Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 711 insertions, 0 deletions

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
new file mode 100644
index 000000000..c0e429e5e
--- /dev/null
+++ b/drivers/target/target_core_tpg.c
@@ -0,0 +1,711 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*******************************************************************************
+ * Filename:  target_core_tpg.c
+ *
+ * This file contains generic Target Portal Group related functions.
+ *
+ * (c) Copyright 2002-2013 Datera, Inc.
+ *
+ * Nicholas A. Bellinger <nab@kernel.org>
+ *
+ ******************************************************************************/
+
+#include <linux/net.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/in.h>
+#include <linux/export.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <scsi/scsi_proto.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_backend.h>
+#include <target/target_core_fabric.h>
+
+#include "target_core_internal.h"
+#include "target_core_alua.h"
+#include "target_core_pr.h"
+#include "target_core_ua.h"
+
+extern struct se_device *g_lun0_dev;
+static DEFINE_XARRAY_ALLOC(tpg_xa);
+
+/*	__core_tpg_get_initiator_node_acl():
+ *
+ *	mutex_lock(&tpg->acl_node_mutex); must be held when calling
+ */
+struct se_node_acl *__core_tpg_get_initiator_node_acl(
+	struct se_portal_group *tpg,
+	const char *initiatorname)
+{
+	struct se_node_acl *acl;
+
+	list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
+		if (!strcmp(acl->initiatorname, initiatorname))
+			return acl;
+	}
+
+	return NULL;
+}
+
+/*	core_tpg_get_initiator_node_acl():
+ *
+ *
+ */
+struct se_node_acl *core_tpg_get_initiator_node_acl(
+	struct se_portal_group *tpg,
+	unsigned char *initiatorname)
+{
+	struct se_node_acl *acl;
+	/*
+	 * Obtain se_node_acl->acl_kref using fabric driver provided
+	 * initiatorname[] during node acl endpoint lookup driven by
+	 * new se_session login.
+	 *
+	 * The reference is held until se_session shutdown -> release
+	 * occurs via fabric driver invoked transport_deregister_session()
+	 * or transport_free_session() code.
+	 */
+	mutex_lock(&tpg->acl_node_mutex);
+	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
+	if (acl) {
+		if (!kref_get_unless_zero(&acl->acl_kref))
+			acl = NULL;
+	}
+	mutex_unlock(&tpg->acl_node_mutex);
+
+	return acl;
+}
+EXPORT_SYMBOL(core_tpg_get_initiator_node_acl);
+
+void core_allocate_nexus_loss_ua(
+	struct se_node_acl *nacl)
+{
+	struct se_dev_entry *deve;
+
+	if (!nacl)
+		return;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
+		core_scsi3_ua_allocate(deve, 0x29,
+			ASCQ_29H_NEXUS_LOSS_OCCURRED);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(core_allocate_nexus_loss_ua);
+
+/*	core_tpg_add_node_to_devs():
+ *
+ *
+ */
+void core_tpg_add_node_to_devs(
+	struct se_node_acl *acl,
+	struct se_portal_group *tpg,
+	struct se_lun *lun_orig)
+{
+	bool lun_access_ro = true;
+	struct se_lun *lun;
+	struct se_device *dev;
+
+	mutex_lock(&tpg->tpg_lun_mutex);
+	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
+		if (lun_orig && lun != lun_orig)
+			continue;
+
+		dev = rcu_dereference_check(lun->lun_se_dev,
+					    lockdep_is_held(&tpg->tpg_lun_mutex));
+		/*
+		 * By default in LIO-Target $FABRIC_MOD,
+		 * demo_mode_write_protect is ON, or READ_ONLY;
+		 */
+		if (!tpg->se_tpg_tfo->tpg_check_demo_mode_write_protect(tpg)) {
+			lun_access_ro = false;
+		} else {
+			/*
+			 * Allow only optical drives to issue R/W in default RO
+			 * demo mode.
+			 */
+			if (dev->transport->get_device_type(dev) == TYPE_DISK)
+				lun_access_ro = true;
+			else
+				lun_access_ro = false;
+		}
+
+		pr_debug("TARGET_CORE[%s]->TPG[%u]_LUN[%llu] - Adding %s"
+			" access for LUN in Demo Mode\n",
+			tpg->se_tpg_tfo->fabric_name,
+			tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
+			lun_access_ro ? "READ-ONLY" : "READ-WRITE");
+
+		core_enable_device_list_for_node(lun, NULL, lun->unpacked_lun,
+						 lun_access_ro, acl, tpg);
+		/*
+		 * Check to see if there are any existing persistent reservation
+		 * APTPL pre-registrations that need to be enabled for this dynamic
+		 * LUN ACL now..
+		 */
+		core_scsi3_check_aptpl_registration(dev, tpg, lun, acl,
+						    lun->unpacked_lun);
+	}
+	mutex_unlock(&tpg->tpg_lun_mutex);
+}
+
+static void
+target_set_nacl_queue_depth(struct se_portal_group *tpg,
+			    struct se_node_acl *acl, u32 queue_depth)
+{
+	acl->queue_depth = queue_depth;
+
+	if (!acl->queue_depth) {
+		pr_warn("Queue depth for %s Initiator Node: %s is 0,"
+			"defaulting to 1.\n", tpg->se_tpg_tfo->fabric_name,
+			acl->initiatorname);
+		acl->queue_depth = 1;
+	}
+}
+
+static struct se_node_acl *target_alloc_node_acl(struct se_portal_group *tpg,
+		const unsigned char *initiatorname)
+{
+	struct se_node_acl *acl;
+	u32 queue_depth;
+
+	acl = kzalloc(max(sizeof(*acl), tpg->se_tpg_tfo->node_acl_size),
+			GFP_KERNEL);
+	if (!acl)
+		return NULL;
+
+	INIT_LIST_HEAD(&acl->acl_list);
+	INIT_LIST_HEAD(&acl->acl_sess_list);
+	INIT_HLIST_HEAD(&acl->lun_entry_hlist);
+	kref_init(&acl->acl_kref);
+	init_completion(&acl->acl_free_comp);
+	spin_lock_init(&acl->nacl_sess_lock);
+	mutex_init(&acl->lun_entry_mutex);
+	atomic_set(&acl->acl_pr_ref_count, 0);
+
+	if (tpg->se_tpg_tfo->tpg_get_default_depth)
+		queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg);
+	else
+		queue_depth = 1;
+	target_set_nacl_queue_depth(tpg, acl, queue_depth);
+
+	snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname);
+	acl->se_tpg = tpg;
+	acl->acl_index = scsi_get_new_index(SCSI_AUTH_INTR_INDEX);
+
+	tpg->se_tpg_tfo->set_default_node_attributes(acl);
+
+	return acl;
+}
+
+static void target_add_node_acl(struct se_node_acl *acl)
+{
+	struct se_portal_group *tpg = acl->se_tpg;
+
+	mutex_lock(&tpg->acl_node_mutex);
+	list_add_tail(&acl->acl_list, &tpg->acl_node_list);
+	mutex_unlock(&tpg->acl_node_mutex);
+
+	pr_debug("%s_TPG[%hu] - Added %s ACL with TCQ Depth: %d for %s"
+		" Initiator Node: %s\n",
+		tpg->se_tpg_tfo->fabric_name,
+		tpg->se_tpg_tfo->tpg_get_tag(tpg),
+		acl->dynamic_node_acl ? "DYNAMIC" : "",
+		acl->queue_depth,
+		tpg->se_tpg_tfo->fabric_name,
+		acl->initiatorname);
+}
+
+bool target_tpg_has_node_acl(struct se_portal_group *tpg,
+			     const char *initiatorname)
+{
+	struct se_node_acl *acl;
+	bool found = false;
+
+	mutex_lock(&tpg->acl_node_mutex);
+	list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
+		if (!strcmp(acl->initiatorname, initiatorname)) {
+			found = true;
+			break;
+		}
+	}
+	mutex_unlock(&tpg->acl_node_mutex);
+
+	return found;
+}
+EXPORT_SYMBOL(target_tpg_has_node_acl);
+
+struct se_node_acl *core_tpg_check_initiator_node_acl(
+	struct se_portal_group *tpg,
+	unsigned char *initiatorname)
+{
+	struct se_node_acl *acl;
+
+	acl = core_tpg_get_initiator_node_acl(tpg, initiatorname);
+	if (acl)
+		return acl;
+
+	if (!tpg->se_tpg_tfo->tpg_check_demo_mode(tpg))
+		return NULL;
+
+	acl = target_alloc_node_acl(tpg, initiatorname);
+	if (!acl)
+		return NULL;
+	/*
+	 * When allocating a dynamically generated node_acl, go ahead
+	 * and take the extra kref now before returning to the fabric
+	 * driver caller.
+	 *
+	 * Note this reference will be released at session shutdown
+	 * time within transport_free_session() code.
+	 */
+	kref_get(&acl->acl_kref);
+	acl->dynamic_node_acl = 1;
+
+	/*
+	 * Here we only create demo-mode MappedLUNs from the active
+	 * TPG LUNs if the fabric is not explicitly asking for
+	 * tpg_check_demo_mode_login_only() == 1.
+	 */
+	if ((tpg->se_tpg_tfo->tpg_check_demo_mode_login_only == NULL) ||
+	    (tpg->se_tpg_tfo->tpg_check_demo_mode_login_only(tpg) != 1))
+		core_tpg_add_node_to_devs(acl, tpg, NULL);
+
+	target_add_node_acl(acl);
+	return acl;
+}
+EXPORT_SYMBOL(core_tpg_check_initiator_node_acl);
+
+void core_tpg_wait_for_nacl_pr_ref(struct se_node_acl *nacl)
+{
+	while (atomic_read(&nacl->acl_pr_ref_count) != 0)
+		cpu_relax();
+}
+
+struct se_node_acl *core_tpg_add_initiator_node_acl(
+	struct se_portal_group *tpg,
+	const char *initiatorname)
+{
+	struct se_node_acl *acl;
+
+	mutex_lock(&tpg->acl_node_mutex);
+	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
+	if (acl) {
+		if (acl->dynamic_node_acl) {
+			acl->dynamic_node_acl = 0;
+			pr_debug("%s_TPG[%u] - Replacing dynamic ACL"
+				" for %s\n", tpg->se_tpg_tfo->fabric_name,
+				tpg->se_tpg_tfo->tpg_get_tag(tpg), initiatorname);
+			mutex_unlock(&tpg->acl_node_mutex);
+			return acl;
+		}
+
+		pr_err("ACL entry for %s Initiator"
+			" Node %s already exists for TPG %u, ignoring"
+			" request.\n",  tpg->se_tpg_tfo->fabric_name,
+			initiatorname, tpg->se_tpg_tfo->tpg_get_tag(tpg));
+		mutex_unlock(&tpg->acl_node_mutex);
+		return ERR_PTR(-EEXIST);
+	}
+	mutex_unlock(&tpg->acl_node_mutex);
+
+	acl = target_alloc_node_acl(tpg, initiatorname);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	target_add_node_acl(acl);
+	return acl;
+}
+
+static void target_shutdown_sessions(struct se_node_acl *acl)
+{
+	struct se_session *sess;
+	unsigned long flags;
+
+restart:
+	spin_lock_irqsave(&acl->nacl_sess_lock, flags);
+	list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
+		if (sess->cmd_cnt && atomic_read(&sess->cmd_cnt->stopped))
+			continue;
+
+		list_del_init(&sess->sess_acl_list);
+		spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
+
+		if (acl->se_tpg->se_tpg_tfo->close_session)
+			acl->se_tpg->se_tpg_tfo->close_session(sess);
+		goto restart;
+	}
+	spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
+}
+
+void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
+{
+	struct se_portal_group *tpg = acl->se_tpg;
+
+	mutex_lock(&tpg->acl_node_mutex);
+	if (acl->dynamic_node_acl)
+		acl->dynamic_node_acl = 0;
+	list_del_init(&acl->acl_list);
+	mutex_unlock(&tpg->acl_node_mutex);
+
+	target_shutdown_sessions(acl);
+
+	target_put_nacl(acl);
+	/*
+	 * Wait for last target_put_nacl() to complete in target_complete_nacl()
+	 * for active fabric session transport_deregister_session() callbacks.
+	 */
+	wait_for_completion(&acl->acl_free_comp);
+
+	core_tpg_wait_for_nacl_pr_ref(acl);
+	core_free_device_list_for_node(acl, tpg);
+
+	pr_debug("%s_TPG[%hu] - Deleted ACL with TCQ Depth: %d for %s"
+		" Initiator Node: %s\n", tpg->se_tpg_tfo->fabric_name,
+		tpg->se_tpg_tfo->tpg_get_tag(tpg), acl->queue_depth,
+		tpg->se_tpg_tfo->fabric_name, acl->initiatorname);
+
+	kfree(acl);
+}
+
+/*	core_tpg_set_initiator_node_queue_depth():
+ *
+ *
+ */
+int core_tpg_set_initiator_node_queue_depth(
+	struct se_node_acl *acl,
+	u32 queue_depth)
+{
+	struct se_portal_group *tpg = acl->se_tpg;
+
+	/*
+	 * Allow the setting of se_node_acl queue_depth to be idempotent,
+	 * and not force a session shutdown event if the value is not
+	 * changing.
+	 */
+	if (acl->queue_depth == queue_depth)
+		return 0;
+	/*
+	 * User has requested to change the queue depth for a Initiator Node.
+	 * Change the value in the Node's struct se_node_acl, and call
+	 * target_set_nacl_queue_depth() to set the new queue depth.
+	 */
+	target_set_nacl_queue_depth(tpg, acl, queue_depth);
+
+	/*
+	 * Shutdown all pending sessions to force session reinstatement.
+	 */
+	target_shutdown_sessions(acl);
+
+	pr_debug("Successfully changed queue depth to: %d for Initiator"
+		" Node: %s on %s Target Portal Group: %u\n", acl->queue_depth,
+		acl->initiatorname, tpg->se_tpg_tfo->fabric_name,
+		tpg->se_tpg_tfo->tpg_get_tag(tpg));
+
+	return 0;
+}
+EXPORT_SYMBOL(core_tpg_set_initiator_node_queue_depth);
+
+/*	core_tpg_set_initiator_node_tag():
+ *
+ *	Initiator nodeacl tags are not used internally, but may be used by
+ *	userspace to emulate aliases or groups.
+ *	Returns length of newly-set tag or -EINVAL.
+ */
+int core_tpg_set_initiator_node_tag(
+	struct se_portal_group *tpg,
+	struct se_node_acl *acl,
+	const char *new_tag)
+{
+	if (strlen(new_tag) >= MAX_ACL_TAG_SIZE)
+		return -EINVAL;
+
+	if (!strncmp("NULL", new_tag, 4)) {
+		acl->acl_tag[0] = '\0';
+		return 0;
+	}
+
+	return snprintf(acl->acl_tag, MAX_ACL_TAG_SIZE, "%s", new_tag);
+}
+EXPORT_SYMBOL(core_tpg_set_initiator_node_tag);
+
+static void core_tpg_lun_ref_release(struct percpu_ref *ref)
+{
+	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
+
+	complete(&lun->lun_shutdown_comp);
+}
+
+static int target_tpg_register_rtpi(struct se_portal_group *se_tpg)
+{
+	u32 val;
+	int ret;
+
+	if (se_tpg->rtpi_manual) {
+		ret = xa_insert(&tpg_xa, se_tpg->tpg_rtpi, se_tpg, GFP_KERNEL);
+		if (ret) {
+			pr_info("%s_TPG[%hu] - Can not set RTPI %#x, it is already busy",
+				se_tpg->se_tpg_tfo->fabric_name,
+				se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg),
+				se_tpg->tpg_rtpi);
+			return -EINVAL;
+		}
+	} else {
+		ret = xa_alloc(&tpg_xa, &val, se_tpg,
+			       XA_LIMIT(1, USHRT_MAX), GFP_KERNEL);
+		if (!ret)
+			se_tpg->tpg_rtpi = val;
+	}
+
+	return ret;
+}
+
+static void target_tpg_deregister_rtpi(struct se_portal_group *se_tpg)
+{
+	if (se_tpg->tpg_rtpi && se_tpg->enabled)
+		xa_erase(&tpg_xa, se_tpg->tpg_rtpi);
+}
+
+int target_tpg_enable(struct se_portal_group *se_tpg)
+{
+	int ret;
+
+	ret = target_tpg_register_rtpi(se_tpg);
+	if (ret)
+		return ret;
+
+	ret = se_tpg->se_tpg_tfo->fabric_enable_tpg(se_tpg, true);
+	if (ret) {
+		target_tpg_deregister_rtpi(se_tpg);
+		return ret;
+	}
+
+	se_tpg->enabled = true;
+
+	return 0;
+}
+
+int target_tpg_disable(struct se_portal_group *se_tpg)
+{
+	int ret;
+
+	target_tpg_deregister_rtpi(se_tpg);
+
+	ret = se_tpg->se_tpg_tfo->fabric_enable_tpg(se_tpg, false);
+	if (!ret)
+		se_tpg->enabled = false;
+
+	return ret;
+}
+
+/* Does not change se_wwn->priv. */
+int core_tpg_register(
+	struct se_wwn *se_wwn,
+	struct se_portal_group *se_tpg,
+	int proto_id)
+{
+	int ret;
+
+	if (!se_tpg)
+		return -EINVAL;
+	/*
+	 * For the typical case where core_tpg_register() is called by a
+	 * fabric driver from target_core_fabric_ops->fabric_make_tpg()
+	 * configfs context, use the original tf_ops pointer already saved
+	 * by target-core in target_fabric_make_wwn().
+	 *
+	 * Otherwise, for special cases like iscsi-target discovery TPGs
+	 * the caller is responsible for setting ->se_tpg_tfo ahead of
+	 * calling core_tpg_register().
+	 */
+	if (se_wwn)
+		se_tpg->se_tpg_tfo = se_wwn->wwn_tf->tf_ops;
+
+	if (!se_tpg->se_tpg_tfo) {
+		pr_err("Unable to locate se_tpg->se_tpg_tfo pointer\n");
+		return -EINVAL;
+	}
+
+	INIT_HLIST_HEAD(&se_tpg->tpg_lun_hlist);
+	se_tpg->proto_id = proto_id;
+	se_tpg->se_tpg_wwn = se_wwn;
+	atomic_set(&se_tpg->tpg_pr_ref_count, 0);
+	INIT_LIST_HEAD(&se_tpg->acl_node_list);
+	INIT_LIST_HEAD(&se_tpg->tpg_sess_list);
+	spin_lock_init(&se_tpg->session_lock);
+	mutex_init(&se_tpg->tpg_lun_mutex);
+	mutex_init(&se_tpg->acl_node_mutex);
+
+	if (se_tpg->proto_id >= 0) {
+		se_tpg->tpg_virt_lun0 = core_tpg_alloc_lun(se_tpg, 0);
+		if (IS_ERR(se_tpg->tpg_virt_lun0))
+			return PTR_ERR(se_tpg->tpg_virt_lun0);
+
+		ret = core_tpg_add_lun(se_tpg, se_tpg->tpg_virt_lun0,
+				true, g_lun0_dev);
+		if (ret < 0) {
+			kfree(se_tpg->tpg_virt_lun0);
+			return ret;
+		}
+	}
+
+	pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
+		 "Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->fabric_name,
+		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) ?
+		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) : NULL,
+		se_tpg->proto_id, se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
+
+	return 0;
+}
+EXPORT_SYMBOL(core_tpg_register);
+
+int core_tpg_deregister(struct se_portal_group *se_tpg)
+{
+	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
+	struct se_node_acl *nacl, *nacl_tmp;
+	LIST_HEAD(node_list);
+
+	pr_debug("TARGET_CORE[%s]: Deallocating portal_group for endpoint: %s, "
+		 "Proto: %d, Portal Tag: %u\n", tfo->fabric_name,
+		tfo->tpg_get_wwn(se_tpg) ? tfo->tpg_get_wwn(se_tpg) : NULL,
+		se_tpg->proto_id, tfo->tpg_get_tag(se_tpg));
+
+	while (atomic_read(&se_tpg->tpg_pr_ref_count) != 0)
+		cpu_relax();
+
+	mutex_lock(&se_tpg->acl_node_mutex);
+	list_splice_init(&se_tpg->acl_node_list, &node_list);
+	mutex_unlock(&se_tpg->acl_node_mutex);
+	/*
+	 * Release any remaining demo-mode generated se_node_acl that have
+	 * not been released because of TFO->tpg_check_demo_mode_cache() == 1
+	 * in transport_deregister_session().
+	 */
+	list_for_each_entry_safe(nacl, nacl_tmp, &node_list, acl_list) {
+		list_del_init(&nacl->acl_list);
+
+		core_tpg_wait_for_nacl_pr_ref(nacl);
+		core_free_device_list_for_node(nacl, se_tpg);
+		kfree(nacl);
+	}
+
+	if (se_tpg->proto_id >= 0) {
+		core_tpg_remove_lun(se_tpg, se_tpg->tpg_virt_lun0);
+		kfree_rcu(se_tpg->tpg_virt_lun0, rcu_head);
+	}
+
+	target_tpg_deregister_rtpi(se_tpg);
+
+	return 0;
+}
+EXPORT_SYMBOL(core_tpg_deregister);
+
+struct se_lun *core_tpg_alloc_lun(
+	struct se_portal_group *tpg,
+	u64 unpacked_lun)
+{
+	struct se_lun *lun;
+
+	lun = kzalloc(sizeof(*lun), GFP_KERNEL);
+	if (!lun) {
+		pr_err("Unable to allocate se_lun memory\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	lun->unpacked_lun = unpacked_lun;
+	atomic_set(&lun->lun_acl_count, 0);
+	init_completion(&lun->lun_shutdown_comp);
+	INIT_LIST_HEAD(&lun->lun_deve_list);
+	INIT_LIST_HEAD(&lun->lun_dev_link);
+	atomic_set(&lun->lun_tg_pt_secondary_offline, 0);
+	spin_lock_init(&lun->lun_deve_lock);
+	mutex_init(&lun->lun_tg_pt_md_mutex);
+	INIT_LIST_HEAD(&lun->lun_tg_pt_gp_link);
+	spin_lock_init(&lun->lun_tg_pt_gp_lock);
+	lun->lun_tpg = tpg;
+
+	return lun;
+}
+
+int core_tpg_add_lun(
+	struct se_portal_group *tpg,
+	struct se_lun *lun,
+	bool lun_access_ro,
+	struct se_device *dev)
+{
+	int ret;
+
+	ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release, 0,
+			      GFP_KERNEL);
+	if (ret < 0)
+		goto out;
+
+	if (!(dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_ALUA) &&
+	    !(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
+		target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp);
+
+	mutex_lock(&tpg->tpg_lun_mutex);
+
+	spin_lock(&dev->se_port_lock);
+	lun->lun_index = dev->dev_index;
+	rcu_assign_pointer(lun->lun_se_dev, dev);
+	dev->export_count++;
+	list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
+	spin_unlock(&dev->se_port_lock);
+
+	if (dev->dev_flags & DF_READ_ONLY)
+		lun->lun_access_ro = true;
+	else
+		lun->lun_access_ro = lun_access_ro;
+	if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
+		hlist_add_head_rcu(&lun->link, &tpg->tpg_lun_hlist);
+	mutex_unlock(&tpg->tpg_lun_mutex);
+
+	return 0;
+
+out:
+	return ret;
+}
+
+void core_tpg_remove_lun(
+	struct se_portal_group *tpg,
+	struct se_lun *lun)
+{
+	/*
+	 * rcu_dereference_raw protected by se_lun->lun_group symlink
+	 * reference to se_device->dev_group.
+	 */
+	struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);
+
+	lun->lun_shutdown = true;
+
+	core_clear_lun_from_tpg(lun, tpg);
+	/*
+	 * Wait for any active I/O references to percpu se_lun->lun_ref to
+	 * be released.  Also, se_lun->lun_ref is now used by PR and ALUA
+	 * logic when referencing a remote target port during ALL_TGT_PT=1
+	 * and generating UNIT_ATTENTIONs for ALUA access state transition.
+	 */
+	transport_clear_lun_ref(lun);
+
+	mutex_lock(&tpg->tpg_lun_mutex);
+	if (lun->lun_se_dev) {
+		target_detach_tg_pt_gp(lun);
+
+		spin_lock(&dev->se_port_lock);
+		list_del(&lun->lun_dev_link);
+		dev->export_count--;
+		rcu_assign_pointer(lun->lun_se_dev, NULL);
+		spin_unlock(&dev->se_port_lock);
+	}
+	if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
+		hlist_del_rcu(&lun->link);
+
+	lun->lun_shutdown = false;
+	mutex_unlock(&tpg->tpg_lun_mutex);
+
+	percpu_ref_exit(&lun->lun_ref);
+}