aboutsummaryrefslogtreecommitdiff
path: root/net/sunrpc/xprtrdma/svc_rdma_transport.c
blob: edea15a54e51d90d03b0149e6602f38017743758 (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
/*
 * Copyright (c) 2005-2007 Network Appliance, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the BSD-type
 * license below:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *      Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 *      Neither the name of the Network Appliance, Inc. nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Author: Tom Tucker <tom@opengridcomputing.com>
 */

#include <linux/sunrpc/svc_xprt.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <linux/sunrpc/svc_rdma.h>

#define RPCDBG_FACILITY	RPCDBG_SVCXPRT

static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
					struct sockaddr *sa, int salen,
					int flags);
static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
static void svc_rdma_release_rqst(struct svc_rqst *);
static void dto_tasklet_func(unsigned long data);
static void svc_rdma_detach(struct svc_xprt *xprt);
static void svc_rdma_free(struct svc_xprt *xprt);
static int svc_rdma_has_wspace(struct svc_xprt *xprt);
static void rq_cq_reap(struct svcxprt_rdma *xprt);
static void sq_cq_reap(struct svcxprt_rdma *xprt);

static DECLARE_TASKLET(dto_tasklet, dto_tasklet_func, 0UL);
static DEFINE_SPINLOCK(dto_lock);
static LIST_HEAD(dto_xprt_q);

static struct svc_xprt_ops svc_rdma_ops = {
	.xpo_create = svc_rdma_create,
	.xpo_recvfrom = svc_rdma_recvfrom,
	.xpo_sendto = svc_rdma_sendto,
	.xpo_release_rqst = svc_rdma_release_rqst,
	.xpo_detach = svc_rdma_detach,
	.xpo_free = svc_rdma_free,
	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
	.xpo_has_wspace = svc_rdma_has_wspace,
	.xpo_accept = svc_rdma_accept,
};

struct svc_xprt_class svc_rdma_class = {
	.xcl_name = "rdma",
	.xcl_owner = THIS_MODULE,
	.xcl_ops = &svc_rdma_ops,
	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
};

/* WR context cache. Created in svc_rdma.c  */
extern struct kmem_cache *svc_rdma_ctxt_cachep;

struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
{
	struct svc_rdma_op_ctxt *ctxt;

	while (1) {
		ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep, GFP_KERNEL);
		if (ctxt)
			break;
		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
	}
	ctxt->xprt = xprt;
	INIT_LIST_HEAD(&ctxt->dto_q);
	ctxt->count = 0;
	ctxt->frmr = NULL;
	atomic_inc(&xprt->sc_ctxt_used);
	return ctxt;
}

void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
{
	struct svcxprt_rdma *xprt = ctxt->xprt;
	int i;
	for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
		/*
		 * Unmap the DMA addr in the SGE if the lkey matches
		 * the sc_dma_lkey, otherwise, ignore it since it is
		 * an FRMR lkey and will be unmapped later when the
		 * last WR that uses it completes.
		 */
		if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
			atomic_dec(&xprt->sc_dma_used);
			ib_dma_unmap_single(xprt->sc_cm_id->device,
					    ctxt->sge[i].addr,
					    ctxt->sge[i].length,
					    ctxt->direction);
		}
	}
}

void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
{
	struct svcxprt_rdma *xprt;
	int i;

	BUG_ON(!ctxt);
	xprt = ctxt->xprt;
	if (free_pages)
		for (i = 0; i < ctxt->count; i++)
			put_page(ctxt->pages[i]);

	kmem_cache_free(svc_rdma_ctxt_cachep, ctxt);
	atomic_dec(&xprt->sc_ctxt_used);
}

/* Temporary NFS request map cache. Created in svc_rdma.c  */
extern struct kmem_cache *svc_rdma_map_cachep;

/*
 * Temporary NFS req mappings are shared across all transport
 * instances. These are short lived and should be bounded by the number
 * of concurrent server threads * depth of the SQ.
 */
struct svc_rdma_req_map *svc_rdma_get_req_map(void)
{
	struct svc_rdma_req_map *map;
	while (1) {
		map = kmem_cache_alloc(svc_rdma_map_cachep, GFP_KERNEL);
		if (map)
			break;
		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
	}
	map->count = 0;
	map->frmr = NULL;
	return map;
}

void svc_rdma_put_req_map(struct svc_rdma_req_map *map)
{
	kmem_cache_free(svc_rdma_map_cachep, map);
}

/* ib_cq event handler */
static void cq_event_handler(struct ib_event *event, void *context)
{
	struct svc_xprt *xprt = context;
	dprintk("svcrdma: received CQ event id=%d, context=%p\n",
		event->event, context);
	set_bit(XPT_CLOSE, &xprt->xpt_flags);
}

/* QP event handler */
static void qp_event_handler(struct ib_event *event, void *context)
{
	struct svc_xprt *xprt = context;

	switch (event->event) {
	/* These are considered benign events */
	case IB_EVENT_PATH_MIG:
	case IB_EVENT_COMM_EST:
	case IB_EVENT_SQ_DRAINED:
	case IB_EVENT_QP_LAST_WQE_REACHED:
		dprintk("svcrdma: QP event %d received for QP=%p\n",
			event->event, event->element.qp);
		break;
	/* These are considered fatal events */
	case IB_EVENT_PATH_MIG_ERR:
	case IB_EVENT_QP_FATAL:
	case IB_EVENT_QP_REQ_ERR:
	case IB_EVENT_QP_ACCESS_ERR:
	case IB_EVENT_DEVICE_FATAL:
	default:
		dprintk("svcrdma: QP ERROR event %d received for QP=%p, "
			"closing transport\n",
			event->event, event->element.qp);
		set_bit(XPT_CLOSE, &xprt->xpt_flags);
		break;
	}
}

/*
 * Data Transfer Operation Tasklet
 *
 * Walks a list of transports with I/O pending, removing entries as
 * they are added to the server's I/O pending list. Two bits indicate
 * if SQ, RQ, or both have I/O pending. The dto_lock is an irqsave
 * spinlock that serializes access to the transport list with the RQ
 * and SQ interrupt handlers.
 */
static void dto_tasklet_func(unsigned long data)
{
	struct svcxprt_rdma *xprt;
	unsigned long flags;

	spin_lock_irqsave(&dto_lock, flags);
	while (!list_empty(&dto_xprt_q)) {
		xprt = list_entry(dto_xprt_q.next,
				  struct svcxprt_rdma, sc_dto_q);
		list_del_init(&xprt->sc_dto_q);
		spin_unlock_irqrestore(&dto_lock, flags);

		rq_cq_reap(xprt);
		sq_cq_reap(xprt);

		svc_xprt_put(&xprt->sc_xprt);
		spin_lock_irqsave(&dto_lock, flags);
	}
	spin_unlock_irqrestore(&dto_lock, flags);
}

/*
 * Receive Queue Completion Handler
 *
 * Since an RQ completion handler is called on interrupt context, we
 * need to defer the handling of the I/O to a tasklet
 */
static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
{
	struct svcxprt_rdma *xprt = cq_context;
	unsigned long flags;

	/* Guard against unconditional flush call for destroyed QP */
	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
		return;

	/*
	 * Set the bit regardless of whether or not it's on the list
	 * because it may be on the list already due to an SQ
	 * completion.
	 */
	set_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags);

	/*
	 * If this transport is not already on the DTO transport queue,
	 * add it
	 */
	spin_lock_irqsave(&dto_lock, flags);
	if (list_empty(&xprt->sc_dto_q)) {
		svc_xprt_get(&xprt->sc_xprt);
		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
	}
	spin_unlock_irqrestore(&dto_lock, flags);

	/* Tasklet does all the work to avoid irqsave locks. */
	tasklet_schedule(&dto_tasklet);
}

/*
 * rq_cq_reap - Process the RQ CQ.
 *
 * Take all completing WC off the CQE and enqueue the associated DTO
 * context on the dto_q for the transport.
 *
 * Note that caller must hold a transport reference.
 */
static void rq_cq_reap(struct svcxprt_rdma *xprt)
{
	int ret;
	struct ib_wc wc;
	struct svc_rdma_op_ctxt *ctxt = NULL;

	if (!test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags))
		return;

	ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
	atomic_inc(&rdma_stat_rq_poll);

	while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
		ctxt->wc_status = wc.status;
		ctxt->byte_len = wc.byte_len;
		svc_rdma_unmap_dma(ctxt);
		if (wc.status != IB_WC_SUCCESS) {
			/* Close the transport */
			dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
			svc_rdma_put_context(ctxt, 1);
			svc_xprt_put(&xprt->sc_xprt);
			continue;
		}
		spin_lock_bh(&xprt->sc_rq_dto_lock);
		list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
		spin_unlock_bh(&xprt->sc_rq_dto_lock);
		svc_xprt_put(&xprt->sc_xprt);
	}

	if (ctxt)
		atomic_inc(&rdma_stat_rq_prod);

	set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
	/*
	 * If data arrived before established event,
	 * don't enqueue. This defers RPC I/O until the
	 * RDMA connection is complete.
	 */
	if (!test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
		svc_xprt_enqueue(&xprt->sc_xprt);
}

/*
 * Processs a completion context
 */
static void process_context(struct svcxprt_rdma *xprt,
			    struct svc_rdma_op_ctxt *ctxt)
{
	svc_rdma_unmap_dma(ctxt);

	switch (ctxt->wr_op) {
	case IB_WR_SEND:
		if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
			svc_rdma_put_frmr(xprt, ctxt->frmr);
		svc_rdma_put_context(ctxt, 1);
		break;

	case IB_WR_RDMA_WRITE:
		svc_rdma_put_context(ctxt, 0);
		break;

	case IB_WR_RDMA_READ:
	case IB_WR_RDMA_READ_WITH_INV:
		if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
			struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
			BUG_ON(!read_hdr);
			if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
				svc_rdma_put_frmr(xprt, ctxt->frmr);
			spin_lock_bh(&xprt->sc_rq_dto_lock);
			set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
			list_add_tail(&read_hdr->dto_q,
				      &xprt->sc_read_complete_q);
			spin_unlock_bh(&xprt->sc_rq_dto_lock);
			svc_xprt_enqueue(&xprt->sc_xprt);
		}
		svc_rdma_put_context(ctxt, 0);
		break;

	default:
		printk(KERN_ERR "svcrdma: unexpected completion type, "
		       "opcode=%d\n",
		       ctxt->wr_op);
		break;
	}
}

/*
 * Send Queue Completion Handler - potentially called on interrupt context.
 *
 * Note that caller must hold a transport reference.
 */
static void sq_cq_reap(struct svcxprt_rdma *xprt)
{
	struct svc_rdma_op_ctxt *ctxt = NULL;
	struct ib_wc wc;
	struct ib_cq *cq = xprt->sc_sq_cq;
	int ret;

	if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
		return;

	ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
	atomic_inc(&rdma_stat_sq_poll);
	while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
		if (wc.status != IB_WC_SUCCESS)
			/* Close the transport */
			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);

		/* Decrement used SQ WR count */
		atomic_dec(&xprt->sc_sq_count);
		wake_up(&xprt->sc_send_wait);

		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
		if (ctxt)
			process_context(xprt, ctxt);

		svc_xprt_put(&xprt->sc_xprt);
	}

	if (ctxt)
		atomic_inc(&rdma_stat_sq_prod);
}

static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
{
	struct svcxprt_rdma *xprt = cq_context;
	unsigned long flags;

	/* Guard against unconditional flush call for destroyed QP */
	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
		return;

	/*
	 * Set the bit regardless of whether or not it's on the list
	 * because it may be on the list already due to an RQ
	 * completion.
	 */
	set_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags);

	/*
	 * If this transport is not already on the DTO transport queue,
	 * add it
	 */
	spin_lock_irqsave(&dto_lock, flags);
	if (list_empty(&xprt->sc_dto_q)) {
		svc_xprt_get(&xprt->sc_xprt);
		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
	}
	spin_unlock_irqrestore(&dto_lock, flags);

	/* Tasklet does all the work to avoid irqsave locks. */
	tasklet_schedule(&dto_tasklet);
}

static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
					     int listener)
{
	struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);

	if (!cma_xprt)
		return NULL;
	svc_xprt_init(&svc_rdma_class, &cma_xprt->sc_xprt, serv);
	INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
	INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
	INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
	INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
	INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
	init_waitqueue_head(&cma_xprt->sc_send_wait);

	spin_lock_init(&cma_xprt->sc_lock);
	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
	spin_lock_init(&cma_xprt->sc_frmr_q_lock);

	cma_xprt->sc_ord = svcrdma_ord;

	cma_xprt->sc_max_req_size = svcrdma_max_req_size;
	cma_xprt->sc_max_requests = svcrdma_max_requests;
	cma_xprt->sc_sq_depth = svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT;
	atomic_set(&cma_xprt->sc_sq_count, 0);
	atomic_set(&cma_xprt->sc_ctxt_used, 0);

	if (listener)
		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);

	return cma_xprt;
}

struct page *svc_rdma_get_page(void)
{
	struct page *page;

	while ((page = alloc_page(GFP_KERNEL)) == NULL) {
		/* If we can't get memory, wait a bit and try again */
		printk(KERN_INFO "svcrdma: out of memory...retrying in 1000 "
		       "jiffies.\n");
		schedule_timeout_uninterruptible(msecs_to_jiffies(1000));
	}
	return page;
}

int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
{
	struct ib_recv_wr recv_wr, *bad_recv_wr;
	struct svc_rdma_op_ctxt *ctxt;
	struct page *page;
	dma_addr_t pa;
	int sge_no;
	int buflen;
	int ret;

	ctxt = svc_rdma_get_context(xprt);
	buflen = 0;
	ctxt->direction = DMA_FROM_DEVICE;
	for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
		BUG_ON(sge_no >= xprt->sc_max_sge);
		page = svc_rdma_get_page();
		ctxt->pages[sge_no] = page;
		pa = ib_dma_map_single(xprt->sc_cm_id->device,
				     page_address(page), PAGE_SIZE,
				     DMA_FROM_DEVICE);
		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
			goto err_put_ctxt;
		atomic_inc(&xprt->sc_dma_used);
		ctxt->sge[sge_no].addr = pa;
		ctxt->sge[sge_no].length = PAGE_SIZE;
		ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
		buflen += PAGE_SIZE;
	}
	ctxt->count = sge_no;
	recv_wr.next = NULL;
	recv_wr.sg_list = &ctxt->sge[0];
	recv_wr.num_sge = ctxt->count;
	recv_wr.wr_id = (u64)(unsigned long)ctxt;

	svc_xprt_get(&xprt->sc_xprt);
	ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
	if (ret) {
		svc_rdma_unmap_dma(ctxt);
		svc_rdma_put_context(ctxt, 1);
		svc_xprt_put(&xprt->sc_xprt);
	}
	return ret;

 err_put_ctxt:
	svc_rdma_put_context(ctxt, 1);
	return -ENOMEM;
}

/*
 * This function handles the CONNECT_REQUEST event on a listening
 * endpoint. It is passed the cma_id for the _new_ connection. The context in
 * this cma_id is inherited from the listening cma_id and is the svc_xprt
 * structure for the listening endpoint.
 *
 * This function creates a new xprt for the new connection and enqueues it on
 * the accept queue for the listent xprt. When the listen thread is kicked, it
 * will call the recvfrom method on the listen xprt which will accept the new
 * connection.
 */
static void handle_connect_req(struct rdma_cm_id *new_cma_id, size_t client_ird)
{
	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
	struct svcxprt_rdma *newxprt;
	struct sockaddr *sa;

	/* Create a new transport */
	newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
	if (!newxprt) {
		dprintk("svcrdma: failed to create new transport\n");
		return;
	}
	newxprt->sc_cm_id = new_cma_id;
	new_cma_id->context = newxprt;
	dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
		newxprt, newxprt->sc_cm_id, listen_xprt);

	/* Save client advertised inbound read limit for use later in accept. */
	newxprt->sc_ord = client_ird;

	/* Set the local and remote addresses in the transport */
	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
	svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
	svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));

	/*
	 * Enqueue the new transport on the accept queue of the listening
	 * transport
	 */
	spin_lock_bh(&listen_xprt->sc_lock);
	list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
	spin_unlock_bh(&listen_xprt->sc_lock);

	/*
	 * Can't use svc_xprt_received here because we are not on a
	 * rqstp thread
	*/
	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
	svc_xprt_enqueue(&listen_xprt->sc_xprt);
}

/*
 * Handles events generated on the listening endpoint. These events will be
 * either be incoming connect requests or adapter removal  events.
 */
static int rdma_listen_handler(struct rdma_cm_id *cma_id,
			       struct rdma_cm_event *event)
{
	struct svcxprt_rdma *xprt = cma_id->context;
	int ret = 0;

	switch (event->event) {
	case RDMA_CM_EVENT_CONNECT_REQUEST:
		dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
			"event=%d\n", cma_id, cma_id->context, event->event);
		handle_connect_req(cma_id,
				   event->param.conn.initiator_depth);
		break;

	case RDMA_CM_EVENT_ESTABLISHED:
		/* Accept complete */
		dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
			"cm_id=%p\n", xprt, cma_id);
		break;

	case RDMA_CM_EVENT_DEVICE_REMOVAL:
		dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
			xprt, cma_id);
		if (xprt)
			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
		break;

	default:
		dprintk("svcrdma: Unexpected event on listening endpoint %p, "
			"event=%d\n", cma_id, event->event);
		break;
	}

	return ret;
}

static int rdma_cma_handler(struct rdma_cm_id *cma_id,
			    struct rdma_cm_event *event)
{
	struct svc_xprt *xprt = cma_id->context;
	struct svcxprt_rdma *rdma =
		container_of(xprt, struct svcxprt_rdma, sc_xprt);
	switch (event->event) {
	case RDMA_CM_EVENT_ESTABLISHED:
		/* Accept complete */
		svc_xprt_get(xprt);
		dprintk("svcrdma: Connection completed on DTO xprt=%p, "
			"cm_id=%p\n", xprt, cma_id);
		clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
		svc_xprt_enqueue(xprt);
		break;
	case RDMA_CM_EVENT_DISCONNECTED:
		dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
			xprt, cma_id);
		if (xprt) {
			set_bit(XPT_CLOSE, &xprt->xpt_flags);
			svc_xprt_enqueue(xprt);
			svc_xprt_put(xprt);
		}
		break;
	case RDMA_CM_EVENT_DEVICE_REMOVAL:
		dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
			"event=%d\n", cma_id, xprt, event->event);
		if (xprt) {
			set_bit(XPT_CLOSE, &xprt->xpt_flags);
			svc_xprt_enqueue(xprt);
		}
		break;
	default:
		dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
			"event=%d\n", cma_id, event->event);
		break;
	}
	return 0;
}

/*
 * Create a listening RDMA service endpoint.
 */
static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
					struct sockaddr *sa, int salen,
					int flags)
{
	struct rdma_cm_id *listen_id;
	struct svcxprt_rdma *cma_xprt;
	struct svc_xprt *xprt;
	int ret;

	dprintk("svcrdma: Creating RDMA socket\n");
	if (sa->sa_family != AF_INET) {
		dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
		return ERR_PTR(-EAFNOSUPPORT);
	}
	cma_xprt = rdma_create_xprt(serv, 1);
	if (!cma_xprt)
		return ERR_PTR(-ENOMEM);
	xprt = &cma_xprt->sc_xprt;

	listen_id = rdma_create_id(rdma_listen_handler, cma_xprt, RDMA_PS_TCP);
	if (IS_ERR(listen_id)) {
		ret = PTR_ERR(listen_id);
		dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
		goto err0;
	}

	ret = rdma_bind_addr(listen_id, sa);
	if (ret) {
		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
		goto err1;
	}
	cma_xprt->sc_cm_id = listen_id;

	ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
	if (ret) {
		dprintk("svcrdma: rdma_listen failed = %d\n", ret);
		goto err1;
	}

	/*
	 * We need to use the address from the cm_id in case the
	 * caller specified 0 for the port number.
	 */
	sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
	svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);

	return &cma_xprt->sc_xprt;

 err1:
	rdma_destroy_id(listen_id);
 err0:
	kfree(cma_xprt);
	return ERR_PTR(ret);
}

static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
{
	struct ib_mr *mr;
	struct ib_fast_reg_page_list *pl;
	struct svc_rdma_fastreg_mr *frmr;

	frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
	if (!frmr)
		goto err;

	mr = ib_alloc_fast_reg_mr(xprt->sc_pd, RPCSVC_MAXPAGES);
	if (IS_ERR(mr))
		goto err_free_frmr;

	pl = ib_alloc_fast_reg_page_list(xprt->sc_cm_id->device,
					 RPCSVC_MAXPAGES);
	if (IS_ERR(pl))
		goto err_free_mr;

	frmr->mr = mr;
	frmr->page_list = pl;
	INIT_LIST_HEAD(&frmr->frmr_list);
	return frmr;

 err_free_mr:
	ib_dereg_mr(mr);
 err_free_frmr:
	kfree(frmr);
 err:
	return ERR_PTR(-ENOMEM);
}

static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
{
	struct svc_rdma_fastreg_mr *frmr;

	while (!list_empty(&xprt->sc_frmr_q)) {
		frmr = list_entry(xprt->sc_frmr_q.next,
				  struct svc_rdma_fastreg_mr, frmr_list);
		list_del_init(&frmr->frmr_list);
		ib_dereg_mr(frmr->mr);
		ib_free_fast_reg_page_list(frmr->page_list);
		kfree(frmr);
	}
}

struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
{
	struct svc_rdma_fastreg_mr *frmr = NULL;

	spin_lock_bh(&rdma->sc_frmr_q_lock);
	if (!list_empty(&rdma->sc_frmr_q)) {
		frmr = list_entry(rdma->sc_frmr_q.next,
				  struct svc_rdma_fastreg_mr, frmr_list);
		list_del_init(&frmr->frmr_list);
		frmr->map_len = 0;
		frmr->page_list_len = 0;
	}
	spin_unlock_bh(&rdma->sc_frmr_q_lock);
	if (frmr)
		return frmr;

	return rdma_alloc_frmr(rdma);
}

static void frmr_unmap_dma(struct svcxprt_rdma *xprt,
			   struct svc_rdma_fastreg_mr *frmr)
{
	int page_no;
	for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
		dma_addr_t addr = frmr->page_list->page_list[page_no];
		if (ib_dma_mapping_error(frmr->mr->device, addr))
			continue;
		atomic_dec(&xprt->sc_dma_used);
		ib_dma_unmap_single(frmr->mr->device, addr, PAGE_SIZE,
				    frmr->direction);
	}
}

void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
		       struct svc_rdma_fastreg_mr *frmr)
{
	if (frmr) {
		frmr_unmap_dma(rdma, frmr);
		spin_lock_bh(&rdma->sc_frmr_q_lock);
		BUG_ON(!list_empty(&frmr->frmr_list));
		list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
		spin_unlock_bh(&rdma->sc_frmr_q_lock);
	}
}

/*
 * This is the xpo_recvfrom function for listening endpoints. Its
 * purpose is to accept incoming connections. The CMA callback handler
 * has already created a new transport and attached it to the new CMA
 * ID.
 *
 * There is a queue of pending connections hung on the listening
 * transport. This queue contains the new svc_xprt structure. This
 * function takes svc_xprt structures off the accept_q and completes
 * the connection.
 */
static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
{
	struct svcxprt_rdma *listen_rdma;
	struct svcxprt_rdma *newxprt = NULL;
	struct rdma_conn_param conn_param;
	struct ib_qp_init_attr qp_attr;
	struct ib_device_attr devattr;
	int uninitialized_var(dma_mr_acc);
	int need_dma_mr;
	int ret;
	int i;

	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
	clear_bit(XPT_CONN, &xprt->xpt_flags);
	/* Get the next entry off the accept list */
	spin_lock_bh(&listen_rdma->sc_lock);
	if (!list_empty(&listen_rdma->sc_accept_q)) {
		newxprt = list_entry(listen_rdma->sc_accept_q.next,
				     struct svcxprt_rdma, sc_accept_q);
		list_del_init(&newxprt->sc_accept_q);
	}
	if (!list_empty(&listen_rdma->sc_accept_q))
		set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
	spin_unlock_bh(&listen_rdma->sc_lock);
	if (!newxprt)
		return NULL;

	dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
		newxprt, newxprt->sc_cm_id);

	ret = ib_query_device(newxprt->sc_cm_id->device, &devattr);
	if (ret) {
		dprintk("svcrdma: could not query device attributes on "
			"device %p, rc=%d\n", newxprt->sc_cm_id->device, ret);
		goto errout;
	}

	/* Qualify the transport resource defaults with the
	 * capabilities of this particular device */
	newxprt->sc_max_sge = min((size_t)devattr.max_sge,
				  (size_t)RPCSVC_MAXPAGES);
	newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
				   (size_t)svcrdma_max_requests);
	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;

	/*
	 * Limit ORD based on client limit, local device limit, and
	 * configured svcrdma limit.
	 */
	newxprt->sc_ord = min_t(size_t, devattr.max_qp_rd_atom, newxprt->sc_ord);
	newxprt->sc_ord = min_t(size_t,	svcrdma_ord, newxprt->sc_ord);

	newxprt->sc_pd = ib_alloc_pd(newxprt->sc_cm_id->device);
	if (IS_ERR(newxprt->sc_pd)) {
		dprintk("svcrdma: error creating PD for connect request\n");
		goto errout;
	}
	newxprt->sc_sq_cq = ib_create_cq(newxprt->sc_cm_id->device,
					 sq_comp_handler,
					 cq_event_handler,
					 newxprt,
					 newxprt->sc_sq_depth,
					 0);
	if (IS_ERR(newxprt->sc_sq_cq)) {
		dprintk("svcrdma: error creating SQ CQ for connect request\n");
		goto errout;
	}
	newxprt->sc_rq_cq = ib_create_cq(newxprt->sc_cm_id->device,
					 rq_comp_handler,
					 cq_event_handler,
					 newxprt,
					 newxprt->sc_max_requests,
					 0);
	if (IS_ERR(newxprt->sc_rq_cq)) {
		dprintk("svcrdma: error creating RQ CQ for connect request\n");
		goto errout;
	}

	memset(&qp_attr, 0, sizeof qp_attr);
	qp_attr.event_handler = qp_event_handler;
	qp_attr.qp_context = &newxprt->sc_xprt;
	qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
	qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
	qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
	qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
	qp_attr.qp_type = IB_QPT_RC;
	qp_attr.send_cq = newxprt->sc_sq_cq;
	qp_attr.recv_cq = newxprt->sc_rq_cq;
	dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n"
		"    cm_id->device=%p, sc_pd->device=%p\n"
		"    cap.max_send_wr = %d\n"
		"    cap.max_recv_wr = %d\n"
		"    cap.max_send_sge = %d\n"
		"    cap.max_recv_sge = %d\n",
		newxprt->sc_cm_id, newxprt->sc_pd,
		newxprt->sc_cm_id->device, newxprt->sc_pd->device,
		qp_attr.cap.max_send_wr,
		qp_attr.cap.max_recv_wr,
		qp_attr.cap.max_send_sge,
		qp_attr.cap.max_recv_sge);

	ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
	if (ret) {
		/*
		 * XXX: This is a hack. We need a xx_request_qp interface
		 * that will adjust the qp_attr's with a best-effort
		 * number
		 */
		qp_attr.cap.max_send_sge -= 2;
		qp_attr.cap.max_recv_sge -= 2;
		ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd,
				     &qp_attr);
		if (ret) {
			dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
			goto errout;
		}
		newxprt->sc_max_sge = qp_attr.cap.max_send_sge;
		newxprt->sc_max_sge = qp_attr.cap.max_recv_sge;
		newxprt->sc_sq_depth = qp_attr.cap.max_send_wr;
		newxprt->sc_max_requests = qp_attr.cap.max_recv_wr;
	}
	newxprt->sc_qp = newxprt->sc_cm_id->qp;

	/*
	 * Use the most secure set of MR resources based on the
	 * transport type and available memory management features in
	 * the device. Here's the table implemented below:
	 *
	 *		Fast	Global	DMA	Remote WR
	 *		Reg	LKEY	MR	Access
	 *		Sup'd	Sup'd	Needed	Needed
	 *
	 * IWARP	N	N	Y	Y
	 *		N	Y	Y	Y
	 *		Y	N	Y	N
	 *		Y	Y	N	-
	 *
	 * IB		N	N	Y	N
	 *		N	Y	N	-
	 *		Y	N	Y	N
	 *		Y	Y	N	-
	 *
	 * NB:	iWARP requires remote write access for the data sink
	 *	of an RDMA_READ. IB does not.
	 */
	if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
		newxprt->sc_frmr_pg_list_len =
			devattr.max_fast_reg_page_list_len;
		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
	}

	/*
	 * Determine if a DMA MR is required and if so, what privs are required
	 */
	switch (rdma_node_get_transport(newxprt->sc_cm_id->device->node_type)) {
	case RDMA_TRANSPORT_IWARP:
		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
		if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
			need_dma_mr = 1;
			dma_mr_acc =
				(IB_ACCESS_LOCAL_WRITE |
				 IB_ACCESS_REMOTE_WRITE);
		} else if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
			need_dma_mr = 1;
			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
		} else
			need_dma_mr = 0;
		break;
	case RDMA_TRANSPORT_IB:
		if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
			need_dma_mr = 1;
			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
		} else
			need_dma_mr = 0;
		break;
	default:
		goto errout;
	}

	/* Create the DMA MR if needed, otherwise, use the DMA LKEY */
	if (need_dma_mr) {
		/* Register all of physical memory */
		newxprt->sc_phys_mr =
			ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
		if (IS_ERR(newxprt->sc_phys_mr)) {
			dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
				ret);
			goto errout;
		}
		newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
	} else
		newxprt->sc_dma_lkey =
			newxprt->sc_cm_id->device->local_dma_lkey;

	/* Post receive buffers */
	for (i = 0; i < newxprt->sc_max_requests; i++) {
		ret = svc_rdma_post_recv(newxprt);
		if (ret) {
			dprintk("svcrdma: failure posting receive buffers\n");
			goto errout;
		}
	}

	/* Swap out the handler */
	newxprt->sc_cm_id->event_handler = rdma_cma_handler;

	/*
	 * Arm the CQs for the SQ and RQ before accepting so we can't
	 * miss the first message
	 */
	ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
	ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);

	/* Accept Connection */
	set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
	memset(&conn_param, 0, sizeof conn_param);
	conn_param.responder_resources = 0;
	conn_param.initiator_depth = newxprt->sc_ord;
	ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
	if (ret) {
		dprintk("svcrdma: failed to accept new connection, ret=%d\n",
		       ret);
		goto errout;
	}

	dprintk("svcrdma: new connection %p accepted with the following "
		"attributes:\n"
		"    local_ip        : %pI4\n"
		"    local_port	     : %d\n"
		"    remote_ip       : %pI4\n"
		"    remote_port     : %d\n"
		"    max_sge         : %d\n"
		"    sq_depth        : %d\n"
		"    max_requests    : %d\n"
		"    ord             : %d\n",
		newxprt,
		&((struct sockaddr_in *)&newxprt->sc_cm_id->
			 route.addr.src_addr)->sin_addr.s_addr,
		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
		       route.addr.src_addr)->sin_port),
		&((struct sockaddr_in *)&newxprt->sc_cm_id->
			 route.addr.dst_addr)->sin_addr.s_addr,
		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
		       route.addr.dst_addr)->sin_port),
		newxprt->sc_max_sge,
		newxprt->sc_sq_depth,
		newxprt->sc_max_requests,
		newxprt->sc_ord);

	return &newxprt->sc_xprt;

 errout:
	dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
	/* Take a reference in case the DTO handler runs */
	svc_xprt_get(&newxprt->sc_xprt);
	if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
		ib_destroy_qp(newxprt->sc_qp);
	rdma_destroy_id(newxprt->sc_cm_id);
	/* This call to put will destroy the transport */
	svc_xprt_put(&newxprt->sc_xprt);
	return NULL;
}

static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
{
}

/*
 * When connected, an svc_xprt has at least two references:
 *
 * - A reference held by the cm_id between the ESTABLISHED and
 *   DISCONNECTED events. If the remote peer disconnected first, this
 *   reference could be gone.
 *
 * - A reference held by the svc_recv code that called this function
 *   as part of close processing.
 *
 * At a minimum one references should still be held.
 */
static void svc_rdma_detach(struct svc_xprt *xprt)
{
	struct svcxprt_rdma *rdma =
		container_of(xprt, struct svcxprt_rdma, sc_xprt);
	dprintk("svc: svc_rdma_detach(%p)\n", xprt);

	/* Disconnect and flush posted WQE */
	rdma_disconnect(rdma->sc_cm_id);
}

static void __svc_rdma_free(struct work_struct *work)
{
	struct svcxprt_rdma *rdma =
		container_of(work, struct svcxprt_rdma, sc_work);
	dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);

	/* We should only be called from kref_put */
	BUG_ON(atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0);

	/*
	 * Destroy queued, but not processed read completions. Note
	 * that this cleanup has to be done before destroying the
	 * cm_id because the device ptr is needed to unmap the dma in
	 * svc_rdma_put_context.
	 */
	while (!list_empty(&rdma->sc_read_complete_q)) {
		struct svc_rdma_op_ctxt *ctxt;
		ctxt = list_entry(rdma->sc_read_complete_q.next,
				  struct svc_rdma_op_ctxt,
				  dto_q);
		list_del_init(&ctxt->dto_q);
		svc_rdma_put_context(ctxt, 1);
	}

	/* Destroy queued, but not processed recv completions */
	while (!list_empty(&rdma->sc_rq_dto_q)) {
		struct svc_rdma_op_ctxt *ctxt;
		ctxt = list_entry(rdma->sc_rq_dto_q.next,
				  struct svc_rdma_op_ctxt,
				  dto_q);
		list_del_init(&ctxt->dto_q);
		svc_rdma_put_context(ctxt, 1);
	}

	/* Warn if we leaked a resource or under-referenced */
	WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
	WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);

	/* De-allocate fastreg mr */
	rdma_dealloc_frmr_q(rdma);

	/* Destroy the QP if present (not a listener) */
	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
		ib_destroy_qp(rdma->sc_qp);

	if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
		ib_destroy_cq(rdma->sc_sq_cq);

	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
		ib_destroy_cq(rdma->sc_rq_cq);

	if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
		ib_dereg_mr(rdma->sc_phys_mr);

	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
		ib_dealloc_pd(rdma->sc_pd);

	/* Destroy the CM ID */
	rdma_destroy_id(rdma->sc_cm_id);

	kfree(rdma);
}

static void svc_rdma_free(struct svc_xprt *xprt)
{
	struct svcxprt_rdma *rdma =
		container_of(xprt, struct svcxprt_rdma, sc_xprt);
	INIT_WORK(&rdma->sc_work, __svc_rdma_free);
	schedule_work(&rdma->sc_work);
}

static int svc_rdma_has_wspace(struct svc_xprt *xprt)
{
	struct svcxprt_rdma *rdma =
		container_of(xprt, struct svcxprt_rdma, sc_xprt);

	/*
	 * If there are fewer SQ WR available than required to send a
	 * simple response, return false.
	 */
	if ((rdma->sc_sq_depth - atomic_read(&rdma->sc_sq_count) < 3))
		return 0;

	/*
	 * ...or there are already waiters on the SQ,
	 * return false.
	 */
	if (waitqueue_active(&rdma->sc_send_wait))
		return 0;

	/* Otherwise return true. */
	return 1;
}

/*
 * Attempt to register the kvec representing the RPC memory with the
 * device.
 *
 * Returns:
 *  NULL : The device does not support fastreg or there were no more
 *         fastreg mr.
 *  frmr : The kvec register request was successfully posted.
 *    <0 : An error was encountered attempting to register the kvec.
 */
int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
		     struct svc_rdma_fastreg_mr *frmr)
{
	struct ib_send_wr fastreg_wr;
	u8 key;

	/* Bump the key */
	key = (u8)(frmr->mr->lkey & 0x000000FF);
	ib_update_fast_reg_key(frmr->mr, ++key);

	/* Prepare FASTREG WR */
	memset(&fastreg_wr, 0, sizeof fastreg_wr);
	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
	fastreg_wr.send_flags = IB_SEND_SIGNALED;
	fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
	fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
	fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
	fastreg_wr.wr.fast_reg.length = frmr->map_len;
	fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
	fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
	return svc_rdma_send(xprt, &fastreg_wr);
}

int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
{
	struct ib_send_wr *bad_wr, *n_wr;
	int wr_count;
	int i;
	int ret;

	if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
		return -ENOTCONN;

	BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
	wr_count = 1;
	for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
		wr_count++;

	/* If the SQ is full, wait until an SQ entry is available */
	while (1) {
		spin_lock_bh(&xprt->sc_lock);
		if (xprt->sc_sq_depth < atomic_read(&xprt->sc_sq_count) + wr_count) {
			spin_unlock_bh(&xprt->sc_lock);
			atomic_inc(&rdma_stat_sq_starve);

			/* See if we can opportunistically reap SQ WR to make room */
			sq_cq_reap(xprt);

			/* Wait until SQ WR available if SQ still full */
			wait_event(xprt->sc_send_wait,
				   atomic_read(&xprt->sc_sq_count) <
				   xprt->sc_sq_depth);
			if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
				return 0;
			continue;
		}
		/* Take a transport ref for each WR posted */
		for (i = 0; i < wr_count; i++)
			svc_xprt_get(&xprt->sc_xprt);

		/* Bump used SQ WR count and post */
		atomic_add(wr_count, &xprt->sc_sq_count);
		ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
		if (ret) {
			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
			atomic_sub(wr_count, &xprt->sc_sq_count);
			for (i = 0; i < wr_count; i ++)
				svc_xprt_put(&xprt->sc_xprt);
			dprintk("svcrdma: failed to post SQ WR rc=%d, "
			       "sc_sq_count=%d, sc_sq_depth=%d\n",
			       ret, atomic_read(&xprt->sc_sq_count),
			       xprt->sc_sq_depth);
		}
		spin_unlock_bh(&xprt->sc_lock);
		if (ret)
			wake_up(&xprt->sc_send_wait);
		break;
	}
	return ret;
}

void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
			 enum rpcrdma_errcode err)
{
	struct ib_send_wr err_wr;
	struct ib_sge sge;
	struct page *p;
	struct svc_rdma_op_ctxt *ctxt;
	u32 *va;
	int length;
	int ret;

	p = svc_rdma_get_page();
	va = page_address(p);

	/* XDR encode error */
	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);

	/* Prepare SGE for local address */
	sge.addr = ib_dma_map_single(xprt->sc_cm_id->device,
				   page_address(p), PAGE_SIZE, DMA_FROM_DEVICE);
	if (ib_dma_mapping_error(xprt->sc_cm_id->device, sge.addr)) {
		put_page(p);
		return;
	}
	atomic_inc(&xprt->sc_dma_used);
	sge.lkey = xprt->sc_dma_lkey;
	sge.length = length;

	ctxt = svc_rdma_get_context(xprt);
	ctxt->count = 1;
	ctxt->pages[0] = p;

	/* Prepare SEND WR */
	memset(&err_wr, 0, sizeof err_wr);
	ctxt->wr_op = IB_WR_SEND;
	err_wr.wr_id = (unsigned long)ctxt;
	err_wr.sg_list = &sge;
	err_wr.num_sge = 1;
	err_wr.opcode = IB_WR_SEND;
	err_wr.send_flags = IB_SEND_SIGNALED;

	/* Post It */
	ret = svc_rdma_send(xprt, &err_wr);
	if (ret) {
		dprintk("svcrdma: Error %d posting send for protocol error\n",
			ret);
		ib_dma_unmap_single(xprt->sc_cm_id->device,
				  sge.addr, PAGE_SIZE,
				  DMA_FROM_DEVICE);
		svc_rdma_put_context(ctxt, 1);
	}
}