summaryrefslogtreecommitdiffstats
path: root/drivers/target/iscsi/iscsi_target_util.c
blob: 5041a9c8bdcbfd9bf9eb9368e850bdb8792a6be9 (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
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
/*******************************************************************************
 * This file contains the iSCSI Target specific utility functions.
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.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.
 ******************************************************************************/

#include <linux/list.h>
#include <linux/percpu_ida.h>
#include <net/ipv6.h>         /* ipv6_addr_equal() */
#include <scsi/scsi_tcq.h>
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/iscsi/iscsi_transport.h>

#include <target/iscsi/iscsi_target_core.h>
#include "iscsi_target_parameters.h"
#include "iscsi_target_seq_pdu_list.h"
#include "iscsi_target_datain_values.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target_tpg.h"
#include "iscsi_target_util.h"
#include "iscsi_target.h"

#define PRINT_BUFF(buff, len)					\
{								\
	int zzz;						\
								\
	pr_debug("%d:\n", __LINE__);				\
	for (zzz = 0; zzz < len; zzz++) {			\
		if (zzz % 16 == 0) {				\
			if (zzz)				\
				pr_debug("\n");			\
			pr_debug("%4i: ", zzz);			\
		}						\
		pr_debug("%02x ", (unsigned char) (buff)[zzz]);	\
	}							\
	if ((len + 1) % 16)					\
		pr_debug("\n");					\
}

extern struct list_head g_tiqn_list;
extern spinlock_t tiqn_lock;

/*
 *	Called with cmd->r2t_lock held.
 */
int iscsit_add_r2t_to_list(
	struct iscsi_cmd *cmd,
	u32 offset,
	u32 xfer_len,
	int recovery,
	u32 r2t_sn)
{
	struct iscsi_r2t *r2t;

	r2t = kmem_cache_zalloc(lio_r2t_cache, GFP_ATOMIC);
	if (!r2t) {
		pr_err("Unable to allocate memory for struct iscsi_r2t.\n");
		return -1;
	}
	INIT_LIST_HEAD(&r2t->r2t_list);

	r2t->recovery_r2t = recovery;
	r2t->r2t_sn = (!r2t_sn) ? cmd->r2t_sn++ : r2t_sn;
	r2t->offset = offset;
	r2t->xfer_len = xfer_len;
	list_add_tail(&r2t->r2t_list, &cmd->cmd_r2t_list);
	spin_unlock_bh(&cmd->r2t_lock);

	iscsit_add_cmd_to_immediate_queue(cmd, cmd->conn, ISTATE_SEND_R2T);

	spin_lock_bh(&cmd->r2t_lock);
	return 0;
}

struct iscsi_r2t *iscsit_get_r2t_for_eos(
	struct iscsi_cmd *cmd,
	u32 offset,
	u32 length)
{
	struct iscsi_r2t *r2t;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
		if ((r2t->offset <= offset) &&
		    (r2t->offset + r2t->xfer_len) >= (offset + length)) {
			spin_unlock_bh(&cmd->r2t_lock);
			return r2t;
		}
	}
	spin_unlock_bh(&cmd->r2t_lock);

	pr_err("Unable to locate R2T for Offset: %u, Length:"
			" %u\n", offset, length);
	return NULL;
}

struct iscsi_r2t *iscsit_get_r2t_from_list(struct iscsi_cmd *cmd)
{
	struct iscsi_r2t *r2t;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
		if (!r2t->sent_r2t) {
			spin_unlock_bh(&cmd->r2t_lock);
			return r2t;
		}
	}
	spin_unlock_bh(&cmd->r2t_lock);

	pr_err("Unable to locate next R2T to send for ITT:"
			" 0x%08x.\n", cmd->init_task_tag);
	return NULL;
}

/*
 *	Called with cmd->r2t_lock held.
 */
void iscsit_free_r2t(struct iscsi_r2t *r2t, struct iscsi_cmd *cmd)
{
	list_del(&r2t->r2t_list);
	kmem_cache_free(lio_r2t_cache, r2t);
}

void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
{
	struct iscsi_r2t *r2t, *r2t_tmp;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry_safe(r2t, r2t_tmp, &cmd->cmd_r2t_list, r2t_list)
		iscsit_free_r2t(r2t, cmd);
	spin_unlock_bh(&cmd->r2t_lock);
}

/*
 * May be called from software interrupt (timer) context for allocating
 * iSCSI NopINs.
 */
struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, int state)
{
	struct iscsi_cmd *cmd;
	struct se_session *se_sess = conn->sess->se_sess;
	int size, tag;

	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
	if (tag < 0)
		return NULL;

	size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
	cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size));
	memset(cmd, 0, size);

	cmd->se_cmd.map_tag = tag;
	cmd->conn = conn;
	INIT_LIST_HEAD(&cmd->i_conn_node);
	INIT_LIST_HEAD(&cmd->datain_list);
	INIT_LIST_HEAD(&cmd->cmd_r2t_list);
	spin_lock_init(&cmd->datain_lock);
	spin_lock_init(&cmd->dataout_timeout_lock);
	spin_lock_init(&cmd->istate_lock);
	spin_lock_init(&cmd->error_lock);
	spin_lock_init(&cmd->r2t_lock);

	return cmd;
}
EXPORT_SYMBOL(iscsit_allocate_cmd);

struct iscsi_seq *iscsit_get_seq_holder_for_datain(
	struct iscsi_cmd *cmd,
	u32 seq_send_order)
{
	u32 i;

	for (i = 0; i < cmd->seq_count; i++)
		if (cmd->seq_list[i].seq_send_order == seq_send_order)
			return &cmd->seq_list[i];

	return NULL;
}

struct iscsi_seq *iscsit_get_seq_holder_for_r2t(struct iscsi_cmd *cmd)
{
	u32 i;

	if (!cmd->seq_list) {
		pr_err("struct iscsi_cmd->seq_list is NULL!\n");
		return NULL;
	}

	for (i = 0; i < cmd->seq_count; i++) {
		if (cmd->seq_list[i].type != SEQTYPE_NORMAL)
			continue;
		if (cmd->seq_list[i].seq_send_order == cmd->seq_send_order) {
			cmd->seq_send_order++;
			return &cmd->seq_list[i];
		}
	}

	return NULL;
}

struct iscsi_r2t *iscsit_get_holder_for_r2tsn(
	struct iscsi_cmd *cmd,
	u32 r2t_sn)
{
	struct iscsi_r2t *r2t;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
		if (r2t->r2t_sn == r2t_sn) {
			spin_unlock_bh(&cmd->r2t_lock);
			return r2t;
		}
	}
	spin_unlock_bh(&cmd->r2t_lock);

	return NULL;
}

static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn)
{
	u32 max_cmdsn;
	int ret;

	/*
	 * This is the proper method of checking received CmdSN against
	 * ExpCmdSN and MaxCmdSN values, as well as accounting for out
	 * or order CmdSNs due to multiple connection sessions and/or
	 * CRC failures.
	 */
	max_cmdsn = atomic_read(&sess->max_cmd_sn);
	if (iscsi_sna_gt(cmdsn, max_cmdsn)) {
		pr_err("Received CmdSN: 0x%08x is greater than"
		       " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn, max_cmdsn);
		ret = CMDSN_MAXCMDSN_OVERRUN;

	} else if (cmdsn == sess->exp_cmd_sn) {
		sess->exp_cmd_sn++;
		pr_debug("Received CmdSN matches ExpCmdSN,"
		      " incremented ExpCmdSN to: 0x%08x\n",
		      sess->exp_cmd_sn);
		ret = CMDSN_NORMAL_OPERATION;

	} else if (iscsi_sna_gt(cmdsn, sess->exp_cmd_sn)) {
		pr_debug("Received CmdSN: 0x%08x is greater"
		      " than ExpCmdSN: 0x%08x, not acknowledging.\n",
		      cmdsn, sess->exp_cmd_sn);
		ret = CMDSN_HIGHER_THAN_EXP;

	} else {
		pr_err("Received CmdSN: 0x%08x is less than"
		       " ExpCmdSN: 0x%08x, ignoring.\n", cmdsn,
		       sess->exp_cmd_sn);
		ret = CMDSN_LOWER_THAN_EXP;
	}

	return ret;
}

/*
 * Commands may be received out of order if MC/S is in use.
 * Ensure they are executed in CmdSN order.
 */
int iscsit_sequence_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
			unsigned char *buf, __be32 cmdsn)
{
	int ret, cmdsn_ret;
	bool reject = false;
	u8 reason = ISCSI_REASON_BOOKMARK_NO_RESOURCES;

	mutex_lock(&conn->sess->cmdsn_mutex);

	cmdsn_ret = iscsit_check_received_cmdsn(conn->sess, be32_to_cpu(cmdsn));
	switch (cmdsn_ret) {
	case CMDSN_NORMAL_OPERATION:
		ret = iscsit_execute_cmd(cmd, 0);
		if ((ret >= 0) && !list_empty(&conn->sess->sess_ooo_cmdsn_list))
			iscsit_execute_ooo_cmdsns(conn->sess);
		else if (ret < 0) {
			reject = true;
			ret = CMDSN_ERROR_CANNOT_RECOVER;
		}
		break;
	case CMDSN_HIGHER_THAN_EXP:
		ret = iscsit_handle_ooo_cmdsn(conn->sess, cmd, be32_to_cpu(cmdsn));
		if (ret < 0) {
			reject = true;
			ret = CMDSN_ERROR_CANNOT_RECOVER;
			break;
		}
		ret = CMDSN_HIGHER_THAN_EXP;
		break;
	case CMDSN_LOWER_THAN_EXP:
	case CMDSN_MAXCMDSN_OVERRUN:
	default:
		cmd->i_state = ISTATE_REMOVE;
		iscsit_add_cmd_to_immediate_queue(cmd, conn, cmd->i_state);
		/*
		 * Existing callers for iscsit_sequence_cmd() will silently
		 * ignore commands with CMDSN_LOWER_THAN_EXP, so force this
		 * return for CMDSN_MAXCMDSN_OVERRUN as well..
		 */
		ret = CMDSN_LOWER_THAN_EXP;
		break;
	}
	mutex_unlock(&conn->sess->cmdsn_mutex);

	if (reject)
		iscsit_reject_cmd(cmd, reason, buf);

	return ret;
}
EXPORT_SYMBOL(iscsit_sequence_cmd);

int iscsit_check_unsolicited_dataout(struct iscsi_cmd *cmd, unsigned char *buf)
{
	struct iscsi_conn *conn = cmd->conn;
	struct se_cmd *se_cmd = &cmd->se_cmd;
	struct iscsi_data *hdr = (struct iscsi_data *) buf;
	u32 payload_length = ntoh24(hdr->dlength);

	if (conn->sess->sess_ops->InitialR2T) {
		pr_err("Received unexpected unsolicited data"
			" while InitialR2T=Yes, protocol error.\n");
		transport_send_check_condition_and_sense(se_cmd,
				TCM_UNEXPECTED_UNSOLICITED_DATA, 0);
		return -1;
	}

	if ((cmd->first_burst_len + payload_length) >
	     conn->sess->sess_ops->FirstBurstLength) {
		pr_err("Total %u bytes exceeds FirstBurstLength: %u"
			" for this Unsolicited DataOut Burst.\n",
			(cmd->first_burst_len + payload_length),
				conn->sess->sess_ops->FirstBurstLength);
		transport_send_check_condition_and_sense(se_cmd,
				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
		return -1;
	}

	if (!(hdr->flags & ISCSI_FLAG_CMD_FINAL))
		return 0;

	if (((cmd->first_burst_len + payload_length) != cmd->se_cmd.data_length) &&
	    ((cmd->first_burst_len + payload_length) !=
	      conn->sess->sess_ops->FirstBurstLength)) {
		pr_err("Unsolicited non-immediate data received %u"
			" does not equal FirstBurstLength: %u, and does"
			" not equal ExpXferLen %u.\n",
			(cmd->first_burst_len + payload_length),
			conn->sess->sess_ops->FirstBurstLength, cmd->se_cmd.data_length);
		transport_send_check_condition_and_sense(se_cmd,
				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
		return -1;
	}
	return 0;
}

struct iscsi_cmd *iscsit_find_cmd_from_itt(
	struct iscsi_conn *conn,
	itt_t init_task_tag)
{
	struct iscsi_cmd *cmd;

	spin_lock_bh(&conn->cmd_lock);
	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
		if (cmd->init_task_tag == init_task_tag) {
			spin_unlock_bh(&conn->cmd_lock);
			return cmd;
		}
	}
	spin_unlock_bh(&conn->cmd_lock);

	pr_err("Unable to locate ITT: 0x%08x on CID: %hu",
			init_task_tag, conn->cid);
	return NULL;
}
EXPORT_SYMBOL(iscsit_find_cmd_from_itt);

struct iscsi_cmd *iscsit_find_cmd_from_itt_or_dump(
	struct iscsi_conn *conn,
	itt_t init_task_tag,
	u32 length)
{
	struct iscsi_cmd *cmd;

	spin_lock_bh(&conn->cmd_lock);
	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
		if (cmd->cmd_flags & ICF_GOT_LAST_DATAOUT)
			continue;
		if (cmd->init_task_tag == init_task_tag) {
			spin_unlock_bh(&conn->cmd_lock);
			return cmd;
		}
	}
	spin_unlock_bh(&conn->cmd_lock);

	pr_err("Unable to locate ITT: 0x%08x on CID: %hu,"
			" dumping payload\n", init_task_tag, conn->cid);
	if (length)
		iscsit_dump_data_payload(conn, length, 1);

	return NULL;
}
EXPORT_SYMBOL(iscsit_find_cmd_from_itt_or_dump);

struct iscsi_cmd *iscsit_find_cmd_from_ttt(
	struct iscsi_conn *conn,
	u32 targ_xfer_tag)
{
	struct iscsi_cmd *cmd = NULL;

	spin_lock_bh(&conn->cmd_lock);
	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
		if (cmd->targ_xfer_tag == targ_xfer_tag) {
			spin_unlock_bh(&conn->cmd_lock);
			return cmd;
		}
	}
	spin_unlock_bh(&conn->cmd_lock);

	pr_err("Unable to locate TTT: 0x%08x on CID: %hu\n",
			targ_xfer_tag, conn->cid);
	return NULL;
}

int iscsit_find_cmd_for_recovery(
	struct iscsi_session *sess,
	struct iscsi_cmd **cmd_ptr,
	struct iscsi_conn_recovery **cr_ptr,
	itt_t init_task_tag)
{
	struct iscsi_cmd *cmd = NULL;
	struct iscsi_conn_recovery *cr;
	/*
	 * Scan through the inactive connection recovery list's command list.
	 * If init_task_tag matches the command is still alligent.
	 */
	spin_lock(&sess->cr_i_lock);
	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
		spin_lock(&cr->conn_recovery_cmd_lock);
		list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
			if (cmd->init_task_tag == init_task_tag) {
				spin_unlock(&cr->conn_recovery_cmd_lock);
				spin_unlock(&sess->cr_i_lock);

				*cr_ptr = cr;
				*cmd_ptr = cmd;
				return -2;
			}
		}
		spin_unlock(&cr->conn_recovery_cmd_lock);
	}
	spin_unlock(&sess->cr_i_lock);
	/*
	 * Scan through the active connection recovery list's command list.
	 * If init_task_tag matches the command is ready to be reassigned.
	 */
	spin_lock(&sess->cr_a_lock);
	list_for_each_entry(cr, &sess->cr_active_list, cr_list) {
		spin_lock(&cr->conn_recovery_cmd_lock);
		list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
			if (cmd->init_task_tag == init_task_tag) {
				spin_unlock(&cr->conn_recovery_cmd_lock);
				spin_unlock(&sess->cr_a_lock);

				*cr_ptr = cr;
				*cmd_ptr = cmd;
				return 0;
			}
		}
		spin_unlock(&cr->conn_recovery_cmd_lock);
	}
	spin_unlock(&sess->cr_a_lock);

	return -1;
}

void iscsit_add_cmd_to_immediate_queue(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn,
	u8 state)
{
	struct iscsi_queue_req *qr;

	qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
	if (!qr) {
		pr_err("Unable to allocate memory for"
				" struct iscsi_queue_req\n");
		return;
	}
	INIT_LIST_HEAD(&qr->qr_list);
	qr->cmd = cmd;
	qr->state = state;

	spin_lock_bh(&conn->immed_queue_lock);
	list_add_tail(&qr->qr_list, &conn->immed_queue_list);
	atomic_inc(&cmd->immed_queue_count);
	atomic_set(&conn->check_immediate_queue, 1);
	spin_unlock_bh(&conn->immed_queue_lock);

	wake_up(&conn->queues_wq);
}
EXPORT_SYMBOL(iscsit_add_cmd_to_immediate_queue);

struct iscsi_queue_req *iscsit_get_cmd_from_immediate_queue(struct iscsi_conn *conn)
{
	struct iscsi_queue_req *qr;

	spin_lock_bh(&conn->immed_queue_lock);
	if (list_empty(&conn->immed_queue_list)) {
		spin_unlock_bh(&conn->immed_queue_lock);
		return NULL;
	}
	qr = list_first_entry(&conn->immed_queue_list,
			      struct iscsi_queue_req, qr_list);

	list_del(&qr->qr_list);
	if (qr->cmd)
		atomic_dec(&qr->cmd->immed_queue_count);
	spin_unlock_bh(&conn->immed_queue_lock);

	return qr;
}

static void iscsit_remove_cmd_from_immediate_queue(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn)
{
	struct iscsi_queue_req *qr, *qr_tmp;

	spin_lock_bh(&conn->immed_queue_lock);
	if (!atomic_read(&cmd->immed_queue_count)) {
		spin_unlock_bh(&conn->immed_queue_lock);
		return;
	}

	list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
		if (qr->cmd != cmd)
			continue;

		atomic_dec(&qr->cmd->immed_queue_count);
		list_del(&qr->qr_list);
		kmem_cache_free(lio_qr_cache, qr);
	}
	spin_unlock_bh(&conn->immed_queue_lock);

	if (atomic_read(&cmd->immed_queue_count)) {
		pr_err("ITT: 0x%08x immed_queue_count: %d\n",
			cmd->init_task_tag,
			atomic_read(&cmd->immed_queue_count));
	}
}

void iscsit_add_cmd_to_response_queue(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn,
	u8 state)
{
	struct iscsi_queue_req *qr;

	qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
	if (!qr) {
		pr_err("Unable to allocate memory for"
			" struct iscsi_queue_req\n");
		return;
	}
	INIT_LIST_HEAD(&qr->qr_list);
	qr->cmd = cmd;
	qr->state = state;

	spin_lock_bh(&conn->response_queue_lock);
	list_add_tail(&qr->qr_list, &conn->response_queue_list);
	atomic_inc(&cmd->response_queue_count);
	spin_unlock_bh(&conn->response_queue_lock);

	wake_up(&conn->queues_wq);
}

struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_conn *conn)
{
	struct iscsi_queue_req *qr;

	spin_lock_bh(&conn->response_queue_lock);
	if (list_empty(&conn->response_queue_list)) {
		spin_unlock_bh(&conn->response_queue_lock);
		return NULL;
	}

	qr = list_first_entry(&conn->response_queue_list,
			      struct iscsi_queue_req, qr_list);

	list_del(&qr->qr_list);
	if (qr->cmd)
		atomic_dec(&qr->cmd->response_queue_count);
	spin_unlock_bh(&conn->response_queue_lock);

	return qr;
}

static void iscsit_remove_cmd_from_response_queue(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn)
{
	struct iscsi_queue_req *qr, *qr_tmp;

	spin_lock_bh(&conn->response_queue_lock);
	if (!atomic_read(&cmd->response_queue_count)) {
		spin_unlock_bh(&conn->response_queue_lock);
		return;
	}

	list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
				qr_list) {
		if (qr->cmd != cmd)
			continue;

		atomic_dec(&qr->cmd->response_queue_count);
		list_del(&qr->qr_list);
		kmem_cache_free(lio_qr_cache, qr);
	}
	spin_unlock_bh(&conn->response_queue_lock);

	if (atomic_read(&cmd->response_queue_count)) {
		pr_err("ITT: 0x%08x response_queue_count: %d\n",
			cmd->init_task_tag,
			atomic_read(&cmd->response_queue_count));
	}
}

bool iscsit_conn_all_queues_empty(struct iscsi_conn *conn)
{
	bool empty;

	spin_lock_bh(&conn->immed_queue_lock);
	empty = list_empty(&conn->immed_queue_list);
	spin_unlock_bh(&conn->immed_queue_lock);

	if (!empty)
		return empty;

	spin_lock_bh(&conn->response_queue_lock);
	empty = list_empty(&conn->response_queue_list);
	spin_unlock_bh(&conn->response_queue_lock);

	return empty;
}

void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *conn)
{
	struct iscsi_queue_req *qr, *qr_tmp;

	spin_lock_bh(&conn->immed_queue_lock);
	list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
		list_del(&qr->qr_list);
		if (qr->cmd)
			atomic_dec(&qr->cmd->immed_queue_count);

		kmem_cache_free(lio_qr_cache, qr);
	}
	spin_unlock_bh(&conn->immed_queue_lock);

	spin_lock_bh(&conn->response_queue_lock);
	list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
			qr_list) {
		list_del(&qr->qr_list);
		if (qr->cmd)
			atomic_dec(&qr->cmd->response_queue_count);

		kmem_cache_free(lio_qr_cache, qr);
	}
	spin_unlock_bh(&conn->response_queue_lock);
}

void iscsit_release_cmd(struct iscsi_cmd *cmd)
{
	struct iscsi_session *sess;
	struct se_cmd *se_cmd = &cmd->se_cmd;

	if (cmd->conn)
		sess = cmd->conn->sess;
	else
		sess = cmd->sess;

	BUG_ON(!sess || !sess->se_sess);

	kfree(cmd->buf_ptr);
	kfree(cmd->pdu_list);
	kfree(cmd->seq_list);
	kfree(cmd->tmr_req);
	kfree(cmd->iov_data);
	kfree(cmd->text_in_ptr);

	percpu_ida_free(&sess->se_sess->sess_tag_pool, se_cmd->map_tag);
}
EXPORT_SYMBOL(iscsit_release_cmd);

void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
		       bool check_queues)
{
	struct iscsi_conn *conn = cmd->conn;

	if (scsi_cmd) {
		if (cmd->data_direction == DMA_TO_DEVICE) {
			iscsit_stop_dataout_timer(cmd);
			iscsit_free_r2ts_from_list(cmd);
		}
		if (cmd->data_direction == DMA_FROM_DEVICE)
			iscsit_free_all_datain_reqs(cmd);
	}

	if (conn && check_queues) {
		iscsit_remove_cmd_from_immediate_queue(cmd, conn);
		iscsit_remove_cmd_from_response_queue(cmd, conn);
	}

	if (conn && conn->conn_transport->iscsit_release_cmd)
		conn->conn_transport->iscsit_release_cmd(conn, cmd);
}

void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
{
	struct se_cmd *se_cmd = NULL;
	int rc;
	/*
	 * Determine if a struct se_cmd is associated with
	 * this struct iscsi_cmd.
	 */
	switch (cmd->iscsi_opcode) {
	case ISCSI_OP_SCSI_CMD:
		se_cmd = &cmd->se_cmd;
		__iscsit_free_cmd(cmd, true, shutdown);
		/*
		 * Fallthrough
		 */
	case ISCSI_OP_SCSI_TMFUNC:
		rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
		if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
			__iscsit_free_cmd(cmd, true, shutdown);
			target_put_sess_cmd(se_cmd);
		}
		break;
	case ISCSI_OP_REJECT:
		/*
		 * Handle special case for REJECT when iscsi_add_reject*() has
		 * overwritten the original iscsi_opcode assignment, and the
		 * associated cmd->se_cmd needs to be released.
		 */
		if (cmd->se_cmd.se_tfo != NULL) {
			se_cmd = &cmd->se_cmd;
			__iscsit_free_cmd(cmd, true, shutdown);

			rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
			if (!rc && shutdown && se_cmd->se_sess) {
				__iscsit_free_cmd(cmd, true, shutdown);
				target_put_sess_cmd(se_cmd);
			}
			break;
		}
		/* Fall-through */
	default:
		__iscsit_free_cmd(cmd, false, shutdown);
		iscsit_release_cmd(cmd);
		break;
	}
}
EXPORT_SYMBOL(iscsit_free_cmd);

int iscsit_check_session_usage_count(struct iscsi_session *sess)
{
	spin_lock_bh(&sess->session_usage_lock);
	if (sess->session_usage_count != 0) {
		sess->session_waiting_on_uc = 1;
		spin_unlock_bh(&sess->session_usage_lock);
		if (in_interrupt())
			return 2;

		wait_for_completion(&sess->session_waiting_on_uc_comp);
		return 1;
	}
	spin_unlock_bh(&sess->session_usage_lock);

	return 0;
}

void iscsit_dec_session_usage_count(struct iscsi_session *sess)
{
	spin_lock_bh(&sess->session_usage_lock);
	sess->session_usage_count--;

	if (!sess->session_usage_count && sess->session_waiting_on_uc)
		complete(&sess->session_waiting_on_uc_comp);

	spin_unlock_bh(&sess->session_usage_lock);
}

void iscsit_inc_session_usage_count(struct iscsi_session *sess)
{
	spin_lock_bh(&sess->session_usage_lock);
	sess->session_usage_count++;
	spin_unlock_bh(&sess->session_usage_lock);
}

struct iscsi_conn *iscsit_get_conn_from_cid(struct iscsi_session *sess, u16 cid)
{
	struct iscsi_conn *conn;

	spin_lock_bh(&sess->conn_lock);
	list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
		if ((conn->cid == cid) &&
		    (conn->conn_state == TARG_CONN_STATE_LOGGED_IN)) {
			iscsit_inc_conn_usage_count(conn);
			spin_unlock_bh(&sess->conn_lock);
			return conn;
		}
	}
	spin_unlock_bh(&sess->conn_lock);

	return NULL;
}

struct iscsi_conn *iscsit_get_conn_from_cid_rcfr(struct iscsi_session *sess, u16 cid)
{
	struct iscsi_conn *conn;

	spin_lock_bh(&sess->conn_lock);
	list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
		if (conn->cid == cid) {
			iscsit_inc_conn_usage_count(conn);
			spin_lock(&conn->state_lock);
			atomic_set(&conn->connection_wait_rcfr, 1);
			spin_unlock(&conn->state_lock);
			spin_unlock_bh(&sess->conn_lock);
			return conn;
		}
	}
	spin_unlock_bh(&sess->conn_lock);

	return NULL;
}

void iscsit_check_conn_usage_count(struct iscsi_conn *conn)
{
	spin_lock_bh(&conn->conn_usage_lock);
	if (conn->conn_usage_count != 0) {
		conn->conn_waiting_on_uc = 1;
		spin_unlock_bh(&conn->conn_usage_lock);

		wait_for_completion(&conn->conn_waiting_on_uc_comp);
		return;
	}
	spin_unlock_bh(&conn->conn_usage_lock);
}

void iscsit_dec_conn_usage_count(struct iscsi_conn *conn)
{
	spin_lock_bh(&conn->conn_usage_lock);
	conn->conn_usage_count--;

	if (!conn->conn_usage_count && conn->conn_waiting_on_uc)
		complete(&conn->conn_waiting_on_uc_comp);

	spin_unlock_bh(&conn->conn_usage_lock);
}

void iscsit_inc_conn_usage_count(struct iscsi_conn *conn)
{
	spin_lock_bh(&conn->conn_usage_lock);
	conn->conn_usage_count++;
	spin_unlock_bh(&conn->conn_usage_lock);
}

static int iscsit_add_nopin(struct iscsi_conn *conn, int want_response)
{
	u8 state;
	struct iscsi_cmd *cmd;

	cmd = iscsit_allocate_cmd(conn, TASK_RUNNING);
	if (!cmd)
		return -1;

	cmd->iscsi_opcode = ISCSI_OP_NOOP_IN;
	state = (want_response) ? ISTATE_SEND_NOPIN_WANT_RESPONSE :
				ISTATE_SEND_NOPIN_NO_RESPONSE;
	cmd->init_task_tag = RESERVED_ITT;
	cmd->targ_xfer_tag = (want_response) ?
			     session_get_next_ttt(conn->sess) : 0xFFFFFFFF;
	spin_lock_bh(&conn->cmd_lock);
	list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
	spin_unlock_bh(&conn->cmd_lock);

	if (want_response)
		iscsit_start_nopin_response_timer(conn);
	iscsit_add_cmd_to_immediate_queue(cmd, conn, state);

	return 0;
}

static void iscsit_handle_nopin_response_timeout(unsigned long data)
{
	struct iscsi_conn *conn = (struct iscsi_conn *) data;

	iscsit_inc_conn_usage_count(conn);

	spin_lock_bh(&conn->nopin_timer_lock);
	if (conn->nopin_response_timer_flags & ISCSI_TF_STOP) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		iscsit_dec_conn_usage_count(conn);
		return;
	}

	pr_debug("Did not receive response to NOPIN on CID: %hu on"
		" SID: %u, failing connection.\n", conn->cid,
			conn->sess->sid);
	conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
	spin_unlock_bh(&conn->nopin_timer_lock);

	{
	struct iscsi_portal_group *tpg = conn->sess->tpg;
	struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;

	if (tiqn) {
		spin_lock_bh(&tiqn->sess_err_stats.lock);
		strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
				conn->sess->sess_ops->InitiatorName);
		tiqn->sess_err_stats.last_sess_failure_type =
				ISCSI_SESS_ERR_CXN_TIMEOUT;
		tiqn->sess_err_stats.cxn_timeout_errors++;
		atomic_long_inc(&conn->sess->conn_timeout_errors);
		spin_unlock_bh(&tiqn->sess_err_stats.lock);
	}
	}

	iscsit_cause_connection_reinstatement(conn, 0);
	iscsit_dec_conn_usage_count(conn);
}

void iscsit_mod_nopin_response_timer(struct iscsi_conn *conn)
{
	struct iscsi_session *sess = conn->sess;
	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);

	spin_lock_bh(&conn->nopin_timer_lock);
	if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		return;
	}

	mod_timer(&conn->nopin_response_timer,
		(get_jiffies_64() + na->nopin_response_timeout * HZ));
	spin_unlock_bh(&conn->nopin_timer_lock);
}

/*
 *	Called with conn->nopin_timer_lock held.
 */
void iscsit_start_nopin_response_timer(struct iscsi_conn *conn)
{
	struct iscsi_session *sess = conn->sess;
	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);

	spin_lock_bh(&conn->nopin_timer_lock);
	if (conn->nopin_response_timer_flags & ISCSI_TF_RUNNING) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		return;
	}

	init_timer(&conn->nopin_response_timer);
	conn->nopin_response_timer.expires =
		(get_jiffies_64() + na->nopin_response_timeout * HZ);
	conn->nopin_response_timer.data = (unsigned long)conn;
	conn->nopin_response_timer.function = iscsit_handle_nopin_response_timeout;
	conn->nopin_response_timer_flags &= ~ISCSI_TF_STOP;
	conn->nopin_response_timer_flags |= ISCSI_TF_RUNNING;
	add_timer(&conn->nopin_response_timer);

	pr_debug("Started NOPIN Response Timer on CID: %d to %u"
		" seconds\n", conn->cid, na->nopin_response_timeout);
	spin_unlock_bh(&conn->nopin_timer_lock);
}

void iscsit_stop_nopin_response_timer(struct iscsi_conn *conn)
{
	spin_lock_bh(&conn->nopin_timer_lock);
	if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		return;
	}
	conn->nopin_response_timer_flags |= ISCSI_TF_STOP;
	spin_unlock_bh(&conn->nopin_timer_lock);

	del_timer_sync(&conn->nopin_response_timer);

	spin_lock_bh(&conn->nopin_timer_lock);
	conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
	spin_unlock_bh(&conn->nopin_timer_lock);
}

static void iscsit_handle_nopin_timeout(unsigned long data)
{
	struct iscsi_conn *conn = (struct iscsi_conn *) data;

	iscsit_inc_conn_usage_count(conn);

	spin_lock_bh(&conn->nopin_timer_lock);
	if (conn->nopin_timer_flags & ISCSI_TF_STOP) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		iscsit_dec_conn_usage_count(conn);
		return;
	}
	conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
	spin_unlock_bh(&conn->nopin_timer_lock);

	iscsit_add_nopin(conn, 1);
	iscsit_dec_conn_usage_count(conn);
}

/*
 * Called with conn->nopin_timer_lock held.
 */
void __iscsit_start_nopin_timer(struct iscsi_conn *conn)
{
	struct iscsi_session *sess = conn->sess;
	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
	/*
	* NOPIN timeout is disabled.
	 */
	if (!na->nopin_timeout)
		return;

	if (conn->nopin_timer_flags & ISCSI_TF_RUNNING)
		return;

	init_timer(&conn->nopin_timer);
	conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
	conn->nopin_timer.data = (unsigned long)conn;
	conn->nopin_timer.function = iscsit_handle_nopin_timeout;
	conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
	conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
	add_timer(&conn->nopin_timer);

	pr_debug("Started NOPIN Timer on CID: %d at %u second"
		" interval\n", conn->cid, na->nopin_timeout);
}

void iscsit_start_nopin_timer(struct iscsi_conn *conn)
{
	struct iscsi_session *sess = conn->sess;
	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
	/*
	 * NOPIN timeout is disabled..
	 */
	if (!na->nopin_timeout)
		return;

	spin_lock_bh(&conn->nopin_timer_lock);
	if (conn->nopin_timer_flags & ISCSI_TF_RUNNING) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		return;
	}

	init_timer(&conn->nopin_timer);
	conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
	conn->nopin_timer.data = (unsigned long)conn;
	conn->nopin_timer.function = iscsit_handle_nopin_timeout;
	conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
	conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
	add_timer(&conn->nopin_timer);

	pr_debug("Started NOPIN Timer on CID: %d at %u second"
			" interval\n", conn->cid, na->nopin_timeout);
	spin_unlock_bh(&conn->nopin_timer_lock);
}

void iscsit_stop_nopin_timer(struct iscsi_conn *conn)
{
	spin_lock_bh(&conn->nopin_timer_lock);
	if (!(conn->nopin_timer_flags & ISCSI_TF_RUNNING)) {
		spin_unlock_bh(&conn->nopin_timer_lock);
		return;
	}
	conn->nopin_timer_flags |= ISCSI_TF_STOP;
	spin_unlock_bh(&conn->nopin_timer_lock);

	del_timer_sync(&conn->nopin_timer);

	spin_lock_bh(&conn->nopin_timer_lock);
	conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
	spin_unlock_bh(&conn->nopin_timer_lock);
}

int iscsit_send_tx_data(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn,
	int use_misc)
{
	int tx_sent, tx_size;
	u32 iov_count;
	struct kvec *iov;

send_data:
	tx_size = cmd->tx_size;

	if (!use_misc) {
		iov = &cmd->iov_data[0];
		iov_count = cmd->iov_data_count;
	} else {
		iov = &cmd->iov_misc[0];
		iov_count = cmd->iov_misc_count;
	}

	tx_sent = tx_data(conn, &iov[0], iov_count, tx_size);
	if (tx_size != tx_sent) {
		if (tx_sent == -EAGAIN) {
			pr_err("tx_data() returned -EAGAIN\n");
			goto send_data;
		} else
			return -1;
	}
	cmd->tx_size = 0;

	return 0;
}

int iscsit_fe_sendpage_sg(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn)
{
	struct scatterlist *sg = cmd->first_data_sg;
	struct kvec iov;
	u32 tx_hdr_size, data_len;
	u32 offset = cmd->first_data_sg_off;
	int tx_sent, iov_off;

send_hdr:
	tx_hdr_size = ISCSI_HDR_LEN;
	if (conn->conn_ops->HeaderDigest)
		tx_hdr_size += ISCSI_CRC_LEN;

	iov.iov_base = cmd->pdu;
	iov.iov_len = tx_hdr_size;

	tx_sent = tx_data(conn, &iov, 1, tx_hdr_size);
	if (tx_hdr_size != tx_sent) {
		if (tx_sent == -EAGAIN) {
			pr_err("tx_data() returned -EAGAIN\n");
			goto send_hdr;
		}
		return -1;
	}

	data_len = cmd->tx_size - tx_hdr_size - cmd->padding;
	/*
	 * Set iov_off used by padding and data digest tx_data() calls below
	 * in order to determine proper offset into cmd->iov_data[]
	 */
	if (conn->conn_ops->DataDigest) {
		data_len -= ISCSI_CRC_LEN;
		if (cmd->padding)
			iov_off = (cmd->iov_data_count - 2);
		else
			iov_off = (cmd->iov_data_count - 1);
	} else {
		iov_off = (cmd->iov_data_count - 1);
	}
	/*
	 * Perform sendpage() for each page in the scatterlist
	 */
	while (data_len) {
		u32 space = (sg->length - offset);
		u32 sub_len = min_t(u32, data_len, space);
send_pg:
		tx_sent = conn->sock->ops->sendpage(conn->sock,
					sg_page(sg), sg->offset + offset, sub_len, 0);
		if (tx_sent != sub_len) {
			if (tx_sent == -EAGAIN) {
				pr_err("tcp_sendpage() returned"
						" -EAGAIN\n");
				goto send_pg;
			}

			pr_err("tcp_sendpage() failure: %d\n",
					tx_sent);
			return -1;
		}

		data_len -= sub_len;
		offset = 0;
		sg = sg_next(sg);
	}

send_padding:
	if (cmd->padding) {
		struct kvec *iov_p = &cmd->iov_data[iov_off++];

		tx_sent = tx_data(conn, iov_p, 1, cmd->padding);
		if (cmd->padding != tx_sent) {
			if (tx_sent == -EAGAIN) {
				pr_err("tx_data() returned -EAGAIN\n");
				goto send_padding;
			}
			return -1;
		}
	}

send_datacrc:
	if (conn->conn_ops->DataDigest) {
		struct kvec *iov_d = &cmd->iov_data[iov_off];

		tx_sent = tx_data(conn, iov_d, 1, ISCSI_CRC_LEN);
		if (ISCSI_CRC_LEN != tx_sent) {
			if (tx_sent == -EAGAIN) {
				pr_err("tx_data() returned -EAGAIN\n");
				goto send_datacrc;
			}
			return -1;
		}
	}

	return 0;
}

/*
 *      This function is used for mainly sending a ISCSI_TARG_LOGIN_RSP PDU
 *      back to the Initiator when an expection condition occurs with the
 *      errors set in status_class and status_detail.
 *
 *      Parameters:     iSCSI Connection, Status Class, Status Detail.
 *      Returns:        0 on success, -1 on error.
 */
int iscsit_tx_login_rsp(struct iscsi_conn *conn, u8 status_class, u8 status_detail)
{
	struct iscsi_login_rsp *hdr;
	struct iscsi_login *login = conn->conn_login;

	login->login_failed = 1;
	iscsit_collect_login_stats(conn, status_class, status_detail);

	memset(&login->rsp[0], 0, ISCSI_HDR_LEN);

	hdr	= (struct iscsi_login_rsp *)&login->rsp[0];
	hdr->opcode		= ISCSI_OP_LOGIN_RSP;
	hdr->status_class	= status_class;
	hdr->status_detail	= status_detail;
	hdr->itt		= conn->login_itt;

	return conn->conn_transport->iscsit_put_login_tx(conn, login, 0);
}

void iscsit_print_session_params(struct iscsi_session *sess)
{
	struct iscsi_conn *conn;

	pr_debug("-----------------------------[Session Params for"
		" SID: %u]-----------------------------\n", sess->sid);
	spin_lock_bh(&sess->conn_lock);
	list_for_each_entry(conn, &sess->sess_conn_list, conn_list)
		iscsi_dump_conn_ops(conn->conn_ops);
	spin_unlock_bh(&sess->conn_lock);

	iscsi_dump_sess_ops(sess->sess_ops);
}

static int iscsit_do_rx_data(
	struct iscsi_conn *conn,
	struct iscsi_data_count *count)
{
	int data = count->data_length, rx_loop = 0, total_rx = 0;
	struct msghdr msg;

	if (!conn || !conn->sock || !conn->conn_ops)
		return -1;

	memset(&msg, 0, sizeof(struct msghdr));
	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC,
		      count->iov, count->iov_count, data);

	while (msg_data_left(&msg)) {
		rx_loop = sock_recvmsg(conn->sock, &msg, MSG_WAITALL);
		if (rx_loop <= 0) {
			pr_debug("rx_loop: %d total_rx: %d\n",
				rx_loop, total_rx);
			return rx_loop;
		}
		total_rx += rx_loop;
		pr_debug("rx_loop: %d, total_rx: %d, data: %d\n",
				rx_loop, total_rx, data);
	}

	return total_rx;
}

int rx_data(
	struct iscsi_conn *conn,
	struct kvec *iov,
	int iov_count,
	int data)
{
	struct iscsi_data_count c;

	if (!conn || !conn->sock || !conn->conn_ops)
		return -1;

	memset(&c, 0, sizeof(struct iscsi_data_count));
	c.iov = iov;
	c.iov_count = iov_count;
	c.data_length = data;
	c.type = ISCSI_RX_DATA;

	return iscsit_do_rx_data(conn, &c);
}

int tx_data(
	struct iscsi_conn *conn,
	struct kvec *iov,
	int iov_count,
	int data)
{
	struct msghdr msg;
	int total_tx = 0;

	if (!conn || !conn->sock || !conn->conn_ops)
		return -1;

	if (data <= 0) {
		pr_err("Data length is: %d\n", data);
		return -1;
	}

	memset(&msg, 0, sizeof(struct msghdr));

	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC,
		      iov, iov_count, data);

	while (msg_data_left(&msg)) {
		int tx_loop = sock_sendmsg(conn->sock, &msg);
		if (tx_loop <= 0) {
			pr_debug("tx_loop: %d total_tx %d\n",
				tx_loop, total_tx);
			return tx_loop;
		}
		total_tx += tx_loop;
		pr_debug("tx_loop: %d, total_tx: %d, data: %d\n",
					tx_loop, total_tx, data);
	}

	return total_tx;
}

void iscsit_collect_login_stats(
	struct iscsi_conn *conn,
	u8 status_class,
	u8 status_detail)
{
	struct iscsi_param *intrname = NULL;
	struct iscsi_tiqn *tiqn;
	struct iscsi_login_stats *ls;

	tiqn = iscsit_snmp_get_tiqn(conn);
	if (!tiqn)
		return;

	ls = &tiqn->login_stats;

	spin_lock(&ls->lock);
	if (status_class == ISCSI_STATUS_CLS_SUCCESS)
		ls->accepts++;
	else if (status_class == ISCSI_STATUS_CLS_REDIRECT) {
		ls->redirects++;
		ls->last_fail_type = ISCSI_LOGIN_FAIL_REDIRECT;
	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
		 (status_detail == ISCSI_LOGIN_STATUS_AUTH_FAILED)) {
		ls->authenticate_fails++;
		ls->last_fail_type =  ISCSI_LOGIN_FAIL_AUTHENTICATE;
	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
		 (status_detail == ISCSI_LOGIN_STATUS_TGT_FORBIDDEN)) {
		ls->authorize_fails++;
		ls->last_fail_type = ISCSI_LOGIN_FAIL_AUTHORIZE;
	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR) &&
		 (status_detail == ISCSI_LOGIN_STATUS_INIT_ERR)) {
		ls->negotiate_fails++;
		ls->last_fail_type = ISCSI_LOGIN_FAIL_NEGOTIATE;
	} else {
		ls->other_fails++;
		ls->last_fail_type = ISCSI_LOGIN_FAIL_OTHER;
	}

	/* Save initiator name, ip address and time, if it is a failed login */
	if (status_class != ISCSI_STATUS_CLS_SUCCESS) {
		if (conn->param_list)
			intrname = iscsi_find_param_from_key(INITIATORNAME,
							     conn->param_list);
		strlcpy(ls->last_intr_fail_name,
		       (intrname ? intrname->value : "Unknown"),
		       sizeof(ls->last_intr_fail_name));

		ls->last_intr_fail_ip_family = conn->login_family;

		ls->last_intr_fail_sockaddr = conn->login_sockaddr;
		ls->last_fail_time = get_jiffies_64();
	}

	spin_unlock(&ls->lock);
}

struct iscsi_tiqn *iscsit_snmp_get_tiqn(struct iscsi_conn *conn)
{
	struct iscsi_portal_group *tpg;

	if (!conn)
		return NULL;

	tpg = conn->tpg;
	if (!tpg)
		return NULL;

	if (!tpg->tpg_tiqn)
		return NULL;

	return tpg->tpg_tiqn;
}