WSL2-Linux-Kernel/drivers/target/target_core_tpg.c

722 строки
19 KiB
C

/*******************************************************************************
* 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>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
******************************************************************************/
#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_SPINLOCK(tpg_lock);
static LIST_HEAD(tpg_list);
/* __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;
mutex_lock(&tpg->acl_node_mutex);
acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
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)
{
u32 lun_access = 0;
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 = TRANSPORT_LUNFLAGS_READ_WRITE;
} 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 = TRANSPORT_LUNFLAGS_READ_ONLY;
else
lun_access = TRANSPORT_LUNFLAGS_READ_WRITE;
}
pr_debug("TARGET_CORE[%s]->TPG[%u]_LUN[%llu] - Adding %s"
" access for LUN in Demo Mode\n",
tpg->se_tpg_tfo->get_fabric_name(),
tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
(lun_access == TRANSPORT_LUNFLAGS_READ_WRITE) ?
"READ-WRITE" : "READ-ONLY");
core_enable_device_list_for_node(lun, NULL, lun->unpacked_lun,
lun_access, 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);
}
/* core_set_queue_depth_for_node():
*
*
*/
static int core_set_queue_depth_for_node(
struct se_portal_group *tpg,
struct se_node_acl *acl)
{
if (!acl->queue_depth) {
pr_err("Queue depth for %s Initiator Node: %s is 0,"
"defaulting to 1.\n", tpg->se_tpg_tfo->get_fabric_name(),
acl->initiatorname);
acl->queue_depth = 1;
}
return 0;
}
static struct se_node_acl *target_alloc_node_acl(struct se_portal_group *tpg,
const unsigned char *initiatorname)
{
struct se_node_acl *acl;
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)
acl->queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg);
else
acl->queue_depth = 1;
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);
if (core_set_queue_depth_for_node(tpg, acl) < 0)
goto out_free_acl;
return acl;
out_free_acl:
kfree(acl);
return NULL;
}
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);
tpg->num_node_acls++;
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->get_fabric_name(),
tpg->se_tpg_tfo->tpg_get_tag(tpg),
acl->dynamic_node_acl ? "DYNAMIC" : "",
acl->queue_depth,
tpg->se_tpg_tfo->get_fabric_name(),
acl->initiatorname);
}
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;
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->get_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->get_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;
}
void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
{
struct se_portal_group *tpg = acl->se_tpg;
LIST_HEAD(sess_list);
struct se_session *sess, *sess_tmp;
unsigned long flags;
int rc;
mutex_lock(&tpg->acl_node_mutex);
if (acl->dynamic_node_acl) {
acl->dynamic_node_acl = 0;
}
list_del(&acl->acl_list);
tpg->num_node_acls--;
mutex_unlock(&tpg->acl_node_mutex);
spin_lock_irqsave(&acl->nacl_sess_lock, flags);
acl->acl_stop = 1;
list_for_each_entry_safe(sess, sess_tmp, &acl->acl_sess_list,
sess_acl_list) {
if (sess->sess_tearing_down != 0)
continue;
target_get_session(sess);
list_move(&sess->sess_acl_list, &sess_list);
}
spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
list_for_each_entry_safe(sess, sess_tmp, &sess_list, sess_acl_list) {
list_del(&sess->sess_acl_list);
rc = tpg->se_tpg_tfo->shutdown_session(sess);
target_put_session(sess);
if (!rc)
continue;
target_put_session(sess);
}
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->get_fabric_name(),
tpg->se_tpg_tfo->tpg_get_tag(tpg), acl->queue_depth,
tpg->se_tpg_tfo->get_fabric_name(), acl->initiatorname);
kfree(acl);
}
/* core_tpg_set_initiator_node_queue_depth():
*
*
*/
int core_tpg_set_initiator_node_queue_depth(
struct se_portal_group *tpg,
unsigned char *initiatorname,
u32 queue_depth,
int force)
{
struct se_session *sess, *init_sess = NULL;
struct se_node_acl *acl;
unsigned long flags;
int dynamic_acl = 0;
mutex_lock(&tpg->acl_node_mutex);
acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
if (!acl) {
pr_err("Access Control List entry for %s Initiator"
" Node %s does not exists for TPG %hu, ignoring"
" request.\n", tpg->se_tpg_tfo->get_fabric_name(),
initiatorname, tpg->se_tpg_tfo->tpg_get_tag(tpg));
mutex_unlock(&tpg->acl_node_mutex);
return -ENODEV;
}
if (acl->dynamic_node_acl) {
acl->dynamic_node_acl = 0;
dynamic_acl = 1;
}
mutex_unlock(&tpg->acl_node_mutex);
spin_lock_irqsave(&tpg->session_lock, flags);
list_for_each_entry(sess, &tpg->tpg_sess_list, sess_list) {
if (sess->se_node_acl != acl)
continue;
if (!force) {
pr_err("Unable to change queue depth for %s"
" Initiator Node: %s while session is"
" operational. To forcefully change the queue"
" depth and force session reinstatement"
" use the \"force=1\" parameter.\n",
tpg->se_tpg_tfo->get_fabric_name(), initiatorname);
spin_unlock_irqrestore(&tpg->session_lock, flags);
mutex_lock(&tpg->acl_node_mutex);
if (dynamic_acl)
acl->dynamic_node_acl = 1;
mutex_unlock(&tpg->acl_node_mutex);
return -EEXIST;
}
/*
* Determine if the session needs to be closed by our context.
*/
if (!tpg->se_tpg_tfo->shutdown_session(sess))
continue;
init_sess = sess;
break;
}
/*
* 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
* core_set_queue_depth_for_node() to add the requested queue depth.
*
* Finally call tpg->se_tpg_tfo->close_session() to force session
* reinstatement to occur if there is an active session for the
* $FABRIC_MOD Initiator Node in question.
*/
acl->queue_depth = queue_depth;
if (core_set_queue_depth_for_node(tpg, acl) < 0) {
spin_unlock_irqrestore(&tpg->session_lock, flags);
/*
* Force session reinstatement if
* core_set_queue_depth_for_node() failed, because we assume
* the $FABRIC_MOD has already the set session reinstatement
* bit from tpg->se_tpg_tfo->shutdown_session() called above.
*/
if (init_sess)
tpg->se_tpg_tfo->close_session(init_sess);
mutex_lock(&tpg->acl_node_mutex);
if (dynamic_acl)
acl->dynamic_node_acl = 1;
mutex_unlock(&tpg->acl_node_mutex);
return -EINVAL;
}
spin_unlock_irqrestore(&tpg->session_lock, flags);
/*
* If the $FABRIC_MOD session for the Initiator Node ACL exists,
* forcefully shutdown the $FABRIC_MOD session/nexus.
*/
if (init_sess)
tpg->se_tpg_tfo->close_session(init_sess);
pr_debug("Successfully changed queue depth to: %d for Initiator"
" Node: %s on %s Target Portal Group: %u\n", queue_depth,
initiatorname, tpg->se_tpg_tfo->get_fabric_name(),
tpg->se_tpg_tfo->tpg_get_tag(tpg));
mutex_lock(&tpg->acl_node_mutex);
if (dynamic_acl)
acl->dynamic_node_acl = 1;
mutex_unlock(&tpg->acl_node_mutex);
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_ref_comp);
}
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->se_tpg_node);
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,
TRANSPORT_LUNFLAGS_READ_ONLY, g_lun0_dev);
if (ret < 0) {
kfree(se_tpg->tpg_virt_lun0);
return ret;
}
}
spin_lock_bh(&tpg_lock);
list_add_tail(&se_tpg->se_tpg_node, &tpg_list);
spin_unlock_bh(&tpg_lock);
pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
"Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->get_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->get_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));
spin_lock_bh(&tpg_lock);
list_del(&se_tpg->se_tpg_node);
spin_unlock_bh(&tpg_lock);
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(&nacl->acl_list);
se_tpg->num_node_acls--;
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);
}
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;
lun->lun_link_magic = SE_LUN_LINK_MAGIC;
atomic_set(&lun->lun_acl_count, 0);
init_completion(&lun->lun_ref_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,
u32 lun_access,
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;
ret = core_alloc_rtpi(lun, dev);
if (ret)
goto out_kill_ref;
if (!(dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH) &&
!(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 = TRANSPORT_LUNFLAGS_READ_ONLY;
else
lun->lun_access = lun_access;
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_kill_ref:
percpu_ref_exit(&lun->lun_ref);
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);
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);
mutex_unlock(&tpg->tpg_lun_mutex);
percpu_ref_exit(&lun->lun_ref);
}