summaryrefslogtreecommitdiff
path: root/drivers/block/nvme.c
blob: c1dc4d86c22122f4b34abd35880cfcbb0896215d (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
/*
 * NVM Express device driver
 * Copyright (c) 2011, Intel Corporation.
 *
 * 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.
 */

#include <linux/nvme.h>
#include <linux/bio.h>
#include <linux/bitops.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kdev_t.h>
#include <linux/kthread.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
#include <linux/poison.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/version.h>

#define NVME_Q_DEPTH 1024
#define SQ_SIZE(depth)		(depth * sizeof(struct nvme_command))
#define CQ_SIZE(depth)		(depth * sizeof(struct nvme_completion))
#define NVME_MINORS 64
#define NVME_IO_TIMEOUT	(5 * HZ)
#define ADMIN_TIMEOUT	(60 * HZ)

static int nvme_major;
module_param(nvme_major, int, 0);

static int use_threaded_interrupts;
module_param(use_threaded_interrupts, int, 0);

static DEFINE_SPINLOCK(dev_list_lock);
static LIST_HEAD(dev_list);
static struct task_struct *nvme_thread;

/*
 * Represents an NVM Express device.  Each nvme_dev is a PCI function.
 */
struct nvme_dev {
	struct list_head node;
	struct nvme_queue **queues;
	u32 __iomem *dbs;
	struct pci_dev *pci_dev;
	struct dma_pool *prp_page_pool;
	struct dma_pool *prp_small_pool;
	int instance;
	int queue_count;
	int db_stride;
	u32 ctrl_config;
	struct msix_entry *entry;
	struct nvme_bar __iomem *bar;
	struct list_head namespaces;
	char serial[20];
	char model[40];
	char firmware_rev[8];
};

/*
 * An NVM Express namespace is equivalent to a SCSI LUN
 */
struct nvme_ns {
	struct list_head list;

	struct nvme_dev *dev;
	struct request_queue *queue;
	struct gendisk *disk;

	int ns_id;
	int lba_shift;
};

/*
 * An NVM Express queue.  Each device has at least two (one for admin
 * commands and one for I/O commands).
 */
struct nvme_queue {
	struct device *q_dmadev;
	struct nvme_dev *dev;
	spinlock_t q_lock;
	struct nvme_command *sq_cmds;
	volatile struct nvme_completion *cqes;
	dma_addr_t sq_dma_addr;
	dma_addr_t cq_dma_addr;
	wait_queue_head_t sq_full;
	wait_queue_t sq_cong_wait;
	struct bio_list sq_cong;
	u32 __iomem *q_db;
	u16 q_depth;
	u16 cq_vector;
	u16 sq_head;
	u16 sq_tail;
	u16 cq_head;
	u16 cq_phase;
	unsigned long cmdid_data[];
};

/*
 * Check we didin't inadvertently grow the command struct
 */
static inline void _nvme_check_size(void)
{
	BUILD_BUG_ON(sizeof(struct nvme_rw_command) != 64);
	BUILD_BUG_ON(sizeof(struct nvme_create_cq) != 64);
	BUILD_BUG_ON(sizeof(struct nvme_create_sq) != 64);
	BUILD_BUG_ON(sizeof(struct nvme_delete_queue) != 64);
	BUILD_BUG_ON(sizeof(struct nvme_features) != 64);
	BUILD_BUG_ON(sizeof(struct nvme_command) != 64);
	BUILD_BUG_ON(sizeof(struct nvme_id_ctrl) != 4096);
	BUILD_BUG_ON(sizeof(struct nvme_id_ns) != 4096);
	BUILD_BUG_ON(sizeof(struct nvme_lba_range_type) != 64);
}

typedef void (*nvme_completion_fn)(struct nvme_dev *, void *,
						struct nvme_completion *);

struct nvme_cmd_info {
	nvme_completion_fn fn;
	void *ctx;
	unsigned long timeout;
};

static struct nvme_cmd_info *nvme_cmd_info(struct nvme_queue *nvmeq)
{
	return (void *)&nvmeq->cmdid_data[BITS_TO_LONGS(nvmeq->q_depth)];
}

/**
 * alloc_cmdid() - Allocate a Command ID
 * @nvmeq: The queue that will be used for this command
 * @ctx: A pointer that will be passed to the handler
 * @handler: The function to call on completion
 *
 * Allocate a Command ID for a queue.  The data passed in will
 * be passed to the completion handler.  This is implemented by using
 * the bottom two bits of the ctx pointer to store the handler ID.
 * Passing in a pointer that's not 4-byte aligned will cause a BUG.
 * We can change this if it becomes a problem.
 *
 * May be called with local interrupts disabled and the q_lock held,
 * or with interrupts enabled and no locks held.
 */
static int alloc_cmdid(struct nvme_queue *nvmeq, void *ctx,
				nvme_completion_fn handler, unsigned timeout)
{
	int depth = nvmeq->q_depth - 1;
	struct nvme_cmd_info *info = nvme_cmd_info(nvmeq);
	int cmdid;

	do {
		cmdid = find_first_zero_bit(nvmeq->cmdid_data, depth);
		if (cmdid >= depth)
			return -EBUSY;
	} while (test_and_set_bit(cmdid, nvmeq->cmdid_data));

	info[cmdid].fn = handler;
	info[cmdid].ctx = ctx;
	info[cmdid].timeout = jiffies + timeout;
	return cmdid;
}

static int alloc_cmdid_killable(struct nvme_queue *nvmeq, void *ctx,
				nvme_completion_fn handler, unsigned timeout)
{
	int cmdid;
	wait_event_killable(nvmeq->sq_full,
		(cmdid = alloc_cmdid(nvmeq, ctx, handler, timeout)) >= 0);
	return (cmdid < 0) ? -EINTR : cmdid;
}

/* Special values must be less than 0x1000 */
#define CMD_CTX_BASE		((void *)POISON_POINTER_DELTA)
#define CMD_CTX_CANCELLED	(0x30C + CMD_CTX_BASE)
#define CMD_CTX_COMPLETED	(0x310 + CMD_CTX_BASE)
#define CMD_CTX_INVALID		(0x314 + CMD_CTX_BASE)
#define CMD_CTX_FLUSH		(0x318 + CMD_CTX_BASE)

static void special_completion(struct nvme_dev *dev, void *ctx,
						struct nvme_completion *cqe)
{
	if (ctx == CMD_CTX_CANCELLED)
		return;
	if (ctx == CMD_CTX_FLUSH)
		return;
	if (ctx == CMD_CTX_COMPLETED) {
		dev_warn(&dev->pci_dev->dev,
				"completed id %d twice on queue %d\n",
				cqe->command_id, le16_to_cpup(&cqe->sq_id));
		return;
	}
	if (ctx == CMD_CTX_INVALID) {
		dev_warn(&dev->pci_dev->dev,
				"invalid id %d completed on queue %d\n",
				cqe->command_id, le16_to_cpup(&cqe->sq_id));
		return;
	}

	dev_warn(&dev->pci_dev->dev, "Unknown special completion %p\n", ctx);
}

/*
 * Called with local interrupts disabled and the q_lock held.  May not sleep.
 */
static void *free_cmdid(struct nvme_queue *nvmeq, int cmdid,
						nvme_completion_fn *fn)
{
	void *ctx;
	struct nvme_cmd_info *info = nvme_cmd_info(nvmeq);

	if (cmdid >= nvmeq->q_depth) {
		*fn = special_completion;
		return CMD_CTX_INVALID;
	}
	*fn = info[cmdid].fn;
	ctx = info[cmdid].ctx;
	info[cmdid].fn = special_completion;
	info[cmdid].ctx = CMD_CTX_COMPLETED;
	clear_bit(cmdid, nvmeq->cmdid_data);
	wake_up(&nvmeq->sq_full);
	return ctx;
}

static void *cancel_cmdid(struct nvme_queue *nvmeq, int cmdid,
						nvme_completion_fn *fn)
{
	void *ctx;
	struct nvme_cmd_info *info = nvme_cmd_info(nvmeq);
	if (fn)
		*fn = info[cmdid].fn;
	ctx = info[cmdid].ctx;
	info[cmdid].fn = special_completion;
	info[cmdid].ctx = CMD_CTX_CANCELLED;
	return ctx;
}

static struct nvme_queue *get_nvmeq(struct nvme_dev *dev)
{
	return dev->queues[get_cpu() + 1];
}

static void put_nvmeq(struct nvme_queue *nvmeq)
{
	put_cpu();
}

/**
 * nvme_submit_cmd() - Copy a command into a queue and ring the doorbell
 * @nvmeq: The queue to use
 * @cmd: The command to send
 *
 * Safe to use from interrupt context
 */
static int nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
{
	unsigned long flags;
	u16 tail;
	spin_lock_irqsave(&nvmeq->q_lock, flags);
	tail = nvmeq->sq_tail;
	memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
	if (++tail == nvmeq->q_depth)
		tail = 0;
	writel(tail, nvmeq->q_db);
	nvmeq->sq_tail = tail;
	spin_unlock_irqrestore(&nvmeq->q_lock, flags);

	return 0;
}

/*
 * The nvme_iod describes the data in an I/O, including the list of PRP
 * entries.  You can't see it in this data structure because C doesn't let
 * me express that.  Use nvme_alloc_iod to ensure there's enough space
 * allocated to store the PRP list.
 */
struct nvme_iod {
	void *private;		/* For the use of the submitter of the I/O */
	int npages;		/* In the PRP list. 0 means small pool in use */
	int offset;		/* Of PRP list */
	int nents;		/* Used in scatterlist */
	int length;		/* Of data, in bytes */
	dma_addr_t first_dma;
	struct scatterlist sg[0];
};

static __le64 **iod_list(struct nvme_iod *iod)
{
	return ((void *)iod) + iod->offset;
}

/*
 * Will slightly overestimate the number of pages needed.  This is OK
 * as it only leads to a small amount of wasted memory for the lifetime of
 * the I/O.
 */
static int nvme_npages(unsigned size)
{
	unsigned nprps = DIV_ROUND_UP(size + PAGE_SIZE, PAGE_SIZE);
	return DIV_ROUND_UP(8 * nprps, PAGE_SIZE - 8);
}

static struct nvme_iod *
nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp)
{
	struct nvme_iod *iod = kmalloc(sizeof(struct nvme_iod) +
				sizeof(__le64 *) * nvme_npages(nbytes) +
				sizeof(struct scatterlist) * nseg, gfp);

	if (iod) {
		iod->offset = offsetof(struct nvme_iod, sg[nseg]);
		iod->npages = -1;
		iod->length = nbytes;
	}

	return iod;
}

static void nvme_free_iod(struct nvme_dev *dev, struct nvme_iod *iod)
{
	const int last_prp = PAGE_SIZE / 8 - 1;
	int i;
	__le64 **list = iod_list(iod);
	dma_addr_t prp_dma = iod->first_dma;

	if (iod->npages == 0)
		dma_pool_free(dev->prp_small_pool, list[0], prp_dma);
	for (i = 0; i < iod->npages; i++) {
		__le64 *prp_list = list[i];
		dma_addr_t next_prp_dma = le64_to_cpu(prp_list[last_prp]);
		dma_pool_free(dev->prp_page_pool, prp_list, prp_dma);
		prp_dma = next_prp_dma;
	}
	kfree(iod);
}

static void requeue_bio(struct nvme_dev *dev, struct bio *bio)
{
	struct nvme_queue *nvmeq = get_nvmeq(dev);
	if (bio_list_empty(&nvmeq->sq_cong))
		add_wait_queue(&nvmeq->sq_full, &nvmeq->sq_cong_wait);
	bio_list_add(&nvmeq->sq_cong, bio);
	put_nvmeq(nvmeq);
	wake_up_process(nvme_thread);
}

static void bio_completion(struct nvme_dev *dev, void *ctx,
						struct nvme_completion *cqe)
{
	struct nvme_iod *iod = ctx;
	struct bio *bio = iod->private;
	u16 status = le16_to_cpup(&cqe->status) >> 1;

	dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
			bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	nvme_free_iod(dev, iod);
	if (status) {
		bio_endio(bio, -EIO);
	} else if (bio->bi_vcnt > bio->bi_idx) {
		requeue_bio(dev, bio);
	} else {
		bio_endio(bio, 0);
	}
}

/* length is in bytes.  gfp flags indicates whether we may sleep. */
static int nvme_setup_prps(struct nvme_dev *dev,
			struct nvme_common_command *cmd, struct nvme_iod *iod,
			int total_len, gfp_t gfp)
{
	struct dma_pool *pool;
	int length = total_len;
	struct scatterlist *sg = iod->sg;
	int dma_len = sg_dma_len(sg);
	u64 dma_addr = sg_dma_address(sg);
	int offset = offset_in_page(dma_addr);
	__le64 *prp_list;
	__le64 **list = iod_list(iod);
	dma_addr_t prp_dma;
	int nprps, i;

	cmd->prp1 = cpu_to_le64(dma_addr);
	length -= (PAGE_SIZE - offset);
	if (length <= 0)
		return total_len;

	dma_len -= (PAGE_SIZE - offset);
	if (dma_len) {
		dma_addr += (PAGE_SIZE - offset);
	} else {
		sg = sg_next(sg);
		dma_addr = sg_dma_address(sg);
		dma_len = sg_dma_len(sg);
	}

	if (length <= PAGE_SIZE) {
		cmd->prp2 = cpu_to_le64(dma_addr);
		return total_len;
	}

	nprps = DIV_ROUND_UP(length, PAGE_SIZE);
	if (nprps <= (256 / 8)) {
		pool = dev->prp_small_pool;
		iod->npages = 0;
	} else {
		pool = dev->prp_page_pool;
		iod->npages = 1;
	}

	prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
	if (!prp_list) {
		cmd->prp2 = cpu_to_le64(dma_addr);
		iod->npages = -1;
		return (total_len - length) + PAGE_SIZE;
	}
	list[0] = prp_list;
	iod->first_dma = prp_dma;
	cmd->prp2 = cpu_to_le64(prp_dma);
	i = 0;
	for (;;) {
		if (i == PAGE_SIZE / 8) {
			__le64 *old_prp_list = prp_list;
			prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
			if (!prp_list)
				return total_len - length;
			list[iod->npages++] = prp_list;
			prp_list[0] = old_prp_list[i - 1];
			old_prp_list[i - 1] = cpu_to_le64(prp_dma);
			i = 1;
		}
		prp_list[i++] = cpu_to_le64(dma_addr);
		dma_len -= PAGE_SIZE;
		dma_addr += PAGE_SIZE;
		length -= PAGE_SIZE;
		if (length <= 0)
			break;
		if (dma_len > 0)
			continue;
		BUG_ON(dma_len < 0);
		sg = sg_next(sg);
		dma_addr = sg_dma_address(sg);
		dma_len = sg_dma_len(sg);
	}

	return total_len;
}

/* NVMe scatterlists require no holes in the virtual address */
#define BIOVEC_NOT_VIRT_MERGEABLE(vec1, vec2)	((vec2)->bv_offset || \
			(((vec1)->bv_offset + (vec1)->bv_len) % PAGE_SIZE))

static int nvme_map_bio(struct device *dev, struct nvme_iod *iod,
		struct bio *bio, enum dma_data_direction dma_dir, int psegs)
{
	struct bio_vec *bvec, *bvprv = NULL;
	struct scatterlist *sg = NULL;
	int i, old_idx, length = 0, nsegs = 0;

	sg_init_table(iod->sg, psegs);
	old_idx = bio->bi_idx;
	bio_for_each_segment(bvec, bio, i) {
		if (bvprv && BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) {
			sg->length += bvec->bv_len;
		} else {
			if (bvprv && BIOVEC_NOT_VIRT_MERGEABLE(bvprv, bvec))
				break;
			sg = sg ? sg + 1 : iod->sg;
			sg_set_page(sg, bvec->bv_page, bvec->bv_len,
							bvec->bv_offset);
			nsegs++;
		}
		length += bvec->bv_len;
		bvprv = bvec;
	}
	bio->bi_idx = i;
	iod->nents = nsegs;
	sg_mark_end(sg);
	if (dma_map_sg(dev, iod->sg, iod->nents, dma_dir) == 0) {
		bio->bi_idx = old_idx;
		return -ENOMEM;
	}
	return length;
}

static int nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
								int cmdid)
{
	struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];

	memset(cmnd, 0, sizeof(*cmnd));
	cmnd->common.opcode = nvme_cmd_flush;
	cmnd->common.command_id = cmdid;
	cmnd->common.nsid = cpu_to_le32(ns->ns_id);

	if (++nvmeq->sq_tail == nvmeq->q_depth)
		nvmeq->sq_tail = 0;
	writel(nvmeq->sq_tail, nvmeq->q_db);

	return 0;
}

static int nvme_submit_flush_data(struct nvme_queue *nvmeq, struct nvme_ns *ns)
{
	int cmdid = alloc_cmdid(nvmeq, (void *)CMD_CTX_FLUSH,
					special_completion, NVME_IO_TIMEOUT);
	if (unlikely(cmdid < 0))
		return cmdid;

	return nvme_submit_flush(nvmeq, ns, cmdid);
}

/*
 * Called with local interrupts disabled and the q_lock held.  May not sleep.
 */
static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
								struct bio *bio)
{
	struct nvme_command *cmnd;
	struct nvme_iod *iod;
	enum dma_data_direction dma_dir;
	int cmdid, length, result = -ENOMEM;
	u16 control;
	u32 dsmgmt;
	int psegs = bio_phys_segments(ns->queue, bio);

	if ((bio->bi_rw & REQ_FLUSH) && psegs) {
		result = nvme_submit_flush_data(nvmeq, ns);
		if (result)
			return result;
	}

	iod = nvme_alloc_iod(psegs, bio->bi_size, GFP_ATOMIC);
	if (!iod)
		goto nomem;
	iod->private = bio;

	result = -EBUSY;
	cmdid = alloc_cmdid(nvmeq, iod, bio_completion, NVME_IO_TIMEOUT);
	if (unlikely(cmdid < 0))
		goto free_iod;

	if ((bio->bi_rw & REQ_FLUSH) && !psegs)
		return nvme_submit_flush(nvmeq, ns, cmdid);

	control = 0;
	if (bio->bi_rw & REQ_FUA)
		control |= NVME_RW_FUA;
	if (bio->bi_rw & (REQ_FAILFAST_DEV | REQ_RAHEAD))
		control |= NVME_RW_LR;

	dsmgmt = 0;
	if (bio->bi_rw & REQ_RAHEAD)
		dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;

	cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];

	memset(cmnd, 0, sizeof(*cmnd));
	if (bio_data_dir(bio)) {
		cmnd->rw.opcode = nvme_cmd_write;
		dma_dir = DMA_TO_DEVICE;
	} else {
		cmnd->rw.opcode = nvme_cmd_read;
		dma_dir = DMA_FROM_DEVICE;
	}

	result = nvme_map_bio(nvmeq->q_dmadev, iod, bio, dma_dir, psegs);
	if (result < 0)
		goto free_iod;
	length = result;

	cmnd->rw.command_id = cmdid;
	cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
	length = nvme_setup_prps(nvmeq->dev, &cmnd->common, iod, length,
								GFP_ATOMIC);
	cmnd->rw.slba = cpu_to_le64(bio->bi_sector >> (ns->lba_shift - 9));
	cmnd->rw.length = cpu_to_le16((length >> ns->lba_shift) - 1);
	cmnd->rw.control = cpu_to_le16(control);
	cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);

	bio->bi_sector += length >> 9;

	if (++nvmeq->sq_tail == nvmeq->q_depth)
		nvmeq->sq_tail = 0;
	writel(nvmeq->sq_tail, nvmeq->q_db);

	return 0;

 free_iod:
	nvme_free_iod(nvmeq->dev, iod);
 nomem:
	return result;
}

static void nvme_make_request(struct request_queue *q, struct bio *bio)
{
	struct nvme_ns *ns = q->queuedata;
	struct nvme_queue *nvmeq = get_nvmeq(ns->dev);
	int result = -EBUSY;

	spin_lock_irq(&nvmeq->q_lock);
	if (bio_list_empty(&nvmeq->sq_cong))
		result = nvme_submit_bio_queue(nvmeq, ns, bio);
	if (unlikely(result)) {
		if (bio_list_empty(&nvmeq->sq_cong))
			add_wait_queue(&nvmeq->sq_full, &nvmeq->sq_cong_wait);
		bio_list_add(&nvmeq->sq_cong, bio);
	}

	spin_unlock_irq(&nvmeq->q_lock);
	put_nvmeq(nvmeq);
}

static irqreturn_t nvme_process_cq(struct nvme_queue *nvmeq)
{
	u16 head, phase;

	head = nvmeq->cq_head;
	phase = nvmeq->cq_phase;

	for (;;) {
		void *ctx;
		nvme_completion_fn fn;
		struct nvme_completion cqe = nvmeq->cqes[head];
		if ((le16_to_cpu(cqe.status) & 1) != phase)
			break;
		nvmeq->sq_head = le16_to_cpu(cqe.sq_head);
		if (++head == nvmeq->q_depth) {
			head = 0;
			phase = !phase;
		}

		ctx = free_cmdid(nvmeq, cqe.command_id, &fn);
		fn(nvmeq->dev, ctx, &cqe);
	}

	/* If the controller ignores the cq head doorbell and continuously
	 * writes to the queue, it is theoretically possible to wrap around
	 * the queue twice and mistakenly return IRQ_NONE.  Linux only
	 * requires that 0.1% of your interrupts are handled, so this isn't
	 * a big problem.
	 */
	if (head == nvmeq->cq_head && phase == nvmeq->cq_phase)
		return IRQ_NONE;

	writel(head, nvmeq->q_db + (1 << nvmeq->dev->db_stride));
	nvmeq->cq_head = head;
	nvmeq->cq_phase = phase;

	return IRQ_HANDLED;
}

static irqreturn_t nvme_irq(int irq, void *data)
{
	irqreturn_t result;
	struct nvme_queue *nvmeq = data;
	spin_lock(&nvmeq->q_lock);
	result = nvme_process_cq(nvmeq);
	spin_unlock(&nvmeq->q_lock);
	return result;
}

static irqreturn_t nvme_irq_check(int irq, void *data)
{
	struct nvme_queue *nvmeq = data;
	struct nvme_completion cqe = nvmeq->cqes[nvmeq->cq_head];
	if ((le16_to_cpu(cqe.status) & 1) != nvmeq->cq_phase)
		return IRQ_NONE;
	return IRQ_WAKE_THREAD;
}

static void nvme_abort_command(struct nvme_queue *nvmeq, int cmdid)
{
	spin_lock_irq(&nvmeq->q_lock);
	cancel_cmdid(nvmeq, cmdid, NULL);
	spin_unlock_irq(&nvmeq->q_lock);
}

struct sync_cmd_info {
	struct task_struct *task;
	u32 result;
	int status;
};

static void sync_completion(struct nvme_dev *dev, void *ctx,
						struct nvme_completion *cqe)
{
	struct sync_cmd_info *cmdinfo = ctx;
	cmdinfo->result = le32_to_cpup(&cqe->result);
	cmdinfo->status = le16_to_cpup(&cqe->status) >> 1;
	wake_up_process(cmdinfo->task);
}

/*
 * Returns 0 on success.  If the result is negative, it's a Linux error code;
 * if the result is positive, it's an NVM Express status code
 */
static int nvme_submit_sync_cmd(struct nvme_queue *nvmeq,
			struct nvme_command *cmd, u32 *result, unsigned timeout)
{
	int cmdid;
	struct sync_cmd_info cmdinfo;

	cmdinfo.task = current;
	cmdinfo.status = -EINTR;

	cmdid = alloc_cmdid_killable(nvmeq, &cmdinfo, sync_completion,
								timeout);
	if (cmdid < 0)
		return cmdid;
	cmd->common.command_id = cmdid;

	set_current_state(TASK_KILLABLE);
	nvme_submit_cmd(nvmeq, cmd);
	schedule();

	if (cmdinfo.status == -EINTR) {
		nvme_abort_command(nvmeq, cmdid);
		return -EINTR;
	}

	if (result)
		*result = cmdinfo.result;

	return cmdinfo.status;
}

static int nvme_submit_admin_cmd(struct nvme_dev *dev, struct nvme_command *cmd,
								u32 *result)
{
	return nvme_submit_sync_cmd(dev->queues[0], cmd, result, ADMIN_TIMEOUT);
}

static int adapter_delete_queue(struct nvme_dev *dev, u8 opcode, u16 id)
{
	int status;
	struct nvme_command c;

	memset(&c, 0, sizeof(c));
	c.delete_queue.opcode = opcode;
	c.delete_queue.qid = cpu_to_le16(id);

	status = nvme_submit_admin_cmd(dev, &c, NULL);
	if (status)
		return -EIO;
	return 0;
}

static int adapter_alloc_cq(struct nvme_dev *dev, u16 qid,
						struct nvme_queue *nvmeq)
{
	int status;
	struct nvme_command c;
	int flags = NVME_QUEUE_PHYS_CONTIG | NVME_CQ_IRQ_ENABLED;

	memset(&c, 0, sizeof(c));
	c.create_cq.opcode = nvme_admin_create_cq;
	c.create_cq.prp1 = cpu_to_le64(nvmeq->cq_dma_addr);
	c.create_cq.cqid = cpu_to_le16(qid);
	c.create_cq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
	c.create_cq.cq_flags = cpu_to_le16(flags);
	c.create_cq.irq_vector = cpu_to_le16(nvmeq->cq_vector);

	status = nvme_submit_admin_cmd(dev, &c, NULL);
	if (status)
		return -EIO;
	return 0;
}

static int adapter_alloc_sq(struct nvme_dev *dev, u16 qid,
						struct nvme_queue *nvmeq)
{
	int status;
	struct nvme_command c;
	int flags = NVME_QUEUE_PHYS_CONTIG | NVME_SQ_PRIO_MEDIUM;

	memset(&c, 0, sizeof(c));
	c.create_sq.opcode = nvme_admin_create_sq;
	c.create_sq.prp1 = cpu_to_le64(nvmeq->sq_dma_addr);
	c.create_sq.sqid = cpu_to_le16(qid);
	c.create_sq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
	c.create_sq.sq_flags = cpu_to_le16(flags);
	c.create_sq.cqid = cpu_to_le16(qid);

	status = nvme_submit_admin_cmd(dev, &c, NULL);
	if (status)
		return -EIO;
	return 0;
}

static int adapter_delete_cq(struct nvme_dev *dev, u16 cqid)
{
	return adapter_delete_queue(dev, nvme_admin_delete_cq, cqid);
}

static int adapter_delete_sq(struct nvme_dev *dev, u16 sqid)
{
	return adapter_delete_queue(dev, nvme_admin_delete_sq, sqid);
}

static int nvme_identify(struct nvme_dev *dev, unsigned nsid, unsigned cns,
							dma_addr_t dma_addr)
{
	struct nvme_command c;

	memset(&c, 0, sizeof(c));
	c.identify.opcode = nvme_admin_identify;
	c.identify.nsid = cpu_to_le32(nsid);
	c.identify.prp1 = cpu_to_le64(dma_addr);
	c.identify.cns = cpu_to_le32(cns);

	return nvme_submit_admin_cmd(dev, &c, NULL);
}

static int nvme_get_features(struct nvme_dev *dev, unsigned fid,
				unsigned dword11, dma_addr_t dma_addr)
{
	struct nvme_command c;

	memset(&c, 0, sizeof(c));
	c.features.opcode = nvme_admin_get_features;
	c.features.prp1 = cpu_to_le64(dma_addr);
	c.features.fid = cpu_to_le32(fid);
	c.features.dword11 = cpu_to_le32(dword11);

	return nvme_submit_admin_cmd(dev, &c, NULL);
}

static int nvme_set_features(struct nvme_dev *dev, unsigned fid,
			unsigned dword11, dma_addr_t dma_addr, u32 *result)
{
	struct nvme_command c;

	memset(&c, 0, sizeof(c));
	c.features.opcode = nvme_admin_set_features;
	c.features.prp1 = cpu_to_le64(dma_addr);
	c.features.fid = cpu_to_le32(fid);
	c.features.dword11 = cpu_to_le32(dword11);

	return nvme_submit_admin_cmd(dev, &c, result);
}

static void nvme_free_queue(struct nvme_dev *dev, int qid)
{
	struct nvme_queue *nvmeq = dev->queues[qid];
	int vector = dev->entry[nvmeq->cq_vector].vector;

	irq_set_affinity_hint(vector, NULL);
	free_irq(vector, nvmeq);

	/* Don't tell the adapter to delete the admin queue */
	if (qid) {
		adapter_delete_sq(dev, qid);
		adapter_delete_cq(dev, qid);
	}

	dma_free_coherent(nvmeq->q_dmadev, CQ_SIZE(nvmeq->q_depth),
				(void *)nvmeq->cqes, nvmeq->cq_dma_addr);
	dma_free_coherent(nvmeq->q_dmadev, SQ_SIZE(nvmeq->q_depth),
					nvmeq->sq_cmds, nvmeq->sq_dma_addr);
	kfree(nvmeq);
}

static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid,
							int depth, int vector)
{
	struct device *dmadev = &dev->pci_dev->dev;
	unsigned extra = (depth / 8) + (depth * sizeof(struct nvme_cmd_info));
	struct nvme_queue *nvmeq = kzalloc(sizeof(*nvmeq) + extra, GFP_KERNEL);
	if (!nvmeq)
		return NULL;

	nvmeq->cqes = dma_alloc_coherent(dmadev, CQ_SIZE(depth),
					&nvmeq->cq_dma_addr, GFP_KERNEL);
	if (!nvmeq->cqes)
		goto free_nvmeq;
	memset((void *)nvmeq->cqes, 0, CQ_SIZE(depth));

	nvmeq->sq_cmds = dma_alloc_coherent(dmadev, SQ_SIZE(depth),
					&nvmeq->sq_dma_addr, GFP_KERNEL);
	if (!nvmeq->sq_cmds)
		goto free_cqdma;

	nvmeq->q_dmadev = dmadev;
	nvmeq->dev = dev;
	spin_lock_init(&nvmeq->q_lock);
	nvmeq->cq_head = 0;
	nvmeq->cq_phase = 1;
	init_waitqueue_head(&nvmeq->sq_full);
	init_waitqueue_entry(&nvmeq->sq_cong_wait, nvme_thread);
	bio_list_init(&nvmeq->sq_cong);
	nvmeq->q_db = &dev->dbs[qid << (dev->db_stride + 1)];
	nvmeq->q_depth = depth;
	nvmeq->cq_vector = vector;

	return nvmeq;

 free_cqdma:
	dma_free_coherent(dmadev, CQ_SIZE(nvmeq->q_depth), (void *)nvmeq->cqes,
							nvmeq->cq_dma_addr);
 free_nvmeq:
	kfree(nvmeq);
	return NULL;
}

static int queue_request_irq(struct nvme_dev *dev, struct nvme_queue *nvmeq,
							const char *name)
{
	if (use_threaded_interrupts)
		return request_threaded_irq(dev->entry[nvmeq->cq_vector].vector,
					nvme_irq_check, nvme_irq,
					IRQF_DISABLED | IRQF_SHARED,
					name, nvmeq);
	return request_irq(dev->entry[nvmeq->cq_vector].vector, nvme_irq,
				IRQF_DISABLED | IRQF_SHARED, name, nvmeq);
}

static __devinit struct nvme_queue *nvme_create_queue(struct nvme_dev *dev,
					int qid, int cq_size, int vector)
{
	int result;
	struct nvme_queue *nvmeq = nvme_alloc_queue(dev, qid, cq_size, vector);

	if (!nvmeq)
		return ERR_PTR(-ENOMEM);

	result = adapter_alloc_cq(dev, qid, nvmeq);
	if (result < 0)
		goto free_nvmeq;

	result = adapter_alloc_sq(dev, qid, nvmeq);
	if (result < 0)
		goto release_cq;

	result = queue_request_irq(dev, nvmeq, "nvme");
	if (result < 0)
		goto release_sq;

	return nvmeq;

 release_sq:
	adapter_delete_sq(dev, qid);
 release_cq:
	adapter_delete_cq(dev, qid);
 free_nvmeq:
	dma_free_coherent(nvmeq->q_dmadev, CQ_SIZE(nvmeq->q_depth),
				(void *)nvmeq->cqes, nvmeq->cq_dma_addr);
	dma_free_coherent(nvmeq->q_dmadev, SQ_SIZE(nvmeq->q_depth),
					nvmeq->sq_cmds, nvmeq->sq_dma_addr);
	kfree(nvmeq);
	return ERR_PTR(result);
}

static int __devinit nvme_configure_admin_queue(struct nvme_dev *dev)
{
	int result;
	u32 aqa;
	u64 cap;
	unsigned long timeout;
	struct nvme_queue *nvmeq;

	dev->dbs = ((void __iomem *)dev->bar) + 4096;

	nvmeq = nvme_alloc_queue(dev, 0, 64, 0);
	if (!nvmeq)
		return -ENOMEM;

	aqa = nvmeq->q_depth - 1;
	aqa |= aqa << 16;

	dev->ctrl_config = NVME_CC_ENABLE | NVME_CC_CSS_NVM;
	dev->ctrl_config |= (PAGE_SHIFT - 12) << NVME_CC_MPS_SHIFT;
	dev->ctrl_config |= NVME_CC_ARB_RR | NVME_CC_SHN_NONE;
	dev->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;

	writel(0, &dev->bar->cc);
	writel(aqa, &dev->bar->aqa);
	writeq(nvmeq->sq_dma_addr, &dev->bar->asq);
	writeq(nvmeq->cq_dma_addr, &dev->bar->acq);
	writel(dev->ctrl_config, &dev->bar->cc);

	cap = readq(&dev->bar->cap);
	timeout = ((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
	dev->db_stride = NVME_CAP_STRIDE(cap);

	while (!(readl(&dev->bar->csts) & NVME_CSTS_RDY)) {
		msleep(100);
		if (fatal_signal_pending(current))
			return -EINTR;
		if (time_after(jiffies, timeout)) {
			dev_err(&dev->pci_dev->dev,
				"Device not ready; aborting initialisation\n");
			return -ENODEV;
		}
	}

	result = queue_request_irq(dev, nvmeq, "nvme admin");
	dev->queues[0] = nvmeq;
	return result;
}

static struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
				unsigned long addr, unsigned length)
{
	int i, err, count, nents, offset;
	struct scatterlist *sg;
	struct page **pages;
	struct nvme_iod *iod;

	if (addr & 3)
		return ERR_PTR(-EINVAL);
	if (!length)
		return ERR_PTR(-EINVAL);

	offset = offset_in_page(addr);
	count = DIV_ROUND_UP(offset + length, PAGE_SIZE);
	pages = kcalloc(count, sizeof(*pages), GFP_KERNEL);

	err = get_user_pages_fast(addr, count, 1, pages);
	if (err < count) {
		count = err;
		err = -EFAULT;
		goto put_pages;
	}

	iod = nvme_alloc_iod(count, length, GFP_KERNEL);
	sg = iod->sg;
	sg_init_table(sg, count);
	for (i = 0; i < count; i++) {
		sg_set_page(&sg[i], pages[i],
				min_t(int, length, PAGE_SIZE - offset), offset);
		length -= (PAGE_SIZE - offset);
		offset = 0;
	}
	sg_mark_end(&sg[i - 1]);
	iod->nents = count;

	err = -ENOMEM;
	nents = dma_map_sg(&dev->pci_dev->dev, sg, count,
				write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	if (!nents)
		goto free_iod;

	kfree(pages);
	return iod;

 free_iod:
	kfree(iod);
 put_pages:
	for (i = 0; i < count; i++)
		put_page(pages[i]);
	kfree(pages);
	return ERR_PTR(err);
}

static void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
			struct nvme_iod *iod)
{
	int i;

	dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
				write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

	for (i = 0; i < iod->nents; i++)
		put_page(sg_page(&iod->sg[i]));
}

static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
{
	struct nvme_dev *dev = ns->dev;
	struct nvme_queue *nvmeq;
	struct nvme_user_io io;
	struct nvme_command c;
	unsigned length;
	int status;
	struct nvme_iod *iod;

	if (copy_from_user(&io, uio, sizeof(io)))
		return -EFAULT;
	length = (io.nblocks + 1) << ns->lba_shift;

	switch (io.opcode) {
	case nvme_cmd_write:
	case nvme_cmd_read:
	case nvme_cmd_compare:
		iod = nvme_map_user_pages(dev, io.opcode & 1, io.addr, length);
		break;
	default:
		return -EINVAL;
	}

	if (IS_ERR(iod))
		return PTR_ERR(iod);

	memset(&c, 0, sizeof(c));
	c.rw.opcode = io.opcode;
	c.rw.flags = io.flags;
	c.rw.nsid = cpu_to_le32(ns->ns_id);
	c.rw.slba = cpu_to_le64(io.slba);
	c.rw.length = cpu_to_le16(io.nblocks);
	c.rw.control = cpu_to_le16(io.control);
	c.rw.dsmgmt = cpu_to_le16(io.dsmgmt);
	c.rw.reftag = io.reftag;
	c.rw.apptag = io.apptag;
	c.rw.appmask = io.appmask;
	/* XXX: metadata */
	length = nvme_setup_prps(dev, &c.common, iod, length, GFP_KERNEL);

	nvmeq = get_nvmeq(dev);
	/*
	 * Since nvme_submit_sync_cmd sleeps, we can't keep preemption
	 * disabled.  We may be preempted at any point, and be rescheduled
	 * to a different CPU.  That will cause cacheline bouncing, but no
	 * additional races since q_lock already protects against other CPUs.
	 */
	put_nvmeq(nvmeq);
	if (length != (io.nblocks + 1) << ns->lba_shift)
		status = -ENOMEM;
	else
		status = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);

	nvme_unmap_user_pages(dev, io.opcode & 1, iod);
	nvme_free_iod(dev, iod);
	return status;
}

static int nvme_user_admin_cmd(struct nvme_ns *ns,
					struct nvme_admin_cmd __user *ucmd)
{
	struct nvme_dev *dev = ns->dev;
	struct nvme_admin_cmd cmd;
	struct nvme_command c;
	int status, length;
	struct nvme_iod *iod;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;
	if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
		return -EFAULT;

	memset(&c, 0, sizeof(c));
	c.common.opcode = cmd.opcode;
	c.common.flags = cmd.flags;
	c.common.nsid = cpu_to_le32(cmd.nsid);
	c.common.cdw2[0] = cpu_to_le32(cmd.cdw2);
	c.common.cdw2[1] = cpu_to_le32(cmd.cdw3);
	c.common.cdw10[0] = cpu_to_le32(cmd.cdw10);
	c.common.cdw10[1] = cpu_to_le32(cmd.cdw11);
	c.common.cdw10[2] = cpu_to_le32(cmd.cdw12);
	c.common.cdw10[3] = cpu_to_le32(cmd.cdw13);
	c.common.cdw10[4] = cpu_to_le32(cmd.cdw14);
	c.common.cdw10[5] = cpu_to_le32(cmd.cdw15);

	length = cmd.data_len;
	if (cmd.data_len) {
		iod = nvme_map_user_pages(dev, cmd.opcode & 1, cmd.addr,
								length);
		if (IS_ERR(iod))
			return PTR_ERR(iod);
		length = nvme_setup_prps(dev, &c.common, iod, length,
								GFP_KERNEL);
	}

	if (length != cmd.data_len)
		status = -ENOMEM;
	else
		status = nvme_submit_admin_cmd(dev, &c, NULL);

	if (cmd.data_len) {
		nvme_unmap_user_pages(dev, cmd.opcode & 1, iod);
		nvme_free_iod(dev, iod);
	}
	return status;
}

static int nvme_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd,
							unsigned long arg)
{
	struct nvme_ns *ns = bdev->bd_disk->private_data;

	switch (cmd) {
	case NVME_IOCTL_ID:
		return ns->ns_id;
	case NVME_IOCTL_ADMIN_CMD:
		return nvme_user_admin_cmd(ns, (void __user *)arg);
	case NVME_IOCTL_SUBMIT_IO:
		return nvme_submit_io(ns, (void __user *)arg);
	default:
		return -ENOTTY;
	}
}

static const struct block_device_operations nvme_fops = {
	.owner		= THIS_MODULE,
	.ioctl		= nvme_ioctl,
	.compat_ioctl	= nvme_ioctl,
};

static void nvme_timeout_ios(struct nvme_queue *nvmeq)
{
	int depth = nvmeq->q_depth - 1;
	struct nvme_cmd_info *info = nvme_cmd_info(nvmeq);
	unsigned long now = jiffies;
	int cmdid;

	for_each_set_bit(cmdid, nvmeq->cmdid_data, depth) {
		void *ctx;
		nvme_completion_fn fn;
		static struct nvme_completion cqe = { .status = cpu_to_le16(NVME_SC_ABORT_REQ) << 1, };

		if (!time_after(now, info[cmdid].timeout))
			continue;
		dev_warn(nvmeq->q_dmadev, "Timing out I/O %d\n", cmdid);
		ctx = cancel_cmdid(nvmeq, cmdid, &fn);
		fn(nvmeq->dev, ctx, &cqe);
	}
}

static void nvme_resubmit_bios(struct nvme_queue *nvmeq)
{
	while (bio_list_peek(&nvmeq->sq_cong)) {
		struct bio *bio = bio_list_pop(&nvmeq->sq_cong);
		struct nvme_ns *ns = bio->bi_bdev->bd_disk->private_data;
		if (nvme_submit_bio_queue(nvmeq, ns, bio)) {
			bio_list_add_head(&nvmeq->sq_cong, bio);
			break;
		}
		if (bio_list_empty(&nvmeq->sq_cong))
			remove_wait_queue(&nvmeq->sq_full,
							&nvmeq->sq_cong_wait);
	}
}

static int nvme_kthread(void *data)
{
	struct nvme_dev *dev;

	while (!kthread_should_stop()) {
		__set_current_state(TASK_RUNNING);
		spin_lock(&dev_list_lock);
		list_for_each_entry(dev, &dev_list, node) {
			int i;
			for (i = 0; i < dev->queue_count; i++) {
				struct nvme_queue *nvmeq = dev->queues[i];
				if (!nvmeq)
					continue;
				spin_lock_irq(&nvmeq->q_lock);
				if (nvme_process_cq(nvmeq))
					printk("process_cq did something\n");
				nvme_timeout_ios(nvmeq);
				nvme_resubmit_bios(nvmeq);
				spin_unlock_irq(&nvmeq->q_lock);
			}
		}
		spin_unlock(&dev_list_lock);
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(HZ);
	}
	return 0;
}

static DEFINE_IDA(nvme_index_ida);

static int nvme_get_ns_idx(void)
{
	int index, error;

	do {
		if (!ida_pre_get(&nvme_index_ida, GFP_KERNEL))
			return -1;

		spin_lock(&dev_list_lock);
		error = ida_get_new(&nvme_index_ida, &index);
		spin_unlock(&dev_list_lock);
	} while (error == -EAGAIN);

	if (error)
		index = -1;
	return index;
}

static void nvme_put_ns_idx(int index)
{
	spin_lock(&dev_list_lock);
	ida_remove(&nvme_index_ida, index);
	spin_unlock(&dev_list_lock);
}

static struct nvme_ns *nvme_alloc_ns(struct nvme_dev *dev, int nsid,
			struct nvme_id_ns *id, struct nvme_lba_range_type *rt)
{
	struct nvme_ns *ns;
	struct gendisk *disk;
	int lbaf;

	if (rt->attributes & NVME_LBART_ATTRIB_HIDE)
		return NULL;

	ns = kzalloc(sizeof(*ns), GFP_KERNEL);
	if (!ns)
		return NULL;
	ns->queue = blk_alloc_queue(GFP_KERNEL);
	if (!ns->queue)
		goto out_free_ns;
	ns->queue->queue_flags = QUEUE_FLAG_DEFAULT;
	queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, ns->queue);
	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, ns->queue);
/*	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, ns->queue); */
	blk_queue_make_request(ns->queue, nvme_make_request);
	ns->dev = dev;
	ns->queue->queuedata = ns;

	disk = alloc_disk(NVME_MINORS);
	if (!disk)
		goto out_free_queue;
	ns->ns_id = nsid;
	ns->disk = disk;
	lbaf = id->flbas & 0xf;
	ns->lba_shift = id->lbaf[lbaf].ds;

	disk->major = nvme_major;
	disk->minors = NVME_MINORS;
	disk->first_minor = NVME_MINORS * nvme_get_ns_idx();
	disk->fops = &nvme_fops;
	disk->private_data = ns;
	disk->queue = ns->queue;
	disk->driverfs_dev = &dev->pci_dev->dev;
	sprintf(disk->disk_name, "nvme%dn%d", dev->instance, nsid);
	set_capacity(disk, le64_to_cpup(&id->nsze) << (ns->lba_shift - 9));

	return ns;

 out_free_queue:
	blk_cleanup_queue(ns->queue);
 out_free_ns:
	kfree(ns);
	return NULL;
}

static void nvme_ns_free(struct nvme_ns *ns)
{
	int index = ns->disk->first_minor / NVME_MINORS;
	put_disk(ns->disk);
	nvme_put_ns_idx(index);
	blk_cleanup_queue(ns->queue);
	kfree(ns);
}

static int set_queue_count(struct nvme_dev *dev, int count)
{
	int status;
	u32 result;
	u32 q_count = (count - 1) | ((count - 1) << 16);

	status = nvme_set_features(dev, NVME_FEAT_NUM_QUEUES, q_count, 0,
								&result);
	if (status)
		return -EIO;
	return min(result & 0xffff, result >> 16) + 1;
}

static int __devinit nvme_setup_io_queues(struct nvme_dev *dev)
{
	int result, cpu, i, nr_io_queues, db_bar_size;

	nr_io_queues = num_online_cpus();
	result = set_queue_count(dev, nr_io_queues);
	if (result < 0)
		return result;
	if (result < nr_io_queues)
		nr_io_queues = result;

	/* Deregister the admin queue's interrupt */
	free_irq(dev->entry[0].vector, dev->queues[0]);

	db_bar_size = 4096 + ((nr_io_queues + 1) << (dev->db_stride + 3));
	if (db_bar_size > 8192) {
		iounmap(dev->bar);
		dev->bar = ioremap(pci_resource_start(dev->pci_dev, 0),
								db_bar_size);
		dev->dbs = ((void __iomem *)dev->bar) + 4096;
		dev->queues[0]->q_db = dev->dbs;
	}

	for (i = 0; i < nr_io_queues; i++)
		dev->entry[i].entry = i;
	for (;;) {
		result = pci_enable_msix(dev->pci_dev, dev->entry,
								nr_io_queues);
		if (result == 0) {
			break;
		} else if (result > 0) {
			nr_io_queues = result;
			continue;
		} else {
			nr_io_queues = 1;
			break;
		}
	}

	result = queue_request_irq(dev, dev->queues[0], "nvme admin");
	/* XXX: handle failure here */

	cpu = cpumask_first(cpu_online_mask);
	for (i = 0; i < nr_io_queues; i++) {
		irq_set_affinity_hint(dev->entry[i].vector, get_cpu_mask(cpu));
		cpu = cpumask_next(cpu, cpu_online_mask);
	}

	for (i = 0; i < nr_io_queues; i++) {
		dev->queues[i + 1] = nvme_create_queue(dev, i + 1,
							NVME_Q_DEPTH, i);
		if (IS_ERR(dev->queues[i + 1]))
			return PTR_ERR(dev->queues[i + 1]);
		dev->queue_count++;
	}

	for (; i < num_possible_cpus(); i++) {
		int target = i % rounddown_pow_of_two(dev->queue_count - 1);
		dev->queues[i + 1] = dev->queues[target + 1];
	}

	return 0;
}

static void nvme_free_queues(struct nvme_dev *dev)
{
	int i;

	for (i = dev->queue_count - 1; i >= 0; i--)
		nvme_free_queue(dev, i);
}

static int __devinit nvme_dev_add(struct nvme_dev *dev)
{
	int res, nn, i;
	struct nvme_ns *ns, *next;
	struct nvme_id_ctrl *ctrl;
	struct nvme_id_ns *id_ns;
	void *mem;
	dma_addr_t dma_addr;

	res = nvme_setup_io_queues(dev);
	if (res)
		return res;

	mem = dma_alloc_coherent(&dev->pci_dev->dev, 8192, &dma_addr,
								GFP_KERNEL);

	res = nvme_identify(dev, 0, 1, dma_addr);
	if (res) {
		res = -EIO;
		goto out_free;
	}

	ctrl = mem;
	nn = le32_to_cpup(&ctrl->nn);
	memcpy(dev->serial, ctrl->sn, sizeof(ctrl->sn));
	memcpy(dev->model, ctrl->mn, sizeof(ctrl->mn));
	memcpy(dev->firmware_rev, ctrl->fr, sizeof(ctrl->fr));

	id_ns = mem;
	for (i = 1; i <= nn; i++) {
		res = nvme_identify(dev, i, 0, dma_addr);
		if (res)
			continue;

		if (id_ns->ncap == 0)
			continue;

		res = nvme_get_features(dev, NVME_FEAT_LBA_RANGE, i,
							dma_addr + 4096);
		if (res)
			continue;

		ns = nvme_alloc_ns(dev, i, mem, mem + 4096);
		if (ns)
			list_add_tail(&ns->list, &dev->namespaces);
	}
	list_for_each_entry(ns, &dev->namespaces, list)
		add_disk(ns->disk);

	goto out;

 out_free:
	list_for_each_entry_safe(ns, next, &dev->namespaces, list) {
		list_del(&ns->list);
		nvme_ns_free(ns);
	}

 out:
	dma_free_coherent(&dev->pci_dev->dev, 8192, mem, dma_addr);
	return res;
}

static int nvme_dev_remove(struct nvme_dev *dev)
{
	struct nvme_ns *ns, *next;

	spin_lock(&dev_list_lock);
	list_del(&dev->node);
	spin_unlock(&dev_list_lock);

	/* TODO: wait all I/O finished or cancel them */

	list_for_each_entry_safe(ns, next, &dev->namespaces, list) {
		list_del(&ns->list);
		del_gendisk(ns->disk);
		nvme_ns_free(ns);
	}

	nvme_free_queues(dev);

	return 0;
}

static int nvme_setup_prp_pools(struct nvme_dev *dev)
{
	struct device *dmadev = &dev->pci_dev->dev;
	dev->prp_page_pool = dma_pool_create("prp list page", dmadev,
						PAGE_SIZE, PAGE_SIZE, 0);
	if (!dev->prp_page_pool)
		return -ENOMEM;

	/* Optimisation for I/Os between 4k and 128k */
	dev->prp_small_pool = dma_pool_create("prp list 256", dmadev,
						256, 256, 0);
	if (!dev->prp_small_pool) {
		dma_pool_destroy(dev->prp_page_pool);
		return -ENOMEM;
	}
	return 0;
}

static void nvme_release_prp_pools(struct nvme_dev *dev)
{
	dma_pool_destroy(dev->prp_page_pool);
	dma_pool_destroy(dev->prp_small_pool);
}

/* XXX: Use an ida or something to let remove / add work correctly */
static void nvme_set_instance(struct nvme_dev *dev)
{
	static int instance;
	dev->instance = instance++;
}

static void nvme_release_instance(struct nvme_dev *dev)
{
}

static int __devinit nvme_probe(struct pci_dev *pdev,
						const struct pci_device_id *id)
{
	int bars, result = -ENOMEM;
	struct nvme_dev *dev;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;
	dev->entry = kcalloc(num_possible_cpus(), sizeof(*dev->entry),
								GFP_KERNEL);
	if (!dev->entry)
		goto free;
	dev->queues = kcalloc(num_possible_cpus() + 1, sizeof(void *),
								GFP_KERNEL);
	if (!dev->queues)
		goto free;

	if (pci_enable_device_mem(pdev))
		goto free;
	pci_set_master(pdev);
	bars = pci_select_bars(pdev, IORESOURCE_MEM);
	if (pci_request_selected_regions(pdev, bars, "nvme"))
		goto disable;

	INIT_LIST_HEAD(&dev->namespaces);
	dev->pci_dev = pdev;
	pci_set_drvdata(pdev, dev);
	dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
	dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64));
	nvme_set_instance(dev);
	dev->entry[0].vector = pdev->irq;

	result = nvme_setup_prp_pools(dev);
	if (result)
		goto disable_msix;

	dev->bar = ioremap(pci_resource_start(pdev, 0), 8192);
	if (!dev->bar) {
		result = -ENOMEM;
		goto disable_msix;
	}

	result = nvme_configure_admin_queue(dev);
	if (result)
		goto unmap;
	dev->queue_count++;

	spin_lock(&dev_list_lock);
	list_add(&dev->node, &dev_list);
	spin_unlock(&dev_list_lock);

	result = nvme_dev_add(dev);
	if (result)
		goto delete;

	return 0;

 delete:
	spin_lock(&dev_list_lock);
	list_del(&dev->node);
	spin_unlock(&dev_list_lock);

	nvme_free_queues(dev);
 unmap:
	iounmap(dev->bar);
 disable_msix:
	pci_disable_msix(pdev);
	nvme_release_instance(dev);
	nvme_release_prp_pools(dev);
 disable:
	pci_disable_device(pdev);
	pci_release_regions(pdev);
 free:
	kfree(dev->queues);
	kfree(dev->entry);
	kfree(dev);
	return result;
}

static void __devexit nvme_remove(struct pci_dev *pdev)
{
	struct nvme_dev *dev = pci_get_drvdata(pdev);
	nvme_dev_remove(dev);
	pci_disable_msix(pdev);
	iounmap(dev->bar);
	nvme_release_instance(dev);
	nvme_release_prp_pools(dev);
	pci_disable_device(pdev);
	pci_release_regions(pdev);
	kfree(dev->queues);
	kfree(dev->entry);
	kfree(dev);
}

/* These functions are yet to be implemented */
#define nvme_error_detected NULL
#define nvme_dump_registers NULL
#define nvme_link_reset NULL
#define nvme_slot_reset NULL
#define nvme_error_resume NULL
#define nvme_suspend NULL
#define nvme_resume NULL

static struct pci_error_handlers nvme_err_handler = {
	.error_detected	= nvme_error_detected,
	.mmio_enabled	= nvme_dump_registers,
	.link_reset	= nvme_link_reset,
	.slot_reset	= nvme_slot_reset,
	.resume		= nvme_error_resume,
};

/* Move to pci_ids.h later */
#define PCI_CLASS_STORAGE_EXPRESS	0x010802

static DEFINE_PCI_DEVICE_TABLE(nvme_id_table) = {
	{ PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, 0xffffff) },
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, nvme_id_table);

static struct pci_driver nvme_driver = {
	.name		= "nvme",
	.id_table	= nvme_id_table,
	.probe		= nvme_probe,
	.remove		= __devexit_p(nvme_remove),
	.suspend	= nvme_suspend,
	.resume		= nvme_resume,
	.err_handler	= &nvme_err_handler,
};

static int __init nvme_init(void)
{
	int result = -EBUSY;

	nvme_thread = kthread_run(nvme_kthread, NULL, "nvme");
	if (IS_ERR(nvme_thread))
		return PTR_ERR(nvme_thread);

	nvme_major = register_blkdev(nvme_major, "nvme");
	if (nvme_major <= 0)
		goto kill_kthread;

	result = pci_register_driver(&nvme_driver);
	if (result)
		goto unregister_blkdev;
	return 0;

 unregister_blkdev:
	unregister_blkdev(nvme_major, "nvme");
 kill_kthread:
	kthread_stop(nvme_thread);
	return result;
}

static void __exit nvme_exit(void)
{
	pci_unregister_driver(&nvme_driver);
	unregister_blkdev(nvme_major, "nvme");
	kthread_stop(nvme_thread);
}

MODULE_AUTHOR("Matthew Wilcox <willy@linux.intel.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.8");
module_init(nvme_init);
module_exit(nvme_exit);