summaryrefslogtreecommitdiffstats
path: root/drivers/usb/storage/uas.c
blob: d002eead62b4b3dfe01d3d12b7ff9e35f0e11adb (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
// SPDX-License-Identifier: GPL-2.0
/*
 * USB Attached SCSI
 * Note that this is not the same as the USB Mass Storage driver
 *
 * Copyright Hans de Goede <hdegoede@redhat.com> for Red Hat, Inc. 2013 - 2016
 * Copyright Matthew Wilcox for Intel Corp, 2010
 * Copyright Sarah Sharp for Intel Corp, 2010
 */

#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb_usual.h>
#include <linux/usb/hcd.h>
#include <linux/usb/storage.h>
#include <linux/usb/uas.h>

#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>

#include "uas-detect.h"
#include "scsiglue.h"

#define MAX_CMNDS 256

struct uas_dev_info {
	struct usb_interface *intf;
	struct usb_device *udev;
	struct usb_anchor cmd_urbs;
	struct usb_anchor sense_urbs;
	struct usb_anchor data_urbs;
	u64 flags;
	int qdepth, resetting;
	unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
	unsigned use_streams:1;
	unsigned shutdown:1;
	struct scsi_cmnd *cmnd[MAX_CMNDS];
	spinlock_t lock;
	struct work_struct work;
	struct work_struct scan_work;      /* for async scanning */
};

enum {
	SUBMIT_STATUS_URB	= BIT(1),
	ALLOC_DATA_IN_URB	= BIT(2),
	SUBMIT_DATA_IN_URB	= BIT(3),
	ALLOC_DATA_OUT_URB	= BIT(4),
	SUBMIT_DATA_OUT_URB	= BIT(5),
	ALLOC_CMD_URB		= BIT(6),
	SUBMIT_CMD_URB		= BIT(7),
	COMMAND_INFLIGHT        = BIT(8),
	DATA_IN_URB_INFLIGHT    = BIT(9),
	DATA_OUT_URB_INFLIGHT   = BIT(10),
	COMMAND_ABORTED         = BIT(11),
	IS_IN_WORK_LIST         = BIT(12),
};

/* Overrides scsi_pointer */
struct uas_cmd_info {
	unsigned int state;
	unsigned int uas_tag;
	struct urb *cmd_urb;
	struct urb *data_in_urb;
	struct urb *data_out_urb;
};

/* I hate forward declarations, but I actually have a loop */
static int uas_submit_urbs(struct scsi_cmnd *cmnd,
				struct uas_dev_info *devinfo);
static void uas_do_work(struct work_struct *work);
static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller);
static void uas_free_streams(struct uas_dev_info *devinfo);
static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *prefix,
				int status);

/*
 * This driver needs its own workqueue, as we need to control memory allocation.
 *
 * In the course of error handling and power management uas_wait_for_pending_cmnds()
 * needs to flush pending work items. In these contexts we cannot allocate memory
 * by doing block IO as we would deadlock. For the same reason we cannot wait
 * for anything allocating memory not heeding these constraints.
 *
 * So we have to control all work items that can be on the workqueue we flush.
 * Hence we cannot share a queue and need our own.
 */
static struct workqueue_struct *workqueue;

static void uas_do_work(struct work_struct *work)
{
	struct uas_dev_info *devinfo =
		container_of(work, struct uas_dev_info, work);
	struct uas_cmd_info *cmdinfo;
	struct scsi_cmnd *cmnd;
	unsigned long flags;
	int i, err;

	spin_lock_irqsave(&devinfo->lock, flags);

	if (devinfo->resetting)
		goto out;

	for (i = 0; i < devinfo->qdepth; i++) {
		if (!devinfo->cmnd[i])
			continue;

		cmnd = devinfo->cmnd[i];
		cmdinfo = scsi_cmd_priv(cmnd);

		if (!(cmdinfo->state & IS_IN_WORK_LIST))
			continue;

		err = uas_submit_urbs(cmnd, cmnd->device->hostdata);
		if (!err)
			cmdinfo->state &= ~IS_IN_WORK_LIST;
		else
			queue_work(workqueue, &devinfo->work);
	}
out:
	spin_unlock_irqrestore(&devinfo->lock, flags);
}

static void uas_scan_work(struct work_struct *work)
{
	struct uas_dev_info *devinfo =
		container_of(work, struct uas_dev_info, scan_work);
	struct Scsi_Host *shost = usb_get_intfdata(devinfo->intf);

	dev_dbg(&devinfo->intf->dev, "starting scan\n");
	scsi_scan_host(shost);
	dev_dbg(&devinfo->intf->dev, "scan complete\n");
}

static void uas_add_work(struct scsi_cmnd *cmnd)
{
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct uas_dev_info *devinfo = cmnd->device->hostdata;

	lockdep_assert_held(&devinfo->lock);
	cmdinfo->state |= IS_IN_WORK_LIST;
	queue_work(workqueue, &devinfo->work);
}

static void uas_zap_pending(struct uas_dev_info *devinfo, int result)
{
	struct uas_cmd_info *cmdinfo;
	struct scsi_cmnd *cmnd;
	unsigned long flags;
	int i, err;

	spin_lock_irqsave(&devinfo->lock, flags);
	for (i = 0; i < devinfo->qdepth; i++) {
		if (!devinfo->cmnd[i])
			continue;

		cmnd = devinfo->cmnd[i];
		cmdinfo = scsi_cmd_priv(cmnd);
		uas_log_cmd_state(cmnd, __func__, 0);
		/* Sense urbs were killed, clear COMMAND_INFLIGHT manually */
		cmdinfo->state &= ~COMMAND_INFLIGHT;
		cmnd->result = result << 16;
		err = uas_try_complete(cmnd, __func__);
		WARN_ON(err != 0);
	}
	spin_unlock_irqrestore(&devinfo->lock, flags);
}

static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
{
	struct sense_iu *sense_iu = urb->transfer_buffer;
	struct scsi_device *sdev = cmnd->device;

	if (urb->actual_length > 16) {
		unsigned len = be16_to_cpup(&sense_iu->len);
		if (len + 16 != urb->actual_length) {
			int newlen = min(len + 16, urb->actual_length) - 16;
			if (newlen < 0)
				newlen = 0;
			sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
				"disagrees with IU sense data length %d, "
				"using %d bytes of sense data\n", __func__,
					urb->actual_length, len, newlen);
			len = newlen;
		}
		memcpy(cmnd->sense_buffer, sense_iu->sense, len);
	}

	cmnd->result = sense_iu->status;
}

static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *prefix,
			      int status)
{
	struct uas_cmd_info *ci = scsi_cmd_priv(cmnd);

	if (status == -ENODEV) /* too late */
		return;

	scmd_printk(KERN_INFO, cmnd,
		    "%s %d uas-tag %d inflight:%s%s%s%s%s%s%s%s%s%s%s%s ",
		    prefix, status, ci->uas_tag,
		    (ci->state & SUBMIT_STATUS_URB)     ? " s-st"  : "",
		    (ci->state & ALLOC_DATA_IN_URB)     ? " a-in"  : "",
		    (ci->state & SUBMIT_DATA_IN_URB)    ? " s-in"  : "",
		    (ci->state & ALLOC_DATA_OUT_URB)    ? " a-out" : "",
		    (ci->state & SUBMIT_DATA_OUT_URB)   ? " s-out" : "",
		    (ci->state & ALLOC_CMD_URB)         ? " a-cmd" : "",
		    (ci->state & SUBMIT_CMD_URB)        ? " s-cmd" : "",
		    (ci->state & COMMAND_INFLIGHT)      ? " CMD"   : "",
		    (ci->state & DATA_IN_URB_INFLIGHT)  ? " IN"    : "",
		    (ci->state & DATA_OUT_URB_INFLIGHT) ? " OUT"   : "",
		    (ci->state & COMMAND_ABORTED)       ? " abort" : "",
		    (ci->state & IS_IN_WORK_LIST)       ? " work"  : "");
	scsi_print_command(cmnd);
}

static void uas_free_unsubmitted_urbs(struct scsi_cmnd *cmnd)
{
	struct uas_cmd_info *cmdinfo;

	if (!cmnd)
		return;

	cmdinfo = scsi_cmd_priv(cmnd);

	if (cmdinfo->state & SUBMIT_CMD_URB)
		usb_free_urb(cmdinfo->cmd_urb);

	/* data urbs may have never gotten their submit flag set */
	if (!(cmdinfo->state & DATA_IN_URB_INFLIGHT))
		usb_free_urb(cmdinfo->data_in_urb);
	if (!(cmdinfo->state & DATA_OUT_URB_INFLIGHT))
		usb_free_urb(cmdinfo->data_out_urb);
}

static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller)
{
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;

	lockdep_assert_held(&devinfo->lock);
	if (cmdinfo->state & (COMMAND_INFLIGHT |
			      DATA_IN_URB_INFLIGHT |
			      DATA_OUT_URB_INFLIGHT |
			      COMMAND_ABORTED))
		return -EBUSY;
	devinfo->cmnd[cmdinfo->uas_tag - 1] = NULL;
	uas_free_unsubmitted_urbs(cmnd);
	scsi_done(cmnd);
	return 0;
}

static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
			  unsigned direction)
{
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	int err;

	cmdinfo->state |= direction | SUBMIT_STATUS_URB;
	err = uas_submit_urbs(cmnd, cmnd->device->hostdata);
	if (err) {
		uas_add_work(cmnd);
	}
}

static bool uas_evaluate_response_iu(struct response_iu *riu, struct scsi_cmnd *cmnd)
{
	u8 response_code = riu->response_code;

	switch (response_code) {
	case RC_INCORRECT_LUN:
		set_host_byte(cmnd, DID_BAD_TARGET);
		break;
	case RC_TMF_SUCCEEDED:
		set_host_byte(cmnd, DID_OK);
		break;
	case RC_TMF_NOT_SUPPORTED:
		set_host_byte(cmnd, DID_BAD_TARGET);
		break;
	default:
		uas_log_cmd_state(cmnd, "response iu", response_code);
		set_host_byte(cmnd, DID_ERROR);
		break;
	}

	return response_code == RC_TMF_SUCCEEDED;
}

static void uas_stat_cmplt(struct urb *urb)
{
	struct iu *iu = urb->transfer_buffer;
	struct Scsi_Host *shost = urb->context;
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
	struct urb *data_in_urb = NULL;
	struct urb *data_out_urb = NULL;
	struct scsi_cmnd *cmnd;
	struct uas_cmd_info *cmdinfo;
	unsigned long flags;
	unsigned int idx;
	int status = urb->status;
	bool success;

	spin_lock_irqsave(&devinfo->lock, flags);

	if (devinfo->resetting)
		goto out;

	if (status) {
		if (status != -ENOENT && status != -ECONNRESET && status != -ESHUTDOWN)
			dev_err(&urb->dev->dev, "stat urb: status %d\n", status);
		goto out;
	}

	idx = be16_to_cpup(&iu->tag) - 1;
	if (idx >= MAX_CMNDS || !devinfo->cmnd[idx]) {
		dev_err(&urb->dev->dev,
			"stat urb: no pending cmd for uas-tag %d\n", idx + 1);
		goto out;
	}

	cmnd = devinfo->cmnd[idx];
	cmdinfo = scsi_cmd_priv(cmnd);

	if (!(cmdinfo->state & COMMAND_INFLIGHT)) {
		uas_log_cmd_state(cmnd, "unexpected status cmplt", 0);
		goto out;
	}

	switch (iu->iu_id) {
	case IU_ID_STATUS:
		uas_sense(urb, cmnd);
		if (cmnd->result != 0) {
			/* cancel data transfers on error */
			data_in_urb = usb_get_urb(cmdinfo->data_in_urb);
			data_out_urb = usb_get_urb(cmdinfo->data_out_urb);
		}
		cmdinfo->state &= ~COMMAND_INFLIGHT;
		uas_try_complete(cmnd, __func__);
		break;
	case IU_ID_READ_READY:
		if (!cmdinfo->data_in_urb ||
				(cmdinfo->state & DATA_IN_URB_INFLIGHT)) {
			uas_log_cmd_state(cmnd, "unexpected read rdy", 0);
			break;
		}
		uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
		break;
	case IU_ID_WRITE_READY:
		if (!cmdinfo->data_out_urb ||
				(cmdinfo->state & DATA_OUT_URB_INFLIGHT)) {
			uas_log_cmd_state(cmnd, "unexpected write rdy", 0);
			break;
		}
		uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
		break;
	case IU_ID_RESPONSE:
		cmdinfo->state &= ~COMMAND_INFLIGHT;
		success = uas_evaluate_response_iu((struct response_iu *)iu, cmnd);
		if (!success) {
			/* Error, cancel data transfers */
			data_in_urb = usb_get_urb(cmdinfo->data_in_urb);
			data_out_urb = usb_get_urb(cmdinfo->data_out_urb);
		}
		uas_try_complete(cmnd, __func__);
		break;
	default:
		uas_log_cmd_state(cmnd, "bogus IU", iu->iu_id);
	}
out:
	usb_free_urb(urb);
	spin_unlock_irqrestore(&devinfo->lock, flags);

	/* Unlinking of data urbs must be done without holding the lock */
	if (data_in_urb) {
		usb_unlink_urb(data_in_urb);
		usb_put_urb(data_in_urb);
	}
	if (data_out_urb) {
		usb_unlink_urb(data_out_urb);
		usb_put_urb(data_out_urb);
	}
}

static void uas_data_cmplt(struct urb *urb)
{
	struct scsi_cmnd *cmnd = urb->context;
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;
	struct scsi_data_buffer *sdb = &cmnd->sdb;
	unsigned long flags;
	int status = urb->status;

	spin_lock_irqsave(&devinfo->lock, flags);

	if (cmdinfo->data_in_urb == urb) {
		cmdinfo->state &= ~DATA_IN_URB_INFLIGHT;
		cmdinfo->data_in_urb = NULL;
	} else if (cmdinfo->data_out_urb == urb) {
		cmdinfo->state &= ~DATA_OUT_URB_INFLIGHT;
		cmdinfo->data_out_urb = NULL;
	}

	if (devinfo->resetting)
		goto out;

	/* Data urbs should not complete before the cmd urb is submitted */
	if (cmdinfo->state & SUBMIT_CMD_URB) {
		uas_log_cmd_state(cmnd, "unexpected data cmplt", 0);
		goto out;
	}

	if (status) {
		if (status != -ENOENT && status != -ECONNRESET && status != -ESHUTDOWN)
			uas_log_cmd_state(cmnd, "data cmplt err", status);
		/* error: no data transfered */
		scsi_set_resid(cmnd, sdb->length);
	} else {
		scsi_set_resid(cmnd, sdb->length - urb->actual_length);
	}
	uas_try_complete(cmnd, __func__);
out:
	usb_free_urb(urb);
	spin_unlock_irqrestore(&devinfo->lock, flags);
}

static void uas_cmd_cmplt(struct urb *urb)
{
	if (urb->status)
		dev_err(&urb->dev->dev, "cmd cmplt err %d\n", urb->status);

	usb_free_urb(urb);
}

static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
				      struct scsi_cmnd *cmnd,
				      enum dma_data_direction dir)
{
	struct usb_device *udev = devinfo->udev;
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct urb *urb = usb_alloc_urb(0, gfp);
	struct scsi_data_buffer *sdb = &cmnd->sdb;
	unsigned int pipe = (dir == DMA_FROM_DEVICE)
		? devinfo->data_in_pipe : devinfo->data_out_pipe;

	if (!urb)
		goto out;
	usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length,
			  uas_data_cmplt, cmnd);
	if (devinfo->use_streams)
		urb->stream_id = cmdinfo->uas_tag;
	urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
	urb->sg = sdb->table.sgl;
 out:
	return urb;
}

static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
				       struct scsi_cmnd *cmnd)
{
	struct usb_device *udev = devinfo->udev;
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct urb *urb = usb_alloc_urb(0, gfp);
	struct sense_iu *iu;

	if (!urb)
		goto out;

	iu = kzalloc(sizeof(*iu), gfp);
	if (!iu)
		goto free;

	usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
			  uas_stat_cmplt, cmnd->device->host);
	if (devinfo->use_streams)
		urb->stream_id = cmdinfo->uas_tag;
	urb->transfer_flags |= URB_FREE_BUFFER;
 out:
	return urb;
 free:
	usb_free_urb(urb);
	return NULL;
}

static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
					struct scsi_cmnd *cmnd)
{
	struct usb_device *udev = devinfo->udev;
	struct scsi_device *sdev = cmnd->device;
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct urb *urb = usb_alloc_urb(0, gfp);
	struct command_iu *iu;
	int len;

	if (!urb)
		goto out;

	len = cmnd->cmd_len - 16;
	if (len < 0)
		len = 0;
	len = ALIGN(len, 4);
	iu = kzalloc(sizeof(*iu) + len, gfp);
	if (!iu)
		goto free;

	iu->iu_id = IU_ID_COMMAND;
	iu->tag = cpu_to_be16(cmdinfo->uas_tag);
	iu->prio_attr = UAS_SIMPLE_TAG;
	iu->len = len;
	int_to_scsilun(sdev->lun, &iu->lun);
	memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);

	usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
							uas_cmd_cmplt, NULL);
	urb->transfer_flags |= URB_FREE_BUFFER;
 out:
	return urb;
 free:
	usb_free_urb(urb);
	return NULL;
}

/*
 * Why should I request the Status IU before sending the Command IU?  Spec
 * says to, but also says the device may receive them in any order.  Seems
 * daft to me.
 */

static int uas_submit_sense_urb(struct scsi_cmnd *cmnd, gfp_t gfp)
{
	struct uas_dev_info *devinfo = cmnd->device->hostdata;
	struct urb *urb;
	int err;

	urb = uas_alloc_sense_urb(devinfo, gfp, cmnd);
	if (!urb)
		return -ENOMEM;
	usb_anchor_urb(urb, &devinfo->sense_urbs);
	err = usb_submit_urb(urb, gfp);
	if (err) {
		usb_unanchor_urb(urb);
		uas_log_cmd_state(cmnd, "sense submit err", err);
		usb_free_urb(urb);
	}
	return err;
}

static int uas_submit_urbs(struct scsi_cmnd *cmnd,
			   struct uas_dev_info *devinfo)
{
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	int err;

	lockdep_assert_held(&devinfo->lock);
	if (cmdinfo->state & SUBMIT_STATUS_URB) {
		err = uas_submit_sense_urb(cmnd, GFP_ATOMIC);
		if (err)
			return err;
		cmdinfo->state &= ~SUBMIT_STATUS_URB;
	}

	if (cmdinfo->state & ALLOC_DATA_IN_URB) {
		cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, GFP_ATOMIC,
							cmnd, DMA_FROM_DEVICE);
		if (!cmdinfo->data_in_urb)
			return -ENOMEM;
		cmdinfo->state &= ~ALLOC_DATA_IN_URB;
	}

	if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
		usb_anchor_urb(cmdinfo->data_in_urb, &devinfo->data_urbs);
		err = usb_submit_urb(cmdinfo->data_in_urb, GFP_ATOMIC);
		if (err) {
			usb_unanchor_urb(cmdinfo->data_in_urb);
			uas_log_cmd_state(cmnd, "data in submit err", err);
			return err;
		}
		cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
		cmdinfo->state |= DATA_IN_URB_INFLIGHT;
	}

	if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
		cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, GFP_ATOMIC,
							cmnd, DMA_TO_DEVICE);
		if (!cmdinfo->data_out_urb)
			return -ENOMEM;
		cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
	}

	if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
		usb_anchor_urb(cmdinfo->data_out_urb, &devinfo->data_urbs);
		err = usb_submit_urb(cmdinfo->data_out_urb, GFP_ATOMIC);
		if (err) {
			usb_unanchor_urb(cmdinfo->data_out_urb);
			uas_log_cmd_state(cmnd, "data out submit err", err);
			return err;
		}
		cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
		cmdinfo->state |= DATA_OUT_URB_INFLIGHT;
	}

	if (cmdinfo->state & ALLOC_CMD_URB) {
		cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, GFP_ATOMIC, cmnd);
		if (!cmdinfo->cmd_urb)
			return -ENOMEM;
		cmdinfo->state &= ~ALLOC_CMD_URB;
	}

	if (cmdinfo->state & SUBMIT_CMD_URB) {
		usb_anchor_urb(cmdinfo->cmd_urb, &devinfo->cmd_urbs);
		err = usb_submit_urb(cmdinfo->cmd_urb, GFP_ATOMIC);
		if (err) {
			usb_unanchor_urb(cmdinfo->cmd_urb);
			uas_log_cmd_state(cmnd, "cmd submit err", err);
			return err;
		}
		cmdinfo->cmd_urb = NULL;
		cmdinfo->state &= ~SUBMIT_CMD_URB;
		cmdinfo->state |= COMMAND_INFLIGHT;
	}

	return 0;
}

static int uas_queuecommand_lck(struct scsi_cmnd *cmnd)
{
	struct scsi_device *sdev = cmnd->device;
	struct uas_dev_info *devinfo = sdev->hostdata;
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	unsigned long flags;
	int idx, err;

	/* Re-check scsi_block_requests now that we've the host-lock */
	if (cmnd->device->host->host_self_blocked)
		return SCSI_MLQUEUE_DEVICE_BUSY;

	if ((devinfo->flags & US_FL_NO_ATA_1X) &&
			(cmnd->cmnd[0] == ATA_12 || cmnd->cmnd[0] == ATA_16)) {
		memcpy(cmnd->sense_buffer, usb_stor_sense_invalidCDB,
		       sizeof(usb_stor_sense_invalidCDB));
		cmnd->result = SAM_STAT_CHECK_CONDITION;
		scsi_done(cmnd);
		return 0;
	}

	spin_lock_irqsave(&devinfo->lock, flags);

	if (devinfo->resetting) {
		set_host_byte(cmnd, DID_ERROR);
		scsi_done(cmnd);
		goto zombie;
	}

	/* Find a free uas-tag */
	for (idx = 0; idx < devinfo->qdepth; idx++) {
		if (!devinfo->cmnd[idx])
			break;
	}
	if (idx == devinfo->qdepth) {
		spin_unlock_irqrestore(&devinfo->lock, flags);
		return SCSI_MLQUEUE_DEVICE_BUSY;
	}

	memset(cmdinfo, 0, sizeof(*cmdinfo));
	cmdinfo->uas_tag = idx + 1; /* uas-tag == usb-stream-id, so 1 based */
	cmdinfo->state = SUBMIT_STATUS_URB | ALLOC_CMD_URB | SUBMIT_CMD_URB;

	switch (cmnd->sc_data_direction) {
	case DMA_FROM_DEVICE:
		cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
		break;
	case DMA_BIDIRECTIONAL:
		cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
		fallthrough;
	case DMA_TO_DEVICE:
		cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
		break;
	case DMA_NONE:
		break;
	}

	if (!devinfo->use_streams)
		cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB);

	err = uas_submit_urbs(cmnd, devinfo);
	/*
	 * in case of fatal errors the SCSI layer is peculiar
	 * a command that has finished is a success for the purpose
	 * of queueing, no matter how fatal the error
	 */
	if (err == -ENODEV) {
		set_host_byte(cmnd, DID_NO_CONNECT);
		scsi_done(cmnd);
		goto zombie;
	}
	if (err) {
		/* If we did nothing, give up now */
		if (cmdinfo->state & SUBMIT_STATUS_URB) {
			spin_unlock_irqrestore(&devinfo->lock, flags);
			return SCSI_MLQUEUE_DEVICE_BUSY;
		}
		uas_add_work(cmnd);
	}

	devinfo->cmnd[idx] = cmnd;
zombie:
	spin_unlock_irqrestore(&devinfo->lock, flags);
	return 0;
}

static DEF_SCSI_QCMD(uas_queuecommand)

/*
 * For now we do not support actually sending an abort to the device, so
 * this eh always fails. Still we must define it to make sure that we've
 * dropped all references to the cmnd in question once this function exits.
 */
static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
{
	struct uas_cmd_info *cmdinfo = scsi_cmd_priv(cmnd);
	struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;
	struct urb *data_in_urb = NULL;
	struct urb *data_out_urb = NULL;
	unsigned long flags;

	spin_lock_irqsave(&devinfo->lock, flags);

	uas_log_cmd_state(cmnd, __func__, 0);

	/* Ensure that try_complete does not call scsi_done */
	cmdinfo->state |= COMMAND_ABORTED;

	/* Drop all refs to this cmnd, kill data urbs to break their ref */
	devinfo->cmnd[cmdinfo->uas_tag - 1] = NULL;
	if (cmdinfo->state & DATA_IN_URB_INFLIGHT)
		data_in_urb = usb_get_urb(cmdinfo->data_in_urb);
	if (cmdinfo->state & DATA_OUT_URB_INFLIGHT)
		data_out_urb = usb_get_urb(cmdinfo->data_out_urb);

	uas_free_unsubmitted_urbs(cmnd);

	spin_unlock_irqrestore(&devinfo->lock, flags);

	if (data_in_urb) {
		usb_kill_urb(data_in_urb);
		usb_put_urb(data_in_urb);
	}
	if (data_out_urb) {
		usb_kill_urb(data_out_urb);
		usb_put_urb(data_out_urb);
	}

	return FAILED;
}

static int uas_eh_device_reset_handler(struct scsi_cmnd *cmnd)
{
	struct scsi_device *sdev = cmnd->device;
	struct uas_dev_info *devinfo = sdev->hostdata;
	struct usb_device *udev = devinfo->udev;
	unsigned long flags;
	int err;

	err = usb_lock_device_for_reset(udev, devinfo->intf);
	if (err) {
		shost_printk(KERN_ERR, sdev->host,
			     "%s FAILED to get lock err %d\n", __func__, err);
		return FAILED;
	}

	shost_printk(KERN_INFO, sdev->host, "%s start\n", __func__);

	spin_lock_irqsave(&devinfo->lock, flags);
	devinfo->resetting = 1;
	spin_unlock_irqrestore(&devinfo->lock, flags);

	usb_kill_anchored_urbs(&devinfo->cmd_urbs);
	usb_kill_anchored_urbs(&devinfo->sense_urbs);
	usb_kill_anchored_urbs(&devinfo->data_urbs);
	uas_zap_pending(devinfo, DID_RESET);

	err = usb_reset_device(udev);

	spin_lock_irqsave(&devinfo->lock, flags);
	devinfo->resetting = 0;
	spin_unlock_irqrestore(&devinfo->lock, flags);

	usb_unlock_device(udev);

	if (err) {
		shost_printk(KERN_INFO, sdev->host, "%s FAILED err %d\n",
			     __func__, err);
		return FAILED;
	}

	shost_printk(KERN_INFO, sdev->host, "%s success\n", __func__);
	return SUCCESS;
}

static int uas_target_alloc(struct scsi_target *starget)
{
	struct uas_dev_info *devinfo = (struct uas_dev_info *)
			dev_to_shost(starget->dev.parent)->hostdata;

	if (devinfo->flags & US_FL_NO_REPORT_LUNS)
		starget->no_report_luns = 1;

	return 0;
}

static int uas_slave_alloc(struct scsi_device *sdev)
{
	struct uas_dev_info *devinfo =
		(struct uas_dev_info *)sdev->host->hostdata;

	sdev->hostdata = devinfo;

	/*
	 * The protocol has no requirements on alignment in the strict sense.
	 * Controllers may or may not have alignment restrictions.
	 * As this is not exported, we use an extremely conservative guess.
	 */
	blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));

	if (devinfo->flags & US_FL_MAX_SECTORS_64)
		blk_queue_max_hw_sectors(sdev->request_queue, 64);
	else if (devinfo->flags & US_FL_MAX_SECTORS_240)
		blk_queue_max_hw_sectors(sdev->request_queue, 240);

	return 0;
}

static int uas_slave_configure(struct scsi_device *sdev)
{
	struct uas_dev_info *devinfo = sdev->hostdata;

	if (devinfo->flags & US_FL_NO_REPORT_OPCODES)
		sdev->no_report_opcodes = 1;

	/* A few buggy USB-ATA bridges don't understand FUA */
	if (devinfo->flags & US_FL_BROKEN_FUA)
		sdev->broken_fua = 1;

	/* UAS also needs to support FL_ALWAYS_SYNC */
	if (devinfo->flags & US_FL_ALWAYS_SYNC) {
		sdev->skip_ms_page_3f = 1;
		sdev->skip_ms_page_8 = 1;
		sdev->wce_default_on = 1;
	}

	/* Some disks cannot handle READ_CAPACITY_16 */
	if (devinfo->flags & US_FL_NO_READ_CAPACITY_16)
		sdev->no_read_capacity_16 = 1;

	/* Some disks cannot handle WRITE_SAME */
	if (devinfo->flags & US_FL_NO_SAME)
		sdev->no_write_same = 1;
	/*
	 * Some disks return the total number of blocks in response
	 * to READ CAPACITY rather than the highest block number.
	 * If this device makes that mistake, tell the sd driver.
	 */
	if (devinfo->flags & US_FL_FIX_CAPACITY)
		sdev->fix_capacity = 1;

	/*
	 * in some cases we have to guess
	 */
	if (devinfo->flags & US_FL_CAPACITY_HEURISTICS)
		sdev->guess_capacity = 1;

	/*
	 * Some devices report generic values until the media has been
	 * accessed. Force a READ(10) prior to querying device
	 * characteristics.
	 */
	sdev->read_before_ms = 1;

	/*
	 * Some devices don't like MODE SENSE with page=0x3f,
	 * which is the command used for checking if a device
	 * is write-protected.  Now that we tell the sd driver
	 * to do a 192-byte transfer with this command the
	 * majority of devices work fine, but a few still can't
	 * handle it.  The sd driver will simply assume those
	 * devices are write-enabled.
	 */
	if (devinfo->flags & US_FL_NO_WP_DETECT)
		sdev->skip_ms_page_3f = 1;

	scsi_change_queue_depth(sdev, devinfo->qdepth - 2);
	return 0;
}

static const struct scsi_host_template uas_host_template = {
	.module = THIS_MODULE,
	.name = "uas",
	.queuecommand = uas_queuecommand,
	.target_alloc = uas_target_alloc,
	.slave_alloc = uas_slave_alloc,
	.slave_configure = uas_slave_configure,
	.eh_abort_handler = uas_eh_abort_handler,
	.eh_device_reset_handler = uas_eh_device_reset_handler,
	.this_id = -1,
	.skip_settle_delay = 1,
	.dma_boundary = PAGE_SIZE - 1,
	.cmd_size = sizeof(struct uas_cmd_info),
};

#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
		    vendorName, productName, useProtocol, useTransport, \
		    initFunction, flags) \
{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax), \
	.driver_info = (flags) }

static struct usb_device_id uas_usb_ids[] = {
#	include "unusual_uas.h"
	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
	{ }
};
MODULE_DEVICE_TABLE(usb, uas_usb_ids);

#undef UNUSUAL_DEV

static int uas_switch_interface(struct usb_device *udev,
				struct usb_interface *intf)
{
	struct usb_host_interface *alt;

	alt = uas_find_uas_alt_setting(intf);
	if (!alt)
		return -ENODEV;

	return usb_set_interface(udev, alt->desc.bInterfaceNumber,
			alt->desc.bAlternateSetting);
}

static int uas_configure_endpoints(struct uas_dev_info *devinfo)
{
	struct usb_host_endpoint *eps[4] = { };
	struct usb_device *udev = devinfo->udev;
	int r;

	r = uas_find_endpoints(devinfo->intf->cur_altsetting, eps);
	if (r)
		return r;

	devinfo->cmd_pipe = usb_sndbulkpipe(udev,
					    usb_endpoint_num(&eps[0]->desc));
	devinfo->status_pipe = usb_rcvbulkpipe(udev,
					    usb_endpoint_num(&eps[1]->desc));
	devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
					    usb_endpoint_num(&eps[2]->desc));
	devinfo->data_out_pipe = usb_sndbulkpipe(udev,
					    usb_endpoint_num(&eps[3]->desc));

	if (udev->speed < USB_SPEED_SUPER) {
		devinfo->qdepth = 32;
		devinfo->use_streams = 0;
	} else {
		devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1,
						    3, MAX_CMNDS, GFP_NOIO);
		if (devinfo->qdepth < 0)
			return devinfo->qdepth;
		devinfo->use_streams = 1;
	}

	return 0;
}

static void uas_free_streams(struct uas_dev_info *devinfo)
{
	struct usb_device *udev = devinfo->udev;
	struct usb_host_endpoint *eps[3];

	eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
	eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
	eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
	usb_free_streams(devinfo->intf, eps, 3, GFP_NOIO);
}

static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
	int result = -ENOMEM;
	struct Scsi_Host *shost = NULL;
	struct uas_dev_info *devinfo;
	struct usb_device *udev = interface_to_usbdev(intf);
	u64 dev_flags;

	if (!uas_use_uas_driver(intf, id, &dev_flags))
		return -ENODEV;

	if (uas_switch_interface(udev, intf))
		return -ENODEV;

	shost = scsi_host_alloc(&uas_host_template,
				sizeof(struct uas_dev_info));
	if (!shost)
		goto set_alt0;

	shost->max_cmd_len = 16 + 252;
	shost->max_id = 1;
	shost->max_lun = 256;
	shost->max_channel = 0;
	shost->sg_tablesize = udev->bus->sg_tablesize;

	devinfo = (struct uas_dev_info *)shost->hostdata;
	devinfo->intf = intf;
	devinfo->udev = udev;
	devinfo->resetting = 0;
	devinfo->shutdown = 0;
	devinfo->flags = dev_flags;
	init_usb_anchor(&devinfo->cmd_urbs);
	init_usb_anchor(&devinfo->sense_urbs);
	init_usb_anchor(&devinfo->data_urbs);
	spin_lock_init(&devinfo->lock);
	INIT_WORK(&devinfo->work, uas_do_work);
	INIT_WORK(&devinfo->scan_work, uas_scan_work);

	result = uas_configure_endpoints(devinfo);
	if (result)
		goto set_alt0;

	/*
	 * 1 tag is reserved for untagged commands +
	 * 1 tag to avoid off by one errors in some bridge firmwares
	 */
	shost->can_queue = devinfo->qdepth - 2;

	usb_set_intfdata(intf, shost);
	result = scsi_add_host(shost, &intf->dev);
	if (result)
		goto free_streams;

	/* Submit the delayed_work for SCSI-device scanning */
	schedule_work(&devinfo->scan_work);

	return result;

free_streams:
	uas_free_streams(devinfo);
	usb_set_intfdata(intf, NULL);
set_alt0:
	usb_set_interface(udev, intf->altsetting[0].desc.bInterfaceNumber, 0);
	if (shost)
		scsi_host_put(shost);
	return result;
}

static int uas_cmnd_list_empty(struct uas_dev_info *devinfo)
{
	unsigned long flags;
	int i, r = 1;

	spin_lock_irqsave(&devinfo->lock, flags);

	for (i = 0; i < devinfo->qdepth; i++) {
		if (devinfo->cmnd[i]) {
			r = 0; /* Not empty */
			break;
		}
	}

	spin_unlock_irqrestore(&devinfo->lock, flags);

	return r;
}

/*
 * Wait for any pending cmnds to complete, on usb-2 sense_urbs may temporarily
 * get empty while there still is more work to do due to sense-urbs completing
 * with a READ/WRITE_READY iu code, so keep waiting until the list gets empty.
 */
static int uas_wait_for_pending_cmnds(struct uas_dev_info *devinfo)
{
	unsigned long start_time;
	int r;

	start_time = jiffies;
	do {
		flush_work(&devinfo->work);

		r = usb_wait_anchor_empty_timeout(&devinfo->sense_urbs, 5000);
		if (r == 0)
			return -ETIME;

		r = usb_wait_anchor_empty_timeout(&devinfo->data_urbs, 500);
		if (r == 0)
			return -ETIME;

		if (time_after(jiffies, start_time + 5 * HZ))
			return -ETIME;
	} while (!uas_cmnd_list_empty(devinfo));

	return 0;
}

static int uas_pre_reset(struct usb_interface *intf)
{
	struct Scsi_Host *shost = usb_get_intfdata(intf);
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
	unsigned long flags;

	if (devinfo->shutdown)
		return 0;

	/* Block new requests */
	spin_lock_irqsave(shost->host_lock, flags);
	scsi_block_requests(shost);
	spin_unlock_irqrestore(shost->host_lock, flags);

	if (uas_wait_for_pending_cmnds(devinfo) != 0) {
		shost_printk(KERN_ERR, shost, "%s: timed out\n", __func__);
		scsi_unblock_requests(shost);
		return 1;
	}

	uas_free_streams(devinfo);

	return 0;
}

static int uas_post_reset(struct usb_interface *intf)
{
	struct Scsi_Host *shost = usb_get_intfdata(intf);
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
	unsigned long flags;
	int err;

	if (devinfo->shutdown)
		return 0;

	err = uas_configure_endpoints(devinfo);
	if (err && err != -ENODEV)
		shost_printk(KERN_ERR, shost,
			     "%s: alloc streams error %d after reset",
			     __func__, err);

	/* we must unblock the host in every case lest we deadlock */
	spin_lock_irqsave(shost->host_lock, flags);
	scsi_report_bus_reset(shost, 0);
	spin_unlock_irqrestore(shost->host_lock, flags);

	scsi_unblock_requests(shost);

	return err ? 1 : 0;
}

static int uas_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct Scsi_Host *shost = usb_get_intfdata(intf);
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;

	if (uas_wait_for_pending_cmnds(devinfo) != 0) {
		shost_printk(KERN_ERR, shost, "%s: timed out\n", __func__);
		return -ETIME;
	}

	return 0;
}

static int uas_resume(struct usb_interface *intf)
{
	return 0;
}

static int uas_reset_resume(struct usb_interface *intf)
{
	struct Scsi_Host *shost = usb_get_intfdata(intf);
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
	unsigned long flags;
	int err;

	err = uas_configure_endpoints(devinfo);
	if (err) {
		shost_printk(KERN_ERR, shost,
			     "%s: alloc streams error %d after reset",
			     __func__, err);
		return -EIO;
	}

	spin_lock_irqsave(shost->host_lock, flags);
	scsi_report_bus_reset(shost, 0);
	spin_unlock_irqrestore(shost->host_lock, flags);

	return 0;
}

static void uas_disconnect(struct usb_interface *intf)
{
	struct Scsi_Host *shost = usb_get_intfdata(intf);
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
	unsigned long flags;

	spin_lock_irqsave(&devinfo->lock, flags);
	devinfo->resetting = 1;
	spin_unlock_irqrestore(&devinfo->lock, flags);

	cancel_work_sync(&devinfo->work);
	usb_kill_anchored_urbs(&devinfo->cmd_urbs);
	usb_kill_anchored_urbs(&devinfo->sense_urbs);
	usb_kill_anchored_urbs(&devinfo->data_urbs);
	uas_zap_pending(devinfo, DID_NO_CONNECT);

	/*
	 * Prevent SCSI scanning (if it hasn't started yet)
	 * or wait for the SCSI-scanning routine to stop.
	 */
	cancel_work_sync(&devinfo->scan_work);

	scsi_remove_host(shost);
	uas_free_streams(devinfo);
	scsi_host_put(shost);
}

/*
 * Put the device back in usb-storage mode on shutdown, as some BIOS-es
 * hang on reboot when the device is still in uas mode. Note the reset is
 * necessary as some devices won't revert to usb-storage mode without it.
 */
static void uas_shutdown(struct device *dev)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct usb_device *udev = interface_to_usbdev(intf);
	struct Scsi_Host *shost = usb_get_intfdata(intf);
	struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;

	if (system_state != SYSTEM_RESTART)
		return;

	devinfo->shutdown = 1;
	uas_free_streams(devinfo);
	usb_set_interface(udev, intf->altsetting[0].desc.bInterfaceNumber, 0);
	usb_reset_device(udev);
}

static struct usb_driver uas_driver = {
	.name = "uas",
	.probe = uas_probe,
	.disconnect = uas_disconnect,
	.pre_reset = uas_pre_reset,
	.post_reset = uas_post_reset,
	.suspend = uas_suspend,
	.resume = uas_resume,
	.reset_resume = uas_reset_resume,
	.drvwrap.driver.shutdown = uas_shutdown,
	.id_table = uas_usb_ids,
};

static int __init uas_init(void)
{
	int rv;

	workqueue = alloc_workqueue("uas", WQ_MEM_RECLAIM, 0);
	if (!workqueue)
		return -ENOMEM;

	rv = usb_register(&uas_driver);
	if (rv) {
		destroy_workqueue(workqueue);
		return -ENOMEM;
	}

	return 0;
}

static void __exit uas_exit(void)
{
	usb_deregister(&uas_driver);
	destroy_workqueue(workqueue);
}

module_init(uas_init);
module_exit(uas_exit);

MODULE_LICENSE("GPL");
MODULE_IMPORT_NS(USB_STORAGE);
MODULE_AUTHOR(
	"Hans de Goede <hdegoede@redhat.com>, Matthew Wilcox and Sarah Sharp");