Bootlin logo

Elixir Cross Referencer

   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
/*******************************************************************************
 * Filename:  target_core_pscsi.c
 *
 * This file contains the generic target mode <-> Linux SCSI subsystem plugin.
 *
 * (c) Copyright 2003-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/string.h>
#include <linux/parser.h>
#include <linux/timer.h>
#include <linux/blkdev.h>
#include <linux/blk_types.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/genhd.h>
#include <linux/cdrom.h>
#include <linux/ratelimit.h>
#include <linux/module.h>
#include <asm/unaligned.h>

#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>

#include <target/target_core_base.h>
#include <target/target_core_backend.h>

#include "target_core_alua.h"
#include "target_core_internal.h"
#include "target_core_pscsi.h"

#define ISPRINT(a)  ((a >= ' ') && (a <= '~'))

static inline struct pscsi_dev_virt *PSCSI_DEV(struct se_device *dev)
{
	return container_of(dev, struct pscsi_dev_virt, dev);
}

static sense_reason_t pscsi_execute_cmd(struct se_cmd *cmd);
static void pscsi_req_done(struct request *, int);

/*	pscsi_attach_hba():
 *
 * 	pscsi_get_sh() used scsi_host_lookup() to locate struct Scsi_Host.
 *	from the passed SCSI Host ID.
 */
static int pscsi_attach_hba(struct se_hba *hba, u32 host_id)
{
	struct pscsi_hba_virt *phv;

	phv = kzalloc(sizeof(struct pscsi_hba_virt), GFP_KERNEL);
	if (!phv) {
		pr_err("Unable to allocate struct pscsi_hba_virt\n");
		return -ENOMEM;
	}
	phv->phv_host_id = host_id;
	phv->phv_mode = PHV_VIRTUAL_HOST_ID;

	hba->hba_ptr = phv;

	pr_debug("CORE_HBA[%d] - TCM SCSI HBA Driver %s on"
		" Generic Target Core Stack %s\n", hba->hba_id,
		PSCSI_VERSION, TARGET_CORE_VERSION);
	pr_debug("CORE_HBA[%d] - Attached SCSI HBA to Generic\n",
	       hba->hba_id);

	return 0;
}

static void pscsi_detach_hba(struct se_hba *hba)
{
	struct pscsi_hba_virt *phv = hba->hba_ptr;
	struct Scsi_Host *scsi_host = phv->phv_lld_host;

	if (scsi_host) {
		scsi_host_put(scsi_host);

		pr_debug("CORE_HBA[%d] - Detached SCSI HBA: %s from"
			" Generic Target Core\n", hba->hba_id,
			(scsi_host->hostt->name) ? (scsi_host->hostt->name) :
			"Unknown");
	} else
		pr_debug("CORE_HBA[%d] - Detached Virtual SCSI HBA"
			" from Generic Target Core\n", hba->hba_id);

	kfree(phv);
	hba->hba_ptr = NULL;
}

static int pscsi_pmode_enable_hba(struct se_hba *hba, unsigned long mode_flag)
{
	struct pscsi_hba_virt *phv = hba->hba_ptr;
	struct Scsi_Host *sh = phv->phv_lld_host;
	/*
	 * Release the struct Scsi_Host
	 */
	if (!mode_flag) {
		if (!sh)
			return 0;

		phv->phv_lld_host = NULL;
		phv->phv_mode = PHV_VIRTUAL_HOST_ID;

		pr_debug("CORE_HBA[%d] - Disabled pSCSI HBA Passthrough"
			" %s\n", hba->hba_id, (sh->hostt->name) ?
			(sh->hostt->name) : "Unknown");

		scsi_host_put(sh);
		return 0;
	}
	/*
	 * Otherwise, locate struct Scsi_Host from the original passed
	 * pSCSI Host ID and enable for phba mode
	 */
	sh = scsi_host_lookup(phv->phv_host_id);
	if (!sh) {
		pr_err("pSCSI: Unable to locate SCSI Host for"
			" phv_host_id: %d\n", phv->phv_host_id);
		return -EINVAL;
	}

	phv->phv_lld_host = sh;
	phv->phv_mode = PHV_LLD_SCSI_HOST_NO;

	pr_debug("CORE_HBA[%d] - Enabled pSCSI HBA Passthrough %s\n",
		hba->hba_id, (sh->hostt->name) ? (sh->hostt->name) : "Unknown");

	return 1;
}

static void pscsi_tape_read_blocksize(struct se_device *dev,
		struct scsi_device *sdev)
{
	unsigned char cdb[MAX_COMMAND_SIZE], *buf;
	int ret;

	buf = kzalloc(12, GFP_KERNEL);
	if (!buf)
		return;

	memset(cdb, 0, MAX_COMMAND_SIZE);
	cdb[0] = MODE_SENSE;
	cdb[4] = 0x0c; /* 12 bytes */

	ret = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE, buf, 12, NULL,
			HZ, 1, NULL);
	if (ret)
		goto out_free;

	/*
	 * If MODE_SENSE still returns zero, set the default value to 1024.
	 */
	sdev->sector_size = (buf[9] << 16) | (buf[10] << 8) | (buf[11]);
	if (!sdev->sector_size)
		sdev->sector_size = 1024;
out_free:
	kfree(buf);
}

static void
pscsi_set_inquiry_info(struct scsi_device *sdev, struct t10_wwn *wwn)
{
	unsigned char *buf;

	if (sdev->inquiry_len < INQUIRY_LEN)
		return;

	buf = sdev->inquiry;
	if (!buf)
		return;
	/*
	 * Use sdev->inquiry from drivers/scsi/scsi_scan.c:scsi_alloc_sdev()
	 */
	memcpy(&wwn->vendor[0], &buf[8], sizeof(wwn->vendor));
	memcpy(&wwn->model[0], &buf[16], sizeof(wwn->model));
	memcpy(&wwn->revision[0], &buf[32], sizeof(wwn->revision));
}

static int
pscsi_get_inquiry_vpd_serial(struct scsi_device *sdev, struct t10_wwn *wwn)
{
	unsigned char cdb[MAX_COMMAND_SIZE], *buf;
	int ret;

	buf = kzalloc(INQUIRY_VPD_SERIAL_LEN, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	memset(cdb, 0, MAX_COMMAND_SIZE);
	cdb[0] = INQUIRY;
	cdb[1] = 0x01; /* Query VPD */
	cdb[2] = 0x80; /* Unit Serial Number */
	cdb[3] = (INQUIRY_VPD_SERIAL_LEN >> 8) & 0xff;
	cdb[4] = (INQUIRY_VPD_SERIAL_LEN & 0xff);

	ret = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE, buf,
			      INQUIRY_VPD_SERIAL_LEN, NULL, HZ, 1, NULL);
	if (ret)
		goto out_free;

	snprintf(&wwn->unit_serial[0], INQUIRY_VPD_SERIAL_LEN, "%s", &buf[4]);

	wwn->t10_dev->dev_flags |= DF_FIRMWARE_VPD_UNIT_SERIAL;

	kfree(buf);
	return 0;

out_free:
	kfree(buf);
	return -EPERM;
}

static void
pscsi_get_inquiry_vpd_device_ident(struct scsi_device *sdev,
		struct t10_wwn *wwn)
{
	unsigned char cdb[MAX_COMMAND_SIZE], *buf, *page_83;
	int ident_len, page_len, off = 4, ret;
	struct t10_vpd *vpd;

	buf = kzalloc(INQUIRY_VPD_SERIAL_LEN, GFP_KERNEL);
	if (!buf)
		return;

	memset(cdb, 0, MAX_COMMAND_SIZE);
	cdb[0] = INQUIRY;
	cdb[1] = 0x01; /* Query VPD */
	cdb[2] = 0x83; /* Device Identifier */
	cdb[3] = (INQUIRY_VPD_DEVICE_IDENTIFIER_LEN >> 8) & 0xff;
	cdb[4] = (INQUIRY_VPD_DEVICE_IDENTIFIER_LEN & 0xff);

	ret = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE, buf,
			      INQUIRY_VPD_DEVICE_IDENTIFIER_LEN,
			      NULL, HZ, 1, NULL);
	if (ret)
		goto out;

	page_len = (buf[2] << 8) | buf[3];
	while (page_len > 0) {
		/* Grab a pointer to the Identification descriptor */
		page_83 = &buf[off];
		ident_len = page_83[3];
		if (!ident_len) {
			pr_err("page_83[3]: identifier"
					" length zero!\n");
			break;
		}
		pr_debug("T10 VPD Identifier Length: %d\n", ident_len);

		vpd = kzalloc(sizeof(struct t10_vpd), GFP_KERNEL);
		if (!vpd) {
			pr_err("Unable to allocate memory for"
					" struct t10_vpd\n");
			goto out;
		}
		INIT_LIST_HEAD(&vpd->vpd_list);

		transport_set_vpd_proto_id(vpd, page_83);
		transport_set_vpd_assoc(vpd, page_83);

		if (transport_set_vpd_ident_type(vpd, page_83) < 0) {
			off += (ident_len + 4);
			page_len -= (ident_len + 4);
			kfree(vpd);
			continue;
		}
		if (transport_set_vpd_ident(vpd, page_83) < 0) {
			off += (ident_len + 4);
			page_len -= (ident_len + 4);
			kfree(vpd);
			continue;
		}

		list_add_tail(&vpd->vpd_list, &wwn->t10_vpd_list);
		off += (ident_len + 4);
		page_len -= (ident_len + 4);
	}

out:
	kfree(buf);
}

static int pscsi_add_device_to_list(struct se_device *dev,
		struct scsi_device *sd)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct request_queue *q = sd->request_queue;

	pdv->pdv_sd = sd;

	if (!sd->queue_depth) {
		sd->queue_depth = PSCSI_DEFAULT_QUEUEDEPTH;

		pr_err("Set broken SCSI Device %d:%d:%llu"
			" queue_depth to %d\n", sd->channel, sd->id,
				sd->lun, sd->queue_depth);
	}

	dev->dev_attrib.hw_block_size = sd->sector_size;
	dev->dev_attrib.hw_max_sectors =
		min_t(int, sd->host->max_sectors, queue_max_hw_sectors(q));
	dev->dev_attrib.hw_queue_depth = sd->queue_depth;

	/*
	 * Setup our standard INQUIRY info into se_dev->t10_wwn
	 */
	pscsi_set_inquiry_info(sd, &dev->t10_wwn);

	/*
	 * Locate VPD WWN Information used for various purposes within
	 * the Storage Engine.
	 */
	if (!pscsi_get_inquiry_vpd_serial(sd, &dev->t10_wwn)) {
		/*
		 * If VPD Unit Serial returned GOOD status, try
		 * VPD Device Identification page (0x83).
		 */
		pscsi_get_inquiry_vpd_device_ident(sd, &dev->t10_wwn);
	}

	/*
	 * For TYPE_TAPE, attempt to determine blocksize with MODE_SENSE.
	 */
	if (sd->type == TYPE_TAPE)
		pscsi_tape_read_blocksize(dev, sd);
	return 0;
}

static struct se_device *pscsi_alloc_device(struct se_hba *hba,
		const char *name)
{
	struct pscsi_dev_virt *pdv;

	pdv = kzalloc(sizeof(struct pscsi_dev_virt), GFP_KERNEL);
	if (!pdv) {
		pr_err("Unable to allocate memory for struct pscsi_dev_virt\n");
		return NULL;
	}

	pr_debug("PSCSI: Allocated pdv: %p for %s\n", pdv, name);
	return &pdv->dev;
}

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static int pscsi_create_type_disk(struct se_device *dev, struct scsi_device *sd)
	__releases(sh->host_lock)
{
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct Scsi_Host *sh = sd->host;
	struct block_device *bd;
	int ret;

	if (scsi_device_get(sd)) {
		pr_err("scsi_device_get() failed for %d:%d:%d:%llu\n",
			sh->host_no, sd->channel, sd->id, sd->lun);
		spin_unlock_irq(sh->host_lock);
		return -EIO;
	}
	spin_unlock_irq(sh->host_lock);
	/*
	 * Claim exclusive struct block_device access to struct scsi_device
	 * for TYPE_DISK using supplied udev_path
	 */
	bd = blkdev_get_by_path(dev->udev_path,
				FMODE_WRITE|FMODE_READ|FMODE_EXCL, pdv);
	if (IS_ERR(bd)) {
		pr_err("pSCSI: blkdev_get_by_path() failed\n");
		scsi_device_put(sd);
		return PTR_ERR(bd);
	}
	pdv->pdv_bd = bd;

	ret = pscsi_add_device_to_list(dev, sd);
	if (ret) {
		blkdev_put(pdv->pdv_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
		scsi_device_put(sd);
		return ret;
	}

	pr_debug("CORE_PSCSI[%d] - Added TYPE_DISK for %d:%d:%d:%llu\n",
		phv->phv_host_id, sh->host_no, sd->channel, sd->id, sd->lun);
	return 0;
}

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static int pscsi_create_type_rom(struct se_device *dev, struct scsi_device *sd)
	__releases(sh->host_lock)
{
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	struct Scsi_Host *sh = sd->host;
	int ret;

	if (scsi_device_get(sd)) {
		pr_err("scsi_device_get() failed for %d:%d:%d:%llu\n",
			sh->host_no, sd->channel, sd->id, sd->lun);
		spin_unlock_irq(sh->host_lock);
		return -EIO;
	}
	spin_unlock_irq(sh->host_lock);

	ret = pscsi_add_device_to_list(dev, sd);
	if (ret) {
		scsi_device_put(sd);
		return ret;
	}
	pr_debug("CORE_PSCSI[%d] - Added Type: %s for %d:%d:%d:%llu\n",
		phv->phv_host_id, scsi_device_type(sd->type), sh->host_no,
		sd->channel, sd->id, sd->lun);

	return 0;
}

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static int pscsi_create_type_other(struct se_device *dev,
		struct scsi_device *sd)
	__releases(sh->host_lock)
{
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	struct Scsi_Host *sh = sd->host;
	int ret;

	spin_unlock_irq(sh->host_lock);
	ret = pscsi_add_device_to_list(dev, sd);
	if (ret)
		return ret;

	pr_debug("CORE_PSCSI[%d] - Added Type: %s for %d:%d:%d:%llu\n",
		phv->phv_host_id, scsi_device_type(sd->type), sh->host_no,
		sd->channel, sd->id, sd->lun);
	return 0;
}

static int pscsi_configure_device(struct se_device *dev)
{
	struct se_hba *hba = dev->se_hba;
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct scsi_device *sd;
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	struct Scsi_Host *sh = phv->phv_lld_host;
	int legacy_mode_enable = 0;
	int ret;

	if (!(pdv->pdv_flags & PDF_HAS_CHANNEL_ID) ||
	    !(pdv->pdv_flags & PDF_HAS_TARGET_ID) ||
	    !(pdv->pdv_flags & PDF_HAS_LUN_ID)) {
		pr_err("Missing scsi_channel_id=, scsi_target_id= and"
			" scsi_lun_id= parameters\n");
		return -EINVAL;
	}

	/*
	 * If not running in PHV_LLD_SCSI_HOST_NO mode, locate the
	 * struct Scsi_Host we will need to bring the TCM/pSCSI object online
	 */
	if (!sh) {
		if (phv->phv_mode == PHV_LLD_SCSI_HOST_NO) {
			pr_err("pSCSI: Unable to locate struct"
				" Scsi_Host for PHV_LLD_SCSI_HOST_NO\n");
			return -ENODEV;
		}
		/*
		 * For the newer PHV_VIRTUAL_HOST_ID struct scsi_device
		 * reference, we enforce that udev_path has been set
		 */
		if (!(dev->dev_flags & DF_USING_UDEV_PATH)) {
			pr_err("pSCSI: udev_path attribute has not"
				" been set before ENABLE=1\n");
			return -EINVAL;
		}
		/*
		 * If no scsi_host_id= was passed for PHV_VIRTUAL_HOST_ID,
		 * use the original TCM hba ID to reference Linux/SCSI Host No
		 * and enable for PHV_LLD_SCSI_HOST_NO mode.
		 */
		if (!(pdv->pdv_flags & PDF_HAS_VIRT_HOST_ID)) {
			if (hba->dev_count) {
				pr_err("pSCSI: Unable to set hba_mode"
					" with active devices\n");
				return -EEXIST;
			}

			if (pscsi_pmode_enable_hba(hba, 1) != 1)
				return -ENODEV;

			legacy_mode_enable = 1;
			hba->hba_flags |= HBA_FLAGS_PSCSI_MODE;
			sh = phv->phv_lld_host;
		} else {
			sh = scsi_host_lookup(pdv->pdv_host_id);
			if (!sh) {
				pr_err("pSCSI: Unable to locate"
					" pdv_host_id: %d\n", pdv->pdv_host_id);
				return -EINVAL;
			}
			pdv->pdv_lld_host = sh;
		}
	} else {
		if (phv->phv_mode == PHV_VIRTUAL_HOST_ID) {
			pr_err("pSCSI: PHV_VIRTUAL_HOST_ID set while"
				" struct Scsi_Host exists\n");
			return -EEXIST;
		}
	}

	spin_lock_irq(sh->host_lock);
	list_for_each_entry(sd, &sh->__devices, siblings) {
		if ((pdv->pdv_channel_id != sd->channel) ||
		    (pdv->pdv_target_id != sd->id) ||
		    (pdv->pdv_lun_id != sd->lun))
			continue;
		/*
		 * Functions will release the held struct scsi_host->host_lock
		 * before calling calling pscsi_add_device_to_list() to register
		 * struct scsi_device with target_core_mod.
		 */
		switch (sd->type) {
		case TYPE_DISK:
			ret = pscsi_create_type_disk(dev, sd);
			break;
		case TYPE_ROM:
			ret = pscsi_create_type_rom(dev, sd);
			break;
		default:
			ret = pscsi_create_type_other(dev, sd);
			break;
		}

		if (ret) {
			if (phv->phv_mode == PHV_VIRTUAL_HOST_ID)
				scsi_host_put(sh);
			else if (legacy_mode_enable) {
				pscsi_pmode_enable_hba(hba, 0);
				hba->hba_flags &= ~HBA_FLAGS_PSCSI_MODE;
			}
			pdv->pdv_sd = NULL;
			return ret;
		}
		return 0;
	}
	spin_unlock_irq(sh->host_lock);

	pr_err("pSCSI: Unable to locate %d:%d:%d:%d\n", sh->host_no,
		pdv->pdv_channel_id,  pdv->pdv_target_id, pdv->pdv_lun_id);

	if (phv->phv_mode == PHV_VIRTUAL_HOST_ID)
		scsi_host_put(sh);
	else if (legacy_mode_enable) {
		pscsi_pmode_enable_hba(hba, 0);
		hba->hba_flags &= ~HBA_FLAGS_PSCSI_MODE;
	}

	return -ENODEV;
}

static void pscsi_dev_call_rcu(struct rcu_head *p)
{
	struct se_device *dev = container_of(p, struct se_device, rcu_head);
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);

	kfree(pdv);
}

static void pscsi_free_device(struct se_device *dev)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	struct scsi_device *sd = pdv->pdv_sd;

	if (sd) {
		/*
		 * Release exclusive pSCSI internal struct block_device claim for
		 * struct scsi_device with TYPE_DISK from pscsi_create_type_disk()
		 */
		if ((sd->type == TYPE_DISK) && pdv->pdv_bd) {
			blkdev_put(pdv->pdv_bd,
				   FMODE_WRITE|FMODE_READ|FMODE_EXCL);
			pdv->pdv_bd = NULL;
		}
		/*
		 * For HBA mode PHV_LLD_SCSI_HOST_NO, release the reference
		 * to struct Scsi_Host now.
		 */
		if ((phv->phv_mode == PHV_LLD_SCSI_HOST_NO) &&
		    (phv->phv_lld_host != NULL))
			scsi_host_put(phv->phv_lld_host);
		else if (pdv->pdv_lld_host)
			scsi_host_put(pdv->pdv_lld_host);

		if ((sd->type == TYPE_DISK) || (sd->type == TYPE_ROM))
			scsi_device_put(sd);

		pdv->pdv_sd = NULL;
	}
	call_rcu(&dev->rcu_head, pscsi_dev_call_rcu);
}

static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg,
				     unsigned char *sense_buffer)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(cmd->se_dev);
	struct scsi_device *sd = pdv->pdv_sd;
	int result;
	struct pscsi_plugin_task *pt = cmd->priv;
	unsigned char *cdb;
	/*
	 * Special case for REPORT_LUNs handling where pscsi_plugin_task has
	 * not been allocated because TCM is handling the emulation directly.
	 */
	if (!pt)
		return;

	cdb = &pt->pscsi_cdb[0];
	result = pt->pscsi_result;
	/*
	 * Hack to make sure that Write-Protect modepage is set if R/O mode is
	 * forced.
	 */
	if (!cmd->data_length)
		goto after_mode_sense;

	if (((cdb[0] == MODE_SENSE) || (cdb[0] == MODE_SENSE_10)) &&
	     (status_byte(result) << 1) == SAM_STAT_GOOD) {
		bool read_only = target_lun_is_rdonly(cmd);

		if (read_only) {
			unsigned char *buf;

			buf = transport_kmap_data_sg(cmd);
			if (!buf)
				; /* XXX: TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE */

			if (cdb[0] == MODE_SENSE_10) {
				if (!(buf[3] & 0x80))
					buf[3] |= 0x80;
			} else {
				if (!(buf[2] & 0x80))
					buf[2] |= 0x80;
			}

			transport_kunmap_data_sg(cmd);
		}
	}
after_mode_sense:

	if (sd->type != TYPE_TAPE || !cmd->data_length)
		goto after_mode_select;

	/*
	 * Hack to correctly obtain the initiator requested blocksize for
	 * TYPE_TAPE.  Since this value is dependent upon each tape media,
	 * struct scsi_device->sector_size will not contain the correct value
	 * by default, so we go ahead and set it so
	 * TRANSPORT(dev)->get_blockdev() returns the correct value to the
	 * storage engine.
	 */
	if (((cdb[0] == MODE_SELECT) || (cdb[0] == MODE_SELECT_10)) &&
	      (status_byte(result) << 1) == SAM_STAT_GOOD) {
		unsigned char *buf;
		u16 bdl;
		u32 blocksize;

		buf = sg_virt(&sg[0]);
		if (!buf) {
			pr_err("Unable to get buf for scatterlist\n");
			goto after_mode_select;
		}

		if (cdb[0] == MODE_SELECT)
			bdl = (buf[3]);
		else
			bdl = (buf[6] << 8) | (buf[7]);

		if (!bdl)
			goto after_mode_select;

		if (cdb[0] == MODE_SELECT)
			blocksize = (buf[9] << 16) | (buf[10] << 8) |
					(buf[11]);
		else
			blocksize = (buf[13] << 16) | (buf[14] << 8) |
					(buf[15]);

		sd->sector_size = blocksize;
	}
after_mode_select:

	if (sense_buffer && (status_byte(result) & CHECK_CONDITION)) {
		memcpy(sense_buffer, pt->pscsi_sense, TRANSPORT_SENSE_BUFFER);
		cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
	}
}

enum {
	Opt_scsi_host_id, Opt_scsi_channel_id, Opt_scsi_target_id,
	Opt_scsi_lun_id, Opt_err
};

static match_table_t tokens = {
	{Opt_scsi_host_id, "scsi_host_id=%d"},
	{Opt_scsi_channel_id, "scsi_channel_id=%d"},
	{Opt_scsi_target_id, "scsi_target_id=%d"},
	{Opt_scsi_lun_id, "scsi_lun_id=%d"},
	{Opt_err, NULL}
};

static ssize_t pscsi_set_configfs_dev_params(struct se_device *dev,
		const char *page, ssize_t count)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	char *orig, *ptr, *opts;
	substring_t args[MAX_OPT_ARGS];
	int ret = 0, arg, token;

	opts = kstrdup(page, GFP_KERNEL);
	if (!opts)
		return -ENOMEM;

	orig = opts;

	while ((ptr = strsep(&opts, ",\n")) != NULL) {
		if (!*ptr)
			continue;

		token = match_token(ptr, tokens, args);
		switch (token) {
		case Opt_scsi_host_id:
			if (phv->phv_mode == PHV_LLD_SCSI_HOST_NO) {
				pr_err("PSCSI[%d]: Unable to accept"
					" scsi_host_id while phv_mode =="
					" PHV_LLD_SCSI_HOST_NO\n",
					phv->phv_host_id);
				ret = -EINVAL;
				goto out;
			}
			ret = match_int(args, &arg);
			if (ret)
				goto out;
			pdv->pdv_host_id = arg;
			pr_debug("PSCSI[%d]: Referencing SCSI Host ID:"
				" %d\n", phv->phv_host_id, pdv->pdv_host_id);
			pdv->pdv_flags |= PDF_HAS_VIRT_HOST_ID;
			break;
		case Opt_scsi_channel_id:
			ret = match_int(args, &arg);
			if (ret)
				goto out;
			pdv->pdv_channel_id = arg;
			pr_debug("PSCSI[%d]: Referencing SCSI Channel"
				" ID: %d\n",  phv->phv_host_id,
				pdv->pdv_channel_id);
			pdv->pdv_flags |= PDF_HAS_CHANNEL_ID;
			break;
		case Opt_scsi_target_id:
			ret = match_int(args, &arg);
			if (ret)
				goto out;
			pdv->pdv_target_id = arg;
			pr_debug("PSCSI[%d]: Referencing SCSI Target"
				" ID: %d\n", phv->phv_host_id,
				pdv->pdv_target_id);
			pdv->pdv_flags |= PDF_HAS_TARGET_ID;
			break;
		case Opt_scsi_lun_id:
			ret = match_int(args, &arg);
			if (ret)
				goto out;
			pdv->pdv_lun_id = arg;
			pr_debug("PSCSI[%d]: Referencing SCSI LUN ID:"
				" %d\n", phv->phv_host_id, pdv->pdv_lun_id);
			pdv->pdv_flags |= PDF_HAS_LUN_ID;
			break;
		default:
			break;
		}
	}

out:
	kfree(orig);
	return (!ret) ? count : ret;
}

static ssize_t pscsi_show_configfs_dev_params(struct se_device *dev, char *b)
{
	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct scsi_device *sd = pdv->pdv_sd;
	unsigned char host_id[16];
	ssize_t bl;
	int i;

	if (phv->phv_mode == PHV_VIRTUAL_HOST_ID)
		snprintf(host_id, 16, "%d", pdv->pdv_host_id);
	else
		snprintf(host_id, 16, "PHBA Mode");

	bl = sprintf(b, "SCSI Device Bus Location:"
		" Channel ID: %d Target ID: %d LUN: %d Host ID: %s\n",
		pdv->pdv_channel_id, pdv->pdv_target_id, pdv->pdv_lun_id,
		host_id);

	if (sd) {
		bl += sprintf(b + bl, "        ");
		bl += sprintf(b + bl, "Vendor: ");
		for (i = 0; i < 8; i++) {
			if (ISPRINT(sd->vendor[i]))   /* printable character? */
				bl += sprintf(b + bl, "%c", sd->vendor[i]);
			else
				bl += sprintf(b + bl, " ");
		}
		bl += sprintf(b + bl, " Model: ");
		for (i = 0; i < 16; i++) {
			if (ISPRINT(sd->model[i]))   /* printable character ? */
				bl += sprintf(b + bl, "%c", sd->model[i]);
			else
				bl += sprintf(b + bl, " ");
		}
		bl += sprintf(b + bl, " Rev: ");
		for (i = 0; i < 4; i++) {
			if (ISPRINT(sd->rev[i]))   /* printable character ? */
				bl += sprintf(b + bl, "%c", sd->rev[i]);
			else
				bl += sprintf(b + bl, " ");
		}
		bl += sprintf(b + bl, "\n");
	}
	return bl;
}

static void pscsi_bi_endio(struct bio *bio)
{
	bio_put(bio);
}

static inline struct bio *pscsi_get_bio(int nr_vecs)
{
	struct bio *bio;
	/*
	 * Use bio_malloc() following the comment in for bio -> struct request
	 * in block/blk-core.c:blk_make_request()
	 */
	bio = bio_kmalloc(GFP_KERNEL, nr_vecs);
	if (!bio) {
		pr_err("PSCSI: bio_kmalloc() failed\n");
		return NULL;
	}
	bio->bi_end_io = pscsi_bi_endio;

	return bio;
}

static sense_reason_t
pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
		struct request *req)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(cmd->se_dev);
	struct bio *bio = NULL;
	struct page *page;
	struct scatterlist *sg;
	u32 data_len = cmd->data_length, i, len, bytes, off;
	int nr_pages = (cmd->data_length + sgl[0].offset +
			PAGE_SIZE - 1) >> PAGE_SHIFT;
	int nr_vecs = 0, rc;
	int rw = (cmd->data_direction == DMA_TO_DEVICE);

	BUG_ON(!cmd->data_length);

	pr_debug("PSCSI: nr_pages: %d\n", nr_pages);

	for_each_sg(sgl, sg, sgl_nents, i) {
		page = sg_page(sg);
		off = sg->offset;
		len = sg->length;

		pr_debug("PSCSI: i: %d page: %p len: %d off: %d\n", i,
			page, len, off);

		/*
		 * We only have one page of data in each sg element,
		 * we can not cross a page boundary.
		 */
		if (off + len > PAGE_SIZE)
			goto fail;

		if (len > 0 && data_len > 0) {
			bytes = min_t(unsigned int, len, PAGE_SIZE - off);
			bytes = min(bytes, data_len);

			if (!bio) {
				nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
				nr_pages -= nr_vecs;
				/*
				 * Calls bio_kmalloc() and sets bio->bi_end_io()
				 */
				bio = pscsi_get_bio(nr_vecs);
				if (!bio)
					goto fail;

				if (rw)
					bio_set_op_attrs(bio, REQ_OP_WRITE, 0);

				pr_debug("PSCSI: Allocated bio: %p,"
					" dir: %s nr_vecs: %d\n", bio,
					(rw) ? "rw" : "r", nr_vecs);
			}

			pr_debug("PSCSI: Calling bio_add_pc_page() i: %d"
				" bio: %p page: %p len: %d off: %d\n", i, bio,
				page, len, off);

			rc = bio_add_pc_page(pdv->pdv_sd->request_queue,
					bio, page, bytes, off);
			if (rc != bytes)
				goto fail;

			pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n",
				bio->bi_vcnt, nr_vecs);

			if (bio->bi_vcnt > nr_vecs) {
				pr_debug("PSCSI: Reached bio->bi_vcnt max:"
					" %d i: %d bio: %p, allocating another"
					" bio\n", bio->bi_vcnt, i, bio);

				rc = blk_rq_append_bio(req, bio);
				if (rc) {
					pr_err("pSCSI: failed to append bio\n");
					goto fail;
				}

				/*
				 * Clear the pointer so that another bio will
				 * be allocated with pscsi_get_bio() above.
				 */
				bio = NULL;
			}

			data_len -= bytes;
		}
	}

	if (bio) {
		rc = blk_rq_append_bio(req, bio);
		if (rc) {
			pr_err("pSCSI: failed to append bio\n");
			goto fail;
		}
	}

	return 0;
fail:
	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}

static sense_reason_t
pscsi_parse_cdb(struct se_cmd *cmd)
{
	if (cmd->se_cmd_flags & SCF_BIDI)
		return TCM_UNSUPPORTED_SCSI_OPCODE;

	return passthrough_parse_cdb(cmd, pscsi_execute_cmd);
}

static sense_reason_t
pscsi_execute_cmd(struct se_cmd *cmd)
{
	struct scatterlist *sgl = cmd->t_data_sg;
	u32 sgl_nents = cmd->t_data_nents;
	struct pscsi_dev_virt *pdv = PSCSI_DEV(cmd->se_dev);
	struct pscsi_plugin_task *pt;
	struct request *req;
	sense_reason_t ret;

	/*
	 * Dynamically alloc cdb space, since it may be larger than
	 * TCM_MAX_COMMAND_SIZE
	 */
	pt = kzalloc(sizeof(*pt) + scsi_command_size(cmd->t_task_cdb), GFP_KERNEL);
	if (!pt) {
		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
	}
	cmd->priv = pt;

	memcpy(pt->pscsi_cdb, cmd->t_task_cdb,
		scsi_command_size(cmd->t_task_cdb));

	req = blk_get_request(pdv->pdv_sd->request_queue,
			(cmd->data_direction == DMA_TO_DEVICE),
			GFP_KERNEL);
	if (IS_ERR(req)) {
		pr_err("PSCSI: blk_get_request() failed\n");
		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
		goto fail;
	}

	blk_rq_set_block_pc(req);

	if (sgl) {
		ret = pscsi_map_sg(cmd, sgl, sgl_nents, req);
		if (ret)
			goto fail_put_request;
	}

	req->end_io = pscsi_req_done;
	req->end_io_data = cmd;
	req->cmd_len = scsi_command_size(pt->pscsi_cdb);
	req->cmd = &pt->pscsi_cdb[0];
	req->sense = &pt->pscsi_sense[0];
	req->sense_len = 0;
	if (pdv->pdv_sd->type == TYPE_DISK)
		req->timeout = PS_TIMEOUT_DISK;
	else
		req->timeout = PS_TIMEOUT_OTHER;
	req->retries = PS_RETRY;

	blk_execute_rq_nowait(pdv->pdv_sd->request_queue, NULL, req,
			(cmd->sam_task_attr == TCM_HEAD_TAG),
			pscsi_req_done);

	return 0;

fail_put_request:
	blk_put_request(req);
fail:
	kfree(pt);
	return ret;
}

/*	pscsi_get_device_type():
 *
 *
 */
static u32 pscsi_get_device_type(struct se_device *dev)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
	struct scsi_device *sd = pdv->pdv_sd;

	return (sd) ? sd->type : TYPE_NO_LUN;
}

static sector_t pscsi_get_blocks(struct se_device *dev)
{
	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);

	if (pdv->pdv_bd && pdv->pdv_bd->bd_part)
		return pdv->pdv_bd->bd_part->nr_sects;

	dump_stack();
	return 0;
}

static void pscsi_req_done(struct request *req, int uptodate)
{
	struct se_cmd *cmd = req->end_io_data;
	struct pscsi_plugin_task *pt = cmd->priv;

	pt->pscsi_result = req->errors;
	pt->pscsi_resid = req->resid_len;

	cmd->scsi_status = status_byte(pt->pscsi_result) << 1;
	if (cmd->scsi_status) {
		pr_debug("PSCSI Status Byte exception at cmd: %p CDB:"
			" 0x%02x Result: 0x%08x\n", cmd, pt->pscsi_cdb[0],
			pt->pscsi_result);
	}

	switch (host_byte(pt->pscsi_result)) {
	case DID_OK:
		target_complete_cmd(cmd, cmd->scsi_status);
		break;
	default:
		pr_debug("PSCSI Host Byte exception at cmd: %p CDB:"
			" 0x%02x Result: 0x%08x\n", cmd, pt->pscsi_cdb[0],
			pt->pscsi_result);
		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
		break;
	}

	__blk_put_request(req->q, req);
	kfree(pt);
}

static const struct target_backend_ops pscsi_ops = {
	.name			= "pscsi",
	.owner			= THIS_MODULE,
	.transport_flags	= TRANSPORT_FLAG_PASSTHROUGH,
	.attach_hba		= pscsi_attach_hba,
	.detach_hba		= pscsi_detach_hba,
	.pmode_enable_hba	= pscsi_pmode_enable_hba,
	.alloc_device		= pscsi_alloc_device,
	.configure_device	= pscsi_configure_device,
	.free_device		= pscsi_free_device,
	.transport_complete	= pscsi_transport_complete,
	.parse_cdb		= pscsi_parse_cdb,
	.set_configfs_dev_params = pscsi_set_configfs_dev_params,
	.show_configfs_dev_params = pscsi_show_configfs_dev_params,
	.get_device_type	= pscsi_get_device_type,
	.get_blocks		= pscsi_get_blocks,
	.tb_dev_attrib_attrs	= passthrough_attrib_attrs,
};

static int __init pscsi_module_init(void)
{
	return transport_backend_register(&pscsi_ops);
}

static void __exit pscsi_module_exit(void)
{
	target_backend_unregister(&pscsi_ops);
}

MODULE_DESCRIPTION("TCM PSCSI subsystem plugin");
MODULE_AUTHOR("nab@Linux-iSCSI.org");
MODULE_LICENSE("GPL");

module_init(pscsi_module_init);
module_exit(pscsi_module_exit);