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2012-07-17target: Allow for target_submit_cmd() returning errorsRoland Dreier
We want it to be possible for target_submit_cmd() to return errors up to its fabric module callers. For now just update the prototype to return an int, and update all callers to handle non-zero return values as an error. This is immediately useful for tcm_qla2xxx to fix a long-standing active I/O session shutdown race, but tcm_fc, usb-gadget, and sbp-target the fabric maintainers need to check + ACK that handling a target_submit_cmd() failure due to session shutdown does not introduce regressions (nab: Respin against for-next after initial NACK + update docbook comment + fix double se_cmd init in exception path for usb-gadget) Cc: Chad Dupuis <chad.dupuis@qlogic.com> Cc: Arun Easi <arun.easi@qlogic.com> Cc: Chris Boot <bootc@bootc.net> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Mark Rustad <mark.d.rustad@intel.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Felipe Balbi <balbi@ti.com> Cc: Andy Grover <agrover@redhat.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: Add generation of LOGICAL BLOCK ADDRESS OUT OF RANGERoland Dreier
Many SCSI commands are defined to return a CHECK CONDITION / ILLEGAL REQUEST with ASC set to LOGICAL BLOCK ADDRESS OUT OF RANGE if the initiator sends a command that accesses a too-big LBA. Add an enum value and case entries so that target code can return this status. Signed-off-by: Roland Dreier <roland@purestorage.com> Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: Remove se_session.sess_wait_listRoland Dreier
Since we set se_session.sess_tearing_down and stop new commands from being added to se_session.sess_cmd_list before we wait for commands to finish when freeing a session, there's no need for a separate sess_wait_list -- if we let new commands be added to sess_cmd_list after setting sess_tearing_down, that would be a bug that breaks the logic of waiting in-flight commands. Also rename target_splice_sess_cmd_list() to target_sess_cmd_list_set_waiting(), since we are no longer splicing onto a separate list. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: Un-export target_get_sess_cmd()Roland Dreier
There are no in-tree users of target_get_sess_cmd() outside of target_core_transport.c. Any new code should use the higher-level target_submit_cmd() interface. So let's un-export target_get_sess_cmd() and make it static to the one file where it's actually used. (nab: Fix up minor fuzz to for-next) Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: replace the processing thread with a TMR work queueChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: remove transport_generic_handle_cdb_mapChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: remove transport_generic_handle_dataChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: remove transport_generic_process_writeChristoph Hellwig
Just call target_execute_cmd directly. Also, convert loopback, sbp, usb-gadget to use the newly exported target_execute_cmd(). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: move unmap to struct spc_opsChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: move write_same to struct spc_opsChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: move sync_cache to struct spc_opsChristoph Hellwig
Add spc_ops->execute_sync_cache() caller for ->execute_cmd() setup, and update IBLOCK + FILEIO backends to use it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: add struct spc_ops + initial ->execute_rw pointer usageChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: remove dead SCF_ flagsChristoph Hellwig
Remove the dead SCF_SE_ALLOW_EOO and SCF_DELAYED_CMD_FROM_SAM_ATTR from se_cmd_flags_table. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: move ref_cmd from the generic se_tmr_req into iscsi codeChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: remove the execute listChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: move code for CDB emulationChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: add a parse_cdb method to the backend driversChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16target: remove control CDB flagsChristoph Hellwig
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: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-06-12target: Add TFO->put_session() caller for HW fabric session shutdownJoern Engel
This patch adds an optional target_core_fabric_ops->put_session() caller within the existing target_put_session() code path. This is required by tcm_qla2xxx code in order to invoke it's own fabric specific session shutdown handler using se_session->sess_kref. Signed-off-by: Joern Engel <joern@logfs.org> Cc: Roland Dreier <roland@purestorage.com> Cc: Arun Easi <arun.easi@qlogic.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-17target: Add MI_REPORT_TARGET_PGS ext. header + implict_trans_secs attributeNicholas Bellinger
This patch adds support for ALUA MI_REPORT_TARGET_PGS extended header format defined within SPC-4. It changes target core ALUA emulation logic within target_emulate_report_target_port_groups() to support both the extended and original length only header formats. It includes adding a new 'implict_trans_secs' attribute for each ALUA target port group to control the value returned to the application client for an recommended implict translation timeout in seconds. By default this value is currently set to zero, and limited up to 255 by virtue of using a single byte in the extended header format. This value is used by target_emulate_report_target_port_groups() within the extended header logic to set IMPLICIT TRANSITION TIME as defined by spc4r30. Cc: Hannes Reinecke <hare@suse.de> Cc: Rob Evers <revers@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-11target: make target_put_session voidJörn Engel
No real change, it effectively already was. Signed-off-by: Joern Engel <joern@logfs.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-09target: Remove max_sectors device attribute for modern se_task less codeNicholas Bellinger
This patch removes the original usage of dev_attr->max_sectors in favor of dev_attr->hw_max_sectors that is now being enforced by target core from within transport_generic_cmd_sequencer() for SCF_SCSI_DATA_SG_IO_CDB ops. After the recent se_task removal patches from hch, this value for IBLOCK backends being set via configfs by userspace from an saved max_sectors value that is turning out to be problematic, so it makes sense to go ahead and remove this now legacy attribute all-together. This patch also continues to make se_dev_set_default_attribs() do (sectors / block_size) alignment for what actually get used by target_core_mod to be safe here, following the same alignment currently used by fabric_max_sectors. Reported-by: Andy Grover <agrover@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the t_se_count field in struct se_cmdChristoph Hellwig
Now that tasks are gone we are guaranteed to only get a single completion per command, and thus don't need this counter. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the t_task_cdbs_ex_left field in struct se_cmdChristoph Hellwig
Now that tasks are gone we are guaranteed to only get a single completion per command, and thus don't need this counter. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the t_task_cdbs_left field in struct se_cmdChristoph Hellwig
Now that tasks are gone we are guaranteed to only get a single completion per command, and thus don't need this counter. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove struct se_taskChristoph Hellwig
We can use struct se_cmd for everything it did. Make sure to pass the S/G list and data direction to the execution function to ease adding back BIDI support later on. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: move the state and execute lists to the commandChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: simplify command to task linkageChristoph Hellwig
Now that we only have a single task per command we can use a direct pointer to it instead of list. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: replace ->execute_task with ->execute_cmdChristoph Hellwig
Make CDB emulation work on commands instead of tasks again as a preparation of removing tasks completely. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the task_sectors field in struct se_taskChristoph Hellwig
Remove the task_sectors field that isn't used anywhere. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the task_size field in struct se_taskChristoph Hellwig
Now that we don't split commands the size field in the task is always equivalent to the one in the CDB, even in cases where we have two tasks due to a BIDI transfer. Just refer the the size in the command instead of duplicating it in the task. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove the task_lba field in struct se_taskChristoph Hellwig
Now that we don't split commands the lba field in the task is always equivalent to the one in the CDB, even in cases where we have two tasks due to a BIDI transfer. Just refer the the lba in the command instead of duplicating it in the task. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-05-06target: remove target_get_task_cdbChristoph Hellwig
Now that tasks are always the same size as the command there is no need to rewrite a CDB in common code. Notw that we keep the separately allocated CDB in the pscsi and stgt backends for now, to easy reintroducing any command splitting local to these backends if nessecary. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14target: Rename target_allocate_tasks to target_setup_cmd_from_cdbAndy Grover
This patch renames a horribly misnamed function that no longer allocate tasks to something more descriptive for it's modern use in target core. (nab: Fix up ib_srpt to use this as well ahead of a target_submit_cmd conversion) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14target: Remove transport_do_task_sg_chain() and associated detritusRoland Dreier
Now that all fabrics are converted over to using se_cmd->t_data_sg directly, we can drop the task sg chaining support. With the modern memory allocation in target core, task sg chaining is needless overhead -- we would split up the main cmd sglist into pieces, and then splice those pieces back together instead of just using the original list directly. Signed-off-by: Roland Dreier <roland@purestorage.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14target: add unknown size flag to target_submit_cmd()Sebastian Andrzej Siewior
The UASP protocol does not inform the target device upfront how much data it should expect so we have to learn in from the CDB. So in order to handle this case, add a TARGET_SCF_UNKNOWN_SIZE to target_submit_cmd() and perform an explictly assignment for se_cmd->data_length from the extracted CDB size in transport_generic_cmd_sequencer(). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14target: Remove obsolete DF_READ_ONLY usageNicholas Bellinger
This was used at one time as a hack by FILEIO backend registration to allow a struct block_device that was claimed with blkdev_get (by a local filesystem mount for example) to be exported as read-only (SCSI WP=1). Since FILEIO backend registration will no longer attempt to obtain exclusive access to an underlying struct block_device here, this flag is now obsolete. Reported-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-15target: Use array_zalloc for device_listJörn Engel
Turns an order-8 allocation into slab-sized ones, thereby preventing allocation failures with memory fragmentation. This likely saves memory as well, as the slab allocator can pack objects more tightly than the buddy allocator. (nab: Fix lio-core patch fuzz) Signed-off-by: Joern Engel <joern@logfs.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-15target: Use array_zalloc for tpg_lun_listJörn Engel
Turns an order-10 allocation into slab-sized ones, thereby preventing allocation failures with memory fragmentation. This likely saves memory as well, as the slab allocator can pack objects more tightly than the buddy allocator. Signed-off-by: Joern Engel <joern@logfs.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-10target: Bump core version to v4.1.0-rc2-ml + fabric versionsNicholas Bellinger
Bump core version to v4.1.0-rc2-ml, and for versions from the following mainline fabric modules: loopback: v2.1-rc2 tcm_fc: v0.4 iscsi-target: v4.1.0-rc2 Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-10target: Drop unused legacy target_core_fabric_ops API callersNicholas Bellinger
This patch drops the following unused legacy API callers from target_core_fabric.h: *) TFO->fall_back_to_erl0() *) TFO->stop_session() *) TFO->sess_logged_in() *) TFO->is_state_remove() This patch also removes the stub usage in loopback, tcm_fc, iscsi_target, and ib_srpt fabric modules. Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-10target: Convert se_node_acl->acl_group removal to use ->acl_krefNicholas Bellinger
This patch converts core_tpg_del_initiator_node_acl() shutdown from configfs context to use se_node_acl->acl_kref and ->acl_free_comp in order to wait for outstanding fabric callbacks to complete via transport_deregister_session() callbacks before waking ->acl_free_comp from the last ->acl_kref put. It also changes core_tpg_del_initiator_node_acl() to setup a local sess_list with target_get_session() + acl->acl_stop = 1 for active sessions that will be shutdown, and changes transport_deregister_session_configfs() to check for ->acl_stop usage. Cc: Roland Dreier <roland@purestorage.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Joern Engel <joern@logfs.org> Cc: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-10target: Add se_node_acl->acl_kref for ->acl_free_comp usageNicholas Bellinger
This patch adds se_node_acl->acl_kref for use with ->acl_free_comp during explict se_node_acl release. It adds kref_init() during se_node_acl setup, kref_get() during __transport_register_session() -> target_put_nacl() with existing transport_deregister_session() fabric callback usage. It also moves transport_free_session() to release *se_sess memory after target_put_nacl() execution in transport_deregister_session() Cc: Roland Dreier <roland@purestorage.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Joern Engel <joern@logfs.org> Cc: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-10target: Add se_node_acl->acl_free_comp for NodeACL release pathNicholas Bellinger
Add se_node_acl->acl_free_comp for NodeACL release path to wait for outstanding fabric session shutdown to complete in transport_deregister_session() before finishing NodeACL release from configfs process context. Also make transport_deregister_session() clear the comp_nacl bit to skip se_node_acl->acl_free_comp completion for dynamically generated NodeACL during fabric session shutdown. Cc: Roland Dreier <roland@purestorage.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Joern Engel <joern@logfs.org> Cc: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-03-10target: Add se_sess->sess_kref + get/put helpersNicholas Bellinger
This patch adds basic se_session->sess_kref and get/put helpers for fabric session reference counting. It sets the initial kref in transport_init_session() and adds a target_release_session() callback to invoke TFO->close_session() for final session shutdown. Cc: Roland Dreier <roland@purestorage.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Joern Engel <joern@logfs.org> Cc: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-02-25target: Allow target_submit_tmr interrupt context + pass ABORT_TASK tagNicholas Bellinger
This patch allows target_submit_tmr() to pass gfp_t for se_cmd->se_tmr_req allocation, and also set up se_cmd->se_tmr_req->ref_task_tag for passed tag with TMR_ABORT_TASK. Also update tcm_fc(fcoe) parameter usgae and add ref_task_tag FIXME for TMR_ABORT_TASK usage, Cc: Andy Grover <agrover@redhat.com> Cc: Kiran Patil <kiran.patil@intel.com> Cc: Arun Easi <arun.easi@qlogic.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-02-25target: Fix target_submit_tmr se_tmr_req allocation failuresNicholas Bellinger
This patch makes target_submit_tmr() se_tmr_req allocation occur before target_get_sess_cmd(), and changes target_submit_tmr() to return a failure w/ non zero status to the fabric caller upon core_tmr_alloc_req() failure. Cc: Andy Grover <agrover@redhat.com> Cc: Kiran Patil <kiran.patil@intel.com> Cc: Arun Easi <arun.easi@qlogic.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-02-25target: Untangle front-end and back-end meanings of max_sectors attributeRoland Dreier
se_dev_attrib.max_sectors currently has two independent meanings: - It is reported in the block limits VPD page as the maximum transfer length, ie the largest IO that the front-end (fabric) can handle. Also the target core doesn't enforce this maximum transfer length. - It is used to hold the size of the largest IO that the back-end can handle, so we know when to split SCSI commands into multiple tasks. Fix this by adding a new se_dev_attrib.fabric_max_sectors to hold the maximum transfer length, and checking incoming IOs against that limit. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-02-25target: Fix up handling of short INQUIRY buffersRoland Dreier
If the initiator sends us an INQUIRY command with an allocation length that's shorter than what we want to return, we're simply supposed to truncate our response and return what the initiator gave us space for, without signaling any error. Current target code has various tests that don't fill out the full response if the buffer is too short and sometimes return errors incorrectly. Fix this up by allocating a bounce buffer for INQUIRY responses if we need to, ie if we have cmd->data_length too small as well as SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC set in cmd->se_cmd_flags -- for most fabrics, we always allocate at least a full page, but for tcm_loop we may have a small buffer coming directly from the SCSI stack. This lets us delete a lot of cmd->data_length checking, and also makes our INQUIRY handling correct per SPC in a lot more cases. Signed-off-by: Roland Dreier <roland@purestorage.com> Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-02-25target: Add SCF_ACK_KREF flag for acknowledgement krefNicholas Bellinger
When TARGET_SCF_ACK_KREF is in use with target_submit_cmd() for setting the extra acknowledgement reference to se_cmd->cmd_kref, go ahead and set SCF_ACK_KREF in order to be used later by abort task. Reported-by: Roland Dreier <roland@purestorage.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>