summaryrefslogtreecommitdiff
path: root/fs/cifs/transport.c
blob: c1725b55f36488fd2532bef47176342aacad66b4 (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
/*
 *   fs/cifs/transport.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *   Jeremy Allison (jra@samba.org) 2006.
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/fs.h>
#include <linux/list.h>
#include <linux/gfp.h>
#include <linux/wait.h>
#include <linux/net.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/tcp.h>
#include <linux/bvec.h>
#include <linux/highmem.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <linux/mempool.h>
#include <linux/sched/signal.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "smbdirect.h"

/* Max number of iovectors we can use off the stack when sending requests. */
#define CIFS_MAX_IOV_SIZE 8

void
cifs_wake_up_task(struct mid_q_entry *mid)
{
	wake_up_process(mid->callback_data);
}

struct mid_q_entry *
AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
{
	struct mid_q_entry *temp;

	if (server == NULL) {
		cifs_dbg(VFS, "Null TCP session in AllocMidQEntry\n");
		return NULL;
	}

	temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
	memset(temp, 0, sizeof(struct mid_q_entry));
	kref_init(&temp->refcount);
	temp->mid = get_mid(smb_buffer);
	temp->pid = current->pid;
	temp->command = cpu_to_le16(smb_buffer->Command);
	cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
	/*	do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
	/* when mid allocated can be before when sent */
	temp->when_alloc = jiffies;
	temp->server = server;

	/*
	 * The default is for the mid to be synchronous, so the
	 * default callback just wakes up the current task.
	 */
	get_task_struct(current);
	temp->creator = current;
	temp->callback = cifs_wake_up_task;
	temp->callback_data = current;

	atomic_inc(&midCount);
	temp->mid_state = MID_REQUEST_ALLOCATED;
	return temp;
}

static void _cifs_mid_q_entry_release(struct kref *refcount)
{
	struct mid_q_entry *midEntry =
			container_of(refcount, struct mid_q_entry, refcount);
#ifdef CONFIG_CIFS_STATS2
	__le16 command = midEntry->server->vals->lock_cmd;
	__u16 smb_cmd = le16_to_cpu(midEntry->command);
	unsigned long now;
	unsigned long roundtrip_time;
#endif
	struct TCP_Server_Info *server = midEntry->server;

	if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) &&
	    midEntry->mid_state == MID_RESPONSE_RECEIVED &&
	    server->ops->handle_cancelled_mid)
		server->ops->handle_cancelled_mid(midEntry, server);

	midEntry->mid_state = MID_FREE;
	atomic_dec(&midCount);
	if (midEntry->large_buf)
		cifs_buf_release(midEntry->resp_buf);
	else
		cifs_small_buf_release(midEntry->resp_buf);
#ifdef CONFIG_CIFS_STATS2
	now = jiffies;
	if (now < midEntry->when_alloc)
		cifs_server_dbg(VFS, "Invalid mid allocation time\n");
	roundtrip_time = now - midEntry->when_alloc;

	if (smb_cmd < NUMBER_OF_SMB2_COMMANDS) {
		if (atomic_read(&server->num_cmds[smb_cmd]) == 0) {
			server->slowest_cmd[smb_cmd] = roundtrip_time;
			server->fastest_cmd[smb_cmd] = roundtrip_time;
		} else {
			if (server->slowest_cmd[smb_cmd] < roundtrip_time)
				server->slowest_cmd[smb_cmd] = roundtrip_time;
			else if (server->fastest_cmd[smb_cmd] > roundtrip_time)
				server->fastest_cmd[smb_cmd] = roundtrip_time;
		}
		cifs_stats_inc(&server->num_cmds[smb_cmd]);
		server->time_per_cmd[smb_cmd] += roundtrip_time;
	}
	/*
	 * commands taking longer than one second (default) can be indications
	 * that something is wrong, unless it is quite a slow link or a very
	 * busy server. Note that this calc is unlikely or impossible to wrap
	 * as long as slow_rsp_threshold is not set way above recommended max
	 * value (32767 ie 9 hours) and is generally harmless even if wrong
	 * since only affects debug counters - so leaving the calc as simple
	 * comparison rather than doing multiple conversions and overflow
	 * checks
	 */
	if ((slow_rsp_threshold != 0) &&
	    time_after(now, midEntry->when_alloc + (slow_rsp_threshold * HZ)) &&
	    (midEntry->command != command)) {
		/*
		 * smb2slowcmd[NUMBER_OF_SMB2_COMMANDS] counts by command
		 * NB: le16_to_cpu returns unsigned so can not be negative below
		 */
		if (smb_cmd < NUMBER_OF_SMB2_COMMANDS)
			cifs_stats_inc(&server->smb2slowcmd[smb_cmd]);

		trace_smb3_slow_rsp(smb_cmd, midEntry->mid, midEntry->pid,
			       midEntry->when_sent, midEntry->when_received);
		if (cifsFYI & CIFS_TIMER) {
			pr_debug("slow rsp: cmd %d mid %llu",
				 midEntry->command, midEntry->mid);
			cifs_info("A: 0x%lx S: 0x%lx R: 0x%lx\n",
				  now - midEntry->when_alloc,
				  now - midEntry->when_sent,
				  now - midEntry->when_received);
		}
	}
#endif
	put_task_struct(midEntry->creator);

	mempool_free(midEntry, cifs_mid_poolp);
}

void cifs_mid_q_entry_release(struct mid_q_entry *midEntry)
{
	spin_lock(&GlobalMid_Lock);
	kref_put(&midEntry->refcount, _cifs_mid_q_entry_release);
	spin_unlock(&GlobalMid_Lock);
}

void DeleteMidQEntry(struct mid_q_entry *midEntry)
{
	cifs_mid_q_entry_release(midEntry);
}

void
cifs_delete_mid(struct mid_q_entry *mid)
{
	spin_lock(&GlobalMid_Lock);
	if (!(mid->mid_flags & MID_DELETED)) {
		list_del_init(&mid->qhead);
		mid->mid_flags |= MID_DELETED;
	}
	spin_unlock(&GlobalMid_Lock);

	DeleteMidQEntry(mid);
}

/*
 * smb_send_kvec - send an array of kvecs to the server
 * @server:	Server to send the data to
 * @smb_msg:	Message to send
 * @sent:	amount of data sent on socket is stored here
 *
 * Our basic "send data to server" function. Should be called with srv_mutex
 * held. The caller is responsible for handling the results.
 */
static int
smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
	      size_t *sent)
{
	int rc = 0;
	int retries = 0;
	struct socket *ssocket = server->ssocket;

	*sent = 0;

	smb_msg->msg_name = (struct sockaddr *) &server->dstaddr;
	smb_msg->msg_namelen = sizeof(struct sockaddr);
	smb_msg->msg_control = NULL;
	smb_msg->msg_controllen = 0;
	if (server->noblocksnd)
		smb_msg->msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
	else
		smb_msg->msg_flags = MSG_NOSIGNAL;

	while (msg_data_left(smb_msg)) {
		/*
		 * If blocking send, we try 3 times, since each can block
		 * for 5 seconds. For nonblocking  we have to try more
		 * but wait increasing amounts of time allowing time for
		 * socket to clear.  The overall time we wait in either
		 * case to send on the socket is about 15 seconds.
		 * Similarly we wait for 15 seconds for a response from
		 * the server in SendReceive[2] for the server to send
		 * a response back for most types of requests (except
		 * SMB Write past end of file which can be slow, and
		 * blocking lock operations). NFS waits slightly longer
		 * than CIFS, but this can make it take longer for
		 * nonresponsive servers to be detected and 15 seconds
		 * is more than enough time for modern networks to
		 * send a packet.  In most cases if we fail to send
		 * after the retries we will kill the socket and
		 * reconnect which may clear the network problem.
		 */
		rc = sock_sendmsg(ssocket, smb_msg);
		if (rc == -EAGAIN) {
			retries++;
			if (retries >= 14 ||
			    (!server->noblocksnd && (retries > 2))) {
				cifs_server_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
					 ssocket);
				return -EAGAIN;
			}
			msleep(1 << retries);
			continue;
		}

		if (rc < 0)
			return rc;

		if (rc == 0) {
			/* should never happen, letting socket clear before
			   retrying is our only obvious option here */
			cifs_server_dbg(VFS, "tcp sent no data\n");
			msleep(500);
			continue;
		}

		/* send was at least partially successful */
		*sent += rc;
		retries = 0; /* in case we get ENOSPC on the next send */
	}
	return 0;
}

unsigned long
smb_rqst_len(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
	unsigned int i;
	struct kvec *iov;
	int nvec;
	unsigned long buflen = 0;

	if (server->vals->header_preamble_size == 0 &&
	    rqst->rq_nvec >= 2 && rqst->rq_iov[0].iov_len == 4) {
		iov = &rqst->rq_iov[1];
		nvec = rqst->rq_nvec - 1;
	} else {
		iov = rqst->rq_iov;
		nvec = rqst->rq_nvec;
	}

	/* total up iov array first */
	for (i = 0; i < nvec; i++)
		buflen += iov[i].iov_len;

	/*
	 * Add in the page array if there is one. The caller needs to make
	 * sure rq_offset and rq_tailsz are set correctly. If a buffer of
	 * multiple pages ends at page boundary, rq_tailsz needs to be set to
	 * PAGE_SIZE.
	 */
	if (rqst->rq_npages) {
		if (rqst->rq_npages == 1)
			buflen += rqst->rq_tailsz;
		else {
			/*
			 * If there is more than one page, calculate the
			 * buffer length based on rq_offset and rq_tailsz
			 */
			buflen += rqst->rq_pagesz * (rqst->rq_npages - 1) -
					rqst->rq_offset;
			buflen += rqst->rq_tailsz;
		}
	}

	return buflen;
}

static int
__smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
		struct smb_rqst *rqst)
{
	int rc = 0;
	struct kvec *iov;
	int n_vec;
	unsigned int send_length = 0;
	unsigned int i, j;
	sigset_t mask, oldmask;
	size_t total_len = 0, sent, size;
	struct socket *ssocket = server->ssocket;
	struct msghdr smb_msg;
	__be32 rfc1002_marker;

	if (cifs_rdma_enabled(server)) {
		/* return -EAGAIN when connecting or reconnecting */
		rc = -EAGAIN;
		if (server->smbd_conn)
			rc = smbd_send(server, num_rqst, rqst);
		goto smbd_done;
	}

	if (ssocket == NULL)
		return -EAGAIN;

	if (fatal_signal_pending(current)) {
		cifs_dbg(FYI, "signal pending before send request\n");
		return -ERESTARTSYS;
	}

	/* cork the socket */
	tcp_sock_set_cork(ssocket->sk, true);

	for (j = 0; j < num_rqst; j++)
		send_length += smb_rqst_len(server, &rqst[j]);
	rfc1002_marker = cpu_to_be32(send_length);

	/*
	 * We should not allow signals to interrupt the network send because
	 * any partial send will cause session reconnects thus increasing
	 * latency of system calls and overload a server with unnecessary
	 * requests.
	 */

	sigfillset(&mask);
	sigprocmask(SIG_BLOCK, &mask, &oldmask);

	/* Generate a rfc1002 marker for SMB2+ */
	if (server->vals->header_preamble_size == 0) {
		struct kvec hiov = {
			.iov_base = &rfc1002_marker,
			.iov_len  = 4
		};
		iov_iter_kvec(&smb_msg.msg_iter, WRITE, &hiov, 1, 4);
		rc = smb_send_kvec(server, &smb_msg, &sent);
		if (rc < 0)
			goto unmask;

		total_len += sent;
		send_length += 4;
	}

	cifs_dbg(FYI, "Sending smb: smb_len=%u\n", send_length);

	for (j = 0; j < num_rqst; j++) {
		iov = rqst[j].rq_iov;
		n_vec = rqst[j].rq_nvec;

		size = 0;
		for (i = 0; i < n_vec; i++) {
			dump_smb(iov[i].iov_base, iov[i].iov_len);
			size += iov[i].iov_len;
		}

		iov_iter_kvec(&smb_msg.msg_iter, WRITE, iov, n_vec, size);

		rc = smb_send_kvec(server, &smb_msg, &sent);
		if (rc < 0)
			goto unmask;

		total_len += sent;

		/* now walk the page array and send each page in it */
		for (i = 0; i < rqst[j].rq_npages; i++) {
			struct bio_vec bvec;

			bvec.bv_page = rqst[j].rq_pages[i];
			rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
					     &bvec.bv_offset);

			iov_iter_bvec(&smb_msg.msg_iter, WRITE,
				      &bvec, 1, bvec.bv_len);
			rc = smb_send_kvec(server, &smb_msg, &sent);
			if (rc < 0)
				break;

			total_len += sent;
		}
	}

unmask:
	sigprocmask(SIG_SETMASK, &oldmask, NULL);

	/*
	 * If signal is pending but we have already sent the whole packet to
	 * the server we need to return success status to allow a corresponding
	 * mid entry to be kept in the pending requests queue thus allowing
	 * to handle responses from the server by the client.
	 *
	 * If only part of the packet has been sent there is no need to hide
	 * interrupt because the session will be reconnected anyway, so there
	 * won't be any response from the server to handle.
	 */

	if (signal_pending(current) && (total_len != send_length)) {
		cifs_dbg(FYI, "signal is pending after attempt to send\n");
		rc = -ERESTARTSYS;
	}

	/* uncork it */
	tcp_sock_set_cork(ssocket->sk, false);

	if ((total_len > 0) && (total_len != send_length)) {
		cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
			 send_length, total_len);
		/*
		 * If we have only sent part of an SMB then the next SMB could
		 * be taken as the remainder of this one. We need to kill the
		 * socket so the server throws away the partial SMB
		 */
		server->tcpStatus = CifsNeedReconnect;
		trace_smb3_partial_send_reconnect(server->CurrentMid,
						  server->conn_id, server->hostname);
	}
smbd_done:
	if (rc < 0 && rc != -EINTR)
		cifs_server_dbg(VFS, "Error %d sending data on socket to server\n",
			 rc);
	else if (rc > 0)
		rc = 0;

	return rc;
}

static int
smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
	      struct smb_rqst *rqst, int flags)
{
	struct kvec iov;
	struct smb2_transform_hdr *tr_hdr;
	struct smb_rqst cur_rqst[MAX_COMPOUND];
	int rc;

	if (!(flags & CIFS_TRANSFORM_REQ))
		return __smb_send_rqst(server, num_rqst, rqst);

	if (num_rqst > MAX_COMPOUND - 1)
		return -ENOMEM;

	if (!server->ops->init_transform_rq) {
		cifs_server_dbg(VFS, "Encryption requested but transform callback is missing\n");
		return -EIO;
	}

	tr_hdr = kmalloc(sizeof(*tr_hdr), GFP_NOFS);
	if (!tr_hdr)
		return -ENOMEM;

	memset(&cur_rqst[0], 0, sizeof(cur_rqst));
	memset(&iov, 0, sizeof(iov));
	memset(tr_hdr, 0, sizeof(*tr_hdr));

	iov.iov_base = tr_hdr;
	iov.iov_len = sizeof(*tr_hdr);
	cur_rqst[0].rq_iov = &iov;
	cur_rqst[0].rq_nvec = 1;

	rc = server->ops->init_transform_rq(server, num_rqst + 1,
					    &cur_rqst[0], rqst);
	if (rc)
		goto out;

	rc = __smb_send_rqst(server, num_rqst + 1, &cur_rqst[0]);
	smb3_free_compound_rqst(num_rqst, &cur_rqst[1]);
out:
	kfree(tr_hdr);
	return rc;
}

int
smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
	 unsigned int smb_buf_length)
{
	struct kvec iov[2];
	struct smb_rqst rqst = { .rq_iov = iov,
				 .rq_nvec = 2 };

	iov[0].iov_base = smb_buffer;
	iov[0].iov_len = 4;
	iov[1].iov_base = (char *)smb_buffer + 4;
	iov[1].iov_len = smb_buf_length;

	return __smb_send_rqst(server, 1, &rqst);
}

static int
wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
		      const int timeout, const int flags,
		      unsigned int *instance)
{
	long rc;
	int *credits;
	int optype;
	long int t;
	int scredits, in_flight;

	if (timeout < 0)
		t = MAX_JIFFY_OFFSET;
	else
		t = msecs_to_jiffies(timeout);

	optype = flags & CIFS_OP_MASK;

	*instance = 0;

	credits = server->ops->get_credits_field(server, optype);
	/* Since an echo is already inflight, no need to wait to send another */
	if (*credits <= 0 && optype == CIFS_ECHO_OP)
		return -EAGAIN;

	spin_lock(&server->req_lock);
	if ((flags & CIFS_TIMEOUT_MASK) == CIFS_NON_BLOCKING) {
		/* oplock breaks must not be held up */
		server->in_flight++;
		if (server->in_flight > server->max_in_flight)
			server->max_in_flight = server->in_flight;
		*credits -= 1;
		*instance = server->reconnect_instance;
		scredits = *credits;
		in_flight = server->in_flight;
		spin_unlock(&server->req_lock);

		trace_smb3_add_credits(server->CurrentMid,
				server->conn_id, server->hostname, scredits, -1, in_flight);
		cifs_dbg(FYI, "%s: remove %u credits total=%d\n",
				__func__, 1, scredits);

		return 0;
	}

	while (1) {
		if (*credits < num_credits) {
			scredits = *credits;
			spin_unlock(&server->req_lock);

			cifs_num_waiters_inc(server);
			rc = wait_event_killable_timeout(server->request_q,
				has_credits(server, credits, num_credits), t);
			cifs_num_waiters_dec(server);
			if (!rc) {
				spin_lock(&server->req_lock);
				scredits = *credits;
				in_flight = server->in_flight;
				spin_unlock(&server->req_lock);

				trace_smb3_credit_timeout(server->CurrentMid,
						server->conn_id, server->hostname, scredits,
						num_credits, in_flight);
				cifs_server_dbg(VFS, "wait timed out after %d ms\n",
						timeout);
				return -EBUSY;
			}
			if (rc == -ERESTARTSYS)
				return -ERESTARTSYS;
			spin_lock(&server->req_lock);
		} else {
			if (server->tcpStatus == CifsExiting) {
				spin_unlock(&server->req_lock);
				return -ENOENT;
			}

			/*
			 * For normal commands, reserve the last MAX_COMPOUND
			 * credits to compound requests.
			 * Otherwise these compounds could be permanently
			 * starved for credits by single-credit requests.
			 *
			 * To prevent spinning CPU, block this thread until
			 * there are >MAX_COMPOUND credits available.
			 * But only do this is we already have a lot of
			 * credits in flight to avoid triggering this check
			 * for servers that are slow to hand out credits on
			 * new sessions.
			 */
			if (!optype && num_credits == 1 &&
			    server->in_flight > 2 * MAX_COMPOUND &&
			    *credits <= MAX_COMPOUND) {
				spin_unlock(&server->req_lock);

				cifs_num_waiters_inc(server);
				rc = wait_event_killable_timeout(
					server->request_q,
					has_credits(server, credits,
						    MAX_COMPOUND + 1),
					t);
				cifs_num_waiters_dec(server);
				if (!rc) {
					spin_lock(&server->req_lock);
					scredits = *credits;
					in_flight = server->in_flight;
					spin_unlock(&server->req_lock);

					trace_smb3_credit_timeout(
							server->CurrentMid,
							server->conn_id, server->hostname,
							scredits, num_credits, in_flight);
					cifs_server_dbg(VFS, "wait timed out after %d ms\n",
							timeout);
					return -EBUSY;
				}
				if (rc == -ERESTARTSYS)
					return -ERESTARTSYS;
				spin_lock(&server->req_lock);
				continue;
			}

			/*
			 * Can not count locking commands against total
			 * as they are allowed to block on server.
			 */

			/* update # of requests on the wire to server */
			if ((flags & CIFS_TIMEOUT_MASK) != CIFS_BLOCKING_OP) {
				*credits -= num_credits;
				server->in_flight += num_credits;
				if (server->in_flight > server->max_in_flight)
					server->max_in_flight = server->in_flight;
				*instance = server->reconnect_instance;
			}
			scredits = *credits;
			in_flight = server->in_flight;
			spin_unlock(&server->req_lock);

			trace_smb3_add_credits(server->CurrentMid,
					server->conn_id, server->hostname, scredits,
					-(num_credits), in_flight);
			cifs_dbg(FYI, "%s: remove %u credits total=%d\n",
					__func__, num_credits, scredits);
			break;
		}
	}
	return 0;
}

static int
wait_for_free_request(struct TCP_Server_Info *server, const int flags,
		      unsigned int *instance)
{
	return wait_for_free_credits(server, 1, -1, flags,
				     instance);
}

static int
wait_for_compound_request(struct TCP_Server_Info *server, int num,
			  const int flags, unsigned int *instance)
{
	int *credits;
	int scredits, in_flight;

	credits = server->ops->get_credits_field(server, flags & CIFS_OP_MASK);

	spin_lock(&server->req_lock);
	scredits = *credits;
	in_flight = server->in_flight;

	if (*credits < num) {
		/*
		 * If the server is tight on resources or just gives us less
		 * credits for other reasons (e.g. requests are coming out of
		 * order and the server delays granting more credits until it
		 * processes a missing mid) and we exhausted most available
		 * credits there may be situations when we try to send
		 * a compound request but we don't have enough credits. At this
		 * point the client needs to decide if it should wait for
		 * additional credits or fail the request. If at least one
		 * request is in flight there is a high probability that the
		 * server will return enough credits to satisfy this compound
		 * request.
		 *
		 * Return immediately if no requests in flight since we will be
		 * stuck on waiting for credits.
		 */
		if (server->in_flight == 0) {
			spin_unlock(&server->req_lock);
			trace_smb3_insufficient_credits(server->CurrentMid,
					server->conn_id, server->hostname, scredits,
					num, in_flight);
			cifs_dbg(FYI, "%s: %d requests in flight, needed %d total=%d\n",
					__func__, in_flight, num, scredits);
			return -EDEADLK;
		}
	}
	spin_unlock(&server->req_lock);

	return wait_for_free_credits(server, num, 60000, flags,
				     instance);
}

int
cifs_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
		      unsigned int *num, struct cifs_credits *credits)
{
	*num = size;
	credits->value = 0;
	credits->instance = server->reconnect_instance;
	return 0;
}

static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
			struct mid_q_entry **ppmidQ)
{
	if (ses->server->tcpStatus == CifsExiting) {
		return -ENOENT;
	}

	if (ses->server->tcpStatus == CifsNeedReconnect) {
		cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
		return -EAGAIN;
	}

	if (ses->status == CifsNew) {
		if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
			(in_buf->Command != SMB_COM_NEGOTIATE))
			return -EAGAIN;
		/* else ok - we are setting up session */
	}

	if (ses->status == CifsExiting) {
		/* check if SMB session is bad because we are setting it up */
		if (in_buf->Command != SMB_COM_LOGOFF_ANDX)
			return -EAGAIN;
		/* else ok - we are shutting down session */
	}

	*ppmidQ = AllocMidQEntry(in_buf, ses->server);
	if (*ppmidQ == NULL)
		return -ENOMEM;
	spin_lock(&GlobalMid_Lock);
	list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
	spin_unlock(&GlobalMid_Lock);
	return 0;
}

static int
wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
{
	int error;

	error = wait_event_freezekillable_unsafe(server->response_q,
				    midQ->mid_state != MID_REQUEST_SUBMITTED);
	if (error < 0)
		return -ERESTARTSYS;

	return 0;
}

struct mid_q_entry *
cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
	int rc;
	struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
	struct mid_q_entry *mid;

	if (rqst->rq_iov[0].iov_len != 4 ||
	    rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
		return ERR_PTR(-EIO);

	/* enable signing if server requires it */
	if (server->sign)
		hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;

	mid = AllocMidQEntry(hdr, server);
	if (mid == NULL)
		return ERR_PTR(-ENOMEM);

	rc = cifs_sign_rqst(rqst, server, &mid->sequence_number);
	if (rc) {
		DeleteMidQEntry(mid);
		return ERR_PTR(rc);
	}

	return mid;
}

/*
 * Send a SMB request and set the callback function in the mid to handle
 * the result. Caller is responsible for dealing with timeouts.
 */
int
cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
		mid_receive_t *receive, mid_callback_t *callback,
		mid_handle_t *handle, void *cbdata, const int flags,
		const struct cifs_credits *exist_credits)
{
	int rc;
	struct mid_q_entry *mid;
	struct cifs_credits credits = { .value = 0, .instance = 0 };
	unsigned int instance;
	int optype;

	optype = flags & CIFS_OP_MASK;

	if ((flags & CIFS_HAS_CREDITS) == 0) {
		rc = wait_for_free_request(server, flags, &instance);
		if (rc)
			return rc;
		credits.value = 1;
		credits.instance = instance;
	} else
		instance = exist_credits->instance;

	mutex_lock(&server->srv_mutex);

	/*
	 * We can't use credits obtained from the previous session to send this
	 * request. Check if there were reconnects after we obtained credits and
	 * return -EAGAIN in such cases to let callers handle it.
	 */
	if (instance != server->reconnect_instance) {
		mutex_unlock(&server->srv_mutex);
		add_credits_and_wake_if(server, &credits, optype);
		return -EAGAIN;
	}

	mid = server->ops->setup_async_request(server, rqst);
	if (IS_ERR(mid)) {
		mutex_unlock(&server->srv_mutex);
		add_credits_and_wake_if(server, &credits, optype);
		return PTR_ERR(mid);
	}

	mid->receive = receive;
	mid->callback = callback;
	mid->callback_data = cbdata;
	mid->handle = handle;
	mid->mid_state = MID_REQUEST_SUBMITTED;

	/* put it on the pending_mid_q */
	spin_lock(&GlobalMid_Lock);
	list_add_tail(&mid->qhead, &server->pending_mid_q);
	spin_unlock(&GlobalMid_Lock);

	/*
	 * Need to store the time in mid before calling I/O. For call_async,
	 * I/O response may come back and free the mid entry on another thread.
	 */
	cifs_save_when_sent(mid);
	cifs_in_send_inc(server);
	rc = smb_send_rqst(server, 1, rqst, flags);
	cifs_in_send_dec(server);

	if (rc < 0) {
		revert_current_mid(server, mid->credits);
		server->sequence_number -= 2;
		cifs_delete_mid(mid);
	}

	mutex_unlock(&server->srv_mutex);

	if (rc == 0)
		return 0;

	add_credits_and_wake_if(server, &credits, optype);
	return rc;
}

/*
 *
 * Send an SMB Request.  No response info (other than return code)
 * needs to be parsed.
 *
 * flags indicate the type of request buffer and how long to wait
 * and whether to log NT STATUS code (error) before mapping it to POSIX error
 *
 */
int
SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
		 char *in_buf, int flags)
{
	int rc;
	struct kvec iov[1];
	struct kvec rsp_iov;
	int resp_buf_type;

	iov[0].iov_base = in_buf;
	iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
	flags |= CIFS_NO_RSP_BUF;
	rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags, &rsp_iov);
	cifs_dbg(NOISY, "SendRcvNoRsp flags %d rc %d\n", flags, rc);

	return rc;
}

static int
cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
{
	int rc = 0;

	cifs_dbg(FYI, "%s: cmd=%d mid=%llu state=%d\n",
		 __func__, le16_to_cpu(mid->command), mid->mid, mid->mid_state);

	spin_lock(&GlobalMid_Lock);
	switch (mid->mid_state) {
	case MID_RESPONSE_RECEIVED:
		spin_unlock(&GlobalMid_Lock);
		return rc;
	case MID_RETRY_NEEDED:
		rc = -EAGAIN;
		break;
	case MID_RESPONSE_MALFORMED:
		rc = -EIO;
		break;
	case MID_SHUTDOWN:
		rc = -EHOSTDOWN;
		break;
	default:
		if (!(mid->mid_flags & MID_DELETED)) {
			list_del_init(&mid->qhead);
			mid->mid_flags |= MID_DELETED;
		}
		cifs_server_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
			 __func__, mid->mid, mid->mid_state);
		rc = -EIO;
	}
	spin_unlock(&GlobalMid_Lock);

	DeleteMidQEntry(mid);
	return rc;
}

static inline int
send_cancel(struct TCP_Server_Info *server, struct smb_rqst *rqst,
	    struct mid_q_entry *mid)
{
	return server->ops->send_cancel ?
				server->ops->send_cancel(server, rqst, mid) : 0;
}

int
cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
		   bool log_error)
{
	unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;

	dump_smb(mid->resp_buf, min_t(u32, 92, len));

	/* convert the length into a more usable form */
	if (server->sign) {
		struct kvec iov[2];
		int rc = 0;
		struct smb_rqst rqst = { .rq_iov = iov,
					 .rq_nvec = 2 };

		iov[0].iov_base = mid->resp_buf;
		iov[0].iov_len = 4;
		iov[1].iov_base = (char *)mid->resp_buf + 4;
		iov[1].iov_len = len - 4;
		/* FIXME: add code to kill session */
		rc = cifs_verify_signature(&rqst, server,
					   mid->sequence_number);
		if (rc)
			cifs_server_dbg(VFS, "SMB signature verification returned error = %d\n",
				 rc);
	}

	/* BB special case reconnect tid and uid here? */
	return map_and_check_smb_error(mid, log_error);
}

struct mid_q_entry *
cifs_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *ignored,
		   struct smb_rqst *rqst)
{
	int rc;
	struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
	struct mid_q_entry *mid;

	if (rqst->rq_iov[0].iov_len != 4 ||
	    rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base)
		return ERR_PTR(-EIO);

	rc = allocate_mid(ses, hdr, &mid);
	if (rc)
		return ERR_PTR(rc);
	rc = cifs_sign_rqst(rqst, ses->server, &mid->sequence_number);
	if (rc) {
		cifs_delete_mid(mid);
		return ERR_PTR(rc);
	}
	return mid;
}

static void
cifs_compound_callback(struct mid_q_entry *mid)
{
	struct TCP_Server_Info *server = mid->server;
	struct cifs_credits credits;

	credits.value = server->ops->get_credits(mid);
	credits.instance = server->reconnect_instance;

	add_credits(server, &credits, mid->optype);
}

static void
cifs_compound_last_callback(struct mid_q_entry *mid)
{
	cifs_compound_callback(mid);
	cifs_wake_up_task(mid);
}

static void
cifs_cancelled_callback(struct mid_q_entry *mid)
{
	cifs_compound_callback(mid);
	DeleteMidQEntry(mid);
}

/*
 * Return a channel (master if none) of @ses that can be used to send
 * regular requests.
 *
 * If we are currently binding a new channel (negprot/sess.setup),
 * return the new incomplete channel.
 */
struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
{
	uint index = 0;

	if (!ses)
		return NULL;

	if (!ses->binding) {
		/* round robin */
		if (ses->chan_count > 1) {
			index = (uint)atomic_inc_return(&ses->chan_seq);
			index %= ses->chan_count;
		}
		return ses->chans[index].server;
	} else {
		return cifs_ses_server(ses);
	}
}

int
compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
		   struct TCP_Server_Info *server,
		   const int flags, const int num_rqst, struct smb_rqst *rqst,
		   int *resp_buf_type, struct kvec *resp_iov)
{
	int i, j, optype, rc = 0;
	struct mid_q_entry *midQ[MAX_COMPOUND];
	bool cancelled_mid[MAX_COMPOUND] = {false};
	struct cifs_credits credits[MAX_COMPOUND] = {
		{ .value = 0, .instance = 0 }
	};
	unsigned int instance;
	char *buf;

	optype = flags & CIFS_OP_MASK;

	for (i = 0; i < num_rqst; i++)
		resp_buf_type[i] = CIFS_NO_BUFFER;  /* no response buf yet */

	if (!ses || !ses->server || !server) {
		cifs_dbg(VFS, "Null session\n");
		return -EIO;
	}

	if (server->tcpStatus == CifsExiting)
		return -ENOENT;

	/*
	 * Wait for all the requests to become available.
	 * This approach still leaves the possibility to be stuck waiting for
	 * credits if the server doesn't grant credits to the outstanding
	 * requests and if the client is completely idle, not generating any
	 * other requests.
	 * This can be handled by the eventual session reconnect.
	 */
	rc = wait_for_compound_request(server, num_rqst, flags,
				       &instance);
	if (rc)
		return rc;

	for (i = 0; i < num_rqst; i++) {
		credits[i].value = 1;
		credits[i].instance = instance;
	}

	/*
	 * Make sure that we sign in the same order that we send on this socket
	 * and avoid races inside tcp sendmsg code that could cause corruption
	 * of smb data.
	 */

	mutex_lock(&server->srv_mutex);

	/*
	 * All the parts of the compound chain belong obtained credits from the
	 * same session. We can not use credits obtained from the previous
	 * session to send this request. Check if there were reconnects after
	 * we obtained credits and return -EAGAIN in such cases to let callers
	 * handle it.
	 */
	if (instance != server->reconnect_instance) {
		mutex_unlock(&server->srv_mutex);
		for (j = 0; j < num_rqst; j++)
			add_credits(server, &credits[j], optype);
		return -EAGAIN;
	}

	for (i = 0; i < num_rqst; i++) {
		midQ[i] = server->ops->setup_request(ses, server, &rqst[i]);
		if (IS_ERR(midQ[i])) {
			revert_current_mid(server, i);
			for (j = 0; j < i; j++)
				cifs_delete_mid(midQ[j]);
			mutex_unlock(&server->srv_mutex);

			/* Update # of requests on wire to server */
			for (j = 0; j < num_rqst; j++)
				add_credits(server, &credits[j], optype);
			return PTR_ERR(midQ[i]);
		}

		midQ[i]->mid_state = MID_REQUEST_SUBMITTED;
		midQ[i]->optype = optype;
		/*
		 * Invoke callback for every part of the compound chain
		 * to calculate credits properly. Wake up this thread only when
		 * the last element is received.
		 */
		if (i < num_rqst - 1)
			midQ[i]->callback = cifs_compound_callback;
		else
			midQ[i]->callback = cifs_compound_last_callback;
	}
	cifs_in_send_inc(server);
	rc = smb_send_rqst(server, num_rqst, rqst, flags);
	cifs_in_send_dec(server);

	for (i = 0; i < num_rqst; i++)
		cifs_save_when_sent(midQ[i]);

	if (rc < 0) {
		revert_current_mid(server, num_rqst);
		server->sequence_number -= 2;
	}

	mutex_unlock(&server->srv_mutex);

	/*
	 * If sending failed for some reason or it is an oplock break that we
	 * will not receive a response to - return credits back
	 */
	if (rc < 0 || (flags & CIFS_NO_SRV_RSP)) {
		for (i = 0; i < num_rqst; i++)
			add_credits(server, &credits[i], optype);
		goto out;
	}

	/*
	 * At this point the request is passed to the network stack - we assume
	 * that any credits taken from the server structure on the client have
	 * been spent and we can't return them back. Once we receive responses
	 * we will collect credits granted by the server in the mid callbacks
	 * and add those credits to the server structure.
	 */

	/*
	 * Compounding is never used during session establish.
	 */
	if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
		mutex_lock(&server->srv_mutex);
		smb311_update_preauth_hash(ses, rqst[0].rq_iov,
					   rqst[0].rq_nvec);
		mutex_unlock(&server->srv_mutex);
	}

	for (i = 0; i < num_rqst; i++) {
		rc = wait_for_response(server, midQ[i]);
		if (rc != 0)
			break;
	}
	if (rc != 0) {
		for (; i < num_rqst; i++) {
			cifs_server_dbg(FYI, "Cancelling wait for mid %llu cmd: %d\n",
				 midQ[i]->mid, le16_to_cpu(midQ[i]->command));
			send_cancel(server, &rqst[i], midQ[i]);
			spin_lock(&GlobalMid_Lock);
			midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
			if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
				midQ[i]->callback = cifs_cancelled_callback;
				cancelled_mid[i] = true;
				credits[i].value = 0;
			}
			spin_unlock(&GlobalMid_Lock);
		}
	}

	for (i = 0; i < num_rqst; i++) {
		if (rc < 0)
			goto out;

		rc = cifs_sync_mid_result(midQ[i], server);
		if (rc != 0) {
			/* mark this mid as cancelled to not free it below */
			cancelled_mid[i] = true;
			goto out;
		}

		if (!midQ[i]->resp_buf ||
		    midQ[i]->mid_state != MID_RESPONSE_RECEIVED) {
			rc = -EIO;
			cifs_dbg(FYI, "Bad MID state?\n");
			goto out;
		}

		buf = (char *)midQ[i]->resp_buf;
		resp_iov[i].iov_base = buf;
		resp_iov[i].iov_len = midQ[i]->resp_buf_size +
			server->vals->header_preamble_size;

		if (midQ[i]->large_buf)
			resp_buf_type[i] = CIFS_LARGE_BUFFER;
		else
			resp_buf_type[i] = CIFS_SMALL_BUFFER;

		rc = server->ops->check_receive(midQ[i], server,
						     flags & CIFS_LOG_ERROR);

		/* mark it so buf will not be freed by cifs_delete_mid */
		if ((flags & CIFS_NO_RSP_BUF) == 0)
			midQ[i]->resp_buf = NULL;

	}

	/*
	 * Compounding is never used during session establish.
	 */
	if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
		struct kvec iov = {
			.iov_base = resp_iov[0].iov_base,
			.iov_len = resp_iov[0].iov_len
		};
		mutex_lock(&server->srv_mutex);
		smb311_update_preauth_hash(ses, &iov, 1);
		mutex_unlock(&server->srv_mutex);
	}

out:
	/*
	 * This will dequeue all mids. After this it is important that the
	 * demultiplex_thread will not process any of these mids any futher.
	 * This is prevented above by using a noop callback that will not
	 * wake this thread except for the very last PDU.
	 */
	for (i = 0; i < num_rqst; i++) {
		if (!cancelled_mid[i])
			cifs_delete_mid(midQ[i]);
	}

	return rc;
}

int
cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
	       struct TCP_Server_Info *server,
	       struct smb_rqst *rqst, int *resp_buf_type, const int flags,
	       struct kvec *resp_iov)
{
	return compound_send_recv(xid, ses, server, flags, 1,
				  rqst, resp_buf_type, resp_iov);
}

int
SendReceive2(const unsigned int xid, struct cifs_ses *ses,
	     struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
	     const int flags, struct kvec *resp_iov)
{
	struct smb_rqst rqst;
	struct kvec s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
	int rc;

	if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
		new_iov = kmalloc_array(n_vec + 1, sizeof(struct kvec),
					GFP_KERNEL);
		if (!new_iov) {
			/* otherwise cifs_send_recv below sets resp_buf_type */
			*resp_buf_type = CIFS_NO_BUFFER;
			return -ENOMEM;
		}
	} else
		new_iov = s_iov;

	/* 1st iov is a RFC1001 length followed by the rest of the packet */
	memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec));

	new_iov[0].iov_base = new_iov[1].iov_base;
	new_iov[0].iov_len = 4;
	new_iov[1].iov_base += 4;
	new_iov[1].iov_len -= 4;

	memset(&rqst, 0, sizeof(struct smb_rqst));
	rqst.rq_iov = new_iov;
	rqst.rq_nvec = n_vec + 1;

	rc = cifs_send_recv(xid, ses, ses->server,
			    &rqst, resp_buf_type, flags, resp_iov);
	if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
		kfree(new_iov);
	return rc;
}

int
SendReceive(const unsigned int xid, struct cifs_ses *ses,
	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
	    int *pbytes_returned, const int flags)
{
	int rc = 0;
	struct mid_q_entry *midQ;
	unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
	struct kvec iov = { .iov_base = in_buf, .iov_len = len };
	struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
	struct cifs_credits credits = { .value = 1, .instance = 0 };
	struct TCP_Server_Info *server;

	if (ses == NULL) {
		cifs_dbg(VFS, "Null smb session\n");
		return -EIO;
	}
	server = ses->server;
	if (server == NULL) {
		cifs_dbg(VFS, "Null tcp session\n");
		return -EIO;
	}

	if (server->tcpStatus == CifsExiting)
		return -ENOENT;

	/* Ensure that we do not send more than 50 overlapping requests
	   to the same server. We may make this configurable later or
	   use ses->maxReq */

	if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
		cifs_server_dbg(VFS, "Invalid length, greater than maximum frame, %d\n",
				len);
		return -EIO;
	}

	rc = wait_for_free_request(server, flags, &credits.instance);
	if (rc)
		return rc;

	/* make sure that we sign in the same order that we send on this socket
	   and avoid races inside tcp sendmsg code that could cause corruption
	   of smb data */

	mutex_lock(&server->srv_mutex);

	rc = allocate_mid(ses, in_buf, &midQ);
	if (rc) {
		mutex_unlock(&server->srv_mutex);
		/* Update # of requests on wire to server */
		add_credits(server, &credits, 0);
		return rc;
	}

	rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
	if (rc) {
		mutex_unlock(&server->srv_mutex);
		goto out;
	}

	midQ->mid_state = MID_REQUEST_SUBMITTED;

	cifs_in_send_inc(server);
	rc = smb_send(server, in_buf, len);
	cifs_in_send_dec(server);
	cifs_save_when_sent(midQ);

	if (rc < 0)
		server->sequence_number -= 2;

	mutex_unlock(&server->srv_mutex);

	if (rc < 0)
		goto out;

	rc = wait_for_response(server, midQ);
	if (rc != 0) {
		send_cancel(server, &rqst, midQ);
		spin_lock(&GlobalMid_Lock);
		if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
			/* no longer considered to be "in-flight" */
			midQ->callback = DeleteMidQEntry;
			spin_unlock(&GlobalMid_Lock);
			add_credits(server, &credits, 0);
			return rc;
		}
		spin_unlock(&GlobalMid_Lock);
	}

	rc = cifs_sync_mid_result(midQ, server);
	if (rc != 0) {
		add_credits(server, &credits, 0);
		return rc;
	}

	if (!midQ->resp_buf || !out_buf ||
	    midQ->mid_state != MID_RESPONSE_RECEIVED) {
		rc = -EIO;
		cifs_server_dbg(VFS, "Bad MID state?\n");
		goto out;
	}

	*pbytes_returned = get_rfc1002_length(midQ->resp_buf);
	memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
	rc = cifs_check_receive(midQ, server, 0);
out:
	cifs_delete_mid(midQ);
	add_credits(server, &credits, 0);

	return rc;
}

/* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
   blocking lock to return. */

static int
send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
			struct smb_hdr *in_buf,
			struct smb_hdr *out_buf)
{
	int bytes_returned;
	struct cifs_ses *ses = tcon->ses;
	LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;

	/* We just modify the current in_buf to change
	   the type of lock from LOCKING_ANDX_SHARED_LOCK
	   or LOCKING_ANDX_EXCLUSIVE_LOCK to
	   LOCKING_ANDX_CANCEL_LOCK. */

	pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
	pSMB->Timeout = 0;
	pSMB->hdr.Mid = get_next_mid(ses->server);

	return SendReceive(xid, ses, in_buf, out_buf,
			&bytes_returned, 0);
}

int
SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
	    struct smb_hdr *in_buf, struct smb_hdr *out_buf,
	    int *pbytes_returned)
{
	int rc = 0;
	int rstart = 0;
	struct mid_q_entry *midQ;
	struct cifs_ses *ses;
	unsigned int len = be32_to_cpu(in_buf->smb_buf_length);
	struct kvec iov = { .iov_base = in_buf, .iov_len = len };
	struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 };
	unsigned int instance;
	struct TCP_Server_Info *server;

	if (tcon == NULL || tcon->ses == NULL) {
		cifs_dbg(VFS, "Null smb session\n");
		return -EIO;
	}
	ses = tcon->ses;
	server = ses->server;

	if (server == NULL) {
		cifs_dbg(VFS, "Null tcp session\n");
		return -EIO;
	}

	if (server->tcpStatus == CifsExiting)
		return -ENOENT;

	/* Ensure that we do not send more than 50 overlapping requests
	   to the same server. We may make this configurable later or
	   use ses->maxReq */

	if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
		cifs_tcon_dbg(VFS, "Invalid length, greater than maximum frame, %d\n",
			      len);
		return -EIO;
	}

	rc = wait_for_free_request(server, CIFS_BLOCKING_OP, &instance);
	if (rc)
		return rc;

	/* make sure that we sign in the same order that we send on this socket
	   and avoid races inside tcp sendmsg code that could cause corruption
	   of smb data */

	mutex_lock(&server->srv_mutex);

	rc = allocate_mid(ses, in_buf, &midQ);
	if (rc) {
		mutex_unlock(&server->srv_mutex);
		return rc;
	}

	rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
	if (rc) {
		cifs_delete_mid(midQ);
		mutex_unlock(&server->srv_mutex);
		return rc;
	}

	midQ->mid_state = MID_REQUEST_SUBMITTED;
	cifs_in_send_inc(server);
	rc = smb_send(server, in_buf, len);
	cifs_in_send_dec(server);
	cifs_save_when_sent(midQ);

	if (rc < 0)
		server->sequence_number -= 2;

	mutex_unlock(&server->srv_mutex);

	if (rc < 0) {
		cifs_delete_mid(midQ);
		return rc;
	}

	/* Wait for a reply - allow signals to interrupt. */
	rc = wait_event_interruptible(server->response_q,
		(!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
		((server->tcpStatus != CifsGood) &&
		 (server->tcpStatus != CifsNew)));

	/* Were we interrupted by a signal ? */
	if ((rc == -ERESTARTSYS) &&
		(midQ->mid_state == MID_REQUEST_SUBMITTED) &&
		((server->tcpStatus == CifsGood) ||
		 (server->tcpStatus == CifsNew))) {

		if (in_buf->Command == SMB_COM_TRANSACTION2) {
			/* POSIX lock. We send a NT_CANCEL SMB to cause the
			   blocking lock to return. */
			rc = send_cancel(server, &rqst, midQ);
			if (rc) {
				cifs_delete_mid(midQ);
				return rc;
			}
		} else {
			/* Windows lock. We send a LOCKINGX_CANCEL_LOCK
			   to cause the blocking lock to return. */

			rc = send_lock_cancel(xid, tcon, in_buf, out_buf);

			/* If we get -ENOLCK back the lock may have
			   already been removed. Don't exit in this case. */
			if (rc && rc != -ENOLCK) {
				cifs_delete_mid(midQ);
				return rc;
			}
		}

		rc = wait_for_response(server, midQ);
		if (rc) {
			send_cancel(server, &rqst, midQ);
			spin_lock(&GlobalMid_Lock);
			if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
				/* no longer considered to be "in-flight" */
				midQ->callback = DeleteMidQEntry;
				spin_unlock(&GlobalMid_Lock);
				return rc;
			}
			spin_unlock(&GlobalMid_Lock);
		}

		/* We got the response - restart system call. */
		rstart = 1;
	}

	rc = cifs_sync_mid_result(midQ, server);
	if (rc != 0)
		return rc;

	/* rcvd frame is ok */
	if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
		rc = -EIO;
		cifs_tcon_dbg(VFS, "Bad MID state?\n");
		goto out;
	}

	*pbytes_returned = get_rfc1002_length(midQ->resp_buf);
	memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
	rc = cifs_check_receive(midQ, server, 0);
out:
	cifs_delete_mid(midQ);
	if (rstart && rc == -EACCES)
		return -ERESTARTSYS;
	return rc;
}