summaryrefslogtreecommitdiff
path: root/drivers/target/target_core_tpg.c
blob: 4a8b180c478bce1917b469282733e01614e37178 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
/*******************************************************************************
 * 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;
	/*
	 * 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->get_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->get_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->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);
}

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->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;
}

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->sess_tearing_down)
			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(&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->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_node_acl *acl,
	u32 queue_depth)
{
	struct se_portal_group *tpg = acl->se_tpg;

	/*
	 * 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->get_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_ref_comp);
}

/* 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->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,
				true, 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);

		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,
	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;

	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_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_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);
}