Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

4 files changed, 1204 insertions, 0 deletions

diff --git a/drivers/target/loopback/Kconfig b/drivers/target/loopback/Kconfig
new file mode 100644
index 000000000..f40f31607
--- /dev/null
+++ b/drivers/target/loopback/Kconfig
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config LOOPBACK_TARGET
+	tristate "TCM Virtual SAS target and Linux/SCSI LDD fabric loopback module"
+	depends on SCSI
+	help
+	  Say Y here to enable the TCM Virtual SAS target and Linux/SCSI LLD
+	  fabric loopback module.
diff --git a/drivers/target/loopback/Makefile b/drivers/target/loopback/Makefile
new file mode 100644
index 000000000..336bd44bf
--- /dev/null
+++ b/drivers/target/loopback/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_LOOPBACK_TARGET)	+= tcm_loop.o
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
new file mode 100644
index 000000000..d29830b95
--- /dev/null
+++ b/drivers/target/loopback/tcm_loop.c
@@ -0,0 +1,1141 @@
+/*******************************************************************************
+ *
+ * This file contains the Linux/SCSI LLD virtual SCSI initiator driver
+ * for emulated SAS initiator ports
+ *
+ * © Copyright 2011-2013 Datera, Inc.
+ *
+ * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
+ *
+ * Author: Nicholas A. Bellinger <nab@risingtidesystems.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ ****************************************************************************/
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/configfs.h>
+#include <linux/blk-mq.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_tcq.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_cmnd.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_fabric.h>
+
+#include "tcm_loop.h"
+
+#define to_tcm_loop_hba(hba)	container_of(hba, struct tcm_loop_hba, dev)
+
+static struct kmem_cache *tcm_loop_cmd_cache;
+
+static int tcm_loop_hba_no_cnt;
+
+static int tcm_loop_queue_status(struct se_cmd *se_cmd);
+
+static unsigned int tcm_loop_nr_hw_queues = 1;
+module_param_named(nr_hw_queues, tcm_loop_nr_hw_queues, uint, 0644);
+
+static unsigned int tcm_loop_can_queue = 1024;
+module_param_named(can_queue, tcm_loop_can_queue, uint, 0644);
+
+static unsigned int tcm_loop_cmd_per_lun = 1024;
+module_param_named(cmd_per_lun, tcm_loop_cmd_per_lun, uint, 0644);
+
+/*
+ * Called from struct target_core_fabric_ops->check_stop_free()
+ */
+static int tcm_loop_check_stop_free(struct se_cmd *se_cmd)
+{
+	return transport_generic_free_cmd(se_cmd, 0);
+}
+
+static void tcm_loop_release_cmd(struct se_cmd *se_cmd)
+{
+	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
+				struct tcm_loop_cmd, tl_se_cmd);
+	struct scsi_cmnd *sc = tl_cmd->sc;
+
+	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
+		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
+	else
+		scsi_done(sc);
+}
+
+static int tcm_loop_show_info(struct seq_file *m, struct Scsi_Host *host)
+{
+	seq_puts(m, "tcm_loop_proc_info()\n");
+	return 0;
+}
+
+static int tcm_loop_driver_probe(struct device *);
+static void tcm_loop_driver_remove(struct device *);
+
+static const struct bus_type tcm_loop_lld_bus = {
+	.name			= "tcm_loop_bus",
+	.probe			= tcm_loop_driver_probe,
+	.remove			= tcm_loop_driver_remove,
+};
+
+static struct device_driver tcm_loop_driverfs = {
+	.name			= "tcm_loop",
+	.bus			= &tcm_loop_lld_bus,
+};
+/*
+ * Used with root_device_register() in tcm_loop_alloc_core_bus() below
+ */
+static struct device *tcm_loop_primary;
+
+static void tcm_loop_target_queue_cmd(struct tcm_loop_cmd *tl_cmd)
+{
+	struct se_cmd *se_cmd = &tl_cmd->tl_se_cmd;
+	struct scsi_cmnd *sc = tl_cmd->sc;
+	struct tcm_loop_nexus *tl_nexus;
+	struct tcm_loop_hba *tl_hba;
+	struct tcm_loop_tpg *tl_tpg;
+	struct scatterlist *sgl_bidi = NULL;
+	u32 sgl_bidi_count = 0, transfer_length;
+
+	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
+	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
+
+	/*
+	 * Ensure that this tl_tpg reference from the incoming sc->device->id
+	 * has already been configured via tcm_loop_make_naa_tpg().
+	 */
+	if (!tl_tpg->tl_hba) {
+		set_host_byte(sc, DID_NO_CONNECT);
+		goto out_done;
+	}
+	if (tl_tpg->tl_transport_status == TCM_TRANSPORT_OFFLINE) {
+		set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
+		goto out_done;
+	}
+	tl_nexus = tl_tpg->tl_nexus;
+	if (!tl_nexus) {
+		scmd_printk(KERN_ERR, sc,
+			    "TCM_Loop I_T Nexus does not exist\n");
+		set_host_byte(sc, DID_ERROR);
+		goto out_done;
+	}
+
+	transfer_length = scsi_transfer_length(sc);
+	if (!scsi_prot_sg_count(sc) &&
+	    scsi_get_prot_op(sc) != SCSI_PROT_NORMAL) {
+		se_cmd->prot_pto = true;
+		/*
+		 * loopback transport doesn't support
+		 * WRITE_GENERATE, READ_STRIP protection
+		 * information operations, go ahead unprotected.
+		 */
+		transfer_length = scsi_bufflen(sc);
+	}
+
+	se_cmd->tag = tl_cmd->sc_cmd_tag;
+	target_init_cmd(se_cmd, tl_nexus->se_sess, &tl_cmd->tl_sense_buf[0],
+			tl_cmd->sc->device->lun, transfer_length,
+			TCM_SIMPLE_TAG, sc->sc_data_direction, 0);
+
+	if (target_submit_prep(se_cmd, sc->cmnd, scsi_sglist(sc),
+			       scsi_sg_count(sc), sgl_bidi, sgl_bidi_count,
+			       scsi_prot_sglist(sc), scsi_prot_sg_count(sc),
+			       GFP_ATOMIC))
+		return;
+
+	target_submit(se_cmd);
+	return;
+
+out_done:
+	scsi_done(sc);
+}
+
+/*
+ * ->queuecommand can be and usually is called from interrupt context, so
+ * defer the actual submission to a workqueue.
+ */
+static enum scsi_qc_status tcm_loop_queuecommand(struct Scsi_Host *sh,
+						 struct scsi_cmnd *sc)
+{
+	struct tcm_loop_cmd *tl_cmd = scsi_cmd_priv(sc);
+
+	pr_debug("%s() %d:%d:%d:%llu got CDB: 0x%02x scsi_buf_len: %u\n",
+		 __func__, sc->device->host->host_no, sc->device->id,
+		 sc->device->channel, sc->device->lun, sc->cmnd[0],
+		 scsi_bufflen(sc));
+
+	memset(tl_cmd, 0, sizeof(*tl_cmd));
+	tl_cmd->sc = sc;
+	tl_cmd->sc_cmd_tag = blk_mq_unique_tag(scsi_cmd_to_rq(sc));
+
+	tcm_loop_target_queue_cmd(tl_cmd);
+	return 0;
+}
+
+/*
+ * Called from SCSI EH process context to issue a LUN_RESET TMR
+ * to struct scsi_device
+ */
+static int tcm_loop_issue_tmr(struct tcm_loop_tpg *tl_tpg,
+			      u64 lun, int task, enum tcm_tmreq_table tmr)
+{
+	struct se_cmd *se_cmd;
+	struct se_session *se_sess;
+	struct tcm_loop_nexus *tl_nexus;
+	struct tcm_loop_cmd *tl_cmd;
+	int ret = TMR_FUNCTION_FAILED, rc;
+
+	/*
+	 * Locate the tl_nexus and se_sess pointers
+	 */
+	tl_nexus = tl_tpg->tl_nexus;
+	if (!tl_nexus) {
+		pr_err("Unable to perform device reset without active I_T Nexus\n");
+		return ret;
+	}
+
+	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_KERNEL);
+	if (!tl_cmd)
+		return ret;
+
+	init_completion(&tl_cmd->tmr_done);
+
+	se_cmd = &tl_cmd->tl_se_cmd;
+	se_sess = tl_tpg->tl_nexus->se_sess;
+
+	rc = target_submit_tmr(se_cmd, se_sess, tl_cmd->tl_sense_buf, lun,
+			       NULL, tmr, GFP_KERNEL, task,
+			       TARGET_SCF_ACK_KREF);
+	if (rc < 0)
+		goto release;
+	wait_for_completion(&tl_cmd->tmr_done);
+	ret = se_cmd->se_tmr_req->response;
+	target_put_sess_cmd(se_cmd);
+
+out:
+	return ret;
+
+release:
+	kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
+	goto out;
+}
+
+static int tcm_loop_abort_task(struct scsi_cmnd *sc)
+{
+	struct tcm_loop_hba *tl_hba;
+	struct tcm_loop_tpg *tl_tpg;
+	int ret;
+
+	/*
+	 * Locate the tcm_loop_hba_t pointer
+	 */
+	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
+	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
+	ret = tcm_loop_issue_tmr(tl_tpg, sc->device->lun,
+				 blk_mq_unique_tag(scsi_cmd_to_rq(sc)),
+				 TMR_ABORT_TASK);
+	return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
+}
+
+/*
+ * Called from SCSI EH process context to issue a LUN_RESET TMR
+ * to struct scsi_device
+ */
+static int tcm_loop_device_reset(struct scsi_cmnd *sc)
+{
+	struct tcm_loop_hba *tl_hba;
+	struct tcm_loop_tpg *tl_tpg;
+	int ret;
+
+	/*
+	 * Locate the tcm_loop_hba_t pointer
+	 */
+	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
+	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
+
+	ret = tcm_loop_issue_tmr(tl_tpg, sc->device->lun,
+				 0, TMR_LUN_RESET);
+	return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
+}
+
+static const struct scsi_host_template tcm_loop_driver_template = {
+	.show_info		= tcm_loop_show_info,
+	.proc_name		= "tcm_loopback",
+	.name			= "TCM_Loopback",
+	.queuecommand		= tcm_loop_queuecommand,
+	.change_queue_depth	= scsi_change_queue_depth,
+	.eh_abort_handler = tcm_loop_abort_task,
+	.eh_device_reset_handler = tcm_loop_device_reset,
+	.this_id		= -1,
+	.sg_tablesize		= 256,
+	.max_sectors		= 0xFFFF,
+	.dma_boundary		= PAGE_SIZE - 1,
+	.module			= THIS_MODULE,
+	.track_queue_depth	= 1,
+	.cmd_size		= sizeof(struct tcm_loop_cmd),
+};
+
+static int tcm_loop_driver_probe(struct device *dev)
+{
+	struct tcm_loop_hba *tl_hba;
+	struct Scsi_Host *sh;
+	int error, host_prot;
+
+	tl_hba = to_tcm_loop_hba(dev);
+
+	sh = scsi_host_alloc(&tcm_loop_driver_template,
+			sizeof(struct tcm_loop_hba));
+	if (!sh) {
+		pr_err("Unable to allocate struct scsi_host\n");
+		return -ENODEV;
+	}
+	tl_hba->sh = sh;
+
+	/*
+	 * Assign the struct tcm_loop_hba pointer to struct Scsi_Host->hostdata
+	 */
+	*((struct tcm_loop_hba **)sh->hostdata) = tl_hba;
+	/*
+	 * Setup single ID, Channel and LUN for now..
+	 */
+	sh->max_id = 2;
+	sh->max_lun = 0;
+	sh->max_channel = 0;
+	sh->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
+	sh->nr_hw_queues = tcm_loop_nr_hw_queues;
+	sh->can_queue = tcm_loop_can_queue;
+	sh->cmd_per_lun = tcm_loop_cmd_per_lun;
+
+	host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
+		    SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
+		    SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
+
+	scsi_host_set_prot(sh, host_prot);
+	scsi_host_set_guard(sh, SHOST_DIX_GUARD_CRC);
+
+	error = scsi_add_host(sh, &tl_hba->dev);
+	if (error) {
+		pr_err("%s: scsi_add_host failed\n", __func__);
+		scsi_host_put(sh);
+		tl_hba->sh = NULL;
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static void tcm_loop_driver_remove(struct device *dev)
+{
+	struct tcm_loop_hba *tl_hba;
+	struct Scsi_Host *sh;
+
+	tl_hba = to_tcm_loop_hba(dev);
+	sh = tl_hba->sh;
+
+	if (sh) {
+		scsi_remove_host(sh);
+		scsi_host_put(sh);
+	}
+}
+
+static void tcm_loop_release_adapter(struct device *dev)
+{
+	struct tcm_loop_hba *tl_hba = to_tcm_loop_hba(dev);
+
+	kfree(tl_hba);
+}
+
+/*
+ * Called from tcm_loop_make_scsi_hba() in tcm_loop_configfs.c
+ */
+static int tcm_loop_setup_hba_bus(struct tcm_loop_hba *tl_hba, int tcm_loop_host_id)
+{
+	int ret;
+
+	tl_hba->dev.bus = &tcm_loop_lld_bus;
+	tl_hba->dev.parent = tcm_loop_primary;
+	tl_hba->dev.release = &tcm_loop_release_adapter;
+	dev_set_name(&tl_hba->dev, "tcm_loop_adapter_%d", tcm_loop_host_id);
+
+	ret = device_register(&tl_hba->dev);
+	if (ret) {
+		pr_err("device_register() failed for tl_hba->dev: %d\n", ret);
+		put_device(&tl_hba->dev);
+		return -ENODEV;
+	}
+
+	if (!tl_hba->sh) {
+		device_unregister(&tl_hba->dev);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/*
+ * Called from tcm_loop_fabric_init() in tcl_loop_fabric.c to load the emulated
+ * tcm_loop SCSI bus.
+ */
+static int tcm_loop_alloc_core_bus(void)
+{
+	int ret;
+
+	tcm_loop_primary = root_device_register("tcm_loop_0");
+	if (IS_ERR(tcm_loop_primary)) {
+		pr_err("Unable to allocate tcm_loop_primary\n");
+		return PTR_ERR(tcm_loop_primary);
+	}
+
+	ret = bus_register(&tcm_loop_lld_bus);
+	if (ret) {
+		pr_err("bus_register() failed for tcm_loop_lld_bus\n");
+		goto dev_unreg;
+	}
+
+	ret = driver_register(&tcm_loop_driverfs);
+	if (ret) {
+		pr_err("driver_register() failed for tcm_loop_driverfs\n");
+		goto bus_unreg;
+	}
+
+	pr_debug("Initialized TCM Loop Core Bus\n");
+	return ret;
+
+bus_unreg:
+	bus_unregister(&tcm_loop_lld_bus);
+dev_unreg:
+	root_device_unregister(tcm_loop_primary);
+	return ret;
+}
+
+static void tcm_loop_release_core_bus(void)
+{
+	driver_unregister(&tcm_loop_driverfs);
+	bus_unregister(&tcm_loop_lld_bus);
+	root_device_unregister(tcm_loop_primary);
+
+	pr_debug("Releasing TCM Loop Core BUS\n");
+}
+
+static inline struct tcm_loop_tpg *tl_tpg(struct se_portal_group *se_tpg)
+{
+	return container_of(se_tpg, struct tcm_loop_tpg, tl_se_tpg);
+}
+
+static char *tcm_loop_get_endpoint_wwn(struct se_portal_group *se_tpg)
+{
+	/*
+	 * Return the passed NAA identifier for the Target Port
+	 */
+	return &tl_tpg(se_tpg)->tl_hba->tl_wwn_address[0];
+}
+
+static u16 tcm_loop_get_tag(struct se_portal_group *se_tpg)
+{
+	/*
+	 * This Tag is used when forming SCSI Name identifier in EVPD=1 0x83
+	 * to represent the SCSI Target Port.
+	 */
+	return tl_tpg(se_tpg)->tl_tpgt;
+}
+
+/*
+ * Returning (1) here allows for target_core_mod struct se_node_acl to be generated
+ * based upon the incoming fabric dependent SCSI Initiator Port
+ */
+static int tcm_loop_check_demo_mode(struct se_portal_group *se_tpg)
+{
+	return 1;
+}
+
+static int tcm_loop_check_prot_fabric_only(struct se_portal_group *se_tpg)
+{
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg, struct tcm_loop_tpg,
+						   tl_se_tpg);
+	return tl_tpg->tl_fabric_prot_type;
+}
+
+static u32 tcm_loop_sess_get_index(struct se_session *se_sess)
+{
+	return 1;
+}
+
+static int tcm_loop_get_cmd_state(struct se_cmd *se_cmd)
+{
+	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
+			struct tcm_loop_cmd, tl_se_cmd);
+
+	return tl_cmd->sc_cmd_state;
+}
+
+static int tcm_loop_write_pending(struct se_cmd *se_cmd)
+{
+	/*
+	 * Since Linux/SCSI has already sent down a struct scsi_cmnd
+	 * sc->sc_data_direction of DMA_TO_DEVICE with struct scatterlist array
+	 * memory, and memory has already been mapped to struct se_cmd->t_mem_list
+	 * format with transport_generic_map_mem_to_cmd().
+	 *
+	 * We now tell TCM to add this WRITE CDB directly into the TCM storage
+	 * object execution queue.
+	 */
+	target_execute_cmd(se_cmd);
+	return 0;
+}
+
+static int tcm_loop_queue_data_or_status(const char *func,
+		struct se_cmd *se_cmd, u8 scsi_status)
+{
+	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
+				struct tcm_loop_cmd, tl_se_cmd);
+	struct scsi_cmnd *sc = tl_cmd->sc;
+
+	pr_debug("%s() called for scsi_cmnd: %p cdb: 0x%02x\n",
+		 func, sc, sc->cmnd[0]);
+
+	if (se_cmd->sense_buffer &&
+	   ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
+	    (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
+
+		memcpy(sc->sense_buffer, se_cmd->sense_buffer,
+				SCSI_SENSE_BUFFERSIZE);
+		sc->result = SAM_STAT_CHECK_CONDITION;
+	} else
+		sc->result = scsi_status;
+
+	set_host_byte(sc, DID_OK);
+	if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
+	    (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
+		scsi_set_resid(sc, se_cmd->residual_count);
+	return 0;
+}
+
+static int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
+{
+	return tcm_loop_queue_data_or_status(__func__, se_cmd, SAM_STAT_GOOD);
+}
+
+static int tcm_loop_queue_status(struct se_cmd *se_cmd)
+{
+	return tcm_loop_queue_data_or_status(__func__,
+					     se_cmd, se_cmd->scsi_status);
+}
+
+static void tcm_loop_queue_tm_rsp(struct se_cmd *se_cmd)
+{
+	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
+				struct tcm_loop_cmd, tl_se_cmd);
+
+	/* Wake up tcm_loop_issue_tmr(). */
+	complete(&tl_cmd->tmr_done);
+}
+
+static void tcm_loop_aborted_task(struct se_cmd *se_cmd)
+{
+	return;
+}
+
+static char *tcm_loop_dump_proto_id(struct tcm_loop_hba *tl_hba)
+{
+	switch (tl_hba->tl_proto_id) {
+	case SCSI_PROTOCOL_SAS:
+		return "SAS";
+	case SCSI_PROTOCOL_FCP:
+		return "FCP";
+	case SCSI_PROTOCOL_ISCSI:
+		return "iSCSI";
+	default:
+		break;
+	}
+
+	return "Unknown";
+}
+
+/* Start items for tcm_loop_port_cit */
+
+static int tcm_loop_port_link(
+	struct se_portal_group *se_tpg,
+	struct se_lun *lun)
+{
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+				struct tcm_loop_tpg, tl_se_tpg);
+	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
+
+	atomic_inc_mb(&tl_tpg->tl_tpg_port_count);
+	/*
+	 * Add Linux/SCSI struct scsi_device by HCTL
+	 */
+	scsi_add_device(tl_hba->sh, 0, tl_tpg->tl_tpgt, lun->unpacked_lun);
+
+	pr_debug("TCM_Loop_ConfigFS: Port Link Successful\n");
+	return 0;
+}
+
+static void tcm_loop_port_unlink(
+	struct se_portal_group *se_tpg,
+	struct se_lun *se_lun)
+{
+	struct scsi_device *sd;
+	struct tcm_loop_hba *tl_hba;
+	struct tcm_loop_tpg *tl_tpg;
+
+	tl_tpg = container_of(se_tpg, struct tcm_loop_tpg, tl_se_tpg);
+	tl_hba = tl_tpg->tl_hba;
+
+	sd = scsi_device_lookup(tl_hba->sh, 0, tl_tpg->tl_tpgt,
+				se_lun->unpacked_lun);
+	if (!sd) {
+		pr_err("Unable to locate struct scsi_device for %d:%d:%llu\n",
+		       0, tl_tpg->tl_tpgt, se_lun->unpacked_lun);
+		return;
+	}
+	/*
+	 * Remove Linux/SCSI struct scsi_device by HCTL
+	 */
+	scsi_remove_device(sd);
+	scsi_device_put(sd);
+
+	atomic_dec_mb(&tl_tpg->tl_tpg_port_count);
+
+	pr_debug("TCM_Loop_ConfigFS: Port Unlink Successful\n");
+}
+
+/* End items for tcm_loop_port_cit */
+
+static ssize_t tcm_loop_tpg_attrib_fabric_prot_type_show(
+		struct config_item *item, char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg, struct tcm_loop_tpg,
+						   tl_se_tpg);
+
+	return sprintf(page, "%d\n", tl_tpg->tl_fabric_prot_type);
+}
+
+static ssize_t tcm_loop_tpg_attrib_fabric_prot_type_store(
+		struct config_item *item, const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg, struct tcm_loop_tpg,
+						   tl_se_tpg);
+	unsigned long val;
+	int ret = kstrtoul(page, 0, &val);
+
+	if (ret) {
+		pr_err("kstrtoul() returned %d for fabric_prot_type\n", ret);
+		return ret;
+	}
+	if (val != 0 && val != 1 && val != 3) {
+		pr_err("Invalid qla2xxx fabric_prot_type: %lu\n", val);
+		return -EINVAL;
+	}
+	tl_tpg->tl_fabric_prot_type = val;
+
+	return count;
+}
+
+CONFIGFS_ATTR(tcm_loop_tpg_attrib_, fabric_prot_type);
+
+static struct configfs_attribute *tcm_loop_tpg_attrib_attrs[] = {
+	&tcm_loop_tpg_attrib_attr_fabric_prot_type,
+	NULL,
+};
+
+/* Start items for tcm_loop_nexus_cit */
+
+static int tcm_loop_alloc_sess_cb(struct se_portal_group *se_tpg,
+				  struct se_session *se_sess, void *p)
+{
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+					struct tcm_loop_tpg, tl_se_tpg);
+
+	tl_tpg->tl_nexus = p;
+	return 0;
+}
+
+static int tcm_loop_make_nexus(
+	struct tcm_loop_tpg *tl_tpg,
+	const char *name)
+{
+	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
+	struct tcm_loop_nexus *tl_nexus;
+	int ret;
+
+	if (tl_tpg->tl_nexus) {
+		pr_debug("tl_tpg->tl_nexus already exists\n");
+		return -EEXIST;
+	}
+
+	tl_nexus = kzalloc_obj(*tl_nexus);
+	if (!tl_nexus)
+		return -ENOMEM;
+
+	tl_nexus->se_sess = target_setup_session(&tl_tpg->tl_se_tpg, 0, 0,
+					TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS,
+					name, tl_nexus, tcm_loop_alloc_sess_cb);
+	if (IS_ERR(tl_nexus->se_sess)) {
+		ret = PTR_ERR(tl_nexus->se_sess);
+		kfree(tl_nexus);
+		return ret;
+	}
+
+	pr_debug("TCM_Loop_ConfigFS: Established I_T Nexus to emulated %s Initiator Port: %s\n",
+		 tcm_loop_dump_proto_id(tl_hba), name);
+	return 0;
+}
+
+static int tcm_loop_drop_nexus(
+	struct tcm_loop_tpg *tpg)
+{
+	struct se_session *se_sess;
+	struct tcm_loop_nexus *tl_nexus;
+
+	tl_nexus = tpg->tl_nexus;
+	if (!tl_nexus)
+		return -ENODEV;
+
+	se_sess = tl_nexus->se_sess;
+	if (!se_sess)
+		return -ENODEV;
+
+	if (atomic_read(&tpg->tl_tpg_port_count)) {
+		pr_err("Unable to remove TCM_Loop I_T Nexus with active TPG port count: %d\n",
+		       atomic_read(&tpg->tl_tpg_port_count));
+		return -EPERM;
+	}
+
+	pr_debug("TCM_Loop_ConfigFS: Removing I_T Nexus to emulated %s Initiator Port: %s\n",
+		 tcm_loop_dump_proto_id(tpg->tl_hba),
+		 tl_nexus->se_sess->se_node_acl->initiatorname);
+	/*
+	 * Release the SCSI I_T Nexus to the emulated Target Port
+	 */
+	target_remove_session(se_sess);
+	tpg->tl_nexus = NULL;
+	kfree(tl_nexus);
+	return 0;
+}
+
+/* End items for tcm_loop_nexus_cit */
+
+static ssize_t tcm_loop_tpg_nexus_show(struct config_item *item, char *page)
+{
+	struct se_portal_group *se_tpg = to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+			struct tcm_loop_tpg, tl_se_tpg);
+	struct tcm_loop_nexus *tl_nexus;
+	ssize_t ret;
+
+	tl_nexus = tl_tpg->tl_nexus;
+	if (!tl_nexus)
+		return -ENODEV;
+
+	ret = snprintf(page, PAGE_SIZE, "%s\n",
+		tl_nexus->se_sess->se_node_acl->initiatorname);
+
+	return ret;
+}
+
+static ssize_t tcm_loop_tpg_nexus_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+			struct tcm_loop_tpg, tl_se_tpg);
+	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
+	unsigned char i_port[TL_WWN_ADDR_LEN], *ptr, *port_ptr;
+	int ret;
+	/*
+	 * Shutdown the active I_T nexus if 'NULL' is passed..
+	 */
+	if (!strncmp(page, "NULL", 4)) {
+		ret = tcm_loop_drop_nexus(tl_tpg);
+		return (!ret) ? count : ret;
+	}
+	/*
+	 * Otherwise make sure the passed virtual Initiator port WWN matches
+	 * the fabric protocol_id set in tcm_loop_make_scsi_hba(), and call
+	 * tcm_loop_make_nexus()
+	 */
+	if (strlen(page) >= TL_WWN_ADDR_LEN) {
+		pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
+		       page, TL_WWN_ADDR_LEN);
+		return -EINVAL;
+	}
+	snprintf(&i_port[0], TL_WWN_ADDR_LEN, "%s", page);
+
+	ptr = strstr(i_port, "naa.");
+	if (ptr) {
+		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_SAS) {
+			pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
+			       i_port, tcm_loop_dump_proto_id(tl_hba));
+			return -EINVAL;
+		}
+		port_ptr = &i_port[0];
+		goto check_newline;
+	}
+	ptr = strstr(i_port, "fc.");
+	if (ptr) {
+		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_FCP) {
+			pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
+			       i_port, tcm_loop_dump_proto_id(tl_hba));
+			return -EINVAL;
+		}
+		port_ptr = &i_port[3]; /* Skip over "fc." */
+		goto check_newline;
+	}
+	ptr = strstr(i_port, "iqn.");
+	if (ptr) {
+		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_ISCSI) {
+			pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
+			       i_port, tcm_loop_dump_proto_id(tl_hba));
+			return -EINVAL;
+		}
+		port_ptr = &i_port[0];
+		goto check_newline;
+	}
+	pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
+	       i_port);
+	return -EINVAL;
+	/*
+	 * Clear any trailing newline for the NAA WWN
+	 */
+check_newline:
+	if (i_port[strlen(i_port)-1] == '\n')
+		i_port[strlen(i_port)-1] = '\0';
+
+	ret = tcm_loop_make_nexus(tl_tpg, port_ptr);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t tcm_loop_tpg_transport_status_show(struct config_item *item,
+		char *page)
+{
+	struct se_portal_group *se_tpg = to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+			struct tcm_loop_tpg, tl_se_tpg);
+	const char *status = NULL;
+	ssize_t ret = -EINVAL;
+
+	switch (tl_tpg->tl_transport_status) {
+	case TCM_TRANSPORT_ONLINE:
+		status = "online";
+		break;
+	case TCM_TRANSPORT_OFFLINE:
+		status = "offline";
+		break;
+	default:
+		break;
+	}
+
+	if (status)
+		ret = snprintf(page, PAGE_SIZE, "%s\n", status);
+
+	return ret;
+}
+
+static ssize_t tcm_loop_tpg_transport_status_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+			struct tcm_loop_tpg, tl_se_tpg);
+
+	if (!strncmp(page, "online", 6)) {
+		tl_tpg->tl_transport_status = TCM_TRANSPORT_ONLINE;
+		return count;
+	}
+	if (!strncmp(page, "offline", 7)) {
+		tl_tpg->tl_transport_status = TCM_TRANSPORT_OFFLINE;
+		if (tl_tpg->tl_nexus) {
+			struct se_session *tl_sess = tl_tpg->tl_nexus->se_sess;
+
+			core_allocate_nexus_loss_ua(tl_sess->se_node_acl);
+		}
+		return count;
+	}
+	return -EINVAL;
+}
+
+static ssize_t tcm_loop_tpg_address_show(struct config_item *item,
+					 char *page)
+{
+	struct se_portal_group *se_tpg = to_tpg(item);
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+			struct tcm_loop_tpg, tl_se_tpg);
+	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
+
+	if (!tl_hba->sh)
+		return -ENODEV;
+
+	return snprintf(page, PAGE_SIZE, "%d:0:%d\n",
+			tl_hba->sh->host_no, tl_tpg->tl_tpgt);
+}
+
+CONFIGFS_ATTR(tcm_loop_tpg_, nexus);
+CONFIGFS_ATTR(tcm_loop_tpg_, transport_status);
+CONFIGFS_ATTR_RO(tcm_loop_tpg_, address);
+
+static struct configfs_attribute *tcm_loop_tpg_attrs[] = {
+	&tcm_loop_tpg_attr_nexus,
+	&tcm_loop_tpg_attr_transport_status,
+	&tcm_loop_tpg_attr_address,
+	NULL,
+};
+
+/* Start items for tcm_loop_naa_cit */
+
+static struct se_portal_group *tcm_loop_make_naa_tpg(struct se_wwn *wwn,
+						     const char *name)
+{
+	struct tcm_loop_hba *tl_hba = container_of(wwn,
+			struct tcm_loop_hba, tl_hba_wwn);
+	struct tcm_loop_tpg *tl_tpg;
+	int ret;
+	unsigned long tpgt;
+
+	if (strstr(name, "tpgt_") != name) {
+		pr_err("Unable to locate \"tpgt_#\" directory group\n");
+		return ERR_PTR(-EINVAL);
+	}
+	if (kstrtoul(name+5, 10, &tpgt))
+		return ERR_PTR(-EINVAL);
+
+	if (tpgt >= TL_TPGS_PER_HBA) {
+		pr_err("Passed tpgt: %lu exceeds TL_TPGS_PER_HBA: %u\n",
+		       tpgt, TL_TPGS_PER_HBA);
+		return ERR_PTR(-EINVAL);
+	}
+	tl_tpg = &tl_hba->tl_hba_tpgs[tpgt];
+	tl_tpg->tl_hba = tl_hba;
+	tl_tpg->tl_tpgt = tpgt;
+	/*
+	 * Register the tl_tpg as a emulated TCM Target Endpoint
+	 */
+	ret = core_tpg_register(wwn, &tl_tpg->tl_se_tpg, tl_hba->tl_proto_id);
+	if (ret < 0)
+		return ERR_PTR(-ENOMEM);
+
+	pr_debug("TCM_Loop_ConfigFS: Allocated Emulated %s Target Port %s,t,0x%04lx\n",
+		 tcm_loop_dump_proto_id(tl_hba),
+		 config_item_name(&wwn->wwn_group.cg_item), tpgt);
+	return &tl_tpg->tl_se_tpg;
+}
+
+static void tcm_loop_drop_naa_tpg(
+	struct se_portal_group *se_tpg)
+{
+	struct se_wwn *wwn = se_tpg->se_tpg_wwn;
+	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
+				struct tcm_loop_tpg, tl_se_tpg);
+	struct tcm_loop_hba *tl_hba;
+	unsigned short tpgt;
+
+	tl_hba = tl_tpg->tl_hba;
+	tpgt = tl_tpg->tl_tpgt;
+	/*
+	 * Release the I_T Nexus for the Virtual target link if present
+	 */
+	tcm_loop_drop_nexus(tl_tpg);
+	/*
+	 * Deregister the tl_tpg as a emulated TCM Target Endpoint
+	 */
+	core_tpg_deregister(se_tpg);
+
+	tl_tpg->tl_hba = NULL;
+	tl_tpg->tl_tpgt = 0;
+
+	pr_debug("TCM_Loop_ConfigFS: Deallocated Emulated %s Target Port %s,t,0x%04x\n",
+		 tcm_loop_dump_proto_id(tl_hba),
+		 config_item_name(&wwn->wwn_group.cg_item), tpgt);
+}
+
+/* End items for tcm_loop_naa_cit */
+
+/* Start items for tcm_loop_cit */
+
+static struct se_wwn *tcm_loop_make_scsi_hba(
+	struct target_fabric_configfs *tf,
+	struct config_group *group,
+	const char *name)
+{
+	struct tcm_loop_hba *tl_hba;
+	struct Scsi_Host *sh;
+	char *ptr;
+	int ret, off = 0;
+
+	tl_hba = kzalloc_obj(*tl_hba);
+	if (!tl_hba)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Determine the emulated Protocol Identifier and Target Port Name
+	 * based on the incoming configfs directory name.
+	 */
+	ptr = strstr(name, "naa.");
+	if (ptr) {
+		tl_hba->tl_proto_id = SCSI_PROTOCOL_SAS;
+		goto check_len;
+	}
+	ptr = strstr(name, "fc.");
+	if (ptr) {
+		tl_hba->tl_proto_id = SCSI_PROTOCOL_FCP;
+		off = 3; /* Skip over "fc." */
+		goto check_len;
+	}
+	ptr = strstr(name, "iqn.");
+	if (!ptr) {
+		pr_err("Unable to locate prefix for emulated Target Port: %s\n",
+		       name);
+		ret = -EINVAL;
+		goto out;
+	}
+	tl_hba->tl_proto_id = SCSI_PROTOCOL_ISCSI;
+
+check_len:
+	if (strlen(name) >= TL_WWN_ADDR_LEN) {
+		pr_err("Emulated NAA %s Address: %s, exceeds max: %d\n",
+		       name, tcm_loop_dump_proto_id(tl_hba), TL_WWN_ADDR_LEN);
+		ret = -EINVAL;
+		goto out;
+	}
+	snprintf(&tl_hba->tl_wwn_address[0], TL_WWN_ADDR_LEN, "%s", &name[off]);
+
+	/*
+	 * Call device_register(tl_hba->dev) to register the emulated
+	 * Linux/SCSI LLD of type struct Scsi_Host at tl_hba->sh after
+	 * device_register() callbacks in tcm_loop_driver_probe()
+	 */
+	ret = tcm_loop_setup_hba_bus(tl_hba, tcm_loop_hba_no_cnt);
+	if (ret)
+		return ERR_PTR(ret);
+
+	sh = tl_hba->sh;
+	tcm_loop_hba_no_cnt++;
+	pr_debug("TCM_Loop_ConfigFS: Allocated emulated Target %s Address: %s at Linux/SCSI Host ID: %d\n",
+		 tcm_loop_dump_proto_id(tl_hba), name, sh->host_no);
+	return &tl_hba->tl_hba_wwn;
+out:
+	kfree(tl_hba);
+	return ERR_PTR(ret);
+}
+
+static void tcm_loop_drop_scsi_hba(
+	struct se_wwn *wwn)
+{
+	struct tcm_loop_hba *tl_hba = container_of(wwn,
+				struct tcm_loop_hba, tl_hba_wwn);
+
+	pr_debug("TCM_Loop_ConfigFS: Deallocating emulated Target %s Address: %s at Linux/SCSI Host ID: %d\n",
+		 tcm_loop_dump_proto_id(tl_hba), tl_hba->tl_wwn_address,
+		 tl_hba->sh->host_no);
+	/*
+	 * Call device_unregister() on the original tl_hba->dev.
+	 * tcm_loop_fabric_scsi.c:tcm_loop_release_adapter() will
+	 * release *tl_hba;
+	 */
+	device_unregister(&tl_hba->dev);
+}
+
+/* Start items for tcm_loop_cit */
+static ssize_t tcm_loop_wwn_version_show(struct config_item *item, char *page)
+{
+	return sprintf(page, "TCM Loopback Fabric module %s\n", TCM_LOOP_VERSION);
+}
+
+CONFIGFS_ATTR_RO(tcm_loop_wwn_, version);
+
+static struct configfs_attribute *tcm_loop_wwn_attrs[] = {
+	&tcm_loop_wwn_attr_version,
+	NULL,
+};
+
+/* End items for tcm_loop_cit */
+
+static const struct target_core_fabric_ops loop_ops = {
+	.module				= THIS_MODULE,
+	.fabric_name			= "loopback",
+	.tpg_get_wwn			= tcm_loop_get_endpoint_wwn,
+	.tpg_get_tag			= tcm_loop_get_tag,
+	.tpg_check_demo_mode		= tcm_loop_check_demo_mode,
+	.tpg_check_prot_fabric_only	= tcm_loop_check_prot_fabric_only,
+	.check_stop_free		= tcm_loop_check_stop_free,
+	.release_cmd			= tcm_loop_release_cmd,
+	.sess_get_index			= tcm_loop_sess_get_index,
+	.write_pending			= tcm_loop_write_pending,
+	.get_cmd_state			= tcm_loop_get_cmd_state,
+	.queue_data_in			= tcm_loop_queue_data_in,
+	.queue_status			= tcm_loop_queue_status,
+	.queue_tm_rsp			= tcm_loop_queue_tm_rsp,
+	.aborted_task			= tcm_loop_aborted_task,
+	.fabric_make_wwn		= tcm_loop_make_scsi_hba,
+	.fabric_drop_wwn		= tcm_loop_drop_scsi_hba,
+	.fabric_make_tpg		= tcm_loop_make_naa_tpg,
+	.fabric_drop_tpg		= tcm_loop_drop_naa_tpg,
+	.fabric_post_link		= tcm_loop_port_link,
+	.fabric_pre_unlink		= tcm_loop_port_unlink,
+	.tfc_wwn_attrs			= tcm_loop_wwn_attrs,
+	.tfc_tpg_base_attrs		= tcm_loop_tpg_attrs,
+	.tfc_tpg_attrib_attrs		= tcm_loop_tpg_attrib_attrs,
+	.default_compl_type		= TARGET_QUEUE_COMPL,
+	.default_submit_type		= TARGET_QUEUE_SUBMIT,
+	.direct_submit_supp		= 0,
+};
+
+static int __init tcm_loop_fabric_init(void)
+{
+	int ret = -ENOMEM;
+
+	tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
+				sizeof(struct tcm_loop_cmd),
+				__alignof__(struct tcm_loop_cmd),
+				0, NULL);
+	if (!tcm_loop_cmd_cache) {
+		pr_debug("kmem_cache_create() for tcm_loop_cmd_cache failed\n");
+		goto out;
+	}
+
+	ret = tcm_loop_alloc_core_bus();
+	if (ret)
+		goto out_destroy_cache;
+
+	ret = target_register_template(&loop_ops);
+	if (ret)
+		goto out_release_core_bus;
+
+	return 0;
+
+out_release_core_bus:
+	tcm_loop_release_core_bus();
+out_destroy_cache:
+	kmem_cache_destroy(tcm_loop_cmd_cache);
+out:
+	return ret;
+}
+
+static void __exit tcm_loop_fabric_exit(void)
+{
+	target_unregister_template(&loop_ops);
+	tcm_loop_release_core_bus();
+	kmem_cache_destroy(tcm_loop_cmd_cache);
+}
+
+MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");
+MODULE_AUTHOR("Nicholas A. Bellinger <nab@risingtidesystems.com>");
+MODULE_LICENSE("GPL");
+module_init(tcm_loop_fabric_init);
+module_exit(tcm_loop_fabric_exit);
diff --git a/drivers/target/loopback/tcm_loop.h b/drivers/target/loopback/tcm_loop.h
new file mode 100644
index 000000000..437663b39
--- /dev/null
+++ b/drivers/target/loopback/tcm_loop.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/types.h>
+#include <linux/device.h>
+#include <target/target_core_base.h> /* struct se_cmd */
+
+#define TCM_LOOP_VERSION		"v2.1-rc2"
+#define TL_WWN_ADDR_LEN			256
+#define TL_TPGS_PER_HBA			32
+
+struct tcm_loop_cmd {
+	/* State of Linux/SCSI CDB+Data descriptor */
+	u32 sc_cmd_state;
+	/* Tagged command queueing */
+	u32 sc_cmd_tag;
+	/* Pointer to the CDB+Data descriptor from Linux/SCSI subsystem */
+	struct scsi_cmnd *sc;
+	/* The TCM I/O descriptor that is accessed via container_of() */
+	struct se_cmd tl_se_cmd;
+	struct completion tmr_done;
+	/* Sense buffer that will be mapped into outgoing status */
+	unsigned char tl_sense_buf[TRANSPORT_SENSE_BUFFER];
+};
+
+struct tcm_loop_nexus {
+	/*
+	 * Pointer to TCM session for I_T Nexus
+	 */
+	struct se_session *se_sess;
+};
+
+#define TCM_TRANSPORT_ONLINE 0
+#define TCM_TRANSPORT_OFFLINE 1
+
+struct tcm_loop_tpg {
+	unsigned short tl_tpgt;
+	unsigned short tl_transport_status;
+	enum target_prot_type tl_fabric_prot_type;
+	atomic_t tl_tpg_port_count;
+	struct se_portal_group tl_se_tpg;
+	struct tcm_loop_hba *tl_hba;
+	struct tcm_loop_nexus *tl_nexus;
+};
+
+struct tcm_loop_hba {
+	u8 tl_proto_id;
+	unsigned char tl_wwn_address[TL_WWN_ADDR_LEN];
+	struct se_hba_s *se_hba;
+	struct se_lun *tl_hba_lun;
+	struct se_port *tl_hba_lun_sep;
+	struct device dev;
+	struct Scsi_Host *sh;
+	struct tcm_loop_tpg tl_hba_tpgs[TL_TPGS_PER_HBA];
+	struct se_wwn tl_hba_wwn;
+};