aboutsummaryrefslogtreecommitdiffstats
path: root/net/smc/smc_core.c
blob: bb92c7c6214c30d32dfaa38f3e97ae743c384d2c (plain) (blame)
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
// SPDX-License-Identifier: GPL-2.0
/*
 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  Basic Transport Functions exploiting Infiniband API
 *
 *  Copyright IBM Corp. 2016
 *
 *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <linux/socket.h>
#include <linux/if_vlan.h>
#include <linux/random.h>
#include <linux/workqueue.h>
#include <linux/wait.h>
#include <linux/reboot.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <rdma/ib_verbs.h>
#include <rdma/ib_cache.h>

#include "smc.h"
#include "smc_clc.h"
#include "smc_core.h"
#include "smc_ib.h"
#include "smc_wr.h"
#include "smc_llc.h"
#include "smc_cdc.h"
#include "smc_close.h"
#include "smc_ism.h"

#define SMC_LGR_NUM_INCR		256
#define SMC_LGR_FREE_DELAY_SERV		(600 * HZ)
#define SMC_LGR_FREE_DELAY_CLNT		(SMC_LGR_FREE_DELAY_SERV + 10 * HZ)
#define SMC_LGR_FREE_DELAY_FAST		(8 * HZ)

static struct smc_lgr_list smc_lgr_list = {	/* established link groups */
	.lock = __SPIN_LOCK_UNLOCKED(smc_lgr_list.lock),
	.list = LIST_HEAD_INIT(smc_lgr_list.list),
	.num = 0,
};

static atomic_t lgr_cnt;		/* number of existing link groups */
static DECLARE_WAIT_QUEUE_HEAD(lgrs_deleted);

static void smc_buf_free(struct smc_link_group *lgr, bool is_rmb,
			 struct smc_buf_desc *buf_desc);

/* return head of link group list and its lock for a given link group */
static inline struct list_head *smc_lgr_list_head(struct smc_link_group *lgr,
						  spinlock_t **lgr_lock)
{
	if (lgr->is_smcd) {
		*lgr_lock = &lgr->smcd->lgr_lock;
		return &lgr->smcd->lgr_list;
	}

	*lgr_lock = &smc_lgr_list.lock;
	return &smc_lgr_list.list;
}

static void smc_lgr_schedule_free_work(struct smc_link_group *lgr)
{
	/* client link group creation always follows the server link group
	 * creation. For client use a somewhat higher removal delay time,
	 * otherwise there is a risk of out-of-sync link groups.
	 */
	if (!lgr->freeing && !lgr->freefast) {
		mod_delayed_work(system_wq, &lgr->free_work,
				 (!lgr->is_smcd && lgr->role == SMC_CLNT) ?
						SMC_LGR_FREE_DELAY_CLNT :
						SMC_LGR_FREE_DELAY_SERV);
	}
}

void smc_lgr_schedule_free_work_fast(struct smc_link_group *lgr)
{
	if (!lgr->freeing && !lgr->freefast) {
		lgr->freefast = 1;
		mod_delayed_work(system_wq, &lgr->free_work,
				 SMC_LGR_FREE_DELAY_FAST);
	}
}

/* Register connection's alert token in our lookup structure.
 * To use rbtrees we have to implement our own insert core.
 * Requires @conns_lock
 * @smc		connection to register
 * Returns 0 on success, != otherwise.
 */
static void smc_lgr_add_alert_token(struct smc_connection *conn)
{
	struct rb_node **link, *parent = NULL;
	u32 token = conn->alert_token_local;

	link = &conn->lgr->conns_all.rb_node;
	while (*link) {
		struct smc_connection *cur = rb_entry(*link,
					struct smc_connection, alert_node);

		parent = *link;
		if (cur->alert_token_local > token)
			link = &parent->rb_left;
		else
			link = &parent->rb_right;
	}
	/* Put the new node there */
	rb_link_node(&conn->alert_node, parent, link);
	rb_insert_color(&conn->alert_node, &conn->lgr->conns_all);
}

/* Register connection in link group by assigning an alert token
 * registered in a search tree.
 * Requires @conns_lock
 * Note that '0' is a reserved value and not assigned.
 */
static void smc_lgr_register_conn(struct smc_connection *conn)
{
	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
	static atomic_t nexttoken = ATOMIC_INIT(0);

	/* find a new alert_token_local value not yet used by some connection
	 * in this link group
	 */
	sock_hold(&smc->sk); /* sock_put in smc_lgr_unregister_conn() */
	while (!conn->alert_token_local) {
		conn->alert_token_local = atomic_inc_return(&nexttoken);
		if (smc_lgr_find_conn(conn->alert_token_local, conn->lgr))
			conn->alert_token_local = 0;
	}
	smc_lgr_add_alert_token(conn);
	conn->lgr->conns_num++;
}

/* Unregister connection and reset the alert token of the given connection<
 */
static void __smc_lgr_unregister_conn(struct smc_connection *conn)
{
	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
	struct smc_link_group *lgr = conn->lgr;

	rb_erase(&conn->alert_node, &lgr->conns_all);
	lgr->conns_num--;
	conn->alert_token_local = 0;
	sock_put(&smc->sk); /* sock_hold in smc_lgr_register_conn() */
}

/* Unregister connection from lgr
 */
static void smc_lgr_unregister_conn(struct smc_connection *conn)
{
	struct smc_link_group *lgr = conn->lgr;

	if (!lgr)
		return;
	write_lock_bh(&lgr->conns_lock);
	if (conn->alert_token_local) {
		__smc_lgr_unregister_conn(conn);
	}
	write_unlock_bh(&lgr->conns_lock);
	conn->lgr = NULL;
}

/* Send delete link, either as client to request the initiation
 * of the DELETE LINK sequence from server; or as server to
 * initiate the delete processing. See smc_llc_rx_delete_link().
 */
static int smc_link_send_delete(struct smc_link *lnk, bool orderly)
{
	if (lnk->state == SMC_LNK_ACTIVE &&
	    !smc_llc_send_delete_link(lnk, SMC_LLC_REQ, orderly)) {
		smc_llc_link_deleting(lnk);
		return 0;
	}
	return -ENOTCONN;
}

static void smc_lgr_free(struct smc_link_group *lgr);

static void smc_lgr_free_work(struct work_struct *work)
{
	struct smc_link_group *lgr = container_of(to_delayed_work(work),
						  struct smc_link_group,
						  free_work);
	spinlock_t *lgr_lock;
	struct smc_link *lnk;
	bool conns;

	smc_lgr_list_head(lgr, &lgr_lock);
	spin_lock_bh(lgr_lock);
	if (lgr->freeing) {
		spin_unlock_bh(lgr_lock);
		return;
	}
	read_lock_bh(&lgr->conns_lock);
	conns = RB_EMPTY_ROOT(&lgr->conns_all);
	read_unlock_bh(&lgr->conns_lock);
	if (!conns) { /* number of lgr connections is no longer zero */
		spin_unlock_bh(lgr_lock);
		return;
	}
	list_del_init(&lgr->list); /* remove from smc_lgr_list */

	lnk = &lgr->lnk[SMC_SINGLE_LINK];
	if (!lgr->is_smcd && !lgr->terminating)	{
		/* try to send del link msg, on error free lgr immediately */
		if (lnk->state == SMC_LNK_ACTIVE &&
		    !smc_link_send_delete(lnk, true)) {
			/* reschedule in case we never receive a response */
			smc_lgr_schedule_free_work(lgr);
			spin_unlock_bh(lgr_lock);
			return;
		}
	}
	lgr->freeing = 1; /* this instance does the freeing, no new schedule */
	spin_unlock_bh(lgr_lock);
	cancel_delayed_work(&lgr->free_work);

	if (!lgr->is_smcd && lnk->state != SMC_LNK_INACTIVE)
		smc_llc_link_inactive(lnk);
	if (lgr->is_smcd && !lgr->terminating)
		smc_ism_signal_shutdown(lgr);
	smc_lgr_free(lgr);
}

static void smc_lgr_terminate_work(struct work_struct *work)
{
	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
						  terminate_work);

	smc_lgr_terminate(lgr, true);
}

/* create a new SMC link group */
static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
{
	struct smc_link_group *lgr;
	struct list_head *lgr_list;
	struct smc_link *lnk;
	spinlock_t *lgr_lock;
	u8 rndvec[3];
	int rc = 0;
	int i;

	if (ini->is_smcd && ini->vlan_id) {
		if (smc_ism_get_vlan(ini->ism_dev, ini->vlan_id)) {
			rc = SMC_CLC_DECL_ISMVLANERR;
			goto out;
		}
	}

	lgr = kzalloc(sizeof(*lgr), GFP_KERNEL);
	if (!lgr) {
		rc = SMC_CLC_DECL_MEM;
		goto ism_put_vlan;
	}
	lgr->is_smcd = ini->is_smcd;
	lgr->sync_err = 0;
	lgr->terminating = 0;
	lgr->freefast = 0;
	lgr->freeing = 0;
	lgr->vlan_id = ini->vlan_id;
	rwlock_init(&lgr->sndbufs_lock);
	rwlock_init(&lgr->rmbs_lock);
	rwlock_init(&lgr->conns_lock);
	for (i = 0; i < SMC_RMBE_SIZES; i++) {
		INIT_LIST_HEAD(&lgr->sndbufs[i]);
		INIT_LIST_HEAD(&lgr->rmbs[i]);
	}
	smc_lgr_list.num += SMC_LGR_NUM_INCR;
	memcpy(&lgr->id, (u8 *)&smc_lgr_list.num, SMC_LGR_ID_SIZE);
	INIT_DELAYED_WORK(&lgr->free_work, smc_lgr_free_work);
	INIT_WORK(&lgr->terminate_work, smc_lgr_terminate_work);
	lgr->conns_all = RB_ROOT;
	if (ini->is_smcd) {
		/* SMC-D specific settings */
		get_device(&ini->ism_dev->dev);
		lgr->peer_gid = ini->ism_gid;
		lgr->smcd = ini->ism_dev;
		lgr_list = &ini->ism_dev->lgr_list;
		lgr_lock = &lgr->smcd->lgr_lock;
		lgr->peer_shutdown = 0;
		atomic_inc(&ini->ism_dev->lgr_cnt);
	} else {
		/* SMC-R specific settings */
		get_device(&ini->ib_dev->ibdev->dev);
		lgr->role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
		memcpy(lgr->peer_systemid, ini->ib_lcl->id_for_peer,
		       SMC_SYSTEMID_LEN);

		lnk = &lgr->lnk[SMC_SINGLE_LINK];
		/* initialize link */
		lnk->state = SMC_LNK_ACTIVATING;
		lnk->link_id = SMC_SINGLE_LINK;
		lnk->smcibdev = ini->ib_dev;
		lnk->ibport = ini->ib_port;
		lgr_list = &smc_lgr_list.list;
		lgr_lock = &smc_lgr_list.lock;
		lnk->path_mtu =
			ini->ib_dev->pattr[ini->ib_port - 1].active_mtu;
		if (!ini->ib_dev->initialized)
			smc_ib_setup_per_ibdev(ini->ib_dev);
		get_random_bytes(rndvec, sizeof(rndvec));
		lnk->psn_initial = rndvec[0] + (rndvec[1] << 8) +
			(rndvec[2] << 16);
		rc = smc_ib_determine_gid(lnk->smcibdev, lnk->ibport,
					  ini->vlan_id, lnk->gid,
					  &lnk->sgid_index);
		if (rc)
			goto free_lgr;
		rc = smc_llc_link_init(lnk);
		if (rc)
			goto free_lgr;
		rc = smc_wr_alloc_link_mem(lnk);
		if (rc)
			goto clear_llc_lnk;
		rc = smc_ib_create_protection_domain(lnk);
		if (rc)
			goto free_link_mem;
		rc = smc_ib_create_queue_pair(lnk);
		if (rc)
			goto dealloc_pd;
		rc = smc_wr_create_link(lnk);
		if (rc)
			goto destroy_qp;
		atomic_inc(&lgr_cnt);
		atomic_inc(&ini->ib_dev->lnk_cnt);
	}
	smc->conn.lgr = lgr;
	spin_lock_bh(lgr_lock);
	list_add(&lgr->list, lgr_list);
	spin_unlock_bh(lgr_lock);
	return 0;

destroy_qp:
	smc_ib_destroy_queue_pair(lnk);
dealloc_pd:
	smc_ib_dealloc_protection_domain(lnk);
free_link_mem:
	smc_wr_free_link_mem(lnk);
clear_llc_lnk:
	smc_llc_link_clear(lnk);
free_lgr:
	kfree(lgr);
ism_put_vlan:
	if (ini->is_smcd && ini->vlan_id)
		smc_ism_put_vlan(ini->ism_dev, ini->vlan_id);
out:
	if (rc < 0) {
		if (rc == -ENOMEM)
			rc = SMC_CLC_DECL_MEM;
		else
			rc = SMC_CLC_DECL_INTERR;
	}
	return rc;
}

static void smc_buf_unuse(struct smc_connection *conn,
			  struct smc_link_group *lgr)
{
	if (conn->sndbuf_desc)
		conn->sndbuf_desc->used = 0;
	if (conn->rmb_desc) {
		if (!conn->rmb_desc->regerr) {
			if (!lgr->is_smcd && !list_empty(&lgr->list)) {
				/* unregister rmb with peer */
				smc_llc_do_delete_rkey(
						&lgr->lnk[SMC_SINGLE_LINK],
						conn->rmb_desc);
			}
			conn->rmb_desc->used = 0;
		} else {
			/* buf registration failed, reuse not possible */
			write_lock_bh(&lgr->rmbs_lock);
			list_del(&conn->rmb_desc->list);
			write_unlock_bh(&lgr->rmbs_lock);

			smc_buf_free(lgr, true, conn->rmb_desc);
		}
	}
}

/* remove a finished connection from its link group */
void smc_conn_free(struct smc_connection *conn)
{
	struct smc_link_group *lgr = conn->lgr;

	if (!lgr)
		return;
	if (lgr->is_smcd) {
		if (!list_empty(&lgr->list))
			smc_ism_unset_conn(conn);
		tasklet_kill(&conn->rx_tsklet);
	} else {
		smc_cdc_tx_dismiss_slots(conn);
	}
	if (!list_empty(&lgr->list)) {
		smc_lgr_unregister_conn(conn);
		smc_buf_unuse(conn, lgr); /* allow buffer reuse */
	}

	if (!lgr->conns_num)
		smc_lgr_schedule_free_work(lgr);
}

static void smc_link_clear(struct smc_link *lnk)
{
	lnk->peer_qpn = 0;
	smc_llc_link_clear(lnk);
	smc_ib_modify_qp_reset(lnk);
	smc_wr_free_link(lnk);
	smc_ib_destroy_queue_pair(lnk);
	smc_ib_dealloc_protection_domain(lnk);
	smc_wr_free_link_mem(lnk);
	if (!atomic_dec_return(&lnk->smcibdev->lnk_cnt))
		wake_up(&lnk->smcibdev->lnks_deleted);
}

static void smcr_buf_free(struct smc_link_group *lgr, bool is_rmb,
			  struct smc_buf_desc *buf_desc)
{
	struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];

	if (is_rmb) {
		if (buf_desc->mr_rx[SMC_SINGLE_LINK])
			smc_ib_put_memory_region(
					buf_desc->mr_rx[SMC_SINGLE_LINK]);
		smc_ib_buf_unmap_sg(lnk->smcibdev, buf_desc,
				    DMA_FROM_DEVICE);
	} else {
		smc_ib_buf_unmap_sg(lnk->smcibdev, buf_desc,
				    DMA_TO_DEVICE);
	}
	sg_free_table(&buf_desc->sgt[SMC_SINGLE_LINK]);
	if (buf_desc->pages)
		__free_pages(buf_desc->pages, buf_desc->order);
	kfree(buf_desc);
}

static void smcd_buf_free(struct smc_link_group *lgr, bool is_dmb,
			  struct smc_buf_desc *buf_desc)
{
	if (is_dmb) {
		/* restore original buf len */
		buf_desc->len += sizeof(struct smcd_cdc_msg);
		smc_ism_unregister_dmb(lgr->smcd, buf_desc);
	} else {
		kfree(buf_desc->cpu_addr);
	}
	kfree(buf_desc);
}

static void smc_buf_free(struct smc_link_group *lgr, bool is_rmb,
			 struct smc_buf_desc *buf_desc)
{
	if (lgr->is_smcd)
		smcd_buf_free(lgr, is_rmb, buf_desc);
	else
		smcr_buf_free(lgr, is_rmb, buf_desc);
}

static void __smc_lgr_free_bufs(struct smc_link_group *lgr, bool is_rmb)
{
	struct smc_buf_desc *buf_desc, *bf_desc;
	struct list_head *buf_list;
	int i;

	for (i = 0; i < SMC_RMBE_SIZES; i++) {
		if (is_rmb)
			buf_list = &lgr->rmbs[i];
		else
			buf_list = &lgr->sndbufs[i];
		list_for_each_entry_safe(buf_desc, bf_desc, buf_list,
					 list) {
			list_del(&buf_desc->list);
			smc_buf_free(lgr, is_rmb, buf_desc);
		}
	}
}

static void smc_lgr_free_bufs(struct smc_link_group *lgr)
{
	/* free send buffers */
	__smc_lgr_free_bufs(lgr, false);
	/* free rmbs */
	__smc_lgr_free_bufs(lgr, true);
}

/* remove a link group */
static void smc_lgr_free(struct smc_link_group *lgr)
{
	smc_lgr_free_bufs(lgr);
	if (lgr->is_smcd) {
		if (!lgr->terminating) {
			smc_ism_put_vlan(lgr->smcd, lgr->vlan_id);
			put_device(&lgr->smcd->dev);
		}
		if (!atomic_dec_return(&lgr->smcd->lgr_cnt))
			wake_up(&lgr->smcd->lgrs_deleted);
	} else {
		smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
		put_device(&lgr->lnk[SMC_SINGLE_LINK].smcibdev->ibdev->dev);
		if (!atomic_dec_return(&lgr_cnt))
			wake_up(&lgrs_deleted);
	}
	kfree(lgr);
}

void smc_lgr_forget(struct smc_link_group *lgr)
{
	struct list_head *lgr_list;
	spinlock_t *lgr_lock;

	lgr_list = smc_lgr_list_head(lgr, &lgr_lock);
	spin_lock_bh(lgr_lock);
	/* do not use this link group for new connections */
	if (!list_empty(lgr_list))
		list_del_init(lgr_list);
	spin_unlock_bh(lgr_lock);
}

static void smcd_unregister_all_dmbs(struct smc_link_group *lgr)
{
	int i;

	for (i = 0; i < SMC_RMBE_SIZES; i++) {
		struct smc_buf_desc *buf_desc;

		list_for_each_entry(buf_desc, &lgr->rmbs[i], list) {
			buf_desc->len += sizeof(struct smcd_cdc_msg);
			smc_ism_unregister_dmb(lgr->smcd, buf_desc);
		}
	}
}

static void smc_sk_wake_ups(struct smc_sock *smc)
{
	smc->sk.sk_write_space(&smc->sk);
	smc->sk.sk_data_ready(&smc->sk);
	smc->sk.sk_state_change(&smc->sk);
}

/* kill a connection */
static void smc_conn_kill(struct smc_connection *conn, bool soft)
{
	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);

	if (conn->lgr->is_smcd && conn->lgr->peer_shutdown)
		conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
	else
		smc_close_abort(conn);
	conn->killed = 1;
	smc->sk.sk_err = ECONNABORTED;
	smc_sk_wake_ups(smc);
	if (conn->lgr->is_smcd) {
		smc_ism_unset_conn(conn);
		if (soft)
			tasklet_kill(&conn->rx_tsklet);
		else
			tasklet_unlock_wait(&conn->rx_tsklet);
	} else {
		smc_cdc_tx_dismiss_slots(conn);
	}
	smc_lgr_unregister_conn(conn);
	smc_close_active_abort(smc);
}

static void smc_lgr_cleanup(struct smc_link_group *lgr)
{
	if (lgr->is_smcd) {
		smc_ism_signal_shutdown(lgr);
		smcd_unregister_all_dmbs(lgr);
		smc_ism_put_vlan(lgr->smcd, lgr->vlan_id);
		put_device(&lgr->smcd->dev);
	} else {
		struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];

		wake_up(&lnk->wr_reg_wait);
		if (lnk->state != SMC_LNK_INACTIVE) {
			smc_link_send_delete(lnk, false);
			smc_llc_link_inactive(lnk);
		}
	}
}

/* terminate link group */
static void __smc_lgr_terminate(struct smc_link_group *lgr, bool soft)
{
	struct smc_connection *conn;
	struct smc_sock *smc;
	struct rb_node *node;

	if (lgr->terminating)
		return;	/* lgr already terminating */
	if (!soft)
		cancel_delayed_work_sync(&lgr->free_work);
	lgr->terminating = 1;
	if (!lgr->is_smcd)
		smc_llc_link_inactive(&lgr->lnk[SMC_SINGLE_LINK]);

	/* kill remaining link group connections */
	read_lock_bh(&lgr->conns_lock);
	node = rb_first(&lgr->conns_all);
	while (node) {
		read_unlock_bh(&lgr->conns_lock);
		conn = rb_entry(node, struct smc_connection, alert_node);
		smc = container_of(conn, struct smc_sock, conn);
		sock_hold(&smc->sk); /* sock_put below */
		lock_sock(&smc->sk);
		smc_conn_kill(conn, soft);
		release_sock(&smc->sk);
		sock_put(&smc->sk); /* sock_hold above */
		read_lock_bh(&lgr->conns_lock);
		node = rb_first(&lgr->conns_all);
	}
	read_unlock_bh(&lgr->conns_lock);
	smc_lgr_cleanup(lgr);
	if (soft)
		smc_lgr_schedule_free_work_fast(lgr);
	else
		smc_lgr_free(lgr);
}

/* unlink and terminate link group
 * @soft: true if link group shutdown can take its time
 *	  false if immediate link group shutdown is required
 */
void smc_lgr_terminate(struct smc_link_group *lgr, bool soft)
{
	spinlock_t *lgr_lock;

	smc_lgr_list_head(lgr, &lgr_lock);
	spin_lock_bh(lgr_lock);
	if (lgr->terminating) {
		spin_unlock_bh(lgr_lock);
		return;	/* lgr already terminating */
	}
	if (!soft)
		lgr->freeing = 1;
	list_del_init(&lgr->list);
	spin_unlock_bh(lgr_lock);
	__smc_lgr_terminate(lgr, soft);
}

/* Called when IB port is terminated */
void smc_port_terminate(struct smc_ib_device *smcibdev, u8 ibport)
{
	struct smc_link_group *lgr, *l;
	LIST_HEAD(lgr_free_list);

	spin_lock_bh(&smc_lgr_list.lock);
	list_for_each_entry_safe(lgr, l, &smc_lgr_list.list, list) {
		if (!lgr->is_smcd &&
		    lgr->lnk[SMC_SINGLE_LINK].smcibdev == smcibdev &&
		    lgr->lnk[SMC_SINGLE_LINK].ibport == ibport) {
			list_move(&lgr->list, &lgr_free_list);
			lgr->freeing = 1;
		}
	}
	spin_unlock_bh(&smc_lgr_list.lock);

	list_for_each_entry_safe(lgr, l, &lgr_free_list, list) {
		list_del_init(&lgr->list);
		__smc_lgr_terminate(lgr, false);
	}
}

/* Called when peer lgr shutdown (regularly or abnormally) is received */
void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid, unsigned short vlan)
{
	struct smc_link_group *lgr, *l;
	LIST_HEAD(lgr_free_list);

	/* run common cleanup function and build free list */
	spin_lock_bh(&dev->lgr_lock);
	list_for_each_entry_safe(lgr, l, &dev->lgr_list, list) {
		if ((!peer_gid || lgr->peer_gid == peer_gid) &&
		    (vlan == VLAN_VID_MASK || lgr->vlan_id == vlan)) {
			if (peer_gid) /* peer triggered termination */
				lgr->peer_shutdown = 1;
			list_move(&lgr->list, &lgr_free_list);
		}
	}
	spin_unlock_bh(&dev->lgr_lock);

	/* cancel the regular free workers and actually free lgrs */
	list_for_each_entry_safe(lgr, l, &lgr_free_list, list) {
		list_del_init(&lgr->list);
		schedule_work(&lgr->terminate_work);
	}
}

/* Called when an SMCD device is removed or the smc module is unloaded */
void smc_smcd_terminate_all(struct smcd_dev *smcd)
{
	struct smc_link_group *lgr, *lg;
	LIST_HEAD(lgr_free_list);

	spin_lock_bh(&smcd->lgr_lock);
	list_splice_init(&smcd->lgr_list, &lgr_free_list);
	list_for_each_entry(lgr, &lgr_free_list, list)
		lgr->freeing = 1;
	spin_unlock_bh(&smcd->lgr_lock);

	list_for_each_entry_safe(lgr, lg, &lgr_free_list, list) {
		list_del_init(&lgr->list);
		__smc_lgr_terminate(lgr, false);
	}

	if (atomic_read(&smcd->lgr_cnt))
		wait_event(smcd->lgrs_deleted, !atomic_read(&smcd->lgr_cnt));
}

/* Called when an SMCR device is removed or the smc module is unloaded.
 * If smcibdev is given, all SMCR link groups using this device are terminated.
 * If smcibdev is NULL, all SMCR link groups are terminated.
 */
void smc_smcr_terminate_all(struct smc_ib_device *smcibdev)
{
	struct smc_link_group *lgr, *lg;
	LIST_HEAD(lgr_free_list);

	spin_lock_bh(&smc_lgr_list.lock);
	if (!smcibdev) {
		list_splice_init(&smc_lgr_list.list, &lgr_free_list);
		list_for_each_entry(lgr, &lgr_free_list, list)
			lgr->freeing = 1;
	} else {
		list_for_each_entry_safe(lgr, lg, &smc_lgr_list.list, list) {
			if (lgr->lnk[SMC_SINGLE_LINK].smcibdev == smcibdev) {
				list_move(&lgr->list, &lgr_free_list);
				lgr->freeing = 1;
			}
		}
	}
	spin_unlock_bh(&smc_lgr_list.lock);

	list_for_each_entry_safe(lgr, lg, &lgr_free_list, list) {
		list_del_init(&lgr->list);
		__smc_lgr_terminate(lgr, false);
	}

	if (smcibdev) {
		if (atomic_read(&smcibdev->lnk_cnt))
			wait_event(smcibdev->lnks_deleted,
				   !atomic_read(&smcibdev->lnk_cnt));
	} else {
		if (atomic_read(&lgr_cnt))
			wait_event(lgrs_deleted, !atomic_read(&lgr_cnt));
	}
}

/* Determine vlan of internal TCP socket.
 * @vlan_id: address to store the determined vlan id into
 */
int smc_vlan_by_tcpsk(struct socket *clcsock, struct smc_init_info *ini)
{
	struct dst_entry *dst = sk_dst_get(clcsock->sk);
	struct net_device *ndev;
	int i, nest_lvl, rc = 0;

	ini->vlan_id = 0;
	if (!dst) {
		rc = -ENOTCONN;
		goto out;
	}
	if (!dst->dev) {
		rc = -ENODEV;
		goto out_rel;
	}

	ndev = dst->dev;
	if (is_vlan_dev(ndev)) {
		ini->vlan_id = vlan_dev_vlan_id(ndev);
		goto out_rel;
	}

	rtnl_lock();
	nest_lvl = ndev->lower_level;
	for (i = 0; i < nest_lvl; i++) {
		struct list_head *lower = &ndev->adj_list.lower;

		if (list_empty(lower))
			break;
		lower = lower->next;
		ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower);
		if (is_vlan_dev(ndev)) {
			ini->vlan_id = vlan_dev_vlan_id(ndev);
			break;
		}
	}
	rtnl_unlock();

out_rel:
	dst_release(dst);
out:
	return rc;
}

static bool smcr_lgr_match(struct smc_link_group *lgr,
			   struct smc_clc_msg_local *lcl,
			   enum smc_lgr_role role, u32 clcqpn)
{
	return !memcmp(lgr->peer_systemid, lcl->id_for_peer,
		       SMC_SYSTEMID_LEN) &&
		!memcmp(lgr->lnk[SMC_SINGLE_LINK].peer_gid, &lcl->gid,
			SMC_GID_SIZE) &&
		!memcmp(lgr->lnk[SMC_SINGLE_LINK].peer_mac, lcl->mac,
			sizeof(lcl->mac)) &&
		lgr->role == role &&
		(lgr->role == SMC_SERV ||
		 lgr->lnk[SMC_SINGLE_LINK].peer_qpn == clcqpn);
}

static bool smcd_lgr_match(struct smc_link_group *lgr,
			   struct smcd_dev *smcismdev, u64 peer_gid)
{
	return lgr->peer_gid == peer_gid && lgr->smcd == smcismdev;
}

/* create a new SMC connection (and a new link group if necessary) */
int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
{
	struct smc_connection *conn = &smc->conn;
	struct list_head *lgr_list;
	struct smc_link_group *lgr;
	enum smc_lgr_role role;
	spinlock_t *lgr_lock;
	int rc = 0;

	lgr_list = ini->is_smcd ? &ini->ism_dev->lgr_list : &smc_lgr_list.list;
	lgr_lock = ini->is_smcd ? &ini->ism_dev->lgr_lock : &smc_lgr_list.lock;
	ini->cln_first_contact = SMC_FIRST_CONTACT;
	role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
	if (role == SMC_CLNT && ini->srv_first_contact)
		/* create new link group as well */
		goto create;

	/* determine if an existing link group can be reused */
	spin_lock_bh(lgr_lock);
	list_for_each_entry(lgr, lgr_list, list) {
		write_lock_bh(&lgr->conns_lock);
		if ((ini->is_smcd ?
		     smcd_lgr_match(lgr, ini->ism_dev, ini->ism_gid) :
		     smcr_lgr_match(lgr, ini->ib_lcl, role, ini->ib_clcqpn)) &&
		    !lgr->sync_err &&
		    lgr->vlan_id == ini->vlan_id &&
		    (role == SMC_CLNT ||
		     lgr->conns_num < SMC_RMBS_PER_LGR_MAX)) {
			/* link group found */
			ini->cln_first_contact = SMC_REUSE_CONTACT;
			conn->lgr = lgr;
			smc_lgr_register_conn(conn); /* add smc conn to lgr */
			if (delayed_work_pending(&lgr->free_work))
				cancel_delayed_work(&lgr->free_work);
			write_unlock_bh(&lgr->conns_lock);
			break;
		}
		write_unlock_bh(&lgr->conns_lock);
	}
	spin_unlock_bh(lgr_lock);

	if (role == SMC_CLNT && !ini->srv_first_contact &&
	    ini->cln_first_contact == SMC_FIRST_CONTACT) {
		/* Server reuses a link group, but Client wants to start
		 * a new one
		 * send out_of_sync decline, reason synchr. error
		 */
		return SMC_CLC_DECL_SYNCERR;
	}

create:
	if (ini->cln_first_contact == SMC_FIRST_CONTACT) {
		rc = smc_lgr_create(smc, ini);
		if (rc)
			goto out;
		lgr = conn->lgr;
		write_lock_bh(&lgr->conns_lock);
		smc_lgr_register_conn(conn); /* add smc conn to lgr */
		write_unlock_bh(&lgr->conns_lock);
	}
	conn->local_tx_ctrl.common.type = SMC_CDC_MSG_TYPE;
	conn->local_tx_ctrl.len = SMC_WR_TX_SIZE;
	conn->urg_state = SMC_URG_READ;
	if (ini->is_smcd) {
		conn->rx_off = sizeof(struct smcd_cdc_msg);
		smcd_cdc_rx_init(conn); /* init tasklet for this conn */
	}
#ifndef KERNEL_HAS_ATOMIC64
	spin_lock_init(&conn->acurs_lock);
#endif

out:
	return rc;
}

/* convert the RMB size into the compressed notation - minimum 16K.
 * In contrast to plain ilog2, this rounds towards the next power of 2,
 * so the socket application gets at least its desired sndbuf / rcvbuf size.
 */
static u8 smc_compress_bufsize(int size)
{
	u8 compressed;

	if (size <= SMC_BUF_MIN_SIZE)
		return 0;

	size = (size - 1) >> 14;
	compressed = ilog2(size) + 1;
	if (compressed >= SMC_RMBE_SIZES)
		compressed = SMC_RMBE_SIZES - 1;
	return compressed;
}

/* convert the RMB size from compressed notation into integer */
int smc_uncompress_bufsize(u8 compressed)
{
	u32 size;

	size = 0x00000001 << (((int)compressed) + 14);
	return (int)size;
}

/* try to reuse a sndbuf or rmb description slot for a certain
 * buffer size; if not available, return NULL
 */
static struct smc_buf_desc *smc_buf_get_slot(int compressed_bufsize,
					     rwlock_t *lock,
					     struct list_head *buf_list)
{
	struct smc_buf_desc *buf_slot;

	read_lock_bh(lock);
	list_for_each_entry(buf_slot, buf_list, list) {
		if (cmpxchg(&buf_slot->used, 0, 1) == 0) {
			read_unlock_bh(lock);
			return buf_slot;
		}
	}
	read_unlock_bh(lock);
	return NULL;
}

/* one of the conditions for announcing a receiver's current window size is
 * that it "results in a minimum increase in the window size of 10% of the
 * receive buffer space" [RFC7609]
 */
static inline int smc_rmb_wnd_update_limit(int rmbe_size)
{
	return min_t(int, rmbe_size / 10, SOCK_MIN_SNDBUF / 2);
}

static struct smc_buf_desc *smcr_new_buf_create(struct smc_link_group *lgr,
						bool is_rmb, int bufsize)
{
	struct smc_buf_desc *buf_desc;
	struct smc_link *lnk;
	int rc;

	/* try to alloc a new buffer */
	buf_desc = kzalloc(sizeof(*buf_desc), GFP_KERNEL);
	if (!buf_desc)
		return ERR_PTR(-ENOMEM);

	buf_desc->order = get_order(bufsize);
	buf_desc->pages = alloc_pages(GFP_KERNEL | __GFP_NOWARN |
				      __GFP_NOMEMALLOC | __GFP_COMP |
				      __GFP_NORETRY | __GFP_ZERO,
				      buf_desc->order);
	if (!buf_desc->pages) {
		kfree(buf_desc);
		return ERR_PTR(-EAGAIN);
	}
	buf_desc->cpu_addr = (void *)page_address(buf_desc->pages);

	/* build the sg table from the pages */
	lnk = &lgr->lnk[SMC_SINGLE_LINK];
	rc = sg_alloc_table(&buf_desc->sgt[SMC_SINGLE_LINK], 1,
			    GFP_KERNEL);
	if (rc) {
		smc_buf_free(lgr, is_rmb, buf_desc);
		return ERR_PTR(rc);
	}
	sg_set_buf(buf_desc->sgt[SMC_SINGLE_LINK].sgl,
		   buf_desc->cpu_addr, bufsize);

	/* map sg table to DMA address */
	rc = smc_ib_buf_map_sg(lnk->smcibdev, buf_desc,
			       is_rmb ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
	/* SMC protocol depends on mapping to one DMA address only */
	if (rc != 1)  {
		smc_buf_free(lgr, is_rmb, buf_desc);
		return ERR_PTR(-EAGAIN);
	}

	/* create a new memory region for the RMB */
	if (is_rmb) {
		rc = smc_ib_get_memory_region(lnk->roce_pd,
					      IB_ACCESS_REMOTE_WRITE |
					      IB_ACCESS_LOCAL_WRITE,
					      buf_desc);
		if (rc) {
			smc_buf_free(lgr, is_rmb, buf_desc);
			return ERR_PTR(rc);
		}
	}

	buf_desc->len = bufsize;
	return buf_desc;
}

#define SMCD_DMBE_SIZES		7 /* 0 -> 16KB, 1 -> 32KB, .. 6 -> 1MB */

static struct smc_buf_desc *smcd_new_buf_create(struct smc_link_group *lgr,
						bool is_dmb, int bufsize)
{
	struct smc_buf_desc *buf_desc;
	int rc;

	if (smc_compress_bufsize(bufsize) > SMCD_DMBE_SIZES)
		return ERR_PTR(-EAGAIN);

	/* try to alloc a new DMB */
	buf_desc = kzalloc(sizeof(*buf_desc), GFP_KERNEL);
	if (!buf_desc)
		return ERR_PTR(-ENOMEM);
	if (is_dmb) {
		rc = smc_ism_register_dmb(lgr, bufsize, buf_desc);
		if (rc) {
			kfree(buf_desc);
			return ERR_PTR(-EAGAIN);
		}
		buf_desc->pages = virt_to_page(buf_desc->cpu_addr);
		/* CDC header stored in buf. So, pretend it was smaller */
		buf_desc->len = bufsize - sizeof(struct smcd_cdc_msg);
	} else {
		buf_desc->cpu_addr = kzalloc(bufsize, GFP_KERNEL |
					     __GFP_NOWARN | __GFP_NORETRY |
					     __GFP_NOMEMALLOC);
		if (!buf_desc->cpu_addr) {
			kfree(buf_desc);
			return ERR_PTR(-EAGAIN);
		}
		buf_desc->len = bufsize;
	}
	return buf_desc;
}

static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
{
	struct smc_buf_desc *buf_desc = ERR_PTR(-ENOMEM);
	struct smc_connection *conn = &smc->conn;
	struct smc_link_group *lgr = conn->lgr;
	struct list_head *buf_list;
	int bufsize, bufsize_short;
	int sk_buf_size;
	rwlock_t *lock;

	if (is_rmb)
		/* use socket recv buffer size (w/o overhead) as start value */
		sk_buf_size = smc->sk.sk_rcvbuf / 2;
	else
		/* use socket send buffer size (w/o overhead) as start value */
		sk_buf_size = smc->sk.sk_sndbuf / 2;

	for (bufsize_short = smc_compress_bufsize(sk_buf_size);
	     bufsize_short >= 0; bufsize_short--) {

		if (is_rmb) {
			lock = &lgr->rmbs_lock;
			buf_list = &lgr->rmbs[bufsize_short];
		} else {
			lock = &lgr->sndbufs_lock;
			buf_list = &lgr->sndbufs[bufsize_short];
		}
		bufsize = smc_uncompress_bufsize(bufsize_short);
		if ((1 << get_order(bufsize)) > SG_MAX_SINGLE_ALLOC)
			continue;

		/* check for reusable slot in the link group */
		buf_desc = smc_buf_get_slot(bufsize_short, lock, buf_list);
		if (buf_desc) {
			memset(buf_desc->cpu_addr, 0, bufsize);
			break; /* found reusable slot */
		}

		if (is_smcd)
			buf_desc = smcd_new_buf_create(lgr, is_rmb, bufsize);
		else
			buf_desc = smcr_new_buf_create(lgr, is_rmb, bufsize);

		if (PTR_ERR(buf_desc) == -ENOMEM)
			break;
		if (IS_ERR(buf_desc))
			continue;

		buf_desc->used = 1;
		write_lock_bh(lock);
		list_add(&buf_desc->list, buf_list);
		write_unlock_bh(lock);
		break; /* found */
	}

	if (IS_ERR(buf_desc))
		return -ENOMEM;

	if (is_rmb) {
		conn->rmb_desc = buf_desc;
		conn->rmbe_size_short = bufsize_short;
		smc->sk.sk_rcvbuf = bufsize * 2;
		atomic_set(&conn->bytes_to_rcv, 0);
		conn->rmbe_update_limit =
			smc_rmb_wnd_update_limit(buf_desc->len);
		if (is_smcd)
			smc_ism_set_conn(conn); /* map RMB/smcd_dev to conn */
	} else {
		conn->sndbuf_desc = buf_desc;
		smc->sk.sk_sndbuf = bufsize * 2;
		atomic_set(&conn->sndbuf_space, bufsize);
	}
	return 0;
}

void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn)
{
	struct smc_link_group *lgr = conn->lgr;

	if (!conn->lgr || conn->lgr->is_smcd)
		return;
	smc_ib_sync_sg_for_cpu(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
			       conn->sndbuf_desc, DMA_TO_DEVICE);
}

void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn)
{
	struct smc_link_group *lgr = conn->lgr;

	if (!conn->lgr || conn->lgr->is_smcd)
		return;
	smc_ib_sync_sg_for_device(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
				  conn->sndbuf_desc, DMA_TO_DEVICE);
}

void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn)
{
	struct smc_link_group *lgr = conn->lgr;

	if (!conn->lgr || conn->lgr->is_smcd)
		return;
	smc_ib_sync_sg_for_cpu(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
			       conn->rmb_desc, DMA_FROM_DEVICE);
}

void smc_rmb_sync_sg_for_device(struct smc_connection *conn)
{
	struct smc_link_group *lgr = conn->lgr;

	if (!conn->lgr || conn->lgr->is_smcd)
		return;
	smc_ib_sync_sg_for_device(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
				  conn->rmb_desc, DMA_FROM_DEVICE);
}

/* create the send and receive buffer for an SMC socket;
 * receive buffers are called RMBs;
 * (even though the SMC protocol allows more than one RMB-element per RMB,
 * the Linux implementation uses just one RMB-element per RMB, i.e. uses an
 * extra RMB for every connection in a link group
 */
int smc_buf_create(struct smc_sock *smc, bool is_smcd)
{
	int rc;

	/* create send buffer */
	rc = __smc_buf_create(smc, is_smcd, false);
	if (rc)
		return rc;
	/* create rmb */
	rc = __smc_buf_create(smc, is_smcd, true);
	if (rc)
		smc_buf_free(smc->conn.lgr, false, smc->conn.sndbuf_desc);
	return rc;
}

static inline int smc_rmb_reserve_rtoken_idx(struct smc_link_group *lgr)
{
	int i;

	for_each_clear_bit(i, lgr->rtokens_used_mask, SMC_RMBS_PER_LGR_MAX) {
		if (!test_and_set_bit(i, lgr->rtokens_used_mask))
			return i;
	}
	return -ENOSPC;
}

/* add a new rtoken from peer */
int smc_rtoken_add(struct smc_link_group *lgr, __be64 nw_vaddr, __be32 nw_rkey)
{
	u64 dma_addr = be64_to_cpu(nw_vaddr);
	u32 rkey = ntohl(nw_rkey);
	int i;

	for (i = 0; i < SMC_RMBS_PER_LGR_MAX; i++) {
		if ((lgr->rtokens[i][SMC_SINGLE_LINK].rkey == rkey) &&
		    (lgr->rtokens[i][SMC_SINGLE_LINK].dma_addr == dma_addr) &&
		    test_bit(i, lgr->rtokens_used_mask)) {
			/* already in list */
			return i;
		}
	}
	i = smc_rmb_reserve_rtoken_idx(lgr);
	if (i < 0)
		return i;
	lgr->rtokens[i][SMC_SINGLE_LINK].rkey = rkey;
	lgr->rtokens[i][SMC_SINGLE_LINK].dma_addr = dma_addr;
	return i;
}

/* delete an rtoken */
int smc_rtoken_delete(struct smc_link_group *lgr, __be32 nw_rkey)
{
	u32 rkey = ntohl(nw_rkey);
	int i;

	for (i = 0; i < SMC_RMBS_PER_LGR_MAX; i++) {
		if (lgr->rtokens[i][SMC_SINGLE_LINK].rkey == rkey &&
		    test_bit(i, lgr->rtokens_used_mask)) {
			lgr->rtokens[i][SMC_SINGLE_LINK].rkey = 0;
			lgr->rtokens[i][SMC_SINGLE_LINK].dma_addr = 0;

			clear_bit(i, lgr->rtokens_used_mask);
			return 0;
		}
	}
	return -ENOENT;
}

/* save rkey and dma_addr received from peer during clc handshake */
int smc_rmb_rtoken_handling(struct smc_connection *conn,
			    struct smc_clc_msg_accept_confirm *clc)
{
	conn->rtoken_idx = smc_rtoken_add(conn->lgr, clc->rmb_dma_addr,
					  clc->rmb_rkey);
	if (conn->rtoken_idx < 0)
		return conn->rtoken_idx;
	return 0;
}

static void smc_core_going_away(void)
{
	struct smc_ib_device *smcibdev;
	struct smcd_dev *smcd;

	spin_lock(&smc_ib_devices.lock);
	list_for_each_entry(smcibdev, &smc_ib_devices.list, list) {
		int i;

		for (i = 0; i < SMC_MAX_PORTS; i++)
			set_bit(i, smcibdev->ports_going_away);
	}
	spin_unlock(&smc_ib_devices.lock);

	spin_lock(&smcd_dev_list.lock);
	list_for_each_entry(smcd, &smcd_dev_list.list, list) {
		smcd->going_away = 1;
	}
	spin_unlock(&smcd_dev_list.lock);
}

/* Clean up all SMC link groups */
static void smc_lgrs_shutdown(void)
{
	struct smcd_dev *smcd;

	smc_core_going_away();

	smc_smcr_terminate_all(NULL);

	spin_lock(&smcd_dev_list.lock);
	list_for_each_entry(smcd, &smcd_dev_list.list, list)
		smc_smcd_terminate_all(smcd);
	spin_unlock(&smcd_dev_list.lock);
}

static int smc_core_reboot_event(struct notifier_block *this,
				 unsigned long event, void *ptr)
{
	smc_lgrs_shutdown();

	return 0;
}

static struct notifier_block smc_reboot_notifier = {
	.notifier_call = smc_core_reboot_event,
};

int __init smc_core_init(void)
{
	atomic_set(&lgr_cnt, 0);
	return register_reboot_notifier(&smc_reboot_notifier);
}

/* Called (from smc_exit) when module is removed */
void smc_core_exit(void)
{
	unregister_reboot_notifier(&smc_reboot_notifier);
	smc_lgrs_shutdown();
}