Merge tag 'dm-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device...
[sfrench/cifs-2.6.git] / drivers / target / target_core_tpg.c
1 /*******************************************************************************
2  * Filename:  target_core_tpg.c
3  *
4  * This file contains generic Target Portal Group related functions.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25
26 #include <linux/net.h>
27 #include <linux/string.h>
28 #include <linux/timer.h>
29 #include <linux/slab.h>
30 #include <linux/spinlock.h>
31 #include <linux/in.h>
32 #include <linux/export.h>
33 #include <net/sock.h>
34 #include <net/tcp.h>
35 #include <scsi/scsi_proto.h>
36
37 #include <target/target_core_base.h>
38 #include <target/target_core_backend.h>
39 #include <target/target_core_fabric.h>
40
41 #include "target_core_internal.h"
42 #include "target_core_alua.h"
43 #include "target_core_pr.h"
44 #include "target_core_ua.h"
45
46 extern struct se_device *g_lun0_dev;
47
48 static DEFINE_SPINLOCK(tpg_lock);
49 static LIST_HEAD(tpg_list);
50
51 /*      __core_tpg_get_initiator_node_acl():
52  *
53  *      mutex_lock(&tpg->acl_node_mutex); must be held when calling
54  */
55 struct se_node_acl *__core_tpg_get_initiator_node_acl(
56         struct se_portal_group *tpg,
57         const char *initiatorname)
58 {
59         struct se_node_acl *acl;
60
61         list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
62                 if (!strcmp(acl->initiatorname, initiatorname))
63                         return acl;
64         }
65
66         return NULL;
67 }
68
69 /*      core_tpg_get_initiator_node_acl():
70  *
71  *
72  */
73 struct se_node_acl *core_tpg_get_initiator_node_acl(
74         struct se_portal_group *tpg,
75         unsigned char *initiatorname)
76 {
77         struct se_node_acl *acl;
78         /*
79          * Obtain se_node_acl->acl_kref using fabric driver provided
80          * initiatorname[] during node acl endpoint lookup driven by
81          * new se_session login.
82          *
83          * The reference is held until se_session shutdown -> release
84          * occurs via fabric driver invoked transport_deregister_session()
85          * or transport_free_session() code.
86          */
87         mutex_lock(&tpg->acl_node_mutex);
88         acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
89         if (acl) {
90                 if (!kref_get_unless_zero(&acl->acl_kref))
91                         acl = NULL;
92         }
93         mutex_unlock(&tpg->acl_node_mutex);
94
95         return acl;
96 }
97 EXPORT_SYMBOL(core_tpg_get_initiator_node_acl);
98
99 void core_allocate_nexus_loss_ua(
100         struct se_node_acl *nacl)
101 {
102         struct se_dev_entry *deve;
103
104         if (!nacl)
105                 return;
106
107         rcu_read_lock();
108         hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
109                 core_scsi3_ua_allocate(deve, 0x29,
110                         ASCQ_29H_NEXUS_LOSS_OCCURRED);
111         rcu_read_unlock();
112 }
113 EXPORT_SYMBOL(core_allocate_nexus_loss_ua);
114
115 /*      core_tpg_add_node_to_devs():
116  *
117  *
118  */
119 void core_tpg_add_node_to_devs(
120         struct se_node_acl *acl,
121         struct se_portal_group *tpg,
122         struct se_lun *lun_orig)
123 {
124         bool lun_access_ro = true;
125         struct se_lun *lun;
126         struct se_device *dev;
127
128         mutex_lock(&tpg->tpg_lun_mutex);
129         hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
130                 if (lun_orig && lun != lun_orig)
131                         continue;
132
133                 dev = rcu_dereference_check(lun->lun_se_dev,
134                                             lockdep_is_held(&tpg->tpg_lun_mutex));
135                 /*
136                  * By default in LIO-Target $FABRIC_MOD,
137                  * demo_mode_write_protect is ON, or READ_ONLY;
138                  */
139                 if (!tpg->se_tpg_tfo->tpg_check_demo_mode_write_protect(tpg)) {
140                         lun_access_ro = false;
141                 } else {
142                         /*
143                          * Allow only optical drives to issue R/W in default RO
144                          * demo mode.
145                          */
146                         if (dev->transport->get_device_type(dev) == TYPE_DISK)
147                                 lun_access_ro = true;
148                         else
149                                 lun_access_ro = false;
150                 }
151
152                 pr_debug("TARGET_CORE[%s]->TPG[%u]_LUN[%llu] - Adding %s"
153                         " access for LUN in Demo Mode\n",
154                         tpg->se_tpg_tfo->get_fabric_name(),
155                         tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
156                         lun_access_ro ? "READ-ONLY" : "READ-WRITE");
157
158                 core_enable_device_list_for_node(lun, NULL, lun->unpacked_lun,
159                                                  lun_access_ro, acl, tpg);
160                 /*
161                  * Check to see if there are any existing persistent reservation
162                  * APTPL pre-registrations that need to be enabled for this dynamic
163                  * LUN ACL now..
164                  */
165                 core_scsi3_check_aptpl_registration(dev, tpg, lun, acl,
166                                                     lun->unpacked_lun);
167         }
168         mutex_unlock(&tpg->tpg_lun_mutex);
169 }
170
171 static void
172 target_set_nacl_queue_depth(struct se_portal_group *tpg,
173                             struct se_node_acl *acl, u32 queue_depth)
174 {
175         acl->queue_depth = queue_depth;
176
177         if (!acl->queue_depth) {
178                 pr_warn("Queue depth for %s Initiator Node: %s is 0,"
179                         "defaulting to 1.\n", tpg->se_tpg_tfo->get_fabric_name(),
180                         acl->initiatorname);
181                 acl->queue_depth = 1;
182         }
183 }
184
185 static struct se_node_acl *target_alloc_node_acl(struct se_portal_group *tpg,
186                 const unsigned char *initiatorname)
187 {
188         struct se_node_acl *acl;
189         u32 queue_depth;
190
191         acl = kzalloc(max(sizeof(*acl), tpg->se_tpg_tfo->node_acl_size),
192                         GFP_KERNEL);
193         if (!acl)
194                 return NULL;
195
196         INIT_LIST_HEAD(&acl->acl_list);
197         INIT_LIST_HEAD(&acl->acl_sess_list);
198         INIT_HLIST_HEAD(&acl->lun_entry_hlist);
199         kref_init(&acl->acl_kref);
200         init_completion(&acl->acl_free_comp);
201         spin_lock_init(&acl->nacl_sess_lock);
202         mutex_init(&acl->lun_entry_mutex);
203         atomic_set(&acl->acl_pr_ref_count, 0);
204
205         if (tpg->se_tpg_tfo->tpg_get_default_depth)
206                 queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg);
207         else
208                 queue_depth = 1;
209         target_set_nacl_queue_depth(tpg, acl, queue_depth);
210
211         snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname);
212         acl->se_tpg = tpg;
213         acl->acl_index = scsi_get_new_index(SCSI_AUTH_INTR_INDEX);
214
215         tpg->se_tpg_tfo->set_default_node_attributes(acl);
216
217         return acl;
218 }
219
220 static void target_add_node_acl(struct se_node_acl *acl)
221 {
222         struct se_portal_group *tpg = acl->se_tpg;
223
224         mutex_lock(&tpg->acl_node_mutex);
225         list_add_tail(&acl->acl_list, &tpg->acl_node_list);
226         mutex_unlock(&tpg->acl_node_mutex);
227
228         pr_debug("%s_TPG[%hu] - Added %s ACL with TCQ Depth: %d for %s"
229                 " Initiator Node: %s\n",
230                 tpg->se_tpg_tfo->get_fabric_name(),
231                 tpg->se_tpg_tfo->tpg_get_tag(tpg),
232                 acl->dynamic_node_acl ? "DYNAMIC" : "",
233                 acl->queue_depth,
234                 tpg->se_tpg_tfo->get_fabric_name(),
235                 acl->initiatorname);
236 }
237
238 bool target_tpg_has_node_acl(struct se_portal_group *tpg,
239                              const char *initiatorname)
240 {
241         struct se_node_acl *acl;
242         bool found = false;
243
244         mutex_lock(&tpg->acl_node_mutex);
245         list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
246                 if (!strcmp(acl->initiatorname, initiatorname)) {
247                         found = true;
248                         break;
249                 }
250         }
251         mutex_unlock(&tpg->acl_node_mutex);
252
253         return found;
254 }
255 EXPORT_SYMBOL(target_tpg_has_node_acl);
256
257 struct se_node_acl *core_tpg_check_initiator_node_acl(
258         struct se_portal_group *tpg,
259         unsigned char *initiatorname)
260 {
261         struct se_node_acl *acl;
262
263         acl = core_tpg_get_initiator_node_acl(tpg, initiatorname);
264         if (acl)
265                 return acl;
266
267         if (!tpg->se_tpg_tfo->tpg_check_demo_mode(tpg))
268                 return NULL;
269
270         acl = target_alloc_node_acl(tpg, initiatorname);
271         if (!acl)
272                 return NULL;
273         /*
274          * When allocating a dynamically generated node_acl, go ahead
275          * and take the extra kref now before returning to the fabric
276          * driver caller.
277          *
278          * Note this reference will be released at session shutdown
279          * time within transport_free_session() code.
280          */
281         kref_get(&acl->acl_kref);
282         acl->dynamic_node_acl = 1;
283
284         /*
285          * Here we only create demo-mode MappedLUNs from the active
286          * TPG LUNs if the fabric is not explicitly asking for
287          * tpg_check_demo_mode_login_only() == 1.
288          */
289         if ((tpg->se_tpg_tfo->tpg_check_demo_mode_login_only == NULL) ||
290             (tpg->se_tpg_tfo->tpg_check_demo_mode_login_only(tpg) != 1))
291                 core_tpg_add_node_to_devs(acl, tpg, NULL);
292
293         target_add_node_acl(acl);
294         return acl;
295 }
296 EXPORT_SYMBOL(core_tpg_check_initiator_node_acl);
297
298 void core_tpg_wait_for_nacl_pr_ref(struct se_node_acl *nacl)
299 {
300         while (atomic_read(&nacl->acl_pr_ref_count) != 0)
301                 cpu_relax();
302 }
303
304 struct se_node_acl *core_tpg_add_initiator_node_acl(
305         struct se_portal_group *tpg,
306         const char *initiatorname)
307 {
308         struct se_node_acl *acl;
309
310         mutex_lock(&tpg->acl_node_mutex);
311         acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
312         if (acl) {
313                 if (acl->dynamic_node_acl) {
314                         acl->dynamic_node_acl = 0;
315                         pr_debug("%s_TPG[%u] - Replacing dynamic ACL"
316                                 " for %s\n", tpg->se_tpg_tfo->get_fabric_name(),
317                                 tpg->se_tpg_tfo->tpg_get_tag(tpg), initiatorname);
318                         mutex_unlock(&tpg->acl_node_mutex);
319                         return acl;
320                 }
321
322                 pr_err("ACL entry for %s Initiator"
323                         " Node %s already exists for TPG %u, ignoring"
324                         " request.\n",  tpg->se_tpg_tfo->get_fabric_name(),
325                         initiatorname, tpg->se_tpg_tfo->tpg_get_tag(tpg));
326                 mutex_unlock(&tpg->acl_node_mutex);
327                 return ERR_PTR(-EEXIST);
328         }
329         mutex_unlock(&tpg->acl_node_mutex);
330
331         acl = target_alloc_node_acl(tpg, initiatorname);
332         if (!acl)
333                 return ERR_PTR(-ENOMEM);
334
335         target_add_node_acl(acl);
336         return acl;
337 }
338
339 static void target_shutdown_sessions(struct se_node_acl *acl)
340 {
341         struct se_session *sess;
342         unsigned long flags;
343
344 restart:
345         spin_lock_irqsave(&acl->nacl_sess_lock, flags);
346         list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
347                 if (sess->sess_tearing_down)
348                         continue;
349
350                 list_del_init(&sess->sess_acl_list);
351                 spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
352
353                 if (acl->se_tpg->se_tpg_tfo->close_session)
354                         acl->se_tpg->se_tpg_tfo->close_session(sess);
355                 goto restart;
356         }
357         spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
358 }
359
360 void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
361 {
362         struct se_portal_group *tpg = acl->se_tpg;
363
364         mutex_lock(&tpg->acl_node_mutex);
365         if (acl->dynamic_node_acl)
366                 acl->dynamic_node_acl = 0;
367         list_del(&acl->acl_list);
368         mutex_unlock(&tpg->acl_node_mutex);
369
370         target_shutdown_sessions(acl);
371
372         target_put_nacl(acl);
373         /*
374          * Wait for last target_put_nacl() to complete in target_complete_nacl()
375          * for active fabric session transport_deregister_session() callbacks.
376          */
377         wait_for_completion(&acl->acl_free_comp);
378
379         core_tpg_wait_for_nacl_pr_ref(acl);
380         core_free_device_list_for_node(acl, tpg);
381
382         pr_debug("%s_TPG[%hu] - Deleted ACL with TCQ Depth: %d for %s"
383                 " Initiator Node: %s\n", tpg->se_tpg_tfo->get_fabric_name(),
384                 tpg->se_tpg_tfo->tpg_get_tag(tpg), acl->queue_depth,
385                 tpg->se_tpg_tfo->get_fabric_name(), acl->initiatorname);
386
387         kfree(acl);
388 }
389
390 /*      core_tpg_set_initiator_node_queue_depth():
391  *
392  *
393  */
394 int core_tpg_set_initiator_node_queue_depth(
395         struct se_node_acl *acl,
396         u32 queue_depth)
397 {
398         struct se_portal_group *tpg = acl->se_tpg;
399
400         /*
401          * User has requested to change the queue depth for a Initiator Node.
402          * Change the value in the Node's struct se_node_acl, and call
403          * target_set_nacl_queue_depth() to set the new queue depth.
404          */
405         target_set_nacl_queue_depth(tpg, acl, queue_depth);
406
407         /*
408          * Shutdown all pending sessions to force session reinstatement.
409          */
410         target_shutdown_sessions(acl);
411
412         pr_debug("Successfully changed queue depth to: %d for Initiator"
413                 " Node: %s on %s Target Portal Group: %u\n", acl->queue_depth,
414                 acl->initiatorname, tpg->se_tpg_tfo->get_fabric_name(),
415                 tpg->se_tpg_tfo->tpg_get_tag(tpg));
416
417         return 0;
418 }
419 EXPORT_SYMBOL(core_tpg_set_initiator_node_queue_depth);
420
421 /*      core_tpg_set_initiator_node_tag():
422  *
423  *      Initiator nodeacl tags are not used internally, but may be used by
424  *      userspace to emulate aliases or groups.
425  *      Returns length of newly-set tag or -EINVAL.
426  */
427 int core_tpg_set_initiator_node_tag(
428         struct se_portal_group *tpg,
429         struct se_node_acl *acl,
430         const char *new_tag)
431 {
432         if (strlen(new_tag) >= MAX_ACL_TAG_SIZE)
433                 return -EINVAL;
434
435         if (!strncmp("NULL", new_tag, 4)) {
436                 acl->acl_tag[0] = '\0';
437                 return 0;
438         }
439
440         return snprintf(acl->acl_tag, MAX_ACL_TAG_SIZE, "%s", new_tag);
441 }
442 EXPORT_SYMBOL(core_tpg_set_initiator_node_tag);
443
444 static void core_tpg_lun_ref_release(struct percpu_ref *ref)
445 {
446         struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
447
448         complete(&lun->lun_ref_comp);
449 }
450
451 /* Does not change se_wwn->priv. */
452 int core_tpg_register(
453         struct se_wwn *se_wwn,
454         struct se_portal_group *se_tpg,
455         int proto_id)
456 {
457         int ret;
458
459         if (!se_tpg)
460                 return -EINVAL;
461         /*
462          * For the typical case where core_tpg_register() is called by a
463          * fabric driver from target_core_fabric_ops->fabric_make_tpg()
464          * configfs context, use the original tf_ops pointer already saved
465          * by target-core in target_fabric_make_wwn().
466          *
467          * Otherwise, for special cases like iscsi-target discovery TPGs
468          * the caller is responsible for setting ->se_tpg_tfo ahead of
469          * calling core_tpg_register().
470          */
471         if (se_wwn)
472                 se_tpg->se_tpg_tfo = se_wwn->wwn_tf->tf_ops;
473
474         if (!se_tpg->se_tpg_tfo) {
475                 pr_err("Unable to locate se_tpg->se_tpg_tfo pointer\n");
476                 return -EINVAL;
477         }
478
479         INIT_HLIST_HEAD(&se_tpg->tpg_lun_hlist);
480         se_tpg->proto_id = proto_id;
481         se_tpg->se_tpg_wwn = se_wwn;
482         atomic_set(&se_tpg->tpg_pr_ref_count, 0);
483         INIT_LIST_HEAD(&se_tpg->acl_node_list);
484         INIT_LIST_HEAD(&se_tpg->se_tpg_node);
485         INIT_LIST_HEAD(&se_tpg->tpg_sess_list);
486         spin_lock_init(&se_tpg->session_lock);
487         mutex_init(&se_tpg->tpg_lun_mutex);
488         mutex_init(&se_tpg->acl_node_mutex);
489
490         if (se_tpg->proto_id >= 0) {
491                 se_tpg->tpg_virt_lun0 = core_tpg_alloc_lun(se_tpg, 0);
492                 if (IS_ERR(se_tpg->tpg_virt_lun0))
493                         return PTR_ERR(se_tpg->tpg_virt_lun0);
494
495                 ret = core_tpg_add_lun(se_tpg, se_tpg->tpg_virt_lun0,
496                                 true, g_lun0_dev);
497                 if (ret < 0) {
498                         kfree(se_tpg->tpg_virt_lun0);
499                         return ret;
500                 }
501         }
502
503         spin_lock_bh(&tpg_lock);
504         list_add_tail(&se_tpg->se_tpg_node, &tpg_list);
505         spin_unlock_bh(&tpg_lock);
506
507         pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
508                  "Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->get_fabric_name(),
509                 se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) ?
510                 se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) : NULL,
511                 se_tpg->proto_id, se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
512
513         return 0;
514 }
515 EXPORT_SYMBOL(core_tpg_register);
516
517 int core_tpg_deregister(struct se_portal_group *se_tpg)
518 {
519         const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
520         struct se_node_acl *nacl, *nacl_tmp;
521         LIST_HEAD(node_list);
522
523         pr_debug("TARGET_CORE[%s]: Deallocating portal_group for endpoint: %s, "
524                  "Proto: %d, Portal Tag: %u\n", tfo->get_fabric_name(),
525                 tfo->tpg_get_wwn(se_tpg) ? tfo->tpg_get_wwn(se_tpg) : NULL,
526                 se_tpg->proto_id, tfo->tpg_get_tag(se_tpg));
527
528         spin_lock_bh(&tpg_lock);
529         list_del(&se_tpg->se_tpg_node);
530         spin_unlock_bh(&tpg_lock);
531
532         while (atomic_read(&se_tpg->tpg_pr_ref_count) != 0)
533                 cpu_relax();
534
535         mutex_lock(&se_tpg->acl_node_mutex);
536         list_splice_init(&se_tpg->acl_node_list, &node_list);
537         mutex_unlock(&se_tpg->acl_node_mutex);
538         /*
539          * Release any remaining demo-mode generated se_node_acl that have
540          * not been released because of TFO->tpg_check_demo_mode_cache() == 1
541          * in transport_deregister_session().
542          */
543         list_for_each_entry_safe(nacl, nacl_tmp, &node_list, acl_list) {
544                 list_del(&nacl->acl_list);
545
546                 core_tpg_wait_for_nacl_pr_ref(nacl);
547                 core_free_device_list_for_node(nacl, se_tpg);
548                 kfree(nacl);
549         }
550
551         if (se_tpg->proto_id >= 0) {
552                 core_tpg_remove_lun(se_tpg, se_tpg->tpg_virt_lun0);
553                 kfree_rcu(se_tpg->tpg_virt_lun0, rcu_head);
554         }
555
556         return 0;
557 }
558 EXPORT_SYMBOL(core_tpg_deregister);
559
560 struct se_lun *core_tpg_alloc_lun(
561         struct se_portal_group *tpg,
562         u64 unpacked_lun)
563 {
564         struct se_lun *lun;
565
566         lun = kzalloc(sizeof(*lun), GFP_KERNEL);
567         if (!lun) {
568                 pr_err("Unable to allocate se_lun memory\n");
569                 return ERR_PTR(-ENOMEM);
570         }
571         lun->unpacked_lun = unpacked_lun;
572         lun->lun_link_magic = SE_LUN_LINK_MAGIC;
573         atomic_set(&lun->lun_acl_count, 0);
574         init_completion(&lun->lun_ref_comp);
575         INIT_LIST_HEAD(&lun->lun_deve_list);
576         INIT_LIST_HEAD(&lun->lun_dev_link);
577         atomic_set(&lun->lun_tg_pt_secondary_offline, 0);
578         spin_lock_init(&lun->lun_deve_lock);
579         mutex_init(&lun->lun_tg_pt_md_mutex);
580         INIT_LIST_HEAD(&lun->lun_tg_pt_gp_link);
581         spin_lock_init(&lun->lun_tg_pt_gp_lock);
582         lun->lun_tpg = tpg;
583
584         return lun;
585 }
586
587 int core_tpg_add_lun(
588         struct se_portal_group *tpg,
589         struct se_lun *lun,
590         bool lun_access_ro,
591         struct se_device *dev)
592 {
593         int ret;
594
595         ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release, 0,
596                               GFP_KERNEL);
597         if (ret < 0)
598                 goto out;
599
600         ret = core_alloc_rtpi(lun, dev);
601         if (ret)
602                 goto out_kill_ref;
603
604         if (!(dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH) &&
605             !(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
606                 target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp);
607
608         mutex_lock(&tpg->tpg_lun_mutex);
609
610         spin_lock(&dev->se_port_lock);
611         lun->lun_index = dev->dev_index;
612         rcu_assign_pointer(lun->lun_se_dev, dev);
613         dev->export_count++;
614         list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
615         spin_unlock(&dev->se_port_lock);
616
617         if (dev->dev_flags & DF_READ_ONLY)
618                 lun->lun_access_ro = true;
619         else
620                 lun->lun_access_ro = lun_access_ro;
621         if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
622                 hlist_add_head_rcu(&lun->link, &tpg->tpg_lun_hlist);
623         mutex_unlock(&tpg->tpg_lun_mutex);
624
625         return 0;
626
627 out_kill_ref:
628         percpu_ref_exit(&lun->lun_ref);
629 out:
630         return ret;
631 }
632
633 void core_tpg_remove_lun(
634         struct se_portal_group *tpg,
635         struct se_lun *lun)
636 {
637         /*
638          * rcu_dereference_raw protected by se_lun->lun_group symlink
639          * reference to se_device->dev_group.
640          */
641         struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);
642
643         core_clear_lun_from_tpg(lun, tpg);
644         /*
645          * Wait for any active I/O references to percpu se_lun->lun_ref to
646          * be released.  Also, se_lun->lun_ref is now used by PR and ALUA
647          * logic when referencing a remote target port during ALL_TGT_PT=1
648          * and generating UNIT_ATTENTIONs for ALUA access state transition.
649          */
650         transport_clear_lun_ref(lun);
651
652         mutex_lock(&tpg->tpg_lun_mutex);
653         if (lun->lun_se_dev) {
654                 target_detach_tg_pt_gp(lun);
655
656                 spin_lock(&dev->se_port_lock);
657                 list_del(&lun->lun_dev_link);
658                 dev->export_count--;
659                 rcu_assign_pointer(lun->lun_se_dev, NULL);
660                 spin_unlock(&dev->se_port_lock);
661         }
662         if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
663                 hlist_del_rcu(&lun->link);
664         mutex_unlock(&tpg->tpg_lun_mutex);
665
666         percpu_ref_exit(&lun->lun_ref);
667 }