1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3  * Filename:  target_core_tpg.c
4  *
5  * This file contains generic Target Portal Group related functions.
6  *
7  * (c) Copyright 2002-2013 Datera, Inc.
8  *
9  * Nicholas A. Bellinger <nab@kernel.org>
10  *
11  ******************************************************************************/
12 
13 #include <linux/net.h>
14 #include <linux/string.h>
15 #include <linux/timer.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 #include <linux/in.h>
19 #include <linux/export.h>
20 #include <net/sock.h>
21 #include <net/tcp.h>
22 #include <scsi/scsi_proto.h>
23 
24 #include <target/target_core_base.h>
25 #include <target/target_core_backend.h>
26 #include <target/target_core_fabric.h>
27 
28 #include "target_core_internal.h"
29 #include "target_core_alua.h"
30 #include "target_core_pr.h"
31 #include "target_core_ua.h"
32 
33 extern struct se_device *g_lun0_dev;
34 
35 /*	__core_tpg_get_initiator_node_acl():
36  *
37  *	mutex_lock(&tpg->acl_node_mutex); must be held when calling
38  */
39 struct se_node_acl *__core_tpg_get_initiator_node_acl(
40 	struct se_portal_group *tpg,
41 	const char *initiatorname)
42 {
43 	struct se_node_acl *acl;
44 
45 	list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
46 		if (!strcmp(acl->initiatorname, initiatorname))
47 			return acl;
48 	}
49 
50 	return NULL;
51 }
52 
53 /*	core_tpg_get_initiator_node_acl():
54  *
55  *
56  */
57 struct se_node_acl *core_tpg_get_initiator_node_acl(
58 	struct se_portal_group *tpg,
59 	unsigned char *initiatorname)
60 {
61 	struct se_node_acl *acl;
62 	/*
63 	 * Obtain se_node_acl->acl_kref using fabric driver provided
64 	 * initiatorname[] during node acl endpoint lookup driven by
65 	 * new se_session login.
66 	 *
67 	 * The reference is held until se_session shutdown -> release
68 	 * occurs via fabric driver invoked transport_deregister_session()
69 	 * or transport_free_session() code.
70 	 */
71 	mutex_lock(&tpg->acl_node_mutex);
72 	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
73 	if (acl) {
74 		if (!kref_get_unless_zero(&acl->acl_kref))
75 			acl = NULL;
76 	}
77 	mutex_unlock(&tpg->acl_node_mutex);
78 
79 	return acl;
80 }
81 EXPORT_SYMBOL(core_tpg_get_initiator_node_acl);
82 
83 void core_allocate_nexus_loss_ua(
84 	struct se_node_acl *nacl)
85 {
86 	struct se_dev_entry *deve;
87 
88 	if (!nacl)
89 		return;
90 
91 	rcu_read_lock();
92 	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
93 		core_scsi3_ua_allocate(deve, 0x29,
94 			ASCQ_29H_NEXUS_LOSS_OCCURRED);
95 	rcu_read_unlock();
96 }
97 EXPORT_SYMBOL(core_allocate_nexus_loss_ua);
98 
99 /*	core_tpg_add_node_to_devs():
100  *
101  *
102  */
103 void core_tpg_add_node_to_devs(
104 	struct se_node_acl *acl,
105 	struct se_portal_group *tpg,
106 	struct se_lun *lun_orig)
107 {
108 	bool lun_access_ro = true;
109 	struct se_lun *lun;
110 	struct se_device *dev;
111 
112 	mutex_lock(&tpg->tpg_lun_mutex);
113 	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
114 		if (lun_orig && lun != lun_orig)
115 			continue;
116 
117 		dev = rcu_dereference_check(lun->lun_se_dev,
118 					    lockdep_is_held(&tpg->tpg_lun_mutex));
119 		/*
120 		 * By default in LIO-Target $FABRIC_MOD,
121 		 * demo_mode_write_protect is ON, or READ_ONLY;
122 		 */
123 		if (!tpg->se_tpg_tfo->tpg_check_demo_mode_write_protect(tpg)) {
124 			lun_access_ro = false;
125 		} else {
126 			/*
127 			 * Allow only optical drives to issue R/W in default RO
128 			 * demo mode.
129 			 */
130 			if (dev->transport->get_device_type(dev) == TYPE_DISK)
131 				lun_access_ro = true;
132 			else
133 				lun_access_ro = false;
134 		}
135 
136 		pr_debug("TARGET_CORE[%s]->TPG[%u]_LUN[%llu] - Adding %s"
137 			" access for LUN in Demo Mode\n",
138 			tpg->se_tpg_tfo->fabric_name,
139 			tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
140 			lun_access_ro ? "READ-ONLY" : "READ-WRITE");
141 
142 		core_enable_device_list_for_node(lun, NULL, lun->unpacked_lun,
143 						 lun_access_ro, acl, tpg);
144 		/*
145 		 * Check to see if there are any existing persistent reservation
146 		 * APTPL pre-registrations that need to be enabled for this dynamic
147 		 * LUN ACL now..
148 		 */
149 		core_scsi3_check_aptpl_registration(dev, tpg, lun, acl,
150 						    lun->unpacked_lun);
151 	}
152 	mutex_unlock(&tpg->tpg_lun_mutex);
153 }
154 
155 static void
156 target_set_nacl_queue_depth(struct se_portal_group *tpg,
157 			    struct se_node_acl *acl, u32 queue_depth)
158 {
159 	acl->queue_depth = queue_depth;
160 
161 	if (!acl->queue_depth) {
162 		pr_warn("Queue depth for %s Initiator Node: %s is 0,"
163 			"defaulting to 1.\n", tpg->se_tpg_tfo->fabric_name,
164 			acl->initiatorname);
165 		acl->queue_depth = 1;
166 	}
167 }
168 
169 static struct se_node_acl *target_alloc_node_acl(struct se_portal_group *tpg,
170 		const unsigned char *initiatorname)
171 {
172 	struct se_node_acl *acl;
173 	u32 queue_depth;
174 
175 	acl = kzalloc(max(sizeof(*acl), tpg->se_tpg_tfo->node_acl_size),
176 			GFP_KERNEL);
177 	if (!acl)
178 		return NULL;
179 
180 	INIT_LIST_HEAD(&acl->acl_list);
181 	INIT_LIST_HEAD(&acl->acl_sess_list);
182 	INIT_HLIST_HEAD(&acl->lun_entry_hlist);
183 	kref_init(&acl->acl_kref);
184 	init_completion(&acl->acl_free_comp);
185 	spin_lock_init(&acl->nacl_sess_lock);
186 	mutex_init(&acl->lun_entry_mutex);
187 	atomic_set(&acl->acl_pr_ref_count, 0);
188 
189 	if (tpg->se_tpg_tfo->tpg_get_default_depth)
190 		queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg);
191 	else
192 		queue_depth = 1;
193 	target_set_nacl_queue_depth(tpg, acl, queue_depth);
194 
195 	snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname);
196 	acl->se_tpg = tpg;
197 	acl->acl_index = scsi_get_new_index(SCSI_AUTH_INTR_INDEX);
198 
199 	tpg->se_tpg_tfo->set_default_node_attributes(acl);
200 
201 	return acl;
202 }
203 
204 static void target_add_node_acl(struct se_node_acl *acl)
205 {
206 	struct se_portal_group *tpg = acl->se_tpg;
207 
208 	mutex_lock(&tpg->acl_node_mutex);
209 	list_add_tail(&acl->acl_list, &tpg->acl_node_list);
210 	mutex_unlock(&tpg->acl_node_mutex);
211 
212 	pr_debug("%s_TPG[%hu] - Added %s ACL with TCQ Depth: %d for %s"
213 		" Initiator Node: %s\n",
214 		tpg->se_tpg_tfo->fabric_name,
215 		tpg->se_tpg_tfo->tpg_get_tag(tpg),
216 		acl->dynamic_node_acl ? "DYNAMIC" : "",
217 		acl->queue_depth,
218 		tpg->se_tpg_tfo->fabric_name,
219 		acl->initiatorname);
220 }
221 
222 bool target_tpg_has_node_acl(struct se_portal_group *tpg,
223 			     const char *initiatorname)
224 {
225 	struct se_node_acl *acl;
226 	bool found = false;
227 
228 	mutex_lock(&tpg->acl_node_mutex);
229 	list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
230 		if (!strcmp(acl->initiatorname, initiatorname)) {
231 			found = true;
232 			break;
233 		}
234 	}
235 	mutex_unlock(&tpg->acl_node_mutex);
236 
237 	return found;
238 }
239 EXPORT_SYMBOL(target_tpg_has_node_acl);
240 
241 struct se_node_acl *core_tpg_check_initiator_node_acl(
242 	struct se_portal_group *tpg,
243 	unsigned char *initiatorname)
244 {
245 	struct se_node_acl *acl;
246 
247 	acl = core_tpg_get_initiator_node_acl(tpg, initiatorname);
248 	if (acl)
249 		return acl;
250 
251 	if (!tpg->se_tpg_tfo->tpg_check_demo_mode(tpg))
252 		return NULL;
253 
254 	acl = target_alloc_node_acl(tpg, initiatorname);
255 	if (!acl)
256 		return NULL;
257 	/*
258 	 * When allocating a dynamically generated node_acl, go ahead
259 	 * and take the extra kref now before returning to the fabric
260 	 * driver caller.
261 	 *
262 	 * Note this reference will be released at session shutdown
263 	 * time within transport_free_session() code.
264 	 */
265 	kref_get(&acl->acl_kref);
266 	acl->dynamic_node_acl = 1;
267 
268 	/*
269 	 * Here we only create demo-mode MappedLUNs from the active
270 	 * TPG LUNs if the fabric is not explicitly asking for
271 	 * tpg_check_demo_mode_login_only() == 1.
272 	 */
273 	if ((tpg->se_tpg_tfo->tpg_check_demo_mode_login_only == NULL) ||
274 	    (tpg->se_tpg_tfo->tpg_check_demo_mode_login_only(tpg) != 1))
275 		core_tpg_add_node_to_devs(acl, tpg, NULL);
276 
277 	target_add_node_acl(acl);
278 	return acl;
279 }
280 EXPORT_SYMBOL(core_tpg_check_initiator_node_acl);
281 
282 void core_tpg_wait_for_nacl_pr_ref(struct se_node_acl *nacl)
283 {
284 	while (atomic_read(&nacl->acl_pr_ref_count) != 0)
285 		cpu_relax();
286 }
287 
288 struct se_node_acl *core_tpg_add_initiator_node_acl(
289 	struct se_portal_group *tpg,
290 	const char *initiatorname)
291 {
292 	struct se_node_acl *acl;
293 
294 	mutex_lock(&tpg->acl_node_mutex);
295 	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
296 	if (acl) {
297 		if (acl->dynamic_node_acl) {
298 			acl->dynamic_node_acl = 0;
299 			pr_debug("%s_TPG[%u] - Replacing dynamic ACL"
300 				" for %s\n", tpg->se_tpg_tfo->fabric_name,
301 				tpg->se_tpg_tfo->tpg_get_tag(tpg), initiatorname);
302 			mutex_unlock(&tpg->acl_node_mutex);
303 			return acl;
304 		}
305 
306 		pr_err("ACL entry for %s Initiator"
307 			" Node %s already exists for TPG %u, ignoring"
308 			" request.\n",  tpg->se_tpg_tfo->fabric_name,
309 			initiatorname, tpg->se_tpg_tfo->tpg_get_tag(tpg));
310 		mutex_unlock(&tpg->acl_node_mutex);
311 		return ERR_PTR(-EEXIST);
312 	}
313 	mutex_unlock(&tpg->acl_node_mutex);
314 
315 	acl = target_alloc_node_acl(tpg, initiatorname);
316 	if (!acl)
317 		return ERR_PTR(-ENOMEM);
318 
319 	target_add_node_acl(acl);
320 	return acl;
321 }
322 
323 static void target_shutdown_sessions(struct se_node_acl *acl)
324 {
325 	struct se_session *sess;
326 	unsigned long flags;
327 
328 restart:
329 	spin_lock_irqsave(&acl->nacl_sess_lock, flags);
330 	list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
331 		if (sess->sess_tearing_down)
332 			continue;
333 
334 		list_del_init(&sess->sess_acl_list);
335 		spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
336 
337 		if (acl->se_tpg->se_tpg_tfo->close_session)
338 			acl->se_tpg->se_tpg_tfo->close_session(sess);
339 		goto restart;
340 	}
341 	spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
342 }
343 
344 void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
345 {
346 	struct se_portal_group *tpg = acl->se_tpg;
347 
348 	mutex_lock(&tpg->acl_node_mutex);
349 	if (acl->dynamic_node_acl)
350 		acl->dynamic_node_acl = 0;
351 	list_del_init(&acl->acl_list);
352 	mutex_unlock(&tpg->acl_node_mutex);
353 
354 	target_shutdown_sessions(acl);
355 
356 	target_put_nacl(acl);
357 	/*
358 	 * Wait for last target_put_nacl() to complete in target_complete_nacl()
359 	 * for active fabric session transport_deregister_session() callbacks.
360 	 */
361 	wait_for_completion(&acl->acl_free_comp);
362 
363 	core_tpg_wait_for_nacl_pr_ref(acl);
364 	core_free_device_list_for_node(acl, tpg);
365 
366 	pr_debug("%s_TPG[%hu] - Deleted ACL with TCQ Depth: %d for %s"
367 		" Initiator Node: %s\n", tpg->se_tpg_tfo->fabric_name,
368 		tpg->se_tpg_tfo->tpg_get_tag(tpg), acl->queue_depth,
369 		tpg->se_tpg_tfo->fabric_name, acl->initiatorname);
370 
371 	kfree(acl);
372 }
373 
374 /*	core_tpg_set_initiator_node_queue_depth():
375  *
376  *
377  */
378 int core_tpg_set_initiator_node_queue_depth(
379 	struct se_node_acl *acl,
380 	u32 queue_depth)
381 {
382 	struct se_portal_group *tpg = acl->se_tpg;
383 
384 	/*
385 	 * Allow the setting of se_node_acl queue_depth to be idempotent,
386 	 * and not force a session shutdown event if the value is not
387 	 * changing.
388 	 */
389 	if (acl->queue_depth == queue_depth)
390 		return 0;
391 	/*
392 	 * User has requested to change the queue depth for a Initiator Node.
393 	 * Change the value in the Node's struct se_node_acl, and call
394 	 * target_set_nacl_queue_depth() to set the new queue depth.
395 	 */
396 	target_set_nacl_queue_depth(tpg, acl, queue_depth);
397 
398 	/*
399 	 * Shutdown all pending sessions to force session reinstatement.
400 	 */
401 	target_shutdown_sessions(acl);
402 
403 	pr_debug("Successfully changed queue depth to: %d for Initiator"
404 		" Node: %s on %s Target Portal Group: %u\n", acl->queue_depth,
405 		acl->initiatorname, tpg->se_tpg_tfo->fabric_name,
406 		tpg->se_tpg_tfo->tpg_get_tag(tpg));
407 
408 	return 0;
409 }
410 EXPORT_SYMBOL(core_tpg_set_initiator_node_queue_depth);
411 
412 /*	core_tpg_set_initiator_node_tag():
413  *
414  *	Initiator nodeacl tags are not used internally, but may be used by
415  *	userspace to emulate aliases or groups.
416  *	Returns length of newly-set tag or -EINVAL.
417  */
418 int core_tpg_set_initiator_node_tag(
419 	struct se_portal_group *tpg,
420 	struct se_node_acl *acl,
421 	const char *new_tag)
422 {
423 	if (strlen(new_tag) >= MAX_ACL_TAG_SIZE)
424 		return -EINVAL;
425 
426 	if (!strncmp("NULL", new_tag, 4)) {
427 		acl->acl_tag[0] = '\0';
428 		return 0;
429 	}
430 
431 	return snprintf(acl->acl_tag, MAX_ACL_TAG_SIZE, "%s", new_tag);
432 }
433 EXPORT_SYMBOL(core_tpg_set_initiator_node_tag);
434 
435 static void core_tpg_lun_ref_release(struct percpu_ref *ref)
436 {
437 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
438 
439 	complete(&lun->lun_shutdown_comp);
440 }
441 
442 /* Does not change se_wwn->priv. */
443 int core_tpg_register(
444 	struct se_wwn *se_wwn,
445 	struct se_portal_group *se_tpg,
446 	int proto_id)
447 {
448 	int ret;
449 
450 	if (!se_tpg)
451 		return -EINVAL;
452 	/*
453 	 * For the typical case where core_tpg_register() is called by a
454 	 * fabric driver from target_core_fabric_ops->fabric_make_tpg()
455 	 * configfs context, use the original tf_ops pointer already saved
456 	 * by target-core in target_fabric_make_wwn().
457 	 *
458 	 * Otherwise, for special cases like iscsi-target discovery TPGs
459 	 * the caller is responsible for setting ->se_tpg_tfo ahead of
460 	 * calling core_tpg_register().
461 	 */
462 	if (se_wwn)
463 		se_tpg->se_tpg_tfo = se_wwn->wwn_tf->tf_ops;
464 
465 	if (!se_tpg->se_tpg_tfo) {
466 		pr_err("Unable to locate se_tpg->se_tpg_tfo pointer\n");
467 		return -EINVAL;
468 	}
469 
470 	INIT_HLIST_HEAD(&se_tpg->tpg_lun_hlist);
471 	se_tpg->proto_id = proto_id;
472 	se_tpg->se_tpg_wwn = se_wwn;
473 	atomic_set(&se_tpg->tpg_pr_ref_count, 0);
474 	INIT_LIST_HEAD(&se_tpg->acl_node_list);
475 	INIT_LIST_HEAD(&se_tpg->tpg_sess_list);
476 	spin_lock_init(&se_tpg->session_lock);
477 	mutex_init(&se_tpg->tpg_lun_mutex);
478 	mutex_init(&se_tpg->acl_node_mutex);
479 
480 	if (se_tpg->proto_id >= 0) {
481 		se_tpg->tpg_virt_lun0 = core_tpg_alloc_lun(se_tpg, 0);
482 		if (IS_ERR(se_tpg->tpg_virt_lun0))
483 			return PTR_ERR(se_tpg->tpg_virt_lun0);
484 
485 		ret = core_tpg_add_lun(se_tpg, se_tpg->tpg_virt_lun0,
486 				true, g_lun0_dev);
487 		if (ret < 0) {
488 			kfree(se_tpg->tpg_virt_lun0);
489 			return ret;
490 		}
491 	}
492 
493 	pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
494 		 "Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->fabric_name,
495 		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) ?
496 		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) : NULL,
497 		se_tpg->proto_id, se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
498 
499 	return 0;
500 }
501 EXPORT_SYMBOL(core_tpg_register);
502 
503 int core_tpg_deregister(struct se_portal_group *se_tpg)
504 {
505 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
506 	struct se_node_acl *nacl, *nacl_tmp;
507 	LIST_HEAD(node_list);
508 
509 	pr_debug("TARGET_CORE[%s]: Deallocating portal_group for endpoint: %s, "
510 		 "Proto: %d, Portal Tag: %u\n", tfo->fabric_name,
511 		tfo->tpg_get_wwn(se_tpg) ? tfo->tpg_get_wwn(se_tpg) : NULL,
512 		se_tpg->proto_id, tfo->tpg_get_tag(se_tpg));
513 
514 	while (atomic_read(&se_tpg->tpg_pr_ref_count) != 0)
515 		cpu_relax();
516 
517 	mutex_lock(&se_tpg->acl_node_mutex);
518 	list_splice_init(&se_tpg->acl_node_list, &node_list);
519 	mutex_unlock(&se_tpg->acl_node_mutex);
520 	/*
521 	 * Release any remaining demo-mode generated se_node_acl that have
522 	 * not been released because of TFO->tpg_check_demo_mode_cache() == 1
523 	 * in transport_deregister_session().
524 	 */
525 	list_for_each_entry_safe(nacl, nacl_tmp, &node_list, acl_list) {
526 		list_del_init(&nacl->acl_list);
527 
528 		core_tpg_wait_for_nacl_pr_ref(nacl);
529 		core_free_device_list_for_node(nacl, se_tpg);
530 		kfree(nacl);
531 	}
532 
533 	if (se_tpg->proto_id >= 0) {
534 		core_tpg_remove_lun(se_tpg, se_tpg->tpg_virt_lun0);
535 		kfree_rcu(se_tpg->tpg_virt_lun0, rcu_head);
536 	}
537 
538 	return 0;
539 }
540 EXPORT_SYMBOL(core_tpg_deregister);
541 
542 struct se_lun *core_tpg_alloc_lun(
543 	struct se_portal_group *tpg,
544 	u64 unpacked_lun)
545 {
546 	struct se_lun *lun;
547 
548 	lun = kzalloc(sizeof(*lun), GFP_KERNEL);
549 	if (!lun) {
550 		pr_err("Unable to allocate se_lun memory\n");
551 		return ERR_PTR(-ENOMEM);
552 	}
553 	lun->unpacked_lun = unpacked_lun;
554 	atomic_set(&lun->lun_acl_count, 0);
555 	init_completion(&lun->lun_shutdown_comp);
556 	INIT_LIST_HEAD(&lun->lun_deve_list);
557 	INIT_LIST_HEAD(&lun->lun_dev_link);
558 	atomic_set(&lun->lun_tg_pt_secondary_offline, 0);
559 	spin_lock_init(&lun->lun_deve_lock);
560 	mutex_init(&lun->lun_tg_pt_md_mutex);
561 	INIT_LIST_HEAD(&lun->lun_tg_pt_gp_link);
562 	spin_lock_init(&lun->lun_tg_pt_gp_lock);
563 	lun->lun_tpg = tpg;
564 
565 	return lun;
566 }
567 
568 int core_tpg_add_lun(
569 	struct se_portal_group *tpg,
570 	struct se_lun *lun,
571 	bool lun_access_ro,
572 	struct se_device *dev)
573 {
574 	int ret;
575 
576 	ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release, 0,
577 			      GFP_KERNEL);
578 	if (ret < 0)
579 		goto out;
580 
581 	ret = core_alloc_rtpi(lun, dev);
582 	if (ret)
583 		goto out_kill_ref;
584 
585 	if (!(dev->transport->transport_flags &
586 	     TRANSPORT_FLAG_PASSTHROUGH_ALUA) &&
587 	    !(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
588 		target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp);
589 
590 	mutex_lock(&tpg->tpg_lun_mutex);
591 
592 	spin_lock(&dev->se_port_lock);
593 	lun->lun_index = dev->dev_index;
594 	rcu_assign_pointer(lun->lun_se_dev, dev);
595 	dev->export_count++;
596 	list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
597 	spin_unlock(&dev->se_port_lock);
598 
599 	if (dev->dev_flags & DF_READ_ONLY)
600 		lun->lun_access_ro = true;
601 	else
602 		lun->lun_access_ro = lun_access_ro;
603 	if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
604 		hlist_add_head_rcu(&lun->link, &tpg->tpg_lun_hlist);
605 	mutex_unlock(&tpg->tpg_lun_mutex);
606 
607 	return 0;
608 
609 out_kill_ref:
610 	percpu_ref_exit(&lun->lun_ref);
611 out:
612 	return ret;
613 }
614 
615 void core_tpg_remove_lun(
616 	struct se_portal_group *tpg,
617 	struct se_lun *lun)
618 {
619 	/*
620 	 * rcu_dereference_raw protected by se_lun->lun_group symlink
621 	 * reference to se_device->dev_group.
622 	 */
623 	struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);
624 
625 	lun->lun_shutdown = true;
626 
627 	core_clear_lun_from_tpg(lun, tpg);
628 	/*
629 	 * Wait for any active I/O references to percpu se_lun->lun_ref to
630 	 * be released.  Also, se_lun->lun_ref is now used by PR and ALUA
631 	 * logic when referencing a remote target port during ALL_TGT_PT=1
632 	 * and generating UNIT_ATTENTIONs for ALUA access state transition.
633 	 */
634 	transport_clear_lun_ref(lun);
635 
636 	mutex_lock(&tpg->tpg_lun_mutex);
637 	if (lun->lun_se_dev) {
638 		target_detach_tg_pt_gp(lun);
639 
640 		spin_lock(&dev->se_port_lock);
641 		list_del(&lun->lun_dev_link);
642 		dev->export_count--;
643 		rcu_assign_pointer(lun->lun_se_dev, NULL);
644 		spin_unlock(&dev->se_port_lock);
645 	}
646 	if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
647 		hlist_del_rcu(&lun->link);
648 
649 	lun->lun_shutdown = false;
650 	mutex_unlock(&tpg->tpg_lun_mutex);
651 
652 	percpu_ref_exit(&lun->lun_ref);
653 }
654