summaryrefslogtreecommitdiff
path: root/net/smc/smc_llc.c
blob: fa8cd57a9b32cd88676fc4ccf468a0e35219f552 (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
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
// SPDX-License-Identifier: GPL-2.0
/*
 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  Link Layer Control (LLC)
 *
 *  Copyright IBM Corp. 2016
 *
 *  Author(s):  Klaus Wacker <Klaus.Wacker@de.ibm.com>
 *              Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <net/tcp.h>
#include <rdma/ib_verbs.h>

#include "smc.h"
#include "smc_core.h"
#include "smc_clc.h"
#include "smc_llc.h"
#include "smc_pnet.h"

#define SMC_LLC_DATA_LEN		40

struct smc_llc_hdr {
	struct smc_wr_rx_hdr common;
	u8 length;	/* 44 */
#if defined(__BIG_ENDIAN_BITFIELD)
	u8 reserved:4,
	   add_link_rej_rsn:4;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
	u8 add_link_rej_rsn:4,
	   reserved:4;
#endif
	u8 flags;
};

#define SMC_LLC_FLAG_NO_RMBE_EYEC	0x03

struct smc_llc_msg_confirm_link {	/* type 0x01 */
	struct smc_llc_hdr hd;
	u8 sender_mac[ETH_ALEN];
	u8 sender_gid[SMC_GID_SIZE];
	u8 sender_qp_num[3];
	u8 link_num;
	u8 link_uid[SMC_LGR_ID_SIZE];
	u8 max_links;
	u8 reserved[9];
};

#define SMC_LLC_FLAG_ADD_LNK_REJ	0x40
#define SMC_LLC_REJ_RSN_NO_ALT_PATH	1

#define SMC_LLC_ADD_LNK_MAX_LINKS	2

struct smc_llc_msg_add_link {		/* type 0x02 */
	struct smc_llc_hdr hd;
	u8 sender_mac[ETH_ALEN];
	u8 reserved2[2];
	u8 sender_gid[SMC_GID_SIZE];
	u8 sender_qp_num[3];
	u8 link_num;
#if defined(__BIG_ENDIAN_BITFIELD)
	u8 reserved3 : 4,
	   qp_mtu   : 4;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
	u8 qp_mtu   : 4,
	   reserved3 : 4;
#endif
	u8 initial_psn[3];
	u8 reserved[8];
};

struct smc_llc_msg_add_link_cont_rt {
	__be32 rmb_key;
	__be32 rmb_key_new;
	__be64 rmb_vaddr_new;
};

#define SMC_LLC_RKEYS_PER_CONT_MSG	2

struct smc_llc_msg_add_link_cont {	/* type 0x03 */
	struct smc_llc_hdr hd;
	u8 link_num;
	u8 num_rkeys;
	u8 reserved2[2];
	struct smc_llc_msg_add_link_cont_rt rt[SMC_LLC_RKEYS_PER_CONT_MSG];
	u8 reserved[4];
} __packed;			/* format defined in RFC7609 */

#define SMC_LLC_FLAG_DEL_LINK_ALL	0x40
#define SMC_LLC_FLAG_DEL_LINK_ORDERLY	0x20

struct smc_llc_msg_del_link {		/* type 0x04 */
	struct smc_llc_hdr hd;
	u8 link_num;
	__be32 reason;
	u8 reserved[35];
} __packed;			/* format defined in RFC7609 */

struct smc_llc_msg_test_link {		/* type 0x07 */
	struct smc_llc_hdr hd;
	u8 user_data[16];
	u8 reserved[24];
};

struct smc_rmb_rtoken {
	union {
		u8 num_rkeys;	/* first rtoken byte of CONFIRM LINK msg */
				/* is actually the num of rtokens, first */
				/* rtoken is always for the current link */
		u8 link_id;	/* link id of the rtoken */
	};
	__be32 rmb_key;
	__be64 rmb_vaddr;
} __packed;			/* format defined in RFC7609 */

#define SMC_LLC_RKEYS_PER_MSG	3

struct smc_llc_msg_confirm_rkey {	/* type 0x06 */
	struct smc_llc_hdr hd;
	struct smc_rmb_rtoken rtoken[SMC_LLC_RKEYS_PER_MSG];
	u8 reserved;
};

#define SMC_LLC_DEL_RKEY_MAX	8
#define SMC_LLC_FLAG_RKEY_RETRY	0x10
#define SMC_LLC_FLAG_RKEY_NEG	0x20

struct smc_llc_msg_delete_rkey {	/* type 0x09 */
	struct smc_llc_hdr hd;
	u8 num_rkeys;
	u8 err_mask;
	u8 reserved[2];
	__be32 rkey[8];
	u8 reserved2[4];
};

union smc_llc_msg {
	struct smc_llc_msg_confirm_link confirm_link;
	struct smc_llc_msg_add_link add_link;
	struct smc_llc_msg_add_link_cont add_link_cont;
	struct smc_llc_msg_del_link delete_link;

	struct smc_llc_msg_confirm_rkey confirm_rkey;
	struct smc_llc_msg_delete_rkey delete_rkey;

	struct smc_llc_msg_test_link test_link;
	struct {
		struct smc_llc_hdr hdr;
		u8 data[SMC_LLC_DATA_LEN];
	} raw;
};

#define SMC_LLC_FLAG_RESP		0x80

struct smc_llc_qentry {
	struct list_head list;
	struct smc_link *link;
	union smc_llc_msg msg;
};

static void smc_llc_enqueue(struct smc_link *link, union smc_llc_msg *llc);

struct smc_llc_qentry *smc_llc_flow_qentry_clr(struct smc_llc_flow *flow)
{
	struct smc_llc_qentry *qentry = flow->qentry;

	flow->qentry = NULL;
	return qentry;
}

void smc_llc_flow_qentry_del(struct smc_llc_flow *flow)
{
	struct smc_llc_qentry *qentry;

	if (flow->qentry) {
		qentry = flow->qentry;
		flow->qentry = NULL;
		kfree(qentry);
	}
}

static inline void smc_llc_flow_qentry_set(struct smc_llc_flow *flow,
					   struct smc_llc_qentry *qentry)
{
	flow->qentry = qentry;
}

static void smc_llc_flow_parallel(struct smc_link_group *lgr, u8 flow_type,
				  struct smc_llc_qentry *qentry)
{
	u8 msg_type = qentry->msg.raw.hdr.common.type;

	if ((msg_type == SMC_LLC_ADD_LINK || msg_type == SMC_LLC_DELETE_LINK) &&
	    flow_type != msg_type && !lgr->delayed_event) {
		lgr->delayed_event = qentry;
		return;
	}
	/* drop parallel or already-in-progress llc requests */
	if (flow_type != msg_type)
		pr_warn_once("smc: SMC-R lg %*phN dropped parallel "
			     "LLC msg: msg %d flow %d role %d\n",
			     SMC_LGR_ID_SIZE, &lgr->id,
			     qentry->msg.raw.hdr.common.type,
			     flow_type, lgr->role);
	kfree(qentry);
}

/* try to start a new llc flow, initiated by an incoming llc msg */
static bool smc_llc_flow_start(struct smc_llc_flow *flow,
			       struct smc_llc_qentry *qentry)
{
	struct smc_link_group *lgr = qentry->link->lgr;

	spin_lock_bh(&lgr->llc_flow_lock);
	if (flow->type) {
		/* a flow is already active */
		smc_llc_flow_parallel(lgr, flow->type, qentry);
		spin_unlock_bh(&lgr->llc_flow_lock);
		return false;
	}
	switch (qentry->msg.raw.hdr.common.type) {
	case SMC_LLC_ADD_LINK:
		flow->type = SMC_LLC_FLOW_ADD_LINK;
		break;
	case SMC_LLC_DELETE_LINK:
		flow->type = SMC_LLC_FLOW_DEL_LINK;
		break;
	case SMC_LLC_CONFIRM_RKEY:
	case SMC_LLC_DELETE_RKEY:
		flow->type = SMC_LLC_FLOW_RKEY;
		break;
	default:
		flow->type = SMC_LLC_FLOW_NONE;
	}
	if (qentry == lgr->delayed_event)
		lgr->delayed_event = NULL;
	smc_llc_flow_qentry_set(flow, qentry);
	spin_unlock_bh(&lgr->llc_flow_lock);
	return true;
}

/* start a new local llc flow, wait till current flow finished */
int smc_llc_flow_initiate(struct smc_link_group *lgr,
			  enum smc_llc_flowtype type)
{
	enum smc_llc_flowtype allowed_remote = SMC_LLC_FLOW_NONE;
	int rc;

	/* all flows except confirm_rkey and delete_rkey are exclusive,
	 * confirm/delete rkey flows can run concurrently (local and remote)
	 */
	if (type == SMC_LLC_FLOW_RKEY)
		allowed_remote = SMC_LLC_FLOW_RKEY;
again:
	if (list_empty(&lgr->list))
		return -ENODEV;
	spin_lock_bh(&lgr->llc_flow_lock);
	if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
	    (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
	     lgr->llc_flow_rmt.type == allowed_remote)) {
		lgr->llc_flow_lcl.type = type;
		spin_unlock_bh(&lgr->llc_flow_lock);
		return 0;
	}
	spin_unlock_bh(&lgr->llc_flow_lock);
	rc = wait_event_timeout(lgr->llc_flow_waiter, (list_empty(&lgr->list) ||
				(lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
				 (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
				  lgr->llc_flow_rmt.type == allowed_remote))),
				SMC_LLC_WAIT_TIME * 10);
	if (!rc)
		return -ETIMEDOUT;
	goto again;
}

/* finish the current llc flow */
void smc_llc_flow_stop(struct smc_link_group *lgr, struct smc_llc_flow *flow)
{
	spin_lock_bh(&lgr->llc_flow_lock);
	memset(flow, 0, sizeof(*flow));
	flow->type = SMC_LLC_FLOW_NONE;
	spin_unlock_bh(&lgr->llc_flow_lock);
	if (!list_empty(&lgr->list) && lgr->delayed_event &&
	    flow == &lgr->llc_flow_lcl)
		schedule_work(&lgr->llc_event_work);
	else
		wake_up(&lgr->llc_flow_waiter);
}

/* lnk is optional and used for early wakeup when link goes down, useful in
 * cases where we wait for a response on the link after we sent a request
 */
struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
				    struct smc_link *lnk,
				    int time_out, u8 exp_msg)
{
	struct smc_llc_flow *flow = &lgr->llc_flow_lcl;
	u8 rcv_msg;

	wait_event_timeout(lgr->llc_msg_waiter,
			   (flow->qentry ||
			    (lnk && !smc_link_usable(lnk)) ||
			    list_empty(&lgr->list)),
			   time_out);
	if (!flow->qentry ||
	    (lnk && !smc_link_usable(lnk)) || list_empty(&lgr->list)) {
		smc_llc_flow_qentry_del(flow);
		goto out;
	}
	rcv_msg = flow->qentry->msg.raw.hdr.common.type;
	if (exp_msg && rcv_msg != exp_msg) {
		if (exp_msg == SMC_LLC_ADD_LINK &&
		    rcv_msg == SMC_LLC_DELETE_LINK) {
			/* flow_start will delay the unexpected msg */
			smc_llc_flow_start(&lgr->llc_flow_lcl,
					   smc_llc_flow_qentry_clr(flow));
			return NULL;
		}
		pr_warn_once("smc: SMC-R lg %*phN dropped unexpected LLC msg: "
			     "msg %d exp %d flow %d role %d flags %x\n",
			     SMC_LGR_ID_SIZE, &lgr->id, rcv_msg, exp_msg,
			     flow->type, lgr->role,
			     flow->qentry->msg.raw.hdr.flags);
		smc_llc_flow_qentry_del(flow);
	}
out:
	return flow->qentry;
}

/********************************** send *************************************/

struct smc_llc_tx_pend {
};

/* handler for send/transmission completion of an LLC msg */
static void smc_llc_tx_handler(struct smc_wr_tx_pend_priv *pend,
			       struct smc_link *link,
			       enum ib_wc_status wc_status)
{
	/* future work: handle wc_status error for recovery and failover */
}

/**
 * smc_llc_add_pending_send() - add LLC control message to pending WQE transmits
 * @link: Pointer to SMC link used for sending LLC control message.
 * @wr_buf: Out variable returning pointer to work request payload buffer.
 * @pend: Out variable returning pointer to private pending WR tracking.
 *	  It's the context the transmit complete handler will get.
 *
 * Reserves and pre-fills an entry for a pending work request send/tx.
 * Used by mid-level smc_llc_send_msg() to prepare for later actual send/tx.
 * Can sleep due to smc_get_ctrl_buf (if not in softirq context).
 *
 * Return: 0 on success, otherwise an error value.
 */
static int smc_llc_add_pending_send(struct smc_link *link,
				    struct smc_wr_buf **wr_buf,
				    struct smc_wr_tx_pend_priv **pend)
{
	int rc;

	rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, NULL,
				     pend);
	if (rc < 0)
		return rc;
	BUILD_BUG_ON_MSG(
		sizeof(union smc_llc_msg) > SMC_WR_BUF_SIZE,
		"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_llc_msg)");
	BUILD_BUG_ON_MSG(
		sizeof(union smc_llc_msg) != SMC_WR_TX_SIZE,
		"must adapt SMC_WR_TX_SIZE to sizeof(struct smc_llc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()");
	BUILD_BUG_ON_MSG(
		sizeof(struct smc_llc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
		"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_llc_tx_pend)");
	return 0;
}

/* high-level API to send LLC confirm link */
int smc_llc_send_confirm_link(struct smc_link *link,
			      enum smc_llc_reqresp reqresp)
{
	struct smc_llc_msg_confirm_link *confllc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
	memset(confllc, 0, sizeof(*confllc));
	confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
	confllc->hd.length = sizeof(struct smc_llc_msg_confirm_link);
	confllc->hd.flags |= SMC_LLC_FLAG_NO_RMBE_EYEC;
	if (reqresp == SMC_LLC_RESP)
		confllc->hd.flags |= SMC_LLC_FLAG_RESP;
	memcpy(confllc->sender_mac, link->smcibdev->mac[link->ibport - 1],
	       ETH_ALEN);
	memcpy(confllc->sender_gid, link->gid, SMC_GID_SIZE);
	hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
	confllc->link_num = link->link_id;
	memcpy(confllc->link_uid, link->link_uid, SMC_LGR_ID_SIZE);
	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS;
	/* send llc message */
	rc = smc_wr_tx_send(link, pend);
	return rc;
}

/* send LLC confirm rkey request */
static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
				     struct smc_buf_desc *rmb_desc)
{
	struct smc_llc_msg_confirm_rkey *rkeyllc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	struct smc_link *link;
	int i, rc, rtok_ix;

	rc = smc_llc_add_pending_send(send_link, &wr_buf, &pend);
	if (rc)
		return rc;
	rkeyllc = (struct smc_llc_msg_confirm_rkey *)wr_buf;
	memset(rkeyllc, 0, sizeof(*rkeyllc));
	rkeyllc->hd.common.type = SMC_LLC_CONFIRM_RKEY;
	rkeyllc->hd.length = sizeof(struct smc_llc_msg_confirm_rkey);

	rtok_ix = 1;
	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
		link = &send_link->lgr->lnk[i];
		if (link->state == SMC_LNK_ACTIVE && link != send_link) {
			rkeyllc->rtoken[rtok_ix].link_id = link->link_id;
			rkeyllc->rtoken[rtok_ix].rmb_key =
				htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
			rkeyllc->rtoken[rtok_ix].rmb_vaddr = cpu_to_be64(
				(u64)sg_dma_address(
					rmb_desc->sgt[link->link_idx].sgl));
			rtok_ix++;
		}
	}
	/* rkey of send_link is in rtoken[0] */
	rkeyllc->rtoken[0].num_rkeys = rtok_ix - 1;
	rkeyllc->rtoken[0].rmb_key =
		htonl(rmb_desc->mr_rx[send_link->link_idx]->rkey);
	rkeyllc->rtoken[0].rmb_vaddr = cpu_to_be64(
		(u64)sg_dma_address(rmb_desc->sgt[send_link->link_idx].sgl));
	/* send llc message */
	rc = smc_wr_tx_send(send_link, pend);
	return rc;
}

/* send LLC delete rkey request */
static int smc_llc_send_delete_rkey(struct smc_link *link,
				    struct smc_buf_desc *rmb_desc)
{
	struct smc_llc_msg_delete_rkey *rkeyllc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	rkeyllc = (struct smc_llc_msg_delete_rkey *)wr_buf;
	memset(rkeyllc, 0, sizeof(*rkeyllc));
	rkeyllc->hd.common.type = SMC_LLC_DELETE_RKEY;
	rkeyllc->hd.length = sizeof(struct smc_llc_msg_delete_rkey);
	rkeyllc->num_rkeys = 1;
	rkeyllc->rkey[0] = htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
	/* send llc message */
	rc = smc_wr_tx_send(link, pend);
	return rc;
}

/* send ADD LINK request or response */
int smc_llc_send_add_link(struct smc_link *link, u8 mac[], u8 gid[],
			  struct smc_link *link_new,
			  enum smc_llc_reqresp reqresp)
{
	struct smc_llc_msg_add_link *addllc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	addllc = (struct smc_llc_msg_add_link *)wr_buf;

	memset(addllc, 0, sizeof(*addllc));
	addllc->hd.common.type = SMC_LLC_ADD_LINK;
	addllc->hd.length = sizeof(struct smc_llc_msg_add_link);
	if (reqresp == SMC_LLC_RESP)
		addllc->hd.flags |= SMC_LLC_FLAG_RESP;
	memcpy(addllc->sender_mac, mac, ETH_ALEN);
	memcpy(addllc->sender_gid, gid, SMC_GID_SIZE);
	if (link_new) {
		addllc->link_num = link_new->link_id;
		hton24(addllc->sender_qp_num, link_new->roce_qp->qp_num);
		hton24(addllc->initial_psn, link_new->psn_initial);
		if (reqresp == SMC_LLC_REQ)
			addllc->qp_mtu = link_new->path_mtu;
		else
			addllc->qp_mtu = min(link_new->path_mtu,
					     link_new->peer_mtu);
	}
	/* send llc message */
	rc = smc_wr_tx_send(link, pend);
	return rc;
}

/* send DELETE LINK request or response */
int smc_llc_send_delete_link(struct smc_link *link, u8 link_del_id,
			     enum smc_llc_reqresp reqresp, bool orderly,
			     u32 reason)
{
	struct smc_llc_msg_del_link *delllc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	delllc = (struct smc_llc_msg_del_link *)wr_buf;

	memset(delllc, 0, sizeof(*delllc));
	delllc->hd.common.type = SMC_LLC_DELETE_LINK;
	delllc->hd.length = sizeof(struct smc_llc_msg_del_link);
	if (reqresp == SMC_LLC_RESP)
		delllc->hd.flags |= SMC_LLC_FLAG_RESP;
	if (orderly)
		delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
	if (link_del_id)
		delllc->link_num = link_del_id;
	else
		delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ALL;
	delllc->reason = htonl(reason);
	/* send llc message */
	rc = smc_wr_tx_send(link, pend);
	return rc;
}

/* send LLC test link request */
static int smc_llc_send_test_link(struct smc_link *link, u8 user_data[16])
{
	struct smc_llc_msg_test_link *testllc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	testllc = (struct smc_llc_msg_test_link *)wr_buf;
	memset(testllc, 0, sizeof(*testllc));
	testllc->hd.common.type = SMC_LLC_TEST_LINK;
	testllc->hd.length = sizeof(struct smc_llc_msg_test_link);
	memcpy(testllc->user_data, user_data, sizeof(testllc->user_data));
	/* send llc message */
	rc = smc_wr_tx_send(link, pend);
	return rc;
}

/* schedule an llc send on link, may wait for buffers */
static int smc_llc_send_message(struct smc_link *link, void *llcbuf)
{
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	if (!smc_link_usable(link))
		return -ENOLINK;
	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	memcpy(wr_buf, llcbuf, sizeof(union smc_llc_msg));
	return smc_wr_tx_send(link, pend);
}

/* schedule an llc send on link, may wait for buffers,
 * and wait for send completion notification.
 * @return 0 on success
 */
static int smc_llc_send_message_wait(struct smc_link *link, void *llcbuf)
{
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	if (!smc_link_usable(link))
		return -ENOLINK;
	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	memcpy(wr_buf, llcbuf, sizeof(union smc_llc_msg));
	return smc_wr_tx_send_wait(link, pend, SMC_LLC_WAIT_TIME);
}

/********************************* receive ***********************************/

static int smc_llc_alloc_alt_link(struct smc_link_group *lgr,
				  enum smc_lgr_type lgr_new_t)
{
	int i;

	if (lgr->type == SMC_LGR_SYMMETRIC ||
	    (lgr->type != SMC_LGR_SINGLE &&
	     (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
	      lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)))
		return -EMLINK;

	if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
	    lgr_new_t == SMC_LGR_ASYMMETRIC_PEER) {
		for (i = SMC_LINKS_PER_LGR_MAX - 1; i >= 0; i--)
			if (lgr->lnk[i].state == SMC_LNK_UNUSED)
				return i;
	} else {
		for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++)
			if (lgr->lnk[i].state == SMC_LNK_UNUSED)
				return i;
	}
	return -EMLINK;
}

/* return first buffer from any of the next buf lists */
static struct smc_buf_desc *_smc_llc_get_next_rmb(struct smc_link_group *lgr,
						  int *buf_lst)
{
	struct smc_buf_desc *buf_pos;

	while (*buf_lst < SMC_RMBE_SIZES) {
		buf_pos = list_first_entry_or_null(&lgr->rmbs[*buf_lst],
						   struct smc_buf_desc, list);
		if (buf_pos)
			return buf_pos;
		(*buf_lst)++;
	}
	return NULL;
}

/* return next rmb from buffer lists */
static struct smc_buf_desc *smc_llc_get_next_rmb(struct smc_link_group *lgr,
						 int *buf_lst,
						 struct smc_buf_desc *buf_pos)
{
	struct smc_buf_desc *buf_next;

	if (!buf_pos || list_is_last(&buf_pos->list, &lgr->rmbs[*buf_lst])) {
		(*buf_lst)++;
		return _smc_llc_get_next_rmb(lgr, buf_lst);
	}
	buf_next = list_next_entry(buf_pos, list);
	return buf_next;
}

static struct smc_buf_desc *smc_llc_get_first_rmb(struct smc_link_group *lgr,
						  int *buf_lst)
{
	*buf_lst = 0;
	return smc_llc_get_next_rmb(lgr, buf_lst, NULL);
}

/* send one add_link_continue msg */
static int smc_llc_add_link_cont(struct smc_link *link,
				 struct smc_link *link_new, u8 *num_rkeys_todo,
				 int *buf_lst, struct smc_buf_desc **buf_pos)
{
	struct smc_llc_msg_add_link_cont *addc_llc;
	struct smc_link_group *lgr = link->lgr;
	int prim_lnk_idx, lnk_idx, i, rc;
	struct smc_wr_tx_pend_priv *pend;
	struct smc_wr_buf *wr_buf;
	struct smc_buf_desc *rmb;
	u8 n;

	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
	if (rc)
		return rc;
	addc_llc = (struct smc_llc_msg_add_link_cont *)wr_buf;
	memset(addc_llc, 0, sizeof(*addc_llc));

	prim_lnk_idx = link->link_idx;
	lnk_idx = link_new->link_idx;
	addc_llc->link_num = link_new->link_id;
	addc_llc->num_rkeys = *num_rkeys_todo;
	n = *num_rkeys_todo;
	for (i = 0; i < min_t(u8, n, SMC_LLC_RKEYS_PER_CONT_MSG); i++) {
		if (!*buf_pos) {
			addc_llc->num_rkeys = addc_llc->num_rkeys -
					      *num_rkeys_todo;
			*num_rkeys_todo = 0;
			break;
		}
		rmb = *buf_pos;

		addc_llc->rt[i].rmb_key = htonl(rmb->mr_rx[prim_lnk_idx]->rkey);
		addc_llc->rt[i].rmb_key_new = htonl(rmb->mr_rx[lnk_idx]->rkey);
		addc_llc->rt[i].rmb_vaddr_new =
			cpu_to_be64((u64)sg_dma_address(rmb->sgt[lnk_idx].sgl));

		(*num_rkeys_todo)--;
		*buf_pos = smc_llc_get_next_rmb(lgr, buf_lst, *buf_pos);
		while (*buf_pos && !(*buf_pos)->used)
			*buf_pos = smc_llc_get_next_rmb(lgr, buf_lst, *buf_pos);
	}
	addc_llc->hd.common.type = SMC_LLC_ADD_LINK_CONT;
	addc_llc->hd.length = sizeof(struct smc_llc_msg_add_link_cont);
	if (lgr->role == SMC_CLNT)
		addc_llc->hd.flags |= SMC_LLC_FLAG_RESP;
	return smc_wr_tx_send(link, pend);
}

static int smc_llc_cli_rkey_exchange(struct smc_link *link,
				     struct smc_link *link_new)
{
	struct smc_llc_msg_add_link_cont *addc_llc;
	struct smc_link_group *lgr = link->lgr;
	u8 max, num_rkeys_send, num_rkeys_recv;
	struct smc_llc_qentry *qentry;
	struct smc_buf_desc *buf_pos;
	int buf_lst;
	int rc = 0;
	int i;

	mutex_lock(&lgr->rmbs_lock);
	num_rkeys_send = lgr->conns_num;
	buf_pos = smc_llc_get_first_rmb(lgr, &buf_lst);
	do {
		qentry = smc_llc_wait(lgr, NULL, SMC_LLC_WAIT_TIME,
				      SMC_LLC_ADD_LINK_CONT);
		if (!qentry) {
			rc = -ETIMEDOUT;
			break;
		}
		addc_llc = &qentry->msg.add_link_cont;
		num_rkeys_recv = addc_llc->num_rkeys;
		max = min_t(u8, num_rkeys_recv, SMC_LLC_RKEYS_PER_CONT_MSG);
		for (i = 0; i < max; i++) {
			smc_rtoken_set(lgr, link->link_idx, link_new->link_idx,
				       addc_llc->rt[i].rmb_key,
				       addc_llc->rt[i].rmb_vaddr_new,
				       addc_llc->rt[i].rmb_key_new);
			num_rkeys_recv--;
		}
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		rc = smc_llc_add_link_cont(link, link_new, &num_rkeys_send,
					   &buf_lst, &buf_pos);
		if (rc)
			break;
	} while (num_rkeys_send || num_rkeys_recv);

	mutex_unlock(&lgr->rmbs_lock);
	return rc;
}

/* prepare and send an add link reject response */
static int smc_llc_cli_add_link_reject(struct smc_llc_qentry *qentry)
{
	qentry->msg.raw.hdr.flags |= SMC_LLC_FLAG_RESP;
	qentry->msg.raw.hdr.flags |= SMC_LLC_FLAG_ADD_LNK_REJ;
	qentry->msg.raw.hdr.add_link_rej_rsn = SMC_LLC_REJ_RSN_NO_ALT_PATH;
	return smc_llc_send_message(qentry->link, &qentry->msg);
}

static int smc_llc_cli_conf_link(struct smc_link *link,
				 struct smc_init_info *ini,
				 struct smc_link *link_new,
				 enum smc_lgr_type lgr_new_t)
{
	struct smc_link_group *lgr = link->lgr;
	struct smc_llc_qentry *qentry = NULL;
	int rc = 0;

	/* receive CONFIRM LINK request over RoCE fabric */
	qentry = smc_llc_wait(lgr, NULL, SMC_LLC_WAIT_FIRST_TIME, 0);
	if (!qentry) {
		rc = smc_llc_send_delete_link(link, link_new->link_id,
					      SMC_LLC_REQ, false,
					      SMC_LLC_DEL_LOST_PATH);
		return -ENOLINK;
	}
	if (qentry->msg.raw.hdr.common.type != SMC_LLC_CONFIRM_LINK) {
		/* received DELETE_LINK instead */
		qentry->msg.raw.hdr.flags |= SMC_LLC_FLAG_RESP;
		smc_llc_send_message(link, &qentry->msg);
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		return -ENOLINK;
	}
	smc_llc_save_peer_uid(qentry);
	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);

	rc = smc_ib_modify_qp_rts(link_new);
	if (rc) {
		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
					 false, SMC_LLC_DEL_LOST_PATH);
		return -ENOLINK;
	}
	smc_wr_remember_qp_attr(link_new);

	rc = smcr_buf_reg_lgr(link_new);
	if (rc) {
		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
					 false, SMC_LLC_DEL_LOST_PATH);
		return -ENOLINK;
	}

	/* send CONFIRM LINK response over RoCE fabric */
	rc = smc_llc_send_confirm_link(link_new, SMC_LLC_RESP);
	if (rc) {
		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
					 false, SMC_LLC_DEL_LOST_PATH);
		return -ENOLINK;
	}
	smc_llc_link_active(link_new);
	if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
	    lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)
		smcr_lgr_set_type_asym(lgr, lgr_new_t, link_new->link_idx);
	else
		smcr_lgr_set_type(lgr, lgr_new_t);
	return 0;
}

static void smc_llc_save_add_link_info(struct smc_link *link,
				       struct smc_llc_msg_add_link *add_llc)
{
	link->peer_qpn = ntoh24(add_llc->sender_qp_num);
	memcpy(link->peer_gid, add_llc->sender_gid, SMC_GID_SIZE);
	memcpy(link->peer_mac, add_llc->sender_mac, ETH_ALEN);
	link->peer_psn = ntoh24(add_llc->initial_psn);
	link->peer_mtu = add_llc->qp_mtu;
}

/* as an SMC client, process an add link request */
int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
{
	struct smc_llc_msg_add_link *llc = &qentry->msg.add_link;
	enum smc_lgr_type lgr_new_t = SMC_LGR_SYMMETRIC;
	struct smc_link_group *lgr = smc_get_lgr(link);
	struct smc_link *lnk_new = NULL;
	struct smc_init_info ini;
	int lnk_idx, rc = 0;

	ini.vlan_id = lgr->vlan_id;
	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
	if (!memcmp(llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
	    !memcmp(llc->sender_mac, link->peer_mac, ETH_ALEN)) {
		if (!ini.ib_dev)
			goto out_reject;
		lgr_new_t = SMC_LGR_ASYMMETRIC_PEER;
	}
	if (!ini.ib_dev) {
		lgr_new_t = SMC_LGR_ASYMMETRIC_LOCAL;
		ini.ib_dev = link->smcibdev;
		ini.ib_port = link->ibport;
	}
	lnk_idx = smc_llc_alloc_alt_link(lgr, lgr_new_t);
	if (lnk_idx < 0)
		goto out_reject;
	lnk_new = &lgr->lnk[lnk_idx];
	rc = smcr_link_init(lgr, lnk_new, lnk_idx, &ini);
	if (rc)
		goto out_reject;
	smc_llc_save_add_link_info(lnk_new, llc);
	lnk_new->link_id = llc->link_num;	/* SMC server assigns link id */
	smc_llc_link_set_uid(lnk_new);

	rc = smc_ib_ready_link(lnk_new);
	if (rc)
		goto out_clear_lnk;

	rc = smcr_buf_map_lgr(lnk_new);
	if (rc)
		goto out_clear_lnk;

	rc = smc_llc_send_add_link(link,
				   lnk_new->smcibdev->mac[ini.ib_port - 1],
				   lnk_new->gid, lnk_new, SMC_LLC_RESP);
	if (rc)
		goto out_clear_lnk;
	rc = smc_llc_cli_rkey_exchange(link, lnk_new);
	if (rc) {
		rc = 0;
		goto out_clear_lnk;
	}
	rc = smc_llc_cli_conf_link(link, &ini, lnk_new, lgr_new_t);
	if (!rc)
		goto out;
out_clear_lnk:
	smcr_link_clear(lnk_new, false);
out_reject:
	smc_llc_cli_add_link_reject(qentry);
out:
	kfree(qentry);
	return rc;
}

/* as an SMC client, invite server to start the add_link processing */
static void smc_llc_cli_add_link_invite(struct smc_link *link,
					struct smc_llc_qentry *qentry)
{
	struct smc_link_group *lgr = smc_get_lgr(link);
	struct smc_init_info ini;

	if (lgr->type == SMC_LGR_SYMMETRIC ||
	    lgr->type == SMC_LGR_ASYMMETRIC_PEER)
		goto out;

	ini.vlan_id = lgr->vlan_id;
	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
	if (!ini.ib_dev)
		goto out;

	smc_llc_send_add_link(link, ini.ib_dev->mac[ini.ib_port - 1],
			      ini.ib_gid, NULL, SMC_LLC_REQ);
out:
	kfree(qentry);
}

static bool smc_llc_is_local_add_link(union smc_llc_msg *llc)
{
	if (llc->raw.hdr.common.type == SMC_LLC_ADD_LINK &&
	    !llc->add_link.qp_mtu && !llc->add_link.link_num)
		return true;
	return false;
}

static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
{
	struct smc_llc_qentry *qentry;

	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);

	mutex_lock(&lgr->llc_conf_mutex);
	if (smc_llc_is_local_add_link(&qentry->msg))
		smc_llc_cli_add_link_invite(qentry->link, qentry);
	else
		smc_llc_cli_add_link(qentry->link, qentry);
	mutex_unlock(&lgr->llc_conf_mutex);
}

static int smc_llc_active_link_count(struct smc_link_group *lgr)
{
	int i, link_count = 0;

	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
		if (!smc_link_usable(&lgr->lnk[i]))
			continue;
		link_count++;
	}
	return link_count;
}

/* find the asymmetric link when 3 links are established  */
static struct smc_link *smc_llc_find_asym_link(struct smc_link_group *lgr)
{
	int asym_idx = -ENOENT;
	int i, j, k;
	bool found;

	/* determine asymmetric link */
	found = false;
	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
		for (j = i + 1; j < SMC_LINKS_PER_LGR_MAX; j++) {
			if (!smc_link_usable(&lgr->lnk[i]) ||
			    !smc_link_usable(&lgr->lnk[j]))
				continue;
			if (!memcmp(lgr->lnk[i].gid, lgr->lnk[j].gid,
				    SMC_GID_SIZE)) {
				found = true;	/* asym_lnk is i or j */
				break;
			}
		}
		if (found)
			break;
	}
	if (!found)
		goto out; /* no asymmetric link */
	for (k = 0; k < SMC_LINKS_PER_LGR_MAX; k++) {
		if (!smc_link_usable(&lgr->lnk[k]))
			continue;
		if (k != i &&
		    !memcmp(lgr->lnk[i].peer_gid, lgr->lnk[k].peer_gid,
			    SMC_GID_SIZE)) {
			asym_idx = i;
			break;
		}
		if (k != j &&
		    !memcmp(lgr->lnk[j].peer_gid, lgr->lnk[k].peer_gid,
			    SMC_GID_SIZE)) {
			asym_idx = j;
			break;
		}
	}
out:
	return (asym_idx < 0) ? NULL : &lgr->lnk[asym_idx];
}

static void smc_llc_delete_asym_link(struct smc_link_group *lgr)
{
	struct smc_link *lnk_new = NULL, *lnk_asym;
	struct smc_llc_qentry *qentry;
	int rc;

	lnk_asym = smc_llc_find_asym_link(lgr);
	if (!lnk_asym)
		return; /* no asymmetric link */
	if (!smc_link_downing(&lnk_asym->state))
		return;
	lnk_new = smc_switch_conns(lgr, lnk_asym, false);
	smc_wr_tx_wait_no_pending_sends(lnk_asym);
	if (!lnk_new)
		goto out_free;
	/* change flow type from ADD_LINK into DEL_LINK */
	lgr->llc_flow_lcl.type = SMC_LLC_FLOW_DEL_LINK;
	rc = smc_llc_send_delete_link(lnk_new, lnk_asym->link_id, SMC_LLC_REQ,
				      true, SMC_LLC_DEL_NO_ASYM_NEEDED);
	if (rc) {
		smcr_link_down_cond(lnk_new);
		goto out_free;
	}
	qentry = smc_llc_wait(lgr, lnk_new, SMC_LLC_WAIT_TIME,
			      SMC_LLC_DELETE_LINK);
	if (!qentry) {
		smcr_link_down_cond(lnk_new);
		goto out_free;
	}
	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
out_free:
	smcr_link_clear(lnk_asym, true);
}

static int smc_llc_srv_rkey_exchange(struct smc_link *link,
				     struct smc_link *link_new)
{
	struct smc_llc_msg_add_link_cont *addc_llc;
	struct smc_link_group *lgr = link->lgr;
	u8 max, num_rkeys_send, num_rkeys_recv;
	struct smc_llc_qentry *qentry = NULL;
	struct smc_buf_desc *buf_pos;
	int buf_lst;
	int rc = 0;
	int i;

	mutex_lock(&lgr->rmbs_lock);
	num_rkeys_send = lgr->conns_num;
	buf_pos = smc_llc_get_first_rmb(lgr, &buf_lst);
	do {
		smc_llc_add_link_cont(link, link_new, &num_rkeys_send,
				      &buf_lst, &buf_pos);
		qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_TIME,
				      SMC_LLC_ADD_LINK_CONT);
		if (!qentry) {
			rc = -ETIMEDOUT;
			goto out;
		}
		addc_llc = &qentry->msg.add_link_cont;
		num_rkeys_recv = addc_llc->num_rkeys;
		max = min_t(u8, num_rkeys_recv, SMC_LLC_RKEYS_PER_CONT_MSG);
		for (i = 0; i < max; i++) {
			smc_rtoken_set(lgr, link->link_idx, link_new->link_idx,
				       addc_llc->rt[i].rmb_key,
				       addc_llc->rt[i].rmb_vaddr_new,
				       addc_llc->rt[i].rmb_key_new);
			num_rkeys_recv--;
		}
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
	} while (num_rkeys_send || num_rkeys_recv);
out:
	mutex_unlock(&lgr->rmbs_lock);
	return rc;
}

static int smc_llc_srv_conf_link(struct smc_link *link,
				 struct smc_link *link_new,
				 enum smc_lgr_type lgr_new_t)
{
	struct smc_link_group *lgr = link->lgr;
	struct smc_llc_qentry *qentry = NULL;
	int rc;

	/* send CONFIRM LINK request over the RoCE fabric */
	rc = smc_llc_send_confirm_link(link_new, SMC_LLC_REQ);
	if (rc)
		return -ENOLINK;
	/* receive CONFIRM LINK response over the RoCE fabric */
	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_FIRST_TIME, 0);
	if (!qentry ||
	    qentry->msg.raw.hdr.common.type != SMC_LLC_CONFIRM_LINK) {
		/* send DELETE LINK */
		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
					 false, SMC_LLC_DEL_LOST_PATH);
		if (qentry)
			smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		return -ENOLINK;
	}
	smc_llc_save_peer_uid(qentry);
	smc_llc_link_active(link_new);
	if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
	    lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)
		smcr_lgr_set_type_asym(lgr, lgr_new_t, link_new->link_idx);
	else
		smcr_lgr_set_type(lgr, lgr_new_t);
	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
	return 0;
}

int smc_llc_srv_add_link(struct smc_link *link)
{
	enum smc_lgr_type lgr_new_t = SMC_LGR_SYMMETRIC;
	struct smc_link_group *lgr = link->lgr;
	struct smc_llc_msg_add_link *add_llc;
	struct smc_llc_qentry *qentry = NULL;
	struct smc_link *link_new;
	struct smc_init_info ini;
	int lnk_idx, rc = 0;

	/* ignore client add link recommendation, start new flow */
	ini.vlan_id = lgr->vlan_id;
	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
	if (!ini.ib_dev) {
		lgr_new_t = SMC_LGR_ASYMMETRIC_LOCAL;
		ini.ib_dev = link->smcibdev;
		ini.ib_port = link->ibport;
	}
	lnk_idx = smc_llc_alloc_alt_link(lgr, lgr_new_t);
	if (lnk_idx < 0)
		return 0;

	rc = smcr_link_init(lgr, &lgr->lnk[lnk_idx], lnk_idx, &ini);
	if (rc)
		return rc;
	link_new = &lgr->lnk[lnk_idx];
	rc = smc_llc_send_add_link(link,
				   link_new->smcibdev->mac[ini.ib_port - 1],
				   link_new->gid, link_new, SMC_LLC_REQ);
	if (rc)
		goto out_err;
	/* receive ADD LINK response over the RoCE fabric */
	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_TIME, SMC_LLC_ADD_LINK);
	if (!qentry) {
		rc = -ETIMEDOUT;
		goto out_err;
	}
	add_llc = &qentry->msg.add_link;
	if (add_llc->hd.flags & SMC_LLC_FLAG_ADD_LNK_REJ) {
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		rc = -ENOLINK;
		goto out_err;
	}
	if (lgr->type == SMC_LGR_SINGLE &&
	    (!memcmp(add_llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
	     !memcmp(add_llc->sender_mac, link->peer_mac, ETH_ALEN))) {
		lgr_new_t = SMC_LGR_ASYMMETRIC_PEER;
	}
	smc_llc_save_add_link_info(link_new, add_llc);
	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);

	rc = smc_ib_ready_link(link_new);
	if (rc)
		goto out_err;
	rc = smcr_buf_map_lgr(link_new);
	if (rc)
		goto out_err;
	rc = smcr_buf_reg_lgr(link_new);
	if (rc)
		goto out_err;
	rc = smc_llc_srv_rkey_exchange(link, link_new);
	if (rc)
		goto out_err;
	rc = smc_llc_srv_conf_link(link, link_new, lgr_new_t);
	if (rc)
		goto out_err;
	return 0;
out_err:
	smcr_link_clear(link_new, false);
	return rc;
}

static void smc_llc_process_srv_add_link(struct smc_link_group *lgr)
{
	struct smc_link *link = lgr->llc_flow_lcl.qentry->link;
	int rc;

	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);

	mutex_lock(&lgr->llc_conf_mutex);
	rc = smc_llc_srv_add_link(link);
	if (!rc && lgr->type == SMC_LGR_SYMMETRIC) {
		/* delete any asymmetric link */
		smc_llc_delete_asym_link(lgr);
	}
	mutex_unlock(&lgr->llc_conf_mutex);
}

/* enqueue a local add_link req to trigger a new add_link flow */
void smc_llc_add_link_local(struct smc_link *link)
{
	struct smc_llc_msg_add_link add_llc = {0};

	add_llc.hd.length = sizeof(add_llc);
	add_llc.hd.common.type = SMC_LLC_ADD_LINK;
	/* no dev and port needed */
	smc_llc_enqueue(link, (union smc_llc_msg *)&add_llc);
}

/* worker to process an add link message */
static void smc_llc_add_link_work(struct work_struct *work)
{
	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
						  llc_add_link_work);

	if (list_empty(&lgr->list)) {
		/* link group is terminating */
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		goto out;
	}

	if (lgr->role == SMC_CLNT)
		smc_llc_process_cli_add_link(lgr);
	else
		smc_llc_process_srv_add_link(lgr);
out:
	smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl);
}

/* enqueue a local del_link msg to trigger a new del_link flow,
 * called only for role SMC_SERV
 */
void smc_llc_srv_delete_link_local(struct smc_link *link, u8 del_link_id)
{
	struct smc_llc_msg_del_link del_llc = {0};

	del_llc.hd.length = sizeof(del_llc);
	del_llc.hd.common.type = SMC_LLC_DELETE_LINK;
	del_llc.link_num = del_link_id;
	del_llc.reason = htonl(SMC_LLC_DEL_LOST_PATH);
	del_llc.hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
	smc_llc_enqueue(link, (union smc_llc_msg *)&del_llc);
}

static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr)
{
	struct smc_link *lnk_del = NULL, *lnk_asym, *lnk;
	struct smc_llc_msg_del_link *del_llc;
	struct smc_llc_qentry *qentry;
	int active_links;
	int lnk_idx;

	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
	lnk = qentry->link;
	del_llc = &qentry->msg.delete_link;

	if (del_llc->hd.flags & SMC_LLC_FLAG_DEL_LINK_ALL) {
		smc_lgr_terminate_sched(lgr);
		goto out;
	}
	mutex_lock(&lgr->llc_conf_mutex);
	/* delete single link */
	for (lnk_idx = 0; lnk_idx < SMC_LINKS_PER_LGR_MAX; lnk_idx++) {
		if (lgr->lnk[lnk_idx].link_id != del_llc->link_num)
			continue;
		lnk_del = &lgr->lnk[lnk_idx];
		break;
	}
	del_llc->hd.flags |= SMC_LLC_FLAG_RESP;
	if (!lnk_del) {
		/* link was not found */
		del_llc->reason = htonl(SMC_LLC_DEL_NOLNK);
		smc_llc_send_message(lnk, &qentry->msg);
		goto out_unlock;
	}
	lnk_asym = smc_llc_find_asym_link(lgr);

	del_llc->reason = 0;
	smc_llc_send_message(lnk, &qentry->msg); /* response */

	if (smc_link_downing(&lnk_del->state)) {
		if (smc_switch_conns(lgr, lnk_del, false))
			smc_wr_tx_wait_no_pending_sends(lnk_del);
	}
	smcr_link_clear(lnk_del, true);

	active_links = smc_llc_active_link_count(lgr);
	if (lnk_del == lnk_asym) {
		/* expected deletion of asym link, don't change lgr state */
	} else if (active_links == 1) {
		smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
	} else if (!active_links) {
		smcr_lgr_set_type(lgr, SMC_LGR_NONE);
		smc_lgr_terminate_sched(lgr);
	}
out_unlock:
	mutex_unlock(&lgr->llc_conf_mutex);
out:
	kfree(qentry);
}

/* try to send a DELETE LINK ALL request on any active link,
 * waiting for send completion
 */
void smc_llc_send_link_delete_all(struct smc_link_group *lgr, bool ord, u32 rsn)
{
	struct smc_llc_msg_del_link delllc = {0};
	int i;

	delllc.hd.common.type = SMC_LLC_DELETE_LINK;
	delllc.hd.length = sizeof(delllc);
	if (ord)
		delllc.hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
	delllc.hd.flags |= SMC_LLC_FLAG_DEL_LINK_ALL;
	delllc.reason = htonl(rsn);

	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
		if (!smc_link_usable(&lgr->lnk[i]))
			continue;
		if (!smc_llc_send_message_wait(&lgr->lnk[i], &delllc))
			break;
	}
}

static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr)
{
	struct smc_llc_msg_del_link *del_llc;
	struct smc_link *lnk, *lnk_del;
	struct smc_llc_qentry *qentry;
	int active_links;
	int i;

	mutex_lock(&lgr->llc_conf_mutex);
	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
	lnk = qentry->link;
	del_llc = &qentry->msg.delete_link;

	if (qentry->msg.delete_link.hd.flags & SMC_LLC_FLAG_DEL_LINK_ALL) {
		/* delete entire lgr */
		smc_llc_send_link_delete_all(lgr, true, ntohl(
					      qentry->msg.delete_link.reason));
		smc_lgr_terminate_sched(lgr);
		goto out;
	}
	/* delete single link */
	lnk_del = NULL;
	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
		if (lgr->lnk[i].link_id == del_llc->link_num) {
			lnk_del = &lgr->lnk[i];
			break;
		}
	}
	if (!lnk_del)
		goto out; /* asymmetric link already deleted */

	if (smc_link_downing(&lnk_del->state)) {
		if (smc_switch_conns(lgr, lnk_del, false))
			smc_wr_tx_wait_no_pending_sends(lnk_del);
	}
	if (!list_empty(&lgr->list)) {
		/* qentry is either a request from peer (send it back to
		 * initiate the DELETE_LINK processing), or a locally
		 * enqueued DELETE_LINK request (forward it)
		 */
		if (!smc_llc_send_message(lnk, &qentry->msg)) {
			struct smc_llc_qentry *qentry2;

			qentry2 = smc_llc_wait(lgr, lnk, SMC_LLC_WAIT_TIME,
					       SMC_LLC_DELETE_LINK);
			if (qentry2)
				smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		}
	}
	smcr_link_clear(lnk_del, true);

	active_links = smc_llc_active_link_count(lgr);
	if (active_links == 1) {
		smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
	} else if (!active_links) {
		smcr_lgr_set_type(lgr, SMC_LGR_NONE);
		smc_lgr_terminate_sched(lgr);
	}

	if (lgr->type == SMC_LGR_SINGLE && !list_empty(&lgr->list)) {
		/* trigger setup of asymm alt link */
		smc_llc_add_link_local(lnk);
	}
out:
	mutex_unlock(&lgr->llc_conf_mutex);
	kfree(qentry);
}

static void smc_llc_delete_link_work(struct work_struct *work)
{
	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
						  llc_del_link_work);

	if (list_empty(&lgr->list)) {
		/* link group is terminating */
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
		goto out;
	}

	if (lgr->role == SMC_CLNT)
		smc_llc_process_cli_delete_link(lgr);
	else
		smc_llc_process_srv_delete_link(lgr);
out:
	smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl);
}

/* process a confirm_rkey request from peer, remote flow */
static void smc_llc_rmt_conf_rkey(struct smc_link_group *lgr)
{
	struct smc_llc_msg_confirm_rkey *llc;
	struct smc_llc_qentry *qentry;
	struct smc_link *link;
	int num_entries;
	int rk_idx;
	int i;

	qentry = lgr->llc_flow_rmt.qentry;
	llc = &qentry->msg.confirm_rkey;
	link = qentry->link;

	num_entries = llc->rtoken[0].num_rkeys;
	/* first rkey entry is for receiving link */
	rk_idx = smc_rtoken_add(link,
				llc->rtoken[0].rmb_vaddr,
				llc->rtoken[0].rmb_key);
	if (rk_idx < 0)
		goto out_err;

	for (i = 1; i <= min_t(u8, num_entries, SMC_LLC_RKEYS_PER_MSG - 1); i++)
		smc_rtoken_set2(lgr, rk_idx, llc->rtoken[i].link_id,
				llc->rtoken[i].rmb_vaddr,
				llc->rtoken[i].rmb_key);
	/* max links is 3 so there is no need to support conf_rkey_cont msgs */
	goto out;
out_err:
	llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
	llc->hd.flags |= SMC_LLC_FLAG_RKEY_RETRY;
out:
	llc->hd.flags |= SMC_LLC_FLAG_RESP;
	smc_llc_send_message(link, &qentry->msg);
	smc_llc_flow_qentry_del(&lgr->llc_flow_rmt);
}

/* process a delete_rkey request from peer, remote flow */
static void smc_llc_rmt_delete_rkey(struct smc_link_group *lgr)
{
	struct smc_llc_msg_delete_rkey *llc;
	struct smc_llc_qentry *qentry;
	struct smc_link *link;
	u8 err_mask = 0;
	int i, max;

	qentry = lgr->llc_flow_rmt.qentry;
	llc = &qentry->msg.delete_rkey;
	link = qentry->link;

	max = min_t(u8, llc->num_rkeys, SMC_LLC_DEL_RKEY_MAX);
	for (i = 0; i < max; i++) {
		if (smc_rtoken_delete(link, llc->rkey[i]))
			err_mask |= 1 << (SMC_LLC_DEL_RKEY_MAX - 1 - i);
	}
	if (err_mask) {
		llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
		llc->err_mask = err_mask;
	}
	llc->hd.flags |= SMC_LLC_FLAG_RESP;
	smc_llc_send_message(link, &qentry->msg);
	smc_llc_flow_qentry_del(&lgr->llc_flow_rmt);
}

static void smc_llc_protocol_violation(struct smc_link_group *lgr, u8 type)
{
	pr_warn_ratelimited("smc: SMC-R lg %*phN LLC protocol violation: "
			    "llc_type %d\n", SMC_LGR_ID_SIZE, &lgr->id, type);
	smc_llc_set_termination_rsn(lgr, SMC_LLC_DEL_PROT_VIOL);
	smc_lgr_terminate_sched(lgr);
}

/* flush the llc event queue */
static void smc_llc_event_flush(struct smc_link_group *lgr)
{
	struct smc_llc_qentry *qentry, *q;

	spin_lock_bh(&lgr->llc_event_q_lock);
	list_for_each_entry_safe(qentry, q, &lgr->llc_event_q, list) {
		list_del_init(&qentry->list);
		kfree(qentry);
	}
	spin_unlock_bh(&lgr->llc_event_q_lock);
}

static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
{
	union smc_llc_msg *llc = &qentry->msg;
	struct smc_link *link = qentry->link;
	struct smc_link_group *lgr = link->lgr;

	if (!smc_link_usable(link))
		goto out;

	switch (llc->raw.hdr.common.type) {
	case SMC_LLC_TEST_LINK:
		llc->test_link.hd.flags |= SMC_LLC_FLAG_RESP;
		smc_llc_send_message(link, llc);
		break;
	case SMC_LLC_ADD_LINK:
		if (list_empty(&lgr->list))
			goto out;	/* lgr is terminating */
		if (lgr->role == SMC_CLNT) {
			if (smc_llc_is_local_add_link(llc)) {
				if (lgr->llc_flow_lcl.type ==
				    SMC_LLC_FLOW_ADD_LINK)
					break;	/* add_link in progress */
				if (smc_llc_flow_start(&lgr->llc_flow_lcl,
						       qentry)) {
					schedule_work(&lgr->llc_add_link_work);
				}
				return;
			}
			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
			    !lgr->llc_flow_lcl.qentry) {
				/* a flow is waiting for this message */
				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
							qentry);
				wake_up(&lgr->llc_msg_waiter);
			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
						      qentry)) {
				schedule_work(&lgr->llc_add_link_work);
			}
		} else if (smc_llc_flow_start(&lgr->llc_flow_lcl, qentry)) {
			/* as smc server, handle client suggestion */
			schedule_work(&lgr->llc_add_link_work);
		}
		return;
	case SMC_LLC_CONFIRM_LINK:
	case SMC_LLC_ADD_LINK_CONT:
		if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) {
			/* a flow is waiting for this message */
			smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry);
			wake_up(&lgr->llc_msg_waiter);
			return;
		}
		break;
	case SMC_LLC_DELETE_LINK:
		if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
		    !lgr->llc_flow_lcl.qentry) {
			/* DEL LINK REQ during ADD LINK SEQ */
			smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry);
			wake_up(&lgr->llc_msg_waiter);
		} else if (smc_llc_flow_start(&lgr->llc_flow_lcl, qentry)) {
			schedule_work(&lgr->llc_del_link_work);
		}
		return;
	case SMC_LLC_CONFIRM_RKEY:
		/* new request from remote, assign to remote flow */
		if (smc_llc_flow_start(&lgr->llc_flow_rmt, qentry)) {
			/* process here, does not wait for more llc msgs */
			smc_llc_rmt_conf_rkey(lgr);
			smc_llc_flow_stop(lgr, &lgr->llc_flow_rmt);
		}
		return;
	case SMC_LLC_CONFIRM_RKEY_CONT:
		/* not used because max links is 3, and 3 rkeys fit into
		 * one CONFIRM_RKEY message
		 */
		break;
	case SMC_LLC_DELETE_RKEY:
		/* new request from remote, assign to remote flow */
		if (smc_llc_flow_start(&lgr->llc_flow_rmt, qentry)) {
			/* process here, does not wait for more llc msgs */
			smc_llc_rmt_delete_rkey(lgr);
			smc_llc_flow_stop(lgr, &lgr->llc_flow_rmt);
		}
		return;
	default:
		smc_llc_protocol_violation(lgr, llc->raw.hdr.common.type);
		break;
	}
out:
	kfree(qentry);
}

/* worker to process llc messages on the event queue */
static void smc_llc_event_work(struct work_struct *work)
{
	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
						  llc_event_work);
	struct smc_llc_qentry *qentry;

	if (!lgr->llc_flow_lcl.type && lgr->delayed_event) {
		if (smc_link_usable(lgr->delayed_event->link)) {
			smc_llc_event_handler(lgr->delayed_event);
		} else {
			qentry = lgr->delayed_event;
			lgr->delayed_event = NULL;
			kfree(qentry);
		}
	}

again:
	spin_lock_bh(&lgr->llc_event_q_lock);
	if (!list_empty(&lgr->llc_event_q)) {
		qentry = list_first_entry(&lgr->llc_event_q,
					  struct smc_llc_qentry, list);
		list_del_init(&qentry->list);
		spin_unlock_bh(&lgr->llc_event_q_lock);
		smc_llc_event_handler(qentry);
		goto again;
	}
	spin_unlock_bh(&lgr->llc_event_q_lock);
}

/* process llc responses in tasklet context */
static void smc_llc_rx_response(struct smc_link *link,
				struct smc_llc_qentry *qentry)
{
	enum smc_llc_flowtype flowtype = link->lgr->llc_flow_lcl.type;
	struct smc_llc_flow *flow = &link->lgr->llc_flow_lcl;
	u8 llc_type = qentry->msg.raw.hdr.common.type;

	switch (llc_type) {
	case SMC_LLC_TEST_LINK:
		if (link->state == SMC_LNK_ACTIVE)
			complete(&link->llc_testlink_resp);
		break;
	case SMC_LLC_ADD_LINK:
	case SMC_LLC_ADD_LINK_CONT:
	case SMC_LLC_CONFIRM_LINK:
		if (flowtype != SMC_LLC_FLOW_ADD_LINK || flow->qentry)
			break;	/* drop out-of-flow response */
		goto assign;
	case SMC_LLC_DELETE_LINK:
		if (flowtype != SMC_LLC_FLOW_DEL_LINK || flow->qentry)
			break;	/* drop out-of-flow response */
		goto assign;
	case SMC_LLC_CONFIRM_RKEY:
	case SMC_LLC_DELETE_RKEY:
		if (flowtype != SMC_LLC_FLOW_RKEY || flow->qentry)
			break;	/* drop out-of-flow response */
		goto assign;
	case SMC_LLC_CONFIRM_RKEY_CONT:
		/* not used because max links is 3 */
		break;
	default:
		smc_llc_protocol_violation(link->lgr, llc_type);
		break;
	}
	kfree(qentry);
	return;
assign:
	/* assign responses to the local flow, we requested them */
	smc_llc_flow_qentry_set(&link->lgr->llc_flow_lcl, qentry);
	wake_up(&link->lgr->llc_msg_waiter);
}

static void smc_llc_enqueue(struct smc_link *link, union smc_llc_msg *llc)
{
	struct smc_link_group *lgr = link->lgr;
	struct smc_llc_qentry *qentry;
	unsigned long flags;

	qentry = kmalloc(sizeof(*qentry), GFP_ATOMIC);
	if (!qentry)
		return;
	qentry->link = link;
	INIT_LIST_HEAD(&qentry->list);
	memcpy(&qentry->msg, llc, sizeof(union smc_llc_msg));

	/* process responses immediately */
	if (llc->raw.hdr.flags & SMC_LLC_FLAG_RESP) {
		smc_llc_rx_response(link, qentry);
		return;
	}

	/* add requests to event queue */
	spin_lock_irqsave(&lgr->llc_event_q_lock, flags);
	list_add_tail(&qentry->list, &lgr->llc_event_q);
	spin_unlock_irqrestore(&lgr->llc_event_q_lock, flags);
	schedule_work(&lgr->llc_event_work);
}

/* copy received msg and add it to the event queue */
static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
{
	struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
	union smc_llc_msg *llc = buf;

	if (wc->byte_len < sizeof(*llc))
		return; /* short message */
	if (llc->raw.hdr.length != sizeof(*llc))
		return; /* invalid message */

	smc_llc_enqueue(link, llc);
}

/***************************** worker, utils *********************************/

static void smc_llc_testlink_work(struct work_struct *work)
{
	struct smc_link *link = container_of(to_delayed_work(work),
					     struct smc_link, llc_testlink_wrk);
	unsigned long next_interval;
	unsigned long expire_time;
	u8 user_data[16] = { 0 };
	int rc;

	if (link->state != SMC_LNK_ACTIVE)
		return;		/* don't reschedule worker */
	expire_time = link->wr_rx_tstamp + link->llc_testlink_time;
	if (time_is_after_jiffies(expire_time)) {
		next_interval = expire_time - jiffies;
		goto out;
	}
	reinit_completion(&link->llc_testlink_resp);
	smc_llc_send_test_link(link, user_data);
	/* receive TEST LINK response over RoCE fabric */
	rc = wait_for_completion_interruptible_timeout(&link->llc_testlink_resp,
						       SMC_LLC_WAIT_TIME);
	if (link->state != SMC_LNK_ACTIVE)
		return;		/* link state changed */
	if (rc <= 0) {
		smcr_link_down_cond_sched(link);
		return;
	}
	next_interval = link->llc_testlink_time;
out:
	schedule_delayed_work(&link->llc_testlink_wrk, next_interval);
}

void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc)
{
	struct net *net = sock_net(smc->clcsock->sk);

	INIT_WORK(&lgr->llc_event_work, smc_llc_event_work);
	INIT_WORK(&lgr->llc_add_link_work, smc_llc_add_link_work);
	INIT_WORK(&lgr->llc_del_link_work, smc_llc_delete_link_work);
	INIT_LIST_HEAD(&lgr->llc_event_q);
	spin_lock_init(&lgr->llc_event_q_lock);
	spin_lock_init(&lgr->llc_flow_lock);
	init_waitqueue_head(&lgr->llc_flow_waiter);
	init_waitqueue_head(&lgr->llc_msg_waiter);
	mutex_init(&lgr->llc_conf_mutex);
	lgr->llc_testlink_time = net->ipv4.sysctl_tcp_keepalive_time;
}

/* called after lgr was removed from lgr_list */
void smc_llc_lgr_clear(struct smc_link_group *lgr)
{
	smc_llc_event_flush(lgr);
	wake_up_all(&lgr->llc_flow_waiter);
	wake_up_all(&lgr->llc_msg_waiter);
	cancel_work_sync(&lgr->llc_event_work);
	cancel_work_sync(&lgr->llc_add_link_work);
	cancel_work_sync(&lgr->llc_del_link_work);
	if (lgr->delayed_event) {
		kfree(lgr->delayed_event);
		lgr->delayed_event = NULL;
	}
}

int smc_llc_link_init(struct smc_link *link)
{
	init_completion(&link->llc_testlink_resp);
	INIT_DELAYED_WORK(&link->llc_testlink_wrk, smc_llc_testlink_work);
	return 0;
}

void smc_llc_link_active(struct smc_link *link)
{
	pr_warn_ratelimited("smc: SMC-R lg %*phN link added: id %*phN, "
			    "peerid %*phN, ibdev %s, ibport %d\n",
			    SMC_LGR_ID_SIZE, &link->lgr->id,
			    SMC_LGR_ID_SIZE, &link->link_uid,
			    SMC_LGR_ID_SIZE, &link->peer_link_uid,
			    link->smcibdev->ibdev->name, link->ibport);
	link->state = SMC_LNK_ACTIVE;
	if (link->lgr->llc_testlink_time) {
		link->llc_testlink_time = link->lgr->llc_testlink_time * HZ;
		schedule_delayed_work(&link->llc_testlink_wrk,
				      link->llc_testlink_time);
	}
}

/* called in worker context */
void smc_llc_link_clear(struct smc_link *link, bool log)
{
	if (log)
		pr_warn_ratelimited("smc: SMC-R lg %*phN link removed: id %*phN"
				    ", peerid %*phN, ibdev %s, ibport %d\n",
				    SMC_LGR_ID_SIZE, &link->lgr->id,
				    SMC_LGR_ID_SIZE, &link->link_uid,
				    SMC_LGR_ID_SIZE, &link->peer_link_uid,
				    link->smcibdev->ibdev->name, link->ibport);
	complete(&link->llc_testlink_resp);
	cancel_delayed_work_sync(&link->llc_testlink_wrk);
	smc_wr_wakeup_reg_wait(link);
	smc_wr_wakeup_tx_wait(link);
}

/* register a new rtoken at the remote peer (for all links) */
int smc_llc_do_confirm_rkey(struct smc_link *send_link,
			    struct smc_buf_desc *rmb_desc)
{
	struct smc_link_group *lgr = send_link->lgr;
	struct smc_llc_qentry *qentry = NULL;
	int rc = 0;

	rc = smc_llc_send_confirm_rkey(send_link, rmb_desc);
	if (rc)
		goto out;
	/* receive CONFIRM RKEY response from server over RoCE fabric */
	qentry = smc_llc_wait(lgr, send_link, SMC_LLC_WAIT_TIME,
			      SMC_LLC_CONFIRM_RKEY);
	if (!qentry || (qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_RKEY_NEG))
		rc = -EFAULT;
out:
	if (qentry)
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
	return rc;
}

/* unregister an rtoken at the remote peer */
int smc_llc_do_delete_rkey(struct smc_link_group *lgr,
			   struct smc_buf_desc *rmb_desc)
{
	struct smc_llc_qentry *qentry = NULL;
	struct smc_link *send_link;
	int rc = 0;

	send_link = smc_llc_usable_link(lgr);
	if (!send_link)
		return -ENOLINK;

	/* protected by llc_flow control */
	rc = smc_llc_send_delete_rkey(send_link, rmb_desc);
	if (rc)
		goto out;
	/* receive DELETE RKEY response from server over RoCE fabric */
	qentry = smc_llc_wait(lgr, send_link, SMC_LLC_WAIT_TIME,
			      SMC_LLC_DELETE_RKEY);
	if (!qentry || (qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_RKEY_NEG))
		rc = -EFAULT;
out:
	if (qentry)
		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
	return rc;
}

void smc_llc_link_set_uid(struct smc_link *link)
{
	__be32 link_uid;

	link_uid = htonl(*((u32 *)link->lgr->id) + link->link_id);
	memcpy(link->link_uid, &link_uid, SMC_LGR_ID_SIZE);
}

/* save peers link user id, used for debug purposes */
void smc_llc_save_peer_uid(struct smc_llc_qentry *qentry)
{
	memcpy(qentry->link->peer_link_uid, qentry->msg.confirm_link.link_uid,
	       SMC_LGR_ID_SIZE);
}

/* evaluate confirm link request or response */
int smc_llc_eval_conf_link(struct smc_llc_qentry *qentry,
			   enum smc_llc_reqresp type)
{
	if (type == SMC_LLC_REQ) {	/* SMC server assigns link_id */
		qentry->link->link_id = qentry->msg.confirm_link.link_num;
		smc_llc_link_set_uid(qentry->link);
	}
	if (!(qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
		return -ENOTSUPP;
	return 0;
}

/***************************** init, exit, misc ******************************/

static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_CONFIRM_LINK
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_TEST_LINK
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_ADD_LINK
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_ADD_LINK_CONT
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_DELETE_LINK
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_CONFIRM_RKEY
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_CONFIRM_RKEY_CONT
	},
	{
		.handler	= smc_llc_rx_handler,
		.type		= SMC_LLC_DELETE_RKEY
	},
	{
		.handler	= NULL,
	}
};

int __init smc_llc_init(void)
{
	struct smc_wr_rx_handler *handler;
	int rc = 0;

	for (handler = smc_llc_rx_handlers; handler->handler; handler++) {
		INIT_HLIST_NODE(&handler->list);
		rc = smc_wr_rx_register_handler(handler);
		if (rc)
			break;
	}
	return rc;
}