
for existing code, and to avoid problems with SPC-3 PR/ALUA as INQUIRY
EVPD=0x83 emulation needs to be in place in order for this to work as
expected with spc_parse_cdb() code..

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The MAINTENANCE_[IN,OUT] CDB parsing required for generic ALUA emulation
needs to be in spc_parse_cdb() to function for virtual TYPE_DISK exports,
instead of in backend pscsi_parse_cdb() code used only for passthrough ops.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The virtual drivers don't need to clear cdb fields they never look at, so move
this code into the pscsi backend.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Move the existing code in target_core_cdb.c into the files for the command
sets that the emulations implement.

(roland + nab: Squash patch: Fix range calculation in WRITE SAME emulation
 when num blocks == 0s)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Instead of trying to handle all SCSI command sets in one function
(transport_generic_cmd_sequencer) call out to the backend driver to perform
this functionality.  For pSCSI a copy of the existing code is used, but for
all virtual backends we can use a new parse_sbc_cdb helper is used to
provide a simple SBC emulation.

For now this setups means a fair amount of duplication between pSCSI and the
SBC library, but patches later in this series will sort out that problem.

(nab: Fix up build failure in target_core_pscsi.c)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

(nab: Add EXPORT_SYMBOL usage for spc_parse_cdb)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We don't need three flags to classifiy the CDB as we can check for a NULL S/G
list for a dataless command, and can infer from the absence of the data flag
that we deal with a control CDB.  Also remove the _SG_IO from the data CDB
flag as all I/O is dont on S/G lists now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Move all code not related to cdb parsing from transport_generic_cmd_sequencer
into target_setup_cmd_from_cdb.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

When NUMBER OF LOGICAL BLOCKS is 0, WRITE SAME is supposed to write
all the blocks from the specified LBA through the end of the device.
However, dev->transport->get_blocks(dev) (perhaps confusingly) returns
the last valid LBA rather than the number of blocks, so the correct
number of blocks to write starting with lba is

dev->transport->get_blocks(dev) - lba + 1

(nab: Backport roland's for-3.6 patch to for-3.5)
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Cc: Cc: <stable@vger.kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>