aboutsummaryrefslogtreecommitdiff
path: root/drivers/scsi/scsi_transport_iscsi.c
blob: 50ed88f98f4678063243983576d64b3c158f9f82 (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
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
/*
 * iSCSI transport class definitions
 *
 * Copyright (C) IBM Corporation, 2004
 * Copyright (C) Mike Christie, 2004 - 2005
 * Copyright (C) Dmitry Yusupov, 2004 - 2005
 * Copyright (C) Alex Aizman, 2004 - 2005
 *
 * 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/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/mempool.h>
#include <linux/mutex.h>
#include <net/tcp.h>

#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/iscsi_if.h>

#define ISCSI_SESSION_ATTRS 8
#define ISCSI_CONN_ATTRS 6

struct iscsi_internal {
	struct scsi_transport_template t;
	struct iscsi_transport *iscsi_transport;
	struct list_head list;
	/*
	 * List of sessions for this transport
	 */
	struct list_head sessions;
	/*
	 * lock to serialize access to the sessions list which must
	 * be taken after the rx_queue_mutex
	 */
	spinlock_t session_lock;
	/*
	 * based on transport capabilities, at register time we set these
	 * bits to tell the transport class it wants attributes displayed
	 * in sysfs or that it can support different iSCSI Data-Path
	 * capabilities
	 */
	uint32_t param_mask;

	struct class_device cdev;
	/*
	 * We do not have any private or other attrs.
	 */
	struct transport_container conn_cont;
	struct class_device_attribute *conn_attrs[ISCSI_CONN_ATTRS + 1];
	struct transport_container session_cont;
	struct class_device_attribute *session_attrs[ISCSI_SESSION_ATTRS + 1];
};

/*
 * list of registered transports and lock that must
 * be held while accessing list. The iscsi_transport_lock must
 * be acquired after the rx_queue_mutex.
 */
static LIST_HEAD(iscsi_transports);
static DEFINE_SPINLOCK(iscsi_transport_lock);

#define to_iscsi_internal(tmpl) \
	container_of(tmpl, struct iscsi_internal, t)

#define cdev_to_iscsi_internal(_cdev) \
	container_of(_cdev, struct iscsi_internal, cdev)

static void iscsi_transport_release(struct class_device *cdev)
{
	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
	kfree(priv);
}

/*
 * iscsi_transport_class represents the iscsi_transports that are
 * registered.
 */
static struct class iscsi_transport_class = {
	.name = "iscsi_transport",
	.release = iscsi_transport_release,
};

static ssize_t
show_transport_handle(struct class_device *cdev, char *buf)
{
	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
	return sprintf(buf, "%llu\n", (unsigned long long)iscsi_handle(priv->iscsi_transport));
}
static CLASS_DEVICE_ATTR(handle, S_IRUGO, show_transport_handle, NULL);

#define show_transport_attr(name, format)				\
static ssize_t								\
show_transport_##name(struct class_device *cdev, char *buf)		\
{									\
	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);	\
	return sprintf(buf, format"\n", priv->iscsi_transport->name);	\
}									\
static CLASS_DEVICE_ATTR(name, S_IRUGO, show_transport_##name, NULL);

show_transport_attr(caps, "0x%x");
show_transport_attr(max_lun, "%d");
show_transport_attr(max_conn, "%d");
show_transport_attr(max_cmd_len, "%d");

static struct attribute *iscsi_transport_attrs[] = {
	&class_device_attr_handle.attr,
	&class_device_attr_caps.attr,
	&class_device_attr_max_lun.attr,
	&class_device_attr_max_conn.attr,
	&class_device_attr_max_cmd_len.attr,
	NULL,
};

static struct attribute_group iscsi_transport_group = {
	.attrs = iscsi_transport_attrs,
};

static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
			       "iscsi_session",
			       NULL,
			       NULL,
			       NULL);

static DECLARE_TRANSPORT_CLASS(iscsi_connection_class,
			       "iscsi_connection",
			       NULL,
			       NULL,
			       NULL);

static struct sock *nls;
static int daemon_pid;
static DEFINE_MUTEX(rx_queue_mutex);

struct mempool_zone {
	mempool_t *pool;
	atomic_t allocated;
	int size;
	int hiwat;
	struct list_head freequeue;
	spinlock_t freelock;
};

static struct mempool_zone z_reply;

/*
 * Z_MAX_* - actual mempool size allocated at the mempool_zone_init() time
 * Z_HIWAT_* - zone's high watermark when if_error bit will be set to -ENOMEM
 *             so daemon will notice OOM on NETLINK tranposrt level and will
 *             be able to predict or change operational behavior
 */
#define Z_MAX_REPLY	8
#define Z_HIWAT_REPLY	6
#define Z_MAX_PDU	8
#define Z_HIWAT_PDU	6
#define Z_MAX_ERROR	16
#define Z_HIWAT_ERROR	12

struct iscsi_if_conn {
	struct list_head conn_list;	/* item in connlist */
	struct list_head session_list;	/* item in session->connections */
	iscsi_connh_t connh;
	int active;			/* must be accessed with the connlock */
	struct Scsi_Host *host;		/* originated shost */
	struct device dev;		/* sysfs transport/container device */
	struct iscsi_transport *transport;
	struct mempool_zone z_error;
	struct mempool_zone z_pdu;
	struct list_head freequeue;
};

#define iscsi_dev_to_if_conn(_dev) \
	container_of(_dev, struct iscsi_if_conn, dev)

#define iscsi_cdev_to_if_conn(_cdev) \
	iscsi_dev_to_if_conn(_cdev->dev)

static LIST_HEAD(connlist);
static DEFINE_SPINLOCK(connlock);

struct iscsi_if_session {
	struct list_head list;	/* item in session_list */
	struct list_head connections;
	iscsi_sessionh_t sessionh;
	struct iscsi_transport *transport;
	struct device dev;	/* sysfs transport/container device */
};

#define iscsi_dev_to_if_session(_dev) \
	container_of(_dev, struct iscsi_if_session, dev)

#define iscsi_cdev_to_if_session(_cdev) \
	iscsi_dev_to_if_session(_cdev->dev)

#define iscsi_if_session_to_shost(_session) \
	dev_to_shost(_session->dev.parent)

static struct iscsi_if_conn*
iscsi_if_find_conn(uint64_t key)
{
	unsigned long flags;
	struct iscsi_if_conn *conn;

	spin_lock_irqsave(&connlock, flags);
	list_for_each_entry(conn, &connlist, conn_list)
		if (conn->connh == key) {
			spin_unlock_irqrestore(&connlock, flags);
			return conn;
		}
	spin_unlock_irqrestore(&connlock, flags);
	return NULL;
}

static struct iscsi_internal *
iscsi_if_transport_lookup(struct iscsi_transport *tt)
{
	struct iscsi_internal *priv;
	unsigned long flags;

	spin_lock_irqsave(&iscsi_transport_lock, flags);
	list_for_each_entry(priv, &iscsi_transports, list) {
		if (tt == priv->iscsi_transport) {
			spin_unlock_irqrestore(&iscsi_transport_lock, flags);
			return priv;
		}
	}
	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
	return NULL;
}

static inline struct list_head *skb_to_lh(struct sk_buff *skb)
{
	return (struct list_head *)&skb->cb;
}

static void*
mempool_zone_alloc_skb(gfp_t gfp_mask, void *pool_data)
{
	struct mempool_zone *zone = pool_data;

	return alloc_skb(zone->size, gfp_mask);
}

static void
mempool_zone_free_skb(void *element, void *pool_data)
{
	kfree_skb(element);
}

static void
mempool_zone_complete(struct mempool_zone *zone)
{
	unsigned long flags;
	struct list_head *lh, *n;

	spin_lock_irqsave(&zone->freelock, flags);
	list_for_each_safe(lh, n, &zone->freequeue) {
		struct sk_buff *skb = (struct sk_buff *)((char *)lh -
				offsetof(struct sk_buff, cb));
		if (!skb_shared(skb)) {
			list_del(skb_to_lh(skb));
			mempool_free(skb, zone->pool);
			atomic_dec(&zone->allocated);
		}
	}
	spin_unlock_irqrestore(&zone->freelock, flags);
}

static int
mempool_zone_init(struct mempool_zone *zp, unsigned max, unsigned size,
		unsigned hiwat)
{
	zp->pool = mempool_create(max, mempool_zone_alloc_skb,
				  mempool_zone_free_skb, zp);
	if (!zp->pool)
		return -ENOMEM;

	zp->size = size;
	zp->hiwat = hiwat;

	INIT_LIST_HEAD(&zp->freequeue);
	spin_lock_init(&zp->freelock);
	atomic_set(&zp->allocated, 0);

	return 0;
}


static struct sk_buff*
mempool_zone_get_skb(struct mempool_zone *zone)
{
	struct sk_buff *skb;

	skb = mempool_alloc(zone->pool, GFP_ATOMIC);
	if (skb)
		atomic_inc(&zone->allocated);
	return skb;
}

static int
iscsi_unicast_skb(struct mempool_zone *zone, struct sk_buff *skb)
{
	unsigned long flags;
	int rc;

	skb_get(skb);
	rc = netlink_unicast(nls, skb, daemon_pid, MSG_DONTWAIT);
	if (rc < 0) {
		mempool_free(skb, zone->pool);
		printk(KERN_ERR "iscsi: can not unicast skb (%d)\n", rc);
		return rc;
	}

	spin_lock_irqsave(&zone->freelock, flags);
	list_add(skb_to_lh(skb), &zone->freequeue);
	spin_unlock_irqrestore(&zone->freelock, flags);

	return 0;
}

int iscsi_recv_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr,
		   char *data, uint32_t data_size)
{
	struct nlmsghdr	*nlh;
	struct sk_buff *skb;
	struct iscsi_uevent *ev;
	struct iscsi_if_conn *conn;
	char *pdu;
	int len = NLMSG_SPACE(sizeof(*ev) + sizeof(struct iscsi_hdr) +
			      data_size);

	conn = iscsi_if_find_conn(connh);
	BUG_ON(!conn);

	mempool_zone_complete(&conn->z_pdu);

	skb = mempool_zone_get_skb(&conn->z_pdu);
	if (!skb) {
		iscsi_conn_error(connh, ISCSI_ERR_CONN_FAILED);
		printk(KERN_ERR "iscsi%d: can not deliver control PDU: OOM\n",
		       conn->host->host_no);
		return -ENOMEM;
	}

	nlh = __nlmsg_put(skb, daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
	ev = NLMSG_DATA(nlh);
	memset(ev, 0, sizeof(*ev));
	ev->transport_handle = iscsi_handle(conn->transport);
	ev->type = ISCSI_KEVENT_RECV_PDU;
	if (atomic_read(&conn->z_pdu.allocated) >= conn->z_pdu.hiwat)
		ev->iferror = -ENOMEM;
	ev->r.recv_req.conn_handle = connh;
	pdu = (char*)ev + sizeof(*ev);
	memcpy(pdu, hdr, sizeof(struct iscsi_hdr));
	memcpy(pdu + sizeof(struct iscsi_hdr), data, data_size);

	return iscsi_unicast_skb(&conn->z_pdu, skb);
}
EXPORT_SYMBOL_GPL(iscsi_recv_pdu);

void iscsi_conn_error(iscsi_connh_t connh, enum iscsi_err error)
{
	struct nlmsghdr	*nlh;
	struct sk_buff	*skb;
	struct iscsi_uevent *ev;
	struct iscsi_if_conn *conn;
	int len = NLMSG_SPACE(sizeof(*ev));

	conn = iscsi_if_find_conn(connh);
	BUG_ON(!conn);

	mempool_zone_complete(&conn->z_error);

	skb = mempool_zone_get_skb(&conn->z_error);
	if (!skb) {
		printk(KERN_ERR "iscsi%d: gracefully ignored conn error (%d)\n",
		       conn->host->host_no, error);
		return;
	}

	nlh = __nlmsg_put(skb, daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
	ev = NLMSG_DATA(nlh);
	ev->transport_handle = iscsi_handle(conn->transport);
	ev->type = ISCSI_KEVENT_CONN_ERROR;
	if (atomic_read(&conn->z_error.allocated) >= conn->z_error.hiwat)
		ev->iferror = -ENOMEM;
	ev->r.connerror.error = error;
	ev->r.connerror.conn_handle = connh;

	iscsi_unicast_skb(&conn->z_error, skb);

	printk(KERN_INFO "iscsi%d: detected conn error (%d)\n",
	       conn->host->host_no, error);
}
EXPORT_SYMBOL_GPL(iscsi_conn_error);

static int
iscsi_if_send_reply(int pid, int seq, int type, int done, int multi,
		      void *payload, int size)
{
	struct sk_buff	*skb;
	struct nlmsghdr	*nlh;
	int len = NLMSG_SPACE(size);
	int flags = multi ? NLM_F_MULTI : 0;
	int t = done ? NLMSG_DONE : type;

	mempool_zone_complete(&z_reply);

	skb = mempool_zone_get_skb(&z_reply);
	/*
	 * FIXME:
	 * user is supposed to react on iferror == -ENOMEM;
	 * see iscsi_if_rx().
	 */
	BUG_ON(!skb);

	nlh = __nlmsg_put(skb, pid, seq, t, (len - sizeof(*nlh)), 0);
	nlh->nlmsg_flags = flags;
	memcpy(NLMSG_DATA(nlh), payload, size);
	return iscsi_unicast_skb(&z_reply, skb);
}

/*
 * iSCSI Session's hostdata organization:
 *
 *    *------------------* <== host->hostdata
 *    | transport        |
 *    |------------------| <== iscsi_hostdata(host->hostdata)
 *    | transport's data |
 *    |------------------| <== hostdata_session(host->hostdata)
 *    | interface's data |
 *    *------------------*
 */

#define hostdata_privsize(_t)	(sizeof(unsigned long) + _t->hostdata_size + \
				 _t->hostdata_size % sizeof(unsigned long) + \
				 sizeof(struct iscsi_if_session))

#define hostdata_session(_hostdata) ((void*)_hostdata + sizeof(unsigned long) + \
			((struct iscsi_transport *) \
			 iscsi_ptr(*(uint64_t *)_hostdata))->hostdata_size)

static void iscsi_if_session_dev_release(struct device *dev)
{
	struct iscsi_if_session *session = iscsi_dev_to_if_session(dev);
	struct iscsi_transport *transport = session->transport;
	struct Scsi_Host *shost = iscsi_if_session_to_shost(session);
	struct iscsi_if_conn *conn, *tmp;
	unsigned long flags;

	/* now free connections */
	spin_lock_irqsave(&connlock, flags);
	list_for_each_entry_safe(conn, tmp, &session->connections,
				 session_list) {
		list_del(&conn->session_list);
		mempool_destroy(conn->z_pdu.pool);
		mempool_destroy(conn->z_error.pool);
		kfree(conn);
	}
	spin_unlock_irqrestore(&connlock, flags);
	scsi_host_put(shost);
	module_put(transport->owner);
}

static int
iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
{
	struct iscsi_transport *transport = priv->iscsi_transport;
	struct iscsi_if_session *session;
	struct Scsi_Host *shost;
	unsigned long flags;
	int error;

	if (!try_module_get(transport->owner))
		return -EPERM;

	shost = scsi_host_alloc(transport->host_template,
				hostdata_privsize(transport));
	if (!shost) {
		ev->r.c_session_ret.session_handle = iscsi_handle(NULL);
		printk(KERN_ERR "iscsi: can not allocate SCSI host for "
		       "session\n");
		error = -ENOMEM;
		goto out_module_put;
	}
	shost->max_id = 1;
	shost->max_channel = 0;
	shost->max_lun = transport->max_lun;
	shost->max_cmd_len = transport->max_cmd_len;
	shost->transportt = &priv->t;

	/* store struct iscsi_transport in hostdata */
	*(uint64_t*)shost->hostdata = ev->transport_handle;

	ev->r.c_session_ret.session_handle = transport->create_session(
					ev->u.c_session.initial_cmdsn, shost);
	if (ev->r.c_session_ret.session_handle == iscsi_handle(NULL)) {
		error = 0;
		goto out_host_put;
	}

	/* host_no becomes assigned SID */
	ev->r.c_session_ret.sid = shost->host_no;
	/* initialize session */
	session = hostdata_session(shost->hostdata);
	INIT_LIST_HEAD(&session->connections);
	INIT_LIST_HEAD(&session->list);
	session->sessionh = ev->r.c_session_ret.session_handle;
	session->transport = transport;

	error = scsi_add_host(shost, NULL);
	if (error)
		goto out_destroy_session;

	/*
	 * this is released in the dev's release function)
	 */
	scsi_host_get(shost);
	snprintf(session->dev.bus_id, BUS_ID_SIZE, "session%u", shost->host_no);
	session->dev.parent = &shost->shost_gendev;
	session->dev.release = iscsi_if_session_dev_release;
	error = device_register(&session->dev);
	if (error) {
		printk(KERN_ERR "iscsi: could not register session%d's dev\n",
		       shost->host_no);
		goto out_remove_host;
	}
	transport_register_device(&session->dev);

	/* add this session to the list of active sessions */
	spin_lock_irqsave(&priv->session_lock, flags);
	list_add(&session->list, &priv->sessions);
	spin_unlock_irqrestore(&priv->session_lock, flags);

	return 0;

out_remove_host:
	scsi_remove_host(shost);
out_destroy_session:
	transport->destroy_session(ev->r.c_session_ret.session_handle);
	ev->r.c_session_ret.session_handle = iscsi_handle(NULL);
out_host_put:
	scsi_host_put(shost);
out_module_put:
	module_put(transport->owner);
	return error;
}

static int
iscsi_if_destroy_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
{
	struct iscsi_transport *transport = priv->iscsi_transport;
	struct Scsi_Host *shost;
	struct iscsi_if_session *session;
	unsigned long flags;
	struct iscsi_if_conn *conn;
	int error = 0;

	shost = scsi_host_lookup(ev->u.d_session.sid);
	if (shost == ERR_PTR(-ENXIO))
		return -EEXIST;
	session = hostdata_session(shost->hostdata);

	/* check if we have active connections */
	spin_lock_irqsave(&connlock, flags);
	list_for_each_entry(conn, &session->connections, session_list) {
		if (conn->active) {
			printk(KERN_ERR "iscsi%d: can not destroy session: "
			       "has active connection (%p)\n",
			       shost->host_no, iscsi_ptr(conn->connh));
			spin_unlock_irqrestore(&connlock, flags);
			error = EIO;
			goto out_release_ref;
		}
	}
	spin_unlock_irqrestore(&connlock, flags);

	scsi_remove_host(shost);
	transport->destroy_session(ev->u.d_session.session_handle);
	transport_unregister_device(&session->dev);
	device_unregister(&session->dev);

	/* remove this session from the list of active sessions */
	spin_lock_irqsave(&priv->session_lock, flags);
	list_del(&session->list);
	spin_unlock_irqrestore(&priv->session_lock, flags);

	/* ref from host alloc */
	scsi_host_put(shost);
out_release_ref:
	/* ref from host lookup */
	scsi_host_put(shost);
	return error;
}

static void iscsi_if_conn_dev_release(struct device *dev)
{
	struct iscsi_if_conn *conn = iscsi_dev_to_if_conn(dev);
	struct Scsi_Host *shost = conn->host;

	scsi_host_put(shost);
}

static int
iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
{
	struct iscsi_if_session *session;
	struct Scsi_Host *shost;
	struct iscsi_if_conn *conn;
	unsigned long flags;
	int error;

	shost = scsi_host_lookup(ev->u.c_conn.sid);
	if (shost == ERR_PTR(-ENXIO))
		return -EEXIST;
	session = hostdata_session(shost->hostdata);

	conn = kmalloc(sizeof(struct iscsi_if_conn), GFP_KERNEL);
	if (!conn) {
		error = -ENOMEM;
		goto out_release_ref;
	}
	memset(conn, 0, sizeof(struct iscsi_if_conn));
	INIT_LIST_HEAD(&conn->session_list);
	INIT_LIST_HEAD(&conn->conn_list);
	conn->host = shost;
	conn->transport = transport;

	error = mempool_zone_init(&conn->z_pdu, Z_MAX_PDU,
			NLMSG_SPACE(sizeof(struct iscsi_uevent) +
				    sizeof(struct iscsi_hdr) +
				    DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH),
			Z_HIWAT_PDU);
	if (error) {
		printk(KERN_ERR "iscsi%d: can not allocate pdu zone for new "
		       "conn\n", shost->host_no);
		goto out_free_conn;
	}
	error = mempool_zone_init(&conn->z_error, Z_MAX_ERROR,
			NLMSG_SPACE(sizeof(struct iscsi_uevent)),
			Z_HIWAT_ERROR);
	if (error) {
		printk(KERN_ERR "iscsi%d: can not allocate error zone for "
		       "new conn\n", shost->host_no);
		goto out_free_pdu_pool;
	}

	ev->r.handle = transport->create_conn(ev->u.c_conn.session_handle,
					ev->u.c_conn.cid);
	if (!ev->r.handle) {
		error = -ENODEV;
		goto out_free_error_pool;
	}

	conn->connh = ev->r.handle;

	/*
	 * this is released in the dev's release function
	 */
	if (!scsi_host_get(shost))
		goto out_destroy_conn;
	snprintf(conn->dev.bus_id, BUS_ID_SIZE, "connection%d:%u",
		 shost->host_no, ev->u.c_conn.cid);
	conn->dev.parent = &session->dev;
	conn->dev.release = iscsi_if_conn_dev_release;
	error = device_register(&conn->dev);
	if (error) {
		printk(KERN_ERR "iscsi%d: could not register connections%u "
		       "dev\n", shost->host_no, ev->u.c_conn.cid);
		goto out_release_parent_ref;
	}
	transport_register_device(&conn->dev);

	spin_lock_irqsave(&connlock, flags);
	list_add(&conn->conn_list, &connlist);
	list_add(&conn->session_list, &session->connections);
	conn->active = 1;
	spin_unlock_irqrestore(&connlock, flags);

	scsi_host_put(shost);
	return 0;

out_release_parent_ref:
	scsi_host_put(shost);
out_destroy_conn:
	transport->destroy_conn(ev->r.handle);
out_free_error_pool:
	mempool_destroy(conn->z_error.pool);
out_free_pdu_pool:
	mempool_destroy(conn->z_pdu.pool);
out_free_conn:
	kfree(conn);
out_release_ref:
	scsi_host_put(shost);
	return error;
}

static int
iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
{
	unsigned long flags;
	struct iscsi_if_conn *conn;

	conn = iscsi_if_find_conn(ev->u.d_conn.conn_handle);
	if (!conn)
		return -EEXIST;

	transport->destroy_conn(ev->u.d_conn.conn_handle);

	spin_lock_irqsave(&connlock, flags);
	conn->active = 0;
	list_del(&conn->conn_list);
	spin_unlock_irqrestore(&connlock, flags);

	transport_unregister_device(&conn->dev);
	device_unregister(&conn->dev);
	return 0;
}

static int
iscsi_if_get_stats(struct iscsi_transport *transport, struct sk_buff *skb,
		   struct nlmsghdr *nlh)
{
	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
	struct iscsi_stats *stats;
	struct sk_buff *skbstat;
	struct iscsi_if_conn *conn;
	struct nlmsghdr	*nlhstat;
	struct iscsi_uevent *evstat;
	int len = NLMSG_SPACE(sizeof(*ev) +
			      sizeof(struct iscsi_stats) +
			      sizeof(struct iscsi_stats_custom) *
			      ISCSI_STATS_CUSTOM_MAX);
	int err = 0;

	conn = iscsi_if_find_conn(ev->u.get_stats.conn_handle);
	if (!conn)
		return -EEXIST;

	do {
		int actual_size;

		mempool_zone_complete(&conn->z_pdu);

		skbstat = mempool_zone_get_skb(&conn->z_pdu);
		if (!skbstat) {
			printk(KERN_ERR "iscsi%d: can not deliver stats: OOM\n",
			       conn->host->host_no);
			return -ENOMEM;
		}

		nlhstat = __nlmsg_put(skbstat, daemon_pid, 0, 0,
				      (len - sizeof(*nlhstat)), 0);
		evstat = NLMSG_DATA(nlhstat);
		memset(evstat, 0, sizeof(*evstat));
		evstat->transport_handle = iscsi_handle(conn->transport);
		evstat->type = nlh->nlmsg_type;
		if (atomic_read(&conn->z_pdu.allocated) >= conn->z_pdu.hiwat)
			evstat->iferror = -ENOMEM;
		evstat->u.get_stats.conn_handle =
			ev->u.get_stats.conn_handle;
		stats = (struct iscsi_stats *)
			((char*)evstat + sizeof(*evstat));
		memset(stats, 0, sizeof(*stats));

		transport->get_stats(ev->u.get_stats.conn_handle, stats);
		actual_size = NLMSG_SPACE(sizeof(struct iscsi_uevent) +
					  sizeof(struct iscsi_stats) +
					  sizeof(struct iscsi_stats_custom) *
					  stats->custom_length);
		actual_size -= sizeof(*nlhstat);
		actual_size = NLMSG_LENGTH(actual_size);
		skb_trim(skb, NLMSG_ALIGN(actual_size));
		nlhstat->nlmsg_len = actual_size;

		err = iscsi_unicast_skb(&conn->z_pdu, skbstat);
	} while (err < 0 && err != -ECONNREFUSED);

	return err;
}

static int
iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	int err = 0;
	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
	struct iscsi_transport *transport = NULL;
	struct iscsi_internal *priv;

	if (NETLINK_CREDS(skb)->uid)
		return -EPERM;

	priv = iscsi_if_transport_lookup(iscsi_ptr(ev->transport_handle));
	if (!priv)
		return -EINVAL;
	transport = priv->iscsi_transport;

	daemon_pid = NETLINK_CREDS(skb)->pid;

	switch (nlh->nlmsg_type) {
	case ISCSI_UEVENT_CREATE_SESSION:
		err = iscsi_if_create_session(priv, ev);
		break;
	case ISCSI_UEVENT_DESTROY_SESSION:
		err = iscsi_if_destroy_session(priv, ev);
		break;
	case ISCSI_UEVENT_CREATE_CONN:
		err = iscsi_if_create_conn(transport, ev);
		break;
	case ISCSI_UEVENT_DESTROY_CONN:
		err = iscsi_if_destroy_conn(transport, ev);
		break;
	case ISCSI_UEVENT_BIND_CONN:
		if (!iscsi_if_find_conn(ev->u.b_conn.conn_handle))
			return -EEXIST;
		ev->r.retcode = transport->bind_conn(
			ev->u.b_conn.session_handle,
			ev->u.b_conn.conn_handle,
			ev->u.b_conn.transport_fd,
			ev->u.b_conn.is_leading);
		break;
	case ISCSI_UEVENT_SET_PARAM:
		if (!iscsi_if_find_conn(ev->u.set_param.conn_handle))
			return -EEXIST;
		ev->r.retcode = transport->set_param(
			ev->u.set_param.conn_handle,
			ev->u.set_param.param, ev->u.set_param.value);
		break;
	case ISCSI_UEVENT_START_CONN:
		if (!iscsi_if_find_conn(ev->u.start_conn.conn_handle))
			return -EEXIST;
		ev->r.retcode = transport->start_conn(
			ev->u.start_conn.conn_handle);
		break;
	case ISCSI_UEVENT_STOP_CONN:
		if (!iscsi_if_find_conn(ev->u.stop_conn.conn_handle))
			return -EEXIST;
		transport->stop_conn(ev->u.stop_conn.conn_handle,
			ev->u.stop_conn.flag);
		break;
	case ISCSI_UEVENT_SEND_PDU:
		if (!iscsi_if_find_conn(ev->u.send_pdu.conn_handle))
			return -EEXIST;
		ev->r.retcode = transport->send_pdu(
		       ev->u.send_pdu.conn_handle,
		       (struct iscsi_hdr*)((char*)ev + sizeof(*ev)),
		       (char*)ev + sizeof(*ev) + ev->u.send_pdu.hdr_size,
			ev->u.send_pdu.data_size);
		break;
	case ISCSI_UEVENT_GET_STATS:
		err = iscsi_if_get_stats(transport, skb, nlh);
		break;
	default:
		err = -EINVAL;
		break;
	}

	return err;
}

/* Get message from skb (based on rtnetlink_rcv_skb).  Each message is
 * processed by iscsi_if_recv_msg.  Malformed skbs with wrong length are
 * discarded silently.  */
static void
iscsi_if_rx(struct sock *sk, int len)
{
	struct sk_buff *skb;

	mutex_lock(&rx_queue_mutex);
	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
		while (skb->len >= NLMSG_SPACE(0)) {
			int err;
			uint32_t rlen;
			struct nlmsghdr	*nlh;
			struct iscsi_uevent *ev;

			nlh = (struct nlmsghdr *)skb->data;
			if (nlh->nlmsg_len < sizeof(*nlh) ||
			    skb->len < nlh->nlmsg_len) {
				break;
			}
			ev = NLMSG_DATA(nlh);
			rlen = NLMSG_ALIGN(nlh->nlmsg_len);
			if (rlen > skb->len)
				rlen = skb->len;
			err = iscsi_if_recv_msg(skb, nlh);
			if (err) {
				ev->type = ISCSI_KEVENT_IF_ERROR;
				ev->iferror = err;
			}
			do {
				/*
				 * special case for GET_STATS:
				 * on success - sending reply and stats from
				 * inside of if_recv_msg(),
				 * on error - fall through.
				 */
				if (ev->type == ISCSI_UEVENT_GET_STATS && !err)
					break;
				err = iscsi_if_send_reply(
					NETLINK_CREDS(skb)->pid, nlh->nlmsg_seq,
					nlh->nlmsg_type, 0, 0, ev, sizeof(*ev));
				if (atomic_read(&z_reply.allocated) >=
						z_reply.hiwat)
					ev->iferror = -ENOMEM;
			} while (err < 0 && err != -ECONNREFUSED);
			skb_pull(skb, rlen);
		}
		kfree_skb(skb);
	}
	mutex_unlock(&rx_queue_mutex);
}

/*
 * iSCSI connection attrs
 */
#define iscsi_conn_int_attr_show(param, format)				\
static ssize_t								\
show_conn_int_param_##param(struct class_device *cdev, char *buf)	\
{									\
	uint32_t value = 0;						\
	struct iscsi_if_conn *conn = iscsi_cdev_to_if_conn(cdev);	\
	struct iscsi_internal *priv;					\
									\
	priv = to_iscsi_internal(conn->host->transportt);		\
	if (priv->param_mask & (1 << param))				\
		priv->iscsi_transport->get_param(conn->connh, param, &value); \
	return snprintf(buf, 20, format"\n", value);			\
}

#define iscsi_conn_int_attr(field, param, format)			\
	iscsi_conn_int_attr_show(param, format)				\
static CLASS_DEVICE_ATTR(field, S_IRUGO, show_conn_int_param_##param, NULL);

iscsi_conn_int_attr(max_recv_dlength, ISCSI_PARAM_MAX_RECV_DLENGTH, "%u");
iscsi_conn_int_attr(max_xmit_dlength, ISCSI_PARAM_MAX_XMIT_DLENGTH, "%u");
iscsi_conn_int_attr(header_digest, ISCSI_PARAM_HDRDGST_EN, "%d");
iscsi_conn_int_attr(data_digest, ISCSI_PARAM_DATADGST_EN, "%d");
iscsi_conn_int_attr(ifmarker, ISCSI_PARAM_IFMARKER_EN, "%d");
iscsi_conn_int_attr(ofmarker, ISCSI_PARAM_OFMARKER_EN, "%d");

/*
 * iSCSI session attrs
 */
#define iscsi_session_int_attr_show(param, format)			\
static ssize_t								\
show_session_int_param_##param(struct class_device *cdev, char *buf)	\
{									\
	uint32_t value = 0;						\
	struct iscsi_if_session *session = iscsi_cdev_to_if_session(cdev); \
	struct Scsi_Host *shost = iscsi_if_session_to_shost(session);	\
	struct iscsi_internal *priv = to_iscsi_internal(shost->transportt); \
	struct iscsi_if_conn *conn = NULL;				\
	unsigned long  flags;						\
									\
	spin_lock_irqsave(&connlock, flags);				\
	if (!list_empty(&session->connections))				\
		conn = list_entry(session->connections.next,		\
				  struct iscsi_if_conn, session_list);	\
	spin_unlock_irqrestore(&connlock, flags);			\
									\
	if (conn && (priv->param_mask & (1 << param)))			\
		priv->iscsi_transport->get_param(conn->connh, param, &value);\
	return snprintf(buf, 20, format"\n", value);			\
}

#define iscsi_session_int_attr(field, param, format)			\
	iscsi_session_int_attr_show(param, format)			\
static CLASS_DEVICE_ATTR(field, S_IRUGO, show_session_int_param_##param, NULL);

iscsi_session_int_attr(initial_r2t, ISCSI_PARAM_INITIAL_R2T_EN, "%d");
iscsi_session_int_attr(max_outstanding_r2t, ISCSI_PARAM_MAX_R2T, "%hu");
iscsi_session_int_attr(immediate_data, ISCSI_PARAM_IMM_DATA_EN, "%d");
iscsi_session_int_attr(first_burst_len, ISCSI_PARAM_FIRST_BURST, "%u");
iscsi_session_int_attr(max_burst_len, ISCSI_PARAM_MAX_BURST, "%u");
iscsi_session_int_attr(data_pdu_in_order, ISCSI_PARAM_PDU_INORDER_EN, "%d");
iscsi_session_int_attr(data_seq_in_order, ISCSI_PARAM_DATASEQ_INORDER_EN, "%d");
iscsi_session_int_attr(erl, ISCSI_PARAM_ERL, "%d");

#define SETUP_SESSION_RD_ATTR(field, param)				\
	if (priv->param_mask & (1 << param)) {				\
		priv->session_attrs[count] = &class_device_attr_##field;\
		count++;						\
	}

#define SETUP_CONN_RD_ATTR(field, param)				\
	if (priv->param_mask & (1 << param)) {				\
		priv->conn_attrs[count] = &class_device_attr_##field;	\
		count++;						\
	}

static int iscsi_is_session_dev(const struct device *dev)
{
	return dev->release == iscsi_if_session_dev_release;
}

static int iscsi_session_match(struct attribute_container *cont,
			   struct device *dev)
{
	struct iscsi_if_session *session;
	struct Scsi_Host *shost;
	struct iscsi_internal *priv;

	if (!iscsi_is_session_dev(dev))
		return 0;

	session = iscsi_dev_to_if_session(dev);
	shost = iscsi_if_session_to_shost(session);
	if (!shost->transportt)
		return 0;

	priv = to_iscsi_internal(shost->transportt);
	if (priv->session_cont.ac.class != &iscsi_session_class.class)
		return 0;

	return &priv->session_cont.ac == cont;
}

static int iscsi_is_conn_dev(const struct device *dev)
{
	return dev->release == iscsi_if_conn_dev_release;
}

static int iscsi_conn_match(struct attribute_container *cont,
			   struct device *dev)
{
	struct iscsi_if_conn *conn;
	struct Scsi_Host *shost;
	struct iscsi_internal *priv;

	if (!iscsi_is_conn_dev(dev))
		return 0;

	conn = iscsi_dev_to_if_conn(dev);
	shost = conn->host;
	if (!shost->transportt)
		return 0;

	priv = to_iscsi_internal(shost->transportt);
	if (priv->conn_cont.ac.class != &iscsi_connection_class.class)
		return 0;

	return &priv->conn_cont.ac == cont;
}

int iscsi_register_transport(struct iscsi_transport *tt)
{
	struct iscsi_internal *priv;
	unsigned long flags;
	int count = 0, err;

	BUG_ON(!tt);

	priv = iscsi_if_transport_lookup(tt);
	if (priv)
		return -EEXIST;

	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;
	memset(priv, 0, sizeof(*priv));
	INIT_LIST_HEAD(&priv->list);
	INIT_LIST_HEAD(&priv->sessions);
	spin_lock_init(&priv->session_lock);
	priv->iscsi_transport = tt;

	priv->cdev.class = &iscsi_transport_class;
	snprintf(priv->cdev.class_id, BUS_ID_SIZE, "%s", tt->name);
	err = class_device_register(&priv->cdev);
	if (err)
		goto free_priv;

	err = sysfs_create_group(&priv->cdev.kobj, &iscsi_transport_group);
	if (err)
		goto unregister_cdev;

	/* setup parameters mask */
	priv->param_mask = 0xFFFFFFFF;
	if (!(tt->caps & CAP_MULTI_R2T))
		priv->param_mask &= ~(1 << ISCSI_PARAM_MAX_R2T);
	if (!(tt->caps & CAP_HDRDGST))
		priv->param_mask &= ~(1 << ISCSI_PARAM_HDRDGST_EN);
	if (!(tt->caps & CAP_DATADGST))
		priv->param_mask &= ~(1 << ISCSI_PARAM_DATADGST_EN);
	if (!(tt->caps & CAP_MARKERS)) {
		priv->param_mask &= ~(1 << ISCSI_PARAM_IFMARKER_EN);
		priv->param_mask &= ~(1 << ISCSI_PARAM_OFMARKER_EN);
	}

	/* connection parameters */
	priv->conn_cont.ac.attrs = &priv->conn_attrs[0];
	priv->conn_cont.ac.class = &iscsi_connection_class.class;
	priv->conn_cont.ac.match = iscsi_conn_match;
	transport_container_register(&priv->conn_cont);

	SETUP_CONN_RD_ATTR(max_recv_dlength, ISCSI_PARAM_MAX_RECV_DLENGTH);
	SETUP_CONN_RD_ATTR(max_xmit_dlength, ISCSI_PARAM_MAX_XMIT_DLENGTH);
	SETUP_CONN_RD_ATTR(header_digest, ISCSI_PARAM_HDRDGST_EN);
	SETUP_CONN_RD_ATTR(data_digest, ISCSI_PARAM_DATADGST_EN);
	SETUP_CONN_RD_ATTR(ifmarker, ISCSI_PARAM_IFMARKER_EN);
	SETUP_CONN_RD_ATTR(ofmarker, ISCSI_PARAM_OFMARKER_EN);

	BUG_ON(count > ISCSI_CONN_ATTRS);
	priv->conn_attrs[count] = NULL;
	count = 0;

	/* session parameters */
	priv->session_cont.ac.attrs = &priv->session_attrs[0];
	priv->session_cont.ac.class = &iscsi_session_class.class;
	priv->session_cont.ac.match = iscsi_session_match;
	transport_container_register(&priv->session_cont);

	SETUP_SESSION_RD_ATTR(initial_r2t, ISCSI_PARAM_INITIAL_R2T_EN);
	SETUP_SESSION_RD_ATTR(max_outstanding_r2t, ISCSI_PARAM_MAX_R2T);
	SETUP_SESSION_RD_ATTR(immediate_data, ISCSI_PARAM_IMM_DATA_EN);
	SETUP_SESSION_RD_ATTR(first_burst_len, ISCSI_PARAM_FIRST_BURST);
	SETUP_SESSION_RD_ATTR(max_burst_len, ISCSI_PARAM_MAX_BURST);
	SETUP_SESSION_RD_ATTR(data_pdu_in_order, ISCSI_PARAM_PDU_INORDER_EN);
	SETUP_SESSION_RD_ATTR(data_seq_in_order,ISCSI_PARAM_DATASEQ_INORDER_EN)
	SETUP_SESSION_RD_ATTR(erl, ISCSI_PARAM_ERL);

	BUG_ON(count > ISCSI_SESSION_ATTRS);
	priv->session_attrs[count] = NULL;

	spin_lock_irqsave(&iscsi_transport_lock, flags);
	list_add(&priv->list, &iscsi_transports);
	spin_unlock_irqrestore(&iscsi_transport_lock, flags);

	printk(KERN_NOTICE "iscsi: registered transport (%s)\n", tt->name);
	return 0;

unregister_cdev:
	class_device_unregister(&priv->cdev);
free_priv:
	kfree(priv);
	return err;
}
EXPORT_SYMBOL_GPL(iscsi_register_transport);

int iscsi_unregister_transport(struct iscsi_transport *tt)
{
	struct iscsi_internal *priv;
	unsigned long flags;

	BUG_ON(!tt);

	mutex_lock(&rx_queue_mutex);

	priv = iscsi_if_transport_lookup(tt);
	BUG_ON (!priv);

	spin_lock_irqsave(&priv->session_lock, flags);
	if (!list_empty(&priv->sessions)) {
		spin_unlock_irqrestore(&priv->session_lock, flags);
		mutex_unlock(&rx_queue_mutex);
		return -EPERM;
	}
	spin_unlock_irqrestore(&priv->session_lock, flags);

	spin_lock_irqsave(&iscsi_transport_lock, flags);
	list_del(&priv->list);
	spin_unlock_irqrestore(&iscsi_transport_lock, flags);

	transport_container_unregister(&priv->conn_cont);
	transport_container_unregister(&priv->session_cont);

	sysfs_remove_group(&priv->cdev.kobj, &iscsi_transport_group);
	class_device_unregister(&priv->cdev);
	mutex_unlock(&rx_queue_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(iscsi_unregister_transport);

static int
iscsi_rcv_nl_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct netlink_notify *n = ptr;

	if (event == NETLINK_URELEASE &&
	    n->protocol == NETLINK_ISCSI && n->pid) {
		struct iscsi_if_conn *conn;
		unsigned long flags;

		mempool_zone_complete(&z_reply);
		spin_lock_irqsave(&connlock, flags);
		list_for_each_entry(conn, &connlist, conn_list) {
			mempool_zone_complete(&conn->z_error);
			mempool_zone_complete(&conn->z_pdu);
		}
		spin_unlock_irqrestore(&connlock, flags);
	}

	return NOTIFY_DONE;
}

static struct notifier_block iscsi_nl_notifier = {
	.notifier_call	= iscsi_rcv_nl_event,
};

static __init int iscsi_transport_init(void)
{
	int err;

	err = class_register(&iscsi_transport_class);
	if (err)
		return err;

	err = transport_class_register(&iscsi_connection_class);
	if (err)
		goto unregister_transport_class;

	err = transport_class_register(&iscsi_session_class);
	if (err)
		goto unregister_conn_class;

	err = netlink_register_notifier(&iscsi_nl_notifier);
	if (err)
		goto unregister_session_class;

	nls = netlink_kernel_create(NETLINK_ISCSI, 1, iscsi_if_rx,
				    THIS_MODULE);
	if (!nls) {
		err = -ENOBUFS;
		goto unregister_notifier;
	}

	err = mempool_zone_init(&z_reply, Z_MAX_REPLY,
		NLMSG_SPACE(sizeof(struct iscsi_uevent)), Z_HIWAT_REPLY);
	if (!err)
		return 0;

	sock_release(nls->sk_socket);
unregister_notifier:
	netlink_unregister_notifier(&iscsi_nl_notifier);
unregister_session_class:
	transport_class_unregister(&iscsi_session_class);
unregister_conn_class:
	transport_class_unregister(&iscsi_connection_class);
unregister_transport_class:
	class_unregister(&iscsi_transport_class);
	return err;
}

static void __exit iscsi_transport_exit(void)
{
	mempool_destroy(z_reply.pool);
	sock_release(nls->sk_socket);
	netlink_unregister_notifier(&iscsi_nl_notifier);
	transport_class_unregister(&iscsi_connection_class);
	transport_class_unregister(&iscsi_session_class);
	class_unregister(&iscsi_transport_class);
}

module_init(iscsi_transport_init);
module_exit(iscsi_transport_exit);

MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
	      "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
	      "Alex Aizman <itn780@yahoo.com>");
MODULE_DESCRIPTION("iSCSI Transport Interface");
MODULE_LICENSE("GPL");