summaryrefslogtreecommitdiffstats
path: root/drivers/scsi/libsas/sas_scsi_host.c
blob: a8e3ef309070ae9e0da26381668e0bd847b68e0b (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
/*
 * Serial Attached SCSI (SAS) class SCSI Host glue.
 *
 * Copyright (C) 2005 Adaptec, Inc.  All rights reserved.
 * Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
 *
 * This file is licensed under GPLv2.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 *
 */

#include <linux/kthread.h>
#include <linux/firmware.h>
#include <linux/ctype.h>

#include "sas_internal.h"

#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_sas.h>
#include <scsi/sas_ata.h>
#include "../scsi_sas_internal.h"
#include "../scsi_transport_api.h"
#include "../scsi_priv.h"

#include <linux/err.h>
#include <linux/blkdev.h>
#include <linux/freezer.h>
#include <linux/scatterlist.h>
#include <linux/libata.h>

/* ---------- SCSI Host glue ---------- */

static void sas_scsi_task_done(struct sas_task *task)
{
	struct task_status_struct *ts = &task->task_status;
	struct scsi_cmnd *sc = task->uldd_task;
	int hs = 0, stat = 0;

	if (unlikely(task->task_state_flags & SAS_TASK_STATE_ABORTED)) {
		/* Aborted tasks will be completed by the error handler */
		SAS_DPRINTK("task done but aborted\n");
		return;
	}

	if (unlikely(!sc)) {
		SAS_DPRINTK("task_done called with non existing SCSI cmnd!\n");
		list_del_init(&task->list);
		sas_free_task(task);
		return;
	}

	if (ts->resp == SAS_TASK_UNDELIVERED) {
		/* transport error */
		hs = DID_NO_CONNECT;
	} else { /* ts->resp == SAS_TASK_COMPLETE */
		/* task delivered, what happened afterwards? */
		switch (ts->stat) {
		case SAS_DEV_NO_RESPONSE:
		case SAS_INTERRUPTED:
		case SAS_PHY_DOWN:
		case SAS_NAK_R_ERR:
		case SAS_OPEN_TO:
			hs = DID_NO_CONNECT;
			break;
		case SAS_DATA_UNDERRUN:
			scsi_set_resid(sc, ts->residual);
			if (scsi_bufflen(sc) - scsi_get_resid(sc) < sc->underflow)
				hs = DID_ERROR;
			break;
		case SAS_DATA_OVERRUN:
			hs = DID_ERROR;
			break;
		case SAS_QUEUE_FULL:
			hs = DID_SOFT_ERROR; /* retry */
			break;
		case SAS_DEVICE_UNKNOWN:
			hs = DID_BAD_TARGET;
			break;
		case SAS_SG_ERR:
			hs = DID_PARITY;
			break;
		case SAS_OPEN_REJECT:
			if (ts->open_rej_reason == SAS_OREJ_RSVD_RETRY)
				hs = DID_SOFT_ERROR; /* retry */
			else
				hs = DID_ERROR;
			break;
		case SAS_PROTO_RESPONSE:
			SAS_DPRINTK("LLDD:%s sent SAS_PROTO_RESP for an SSP "
				    "task; please report this\n",
				    task->dev->port->ha->sas_ha_name);
			break;
		case SAS_ABORTED_TASK:
			hs = DID_ABORT;
			break;
		case SAM_CHECK_COND:
			memcpy(sc->sense_buffer, ts->buf,
			       min(SCSI_SENSE_BUFFERSIZE, ts->buf_valid_size));
			stat = SAM_CHECK_COND;
			break;
		default:
			stat = ts->stat;
			break;
		}
	}
	ASSIGN_SAS_TASK(sc, NULL);
	sc->result = (hs << 16) | stat;
	list_del_init(&task->list);
	sas_free_task(task);
	sc->scsi_done(sc);
}

static enum task_attribute sas_scsi_get_task_attr(struct scsi_cmnd *cmd)
{
	enum task_attribute ta = TASK_ATTR_SIMPLE;
	if (cmd->request && blk_rq_tagged(cmd->request)) {
		if (cmd->device->ordered_tags &&
		    (cmd->request->cmd_flags & REQ_HARDBARRIER))
			ta = TASK_ATTR_ORDERED;
	}
	return ta;
}

static struct sas_task *sas_create_task(struct scsi_cmnd *cmd,
					       struct domain_device *dev,
					       gfp_t gfp_flags)
{
	struct sas_task *task = sas_alloc_task(gfp_flags);
	struct scsi_lun lun;

	if (!task)
		return NULL;

	task->uldd_task = cmd;
	ASSIGN_SAS_TASK(cmd, task);

	task->dev = dev;
	task->task_proto = task->dev->tproto; /* BUG_ON(!SSP) */

	task->ssp_task.retry_count = 1;
	int_to_scsilun(cmd->device->lun, &lun);
	memcpy(task->ssp_task.LUN, &lun.scsi_lun, 8);
	task->ssp_task.task_attr = sas_scsi_get_task_attr(cmd);
	memcpy(task->ssp_task.cdb, cmd->cmnd, 16);

	task->scatter = scsi_sglist(cmd);
	task->num_scatter = scsi_sg_count(cmd);
	task->total_xfer_len = scsi_bufflen(cmd);
	task->data_dir = cmd->sc_data_direction;

	task->task_done = sas_scsi_task_done;

	return task;
}

int sas_queue_up(struct sas_task *task)
{
	struct sas_ha_struct *sas_ha = task->dev->port->ha;
	struct scsi_core *core = &sas_ha->core;
	unsigned long flags;
	LIST_HEAD(list);

	spin_lock_irqsave(&core->task_queue_lock, flags);
	if (sas_ha->lldd_queue_size < core->task_queue_size + 1) {
		spin_unlock_irqrestore(&core->task_queue_lock, flags);
		return -SAS_QUEUE_FULL;
	}
	list_add_tail(&task->list, &core->task_queue);
	core->task_queue_size += 1;
	spin_unlock_irqrestore(&core->task_queue_lock, flags);
	wake_up_process(core->queue_thread);

	return 0;
}

/**
 * sas_queuecommand -- Enqueue a command for processing
 * @parameters: See SCSI Core documentation
 *
 * Note: XXX: Remove the host unlock/lock pair when SCSI Core can
 * call us without holding an IRQ spinlock...
 */
int sas_queuecommand(struct scsi_cmnd *cmd,
		     void (*scsi_done)(struct scsi_cmnd *))
	__releases(host->host_lock)
	__acquires(dev->sata_dev.ap->lock)
	__releases(dev->sata_dev.ap->lock)
	__acquires(host->host_lock)
{
	int res = 0;
	struct domain_device *dev = cmd_to_domain_dev(cmd);
	struct Scsi_Host *host = cmd->device->host;
	struct sas_internal *i = to_sas_internal(host->transportt);

	spin_unlock_irq(host->host_lock);

	{
		struct sas_ha_struct *sas_ha = dev->port->ha;
		struct sas_task *task;

		if (dev_is_sata(dev)) {
			unsigned long flags;

			spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
			res = ata_sas_queuecmd(cmd, scsi_done,
					       dev->sata_dev.ap);
			spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
			goto out;
		}

		res = -ENOMEM;
		task = sas_create_task(cmd, dev, GFP_ATOMIC);
		if (!task)
			goto out;

		cmd->scsi_done = scsi_done;
		/* Queue up, Direct Mode or Task Collector Mode. */
		if (sas_ha->lldd_max_execute_num < 2)
			res = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);
		else
			res = sas_queue_up(task);

		/* Examine */
		if (res) {
			SAS_DPRINTK("lldd_execute_task returned: %d\n", res);
			ASSIGN_SAS_TASK(cmd, NULL);
			sas_free_task(task);
			if (res == -SAS_QUEUE_FULL) {
				cmd->result = DID_SOFT_ERROR << 16; /* retry */
				res = 0;
				scsi_done(cmd);
			}
			goto out;
		}
	}
out:
	spin_lock_irq(host->host_lock);
	return res;
}

static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
{
	struct sas_task *task = TO_SAS_TASK(cmd);
	struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host);

	/* remove the aborted task flag to allow the task to be
	 * completed now. At this point, we only get called following
	 * an actual abort of the task, so we should be guaranteed not
	 * to be racing with any completions from the LLD (hence we
	 * don't need the task state lock to clear the flag) */
	task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
	/* Now call task_done.  However, task will be free'd after
	 * this */
	task->task_done(task);
	/* now finish the command and move it on to the error
	 * handler done list, this also takes it off the
	 * error handler pending list */
	scsi_eh_finish_cmd(cmd, &sas_ha->eh_done_q);
}

static void sas_scsi_clear_queue_lu(struct list_head *error_q, struct scsi_cmnd *my_cmd)
{
	struct scsi_cmnd *cmd, *n;

	list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
		if (cmd->device->sdev_target == my_cmd->device->sdev_target &&
		    cmd->device->lun == my_cmd->device->lun)
			sas_eh_finish_cmd(cmd);
	}
}

static void sas_scsi_clear_queue_I_T(struct list_head *error_q,
				     struct domain_device *dev)
{
	struct scsi_cmnd *cmd, *n;

	list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
		struct domain_device *x = cmd_to_domain_dev(cmd);

		if (x == dev)
			sas_eh_finish_cmd(cmd);
	}
}

static void sas_scsi_clear_queue_port(struct list_head *error_q,
				      struct asd_sas_port *port)
{
	struct scsi_cmnd *cmd, *n;

	list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
		struct domain_device *dev = cmd_to_domain_dev(cmd);
		struct asd_sas_port *x = dev->port;

		if (x == port)
			sas_eh_finish_cmd(cmd);
	}
}

enum task_disposition {
	TASK_IS_DONE,
	TASK_IS_ABORTED,
	TASK_IS_AT_LU,
	TASK_IS_NOT_AT_LU,
	TASK_ABORT_FAILED,
};

static enum task_disposition sas_scsi_find_task(struct sas_task *task)
{
	struct sas_ha_struct *ha = task->dev->port->ha;
	unsigned long flags;
	int i, res;
	struct sas_internal *si =
		to_sas_internal(task->dev->port->ha->core.shost->transportt);

	if (ha->lldd_max_execute_num > 1) {
		struct scsi_core *core = &ha->core;
		struct sas_task *t, *n;

		spin_lock_irqsave(&core->task_queue_lock, flags);
		list_for_each_entry_safe(t, n, &core->task_queue, list) {
			if (task == t) {
				list_del_init(&t->list);
				spin_unlock_irqrestore(&core->task_queue_lock,
						       flags);
				SAS_DPRINTK("%s: task 0x%p aborted from "
					    "task_queue\n",
					    __func__, task);
				return TASK_IS_ABORTED;
			}
		}
		spin_unlock_irqrestore(&core->task_queue_lock, flags);
	}

	for (i = 0; i < 5; i++) {
		SAS_DPRINTK("%s: aborting task 0x%p\n", __func__, task);
		res = si->dft->lldd_abort_task(task);

		spin_lock_irqsave(&task->task_state_lock, flags);
		if (task->task_state_flags & SAS_TASK_STATE_DONE) {
			spin_unlock_irqrestore(&task->task_state_lock, flags);
			SAS_DPRINTK("%s: task 0x%p is done\n", __func__,
				    task);
			return TASK_IS_DONE;
		}
		spin_unlock_irqrestore(&task->task_state_lock, flags);

		if (res == TMF_RESP_FUNC_COMPLETE) {
			SAS_DPRINTK("%s: task 0x%p is aborted\n",
				    __func__, task);
			return TASK_IS_ABORTED;
		} else if (si->dft->lldd_query_task) {
			SAS_DPRINTK("%s: querying task 0x%p\n",
				    __func__, task);
			res = si->dft->lldd_query_task(task);
			switch (res) {
			case TMF_RESP_FUNC_SUCC:
				SAS_DPRINTK("%s: task 0x%p at LU\n",
					    __func__, task);
				return TASK_IS_AT_LU;
			case TMF_RESP_FUNC_COMPLETE:
				SAS_DPRINTK("%s: task 0x%p not at LU\n",
					    __func__, task);
				return TASK_IS_NOT_AT_LU;
			case TMF_RESP_FUNC_FAILED:
                                SAS_DPRINTK("%s: task 0x%p failed to abort\n",
                                                __func__, task);
                                return TASK_ABORT_FAILED;
                        }

		}
	}
	return res;
}

static int sas_recover_lu(struct domain_device *dev, struct scsi_cmnd *cmd)
{
	int res = TMF_RESP_FUNC_FAILED;
	struct scsi_lun lun;
	struct sas_internal *i =
		to_sas_internal(dev->port->ha->core.shost->transportt);

	int_to_scsilun(cmd->device->lun, &lun);

	SAS_DPRINTK("eh: device %llx LUN %x has the task\n",
		    SAS_ADDR(dev->sas_addr),
		    cmd->device->lun);

	if (i->dft->lldd_abort_task_set)
		res = i->dft->lldd_abort_task_set(dev, lun.scsi_lun);

	if (res == TMF_RESP_FUNC_FAILED) {
		if (i->dft->lldd_clear_task_set)
			res = i->dft->lldd_clear_task_set(dev, lun.scsi_lun);
	}

	if (res == TMF_RESP_FUNC_FAILED) {
		if (i->dft->lldd_lu_reset)
			res = i->dft->lldd_lu_reset(dev, lun.scsi_lun);
	}

	return res;
}

static int sas_recover_I_T(struct domain_device *dev)
{
	int res = TMF_RESP_FUNC_FAILED;
	struct sas_internal *i =
		to_sas_internal(dev->port->ha->core.shost->transportt);

	SAS_DPRINTK("I_T nexus reset for dev %016llx\n",
		    SAS_ADDR(dev->sas_addr));

	if (i->dft->lldd_I_T_nexus_reset)
		res = i->dft->lldd_I_T_nexus_reset(dev);

	return res;
}

/* Find the sas_phy that's attached to this device */
struct sas_phy *sas_find_local_phy(struct domain_device *dev)
{
	struct domain_device *pdev = dev->parent;
	struct ex_phy *exphy = NULL;
	int i;

	/* Directly attached device */
	if (!pdev)
		return dev->port->phy;

	/* Otherwise look in the expander */
	for (i = 0; i < pdev->ex_dev.num_phys; i++)
		if (!memcmp(dev->sas_addr,
			    pdev->ex_dev.ex_phy[i].attached_sas_addr,
			    SAS_ADDR_SIZE)) {
			exphy = &pdev->ex_dev.ex_phy[i];
			break;
		}

	BUG_ON(!exphy);
	return exphy->phy;
}
EXPORT_SYMBOL_GPL(sas_find_local_phy);

/* Attempt to send a LUN reset message to a device */
int sas_eh_device_reset_handler(struct scsi_cmnd *cmd)
{
	struct domain_device *dev = cmd_to_domain_dev(cmd);
	struct sas_internal *i =
		to_sas_internal(dev->port->ha->core.shost->transportt);
	struct scsi_lun lun;
	int res;

	int_to_scsilun(cmd->device->lun, &lun);

	if (!i->dft->lldd_lu_reset)
		return FAILED;

	res = i->dft->lldd_lu_reset(dev, lun.scsi_lun);
	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE)
		return SUCCESS;

	return FAILED;
}

/* Attempt to send a phy (bus) reset */
int sas_eh_bus_reset_handler(struct scsi_cmnd *cmd)
{
	struct domain_device *dev = cmd_to_domain_dev(cmd);
	struct sas_phy *phy = sas_find_local_phy(dev);
	int res;

	res = sas_phy_reset(phy, 1);
	if (res)
		SAS_DPRINTK("Bus reset of %s failed 0x%x\n",
			    kobject_name(&phy->dev.kobj),
			    res);
	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE)
		return SUCCESS;

	return FAILED;
}

/* Try to reset a device */
static int try_to_reset_cmd_device(struct scsi_cmnd *cmd)
{
	int res;
	struct Scsi_Host *shost = cmd->device->host;

	if (!shost->hostt->eh_device_reset_handler)
		goto try_bus_reset;

	res = shost->hostt->eh_device_reset_handler(cmd);
	if (res == SUCCESS)
		return res;

try_bus_reset:
	if (shost->hostt->eh_bus_reset_handler)
		return shost->hostt->eh_bus_reset_handler(cmd);

	return FAILED;
}

static int sas_eh_handle_sas_errors(struct Scsi_Host *shost,
				    struct list_head *work_q,
				    struct list_head *done_q)
{
	struct scsi_cmnd *cmd, *n;
	enum task_disposition res = TASK_IS_DONE;
	int tmf_resp, need_reset;
	struct sas_internal *i = to_sas_internal(shost->transportt);
	unsigned long flags;
	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);

Again:
	list_for_each_entry_safe(cmd, n, work_q, eh_entry) {
		struct sas_task *task = TO_SAS_TASK(cmd);

		if (!task)
			continue;

		list_del_init(&cmd->eh_entry);

		spin_lock_irqsave(&task->task_state_lock, flags);
		need_reset = task->task_state_flags & SAS_TASK_NEED_DEV_RESET;
		spin_unlock_irqrestore(&task->task_state_lock, flags);

		if (need_reset) {
			SAS_DPRINTK("%s: task 0x%p requests reset\n",
				    __func__, task);
			goto reset;
		}

		SAS_DPRINTK("trying to find task 0x%p\n", task);
		res = sas_scsi_find_task(task);

		cmd->eh_eflags = 0;

		switch (res) {
		case TASK_IS_DONE:
			SAS_DPRINTK("%s: task 0x%p is done\n", __func__,
				    task);
			sas_eh_finish_cmd(cmd);
			continue;
		case TASK_IS_ABORTED:
			SAS_DPRINTK("%s: task 0x%p is aborted\n",
				    __func__, task);
			sas_eh_finish_cmd(cmd);
			continue;
		case TASK_IS_AT_LU:
			SAS_DPRINTK("task 0x%p is at LU: lu recover\n", task);
 reset:
			tmf_resp = sas_recover_lu(task->dev, cmd);
			if (tmf_resp == TMF_RESP_FUNC_COMPLETE) {
				SAS_DPRINTK("dev %016llx LU %x is "
					    "recovered\n",
					    SAS_ADDR(task->dev),
					    cmd->device->lun);
				sas_eh_finish_cmd(cmd);
				sas_scsi_clear_queue_lu(work_q, cmd);
				goto Again;
			}
			/* fallthrough */
		case TASK_IS_NOT_AT_LU:
		case TASK_ABORT_FAILED:
			SAS_DPRINTK("task 0x%p is not at LU: I_T recover\n",
				    task);
			tmf_resp = sas_recover_I_T(task->dev);
			if (tmf_resp == TMF_RESP_FUNC_COMPLETE) {
				struct domain_device *dev = task->dev;
				SAS_DPRINTK("I_T %016llx recovered\n",
					    SAS_ADDR(task->dev->sas_addr));
				sas_eh_finish_cmd(cmd);
				sas_scsi_clear_queue_I_T(work_q, dev);
				goto Again;
			}
			/* Hammer time :-) */
			try_to_reset_cmd_device(cmd);
			if (i->dft->lldd_clear_nexus_port) {
				struct asd_sas_port *port = task->dev->port;
				SAS_DPRINTK("clearing nexus for port:%d\n",
					    port->id);
				res = i->dft->lldd_clear_nexus_port(port);
				if (res == TMF_RESP_FUNC_COMPLETE) {
					SAS_DPRINTK("clear nexus port:%d "
						    "succeeded\n", port->id);
					sas_eh_finish_cmd(cmd);
					sas_scsi_clear_queue_port(work_q,
								  port);
					goto Again;
				}
			}
			if (i->dft->lldd_clear_nexus_ha) {
				SAS_DPRINTK("clear nexus ha\n");
				res = i->dft->lldd_clear_nexus_ha(ha);
				if (res == TMF_RESP_FUNC_COMPLETE) {
					SAS_DPRINTK("clear nexus ha "
						    "succeeded\n");
					sas_eh_finish_cmd(cmd);
					goto clear_q;
				}
			}
			/* If we are here -- this means that no amount
			 * of effort could recover from errors.  Quite
			 * possibly the HA just disappeared.
			 */
			SAS_DPRINTK("error from  device %llx, LUN %x "
				    "couldn't be recovered in any way\n",
				    SAS_ADDR(task->dev->sas_addr),
				    cmd->device->lun);

			sas_eh_finish_cmd(cmd);
			goto clear_q;
		}
	}
	return list_empty(work_q);
clear_q:
	SAS_DPRINTK("--- Exit %s -- clear_q\n", __func__);
	list_for_each_entry_safe(cmd, n, work_q, eh_entry)
		sas_eh_finish_cmd(cmd);

	return list_empty(work_q);
}

void sas_scsi_recover_host(struct Scsi_Host *shost)
{
	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
	unsigned long flags;
	LIST_HEAD(eh_work_q);

	spin_lock_irqsave(shost->host_lock, flags);
	list_splice_init(&shost->eh_cmd_q, &eh_work_q);
	spin_unlock_irqrestore(shost->host_lock, flags);

	SAS_DPRINTK("Enter %s\n", __func__);
	/*
	 * Deal with commands that still have SAS tasks (i.e. they didn't
	 * complete via the normal sas_task completion mechanism)
	 */
	if (sas_eh_handle_sas_errors(shost, &eh_work_q, &ha->eh_done_q))
		goto out;

	/*
	 * Now deal with SCSI commands that completed ok but have a an error
	 * code (and hopefully sense data) attached.  This is roughly what
	 * scsi_unjam_host does, but we skip scsi_eh_abort_cmds because any
	 * command we see here has no sas_task and is thus unknown to the HA.
	 */
	if (!scsi_eh_get_sense(&eh_work_q, &ha->eh_done_q))
		scsi_eh_ready_devs(shost, &eh_work_q, &ha->eh_done_q);

out:
	scsi_eh_flush_done_q(&ha->eh_done_q);
	SAS_DPRINTK("--- Exit %s\n", __func__);
	return;
}

enum scsi_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd)
{
	struct sas_task *task = TO_SAS_TASK(cmd);
	unsigned long flags;

	if (!task) {
		cmd->timeout_per_command /= 2;
		SAS_DPRINTK("command 0x%p, task 0x%p, gone: %s\n",
			    cmd, task, (cmd->timeout_per_command ?
			    "EH_RESET_TIMER" : "EH_NOT_HANDLED"));
		if (!cmd->timeout_per_command)
			return EH_NOT_HANDLED;
		return EH_RESET_TIMER;
	}

	spin_lock_irqsave(&task->task_state_lock, flags);
	BUG_ON(task->task_state_flags & SAS_TASK_STATE_ABORTED);
	if (task->task_state_flags & SAS_TASK_STATE_DONE) {
		spin_unlock_irqrestore(&task->task_state_lock, flags);
		SAS_DPRINTK("command 0x%p, task 0x%p, timed out: EH_HANDLED\n",
			    cmd, task);
		return EH_HANDLED;
	}
	if (!(task->task_state_flags & SAS_TASK_AT_INITIATOR)) {
		spin_unlock_irqrestore(&task->task_state_lock, flags);
		SAS_DPRINTK("command 0x%p, task 0x%p, not at initiator: "
			    "EH_RESET_TIMER\n",
			    cmd, task);
		return EH_RESET_TIMER;
	}
	task->task_state_flags |= SAS_TASK_STATE_ABORTED;
	spin_unlock_irqrestore(&task->task_state_lock, flags);

	SAS_DPRINTK("command 0x%p, task 0x%p, timed out: EH_NOT_HANDLED\n",
		    cmd, task);

	return EH_NOT_HANDLED;
}

int sas_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
{
	struct domain_device *dev = sdev_to_domain_dev(sdev);

	if (dev_is_sata(dev))
		return ata_scsi_ioctl(sdev, cmd, arg);

	return -EINVAL;
}

struct domain_device *sas_find_dev_by_rphy(struct sas_rphy *rphy)
{
	struct Scsi_Host *shost = dev_to_shost(rphy->dev.parent);
	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
	struct domain_device *found_dev = NULL;
	int i;
	unsigned long flags;

	spin_lock_irqsave(&ha->phy_port_lock, flags);
	for (i = 0; i < ha->num_phys; i++) {
		struct asd_sas_port *port = ha->sas_port[i];
		struct domain_device *dev;

		spin_lock(&port->dev_list_lock);
		list_for_each_entry(dev, &port->dev_list, dev_list_node) {
			if (rphy == dev->rphy) {
				found_dev = dev;
				spin_unlock(&port->dev_list_lock);
				goto found;
			}
		}
		spin_unlock(&port->dev_list_lock);
	}
 found:
	spin_unlock_irqrestore(&ha->phy_port_lock, flags);

	return found_dev;
}

static inline struct domain_device *sas_find_target(struct scsi_target *starget)
{
	struct sas_rphy *rphy = dev_to_rphy(starget->dev.parent);

	return sas_find_dev_by_rphy(rphy);
}

int sas_target_alloc(struct scsi_target *starget)
{
	struct domain_device *found_dev = sas_find_target(starget);
	int res;

	if (!found_dev)
		return -ENODEV;

	if (dev_is_sata(found_dev)) {
		res = sas_ata_init_host_and_port(found_dev, starget);
		if (res)
			return res;
	}

	starget->hostdata = found_dev;
	return 0;
}

#define SAS_DEF_QD 32
#define SAS_MAX_QD 64

int sas_slave_configure(struct scsi_device *scsi_dev)
{
	struct domain_device *dev = sdev_to_domain_dev(scsi_dev);
	struct sas_ha_struct *sas_ha;

	BUG_ON(dev->rphy->identify.device_type != SAS_END_DEVICE);

	if (dev_is_sata(dev)) {
		ata_sas_slave_configure(scsi_dev, dev->sata_dev.ap);
		return 0;
	}

	sas_ha = dev->port->ha;

	sas_read_port_mode_page(scsi_dev);

	if (scsi_dev->tagged_supported) {
		scsi_set_tag_type(scsi_dev, MSG_SIMPLE_TAG);
		scsi_activate_tcq(scsi_dev, SAS_DEF_QD);
	} else {
		SAS_DPRINTK("device %llx, LUN %x doesn't support "
			    "TCQ\n", SAS_ADDR(dev->sas_addr),
			    scsi_dev->lun);
		scsi_dev->tagged_supported = 0;
		scsi_set_tag_type(scsi_dev, 0);
		scsi_deactivate_tcq(scsi_dev, 1);
	}

	scsi_dev->allow_restart = 1;

	return 0;
}

void sas_slave_destroy(struct scsi_device *scsi_dev)
{
	struct domain_device *dev = sdev_to_domain_dev(scsi_dev);

	if (dev_is_sata(dev))
		ata_port_disable(dev->sata_dev.ap);
}

int sas_change_queue_depth(struct scsi_device *scsi_dev, int new_depth)
{
	int res = min(new_depth, SAS_MAX_QD);

	if (scsi_dev->tagged_supported)
		scsi_adjust_queue_depth(scsi_dev, scsi_get_tag_type(scsi_dev),
					res);
	else {
		struct domain_device *dev = sdev_to_domain_dev(scsi_dev);
		sas_printk("device %llx LUN %x queue depth changed to 1\n",
			   SAS_ADDR(dev->sas_addr),
			   scsi_dev->lun);
		scsi_adjust_queue_depth(scsi_dev, 0, 1);
		res = 1;
	}

	return res;
}

int sas_change_queue_type(struct scsi_device *scsi_dev, int qt)
{
	if (!scsi_dev->tagged_supported)
		return 0;

	scsi_deactivate_tcq(scsi_dev, 1);

	scsi_set_tag_type(scsi_dev, qt);
	scsi_activate_tcq(scsi_dev, scsi_dev->queue_depth);

	return qt;
}

int sas_bios_param(struct scsi_device *scsi_dev,
			  struct block_device *bdev,
			  sector_t capacity, int *hsc)
{
	hsc[0] = 255;
	hsc[1] = 63;
	sector_div(capacity, 255*63);
	hsc[2] = capacity;

	return 0;
}

/* ---------- Task Collector Thread implementation ---------- */

static void sas_queue(struct sas_ha_struct *sas_ha)
{
	struct scsi_core *core = &sas_ha->core;
	unsigned long flags;
	LIST_HEAD(q);
	int can_queue;
	int res;
	struct sas_internal *i = to_sas_internal(core->shost->transportt);

	spin_lock_irqsave(&core->task_queue_lock, flags);
	while (!kthread_should_stop() &&
	       !list_empty(&core->task_queue)) {

		can_queue = sas_ha->lldd_queue_size - core->task_queue_size;
		if (can_queue >= 0) {
			can_queue = core->task_queue_size;
			list_splice_init(&core->task_queue, &q);
		} else {
			struct list_head *a, *n;

			can_queue = sas_ha->lldd_queue_size;
			list_for_each_safe(a, n, &core->task_queue) {
				list_move_tail(a, &q);
				if (--can_queue == 0)
					break;
			}
			can_queue = sas_ha->lldd_queue_size;
		}
		core->task_queue_size -= can_queue;
		spin_unlock_irqrestore(&core->task_queue_lock, flags);
		{
			struct sas_task *task = list_entry(q.next,
							   struct sas_task,
							   list);
			list_del_init(&q);
			res = i->dft->lldd_execute_task(task, can_queue,
							GFP_KERNEL);
			if (unlikely(res))
				__list_add(&q, task->list.prev, &task->list);
		}
		spin_lock_irqsave(&core->task_queue_lock, flags);
		if (res) {
			list_splice_init(&q, &core->task_queue); /*at head*/
			core->task_queue_size += can_queue;
		}
	}
	spin_unlock_irqrestore(&core->task_queue_lock, flags);
}

/**
 * sas_queue_thread -- The Task Collector thread
 * @_sas_ha: pointer to struct sas_ha
 */
static int sas_queue_thread(void *_sas_ha)
{
	struct sas_ha_struct *sas_ha = _sas_ha;

	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);
		schedule();
		sas_queue(sas_ha);
		if (kthread_should_stop())
			break;
	}

	return 0;
}

int sas_init_queue(struct sas_ha_struct *sas_ha)
{
	struct scsi_core *core = &sas_ha->core;

	spin_lock_init(&core->task_queue_lock);
	core->task_queue_size = 0;
	INIT_LIST_HEAD(&core->task_queue);

	core->queue_thread = kthread_run(sas_queue_thread, sas_ha,
					 "sas_queue_%d", core->shost->host_no);
	if (IS_ERR(core->queue_thread))
		return PTR_ERR(core->queue_thread);
	return 0;
}

void sas_shutdown_queue(struct sas_ha_struct *sas_ha)
{
	unsigned long flags;
	struct scsi_core *core = &sas_ha->core;
	struct sas_task *task, *n;

	kthread_stop(core->queue_thread);

	if (!list_empty(&core->task_queue))
		SAS_DPRINTK("HA: %llx: scsi core task queue is NOT empty!?\n",
			    SAS_ADDR(sas_ha->sas_addr));

	spin_lock_irqsave(&core->task_queue_lock, flags);
	list_for_each_entry_safe(task, n, &core->task_queue, list) {
		struct scsi_cmnd *cmd = task->uldd_task;

		list_del_init(&task->list);

		ASSIGN_SAS_TASK(cmd, NULL);
		sas_free_task(task);
		cmd->result = DID_ABORT << 16;
		cmd->scsi_done(cmd);
	}
	spin_unlock_irqrestore(&core->task_queue_lock, flags);
}

/*
 * Call the LLDD task abort routine directly.  This function is intended for
 * use by upper layers that need to tell the LLDD to abort a task.
 */
int __sas_task_abort(struct sas_task *task)
{
	struct sas_internal *si =
		to_sas_internal(task->dev->port->ha->core.shost->transportt);
	unsigned long flags;
	int res;

	spin_lock_irqsave(&task->task_state_lock, flags);
	if (task->task_state_flags & SAS_TASK_STATE_ABORTED ||
	    task->task_state_flags & SAS_TASK_STATE_DONE) {
		spin_unlock_irqrestore(&task->task_state_lock, flags);
		SAS_DPRINTK("%s: Task %p already finished.\n", __func__,
			    task);
		return 0;
	}
	task->task_state_flags |= SAS_TASK_STATE_ABORTED;
	spin_unlock_irqrestore(&task->task_state_lock, flags);

	if (!si->dft->lldd_abort_task)
		return -ENODEV;

	res = si->dft->lldd_abort_task(task);

	spin_lock_irqsave(&task->task_state_lock, flags);
	if ((task->task_state_flags & SAS_TASK_STATE_DONE) ||
	    (res == TMF_RESP_FUNC_COMPLETE))
	{
		spin_unlock_irqrestore(&task->task_state_lock, flags);
		task->task_done(task);
		return 0;
	}

	if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
		task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
	spin_unlock_irqrestore(&task->task_state_lock, flags);

	return -EAGAIN;
}

/*
 * Tell an upper layer that it needs to initiate an abort for a given task.
 * This should only ever be called by an LLDD.
 */
void sas_task_abort(struct sas_task *task)
{
	struct scsi_cmnd *sc = task->uldd_task;

	/* Escape for libsas internal commands */
	if (!sc) {
		if (!del_timer(&task->timer))
			return;
		task->timer.function(task->timer.data);
		return;
	}

	if (dev_is_sata(task->dev)) {
		sas_ata_task_abort(task);
		return;
	}

	scsi_req_abort_cmd(sc);
	scsi_schedule_eh(sc->device->host);
}

int sas_slave_alloc(struct scsi_device *scsi_dev)
{
	struct domain_device *dev = sdev_to_domain_dev(scsi_dev);

	if (dev_is_sata(dev))
		return ata_sas_port_init(dev->sata_dev.ap);

	return 0;
}

void sas_target_destroy(struct scsi_target *starget)
{
	struct domain_device *found_dev = sas_find_target(starget);

	if (!found_dev)
		return;

	if (dev_is_sata(found_dev))
		ata_sas_port_destroy(found_dev->sata_dev.ap);

	return;
}

static void sas_parse_addr(u8 *sas_addr, const char *p)
{
	int i;
	for (i = 0; i < SAS_ADDR_SIZE; i++) {
		u8 h, l;
		if (!*p)
			break;
		h = isdigit(*p) ? *p-'0' : toupper(*p)-'A'+10;
		p++;
		l = isdigit(*p) ? *p-'0' : toupper(*p)-'A'+10;
		p++;
		sas_addr[i] = (h<<4) | l;
	}
}

#define SAS_STRING_ADDR_SIZE	16

int sas_request_addr(struct Scsi_Host *shost, u8 *addr)
{
	int res;
	const struct firmware *fw;

	res = request_firmware(&fw, "sas_addr", &shost->shost_gendev);
	if (res)
		return res;

	if (fw->size < SAS_STRING_ADDR_SIZE) {
		res = -ENODEV;
		goto out;
	}

	sas_parse_addr(addr, fw->data);

out:
	release_firmware(fw);
	return res;
}
EXPORT_SYMBOL_GPL(sas_request_addr);

EXPORT_SYMBOL_GPL(sas_queuecommand);
EXPORT_SYMBOL_GPL(sas_target_alloc);
EXPORT_SYMBOL_GPL(sas_slave_configure);
EXPORT_SYMBOL_GPL(sas_slave_destroy);
EXPORT_SYMBOL_GPL(sas_change_queue_depth);
EXPORT_SYMBOL_GPL(sas_change_queue_type);
EXPORT_SYMBOL_GPL(sas_bios_param);
EXPORT_SYMBOL_GPL(__sas_task_abort);
EXPORT_SYMBOL_GPL(sas_task_abort);
EXPORT_SYMBOL_GPL(sas_phy_reset);
EXPORT_SYMBOL_GPL(sas_phy_enable);
EXPORT_SYMBOL_GPL(sas_eh_device_reset_handler);
EXPORT_SYMBOL_GPL(sas_eh_bus_reset_handler);
EXPORT_SYMBOL_GPL(sas_slave_alloc);
EXPORT_SYMBOL_GPL(sas_target_destroy);
EXPORT_SYMBOL_GPL(sas_ioctl);