Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

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
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
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
/*
 * Copyright (c) 2016 Avago Technologies.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful.
 * ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED, EXCEPT TO
 * THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID.
 * See the GNU General Public License for more details, a copy of which
 * can be found in the file COPYING included with this package
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/blk-mq.h>
#include <linux/parser.h>
#include <linux/random.h>
#include <uapi/scsi/fc/fc_fs.h>
#include <uapi/scsi/fc/fc_els.h>

#include "nvmet.h"
#include <linux/nvme-fc-driver.h>
#include <linux/nvme-fc.h>


/* *************************** Data Structures/Defines ****************** */


#define NVMET_LS_CTX_COUNT		4

/* for this implementation, assume small single frame rqst/rsp */
#define NVME_FC_MAX_LS_BUFFER_SIZE		2048

struct nvmet_fc_tgtport;
struct nvmet_fc_tgt_assoc;

struct nvmet_fc_ls_iod {
	struct nvmefc_tgt_ls_req	*lsreq;
	struct nvmefc_tgt_fcp_req	*fcpreq;	/* only if RS */

	struct list_head		ls_list;	/* tgtport->ls_list */

	struct nvmet_fc_tgtport		*tgtport;
	struct nvmet_fc_tgt_assoc	*assoc;

	u8				*rqstbuf;
	u8				*rspbuf;
	u16				rqstdatalen;
	dma_addr_t			rspdma;

	struct scatterlist		sg[2];

	struct work_struct		work;
} __aligned(sizeof(unsigned long long));

#define NVMET_FC_MAX_KB_PER_XFR		256

enum nvmet_fcp_datadir {
	NVMET_FCP_NODATA,
	NVMET_FCP_WRITE,
	NVMET_FCP_READ,
	NVMET_FCP_ABORTED,
};

struct nvmet_fc_fcp_iod {
	struct nvmefc_tgt_fcp_req	*fcpreq;

	struct nvme_fc_cmd_iu		cmdiubuf;
	struct nvme_fc_ersp_iu		rspiubuf;
	dma_addr_t			rspdma;
	struct scatterlist		*data_sg;
	struct scatterlist		*next_sg;
	int				data_sg_cnt;
	u32				next_sg_offset;
	u32				total_length;
	u32				offset;
	enum nvmet_fcp_datadir		io_dir;
	bool				active;
	bool				abort;
	spinlock_t			flock;

	struct nvmet_req		req;
	struct work_struct		work;

	struct nvmet_fc_tgtport		*tgtport;
	struct nvmet_fc_tgt_queue	*queue;

	struct list_head		fcp_list;	/* tgtport->fcp_list */
};

struct nvmet_fc_tgtport {

	struct nvmet_fc_target_port	fc_target_port;

	struct list_head		tgt_list; /* nvmet_fc_target_list */
	struct device			*dev;	/* dev for dma mapping */
	struct nvmet_fc_target_template	*ops;

	struct nvmet_fc_ls_iod		*iod;
	spinlock_t			lock;
	struct list_head		ls_list;
	struct list_head		ls_busylist;
	struct list_head		assoc_list;
	struct ida			assoc_cnt;
	struct nvmet_port		*port;
	struct kref			ref;
};

struct nvmet_fc_tgt_queue {
	bool				ninetypercent;
	u16				qid;
	u16				sqsize;
	u16				ersp_ratio;
	u16				sqhd;
	int				cpu;
	atomic_t			connected;
	atomic_t			sqtail;
	atomic_t			zrspcnt;
	atomic_t			rsn;
	spinlock_t			qlock;
	struct nvmet_port		*port;
	struct nvmet_cq			nvme_cq;
	struct nvmet_sq			nvme_sq;
	struct nvmet_fc_tgt_assoc	*assoc;
	struct nvmet_fc_fcp_iod		*fod;		/* array of fcp_iods */
	struct list_head		fod_list;
	struct workqueue_struct		*work_q;
	struct kref			ref;
} __aligned(sizeof(unsigned long long));

struct nvmet_fc_tgt_assoc {
	u64				association_id;
	u32				a_id;
	struct nvmet_fc_tgtport		*tgtport;
	struct list_head		a_list;
	struct nvmet_fc_tgt_queue	*queues[NVMET_NR_QUEUES];
	struct kref			ref;
};


static inline int
nvmet_fc_iodnum(struct nvmet_fc_ls_iod *iodptr)
{
	return (iodptr - iodptr->tgtport->iod);
}

static inline int
nvmet_fc_fodnum(struct nvmet_fc_fcp_iod *fodptr)
{
	return (fodptr - fodptr->queue->fod);
}


/*
 * Association and Connection IDs:
 *
 * Association ID will have random number in upper 6 bytes and zero
 *   in lower 2 bytes
 *
 * Connection IDs will be Association ID with QID or'd in lower 2 bytes
 *
 * note: Association ID = Connection ID for queue 0
 */
#define BYTES_FOR_QID			sizeof(u16)
#define BYTES_FOR_QID_SHIFT		(BYTES_FOR_QID * 8)
#define NVMET_FC_QUEUEID_MASK		((u64)((1 << BYTES_FOR_QID_SHIFT) - 1))

static inline u64
nvmet_fc_makeconnid(struct nvmet_fc_tgt_assoc *assoc, u16 qid)
{
	return (assoc->association_id | qid);
}

static inline u64
nvmet_fc_getassociationid(u64 connectionid)
{
	return connectionid & ~NVMET_FC_QUEUEID_MASK;
}

static inline u16
nvmet_fc_getqueueid(u64 connectionid)
{
	return (u16)(connectionid & NVMET_FC_QUEUEID_MASK);
}

static inline struct nvmet_fc_tgtport *
targetport_to_tgtport(struct nvmet_fc_target_port *targetport)
{
	return container_of(targetport, struct nvmet_fc_tgtport,
				 fc_target_port);
}

static inline struct nvmet_fc_fcp_iod *
nvmet_req_to_fod(struct nvmet_req *nvme_req)
{
	return container_of(nvme_req, struct nvmet_fc_fcp_iod, req);
}


/* *************************** Globals **************************** */


static DEFINE_SPINLOCK(nvmet_fc_tgtlock);

static LIST_HEAD(nvmet_fc_target_list);
static DEFINE_IDA(nvmet_fc_tgtport_cnt);


static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
static void nvmet_fc_handle_fcp_rqst_work(struct work_struct *work);
static void nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc);
static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
static int nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue);
static void nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport);
static int nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport);


/* *********************** FC-NVME DMA Handling **************************** */

/*
 * The fcloop device passes in a NULL device pointer. Real LLD's will
 * pass in a valid device pointer. If NULL is passed to the dma mapping
 * routines, depending on the platform, it may or may not succeed, and
 * may crash.
 *
 * As such:
 * Wrapper all the dma routines and check the dev pointer.
 *
 * If simple mappings (return just a dma address, we'll noop them,
 * returning a dma address of 0.
 *
 * On more complex mappings (dma_map_sg), a pseudo routine fills
 * in the scatter list, setting all dma addresses to 0.
 */

static inline dma_addr_t
fc_dma_map_single(struct device *dev, void *ptr, size_t size,
		enum dma_data_direction dir)
{
	return dev ? dma_map_single(dev, ptr, size, dir) : (dma_addr_t)0L;
}

static inline int
fc_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
	return dev ? dma_mapping_error(dev, dma_addr) : 0;
}

static inline void
fc_dma_unmap_single(struct device *dev, dma_addr_t addr, size_t size,
	enum dma_data_direction dir)
{
	if (dev)
		dma_unmap_single(dev, addr, size, dir);
}

static inline void
fc_dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
		enum dma_data_direction dir)
{
	if (dev)
		dma_sync_single_for_cpu(dev, addr, size, dir);
}

static inline void
fc_dma_sync_single_for_device(struct device *dev, dma_addr_t addr, size_t size,
		enum dma_data_direction dir)
{
	if (dev)
		dma_sync_single_for_device(dev, addr, size, dir);
}

/* pseudo dma_map_sg call */
static int
fc_map_sg(struct scatterlist *sg, int nents)
{
	struct scatterlist *s;
	int i;

	WARN_ON(nents == 0 || sg[0].length == 0);

	for_each_sg(sg, s, nents, i) {
		s->dma_address = 0L;
#ifdef CONFIG_NEED_SG_DMA_LENGTH
		s->dma_length = s->length;
#endif
	}
	return nents;
}

static inline int
fc_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
		enum dma_data_direction dir)
{
	return dev ? dma_map_sg(dev, sg, nents, dir) : fc_map_sg(sg, nents);
}

static inline void
fc_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
		enum dma_data_direction dir)
{
	if (dev)
		dma_unmap_sg(dev, sg, nents, dir);
}


/* *********************** FC-NVME Port Management ************************ */


static int
nvmet_fc_alloc_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
{
	struct nvmet_fc_ls_iod *iod;
	int i;

	iod = kcalloc(NVMET_LS_CTX_COUNT, sizeof(struct nvmet_fc_ls_iod),
			GFP_KERNEL);
	if (!iod)
		return -ENOMEM;

	tgtport->iod = iod;

	for (i = 0; i < NVMET_LS_CTX_COUNT; iod++, i++) {
		INIT_WORK(&iod->work, nvmet_fc_handle_ls_rqst_work);
		iod->tgtport = tgtport;
		list_add_tail(&iod->ls_list, &tgtport->ls_list);

		iod->rqstbuf = kcalloc(2, NVME_FC_MAX_LS_BUFFER_SIZE,
			GFP_KERNEL);
		if (!iod->rqstbuf)
			goto out_fail;

		iod->rspbuf = iod->rqstbuf + NVME_FC_MAX_LS_BUFFER_SIZE;

		iod->rspdma = fc_dma_map_single(tgtport->dev, iod->rspbuf,
						NVME_FC_MAX_LS_BUFFER_SIZE,
						DMA_TO_DEVICE);
		if (fc_dma_mapping_error(tgtport->dev, iod->rspdma))
			goto out_fail;
	}

	return 0;

out_fail:
	kfree(iod->rqstbuf);
	list_del(&iod->ls_list);
	for (iod--, i--; i >= 0; iod--, i--) {
		fc_dma_unmap_single(tgtport->dev, iod->rspdma,
				NVME_FC_MAX_LS_BUFFER_SIZE, DMA_TO_DEVICE);
		kfree(iod->rqstbuf);
		list_del(&iod->ls_list);
	}

	kfree(iod);

	return -EFAULT;
}

static void
nvmet_fc_free_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
{
	struct nvmet_fc_ls_iod *iod = tgtport->iod;
	int i;

	for (i = 0; i < NVMET_LS_CTX_COUNT; iod++, i++) {
		fc_dma_unmap_single(tgtport->dev,
				iod->rspdma, NVME_FC_MAX_LS_BUFFER_SIZE,
				DMA_TO_DEVICE);
		kfree(iod->rqstbuf);
		list_del(&iod->ls_list);
	}
	kfree(tgtport->iod);
}

static struct nvmet_fc_ls_iod *
nvmet_fc_alloc_ls_iod(struct nvmet_fc_tgtport *tgtport)
{
	static struct nvmet_fc_ls_iod *iod;
	unsigned long flags;

	spin_lock_irqsave(&tgtport->lock, flags);
	iod = list_first_entry_or_null(&tgtport->ls_list,
					struct nvmet_fc_ls_iod, ls_list);
	if (iod)
		list_move_tail(&iod->ls_list, &tgtport->ls_busylist);
	spin_unlock_irqrestore(&tgtport->lock, flags);
	return iod;
}


static void
nvmet_fc_free_ls_iod(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_ls_iod *iod)
{
	unsigned long flags;

	spin_lock_irqsave(&tgtport->lock, flags);
	list_move(&iod->ls_list, &tgtport->ls_list);
	spin_unlock_irqrestore(&tgtport->lock, flags);
}

static void
nvmet_fc_prep_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
				struct nvmet_fc_tgt_queue *queue)
{
	struct nvmet_fc_fcp_iod *fod = queue->fod;
	int i;

	for (i = 0; i < queue->sqsize; fod++, i++) {
		INIT_WORK(&fod->work, nvmet_fc_handle_fcp_rqst_work);
		fod->tgtport = tgtport;
		fod->queue = queue;
		fod->active = false;
		list_add_tail(&fod->fcp_list, &queue->fod_list);
		spin_lock_init(&fod->flock);

		fod->rspdma = fc_dma_map_single(tgtport->dev, &fod->rspiubuf,
					sizeof(fod->rspiubuf), DMA_TO_DEVICE);
		if (fc_dma_mapping_error(tgtport->dev, fod->rspdma)) {
			list_del(&fod->fcp_list);
			for (fod--, i--; i >= 0; fod--, i--) {
				fc_dma_unmap_single(tgtport->dev, fod->rspdma,
						sizeof(fod->rspiubuf),
						DMA_TO_DEVICE);
				fod->rspdma = 0L;
				list_del(&fod->fcp_list);
			}

			return;
		}
	}
}

static void
nvmet_fc_destroy_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
				struct nvmet_fc_tgt_queue *queue)
{
	struct nvmet_fc_fcp_iod *fod = queue->fod;
	int i;

	for (i = 0; i < queue->sqsize; fod++, i++) {
		if (fod->rspdma)
			fc_dma_unmap_single(tgtport->dev, fod->rspdma,
				sizeof(fod->rspiubuf), DMA_TO_DEVICE);
	}
}

static struct nvmet_fc_fcp_iod *
nvmet_fc_alloc_fcp_iod(struct nvmet_fc_tgt_queue *queue)
{
	static struct nvmet_fc_fcp_iod *fod;
	unsigned long flags;

	spin_lock_irqsave(&queue->qlock, flags);
	fod = list_first_entry_or_null(&queue->fod_list,
					struct nvmet_fc_fcp_iod, fcp_list);
	if (fod) {
		list_del(&fod->fcp_list);
		fod->active = true;
		fod->abort = false;
		/*
		 * no queue reference is taken, as it was taken by the
		 * queue lookup just prior to the allocation. The iod
		 * will "inherit" that reference.
		 */
	}
	spin_unlock_irqrestore(&queue->qlock, flags);
	return fod;
}


static void
nvmet_fc_free_fcp_iod(struct nvmet_fc_tgt_queue *queue,
			struct nvmet_fc_fcp_iod *fod)
{
	unsigned long flags;

	spin_lock_irqsave(&queue->qlock, flags);
	list_add_tail(&fod->fcp_list, &fod->queue->fod_list);
	fod->active = false;
	spin_unlock_irqrestore(&queue->qlock, flags);

	/*
	 * release the reference taken at queue lookup and fod allocation
	 */
	nvmet_fc_tgt_q_put(queue);
}

static int
nvmet_fc_queue_to_cpu(struct nvmet_fc_tgtport *tgtport, int qid)
{
	int cpu, idx, cnt;

	if (!(tgtport->ops->target_features &
			NVMET_FCTGTFEAT_NEEDS_CMD_CPUSCHED) ||
	    tgtport->ops->max_hw_queues == 1)
		return WORK_CPU_UNBOUND;

	/* Simple cpu selection based on qid modulo active cpu count */
	idx = !qid ? 0 : (qid - 1) % num_active_cpus();

	/* find the n'th active cpu */
	for (cpu = 0, cnt = 0; ; ) {
		if (cpu_active(cpu)) {
			if (cnt == idx)
				break;
			cnt++;
		}
		cpu = (cpu + 1) % num_possible_cpus();
	}

	return cpu;
}

static struct nvmet_fc_tgt_queue *
nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
			u16 qid, u16 sqsize)
{
	struct nvmet_fc_tgt_queue *queue;
	unsigned long flags;
	int ret;

	if (qid >= NVMET_NR_QUEUES)
		return NULL;

	queue = kzalloc((sizeof(*queue) +
				(sizeof(struct nvmet_fc_fcp_iod) * sqsize)),
				GFP_KERNEL);
	if (!queue)
		return NULL;

	if (!nvmet_fc_tgt_a_get(assoc))
		goto out_free_queue;

	queue->work_q = alloc_workqueue("ntfc%d.%d.%d", 0, 0,
				assoc->tgtport->fc_target_port.port_num,
				assoc->a_id, qid);
	if (!queue->work_q)
		goto out_a_put;

	queue->fod = (struct nvmet_fc_fcp_iod *)&queue[1];
	queue->qid = qid;
	queue->sqsize = sqsize;
	queue->assoc = assoc;
	queue->port = assoc->tgtport->port;
	queue->cpu = nvmet_fc_queue_to_cpu(assoc->tgtport, qid);
	INIT_LIST_HEAD(&queue->fod_list);
	atomic_set(&queue->connected, 0);
	atomic_set(&queue->sqtail, 0);
	atomic_set(&queue->rsn, 1);
	atomic_set(&queue->zrspcnt, 0);
	spin_lock_init(&queue->qlock);
	kref_init(&queue->ref);

	nvmet_fc_prep_fcp_iodlist(assoc->tgtport, queue);

	ret = nvmet_sq_init(&queue->nvme_sq);
	if (ret)
		goto out_fail_iodlist;

	WARN_ON(assoc->queues[qid]);
	spin_lock_irqsave(&assoc->tgtport->lock, flags);
	assoc->queues[qid] = queue;
	spin_unlock_irqrestore(&assoc->tgtport->lock, flags);

	return queue;

out_fail_iodlist:
	nvmet_fc_destroy_fcp_iodlist(assoc->tgtport, queue);
	destroy_workqueue(queue->work_q);
out_a_put:
	nvmet_fc_tgt_a_put(assoc);
out_free_queue:
	kfree(queue);
	return NULL;
}


static void
nvmet_fc_tgt_queue_free(struct kref *ref)
{
	struct nvmet_fc_tgt_queue *queue =
		container_of(ref, struct nvmet_fc_tgt_queue, ref);
	unsigned long flags;

	spin_lock_irqsave(&queue->assoc->tgtport->lock, flags);
	queue->assoc->queues[queue->qid] = NULL;
	spin_unlock_irqrestore(&queue->assoc->tgtport->lock, flags);

	nvmet_fc_destroy_fcp_iodlist(queue->assoc->tgtport, queue);

	nvmet_fc_tgt_a_put(queue->assoc);

	destroy_workqueue(queue->work_q);

	kfree(queue);
}

static void
nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue)
{
	kref_put(&queue->ref, nvmet_fc_tgt_queue_free);
}

static int
nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue)
{
	return kref_get_unless_zero(&queue->ref);
}


static void
nvmet_fc_abort_op(struct nvmet_fc_tgtport *tgtport,
				struct nvmefc_tgt_fcp_req *fcpreq)
{
	int ret;

	fcpreq->op = NVMET_FCOP_ABORT;
	fcpreq->offset = 0;
	fcpreq->timeout = 0;
	fcpreq->transfer_length = 0;
	fcpreq->transferred_length = 0;
	fcpreq->fcp_error = 0;
	fcpreq->sg_cnt = 0;

	ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fcpreq);
	if (ret)
		/* should never reach here !! */
		WARN_ON(1);
}


static void
nvmet_fc_delete_target_queue(struct nvmet_fc_tgt_queue *queue)
{
	struct nvmet_fc_fcp_iod *fod = queue->fod;
	unsigned long flags;
	int i;
	bool disconnect;

	disconnect = atomic_xchg(&queue->connected, 0);

	spin_lock_irqsave(&queue->qlock, flags);
	/* about outstanding io's */
	for (i = 0; i < queue->sqsize; fod++, i++) {
		if (fod->active) {
			spin_lock(&fod->flock);
			fod->abort = true;
			spin_unlock(&fod->flock);
		}
	}
	spin_unlock_irqrestore(&queue->qlock, flags);

	flush_workqueue(queue->work_q);

	if (disconnect)
		nvmet_sq_destroy(&queue->nvme_sq);

	nvmet_fc_tgt_q_put(queue);
}

static struct nvmet_fc_tgt_queue *
nvmet_fc_find_target_queue(struct nvmet_fc_tgtport *tgtport,
				u64 connection_id)
{
	struct nvmet_fc_tgt_assoc *assoc;
	struct nvmet_fc_tgt_queue *queue;
	u64 association_id = nvmet_fc_getassociationid(connection_id);
	u16 qid = nvmet_fc_getqueueid(connection_id);
	unsigned long flags;

	spin_lock_irqsave(&tgtport->lock, flags);
	list_for_each_entry(assoc, &tgtport->assoc_list, a_list) {
		if (association_id == assoc->association_id) {
			queue = assoc->queues[qid];
			if (queue &&
			    (!atomic_read(&queue->connected) ||
			     !nvmet_fc_tgt_q_get(queue)))
				queue = NULL;
			spin_unlock_irqrestore(&tgtport->lock, flags);
			return queue;
		}
	}
	spin_unlock_irqrestore(&tgtport->lock, flags);
	return NULL;
}

static struct nvmet_fc_tgt_assoc *
nvmet_fc_alloc_target_assoc(struct nvmet_fc_tgtport *tgtport)
{
	struct nvmet_fc_tgt_assoc *assoc, *tmpassoc;
	unsigned long flags;
	u64 ran;
	int idx;
	bool needrandom = true;

	assoc = kzalloc(sizeof(*assoc), GFP_KERNEL);
	if (!assoc)
		return NULL;

	idx = ida_simple_get(&tgtport->assoc_cnt, 0, 0, GFP_KERNEL);
	if (idx < 0)
		goto out_free_assoc;

	if (!nvmet_fc_tgtport_get(tgtport))
		goto out_ida_put;

	assoc->tgtport = tgtport;
	assoc->a_id = idx;
	INIT_LIST_HEAD(&assoc->a_list);
	kref_init(&assoc->ref);

	while (needrandom) {
		get_random_bytes(&ran, sizeof(ran) - BYTES_FOR_QID);
		ran = ran << BYTES_FOR_QID_SHIFT;

		spin_lock_irqsave(&tgtport->lock, flags);
		needrandom = false;
		list_for_each_entry(tmpassoc, &tgtport->assoc_list, a_list)
			if (ran == tmpassoc->association_id) {
				needrandom = true;
				break;
			}
		if (!needrandom) {
			assoc->association_id = ran;
			list_add_tail(&assoc->a_list, &tgtport->assoc_list);
		}
		spin_unlock_irqrestore(&tgtport->lock, flags);
	}

	return assoc;

out_ida_put:
	ida_simple_remove(&tgtport->assoc_cnt, idx);
out_free_assoc:
	kfree(assoc);
	return NULL;
}

static void
nvmet_fc_target_assoc_free(struct kref *ref)
{
	struct nvmet_fc_tgt_assoc *assoc =
		container_of(ref, struct nvmet_fc_tgt_assoc, ref);
	struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
	unsigned long flags;

	spin_lock_irqsave(&tgtport->lock, flags);
	list_del(&assoc->a_list);
	spin_unlock_irqrestore(&tgtport->lock, flags);
	ida_simple_remove(&tgtport->assoc_cnt, assoc->a_id);
	kfree(assoc);
	nvmet_fc_tgtport_put(tgtport);
}

static void
nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc)
{
	kref_put(&assoc->ref, nvmet_fc_target_assoc_free);
}

static int
nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc)
{
	return kref_get_unless_zero(&assoc->ref);
}

static void
nvmet_fc_delete_target_assoc(struct nvmet_fc_tgt_assoc *assoc)
{
	struct nvmet_fc_tgtport *tgtport = assoc->tgtport;
	struct nvmet_fc_tgt_queue *queue;
	unsigned long flags;
	int i;

	spin_lock_irqsave(&tgtport->lock, flags);
	for (i = NVMET_NR_QUEUES - 1; i >= 0; i--) {
		queue = assoc->queues[i];
		if (queue) {
			if (!nvmet_fc_tgt_q_get(queue))
				continue;
			spin_unlock_irqrestore(&tgtport->lock, flags);
			nvmet_fc_delete_target_queue(queue);
			nvmet_fc_tgt_q_put(queue);
			spin_lock_irqsave(&tgtport->lock, flags);
		}
	}
	spin_unlock_irqrestore(&tgtport->lock, flags);

	nvmet_fc_tgt_a_put(assoc);
}

static struct nvmet_fc_tgt_assoc *
nvmet_fc_find_target_assoc(struct nvmet_fc_tgtport *tgtport,
				u64 association_id)
{
	struct nvmet_fc_tgt_assoc *assoc;
	struct nvmet_fc_tgt_assoc *ret = NULL;
	unsigned long flags;

	spin_lock_irqsave(&tgtport->lock, flags);
	list_for_each_entry(assoc, &tgtport->assoc_list, a_list) {
		if (association_id == assoc->association_id) {
			ret = assoc;
			nvmet_fc_tgt_a_get(assoc);
			break;
		}
	}
	spin_unlock_irqrestore(&tgtport->lock, flags);

	return ret;
}


/**
 * nvme_fc_register_targetport - transport entry point called by an
 *                              LLDD to register the existence of a local
 *                              NVME subystem FC port.
 * @pinfo:     pointer to information about the port to be registered
 * @template:  LLDD entrypoints and operational parameters for the port
 * @dev:       physical hardware device node port corresponds to. Will be
 *             used for DMA mappings
 * @portptr:   pointer to a local port pointer. Upon success, the routine
 *             will allocate a nvme_fc_local_port structure and place its
 *             address in the local port pointer. Upon failure, local port
 *             pointer will be set to NULL.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
			struct nvmet_fc_target_template *template,
			struct device *dev,
			struct nvmet_fc_target_port **portptr)
{
	struct nvmet_fc_tgtport *newrec;
	unsigned long flags;
	int ret, idx;

	if (!template->xmt_ls_rsp || !template->fcp_op ||
	    !template->targetport_delete ||
	    !template->max_hw_queues || !template->max_sgl_segments ||
	    !template->max_dif_sgl_segments || !template->dma_boundary) {
		ret = -EINVAL;
		goto out_regtgt_failed;
	}

	newrec = kzalloc((sizeof(*newrec) + template->target_priv_sz),
			 GFP_KERNEL);
	if (!newrec) {
		ret = -ENOMEM;
		goto out_regtgt_failed;
	}

	idx = ida_simple_get(&nvmet_fc_tgtport_cnt, 0, 0, GFP_KERNEL);
	if (idx < 0) {
		ret = -ENOSPC;
		goto out_fail_kfree;
	}

	if (!get_device(dev) && dev) {
		ret = -ENODEV;
		goto out_ida_put;
	}

	newrec->fc_target_port.node_name = pinfo->node_name;
	newrec->fc_target_port.port_name = pinfo->port_name;
	newrec->fc_target_port.private = &newrec[1];
	newrec->fc_target_port.port_id = pinfo->port_id;
	newrec->fc_target_port.port_num = idx;
	INIT_LIST_HEAD(&newrec->tgt_list);
	newrec->dev = dev;
	newrec->ops = template;
	spin_lock_init(&newrec->lock);
	INIT_LIST_HEAD(&newrec->ls_list);
	INIT_LIST_HEAD(&newrec->ls_busylist);
	INIT_LIST_HEAD(&newrec->assoc_list);
	kref_init(&newrec->ref);
	ida_init(&newrec->assoc_cnt);

	ret = nvmet_fc_alloc_ls_iodlist(newrec);
	if (ret) {
		ret = -ENOMEM;
		goto out_free_newrec;
	}

	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
	list_add_tail(&newrec->tgt_list, &nvmet_fc_target_list);
	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

	*portptr = &newrec->fc_target_port;
	return 0;

out_free_newrec:
	put_device(dev);
out_ida_put:
	ida_simple_remove(&nvmet_fc_tgtport_cnt, idx);
out_fail_kfree:
	kfree(newrec);
out_regtgt_failed:
	*portptr = NULL;
	return ret;
}
EXPORT_SYMBOL_GPL(nvmet_fc_register_targetport);


static void
nvmet_fc_free_tgtport(struct kref *ref)
{
	struct nvmet_fc_tgtport *tgtport =
		container_of(ref, struct nvmet_fc_tgtport, ref);
	struct device *dev = tgtport->dev;
	unsigned long flags;

	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
	list_del(&tgtport->tgt_list);
	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

	nvmet_fc_free_ls_iodlist(tgtport);

	/* let the LLDD know we've finished tearing it down */
	tgtport->ops->targetport_delete(&tgtport->fc_target_port);

	ida_simple_remove(&nvmet_fc_tgtport_cnt,
			tgtport->fc_target_port.port_num);

	ida_destroy(&tgtport->assoc_cnt);

	kfree(tgtport);

	put_device(dev);
}

static void
nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport)
{
	kref_put(&tgtport->ref, nvmet_fc_free_tgtport);
}

static int
nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport)
{
	return kref_get_unless_zero(&tgtport->ref);
}

static void
__nvmet_fc_free_assocs(struct nvmet_fc_tgtport *tgtport)
{
	struct nvmet_fc_tgt_assoc *assoc, *next;
	unsigned long flags;

	spin_lock_irqsave(&tgtport->lock, flags);
	list_for_each_entry_safe(assoc, next,
				&tgtport->assoc_list, a_list) {
		if (!nvmet_fc_tgt_a_get(assoc))
			continue;
		spin_unlock_irqrestore(&tgtport->lock, flags);
		nvmet_fc_delete_target_assoc(assoc);
		nvmet_fc_tgt_a_put(assoc);
		spin_lock_irqsave(&tgtport->lock, flags);
	}
	spin_unlock_irqrestore(&tgtport->lock, flags);
}

/*
 * nvmet layer has called to terminate an association
 */
static void
nvmet_fc_delete_ctrl(struct nvmet_ctrl *ctrl)
{
	struct nvmet_fc_tgtport *tgtport, *next;
	struct nvmet_fc_tgt_assoc *assoc;
	struct nvmet_fc_tgt_queue *queue;
	unsigned long flags;
	bool found_ctrl = false;

	/* this is a bit ugly, but don't want to make locks layered */
	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
	list_for_each_entry_safe(tgtport, next, &nvmet_fc_target_list,
			tgt_list) {
		if (!nvmet_fc_tgtport_get(tgtport))
			continue;
		spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);

		spin_lock_irqsave(&tgtport->lock, flags);
		list_for_each_entry(assoc, &tgtport->assoc_list, a_list) {
			queue = assoc->queues[0];
			if (queue && queue->nvme_sq.ctrl == ctrl) {
				if (nvmet_fc_tgt_a_get(assoc))
					found_ctrl = true;
				break;
			}
		}
		spin_unlock_irqrestore(&tgtport->lock, flags);

		nvmet_fc_tgtport_put(tgtport);

		if (found_ctrl) {
			nvmet_fc_delete_target_assoc(assoc);
			nvmet_fc_tgt_a_put(assoc);
			return;
		}

		spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
	}
	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
}

/**
 * nvme_fc_unregister_targetport - transport entry point called by an
 *                              LLDD to deregister/remove a previously
 *                              registered a local NVME subsystem FC port.
 * @tgtport: pointer to the (registered) target port that is to be
 *           deregistered.
 *
 * Returns:
 * a completion status. Must be 0 upon success; a negative errno
 * (ex: -ENXIO) upon failure.
 */
int
nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *target_port)
{
	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);

	/* terminate any outstanding associations */
	__nvmet_fc_free_assocs(tgtport);

	nvmet_fc_tgtport_put(tgtport);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmet_fc_unregister_targetport);


/* *********************** FC-NVME LS Handling **************************** */


static void
nvmet_fc_format_rsp_hdr(void *buf, u8 ls_cmd, u32 desc_len, u8 rqst_ls_cmd)
{
	struct fcnvme_ls_acc_hdr *acc = buf;

	acc->w0.ls_cmd = ls_cmd;
	acc->desc_list_len = desc_len;
	acc->rqst.desc_tag = cpu_to_be32(FCNVME_LSDESC_RQST);
	acc->rqst.desc_len =
			fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_rqst));
	acc->rqst.w0.ls_cmd = rqst_ls_cmd;
}

static int
nvmet_fc_format_rjt(void *buf, u16 buflen, u8 ls_cmd,
			u8 reason, u8 explanation, u8 vendor)
{
	struct fcnvme_ls_rjt *rjt = buf;

	nvmet_fc_format_rsp_hdr(buf, FCNVME_LSDESC_RQST,
			fcnvme_lsdesc_len(sizeof(struct fcnvme_ls_rjt)),
			ls_cmd);
	rjt->rjt.desc_tag = cpu_to_be32(FCNVME_LSDESC_RJT);
	rjt->rjt.desc_len = fcnvme_lsdesc_len(sizeof(struct fcnvme_lsdesc_rjt));
	rjt->rjt.reason_code = reason;
	rjt->rjt.reason_explanation = explanation;
	rjt->rjt.vendor = vendor;

	return sizeof(struct fcnvme_ls_rjt);
}

/* Validation Error indexes into the string table below */
enum {
	VERR_NO_ERROR		= 0,
	VERR_CR_ASSOC_LEN	= 1,
	VERR_CR_ASSOC_RQST_LEN	= 2,
	VERR_CR_ASSOC_CMD	= 3,
	VERR_CR_ASSOC_CMD_LEN	= 4,
	VERR_ERSP_RATIO		= 5,
	VERR_ASSOC_ALLOC_FAIL	= 6,
	VERR_QUEUE_ALLOC_FAIL	= 7,
	VERR_CR_CONN_LEN	= 8,
	VERR_CR_CONN_RQST_LEN	= 9,
	VERR_ASSOC_ID		= 10,
	VERR_ASSOC_ID_LEN	= 11,
	VERR_NO_ASSOC		= 12,
	VERR_CONN_ID		= 13,
	VERR_CONN_ID_LEN	= 14,
	VERR_NO_CONN		= 15,
	VERR_CR_CONN_CMD	= 16,
	VERR_CR_CONN_CMD_LEN	= 17,
	VERR_DISCONN_LEN	= 18,
	VERR_DISCONN_RQST_LEN	= 19,
	VERR_DISCONN_CMD	= 20,
	VERR_DISCONN_CMD_LEN	= 21,
	VERR_DISCONN_SCOPE	= 22,
	VERR_RS_LEN		= 23,
	VERR_RS_RQST_LEN	= 24,
	VERR_RS_CMD		= 25,
	VERR_RS_CMD_LEN		= 26,
	VERR_RS_RCTL		= 27,
	VERR_RS_RO		= 28,
};

static char *validation_errors[] = {
	"OK",
	"Bad CR_ASSOC Length",
	"Bad CR_ASSOC Rqst Length",
	"Not CR_ASSOC Cmd",
	"Bad CR_ASSOC Cmd Length",
	"Bad Ersp Ratio",
	"Association Allocation Failed",
	"Queue Allocation Failed",
	"Bad CR_CONN Length",
	"Bad CR_CONN Rqst Length",
	"Not Association ID",
	"Bad Association ID Length",
	"No Association",
	"Not Connection ID",
	"Bad Connection ID Length",
	"No Connection",
	"Not CR_CONN Cmd",
	"Bad CR_CONN Cmd Length",
	"Bad DISCONN Length",
	"Bad DISCONN Rqst Length",
	"Not DISCONN Cmd",
	"Bad DISCONN Cmd Length",
	"Bad Disconnect Scope",
	"Bad RS Length",
	"Bad RS Rqst Length",
	"Not RS Cmd",
	"Bad RS Cmd Length",
	"Bad RS R_CTL",
	"Bad RS Relative Offset",
};

static void
nvmet_fc_ls_create_association(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_ls_iod *iod)
{
	struct fcnvme_ls_cr_assoc_rqst *rqst =
				(struct fcnvme_ls_cr_assoc_rqst *)iod->rqstbuf;
	struct fcnvme_ls_cr_assoc_acc *acc =
				(struct fcnvme_ls_cr_assoc_acc *)iod->rspbuf;
	struct nvmet_fc_tgt_queue *queue;
	int ret = 0;

	memset(acc, 0, sizeof(*acc));

	if (iod->rqstdatalen < sizeof(struct fcnvme_ls_cr_assoc_rqst))
		ret = VERR_CR_ASSOC_LEN;
	else if (rqst->desc_list_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_ls_cr_assoc_rqst)))
		ret = VERR_CR_ASSOC_RQST_LEN;
	else if (rqst->assoc_cmd.desc_tag !=
			cpu_to_be32(FCNVME_LSDESC_CREATE_ASSOC_CMD))
		ret = VERR_CR_ASSOC_CMD;
	else if (rqst->assoc_cmd.desc_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_cr_assoc_cmd)))
		ret = VERR_CR_ASSOC_CMD_LEN;
	else if (!rqst->assoc_cmd.ersp_ratio ||
		 (be16_to_cpu(rqst->assoc_cmd.ersp_ratio) >=
				be16_to_cpu(rqst->assoc_cmd.sqsize)))
		ret = VERR_ERSP_RATIO;

	else {
		/* new association w/ admin queue */
		iod->assoc = nvmet_fc_alloc_target_assoc(tgtport);
		if (!iod->assoc)
			ret = VERR_ASSOC_ALLOC_FAIL;
		else {
			queue = nvmet_fc_alloc_target_queue(iod->assoc, 0,
					be16_to_cpu(rqst->assoc_cmd.sqsize));
			if (!queue)
				ret = VERR_QUEUE_ALLOC_FAIL;
		}
	}

	if (ret) {
		dev_err(tgtport->dev,
			"Create Association LS failed: %s\n",
			validation_errors[ret]);
		iod->lsreq->rsplen = nvmet_fc_format_rjt(acc,
				NVME_FC_MAX_LS_BUFFER_SIZE, rqst->w0.ls_cmd,
				ELS_RJT_LOGIC,
				ELS_EXPL_NONE, 0);
		return;
	}

	queue->ersp_ratio = be16_to_cpu(rqst->assoc_cmd.ersp_ratio);
	atomic_set(&queue->connected, 1);
	queue->sqhd = 0;	/* best place to init value */

	/* format a response */

	iod->lsreq->rsplen = sizeof(*acc);

	nvmet_fc_format_rsp_hdr(acc, FCNVME_LS_ACC,
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_ls_cr_assoc_acc)),
			FCNVME_LS_CREATE_ASSOCIATION);
	acc->associd.desc_tag = cpu_to_be32(FCNVME_LSDESC_ASSOC_ID);
	acc->associd.desc_len =
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_assoc_id));
	acc->associd.association_id =
			cpu_to_be64(nvmet_fc_makeconnid(iod->assoc, 0));
	acc->connectid.desc_tag = cpu_to_be32(FCNVME_LSDESC_CONN_ID);
	acc->connectid.desc_len =
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_conn_id));
	acc->connectid.connection_id = acc->associd.association_id;
}

static void
nvmet_fc_ls_create_connection(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_ls_iod *iod)
{
	struct fcnvme_ls_cr_conn_rqst *rqst =
				(struct fcnvme_ls_cr_conn_rqst *)iod->rqstbuf;
	struct fcnvme_ls_cr_conn_acc *acc =
				(struct fcnvme_ls_cr_conn_acc *)iod->rspbuf;
	struct nvmet_fc_tgt_queue *queue;
	int ret = 0;

	memset(acc, 0, sizeof(*acc));

	if (iod->rqstdatalen < sizeof(struct fcnvme_ls_cr_conn_rqst))
		ret = VERR_CR_CONN_LEN;
	else if (rqst->desc_list_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_ls_cr_conn_rqst)))
		ret = VERR_CR_CONN_RQST_LEN;
	else if (rqst->associd.desc_tag != cpu_to_be32(FCNVME_LSDESC_ASSOC_ID))
		ret = VERR_ASSOC_ID;
	else if (rqst->associd.desc_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_assoc_id)))
		ret = VERR_ASSOC_ID_LEN;
	else if (rqst->connect_cmd.desc_tag !=
			cpu_to_be32(FCNVME_LSDESC_CREATE_CONN_CMD))
		ret = VERR_CR_CONN_CMD;
	else if (rqst->connect_cmd.desc_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_cr_conn_cmd)))
		ret = VERR_CR_CONN_CMD_LEN;
	else if (!rqst->connect_cmd.ersp_ratio ||
		 (be16_to_cpu(rqst->connect_cmd.ersp_ratio) >=
				be16_to_cpu(rqst->connect_cmd.sqsize)))
		ret = VERR_ERSP_RATIO;

	else {
		/* new io queue */
		iod->assoc = nvmet_fc_find_target_assoc(tgtport,
				be64_to_cpu(rqst->associd.association_id));
		if (!iod->assoc)
			ret = VERR_NO_ASSOC;
		else {
			queue = nvmet_fc_alloc_target_queue(iod->assoc,
					be16_to_cpu(rqst->connect_cmd.qid),
					be16_to_cpu(rqst->connect_cmd.sqsize));
			if (!queue)
				ret = VERR_QUEUE_ALLOC_FAIL;

			/* release get taken in nvmet_fc_find_target_assoc */
			nvmet_fc_tgt_a_put(iod->assoc);
		}
	}

	if (ret) {
		dev_err(tgtport->dev,
			"Create Connection LS failed: %s\n",
			validation_errors[ret]);
		iod->lsreq->rsplen = nvmet_fc_format_rjt(acc,
				NVME_FC_MAX_LS_BUFFER_SIZE, rqst->w0.ls_cmd,
				(ret == VERR_NO_ASSOC) ?
						ELS_RJT_PROT : ELS_RJT_LOGIC,
				ELS_EXPL_NONE, 0);
		return;
	}

	queue->ersp_ratio = be16_to_cpu(rqst->connect_cmd.ersp_ratio);
	atomic_set(&queue->connected, 1);
	queue->sqhd = 0;	/* best place to init value */

	/* format a response */

	iod->lsreq->rsplen = sizeof(*acc);

	nvmet_fc_format_rsp_hdr(acc, FCNVME_LS_ACC,
			fcnvme_lsdesc_len(sizeof(struct fcnvme_ls_cr_conn_acc)),
			FCNVME_LS_CREATE_CONNECTION);
	acc->connectid.desc_tag = cpu_to_be32(FCNVME_LSDESC_CONN_ID);
	acc->connectid.desc_len =
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_conn_id));
	acc->connectid.connection_id =
			cpu_to_be64(nvmet_fc_makeconnid(iod->assoc,
				be16_to_cpu(rqst->connect_cmd.qid)));
}

static void
nvmet_fc_ls_disconnect(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_ls_iod *iod)
{
	struct fcnvme_ls_disconnect_rqst *rqst =
			(struct fcnvme_ls_disconnect_rqst *)iod->rqstbuf;
	struct fcnvme_ls_disconnect_acc *acc =
			(struct fcnvme_ls_disconnect_acc *)iod->rspbuf;
	struct nvmet_fc_tgt_queue *queue = NULL;
	struct nvmet_fc_tgt_assoc *assoc;
	int ret = 0;
	bool del_assoc = false;

	memset(acc, 0, sizeof(*acc));

	if (iod->rqstdatalen < sizeof(struct fcnvme_ls_disconnect_rqst))
		ret = VERR_DISCONN_LEN;
	else if (rqst->desc_list_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_ls_disconnect_rqst)))
		ret = VERR_DISCONN_RQST_LEN;
	else if (rqst->associd.desc_tag != cpu_to_be32(FCNVME_LSDESC_ASSOC_ID))
		ret = VERR_ASSOC_ID;
	else if (rqst->associd.desc_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_assoc_id)))
		ret = VERR_ASSOC_ID_LEN;
	else if (rqst->discon_cmd.desc_tag !=
			cpu_to_be32(FCNVME_LSDESC_DISCONN_CMD))
		ret = VERR_DISCONN_CMD;
	else if (rqst->discon_cmd.desc_len !=
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_lsdesc_disconn_cmd)))
		ret = VERR_DISCONN_CMD_LEN;
	else if ((rqst->discon_cmd.scope != FCNVME_DISCONN_ASSOCIATION) &&
			(rqst->discon_cmd.scope != FCNVME_DISCONN_CONNECTION))
		ret = VERR_DISCONN_SCOPE;
	else {
		/* match an active association */
		assoc = nvmet_fc_find_target_assoc(tgtport,
				be64_to_cpu(rqst->associd.association_id));
		iod->assoc = assoc;
		if (assoc) {
			if (rqst->discon_cmd.scope ==
					FCNVME_DISCONN_CONNECTION) {
				queue = nvmet_fc_find_target_queue(tgtport,
						be64_to_cpu(
							rqst->discon_cmd.id));
				if (!queue) {
					nvmet_fc_tgt_a_put(assoc);
					ret = VERR_NO_CONN;
				}
			}
		} else
			ret = VERR_NO_ASSOC;
	}

	if (ret) {
		dev_err(tgtport->dev,
			"Disconnect LS failed: %s\n",
			validation_errors[ret]);
		iod->lsreq->rsplen = nvmet_fc_format_rjt(acc,
				NVME_FC_MAX_LS_BUFFER_SIZE, rqst->w0.ls_cmd,
				(ret == 8) ? ELS_RJT_PROT : ELS_RJT_LOGIC,
				ELS_EXPL_NONE, 0);
		return;
	}

	/* format a response */

	iod->lsreq->rsplen = sizeof(*acc);

	nvmet_fc_format_rsp_hdr(acc, FCNVME_LS_ACC,
			fcnvme_lsdesc_len(
				sizeof(struct fcnvme_ls_disconnect_acc)),
			FCNVME_LS_DISCONNECT);


	/* are we to delete a Connection ID (queue) */
	if (queue) {
		int qid = queue->qid;

		nvmet_fc_delete_target_queue(queue);

		/* release the get taken by find_target_queue */
		nvmet_fc_tgt_q_put(queue);

		/* tear association down if io queue terminated */
		if (!qid)
			del_assoc = true;
	}

	/* release get taken in nvmet_fc_find_target_assoc */
	nvmet_fc_tgt_a_put(iod->assoc);

	if (del_assoc)
		nvmet_fc_delete_target_assoc(iod->assoc);
}


/* *********************** NVME Ctrl Routines **************************** */


static void nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req);

static struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops;

static void
nvmet_fc_xmt_ls_rsp_done(struct nvmefc_tgt_ls_req *lsreq)
{
	struct nvmet_fc_ls_iod *iod = lsreq->nvmet_fc_private;
	struct nvmet_fc_tgtport *tgtport = iod->tgtport;

	fc_dma_sync_single_for_cpu(tgtport->dev, iod->rspdma,
				NVME_FC_MAX_LS_BUFFER_SIZE, DMA_TO_DEVICE);
	nvmet_fc_free_ls_iod(tgtport, iod);
	nvmet_fc_tgtport_put(tgtport);
}

static void
nvmet_fc_xmt_ls_rsp(struct nvmet_fc_tgtport *tgtport,
				struct nvmet_fc_ls_iod *iod)
{
	int ret;

	fc_dma_sync_single_for_device(tgtport->dev, iod->rspdma,
				  NVME_FC_MAX_LS_BUFFER_SIZE, DMA_TO_DEVICE);

	ret = tgtport->ops->xmt_ls_rsp(&tgtport->fc_target_port, iod->lsreq);
	if (ret)
		nvmet_fc_xmt_ls_rsp_done(iod->lsreq);
}

/*
 * Actual processing routine for received FC-NVME LS Requests from the LLD
 */
static void
nvmet_fc_handle_ls_rqst(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_ls_iod *iod)
{
	struct fcnvme_ls_rqst_w0 *w0 =
			(struct fcnvme_ls_rqst_w0 *)iod->rqstbuf;

	iod->lsreq->nvmet_fc_private = iod;
	iod->lsreq->rspbuf = iod->rspbuf;
	iod->lsreq->rspdma = iod->rspdma;
	iod->lsreq->done = nvmet_fc_xmt_ls_rsp_done;
	/* Be preventative. handlers will later set to valid length */
	iod->lsreq->rsplen = 0;

	iod->assoc = NULL;

	/*
	 * handlers:
	 *   parse request input, execute the request, and format the
	 *   LS response
	 */
	switch (w0->ls_cmd) {
	case FCNVME_LS_CREATE_ASSOCIATION:
		/* Creates Association and initial Admin Queue/Connection */
		nvmet_fc_ls_create_association(tgtport, iod);
		break;
	case FCNVME_LS_CREATE_CONNECTION:
		/* Creates an IO Queue/Connection */
		nvmet_fc_ls_create_connection(tgtport, iod);
		break;
	case FCNVME_LS_DISCONNECT:
		/* Terminate a Queue/Connection or the Association */
		nvmet_fc_ls_disconnect(tgtport, iod);
		break;
	default:
		iod->lsreq->rsplen = nvmet_fc_format_rjt(iod->rspbuf,
				NVME_FC_MAX_LS_BUFFER_SIZE, w0->ls_cmd,
				ELS_RJT_INVAL, ELS_EXPL_NONE, 0);
	}

	nvmet_fc_xmt_ls_rsp(tgtport, iod);
}

/*
 * Actual processing routine for received FC-NVME LS Requests from the LLD
 */
static void
nvmet_fc_handle_ls_rqst_work(struct work_struct *work)
{
	struct nvmet_fc_ls_iod *iod =
		container_of(work, struct nvmet_fc_ls_iod, work);
	struct nvmet_fc_tgtport *tgtport = iod->tgtport;

	nvmet_fc_handle_ls_rqst(tgtport, iod);
}


/**
 * nvmet_fc_rcv_ls_req - transport entry point called by an LLDD
 *                       upon the reception of a NVME LS request.
 *
 * The nvmet-fc layer will copy payload to an internal structure for
 * processing.  As such, upon completion of the routine, the LLDD may
 * immediately free/reuse the LS request buffer passed in the call.
 *
 * If this routine returns error, the LLDD should abort the exchange.
 *
 * @tgtport:    pointer to the (registered) target port the LS was
 *              received on.
 * @lsreq:      pointer to a lsreq request structure to be used to reference
 *              the exchange corresponding to the LS.
 * @lsreqbuf:   pointer to the buffer containing the LS Request
 * @lsreqbuf_len: length, in bytes, of the received LS request
 */
int
nvmet_fc_rcv_ls_req(struct nvmet_fc_target_port *target_port,
			struct nvmefc_tgt_ls_req *lsreq,
			void *lsreqbuf, u32 lsreqbuf_len)
{
	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
	struct nvmet_fc_ls_iod *iod;

	if (lsreqbuf_len > NVME_FC_MAX_LS_BUFFER_SIZE)
		return -E2BIG;

	if (!nvmet_fc_tgtport_get(tgtport))
		return -ESHUTDOWN;

	iod = nvmet_fc_alloc_ls_iod(tgtport);
	if (!iod) {
		nvmet_fc_tgtport_put(tgtport);
		return -ENOENT;
	}

	iod->lsreq = lsreq;
	iod->fcpreq = NULL;
	memcpy(iod->rqstbuf, lsreqbuf, lsreqbuf_len);
	iod->rqstdatalen = lsreqbuf_len;

	schedule_work(&iod->work);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmet_fc_rcv_ls_req);


/*
 * **********************
 * Start of FCP handling
 * **********************
 */

static int
nvmet_fc_alloc_tgt_pgs(struct nvmet_fc_fcp_iod *fod)
{
	struct scatterlist *sg;
	struct page *page;
	unsigned int nent;
	u32 page_len, length;
	int i = 0;

	length = fod->total_length;
	nent = DIV_ROUND_UP(length, PAGE_SIZE);
	sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
	if (!sg)
		goto out;

	sg_init_table(sg, nent);

	while (length) {
		page_len = min_t(u32, length, PAGE_SIZE);

		page = alloc_page(GFP_KERNEL);
		if (!page)
			goto out_free_pages;

		sg_set_page(&sg[i], page, page_len, 0);
		length -= page_len;
		i++;
	}

	fod->data_sg = sg;
	fod->data_sg_cnt = nent;
	fod->data_sg_cnt = fc_dma_map_sg(fod->tgtport->dev, sg, nent,
				((fod->io_dir == NVMET_FCP_WRITE) ?
					DMA_FROM_DEVICE : DMA_TO_DEVICE));
				/* note: write from initiator perspective */

	return 0;

out_free_pages:
	while (i > 0) {
		i--;
		__free_page(sg_page(&sg[i]));
	}
	kfree(sg);
	fod->data_sg = NULL;
	fod->data_sg_cnt = 0;
out:
	return NVME_SC_INTERNAL;
}

static void
nvmet_fc_free_tgt_pgs(struct nvmet_fc_fcp_iod *fod)
{
	struct scatterlist *sg;
	int count;

	if (!fod->data_sg || !fod->data_sg_cnt)
		return;

	fc_dma_unmap_sg(fod->tgtport->dev, fod->data_sg, fod->data_sg_cnt,
				((fod->io_dir == NVMET_FCP_WRITE) ?
					DMA_FROM_DEVICE : DMA_TO_DEVICE));
	for_each_sg(fod->data_sg, sg, fod->data_sg_cnt, count)
		__free_page(sg_page(sg));
	kfree(fod->data_sg);
}


static bool
queue_90percent_full(struct nvmet_fc_tgt_queue *q, u32 sqhd)
{
	u32 sqtail, used;

	/* egad, this is ugly. And sqtail is just a best guess */
	sqtail = atomic_read(&q->sqtail) % q->sqsize;

	used = (sqtail < sqhd) ? (sqtail + q->sqsize - sqhd) : (sqtail - sqhd);
	return ((used * 10) >= (((u32)(q->sqsize - 1) * 9)));
}

/*
 * Prep RSP payload.
 * May be a NVMET_FCOP_RSP or NVMET_FCOP_READDATA_RSP op
 */
static void
nvmet_fc_prep_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
				struct nvmet_fc_fcp_iod *fod)
{
	struct nvme_fc_ersp_iu *ersp = &fod->rspiubuf;
	struct nvme_common_command *sqe = &fod->cmdiubuf.sqe.common;
	struct nvme_completion *cqe = &ersp->cqe;
	u32 *cqewd = (u32 *)cqe;
	bool send_ersp = false;
	u32 rsn, rspcnt, xfr_length;

	if (fod->fcpreq->op == NVMET_FCOP_READDATA_RSP)
		xfr_length = fod->total_length;
	else
		xfr_length = fod->offset;

	/*
	 * check to see if we can send a 0's rsp.
	 *   Note: to send a 0's response, the NVME-FC host transport will
	 *   recreate the CQE. The host transport knows: sq id, SQHD (last
	 *   seen in an ersp), and command_id. Thus it will create a
	 *   zero-filled CQE with those known fields filled in. Transport
	 *   must send an ersp for any condition where the cqe won't match
	 *   this.
	 *
	 * Here are the FC-NVME mandated cases where we must send an ersp:
	 *  every N responses, where N=ersp_ratio
	 *  force fabric commands to send ersp's (not in FC-NVME but good
	 *    practice)
	 *  normal cmds: any time status is non-zero, or status is zero
	 *     but words 0 or 1 are non-zero.
	 *  the SQ is 90% or more full
	 *  the cmd is a fused command
	 *  transferred data length not equal to cmd iu length
	 */
	rspcnt = atomic_inc_return(&fod->queue->zrspcnt);
	if (!(rspcnt % fod->queue->ersp_ratio) ||
	    sqe->opcode == nvme_fabrics_command ||
	    xfr_length != fod->total_length ||
	    (le16_to_cpu(cqe->status) & 0xFFFE) || cqewd[0] || cqewd[1] ||
	    (sqe->flags & (NVME_CMD_FUSE_FIRST | NVME_CMD_FUSE_SECOND)) ||
	    queue_90percent_full(fod->queue, cqe->sq_head))
		send_ersp = true;

	/* re-set the fields */
	fod->fcpreq->rspaddr = ersp;
	fod->fcpreq->rspdma = fod->rspdma;

	if (!send_ersp) {
		memset(ersp, 0, NVME_FC_SIZEOF_ZEROS_RSP);
		fod->fcpreq->rsplen = NVME_FC_SIZEOF_ZEROS_RSP;
	} else {
		ersp->iu_len = cpu_to_be16(sizeof(*ersp)/sizeof(u32));
		rsn = atomic_inc_return(&fod->queue->rsn);
		ersp->rsn = cpu_to_be32(rsn);
		ersp->xfrd_len = cpu_to_be32(xfr_length);
		fod->fcpreq->rsplen = sizeof(*ersp);
	}

	fc_dma_sync_single_for_device(tgtport->dev, fod->rspdma,
				  sizeof(fod->rspiubuf), DMA_TO_DEVICE);
}

static void nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq);

static void
nvmet_fc_xmt_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
				struct nvmet_fc_fcp_iod *fod)
{
	int ret;

	fod->fcpreq->op = NVMET_FCOP_RSP;
	fod->fcpreq->timeout = 0;

	nvmet_fc_prep_fcp_rsp(tgtport, fod);

	ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fod->fcpreq);
	if (ret)
		nvmet_fc_abort_op(tgtport, fod->fcpreq);
}

static void
nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
				struct nvmet_fc_fcp_iod *fod, u8 op)
{
	struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
	struct scatterlist *sg, *datasg;
	u32 tlen, sg_off;
	int ret;

	fcpreq->op = op;
	fcpreq->offset = fod->offset;
	fcpreq->timeout = NVME_FC_TGTOP_TIMEOUT_SEC;
	tlen = min_t(u32, (NVMET_FC_MAX_KB_PER_XFR * 1024),
			(fod->total_length - fod->offset));
	tlen = min_t(u32, tlen, NVME_FC_MAX_SEGMENTS * PAGE_SIZE);
	tlen = min_t(u32, tlen, fod->tgtport->ops->max_sgl_segments
					* PAGE_SIZE);
	fcpreq->transfer_length = tlen;
	fcpreq->transferred_length = 0;
	fcpreq->fcp_error = 0;
	fcpreq->rsplen = 0;

	fcpreq->sg_cnt = 0;

	datasg = fod->next_sg;
	sg_off = fod->next_sg_offset;

	for (sg = fcpreq->sg ; tlen; sg++) {
		*sg = *datasg;
		if (sg_off) {
			sg->offset += sg_off;
			sg->length -= sg_off;
			sg->dma_address += sg_off;
			sg_off = 0;
		}
		if (tlen < sg->length) {
			sg->length = tlen;
			fod->next_sg = datasg;
			fod->next_sg_offset += tlen;
		} else if (tlen == sg->length) {
			fod->next_sg_offset = 0;
			fod->next_sg = sg_next(datasg);
		} else {
			fod->next_sg_offset = 0;
			datasg = sg_next(datasg);
		}
		tlen -= sg->length;
		fcpreq->sg_cnt++;
	}

	/*
	 * If the last READDATA request: check if LLDD supports
	 * combined xfr with response.
	 */
	if ((op == NVMET_FCOP_READDATA) &&
	    ((fod->offset + fcpreq->transfer_length) == fod->total_length) &&
	    (tgtport->ops->target_features & NVMET_FCTGTFEAT_READDATA_RSP)) {
		fcpreq->op = NVMET_FCOP_READDATA_RSP;
		nvmet_fc_prep_fcp_rsp(tgtport, fod);
	}

	ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fod->fcpreq);
	if (ret) {
		/*
		 * should be ok to set w/o lock as its in the thread of
		 * execution (not an async timer routine) and doesn't
		 * contend with any clearing action
		 */
		fod->abort = true;

		if (op == NVMET_FCOP_WRITEDATA)
			nvmet_req_complete(&fod->req,
					NVME_SC_FC_TRANSPORT_ERROR);
		else /* NVMET_FCOP_READDATA or NVMET_FCOP_READDATA_RSP */ {
			fcpreq->fcp_error = ret;
			fcpreq->transferred_length = 0;
			nvmet_fc_xmt_fcp_op_done(fod->fcpreq);
		}
	}
}

static void
nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq)
{
	struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
	struct nvmet_fc_tgtport *tgtport = fod->tgtport;
	unsigned long flags;
	bool abort;

	spin_lock_irqsave(&fod->flock, flags);
	abort = fod->abort;
	spin_unlock_irqrestore(&fod->flock, flags);

	/* if in the middle of an io and we need to tear down */
	if (abort && fcpreq->op != NVMET_FCOP_ABORT) {
		/* data no longer needed */
		nvmet_fc_free_tgt_pgs(fod);

		if (fcpreq->fcp_error || abort)
			nvmet_req_complete(&fod->req, fcpreq->fcp_error);

		return;
	}

	switch (fcpreq->op) {

	case NVMET_FCOP_WRITEDATA:
		if (abort || fcpreq->fcp_error ||
		    fcpreq->transferred_length != fcpreq->transfer_length) {
			nvmet_req_complete(&fod->req,
					NVME_SC_FC_TRANSPORT_ERROR);
			return;
		}

		fod->offset += fcpreq->transferred_length;
		if (fod->offset != fod->total_length) {
			/* transfer the next chunk */
			nvmet_fc_transfer_fcp_data(tgtport, fod,
						NVMET_FCOP_WRITEDATA);
			return;
		}

		/* data transfer complete, resume with nvmet layer */

		fod->req.execute(&fod->req);

		break;

	case NVMET_FCOP_READDATA:
	case NVMET_FCOP_READDATA_RSP:
		if (abort || fcpreq->fcp_error ||
		    fcpreq->transferred_length != fcpreq->transfer_length) {
			/* data no longer needed */
			nvmet_fc_free_tgt_pgs(fod);

			nvmet_fc_abort_op(tgtport, fod->fcpreq);
			return;
		}

		/* success */

		if (fcpreq->op == NVMET_FCOP_READDATA_RSP) {
			/* data no longer needed */
			nvmet_fc_free_tgt_pgs(fod);
			fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
					sizeof(fod->rspiubuf), DMA_TO_DEVICE);
			nvmet_fc_free_fcp_iod(fod->queue, fod);
			return;
		}

		fod->offset += fcpreq->transferred_length;
		if (fod->offset != fod->total_length) {
			/* transfer the next chunk */
			nvmet_fc_transfer_fcp_data(tgtport, fod,
						NVMET_FCOP_READDATA);
			return;
		}

		/* data transfer complete, send response */

		/* data no longer needed */
		nvmet_fc_free_tgt_pgs(fod);

		nvmet_fc_xmt_fcp_rsp(tgtport, fod);

		break;

	case NVMET_FCOP_RSP:
	case NVMET_FCOP_ABORT:
		fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
				sizeof(fod->rspiubuf), DMA_TO_DEVICE);
		nvmet_fc_free_fcp_iod(fod->queue, fod);
		break;

	default:
		nvmet_fc_free_tgt_pgs(fod);
		nvmet_fc_abort_op(tgtport, fod->fcpreq);
		break;
	}
}

/*
 * actual completion handler after execution by the nvmet layer
 */
static void
__nvmet_fc_fcp_nvme_cmd_done(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_fcp_iod *fod, int status)
{
	struct nvme_common_command *sqe = &fod->cmdiubuf.sqe.common;
	struct nvme_completion *cqe = &fod->rspiubuf.cqe;
	unsigned long flags;
	bool abort;

	spin_lock_irqsave(&fod->flock, flags);
	abort = fod->abort;
	spin_unlock_irqrestore(&fod->flock, flags);

	/* if we have a CQE, snoop the last sq_head value */
	if (!status)
		fod->queue->sqhd = cqe->sq_head;

	if (abort) {
		/* data no longer needed */
		nvmet_fc_free_tgt_pgs(fod);

		nvmet_fc_abort_op(tgtport, fod->fcpreq);
		return;
	}

	/* if an error handling the cmd post initial parsing */
	if (status) {
		/* fudge up a failed CQE status for our transport error */
		memset(cqe, 0, sizeof(*cqe));
		cqe->sq_head = fod->queue->sqhd;	/* echo last cqe sqhd */
		cqe->sq_id = cpu_to_le16(fod->queue->qid);
		cqe->command_id = sqe->command_id;
		cqe->status = cpu_to_le16(status);
	} else {

		/*
		 * try to push the data even if the SQE status is non-zero.
		 * There may be a status where data still was intended to
		 * be moved
		 */
		if ((fod->io_dir == NVMET_FCP_READ) && (fod->data_sg_cnt)) {
			/* push the data over before sending rsp */
			nvmet_fc_transfer_fcp_data(tgtport, fod,
						NVMET_FCOP_READDATA);
			return;
		}

		/* writes & no data - fall thru */
	}

	/* data no longer needed */
	nvmet_fc_free_tgt_pgs(fod);

	nvmet_fc_xmt_fcp_rsp(tgtport, fod);
}


static void
nvmet_fc_fcp_nvme_cmd_done(struct nvmet_req *nvme_req)
{
	struct nvmet_fc_fcp_iod *fod = nvmet_req_to_fod(nvme_req);
	struct nvmet_fc_tgtport *tgtport = fod->tgtport;

	__nvmet_fc_fcp_nvme_cmd_done(tgtport, fod, 0);
}


/*
 * Actual processing routine for received FC-NVME LS Requests from the LLD
 */
void
nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
			struct nvmet_fc_fcp_iod *fod)
{
	struct nvme_fc_cmd_iu *cmdiu = &fod->cmdiubuf;
	int ret;

	/*
	 * Fused commands are currently not supported in the linux
	 * implementation.
	 *
	 * As such, the implementation of the FC transport does not
	 * look at the fused commands and order delivery to the upper
	 * layer until we have both based on csn.
	 */

	fod->fcpreq->done = nvmet_fc_xmt_fcp_op_done;

	fod->total_length = be32_to_cpu(cmdiu->data_len);
	if (cmdiu->flags & FCNVME_CMD_FLAGS_WRITE) {
		fod->io_dir = NVMET_FCP_WRITE;
		if (!nvme_is_write(&cmdiu->sqe))
			goto transport_error;
	} else if (cmdiu->flags & FCNVME_CMD_FLAGS_READ) {
		fod->io_dir = NVMET_FCP_READ;
		if (nvme_is_write(&cmdiu->sqe))
			goto transport_error;
	} else {
		fod->io_dir = NVMET_FCP_NODATA;
		if (fod->total_length)
			goto transport_error;
	}

	fod->req.cmd = &fod->cmdiubuf.sqe;
	fod->req.rsp = &fod->rspiubuf.cqe;
	fod->req.port = fod->queue->port;

	/* ensure nvmet handlers will set cmd handler callback */
	fod->req.execute = NULL;

	/* clear any response payload */
	memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));

	ret = nvmet_req_init(&fod->req,
				&fod->queue->nvme_cq,
				&fod->queue->nvme_sq,
				&nvmet_fc_tgt_fcp_ops);
	if (!ret) {	/* bad SQE content */
		nvmet_fc_abort_op(tgtport, fod->fcpreq);
		return;
	}

	/* keep a running counter of tail position */
	atomic_inc(&fod->queue->sqtail);

	fod->data_sg = NULL;
	fod->data_sg_cnt = 0;
	if (fod->total_length) {
		ret = nvmet_fc_alloc_tgt_pgs(fod);
		if (ret) {
			nvmet_req_complete(&fod->req, ret);
			return;
		}
	}
	fod->req.sg = fod->data_sg;
	fod->req.sg_cnt = fod->data_sg_cnt;
	fod->offset = 0;
	fod->next_sg = fod->data_sg;
	fod->next_sg_offset = 0;

	if (fod->io_dir == NVMET_FCP_WRITE) {
		/* pull the data over before invoking nvmet layer */
		nvmet_fc_transfer_fcp_data(tgtport, fod, NVMET_FCOP_WRITEDATA);
		return;
	}

	/*
	 * Reads or no data:
	 *
	 * can invoke the nvmet_layer now. If read data, cmd completion will
	 * push the data
	 */

	fod->req.execute(&fod->req);

	return;

transport_error:
	nvmet_fc_abort_op(tgtport, fod->fcpreq);
}

/*
 * Actual processing routine for received FC-NVME LS Requests from the LLD
 */
static void
nvmet_fc_handle_fcp_rqst_work(struct work_struct *work)
{
	struct nvmet_fc_fcp_iod *fod =
		container_of(work, struct nvmet_fc_fcp_iod, work);
	struct nvmet_fc_tgtport *tgtport = fod->tgtport;

	nvmet_fc_handle_fcp_rqst(tgtport, fod);
}

/**
 * nvmet_fc_rcv_fcp_req - transport entry point called by an LLDD
 *                       upon the reception of a NVME FCP CMD IU.
 *
 * Pass a FC-NVME FCP CMD IU received from the FC link to the nvmet-fc
 * layer for processing.
 *
 * The nvmet-fc layer will copy cmd payload to an internal structure for
 * processing.  As such, upon completion of the routine, the LLDD may
 * immediately free/reuse the CMD IU buffer passed in the call.
 *
 * If this routine returns error, the lldd should abort the exchange.
 *
 * @target_port: pointer to the (registered) target port the FCP CMD IU
 *              was receive on.
 * @fcpreq:     pointer to a fcpreq request structure to be used to reference
 *              the exchange corresponding to the FCP Exchange.
 * @cmdiubuf:   pointer to the buffer containing the FCP CMD IU
 * @cmdiubuf_len: length, in bytes, of the received FCP CMD IU
 */
int
nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
			struct nvmefc_tgt_fcp_req *fcpreq,
			void *cmdiubuf, u32 cmdiubuf_len)
{
	struct nvmet_fc_tgtport *tgtport = targetport_to_tgtport(target_port);
	struct nvme_fc_cmd_iu *cmdiu = cmdiubuf;
	struct nvmet_fc_tgt_queue *queue;
	struct nvmet_fc_fcp_iod *fod;

	/* validate iu, so the connection id can be used to find the queue */
	if ((cmdiubuf_len != sizeof(*cmdiu)) ||
			(cmdiu->scsi_id != NVME_CMD_SCSI_ID) ||
			(cmdiu->fc_id != NVME_CMD_FC_ID) ||
			(be16_to_cpu(cmdiu->iu_len) != (sizeof(*cmdiu)/4)))
		return -EIO;


	queue = nvmet_fc_find_target_queue(tgtport,
				be64_to_cpu(cmdiu->connection_id));
	if (!queue)
		return -ENOTCONN;

	/*
	 * note: reference taken by find_target_queue
	 * After successful fod allocation, the fod will inherit the
	 * ownership of that reference and will remove the reference
	 * when the fod is freed.
	 */

	fod = nvmet_fc_alloc_fcp_iod(queue);
	if (!fod) {
		/* release the queue lookup reference */
		nvmet_fc_tgt_q_put(queue);
		return -ENOENT;
	}

	fcpreq->nvmet_fc_private = fod;
	fod->fcpreq = fcpreq;
	/*
	 * put all admin cmds on hw queue id 0. All io commands go to
	 * the respective hw queue based on a modulo basis
	 */
	fcpreq->hwqid = queue->qid ?
			((queue->qid - 1) % tgtport->ops->max_hw_queues) : 0;
	memcpy(&fod->cmdiubuf, cmdiubuf, cmdiubuf_len);

	queue_work_on(queue->cpu, queue->work_q, &fod->work);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_req);

enum {
	FCT_TRADDR_ERR		= 0,
	FCT_TRADDR_WWNN		= 1 << 0,
	FCT_TRADDR_WWPN		= 1 << 1,
};

struct nvmet_fc_traddr {
	u64	nn;
	u64	pn;
};

static const match_table_t traddr_opt_tokens = {
	{ FCT_TRADDR_WWNN,	"nn-%s"		},
	{ FCT_TRADDR_WWPN,	"pn-%s"		},
	{ FCT_TRADDR_ERR,	NULL		}
};

static int
nvmet_fc_parse_traddr(struct nvmet_fc_traddr *traddr, char *buf)
{
	substring_t args[MAX_OPT_ARGS];
	char *options, *o, *p;
	int token, ret = 0;
	u64 token64;

	options = o = kstrdup(buf, GFP_KERNEL);
	if (!options)
		return -ENOMEM;

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

		token = match_token(p, traddr_opt_tokens, args);
		switch (token) {
		case FCT_TRADDR_WWNN:
			if (match_u64(args, &token64)) {
				ret = -EINVAL;
				goto out;
			}
			traddr->nn = token64;
			break;
		case FCT_TRADDR_WWPN:
			if (match_u64(args, &token64)) {
				ret = -EINVAL;
				goto out;
			}
			traddr->pn = token64;
			break;
		default:
			pr_warn("unknown traddr token or missing value '%s'\n",
					p);
			ret = -EINVAL;
			goto out;
		}
	}

out:
	kfree(options);
	return ret;
}

static int
nvmet_fc_add_port(struct nvmet_port *port)
{
	struct nvmet_fc_tgtport *tgtport;
	struct nvmet_fc_traddr traddr = { 0L, 0L };
	unsigned long flags;
	int ret;

	/* validate the address info */
	if ((port->disc_addr.trtype != NVMF_TRTYPE_FC) ||
	    (port->disc_addr.adrfam != NVMF_ADDR_FAMILY_FC))
		return -EINVAL;

	/* map the traddr address info to a target port */

	ret = nvmet_fc_parse_traddr(&traddr, port->disc_addr.traddr);
	if (ret)
		return ret;

	ret = -ENXIO;
	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
	list_for_each_entry(tgtport, &nvmet_fc_target_list, tgt_list) {
		if ((tgtport->fc_target_port.node_name == traddr.nn) &&
		    (tgtport->fc_target_port.port_name == traddr.pn)) {
			/* a FC port can only be 1 nvmet port id */
			if (!tgtport->port) {
				tgtport->port = port;
				port->priv = tgtport;
				ret = 0;
			} else
				ret = -EALREADY;
			break;
		}
	}
	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
	return ret;
}

static void
nvmet_fc_remove_port(struct nvmet_port *port)
{
	struct nvmet_fc_tgtport *tgtport = port->priv;
	unsigned long flags;

	spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
	if (tgtport->port == port) {
		nvmet_fc_tgtport_put(tgtport);
		tgtport->port = NULL;
	}
	spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
}

static struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
	.owner			= THIS_MODULE,
	.type			= NVMF_TRTYPE_FC,
	.msdbd			= 1,
	.add_port		= nvmet_fc_add_port,
	.remove_port		= nvmet_fc_remove_port,
	.queue_response		= nvmet_fc_fcp_nvme_cmd_done,
	.delete_ctrl		= nvmet_fc_delete_ctrl,
};

static int __init nvmet_fc_init_module(void)
{
	return nvmet_register_transport(&nvmet_fc_tgt_fcp_ops);
}

static void __exit nvmet_fc_exit_module(void)
{
	/* sanity check - all lports should be removed */
	if (!list_empty(&nvmet_fc_target_list))
		pr_warn("%s: targetport list not empty\n", __func__);

	nvmet_unregister_transport(&nvmet_fc_tgt_fcp_ops);

	ida_destroy(&nvmet_fc_tgtport_cnt);
}

module_init(nvmet_fc_init_module);
module_exit(nvmet_fc_exit_module);

MODULE_LICENSE("GPL v2");