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 static DEFINE_SPINLOCK(tpg_lock);
36 static LIST_HEAD(tpg_list);
37 
38 /*	__core_tpg_get_initiator_node_acl():
39  *
40  *	mutex_lock(&tpg->acl_node_mutex); must be held when calling
41  */
42 struct se_node_acl *__core_tpg_get_initiator_node_acl(
43 	struct se_portal_group *tpg,
44 	const char *initiatorname)
45 {
46 	struct se_node_acl *acl;
47 
48 	list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
49 		if (!strcmp(acl->initiatorname, initiatorname))
50 			return acl;
51 	}
52 
53 	return NULL;
54 }
55 
56 /*	core_tpg_get_initiator_node_acl():
57  *
58  *
59  */
60 struct se_node_acl *core_tpg_get_initiator_node_acl(
61 	struct se_portal_group *tpg,
62 	unsigned char *initiatorname)
63 {
64 	struct se_node_acl *acl;
65 	/*
66 	 * Obtain se_node_acl->acl_kref using fabric driver provided
67 	 * initiatorname[] during node acl endpoint lookup driven by
68 	 * new se_session login.
69 	 *
70 	 * The reference is held until se_session shutdown -> release
71 	 * occurs via fabric driver invoked transport_deregister_session()
72 	 * or transport_free_session() code.
73 	 */
74 	mutex_lock(&tpg->acl_node_mutex);
75 	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
76 	if (acl) {
77 		if (!kref_get_unless_zero(&acl->acl_kref))
78 			acl = NULL;
79 	}
80 	mutex_unlock(&tpg->acl_node_mutex);
81 
82 	return acl;
83 }
84 EXPORT_SYMBOL(core_tpg_get_initiator_node_acl);
85 
86 void core_allocate_nexus_loss_ua(
87 	struct se_node_acl *nacl)
88 {
89 	struct se_dev_entry *deve;
90 
91 	if (!nacl)
92 		return;
93 
94 	rcu_read_lock();
95 	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
96 		core_scsi3_ua_allocate(deve, 0x29,
97 			ASCQ_29H_NEXUS_LOSS_OCCURRED);
98 	rcu_read_unlock();
99 }
100 EXPORT_SYMBOL(core_allocate_nexus_loss_ua);
101 
102 /*	core_tpg_add_node_to_devs():
103  *
104  *
105  */
106 void core_tpg_add_node_to_devs(
107 	struct se_node_acl *acl,
108 	struct se_portal_group *tpg,
109 	struct se_lun *lun_orig)
110 {
111 	bool lun_access_ro = true;
112 	struct se_lun *lun;
113 	struct se_device *dev;
114 
115 	mutex_lock(&tpg->tpg_lun_mutex);
116 	hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
117 		if (lun_orig && lun != lun_orig)
118 			continue;
119 
120 		dev = rcu_dereference_check(lun->lun_se_dev,
121 					    lockdep_is_held(&tpg->tpg_lun_mutex));
122 		/*
123 		 * By default in LIO-Target $FABRIC_MOD,
124 		 * demo_mode_write_protect is ON, or READ_ONLY;
125 		 */
126 		if (!tpg->se_tpg_tfo->tpg_check_demo_mode_write_protect(tpg)) {
127 			lun_access_ro = false;
128 		} else {
129 			/*
130 			 * Allow only optical drives to issue R/W in default RO
131 			 * demo mode.
132 			 */
133 			if (dev->transport->get_device_type(dev) == TYPE_DISK)
134 				lun_access_ro = true;
135 			else
136 				lun_access_ro = false;
137 		}
138 
139 		pr_debug("TARGET_CORE[%s]->TPG[%u]_LUN[%llu] - Adding %s"
140 			" access for LUN in Demo Mode\n",
141 			tpg->se_tpg_tfo->fabric_name,
142 			tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
143 			lun_access_ro ? "READ-ONLY" : "READ-WRITE");
144 
145 		core_enable_device_list_for_node(lun, NULL, lun->unpacked_lun,
146 						 lun_access_ro, acl, tpg);
147 		/*
148 		 * Check to see if there are any existing persistent reservation
149 		 * APTPL pre-registrations that need to be enabled for this dynamic
150 		 * LUN ACL now..
151 		 */
152 		core_scsi3_check_aptpl_registration(dev, tpg, lun, acl,
153 						    lun->unpacked_lun);
154 	}
155 	mutex_unlock(&tpg->tpg_lun_mutex);
156 }
157 
158 static void
159 target_set_nacl_queue_depth(struct se_portal_group *tpg,
160 			    struct se_node_acl *acl, u32 queue_depth)
161 {
162 	acl->queue_depth = queue_depth;
163 
164 	if (!acl->queue_depth) {
165 		pr_warn("Queue depth for %s Initiator Node: %s is 0,"
166 			"defaulting to 1.\n", tpg->se_tpg_tfo->fabric_name,
167 			acl->initiatorname);
168 		acl->queue_depth = 1;
169 	}
170 }
171 
172 static struct se_node_acl *target_alloc_node_acl(struct se_portal_group *tpg,
173 		const unsigned char *initiatorname)
174 {
175 	struct se_node_acl *acl;
176 	u32 queue_depth;
177 
178 	acl = kzalloc(max(sizeof(*acl), tpg->se_tpg_tfo->node_acl_size),
179 			GFP_KERNEL);
180 	if (!acl)
181 		return NULL;
182 
183 	INIT_LIST_HEAD(&acl->acl_list);
184 	INIT_LIST_HEAD(&acl->acl_sess_list);
185 	INIT_HLIST_HEAD(&acl->lun_entry_hlist);
186 	kref_init(&acl->acl_kref);
187 	init_completion(&acl->acl_free_comp);
188 	spin_lock_init(&acl->nacl_sess_lock);
189 	mutex_init(&acl->lun_entry_mutex);
190 	atomic_set(&acl->acl_pr_ref_count, 0);
191 
192 	if (tpg->se_tpg_tfo->tpg_get_default_depth)
193 		queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg);
194 	else
195 		queue_depth = 1;
196 	target_set_nacl_queue_depth(tpg, acl, queue_depth);
197 
198 	snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname);
199 	acl->se_tpg = tpg;
200 	acl->acl_index = scsi_get_new_index(SCSI_AUTH_INTR_INDEX);
201 
202 	tpg->se_tpg_tfo->set_default_node_attributes(acl);
203 
204 	return acl;
205 }
206 
207 static void target_add_node_acl(struct se_node_acl *acl)
208 {
209 	struct se_portal_group *tpg = acl->se_tpg;
210 
211 	mutex_lock(&tpg->acl_node_mutex);
212 	list_add_tail(&acl->acl_list, &tpg->acl_node_list);
213 	mutex_unlock(&tpg->acl_node_mutex);
214 
215 	pr_debug("%s_TPG[%hu] - Added %s ACL with TCQ Depth: %d for %s"
216 		" Initiator Node: %s\n",
217 		tpg->se_tpg_tfo->fabric_name,
218 		tpg->se_tpg_tfo->tpg_get_tag(tpg),
219 		acl->dynamic_node_acl ? "DYNAMIC" : "",
220 		acl->queue_depth,
221 		tpg->se_tpg_tfo->fabric_name,
222 		acl->initiatorname);
223 }
224 
225 bool target_tpg_has_node_acl(struct se_portal_group *tpg,
226 			     const char *initiatorname)
227 {
228 	struct se_node_acl *acl;
229 	bool found = false;
230 
231 	mutex_lock(&tpg->acl_node_mutex);
232 	list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
233 		if (!strcmp(acl->initiatorname, initiatorname)) {
234 			found = true;
235 			break;
236 		}
237 	}
238 	mutex_unlock(&tpg->acl_node_mutex);
239 
240 	return found;
241 }
242 EXPORT_SYMBOL(target_tpg_has_node_acl);
243 
244 struct se_node_acl *core_tpg_check_initiator_node_acl(
245 	struct se_portal_group *tpg,
246 	unsigned char *initiatorname)
247 {
248 	struct se_node_acl *acl;
249 
250 	acl = core_tpg_get_initiator_node_acl(tpg, initiatorname);
251 	if (acl)
252 		return acl;
253 
254 	if (!tpg->se_tpg_tfo->tpg_check_demo_mode(tpg))
255 		return NULL;
256 
257 	acl = target_alloc_node_acl(tpg, initiatorname);
258 	if (!acl)
259 		return NULL;
260 	/*
261 	 * When allocating a dynamically generated node_acl, go ahead
262 	 * and take the extra kref now before returning to the fabric
263 	 * driver caller.
264 	 *
265 	 * Note this reference will be released at session shutdown
266 	 * time within transport_free_session() code.
267 	 */
268 	kref_get(&acl->acl_kref);
269 	acl->dynamic_node_acl = 1;
270 
271 	/*
272 	 * Here we only create demo-mode MappedLUNs from the active
273 	 * TPG LUNs if the fabric is not explicitly asking for
274 	 * tpg_check_demo_mode_login_only() == 1.
275 	 */
276 	if ((tpg->se_tpg_tfo->tpg_check_demo_mode_login_only == NULL) ||
277 	    (tpg->se_tpg_tfo->tpg_check_demo_mode_login_only(tpg) != 1))
278 		core_tpg_add_node_to_devs(acl, tpg, NULL);
279 
280 	target_add_node_acl(acl);
281 	return acl;
282 }
283 EXPORT_SYMBOL(core_tpg_check_initiator_node_acl);
284 
285 void core_tpg_wait_for_nacl_pr_ref(struct se_node_acl *nacl)
286 {
287 	while (atomic_read(&nacl->acl_pr_ref_count) != 0)
288 		cpu_relax();
289 }
290 
291 struct se_node_acl *core_tpg_add_initiator_node_acl(
292 	struct se_portal_group *tpg,
293 	const char *initiatorname)
294 {
295 	struct se_node_acl *acl;
296 
297 	mutex_lock(&tpg->acl_node_mutex);
298 	acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
299 	if (acl) {
300 		if (acl->dynamic_node_acl) {
301 			acl->dynamic_node_acl = 0;
302 			pr_debug("%s_TPG[%u] - Replacing dynamic ACL"
303 				" for %s\n", tpg->se_tpg_tfo->fabric_name,
304 				tpg->se_tpg_tfo->tpg_get_tag(tpg), initiatorname);
305 			mutex_unlock(&tpg->acl_node_mutex);
306 			return acl;
307 		}
308 
309 		pr_err("ACL entry for %s Initiator"
310 			" Node %s already exists for TPG %u, ignoring"
311 			" request.\n",  tpg->se_tpg_tfo->fabric_name,
312 			initiatorname, tpg->se_tpg_tfo->tpg_get_tag(tpg));
313 		mutex_unlock(&tpg->acl_node_mutex);
314 		return ERR_PTR(-EEXIST);
315 	}
316 	mutex_unlock(&tpg->acl_node_mutex);
317 
318 	acl = target_alloc_node_acl(tpg, initiatorname);
319 	if (!acl)
320 		return ERR_PTR(-ENOMEM);
321 
322 	target_add_node_acl(acl);
323 	return acl;
324 }
325 
326 static void target_shutdown_sessions(struct se_node_acl *acl)
327 {
328 	struct se_session *sess;
329 	unsigned long flags;
330 
331 restart:
332 	spin_lock_irqsave(&acl->nacl_sess_lock, flags);
333 	list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
334 		if (sess->sess_tearing_down)
335 			continue;
336 
337 		list_del_init(&sess->sess_acl_list);
338 		spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
339 
340 		if (acl->se_tpg->se_tpg_tfo->close_session)
341 			acl->se_tpg->se_tpg_tfo->close_session(sess);
342 		goto restart;
343 	}
344 	spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
345 }
346 
347 void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
348 {
349 	struct se_portal_group *tpg = acl->se_tpg;
350 
351 	mutex_lock(&tpg->acl_node_mutex);
352 	if (acl->dynamic_node_acl)
353 		acl->dynamic_node_acl = 0;
354 	list_del_init(&acl->acl_list);
355 	mutex_unlock(&tpg->acl_node_mutex);
356 
357 	target_shutdown_sessions(acl);
358 
359 	target_put_nacl(acl);
360 	/*
361 	 * Wait for last target_put_nacl() to complete in target_complete_nacl()
362 	 * for active fabric session transport_deregister_session() callbacks.
363 	 */
364 	wait_for_completion(&acl->acl_free_comp);
365 
366 	core_tpg_wait_for_nacl_pr_ref(acl);
367 	core_free_device_list_for_node(acl, tpg);
368 
369 	pr_debug("%s_TPG[%hu] - Deleted ACL with TCQ Depth: %d for %s"
370 		" Initiator Node: %s\n", tpg->se_tpg_tfo->fabric_name,
371 		tpg->se_tpg_tfo->tpg_get_tag(tpg), acl->queue_depth,
372 		tpg->se_tpg_tfo->fabric_name, acl->initiatorname);
373 
374 	kfree(acl);
375 }
376 
377 /*	core_tpg_set_initiator_node_queue_depth():
378  *
379  *
380  */
381 int core_tpg_set_initiator_node_queue_depth(
382 	struct se_node_acl *acl,
383 	u32 queue_depth)
384 {
385 	struct se_portal_group *tpg = acl->se_tpg;
386 
387 	/*
388 	 * Allow the setting of se_node_acl queue_depth to be idempotent,
389 	 * and not force a session shutdown event if the value is not
390 	 * changing.
391 	 */
392 	if (acl->queue_depth == queue_depth)
393 		return 0;
394 	/*
395 	 * User has requested to change the queue depth for a Initiator Node.
396 	 * Change the value in the Node's struct se_node_acl, and call
397 	 * target_set_nacl_queue_depth() to set the new queue depth.
398 	 */
399 	target_set_nacl_queue_depth(tpg, acl, queue_depth);
400 
401 	/*
402 	 * Shutdown all pending sessions to force session reinstatement.
403 	 */
404 	target_shutdown_sessions(acl);
405 
406 	pr_debug("Successfully changed queue depth to: %d for Initiator"
407 		" Node: %s on %s Target Portal Group: %u\n", acl->queue_depth,
408 		acl->initiatorname, tpg->se_tpg_tfo->fabric_name,
409 		tpg->se_tpg_tfo->tpg_get_tag(tpg));
410 
411 	return 0;
412 }
413 EXPORT_SYMBOL(core_tpg_set_initiator_node_queue_depth);
414 
415 /*	core_tpg_set_initiator_node_tag():
416  *
417  *	Initiator nodeacl tags are not used internally, but may be used by
418  *	userspace to emulate aliases or groups.
419  *	Returns length of newly-set tag or -EINVAL.
420  */
421 int core_tpg_set_initiator_node_tag(
422 	struct se_portal_group *tpg,
423 	struct se_node_acl *acl,
424 	const char *new_tag)
425 {
426 	if (strlen(new_tag) >= MAX_ACL_TAG_SIZE)
427 		return -EINVAL;
428 
429 	if (!strncmp("NULL", new_tag, 4)) {
430 		acl->acl_tag[0] = '\0';
431 		return 0;
432 	}
433 
434 	return snprintf(acl->acl_tag, MAX_ACL_TAG_SIZE, "%s", new_tag);
435 }
436 EXPORT_SYMBOL(core_tpg_set_initiator_node_tag);
437 
438 static void core_tpg_lun_ref_release(struct percpu_ref *ref)
439 {
440 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
441 
442 	complete(&lun->lun_shutdown_comp);
443 }
444 
445 /* Does not change se_wwn->priv. */
446 int core_tpg_register(
447 	struct se_wwn *se_wwn,
448 	struct se_portal_group *se_tpg,
449 	int proto_id)
450 {
451 	int ret;
452 
453 	if (!se_tpg)
454 		return -EINVAL;
455 	/*
456 	 * For the typical case where core_tpg_register() is called by a
457 	 * fabric driver from target_core_fabric_ops->fabric_make_tpg()
458 	 * configfs context, use the original tf_ops pointer already saved
459 	 * by target-core in target_fabric_make_wwn().
460 	 *
461 	 * Otherwise, for special cases like iscsi-target discovery TPGs
462 	 * the caller is responsible for setting ->se_tpg_tfo ahead of
463 	 * calling core_tpg_register().
464 	 */
465 	if (se_wwn)
466 		se_tpg->se_tpg_tfo = se_wwn->wwn_tf->tf_ops;
467 
468 	if (!se_tpg->se_tpg_tfo) {
469 		pr_err("Unable to locate se_tpg->se_tpg_tfo pointer\n");
470 		return -EINVAL;
471 	}
472 
473 	INIT_HLIST_HEAD(&se_tpg->tpg_lun_hlist);
474 	se_tpg->proto_id = proto_id;
475 	se_tpg->se_tpg_wwn = se_wwn;
476 	atomic_set(&se_tpg->tpg_pr_ref_count, 0);
477 	INIT_LIST_HEAD(&se_tpg->acl_node_list);
478 	INIT_LIST_HEAD(&se_tpg->se_tpg_node);
479 	INIT_LIST_HEAD(&se_tpg->tpg_sess_list);
480 	spin_lock_init(&se_tpg->session_lock);
481 	mutex_init(&se_tpg->tpg_lun_mutex);
482 	mutex_init(&se_tpg->acl_node_mutex);
483 
484 	if (se_tpg->proto_id >= 0) {
485 		se_tpg->tpg_virt_lun0 = core_tpg_alloc_lun(se_tpg, 0);
486 		if (IS_ERR(se_tpg->tpg_virt_lun0))
487 			return PTR_ERR(se_tpg->tpg_virt_lun0);
488 
489 		ret = core_tpg_add_lun(se_tpg, se_tpg->tpg_virt_lun0,
490 				true, g_lun0_dev);
491 		if (ret < 0) {
492 			kfree(se_tpg->tpg_virt_lun0);
493 			return ret;
494 		}
495 	}
496 
497 	spin_lock_bh(&tpg_lock);
498 	list_add_tail(&se_tpg->se_tpg_node, &tpg_list);
499 	spin_unlock_bh(&tpg_lock);
500 
501 	pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
502 		 "Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->fabric_name,
503 		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) ?
504 		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) : NULL,
505 		se_tpg->proto_id, se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
506 
507 	return 0;
508 }
509 EXPORT_SYMBOL(core_tpg_register);
510 
511 int core_tpg_deregister(struct se_portal_group *se_tpg)
512 {
513 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
514 	struct se_node_acl *nacl, *nacl_tmp;
515 	LIST_HEAD(node_list);
516 
517 	pr_debug("TARGET_CORE[%s]: Deallocating portal_group for endpoint: %s, "
518 		 "Proto: %d, Portal Tag: %u\n", tfo->fabric_name,
519 		tfo->tpg_get_wwn(se_tpg) ? tfo->tpg_get_wwn(se_tpg) : NULL,
520 		se_tpg->proto_id, tfo->tpg_get_tag(se_tpg));
521 
522 	spin_lock_bh(&tpg_lock);
523 	list_del(&se_tpg->se_tpg_node);
524 	spin_unlock_bh(&tpg_lock);
525 
526 	while (atomic_read(&se_tpg->tpg_pr_ref_count) != 0)
527 		cpu_relax();
528 
529 	mutex_lock(&se_tpg->acl_node_mutex);
530 	list_splice_init(&se_tpg->acl_node_list, &node_list);
531 	mutex_unlock(&se_tpg->acl_node_mutex);
532 	/*
533 	 * Release any remaining demo-mode generated se_node_acl that have
534 	 * not been released because of TFO->tpg_check_demo_mode_cache() == 1
535 	 * in transport_deregister_session().
536 	 */
537 	list_for_each_entry_safe(nacl, nacl_tmp, &node_list, acl_list) {
538 		list_del_init(&nacl->acl_list);
539 
540 		core_tpg_wait_for_nacl_pr_ref(nacl);
541 		core_free_device_list_for_node(nacl, se_tpg);
542 		kfree(nacl);
543 	}
544 
545 	if (se_tpg->proto_id >= 0) {
546 		core_tpg_remove_lun(se_tpg, se_tpg->tpg_virt_lun0);
547 		kfree_rcu(se_tpg->tpg_virt_lun0, rcu_head);
548 	}
549 
550 	return 0;
551 }
552 EXPORT_SYMBOL(core_tpg_deregister);
553 
554 struct se_lun *core_tpg_alloc_lun(
555 	struct se_portal_group *tpg,
556 	u64 unpacked_lun)
557 {
558 	struct se_lun *lun;
559 
560 	lun = kzalloc(sizeof(*lun), GFP_KERNEL);
561 	if (!lun) {
562 		pr_err("Unable to allocate se_lun memory\n");
563 		return ERR_PTR(-ENOMEM);
564 	}
565 	lun->unpacked_lun = unpacked_lun;
566 	atomic_set(&lun->lun_acl_count, 0);
567 	init_completion(&lun->lun_shutdown_comp);
568 	INIT_LIST_HEAD(&lun->lun_deve_list);
569 	INIT_LIST_HEAD(&lun->lun_dev_link);
570 	atomic_set(&lun->lun_tg_pt_secondary_offline, 0);
571 	spin_lock_init(&lun->lun_deve_lock);
572 	mutex_init(&lun->lun_tg_pt_md_mutex);
573 	INIT_LIST_HEAD(&lun->lun_tg_pt_gp_link);
574 	spin_lock_init(&lun->lun_tg_pt_gp_lock);
575 	lun->lun_tpg = tpg;
576 
577 	return lun;
578 }
579 
580 int core_tpg_add_lun(
581 	struct se_portal_group *tpg,
582 	struct se_lun *lun,
583 	bool lun_access_ro,
584 	struct se_device *dev)
585 {
586 	int ret;
587 
588 	ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release, 0,
589 			      GFP_KERNEL);
590 	if (ret < 0)
591 		goto out;
592 
593 	ret = core_alloc_rtpi(lun, dev);
594 	if (ret)
595 		goto out_kill_ref;
596 
597 	if (!(dev->transport->transport_flags &
598 	     TRANSPORT_FLAG_PASSTHROUGH_ALUA) &&
599 	    !(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
600 		target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp);
601 
602 	mutex_lock(&tpg->tpg_lun_mutex);
603 
604 	spin_lock(&dev->se_port_lock);
605 	lun->lun_index = dev->dev_index;
606 	rcu_assign_pointer(lun->lun_se_dev, dev);
607 	dev->export_count++;
608 	list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
609 	spin_unlock(&dev->se_port_lock);
610 
611 	if (dev->dev_flags & DF_READ_ONLY)
612 		lun->lun_access_ro = true;
613 	else
614 		lun->lun_access_ro = lun_access_ro;
615 	if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
616 		hlist_add_head_rcu(&lun->link, &tpg->tpg_lun_hlist);
617 	mutex_unlock(&tpg->tpg_lun_mutex);
618 
619 	return 0;
620 
621 out_kill_ref:
622 	percpu_ref_exit(&lun->lun_ref);
623 out:
624 	return ret;
625 }
626 
627 void core_tpg_remove_lun(
628 	struct se_portal_group *tpg,
629 	struct se_lun *lun)
630 {
631 	/*
632 	 * rcu_dereference_raw protected by se_lun->lun_group symlink
633 	 * reference to se_device->dev_group.
634 	 */
635 	struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);
636 
637 	lun->lun_shutdown = true;
638 
639 	core_clear_lun_from_tpg(lun, tpg);
640 	/*
641 	 * Wait for any active I/O references to percpu se_lun->lun_ref to
642 	 * be released.  Also, se_lun->lun_ref is now used by PR and ALUA
643 	 * logic when referencing a remote target port during ALL_TGT_PT=1
644 	 * and generating UNIT_ATTENTIONs for ALUA access state transition.
645 	 */
646 	transport_clear_lun_ref(lun);
647 
648 	mutex_lock(&tpg->tpg_lun_mutex);
649 	if (lun->lun_se_dev) {
650 		target_detach_tg_pt_gp(lun);
651 
652 		spin_lock(&dev->se_port_lock);
653 		list_del(&lun->lun_dev_link);
654 		dev->export_count--;
655 		rcu_assign_pointer(lun->lun_se_dev, NULL);
656 		spin_unlock(&dev->se_port_lock);
657 	}
658 	if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
659 		hlist_del_rcu(&lun->link);
660 
661 	lun->lun_shutdown = false;
662 	mutex_unlock(&tpg->tpg_lun_mutex);
663 
664 	percpu_ref_exit(&lun->lun_ref);
665 }
666