summaryrefslogtreecommitdiffstats
path: root/drivers/scsi/libfc/fc_fcp.c
blob: 2a631d7dbcec9c4664ef5d7cb5e206ea36a232ec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
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
/*
 * Copyright(c) 2007 Intel Corporation. All rights reserved.
 * Copyright(c) 2008 Red Hat, Inc.  All rights reserved.
 * Copyright(c) 2008 Mike Christie
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Maintained at www.Open-FCoE.org
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/scatterlist.h>
#include <linux/err.h>
#include <linux/crc32.h>

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

#include <scsi/fc/fc_fc2.h>

#include <scsi/libfc.h>
#include <scsi/fc_encode.h>

MODULE_AUTHOR("Open-FCoE.org");
MODULE_DESCRIPTION("libfc");
MODULE_LICENSE("GPL");

static int fc_fcp_debug;

#define FC_DEBUG_FCP(fmt...)			\
	do {					\
		if (fc_fcp_debug)		\
			FC_DBG(fmt);		\
	} while (0)

static struct kmem_cache *scsi_pkt_cachep;

/* SRB state definitions */
#define FC_SRB_FREE		0		/* cmd is free */
#define FC_SRB_CMD_SENT		(1 << 0)	/* cmd has been sent */
#define FC_SRB_RCV_STATUS	(1 << 1)	/* response has arrived */
#define FC_SRB_ABORT_PENDING	(1 << 2)	/* cmd abort sent to device */
#define FC_SRB_ABORTED		(1 << 3)	/* abort acknowleged */
#define FC_SRB_DISCONTIG	(1 << 4)	/* non-sequential data recvd */
#define FC_SRB_COMPL		(1 << 5)	/* fc_io_compl has been run */
#define FC_SRB_FCP_PROCESSING_TMO (1 << 6)	/* timer function processing */
#define FC_SRB_NOMEM		(1 << 7)	/* dropped to out of mem */

#define FC_SRB_READ		(1 << 1)
#define FC_SRB_WRITE		(1 << 0)

/*
 * The SCp.ptr should be tested and set under the host lock. NULL indicates
 * that the command has been retruned to the scsi layer.
 */
#define CMD_SP(Cmnd)		    ((struct fc_fcp_pkt *)(Cmnd)->SCp.ptr)
#define CMD_ENTRY_STATUS(Cmnd)	    ((Cmnd)->SCp.have_data_in)
#define CMD_COMPL_STATUS(Cmnd)	    ((Cmnd)->SCp.this_residual)
#define CMD_SCSI_STATUS(Cmnd)	    ((Cmnd)->SCp.Status)
#define CMD_RESID_LEN(Cmnd)	    ((Cmnd)->SCp.buffers_residual)

struct fc_fcp_internal {
	mempool_t	*scsi_pkt_pool;
	struct list_head scsi_pkt_queue;
	u8		throttled;
};

#define fc_get_scsi_internal(x)	((struct fc_fcp_internal *)(x)->scsi_priv)

/*
 * function prototypes
 * FC scsi I/O related functions
 */
static void fc_fcp_recv_data(struct fc_fcp_pkt *, struct fc_frame *);
static void fc_fcp_recv(struct fc_seq *, struct fc_frame *, void *);
static void fc_fcp_resp(struct fc_fcp_pkt *, struct fc_frame *);
static void fc_fcp_complete_locked(struct fc_fcp_pkt *);
static void fc_tm_done(struct fc_seq *, struct fc_frame *, void *);
static void fc_fcp_error(struct fc_fcp_pkt *fsp, struct fc_frame *fp);
static void fc_timeout_error(struct fc_fcp_pkt *);
static void fc_fcp_timeout(unsigned long data);
static void fc_fcp_rec(struct fc_fcp_pkt *);
static void fc_fcp_rec_error(struct fc_fcp_pkt *, struct fc_frame *);
static void fc_fcp_rec_resp(struct fc_seq *, struct fc_frame *, void *);
static void fc_io_compl(struct fc_fcp_pkt *);

static void fc_fcp_srr(struct fc_fcp_pkt *, enum fc_rctl, u32);
static void fc_fcp_srr_resp(struct fc_seq *, struct fc_frame *, void *);
static void fc_fcp_srr_error(struct fc_fcp_pkt *, struct fc_frame *);

/*
 * command status codes
 */
#define FC_COMPLETE		0
#define FC_CMD_ABORTED		1
#define FC_CMD_RESET		2
#define FC_CMD_PLOGO		3
#define FC_SNS_RCV		4
#define FC_TRANS_ERR		5
#define FC_DATA_OVRRUN		6
#define FC_DATA_UNDRUN		7
#define FC_ERROR		8
#define FC_HRD_ERROR		9
#define FC_CMD_TIME_OUT		10

/*
 * Error recovery timeout values.
 */
#define FC_SCSI_ER_TIMEOUT	(10 * HZ)
#define FC_SCSI_TM_TOV		(10 * HZ)
#define FC_SCSI_REC_TOV		(2 * HZ)
#define FC_HOST_RESET_TIMEOUT	(30 * HZ)

#define FC_MAX_ERROR_CNT	5
#define FC_MAX_RECOV_RETRY	3

#define FC_FCP_DFLT_QUEUE_DEPTH 32

/**
 * fc_fcp_pkt_alloc - allocation routine for scsi_pkt packet
 * @lp:		fc lport struct
 * @gfp:	gfp flags for allocation
 *
 * This is used by upper layer scsi driver.
 * Return Value : scsi_pkt structure or null on allocation failure.
 * Context	: call from process context. no locking required.
 */
static struct fc_fcp_pkt *fc_fcp_pkt_alloc(struct fc_lport *lp, gfp_t gfp)
{
	struct fc_fcp_internal *si = fc_get_scsi_internal(lp);
	struct fc_fcp_pkt *fsp;

	fsp = mempool_alloc(si->scsi_pkt_pool, gfp);
	if (fsp) {
		memset(fsp, 0, sizeof(*fsp));
		fsp->lp = lp;
		atomic_set(&fsp->ref_cnt, 1);
		init_timer(&fsp->timer);
		INIT_LIST_HEAD(&fsp->list);
		spin_lock_init(&fsp->scsi_pkt_lock);
	}
	return fsp;
}

/**
 * fc_fcp_pkt_release() - release hold on scsi_pkt packet
 * @fsp:	fcp packet struct
 *
 * This is used by upper layer scsi driver.
 * Context	: call from process  and interrupt context.
 *		  no locking required
 */
static void fc_fcp_pkt_release(struct fc_fcp_pkt *fsp)
{
	if (atomic_dec_and_test(&fsp->ref_cnt)) {
		struct fc_fcp_internal *si = fc_get_scsi_internal(fsp->lp);

		mempool_free(fsp, si->scsi_pkt_pool);
	}
}

static void fc_fcp_pkt_hold(struct fc_fcp_pkt *fsp)
{
	atomic_inc(&fsp->ref_cnt);
}

/**
 * fc_fcp_pkt_destory() - release hold on scsi_pkt packet
 * @seq:		exchange sequence
 * @fsp:	fcp packet struct
 *
 * Release hold on scsi_pkt packet set to keep scsi_pkt
 * till EM layer exch resource is not freed.
 * Context	: called from from EM layer.
 *		  no locking required
 */
static void fc_fcp_pkt_destroy(struct fc_seq *seq, void *fsp)
{
	fc_fcp_pkt_release(fsp);
}

/**
 * fc_fcp_lock_pkt() - lock a packet and get a ref to it.
 * @fsp:	fcp packet
 *
 * We should only return error if we return a command to scsi-ml before
 * getting a response. This can happen in cases where we send a abort, but
 * do not wait for the response and the abort and command can be passing
 * each other on the wire/network-layer.
 *
 * Note: this function locks the packet and gets a reference to allow
 * callers to call the completion function while the lock is held and
 * not have to worry about the packets refcount.
 *
 * TODO: Maybe we should just have callers grab/release the lock and
 * have a function that they call to verify the fsp and grab a ref if
 * needed.
 */
static inline int fc_fcp_lock_pkt(struct fc_fcp_pkt *fsp)
{
	spin_lock_bh(&fsp->scsi_pkt_lock);
	if (fsp->state & FC_SRB_COMPL) {
		spin_unlock_bh(&fsp->scsi_pkt_lock);
		return -EPERM;
	}

	fc_fcp_pkt_hold(fsp);
	return 0;
}

static inline void fc_fcp_unlock_pkt(struct fc_fcp_pkt *fsp)
{
	spin_unlock_bh(&fsp->scsi_pkt_lock);
	fc_fcp_pkt_release(fsp);
}

static void fc_fcp_timer_set(struct fc_fcp_pkt *fsp, unsigned long delay)
{
	if (!(fsp->state & FC_SRB_COMPL))
		mod_timer(&fsp->timer, jiffies + delay);
}

static int fc_fcp_send_abort(struct fc_fcp_pkt *fsp)
{
	if (!fsp->seq_ptr)
		return -EINVAL;

	fsp->state |= FC_SRB_ABORT_PENDING;
	return fsp->lp->tt.seq_exch_abort(fsp->seq_ptr, 0);
}

/*
 * Retry command.
 * An abort isn't needed.
 */
static void fc_fcp_retry_cmd(struct fc_fcp_pkt *fsp)
{
	if (fsp->seq_ptr) {
		fsp->lp->tt.exch_done(fsp->seq_ptr);
		fsp->seq_ptr = NULL;
	}

	fsp->state &= ~FC_SRB_ABORT_PENDING;
	fsp->io_status = SUGGEST_RETRY << 24;
	fsp->status_code = FC_ERROR;
	fc_fcp_complete_locked(fsp);
}

/*
 * Receive SCSI data from target.
 * Called after receiving solicited data.
 */
static void fc_fcp_recv_data(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
{
	struct scsi_cmnd *sc = fsp->cmd;
	struct fc_lport *lp = fsp->lp;
	struct fcoe_dev_stats *stats;
	struct fc_frame_header *fh;
	size_t start_offset;
	size_t offset;
	u32 crc;
	u32 copy_len = 0;
	size_t len;
	void *buf;
	struct scatterlist *sg;
	size_t remaining;

	fh = fc_frame_header_get(fp);
	offset = ntohl(fh->fh_parm_offset);
	start_offset = offset;
	len = fr_len(fp) - sizeof(*fh);
	buf = fc_frame_payload_get(fp, 0);

	if (offset + len > fsp->data_len) {
		/* this should never happen */
		if ((fr_flags(fp) & FCPHF_CRC_UNCHECKED) &&
		    fc_frame_crc_check(fp))
			goto crc_err;
		FC_DEBUG_FCP("data received past end. len %zx offset %zx "
			     "data_len %x\n", len, offset, fsp->data_len);
		fc_fcp_retry_cmd(fsp);
		return;
	}
	if (offset != fsp->xfer_len)
		fsp->state |= FC_SRB_DISCONTIG;

	crc = 0;
	if (fr_flags(fp) & FCPHF_CRC_UNCHECKED)
		crc = crc32(~0, (u8 *) fh, sizeof(*fh));

	sg = scsi_sglist(sc);
	remaining = len;

	while (remaining > 0 && sg) {
		size_t off;
		void *page_addr;
		size_t sg_bytes;

		if (offset >= sg->length) {
			offset -= sg->length;
			sg = sg_next(sg);
			continue;
		}
		sg_bytes = min(remaining, sg->length - offset);

		/*
		 * The scatterlist item may be bigger than PAGE_SIZE,
		 * but we are limited to mapping PAGE_SIZE at a time.
		 */
		off = offset + sg->offset;
		sg_bytes = min(sg_bytes, (size_t)
			       (PAGE_SIZE - (off & ~PAGE_MASK)));
		page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT),
					KM_SOFTIRQ0);
		if (!page_addr)
			break;		/* XXX panic? */

		if (fr_flags(fp) & FCPHF_CRC_UNCHECKED)
			crc = crc32(crc, buf, sg_bytes);
		memcpy((char *)page_addr + (off & ~PAGE_MASK), buf,
		       sg_bytes);

		kunmap_atomic(page_addr, KM_SOFTIRQ0);
		buf += sg_bytes;
		offset += sg_bytes;
		remaining -= sg_bytes;
		copy_len += sg_bytes;
	}

	if (fr_flags(fp) & FCPHF_CRC_UNCHECKED) {
		buf = fc_frame_payload_get(fp, 0);
		if (len % 4) {
			crc = crc32(crc, buf + len, 4 - (len % 4));
			len += 4 - (len % 4);
		}

		if (~crc != le32_to_cpu(fr_crc(fp))) {
crc_err:
			stats = lp->dev_stats[smp_processor_id()];
			stats->ErrorFrames++;
			if (stats->InvalidCRCCount++ < 5)
				FC_DBG("CRC error on data frame\n");
			/*
			 * Assume the frame is total garbage.
			 * We may have copied it over the good part
			 * of the buffer.
			 * If so, we need to retry the entire operation.
			 * Otherwise, ignore it.
			 */
			if (fsp->state & FC_SRB_DISCONTIG)
				fc_fcp_retry_cmd(fsp);
			return;
		}
	}

	if (fsp->xfer_contig_end == start_offset)
		fsp->xfer_contig_end += copy_len;
	fsp->xfer_len += copy_len;

	/*
	 * In the very rare event that this data arrived after the response
	 * and completes the transfer, call the completion handler.
	 */
	if (unlikely(fsp->state & FC_SRB_RCV_STATUS) &&
	    fsp->xfer_len == fsp->data_len - fsp->scsi_resid)
		fc_fcp_complete_locked(fsp);
}

/**
 * fc_fcp_send_data() -  Send SCSI data to target.
 * @fsp: ptr to fc_fcp_pkt
 * @sp: ptr to this sequence
 * @offset: starting offset for this data request
 * @seq_blen: the burst length for this data request
 *
 * Called after receiving a Transfer Ready data descriptor.
 * if LLD is capable of seq offload then send down seq_blen
 * size of data in single frame, otherwise send multiple FC
 * frames of max FC frame payload supported by target port.
 *
 * Returns : 0 for success.
 */
static int fc_fcp_send_data(struct fc_fcp_pkt *fsp, struct fc_seq *seq,
			    size_t offset, size_t seq_blen)
{
	struct fc_exch *ep;
	struct scsi_cmnd *sc;
	struct scatterlist *sg;
	struct fc_frame *fp = NULL;
	struct fc_lport *lp = fsp->lp;
	size_t remaining;
	size_t t_blen;
	size_t tlen;
	size_t sg_bytes;
	size_t frame_offset, fh_parm_offset;
	int error;
	void *data = NULL;
	void *page_addr;
	int using_sg = lp->sg_supp;
	u32 f_ctl;

	WARN_ON(seq_blen <= 0);
	if (unlikely(offset + seq_blen > fsp->data_len)) {
		/* this should never happen */
		FC_DEBUG_FCP("xfer-ready past end. seq_blen %zx offset %zx\n",
			     seq_blen, offset);
		fc_fcp_send_abort(fsp);
		return 0;
	} else if (offset != fsp->xfer_len) {
		/* Out of Order Data Request - no problem, but unexpected. */
		FC_DEBUG_FCP("xfer-ready non-contiguous. "
			     "seq_blen %zx offset %zx\n", seq_blen, offset);
	}

	/*
	 * if LLD is capable of seq_offload then set transport
	 * burst length (t_blen) to seq_blen, otherwise set t_blen
	 * to max FC frame payload previously set in fsp->max_payload.
	 */
	t_blen = lp->seq_offload ? seq_blen : fsp->max_payload;
	WARN_ON(t_blen < FC_MIN_MAX_PAYLOAD);
	if (t_blen > 512)
		t_blen &= ~(512 - 1);	/* round down to block size */
	WARN_ON(t_blen < FC_MIN_MAX_PAYLOAD);	/* won't go below 256 */
	sc = fsp->cmd;

	remaining = seq_blen;
	fh_parm_offset = frame_offset = offset;
	tlen = 0;
	seq = lp->tt.seq_start_next(seq);
	f_ctl = FC_FC_REL_OFF;
	WARN_ON(!seq);

	/*
	 * If a get_page()/put_page() will fail, don't use sg lists
	 * in the fc_frame structure.
	 *
	 * The put_page() may be long after the I/O has completed
	 * in the case of FCoE, since the network driver does it
	 * via free_skb().  See the test in free_pages_check().
	 *
	 * Test this case with 'dd </dev/zero >/dev/st0 bs=64k'.
	 */
	if (using_sg) {
		for (sg = scsi_sglist(sc); sg; sg = sg_next(sg)) {
			if (page_count(sg_page(sg)) == 0 ||
			    (sg_page(sg)->flags & (1 << PG_lru |
						   1 << PG_private |
						   1 << PG_locked |
						   1 << PG_active |
						   1 << PG_slab |
						   1 << PG_swapcache |
						   1 << PG_writeback |
						   1 << PG_reserved |
						   1 << PG_buddy))) {
				using_sg = 0;
				break;
			}
		}
	}
	sg = scsi_sglist(sc);

	while (remaining > 0 && sg) {
		if (offset >= sg->length) {
			offset -= sg->length;
			sg = sg_next(sg);
			continue;
		}
		if (!fp) {
			tlen = min(t_blen, remaining);

			/*
			 * TODO.  Temporary workaround.	 fc_seq_send() can't
			 * handle odd lengths in non-linear skbs.
			 * This will be the final fragment only.
			 */
			if (tlen % 4)
				using_sg = 0;
			if (using_sg) {
				fp = _fc_frame_alloc(lp, 0);
				if (!fp)
					return -ENOMEM;
			} else {
				fp = fc_frame_alloc(lp, tlen);
				if (!fp)
					return -ENOMEM;

				data = (void *)(fr_hdr(fp)) +
					sizeof(struct fc_frame_header);
			}
			fh_parm_offset = frame_offset;
			fr_max_payload(fp) = fsp->max_payload;
		}
		sg_bytes = min(tlen, sg->length - offset);
		if (using_sg) {
			WARN_ON(skb_shinfo(fp_skb(fp))->nr_frags >
				FC_FRAME_SG_LEN);
			get_page(sg_page(sg));
			skb_fill_page_desc(fp_skb(fp),
					   skb_shinfo(fp_skb(fp))->nr_frags,
					   sg_page(sg), sg->offset + offset,
					   sg_bytes);
			fp_skb(fp)->data_len += sg_bytes;
			fr_len(fp) += sg_bytes;
			fp_skb(fp)->truesize += PAGE_SIZE;
		} else {
			size_t off = offset + sg->offset;

			/*
			 * The scatterlist item may be bigger than PAGE_SIZE,
			 * but we must not cross pages inside the kmap.
			 */
			sg_bytes = min(sg_bytes, (size_t) (PAGE_SIZE -
							   (off & ~PAGE_MASK)));
			page_addr = kmap_atomic(sg_page(sg) +
						(off >> PAGE_SHIFT),
						KM_SOFTIRQ0);
			memcpy(data, (char *)page_addr + (off & ~PAGE_MASK),
			       sg_bytes);
			kunmap_atomic(page_addr, KM_SOFTIRQ0);
			data += sg_bytes;
		}
		offset += sg_bytes;
		frame_offset += sg_bytes;
		tlen -= sg_bytes;
		remaining -= sg_bytes;

		if (tlen)
			continue;

		/*
		 * Send sequence with transfer sequence initiative in case
		 * this is last FCP frame of the sequence.
		 */
		if (remaining == 0)
			f_ctl |= FC_FC_SEQ_INIT | FC_FC_END_SEQ;

		ep = fc_seq_exch(seq);
		fc_fill_fc_hdr(fp, FC_RCTL_DD_SOL_DATA, ep->did, ep->sid,
			       FC_TYPE_FCP, f_ctl, fh_parm_offset);

		/*
		 * send fragment using for a sequence.
		 */
		error = lp->tt.seq_send(lp, seq, fp);
		if (error) {
			WARN_ON(1);		/* send error should be rare */
			fc_fcp_retry_cmd(fsp);
			return 0;
		}
		fp = NULL;
	}
	fsp->xfer_len += seq_blen;	/* premature count? */
	return 0;
}

static void fc_fcp_abts_resp(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
{
	int ba_done = 1;
	struct fc_ba_rjt *brp;
	struct fc_frame_header *fh;

	fh = fc_frame_header_get(fp);
	switch (fh->fh_r_ctl) {
	case FC_RCTL_BA_ACC:
		break;
	case FC_RCTL_BA_RJT:
		brp = fc_frame_payload_get(fp, sizeof(*brp));
		if (brp && brp->br_reason == FC_BA_RJT_LOG_ERR)
			break;
		/* fall thru */
	default:
		/*
		 * we will let the command timeout
		 * and scsi-ml recover in this case,
		 * therefore cleared the ba_done flag.
		 */
		ba_done = 0;
	}

	if (ba_done) {
		fsp->state |= FC_SRB_ABORTED;
		fsp->state &= ~FC_SRB_ABORT_PENDING;

		if (fsp->wait_for_comp)
			complete(&fsp->tm_done);
		else
			fc_fcp_complete_locked(fsp);
	}
}

/**
 * fc_fcp_reduce_can_queue() - drop can_queue
 * @lp: lport to drop queueing for
 *
 * If we are getting memory allocation failures, then we may
 * be trying to execute too many commands. We let the running
 * commands complete or timeout, then try again with a reduced
 * can_queue. Eventually we will hit the point where we run
 * on all reserved structs.
 */
static void fc_fcp_reduce_can_queue(struct fc_lport *lp)
{
	struct fc_fcp_internal *si = fc_get_scsi_internal(lp);
	unsigned long flags;
	int can_queue;

	spin_lock_irqsave(lp->host->host_lock, flags);
	if (si->throttled)
		goto done;
	si->throttled = 1;

	can_queue = lp->host->can_queue;
	can_queue >>= 1;
	if (!can_queue)
		can_queue = 1;
	lp->host->can_queue = can_queue;
	shost_printk(KERN_ERR, lp->host, "Could not allocate frame.\n"
		     "Reducing can_queue to %d.\n", can_queue);
done:
	spin_unlock_irqrestore(lp->host->host_lock, flags);
}

/**
 * fc_fcp_recv() - Reveive FCP frames
 * @seq: The sequence the frame is on
 * @fp: The FC frame
 * @arg: The related FCP packet
 *
 * Return   : None
 * Context  : called from Soft IRQ context
 *	      can not called holding list lock
 */
static void fc_fcp_recv(struct fc_seq *seq, struct fc_frame *fp, void *arg)
{
	struct fc_fcp_pkt *fsp = (struct fc_fcp_pkt *)arg;
	struct fc_lport *lp;
	struct fc_frame_header *fh;
	struct fcp_txrdy *dd;
	u8 r_ctl;
	int rc = 0;

	if (IS_ERR(fp))
		goto errout;

	fh = fc_frame_header_get(fp);
	r_ctl = fh->fh_r_ctl;
	lp = fsp->lp;

	if (!(lp->state & LPORT_ST_READY))
		goto out;
	if (fc_fcp_lock_pkt(fsp))
		goto out;
	fsp->last_pkt_time = jiffies;

	if (fh->fh_type == FC_TYPE_BLS) {
		fc_fcp_abts_resp(fsp, fp);
		goto unlock;
	}

	if (fsp->state & (FC_SRB_ABORTED | FC_SRB_ABORT_PENDING))
		goto unlock;

	if (r_ctl == FC_RCTL_DD_DATA_DESC) {
		/*
		 * received XFER RDY from the target
		 * need to send data to the target
		 */
		WARN_ON(fr_flags(fp) & FCPHF_CRC_UNCHECKED);
		dd = fc_frame_payload_get(fp, sizeof(*dd));
		WARN_ON(!dd);

		rc = fc_fcp_send_data(fsp, seq,
				      (size_t) ntohl(dd->ft_data_ro),
				      (size_t) ntohl(dd->ft_burst_len));
		if (!rc)
			seq->rec_data = fsp->xfer_len;
		else if (rc == -ENOMEM)
			fsp->state |= FC_SRB_NOMEM;
	} else if (r_ctl == FC_RCTL_DD_SOL_DATA) {
		/*
		 * received a DATA frame
		 * next we will copy the data to the system buffer
		 */
		WARN_ON(fr_len(fp) < sizeof(*fh));	/* len may be 0 */
		fc_fcp_recv_data(fsp, fp);
		seq->rec_data = fsp->xfer_contig_end;
	} else if (r_ctl == FC_RCTL_DD_CMD_STATUS) {
		WARN_ON(fr_flags(fp) & FCPHF_CRC_UNCHECKED);

		fc_fcp_resp(fsp, fp);
	} else {
		FC_DBG("unexpected frame.  r_ctl %x\n", r_ctl);
	}
unlock:
	fc_fcp_unlock_pkt(fsp);
out:
	fc_frame_free(fp);
errout:
	if (IS_ERR(fp))
		fc_fcp_error(fsp, fp);
	else if (rc == -ENOMEM)
		fc_fcp_reduce_can_queue(lp);
}

static void fc_fcp_resp(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
{
	struct fc_frame_header *fh;
	struct fcp_resp *fc_rp;
	struct fcp_resp_ext *rp_ex;
	struct fcp_resp_rsp_info *fc_rp_info;
	u32 plen;
	u32 expected_len;
	u32 respl = 0;
	u32 snsl = 0;
	u8 flags = 0;

	plen = fr_len(fp);
	fh = (struct fc_frame_header *)fr_hdr(fp);
	if (unlikely(plen < sizeof(*fh) + sizeof(*fc_rp)))
		goto len_err;
	plen -= sizeof(*fh);
	fc_rp = (struct fcp_resp *)(fh + 1);
	fsp->cdb_status = fc_rp->fr_status;
	flags = fc_rp->fr_flags;
	fsp->scsi_comp_flags = flags;
	expected_len = fsp->data_len;

	if (unlikely((flags & ~FCP_CONF_REQ) || fc_rp->fr_status)) {
		rp_ex = (void *)(fc_rp + 1);
		if (flags & (FCP_RSP_LEN_VAL | FCP_SNS_LEN_VAL)) {
			if (plen < sizeof(*fc_rp) + sizeof(*rp_ex))
				goto len_err;
			fc_rp_info = (struct fcp_resp_rsp_info *)(rp_ex + 1);
			if (flags & FCP_RSP_LEN_VAL) {
				respl = ntohl(rp_ex->fr_rsp_len);
				if (respl != sizeof(*fc_rp_info))
					goto len_err;
				if (fsp->wait_for_comp) {
					/* Abuse cdb_status for rsp code */
					fsp->cdb_status = fc_rp_info->rsp_code;
					complete(&fsp->tm_done);
					/*
					 * tmfs will not have any scsi cmd so
					 * exit here
					 */
					return;
				} else
					goto err;
			}
			if (flags & FCP_SNS_LEN_VAL) {
				snsl = ntohl(rp_ex->fr_sns_len);
				if (snsl > SCSI_SENSE_BUFFERSIZE)
					snsl = SCSI_SENSE_BUFFERSIZE;
				memcpy(fsp->cmd->sense_buffer,
				       (char *)fc_rp_info + respl, snsl);
			}
		}
		if (flags & (FCP_RESID_UNDER | FCP_RESID_OVER)) {
			if (plen < sizeof(*fc_rp) + sizeof(rp_ex->fr_resid))
				goto len_err;
			if (flags & FCP_RESID_UNDER) {
				fsp->scsi_resid = ntohl(rp_ex->fr_resid);
				/*
				 * The cmnd->underflow is the minimum number of
				 * bytes that must be transfered for this
				 * command.  Provided a sense condition is not
				 * present, make sure the actual amount
				 * transferred is at least the underflow value
				 * or fail.
				 */
				if (!(flags & FCP_SNS_LEN_VAL) &&
				    (fc_rp->fr_status == 0) &&
				    (scsi_bufflen(fsp->cmd) -
				     fsp->scsi_resid) < fsp->cmd->underflow)
					goto err;
				expected_len -= fsp->scsi_resid;
			} else {
				fsp->status_code = FC_ERROR;
			}
		}
	}
	fsp->state |= FC_SRB_RCV_STATUS;

	/*
	 * Check for missing or extra data frames.
	 */
	if (unlikely(fsp->xfer_len != expected_len)) {
		if (fsp->xfer_len < expected_len) {
			/*
			 * Some data may be queued locally,
			 * Wait a at least one jiffy to see if it is delivered.
			 * If this expires without data, we may do SRR.
			 */
			fc_fcp_timer_set(fsp, 2);
			return;
		}
		fsp->status_code = FC_DATA_OVRRUN;
		FC_DBG("tgt %6x xfer len %zx greater than expected len %x. "
		       "data len %x\n",
		       fsp->rport->port_id,
		       fsp->xfer_len, expected_len, fsp->data_len);
	}
	fc_fcp_complete_locked(fsp);
	return;

len_err:
	FC_DBG("short FCP response. flags 0x%x len %u respl %u snsl %u\n",
	       flags, fr_len(fp), respl, snsl);
err:
	fsp->status_code = FC_ERROR;
	fc_fcp_complete_locked(fsp);
}

/**
 * fc_fcp_complete_locked() - complete processing of a fcp packet
 * @fsp:	fcp packet
 *
 * This function may sleep if a timer is pending. The packet lock must be
 * held, and the host lock must not be held.
 */
static void fc_fcp_complete_locked(struct fc_fcp_pkt *fsp)
{
	struct fc_lport *lp = fsp->lp;
	struct fc_seq *seq;
	struct fc_exch *ep;
	u32 f_ctl;

	if (fsp->state & FC_SRB_ABORT_PENDING)
		return;

	if (fsp->state & FC_SRB_ABORTED) {
		if (!fsp->status_code)
			fsp->status_code = FC_CMD_ABORTED;
	} else {
		/*
		 * Test for transport underrun, independent of response
		 * underrun status.
		 */
		if (fsp->xfer_len < fsp->data_len && !fsp->io_status &&
		    (!(fsp->scsi_comp_flags & FCP_RESID_UNDER) ||
		     fsp->xfer_len < fsp->data_len - fsp->scsi_resid)) {
			fsp->status_code = FC_DATA_UNDRUN;
			fsp->io_status = SUGGEST_RETRY << 24;
		}
	}

	seq = fsp->seq_ptr;
	if (seq) {
		fsp->seq_ptr = NULL;
		if (unlikely(fsp->scsi_comp_flags & FCP_CONF_REQ)) {
			struct fc_frame *conf_frame;
			struct fc_seq *csp;

			csp = lp->tt.seq_start_next(seq);
			conf_frame = fc_frame_alloc(fsp->lp, 0);
			if (conf_frame) {
				f_ctl = FC_FC_SEQ_INIT;
				f_ctl |= FC_FC_LAST_SEQ | FC_FC_END_SEQ;
				ep = fc_seq_exch(seq);
				fc_fill_fc_hdr(conf_frame, FC_RCTL_DD_SOL_CTL,
					       ep->did, ep->sid,
					       FC_TYPE_FCP, f_ctl, 0);
				lp->tt.seq_send(lp, csp, conf_frame);
			}
		}
		lp->tt.exch_done(seq);
	}
	fc_io_compl(fsp);
}

static void fc_fcp_cleanup_cmd(struct fc_fcp_pkt *fsp, int error)
{
	struct fc_lport *lp = fsp->lp;

	if (fsp->seq_ptr) {
		lp->tt.exch_done(fsp->seq_ptr);
		fsp->seq_ptr = NULL;
	}
	fsp->status_code = error;
}

/**
 * fc_fcp_cleanup_each_cmd() - Cleanup active commads
 * @lp:		logical port
 * @id:		target id
 * @lun:	lun
 * @error:	fsp status code
 *
 * If lun or id is -1, they are ignored.
 */
static void fc_fcp_cleanup_each_cmd(struct fc_lport *lp, unsigned int id,
				    unsigned int lun, int error)
{
	struct fc_fcp_internal *si = fc_get_scsi_internal(lp);
	struct fc_fcp_pkt *fsp;
	struct scsi_cmnd *sc_cmd;
	unsigned long flags;

	spin_lock_irqsave(lp->host->host_lock, flags);
restart:
	list_for_each_entry(fsp, &si->scsi_pkt_queue, list) {
		sc_cmd = fsp->cmd;
		if (id != -1 && scmd_id(sc_cmd) != id)
			continue;

		if (lun != -1 && sc_cmd->device->lun != lun)
			continue;

		fc_fcp_pkt_hold(fsp);
		spin_unlock_irqrestore(lp->host->host_lock, flags);

		if (!fc_fcp_lock_pkt(fsp)) {
			fc_fcp_cleanup_cmd(fsp, error);
			fc_io_compl(fsp);
			fc_fcp_unlock_pkt(fsp);
		}

		fc_fcp_pkt_release(fsp);
		spin_lock_irqsave(lp->host->host_lock, flags);
		/*
		 * while we dropped the lock multiple pkts could
		 * have been released, so we have to start over.
		 */
		goto restart;
	}
	spin_unlock_irqrestore(lp->host->host_lock, flags);
}

static void fc_fcp_abort_io(struct fc_lport *lp)
{
	fc_fcp_cleanup_each_cmd(lp, -1, -1, FC_HRD_ERROR);
}

/**
 * fc_fcp_pkt_send() - send a fcp packet to the lower level.
 * @lp:		fc lport
 * @fsp:	fc packet.
 *
 * This is called by upper layer protocol.
 * Return   : zero for success and -1 for failure
 * Context  : called from queuecommand which can be called from process
 *	      or scsi soft irq.
 * Locks    : called with the host lock and irqs disabled.
 */
static int fc_fcp_pkt_send(struct fc_lport *lp, struct fc_fcp_pkt *fsp)
{
	struct fc_fcp_internal *si = fc_get_scsi_internal(lp);
	int rc;

	fsp->cmd->SCp.ptr = (char *)fsp;
	fsp->cdb_cmd.fc_dl = htonl(fsp->data_len);
	fsp->cdb_cmd.fc_flags = fsp->req_flags & ~FCP_CFL_LEN_MASK;

	int_to_scsilun(fsp->cmd->device->lun,
		       (struct scsi_lun *)fsp->cdb_cmd.fc_lun);
	memcpy(fsp->cdb_cmd.fc_cdb, fsp->cmd->cmnd, fsp->cmd->cmd_len);
	list_add_tail(&fsp->list, &si->scsi_pkt_queue);

	spin_unlock_irq(lp->host->host_lock);
	rc = lp->tt.fcp_cmd_send(lp, fsp, fc_fcp_recv);
	spin_lock_irq(lp->host->host_lock);
	if (rc)
		list_del(&fsp->list);

	return rc;
}

static int fc_fcp_cmd_send(struct fc_lport *lp, struct fc_fcp_pkt *fsp,
			   void (*resp)(struct fc_seq *,
					struct fc_frame *fp,
					void *arg))
{
	struct fc_frame *fp;
	struct fc_seq *seq;
	struct fc_rport *rport;
	struct fc_rport_libfc_priv *rp;
	const size_t len = sizeof(fsp->cdb_cmd);
	int rc = 0;

	if (fc_fcp_lock_pkt(fsp))
		return 0;

	fp = fc_frame_alloc(lp, sizeof(fsp->cdb_cmd));
	if (!fp) {
		rc = -1;
		goto unlock;
	}

	memcpy(fc_frame_payload_get(fp, len), &fsp->cdb_cmd, len);
	fr_cmd(fp) = fsp->cmd;
	rport = fsp->rport;
	fsp->max_payload = rport->maxframe_size;
	rp = rport->dd_data;

	fc_fill_fc_hdr(fp, FC_RCTL_DD_UNSOL_CMD, rport->port_id,
		       fc_host_port_id(rp->local_port->host), FC_TYPE_FCP,
		       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);

	seq = lp->tt.exch_seq_send(lp, fp, resp, fc_fcp_pkt_destroy, fsp, 0);
	if (!seq) {
		fc_frame_free(fp);
		rc = -1;
		goto unlock;
	}
	fsp->last_pkt_time = jiffies;
	fsp->seq_ptr = seq;
	fc_fcp_pkt_hold(fsp);	/* hold for fc_fcp_pkt_destroy */

	setup_timer(&fsp->timer, fc_fcp_timeout, (unsigned long)fsp);
	fc_fcp_timer_set(fsp,
			 (fsp->tgt_flags & FC_RP_FLAGS_REC_SUPPORTED) ?
			 FC_SCSI_REC_TOV : FC_SCSI_ER_TIMEOUT);
unlock:
	fc_fcp_unlock_pkt(fsp);
	return rc;
}

/*
 * transport error handler
 */
static void fc_fcp_error(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
{
	int error = PTR_ERR(fp);

	if (fc_fcp_lock_pkt(fsp))
		return;

	switch (error) {
	case -FC_EX_CLOSED:
		fc_fcp_retry_cmd(fsp);
		goto unlock;
	default:
		FC_DBG("unknown error %ld\n", PTR_ERR(fp));
	}
	/*
	 * clear abort pending, because the lower layer
	 * decided to force completion.
	 */
	fsp->state &= ~FC_SRB_ABORT_PENDING;
	fsp->status_code = FC_CMD_PLOGO;
	fc_fcp_complete_locked(fsp);
unlock:
	fc_fcp_unlock_pkt(fsp);
}

/*
 * Scsi abort handler- calls to send an abort
 * and then wait for abort completion
 */
static int fc_fcp_pkt_abort(struct fc_lport *lp, struct fc_fcp_pkt *fsp)
{
	int rc = FAILED;

	if (fc_fcp_send_abort(fsp))
		return FAILED;

	init_completion(&fsp->tm_done);
	fsp->wait_for_comp = 1;

	spin_unlock_bh(&fsp->scsi_pkt_lock);
	rc = wait_for_completion_timeout(&fsp->tm_done, FC_SCSI_TM_TOV);
	spin_lock_bh(&fsp->scsi_pkt_lock);
	fsp->wait_for_comp = 0;

	if (!rc) {
		FC_DBG("target abort cmd  failed\n");
		rc = FAILED;
	} else if (fsp->state & FC_SRB_ABORTED) {
		FC_DBG("target abort cmd  passed\n");
		rc = SUCCESS;
		fc_fcp_complete_locked(fsp);
	}

	return rc;
}

/*
 * Retry LUN reset after resource allocation failed.
 */
static void fc_lun_reset_send(unsigned long data)
{
	struct fc_fcp_pkt *fsp = (struct fc_fcp_pkt *)data;
	struct fc_lport *lp = fsp->lp;
	if (lp->tt.fcp_cmd_send(lp, fsp, fc_tm_done)) {
		if (fsp->recov_retry++ >= FC_MAX_RECOV_RETRY)
			return;
		if (fc_fcp_lock_pkt(fsp))
			return;
		setup_timer(&fsp->timer, fc_lun_reset_send, (unsigned long)fsp);
		fc_fcp_timer_set(fsp, FC_SCSI_REC_TOV);
		fc_fcp_unlock_pkt(fsp);
	}
}

/*
 * Scsi device reset handler- send a LUN RESET to the device
 * and wait for reset reply
 */
static int fc_lun_reset(struct fc_lport *lp, struct fc_fcp_pkt *fsp,
			unsigned int id, unsigned int lun)
{
	int rc;

	fsp->cdb_cmd.fc_dl = htonl(fsp->data_len);
	fsp->cdb_cmd.fc_tm_flags = FCP_TMF_LUN_RESET;
	int_to_scsilun(lun, (struct scsi_lun *)fsp->cdb_cmd.fc_lun);

	fsp->wait_for_comp = 1;
	init_completion(&fsp->tm_done);

	fc_lun_reset_send((unsigned long)fsp);

	/*
	 * wait for completion of reset
	 * after that make sure all commands are terminated
	 */
	rc = wait_for_completion_timeout(&fsp->tm_done, FC_SCSI_TM_TOV);

	spin_lock_bh(&fsp->scsi_pkt_lock);
	fsp->state |= FC_SRB_COMPL;
	spin_unlock_bh(&fsp->scsi_pkt_lock);

	del_timer_sync(&fsp->timer);

	spin_lock_bh(&fsp->scsi_pkt_lock);
	if (fsp->seq_ptr) {
		lp->tt.exch_done(fsp->seq_ptr);
		fsp->seq_ptr = NULL;
	}
	fsp->wait_for_comp = 0;
	spin_unlock_bh(&fsp->scsi_pkt_lock);

	if (!rc) {
		FC_DBG("lun reset failed\n");
		return FAILED;
	}

	/* cdb_status holds the tmf's rsp code */
	if (fsp->cdb_status != FCP_TMF_CMPL)
		return FAILED;

	FC_DBG("lun reset to lun %u completed\n", lun);
	fc_fcp_cleanup_each_cmd(lp, id, lun, FC_CMD_ABORTED);
	return SUCCESS;
}

/*
 * Task Managment response handler
 */
static void fc_tm_done(struct fc_seq *seq, struct fc_frame *fp, void *arg)
{
	struct fc_fcp_pkt *fsp = arg;
	struct fc_frame_header *fh;

	if (IS_ERR(fp)) {
		/*
		 * If there is an error just let it timeout or wait
		 * for TMF to be aborted if it timedout.
		 *
		 * scsi-eh will escalate for when either happens.
		 */
		return;
	}

	if (fc_fcp_lock_pkt(fsp))
		return;

	/*
	 * raced with eh timeout handler.
	 */
	if (!fsp->seq_ptr || !fsp->wait_for_comp) {
		spin_unlock_bh(&fsp->scsi_pkt_lock);
		return;
	}

	fh = fc_frame_header_get(fp);
	if (fh->fh_type != FC_TYPE_BLS)
		fc_fcp_resp(fsp, fp);
	fsp->seq_ptr = NULL;
	fsp->lp->tt.exch_done(seq);
	fc_frame_free(fp);
	fc_fcp_unlock_pkt(fsp);
}

static void fc_fcp_cleanup(struct fc_lport *lp)
{
	fc_fcp_cleanup_each_cmd(lp, -1, -1, FC_ERROR);
}

/*
 * fc_fcp_timeout: called by OS timer function.
 *
 * The timer has been inactivated and must be reactivated if desired
 * using fc_fcp_timer_set().
 *
 * Algorithm:
 *
 * If REC is supported, just issue it, and return.  The REC exchange will
 * complete or time out, and recovery can continue at that point.
 *
 * Otherwise, if the response has been received without all the data,
 * it has been ER_TIMEOUT since the response was received.
 *
 * If the response has not been received,
 * we see if data was received recently.  If it has been, we continue waiting,
 * otherwise, we abort the command.
 */
static void fc_fcp_timeout(unsigned long data)
{
	struct fc_fcp_pkt *fsp = (struct fc_fcp_pkt *)data;
	struct fc_rport *rport = fsp->rport;
	struct fc_rport_libfc_priv *rp = rport->dd_data;

	if (fc_fcp_lock_pkt(fsp))
		return;

	if (fsp->cdb_cmd.fc_tm_flags)
		goto unlock;

	fsp->state |= FC_SRB_FCP_PROCESSING_TMO;

	if (rp->flags & FC_RP_FLAGS_REC_SUPPORTED)
		fc_fcp_rec(fsp);
	else if (time_after_eq(fsp->last_pkt_time + (FC_SCSI_ER_TIMEOUT / 2),
			       jiffies))
		fc_fcp_timer_set(fsp, FC_SCSI_ER_TIMEOUT);
	else if (fsp->state & FC_SRB_RCV_STATUS)
		fc_fcp_complete_locked(fsp);
	else
		fc_timeout_error(fsp);
	fsp->state &= ~FC_SRB_FCP_PROCESSING_TMO;
unlock:
	fc_fcp_unlock_pkt(fsp);
}

/*
 * Send a REC ELS request
 */
static void fc_fcp_rec(struct fc_fcp_pkt *fsp)
{
	struct fc_lport *lp;
	struct fc_frame *fp;
	struct fc_rport *rport;
	struct fc_rport_libfc_priv *rp;

	lp = fsp->lp;
	rport = fsp->rport;
	rp = rport->dd_data;
	if (!fsp->seq_ptr || rp->rp_state != RPORT_ST_READY) {
		fsp->status_code = FC_HRD_ERROR;
		fsp->io_status = SUGGEST_RETRY << 24;
		fc_fcp_complete_locked(fsp);
		return;
	}
	fp = fc_frame_alloc(lp, sizeof(struct fc_els_rec));
	if (!fp)
		goto retry;

	fr_seq(fp) = fsp->seq_ptr;
	fc_fill_fc_hdr(fp, FC_RCTL_ELS_REQ, rport->port_id,
		       fc_host_port_id(rp->local_port->host), FC_TYPE_ELS,
		       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
	if (lp->tt.elsct_send(lp, rport, fp, ELS_REC, fc_fcp_rec_resp,
			      fsp, jiffies_to_msecs(FC_SCSI_REC_TOV))) {
		fc_fcp_pkt_hold(fsp);		/* hold while REC outstanding */
		return;
	}
	fc_frame_free(fp);
retry:
	if (fsp->recov_retry++ < FC_MAX_RECOV_RETRY)
		fc_fcp_timer_set(fsp, FC_SCSI_REC_TOV);
	else
		fc_timeout_error(fsp);
}

/*
 * Receive handler for REC ELS frame
 * if it is a reject then let the scsi layer to handle
 * the timeout. if it is a LS_ACC then if the io was not completed
 * then set the timeout and return otherwise complete the exchange
 * and tell the scsi layer to restart the I/O.
 */
static void fc_fcp_rec_resp(struct fc_seq *seq, struct fc_frame *fp, void *arg)
{
	struct fc_fcp_pkt *fsp = (struct fc_fcp_pkt *)arg;
	struct fc_els_rec_acc *recp;
	struct fc_els_ls_rjt *rjt;
	u32 e_stat;
	u8 opcode;
	u32 offset;
	enum dma_data_direction data_dir;
	enum fc_rctl r_ctl;
	struct fc_rport_libfc_priv *rp;

	if (IS_ERR(fp)) {
		fc_fcp_rec_error(fsp, fp);
		return;
	}

	if (fc_fcp_lock_pkt(fsp))
		goto out;

	fsp->recov_retry = 0;
	opcode = fc_frame_payload_op(fp);
	if (opcode == ELS_LS_RJT) {
		rjt = fc_frame_payload_get(fp, sizeof(*rjt));
		switch (rjt->er_reason) {
		default:
			FC_DEBUG_FCP("device %x unexpected REC reject "
				     "reason %d expl %d\n",
				     fsp->rport->port_id, rjt->er_reason,
				     rjt->er_explan);
			/* fall through */
		case ELS_RJT_UNSUP:
			FC_DEBUG_FCP("device does not support REC\n");
			rp = fsp->rport->dd_data;
			/*
			 * if we do not spport RECs or got some bogus
			 * reason then resetup timer so we check for
			 * making progress.
			 */
			rp->flags &= ~FC_RP_FLAGS_REC_SUPPORTED;
			fc_fcp_timer_set(fsp, FC_SCSI_ER_TIMEOUT);
			break;
		case ELS_RJT_LOGIC:
		case ELS_RJT_UNAB:
			/*
			 * If no data transfer, the command frame got dropped
			 * so we just retry.  If data was transferred, we
			 * lost the response but the target has no record,
			 * so we abort and retry.
			 */
			if (rjt->er_explan == ELS_EXPL_OXID_RXID &&
			    fsp->xfer_len == 0) {
				fc_fcp_retry_cmd(fsp);
				break;
			}
			fc_timeout_error(fsp);
			break;
		}
	} else if (opcode == ELS_LS_ACC) {
		if (fsp->state & FC_SRB_ABORTED)
			goto unlock_out;

		data_dir = fsp->cmd->sc_data_direction;
		recp = fc_frame_payload_get(fp, sizeof(*recp));
		offset = ntohl(recp->reca_fc4value);
		e_stat = ntohl(recp->reca_e_stat);

		if (e_stat & ESB_ST_COMPLETE) {

			/*
			 * The exchange is complete.
			 *
			 * For output, we must've lost the response.
			 * For input, all data must've been sent.
			 * We lost may have lost the response
			 * (and a confirmation was requested) and maybe
			 * some data.
			 *
			 * If all data received, send SRR
			 * asking for response.	 If partial data received,
			 * or gaps, SRR requests data at start of gap.
			 * Recovery via SRR relies on in-order-delivery.
			 */
			if (data_dir == DMA_TO_DEVICE) {
				r_ctl = FC_RCTL_DD_CMD_STATUS;
			} else if (fsp->xfer_contig_end == offset) {
				r_ctl = FC_RCTL_DD_CMD_STATUS;
			} else {
				offset = fsp->xfer_contig_end;
				r_ctl = FC_RCTL_DD_SOL_DATA;
			}
			fc_fcp_srr(fsp, r_ctl, offset);
		} else if (e_stat & ESB_ST_SEQ_INIT) {

			/*
			 * The remote port has the initiative, so just
			 * keep waiting for it to complete.
			 */
			fc_fcp_timer_set(fsp, FC_SCSI_REC_TOV);
		} else {

			/*
			 * The exchange is incomplete, we have seq. initiative.
			 * Lost response with requested confirmation,
			 * lost confirmation, lost transfer ready or
			 * lost write data.
			 *
			 * For output, if not all data was received, ask
			 * for transfer ready to be repeated.
			 *
			 * If we received or sent all the data, send SRR to
			 * request response.
			 *
			 * If we lost a response, we may have lost some read
			 * data as well.
			 */
			r_ctl = FC_RCTL_DD_SOL_DATA;
			if (data_dir == DMA_TO_DEVICE) {
				r_ctl = FC_RCTL_DD_CMD_STATUS;
				if (offset < fsp->data_len)
					r_ctl = FC_RCTL_DD_DATA_DESC;
			} else if (offset == fsp->xfer_contig_end) {
				r_ctl = FC_RCTL_DD_CMD_STATUS;
			} else if (fsp->xfer_contig_end < offset) {
				offset = fsp->xfer_contig_end;
			}
			fc_fcp_srr(fsp, r_ctl, offset);
		}
	}
unlock_out:
	fc_fcp_unlock_pkt(fsp);
out:
	fc_fcp_pkt_release(fsp);	/* drop hold for outstanding REC */
	fc_frame_free(fp);
}

/*
 * Handle error response or timeout for REC exchange.
 */
static void fc_fcp_rec_error(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
{
	int error = PTR_ERR(fp);

	if (fc_fcp_lock_pkt(fsp))
		goto out;

	switch (error) {
	case -FC_EX_CLOSED:
		fc_fcp_retry_cmd(fsp);
		break;

	default:
		FC_DBG("REC %p fid %x error unexpected error %d\n",
		       fsp, fsp->rport->port_id, error);
		fsp->status_code = FC_CMD_PLOGO;
		/* fall through */

	case -FC_EX_TIMEOUT:
		/*
		 * Assume REC or LS_ACC was lost.
		 * The exchange manager will have aborted REC, so retry.
		 */
		FC_DBG("REC fid %x error error %d retry %d/%d\n",
		       fsp->rport->port_id, error, fsp->recov_retry,
		       FC_MAX_RECOV_RETRY);
		if (fsp->recov_retry++ < FC_MAX_RECOV_RETRY)
			fc_fcp_rec(fsp);
		else
			fc_timeout_error(fsp);
		break;
	}
	fc_fcp_unlock_pkt(fsp);
out:
	fc_fcp_pkt_release(fsp);	/* drop hold for outstanding REC */
}

/*
 * Time out error routine:
 * abort's the I/O close the exchange and
 * send completion notification to scsi layer
 */
static void fc_timeout_error(struct fc_fcp_pkt *fsp)
{
	fsp->status_code = FC_CMD_TIME_OUT;
	fsp->cdb_status = 0;
	fsp->io_status = 0;
	/*
	 * if this fails then we let the scsi command timer fire and
	 * scsi-ml escalate.
	 */
	fc_fcp_send_abort(fsp);
}

/*
 * Sequence retransmission request.
 * This is called after receiving status but insufficient data, or
 * when expecting status but the request has timed out.
 */
static void fc_fcp_srr(struct fc_fcp_pkt *fsp, enum fc_rctl r_ctl, u32 offset)
{
	struct fc_lport *lp = fsp->lp;
	struct fc_rport *rport;
	struct fc_rport_libfc_priv *rp;
	struct fc_exch *ep = fc_seq_exch(fsp->seq_ptr);
	struct fc_seq *seq;
	struct fcp_srr *srr;
	struct fc_frame *fp;
	u8 cdb_op;

	rport = fsp->rport;
	rp = rport->dd_data;
	cdb_op = fsp->cdb_cmd.fc_cdb[0];

	if (!(rp->flags & FC_RP_FLAGS_RETRY) || rp->rp_state != RPORT_ST_READY)
		goto retry;			/* shouldn't happen */
	fp = fc_frame_alloc(lp, sizeof(*srr));
	if (!fp)
		goto retry;

	srr = fc_frame_payload_get(fp, sizeof(*srr));
	memset(srr, 0, sizeof(*srr));
	srr->srr_op = ELS_SRR;
	srr->srr_ox_id = htons(ep->oxid);
	srr->srr_rx_id = htons(ep->rxid);
	srr->srr_r_ctl = r_ctl;
	srr->srr_rel_off = htonl(offset);

	fc_fill_fc_hdr(fp, FC_RCTL_ELS4_REQ, rport->port_id,
		       fc_host_port_id(rp->local_port->host), FC_TYPE_FCP,
		       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);

	seq = lp->tt.exch_seq_send(lp, fp, fc_fcp_srr_resp, NULL,
				   fsp, jiffies_to_msecs(FC_SCSI_REC_TOV));
	if (!seq) {
		fc_frame_free(fp);
		goto retry;
	}
	fsp->recov_seq = seq;
	fsp->xfer_len = offset;
	fsp->xfer_contig_end = offset;
	fsp->state &= ~FC_SRB_RCV_STATUS;
	fc_fcp_pkt_hold(fsp);		/* hold for outstanding SRR */
	return;
retry:
	fc_fcp_retry_cmd(fsp);
}

/*
 * Handle response from SRR.
 */
static void fc_fcp_srr_resp(struct fc_seq *seq, struct fc_frame *fp, void *arg)
{
	struct fc_fcp_pkt *fsp = arg;
	struct fc_frame_header *fh;

	if (IS_ERR(fp)) {
		fc_fcp_srr_error(fsp, fp);
		return;
	}

	if (fc_fcp_lock_pkt(fsp))
		goto out;

	fh = fc_frame_header_get(fp);
	/*
	 * BUG? fc_fcp_srr_error calls exch_done which would release
	 * the ep. But if fc_fcp_srr_error had got -FC_EX_TIMEOUT,
	 * then fc_exch_timeout would be sending an abort. The exch_done
	 * call by fc_fcp_srr_error would prevent fc_exch.c from seeing
	 * an abort response though.
	 */
	if (fh->fh_type == FC_TYPE_BLS) {
		fc_fcp_unlock_pkt(fsp);
		return;
	}

	fsp->recov_seq = NULL;
	switch (fc_frame_payload_op(fp)) {
	case ELS_LS_ACC:
		fsp->recov_retry = 0;
		fc_fcp_timer_set(fsp, FC_SCSI_REC_TOV);
		break;
	case ELS_LS_RJT:
	default:
		fc_timeout_error(fsp);
		break;
	}
	fc_fcp_unlock_pkt(fsp);
	fsp->lp->tt.exch_done(seq);
out:
	fc_frame_free(fp);
	fc_fcp_pkt_release(fsp);	/* drop hold for outstanding SRR */
}

static void fc_fcp_srr_error(struct fc_fcp_pkt *fsp, struct fc_frame *fp)
{
	if (fc_fcp_lock_pkt(fsp))
		goto out;
	fsp->lp->tt.exch_done(fsp->recov_seq);
	fsp->recov_seq = NULL;
	switch (PTR_ERR(fp)) {
	case -FC_EX_TIMEOUT:
		if (fsp->recov_retry++ < FC_MAX_RECOV_RETRY)
			fc_fcp_rec(fsp);
		else
			fc_timeout_error(fsp);
		break;
	case -FC_EX_CLOSED:			/* e.g., link failure */
		/* fall through */
	default:
		fc_fcp_retry_cmd(fsp);
		break;
	}
	fc_fcp_unlock_pkt(fsp);
out:
	fc_fcp_pkt_release(fsp);	/* drop hold for outstanding SRR */
}

static inline int fc_fcp_lport_queue_ready(struct fc_lport *lp)
{
	/* lock ? */
	return (lp->state == LPORT_ST_READY) && lp->link_up && !lp->qfull;
}

/**
 * fc_queuecommand - The queuecommand function of the scsi template
 * @cmd:	struct scsi_cmnd to be executed
 * @done:	Callback function to be called when cmd is completed
 *
 * this is the i/o strategy routine, called by the scsi layer
 * this routine is called with holding the host_lock.
 */
int fc_queuecommand(struct scsi_cmnd *sc_cmd, void (*done)(struct scsi_cmnd *))
{
	struct fc_lport *lp;
	struct fc_rport *rport = starget_to_rport(scsi_target(sc_cmd->device));
	struct fc_fcp_pkt *fsp;
	struct fc_rport_libfc_priv *rp;
	int rval;
	int rc = 0;
	struct fcoe_dev_stats *stats;

	lp = shost_priv(sc_cmd->device->host);

	rval = fc_remote_port_chkready(rport);
	if (rval) {
		sc_cmd->result = rval;
		done(sc_cmd);
		goto out;
	}

	if (!*(struct fc_remote_port **)rport->dd_data) {
		/*
		 * rport is transitioning from blocked/deleted to
		 * online
		 */
		sc_cmd->result = DID_IMM_RETRY << 16;
		done(sc_cmd);
		goto out;
	}

	rp = rport->dd_data;

	if (!fc_fcp_lport_queue_ready(lp)) {
		rc = SCSI_MLQUEUE_HOST_BUSY;
		goto out;
	}

	fsp = fc_fcp_pkt_alloc(lp, GFP_ATOMIC);
	if (fsp == NULL) {
		rc = SCSI_MLQUEUE_HOST_BUSY;
		goto out;
	}

	/*
	 * build the libfc request pkt
	 */
	fsp->cmd = sc_cmd;	/* save the cmd */
	fsp->lp = lp;		/* save the softc ptr */
	fsp->rport = rport;	/* set the remote port ptr */
	sc_cmd->scsi_done = done;

	/*
	 * set up the transfer length
	 */
	fsp->data_len = scsi_bufflen(sc_cmd);
	fsp->xfer_len = 0;

	/*
	 * setup the data direction
	 */
	stats = lp->dev_stats[smp_processor_id()];
	if (sc_cmd->sc_data_direction == DMA_FROM_DEVICE) {
		fsp->req_flags = FC_SRB_READ;
		stats->InputRequests++;
		stats->InputMegabytes = fsp->data_len;
	} else if (sc_cmd->sc_data_direction == DMA_TO_DEVICE) {
		fsp->req_flags = FC_SRB_WRITE;
		stats->OutputRequests++;
		stats->OutputMegabytes = fsp->data_len;
	} else {
		fsp->req_flags = 0;
		stats->ControlRequests++;
	}

	fsp->tgt_flags = rp->flags;

	init_timer(&fsp->timer);
	fsp->timer.data = (unsigned long)fsp;

	/*
	 * send it to the lower layer
	 * if we get -1 return then put the request in the pending
	 * queue.
	 */
	rval = fc_fcp_pkt_send(lp, fsp);
	if (rval != 0) {
		fsp->state = FC_SRB_FREE;
		fc_fcp_pkt_release(fsp);
		rc = SCSI_MLQUEUE_HOST_BUSY;
	}
out:
	return rc;
}
EXPORT_SYMBOL(fc_queuecommand);

/**
 * fc_io_compl() -  Handle responses for completed commands
 * @fsp:	scsi packet
 *
 * Translates a error to a Linux SCSI error.
 *
 * The fcp packet lock must be held when calling.
 */
static void fc_io_compl(struct fc_fcp_pkt *fsp)
{
	struct fc_fcp_internal *si;
	struct scsi_cmnd *sc_cmd;
	struct fc_lport *lp;
	unsigned long flags;

	fsp->state |= FC_SRB_COMPL;
	if (!(fsp->state & FC_SRB_FCP_PROCESSING_TMO)) {
		spin_unlock_bh(&fsp->scsi_pkt_lock);
		del_timer_sync(&fsp->timer);
		spin_lock_bh(&fsp->scsi_pkt_lock);
	}

	lp = fsp->lp;
	si = fc_get_scsi_internal(lp);
	spin_lock_irqsave(lp->host->host_lock, flags);
	if (!fsp->cmd) {
		spin_unlock_irqrestore(lp->host->host_lock, flags);
		return;
	}

	/*
	 * if a command timed out while we had to try and throttle IO
	 * and it is now getting cleaned up, then we are about to
	 * try again so clear the throttled flag incase we get more
	 * time outs.
	 */
	if (si->throttled && fsp->state & FC_SRB_NOMEM)
		si->throttled = 0;

	sc_cmd = fsp->cmd;
	fsp->cmd = NULL;

	if (!sc_cmd->SCp.ptr) {
		spin_unlock_irqrestore(lp->host->host_lock, flags);
		return;
	}

	CMD_SCSI_STATUS(sc_cmd) = fsp->cdb_status;
	switch (fsp->status_code) {
	case FC_COMPLETE:
		if (fsp->cdb_status == 0) {
			/*
			 * good I/O status
			 */
			sc_cmd->result = DID_OK << 16;
			if (fsp->scsi_resid)
				CMD_RESID_LEN(sc_cmd) = fsp->scsi_resid;
		} else if (fsp->cdb_status == QUEUE_FULL) {
			struct scsi_device *tmp_sdev;
			struct scsi_device *sdev = sc_cmd->device;

			shost_for_each_device(tmp_sdev, sdev->host) {
				if (tmp_sdev->id != sdev->id)
					continue;

				if (tmp_sdev->queue_depth > 1) {
					scsi_track_queue_full(tmp_sdev,
							      tmp_sdev->
							      queue_depth - 1);
				}
			}
			sc_cmd->result = (DID_OK << 16) | fsp->cdb_status;
		} else {
			/*
			 * transport level I/O was ok but scsi
			 * has non zero status
			 */
			sc_cmd->result = (DID_OK << 16) | fsp->cdb_status;
		}
		break;
	case FC_ERROR:
		sc_cmd->result = DID_ERROR << 16;
		break;
	case FC_DATA_UNDRUN:
		if ((fsp->cdb_status == 0) && !(fsp->req_flags & FC_SRB_READ)) {
			/*
			 * scsi status is good but transport level
			 * underrun.
			 */
			sc_cmd->result = DID_OK << 16;
		} else {
			/*
			 * scsi got underrun, this is an error
			 */
			CMD_RESID_LEN(sc_cmd) = fsp->scsi_resid;
			sc_cmd->result = (DID_ERROR << 16) | fsp->cdb_status;
		}
		break;
	case FC_DATA_OVRRUN:
		/*
		 * overrun is an error
		 */
		sc_cmd->result = (DID_ERROR << 16) | fsp->cdb_status;
		break;
	case FC_CMD_ABORTED:
		sc_cmd->result = (DID_ABORT << 16) | fsp->io_status;
		break;
	case FC_CMD_TIME_OUT:
		sc_cmd->result = (DID_BUS_BUSY << 16) | fsp->io_status;
		break;
	case FC_CMD_RESET:
		sc_cmd->result = (DID_RESET << 16);
		break;
	case FC_HRD_ERROR:
		sc_cmd->result = (DID_NO_CONNECT << 16);
		break;
	default:
		sc_cmd->result = (DID_ERROR << 16);
		break;
	}

	list_del(&fsp->list);
	sc_cmd->SCp.ptr = NULL;
	sc_cmd->scsi_done(sc_cmd);
	spin_unlock_irqrestore(lp->host->host_lock, flags);

	/* release ref from initial allocation in queue command */
	fc_fcp_pkt_release(fsp);
}

/**
 * fc_fcp_complete() - complete processing of a fcp packet
 * @fsp:	fcp packet
 *
 * This function may sleep if a fsp timer is pending.
 * The host lock must not be held by caller.
 */
void fc_fcp_complete(struct fc_fcp_pkt *fsp)
{
	if (fc_fcp_lock_pkt(fsp))
		return;

	fc_fcp_complete_locked(fsp);
	fc_fcp_unlock_pkt(fsp);
}
EXPORT_SYMBOL(fc_fcp_complete);

/**
 * fc_eh_abort() - Abort a command
 * @sc_cmd:	scsi command to abort
 *
 * From scsi host template.
 * send ABTS to the target device  and wait for the response
 * sc_cmd is the pointer to the command to be aborted.
 */
int fc_eh_abort(struct scsi_cmnd *sc_cmd)
{
	struct fc_fcp_pkt *fsp;
	struct fc_lport *lp;
	int rc = FAILED;
	unsigned long flags;

	lp = shost_priv(sc_cmd->device->host);
	if (lp->state != LPORT_ST_READY)
		return rc;
	else if (!lp->link_up)
		return rc;

	spin_lock_irqsave(lp->host->host_lock, flags);
	fsp = CMD_SP(sc_cmd);
	if (!fsp) {
		/* command completed while scsi eh was setting up */
		spin_unlock_irqrestore(lp->host->host_lock, flags);
		return SUCCESS;
	}
	/* grab a ref so the fsp and sc_cmd cannot be relased from under us */
	fc_fcp_pkt_hold(fsp);
	spin_unlock_irqrestore(lp->host->host_lock, flags);

	if (fc_fcp_lock_pkt(fsp)) {
		/* completed while we were waiting for timer to be deleted */
		rc = SUCCESS;
		goto release_pkt;
	}

	rc = fc_fcp_pkt_abort(lp, fsp);
	fc_fcp_unlock_pkt(fsp);

release_pkt:
	fc_fcp_pkt_release(fsp);
	return rc;
}
EXPORT_SYMBOL(fc_eh_abort);

/**
 * fc_eh_device_reset() Reset a single LUN
 * @sc_cmd:	scsi command
 *
 * Set from scsi host template to send tm cmd to the target and wait for the
 * response.
 */
int fc_eh_device_reset(struct scsi_cmnd *sc_cmd)
{
	struct fc_lport *lp;
	struct fc_fcp_pkt *fsp;
	struct fc_rport *rport = starget_to_rport(scsi_target(sc_cmd->device));
	int rc = FAILED;
	struct fc_rport_libfc_priv *rp;
	int rval;

	rval = fc_remote_port_chkready(rport);
	if (rval)
		goto out;

	rp = rport->dd_data;
	lp = shost_priv(sc_cmd->device->host);

	if (lp->state != LPORT_ST_READY)
		return rc;

	fsp = fc_fcp_pkt_alloc(lp, GFP_NOIO);
	if (fsp == NULL) {
		FC_DBG("could not allocate scsi_pkt\n");
		sc_cmd->result = DID_NO_CONNECT << 16;
		goto out;
	}

	/*
	 * Build the libfc request pkt. Do not set the scsi cmnd, because
	 * the sc passed in is not setup for execution like when sent
	 * through the queuecommand callout.
	 */
	fsp->lp = lp;		/* save the softc ptr */
	fsp->rport = rport;	/* set the remote port ptr */

	/*
	 * flush outstanding commands
	 */
	rc = fc_lun_reset(lp, fsp, scmd_id(sc_cmd), sc_cmd->device->lun);
	fsp->state = FC_SRB_FREE;
	fc_fcp_pkt_release(fsp);

out:
	return rc;
}
EXPORT_SYMBOL(fc_eh_device_reset);

/**
 * fc_eh_host_reset() - The reset function will reset the ports on the host.
 * @sc_cmd:	scsi command
 */
int fc_eh_host_reset(struct scsi_cmnd *sc_cmd)
{
	struct Scsi_Host *shost = sc_cmd->device->host;
	struct fc_lport *lp = shost_priv(shost);
	unsigned long wait_tmo;

	lp->tt.lport_reset(lp);
	wait_tmo = jiffies + FC_HOST_RESET_TIMEOUT;
	while (!fc_fcp_lport_queue_ready(lp) && time_before(jiffies, wait_tmo))
		msleep(1000);

	if (fc_fcp_lport_queue_ready(lp)) {
		shost_printk(KERN_INFO, shost, "Host reset succeeded.\n");
		return SUCCESS;
	} else {
		shost_printk(KERN_INFO, shost, "Host reset failed. "
			     "lport not ready.\n");
		return FAILED;
	}
}
EXPORT_SYMBOL(fc_eh_host_reset);

/**
 * fc_slave_alloc() - configure queue depth
 * @sdev:	scsi device
 *
 * Configures queue depth based on host's cmd_per_len. If not set
 * then we use the libfc default.
 */
int fc_slave_alloc(struct scsi_device *sdev)
{
	struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
	int queue_depth;

	if (!rport || fc_remote_port_chkready(rport))
		return -ENXIO;

	if (sdev->tagged_supported) {
		if (sdev->host->hostt->cmd_per_lun)
			queue_depth = sdev->host->hostt->cmd_per_lun;
		else
			queue_depth = FC_FCP_DFLT_QUEUE_DEPTH;
		scsi_activate_tcq(sdev, queue_depth);
	}
	return 0;
}
EXPORT_SYMBOL(fc_slave_alloc);

int fc_change_queue_depth(struct scsi_device *sdev, int qdepth)
{
	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), qdepth);
	return sdev->queue_depth;
}
EXPORT_SYMBOL(fc_change_queue_depth);

int fc_change_queue_type(struct scsi_device *sdev, int tag_type)
{
	if (sdev->tagged_supported) {
		scsi_set_tag_type(sdev, tag_type);
		if (tag_type)
			scsi_activate_tcq(sdev, sdev->queue_depth);
		else
			scsi_deactivate_tcq(sdev, sdev->queue_depth);
	} else
		tag_type = 0;

	return tag_type;
}
EXPORT_SYMBOL(fc_change_queue_type);

void fc_fcp_destroy(struct fc_lport *lp)
{
	struct fc_fcp_internal *si = fc_get_scsi_internal(lp);

	if (!list_empty(&si->scsi_pkt_queue))
		printk(KERN_ERR "Leaked scsi packets.\n");

	mempool_destroy(si->scsi_pkt_pool);
	kfree(si);
	lp->scsi_priv = NULL;
}
EXPORT_SYMBOL(fc_fcp_destroy);

int fc_fcp_init(struct fc_lport *lp)
{
	int rc;
	struct fc_fcp_internal *si;

	if (!lp->tt.fcp_cmd_send)
		lp->tt.fcp_cmd_send = fc_fcp_cmd_send;

	if (!lp->tt.fcp_cleanup)
		lp->tt.fcp_cleanup = fc_fcp_cleanup;

	if (!lp->tt.fcp_abort_io)
		lp->tt.fcp_abort_io = fc_fcp_abort_io;

	si = kzalloc(sizeof(struct fc_fcp_internal), GFP_KERNEL);
	if (!si)
		return -ENOMEM;
	lp->scsi_priv = si;
	INIT_LIST_HEAD(&si->scsi_pkt_queue);

	si->scsi_pkt_pool = mempool_create_slab_pool(2, scsi_pkt_cachep);
	if (!si->scsi_pkt_pool) {
		rc = -ENOMEM;
		goto free_internal;
	}
	return 0;

free_internal:
	kfree(si);
	return rc;
}
EXPORT_SYMBOL(fc_fcp_init);

static int __init libfc_init(void)
{
	int rc;

	scsi_pkt_cachep = kmem_cache_create("libfc_fcp_pkt",
					    sizeof(struct fc_fcp_pkt),
					    0, SLAB_HWCACHE_ALIGN, NULL);
	if (scsi_pkt_cachep == NULL) {
		FC_DBG("Unable to allocate SRB cache...module load failed!");
		return -ENOMEM;
	}

	rc = fc_setup_exch_mgr();
	if (rc)
		goto destroy_pkt_cache;

	rc = fc_setup_rport();
	if (rc)
		goto destroy_em;

	return rc;
destroy_em:
	fc_destroy_exch_mgr();
destroy_pkt_cache:
	kmem_cache_destroy(scsi_pkt_cachep);
	return rc;
}

static void __exit libfc_exit(void)
{
	kmem_cache_destroy(scsi_pkt_cachep);
	fc_destroy_exch_mgr();
	fc_destroy_rport();
}

module_init(libfc_init);
module_exit(libfc_exit);
OpenPOWER on IntegriCloud