summaryrefslogtreecommitdiff
path: root/drivers/nvme/host/multipath.c
blob: e8ccdd398f784443241d659761414f0e622c111b (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2017-2018 Christoph Hellwig.
 */

#include <linux/backing-dev.h>
#include <linux/moduleparam.h>
#include <trace/events/block.h>
#include "nvme.h"

static bool multipath = true;
module_param(multipath, bool, 0444);
MODULE_PARM_DESC(multipath,
	"turn on native support for multiple controllers per subsystem");

void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
{
	struct nvme_ns_head *h;

	lockdep_assert_held(&subsys->lock);
	list_for_each_entry(h, &subsys->nsheads, entry)
		if (h->disk)
			blk_mq_unfreeze_queue(h->disk->queue);
}

void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
{
	struct nvme_ns_head *h;

	lockdep_assert_held(&subsys->lock);
	list_for_each_entry(h, &subsys->nsheads, entry)
		if (h->disk)
			blk_mq_freeze_queue_wait(h->disk->queue);
}

void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
{
	struct nvme_ns_head *h;

	lockdep_assert_held(&subsys->lock);
	list_for_each_entry(h, &subsys->nsheads, entry)
		if (h->disk)
			blk_freeze_queue_start(h->disk->queue);
}

/*
 * If multipathing is enabled we need to always use the subsystem instance
 * number for numbering our devices to avoid conflicts between subsystems that
 * have multiple controllers and thus use the multipath-aware subsystem node
 * and those that have a single controller and use the controller node
 * directly.
 */
bool nvme_mpath_set_disk_name(struct nvme_ns *ns, char *disk_name, int *flags)
{
	if (!multipath)
		return false;
	if (!ns->head->disk) {
		sprintf(disk_name, "nvme%dn%d", ns->ctrl->subsys->instance,
			ns->head->instance);
		return true;
	}
	sprintf(disk_name, "nvme%dc%dn%d", ns->ctrl->subsys->instance,
		ns->ctrl->instance, ns->head->instance);
	*flags = GENHD_FL_HIDDEN;
	return true;
}

void nvme_failover_req(struct request *req)
{
	struct nvme_ns *ns = req->q->queuedata;
	u16 status = nvme_req(req)->status & 0x7ff;
	unsigned long flags;
	struct bio *bio;

	nvme_mpath_clear_current_path(ns);

	/*
	 * If we got back an ANA error, we know the controller is alive but not
	 * ready to serve this namespace.  Kick of a re-read of the ANA
	 * information page, and just try any other available path for now.
	 */
	if (nvme_is_ana_error(status) && ns->ctrl->ana_log_buf) {
		set_bit(NVME_NS_ANA_PENDING, &ns->flags);
		queue_work(nvme_wq, &ns->ctrl->ana_work);
	}

	spin_lock_irqsave(&ns->head->requeue_lock, flags);
	for (bio = req->bio; bio; bio = bio->bi_next)
		bio_set_dev(bio, ns->head->disk->part0);
	blk_steal_bios(&ns->head->requeue_list, req);
	spin_unlock_irqrestore(&ns->head->requeue_lock, flags);

	blk_mq_end_request(req, 0);
	kblockd_schedule_work(&ns->head->requeue_work);
}

void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	down_read(&ctrl->namespaces_rwsem);
	list_for_each_entry(ns, &ctrl->namespaces, list) {
		if (ns->head->disk)
			kblockd_schedule_work(&ns->head->requeue_work);
	}
	up_read(&ctrl->namespaces_rwsem);
}

static const char *nvme_ana_state_names[] = {
	[0]				= "invalid state",
	[NVME_ANA_OPTIMIZED]		= "optimized",
	[NVME_ANA_NONOPTIMIZED]		= "non-optimized",
	[NVME_ANA_INACCESSIBLE]		= "inaccessible",
	[NVME_ANA_PERSISTENT_LOSS]	= "persistent-loss",
	[NVME_ANA_CHANGE]		= "change",
};

bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
{
	struct nvme_ns_head *head = ns->head;
	bool changed = false;
	int node;

	if (!head)
		goto out;

	for_each_node(node) {
		if (ns == rcu_access_pointer(head->current_path[node])) {
			rcu_assign_pointer(head->current_path[node], NULL);
			changed = true;
		}
	}
out:
	return changed;
}

void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
{
	struct nvme_ns *ns;

	mutex_lock(&ctrl->scan_lock);
	down_read(&ctrl->namespaces_rwsem);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		if (nvme_mpath_clear_current_path(ns))
			kblockd_schedule_work(&ns->head->requeue_work);
	up_read(&ctrl->namespaces_rwsem);
	mutex_unlock(&ctrl->scan_lock);
}

void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
{
	struct nvme_ns_head *head = ns->head;
	sector_t capacity = get_capacity(head->disk);
	int node;

	list_for_each_entry_rcu(ns, &head->list, siblings) {
		if (capacity != get_capacity(ns->disk))
			clear_bit(NVME_NS_READY, &ns->flags);
	}

	for_each_node(node)
		rcu_assign_pointer(head->current_path[node], NULL);
}

static bool nvme_path_is_disabled(struct nvme_ns *ns)
{
	/*
	 * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should
	 * still be able to complete assuming that the controller is connected.
	 * Otherwise it will fail immediately and return to the requeue list.
	 */
	if (ns->ctrl->state != NVME_CTRL_LIVE &&
	    ns->ctrl->state != NVME_CTRL_DELETING)
		return true;
	if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
	    !test_bit(NVME_NS_READY, &ns->flags))
		return true;
	return false;
}

static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
{
	int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
	struct nvme_ns *found = NULL, *fallback = NULL, *ns;

	list_for_each_entry_rcu(ns, &head->list, siblings) {
		if (nvme_path_is_disabled(ns))
			continue;

		if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
			distance = node_distance(node, ns->ctrl->numa_node);
		else
			distance = LOCAL_DISTANCE;

		switch (ns->ana_state) {
		case NVME_ANA_OPTIMIZED:
			if (distance < found_distance) {
				found_distance = distance;
				found = ns;
			}
			break;
		case NVME_ANA_NONOPTIMIZED:
			if (distance < fallback_distance) {
				fallback_distance = distance;
				fallback = ns;
			}
			break;
		default:
			break;
		}
	}

	if (!found)
		found = fallback;
	if (found)
		rcu_assign_pointer(head->current_path[node], found);
	return found;
}

static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
		struct nvme_ns *ns)
{
	ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
			siblings);
	if (ns)
		return ns;
	return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
}

static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
		int node, struct nvme_ns *old)
{
	struct nvme_ns *ns, *found = NULL;

	if (list_is_singular(&head->list)) {
		if (nvme_path_is_disabled(old))
			return NULL;
		return old;
	}

	for (ns = nvme_next_ns(head, old);
	     ns && ns != old;
	     ns = nvme_next_ns(head, ns)) {
		if (nvme_path_is_disabled(ns))
			continue;

		if (ns->ana_state == NVME_ANA_OPTIMIZED) {
			found = ns;
			goto out;
		}
		if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
			found = ns;
	}

	/*
	 * The loop above skips the current path for round-robin semantics.
	 * Fall back to the current path if either:
	 *  - no other optimized path found and current is optimized,
	 *  - no other usable path found and current is usable.
	 */
	if (!nvme_path_is_disabled(old) &&
	    (old->ana_state == NVME_ANA_OPTIMIZED ||
	     (!found && old->ana_state == NVME_ANA_NONOPTIMIZED)))
		return old;

	if (!found)
		return NULL;
out:
	rcu_assign_pointer(head->current_path[node], found);
	return found;
}

static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
{
	return ns->ctrl->state == NVME_CTRL_LIVE &&
		ns->ana_state == NVME_ANA_OPTIMIZED;
}

inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
{
	int node = numa_node_id();
	struct nvme_ns *ns;

	ns = srcu_dereference(head->current_path[node], &head->srcu);
	if (unlikely(!ns))
		return __nvme_find_path(head, node);

	if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
		return nvme_round_robin_path(head, node, ns);
	if (unlikely(!nvme_path_is_optimized(ns)))
		return __nvme_find_path(head, node);
	return ns;
}

static bool nvme_available_path(struct nvme_ns_head *head)
{
	struct nvme_ns *ns;

	list_for_each_entry_rcu(ns, &head->list, siblings) {
		if (test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ns->ctrl->flags))
			continue;
		switch (ns->ctrl->state) {
		case NVME_CTRL_LIVE:
		case NVME_CTRL_RESETTING:
		case NVME_CTRL_CONNECTING:
			/* fallthru */
			return true;
		default:
			break;
		}
	}
	return false;
}

static blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
{
	struct nvme_ns_head *head = bio->bi_bdev->bd_disk->private_data;
	struct device *dev = disk_to_dev(head->disk);
	struct nvme_ns *ns;
	blk_qc_t ret = BLK_QC_T_NONE;
	int srcu_idx;

	/*
	 * The namespace might be going away and the bio might be moved to a
	 * different queue via blk_steal_bios(), so we need to use the bio_split
	 * pool from the original queue to allocate the bvecs from.
	 */
	blk_queue_split(&bio);

	srcu_idx = srcu_read_lock(&head->srcu);
	ns = nvme_find_path(head);
	if (likely(ns)) {
		bio_set_dev(bio, ns->disk->part0);
		bio->bi_opf |= REQ_NVME_MPATH;
		trace_block_bio_remap(bio, disk_devt(ns->head->disk),
				      bio->bi_iter.bi_sector);
		ret = submit_bio_noacct(bio);
	} else if (nvme_available_path(head)) {
		dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");

		spin_lock_irq(&head->requeue_lock);
		bio_list_add(&head->requeue_list, bio);
		spin_unlock_irq(&head->requeue_lock);
	} else {
		dev_warn_ratelimited(dev, "no available path - failing I/O\n");

		bio->bi_status = BLK_STS_IOERR;
		bio_endio(bio);
	}

	srcu_read_unlock(&head->srcu, srcu_idx);
	return ret;
}

static int nvme_ns_head_open(struct block_device *bdev, fmode_t mode)
{
	if (!nvme_tryget_ns_head(bdev->bd_disk->private_data))
		return -ENXIO;
	return 0;
}

static void nvme_ns_head_release(struct gendisk *disk, fmode_t mode)
{
	nvme_put_ns_head(disk->private_data);
}

#ifdef CONFIG_BLK_DEV_ZONED
static int nvme_ns_head_report_zones(struct gendisk *disk, sector_t sector,
		unsigned int nr_zones, report_zones_cb cb, void *data)
{
	struct nvme_ns_head *head = disk->private_data;
	struct nvme_ns *ns;
	int srcu_idx, ret = -EWOULDBLOCK;

	srcu_idx = srcu_read_lock(&head->srcu);
	ns = nvme_find_path(head);
	if (ns)
		ret = nvme_ns_report_zones(ns, sector, nr_zones, cb, data);
	srcu_read_unlock(&head->srcu, srcu_idx);
	return ret;
}
#else
#define nvme_ns_head_report_zones	NULL
#endif /* CONFIG_BLK_DEV_ZONED */

const struct block_device_operations nvme_ns_head_ops = {
	.owner		= THIS_MODULE,
	.submit_bio	= nvme_ns_head_submit_bio,
	.open		= nvme_ns_head_open,
	.release	= nvme_ns_head_release,
	.ioctl		= nvme_ns_head_ioctl,
	.getgeo		= nvme_getgeo,
	.report_zones	= nvme_ns_head_report_zones,
	.pr_ops		= &nvme_pr_ops,
};

static inline struct nvme_ns_head *cdev_to_ns_head(struct cdev *cdev)
{
	return container_of(cdev, struct nvme_ns_head, cdev);
}

static int nvme_ns_head_chr_open(struct inode *inode, struct file *file)
{
	if (!nvme_tryget_ns_head(cdev_to_ns_head(inode->i_cdev)))
		return -ENXIO;
	return 0;
}

static int nvme_ns_head_chr_release(struct inode *inode, struct file *file)
{
	nvme_put_ns_head(cdev_to_ns_head(inode->i_cdev));
	return 0;
}

static const struct file_operations nvme_ns_head_chr_fops = {
	.owner		= THIS_MODULE,
	.open		= nvme_ns_head_chr_open,
	.release	= nvme_ns_head_chr_release,
	.unlocked_ioctl	= nvme_ns_head_chr_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
};

static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
{
	int ret;

	head->cdev_device.parent = &head->subsys->dev;
	ret = dev_set_name(&head->cdev_device, "ng%dn%d",
			   head->subsys->instance, head->instance);
	if (ret)
		return ret;
	ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
			    &nvme_ns_head_chr_fops, THIS_MODULE);
	if (ret)
		kfree_const(head->cdev_device.kobj.name);
	return ret;
}

static void nvme_requeue_work(struct work_struct *work)
{
	struct nvme_ns_head *head =
		container_of(work, struct nvme_ns_head, requeue_work);
	struct bio *bio, *next;

	spin_lock_irq(&head->requeue_lock);
	next = bio_list_get(&head->requeue_list);
	spin_unlock_irq(&head->requeue_lock);

	while ((bio = next) != NULL) {
		next = bio->bi_next;
		bio->bi_next = NULL;

		submit_bio_noacct(bio);
	}
}

int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
{
	bool vwc = false;

	mutex_init(&head->lock);
	bio_list_init(&head->requeue_list);
	spin_lock_init(&head->requeue_lock);
	INIT_WORK(&head->requeue_work, nvme_requeue_work);

	/*
	 * Add a multipath node if the subsystems supports multiple controllers.
	 * We also do this for private namespaces as the namespace sharing data could
	 * change after a rescan.
	 */
	if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) || !multipath)
		return 0;

	head->disk = blk_alloc_disk(ctrl->numa_node);
	if (!head->disk)
		return -ENOMEM;
	head->disk->fops = &nvme_ns_head_ops;
	head->disk->private_data = head;
	sprintf(head->disk->disk_name, "nvme%dn%d",
			ctrl->subsys->instance, head->instance);

	blk_queue_flag_set(QUEUE_FLAG_NONROT, head->disk->queue);
	blk_queue_flag_set(QUEUE_FLAG_NOWAIT, head->disk->queue);

	/* set to a default value of 512 until the disk is validated */
	blk_queue_logical_block_size(head->disk->queue, 512);
	blk_set_stacking_limits(&head->disk->queue->limits);

	/* we need to propagate up the VMC settings */
	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
		vwc = true;
	blk_queue_write_cache(head->disk->queue, vwc, vwc);
	return 0;
}

static void nvme_mpath_set_live(struct nvme_ns *ns)
{
	struct nvme_ns_head *head = ns->head;

	if (!head->disk)
		return;

	if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
		device_add_disk(&head->subsys->dev, head->disk,
				nvme_ns_id_attr_groups);
		nvme_add_ns_head_cdev(head);
	}

	mutex_lock(&head->lock);
	if (nvme_path_is_optimized(ns)) {
		int node, srcu_idx;

		srcu_idx = srcu_read_lock(&head->srcu);
		for_each_node(node)
			__nvme_find_path(head, node);
		srcu_read_unlock(&head->srcu, srcu_idx);
	}
	mutex_unlock(&head->lock);

	synchronize_srcu(&head->srcu);
	kblockd_schedule_work(&head->requeue_work);
}

static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
		int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
			void *))
{
	void *base = ctrl->ana_log_buf;
	size_t offset = sizeof(struct nvme_ana_rsp_hdr);
	int error, i;

	lockdep_assert_held(&ctrl->ana_lock);

	for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
		struct nvme_ana_group_desc *desc = base + offset;
		u32 nr_nsids;
		size_t nsid_buf_size;

		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
			return -EINVAL;

		nr_nsids = le32_to_cpu(desc->nnsids);
		nsid_buf_size = nr_nsids * sizeof(__le32);

		if (WARN_ON_ONCE(desc->grpid == 0))
			return -EINVAL;
		if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
			return -EINVAL;
		if (WARN_ON_ONCE(desc->state == 0))
			return -EINVAL;
		if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
			return -EINVAL;

		offset += sizeof(*desc);
		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
			return -EINVAL;

		error = cb(ctrl, desc, data);
		if (error)
			return error;

		offset += nsid_buf_size;
	}

	return 0;
}

static inline bool nvme_state_is_live(enum nvme_ana_state state)
{
	return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
}

static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
		struct nvme_ns *ns)
{
	ns->ana_grpid = le32_to_cpu(desc->grpid);
	ns->ana_state = desc->state;
	clear_bit(NVME_NS_ANA_PENDING, &ns->flags);

	if (nvme_state_is_live(ns->ana_state))
		nvme_mpath_set_live(ns);
}

static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
		struct nvme_ana_group_desc *desc, void *data)
{
	u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
	unsigned *nr_change_groups = data;
	struct nvme_ns *ns;

	dev_dbg(ctrl->device, "ANA group %d: %s.\n",
			le32_to_cpu(desc->grpid),
			nvme_ana_state_names[desc->state]);

	if (desc->state == NVME_ANA_CHANGE)
		(*nr_change_groups)++;

	if (!nr_nsids)
		return 0;

	down_read(&ctrl->namespaces_rwsem);
	list_for_each_entry(ns, &ctrl->namespaces, list) {
		unsigned nsid;
again:
		nsid = le32_to_cpu(desc->nsids[n]);
		if (ns->head->ns_id < nsid)
			continue;
		if (ns->head->ns_id == nsid)
			nvme_update_ns_ana_state(desc, ns);
		if (++n == nr_nsids)
			break;
		if (ns->head->ns_id > nsid)
			goto again;
	}
	up_read(&ctrl->namespaces_rwsem);
	return 0;
}

static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
{
	u32 nr_change_groups = 0;
	int error;

	mutex_lock(&ctrl->ana_lock);
	error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0, NVME_CSI_NVM,
			ctrl->ana_log_buf, ctrl->ana_log_size, 0);
	if (error) {
		dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
		goto out_unlock;
	}

	error = nvme_parse_ana_log(ctrl, &nr_change_groups,
			nvme_update_ana_state);
	if (error)
		goto out_unlock;

	/*
	 * In theory we should have an ANATT timer per group as they might enter
	 * the change state at different times.  But that is a lot of overhead
	 * just to protect against a target that keeps entering new changes
	 * states while never finishing previous ones.  But we'll still
	 * eventually time out once all groups are in change state, so this
	 * isn't a big deal.
	 *
	 * We also double the ANATT value to provide some slack for transports
	 * or AEN processing overhead.
	 */
	if (nr_change_groups)
		mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
	else
		del_timer_sync(&ctrl->anatt_timer);
out_unlock:
	mutex_unlock(&ctrl->ana_lock);
	return error;
}

static void nvme_ana_work(struct work_struct *work)
{
	struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);

	if (ctrl->state != NVME_CTRL_LIVE)
		return;

	nvme_read_ana_log(ctrl);
}

static void nvme_anatt_timeout(struct timer_list *t)
{
	struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);

	dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
	nvme_reset_ctrl(ctrl);
}

void nvme_mpath_stop(struct nvme_ctrl *ctrl)
{
	if (!nvme_ctrl_use_ana(ctrl))
		return;
	del_timer_sync(&ctrl->anatt_timer);
	cancel_work_sync(&ctrl->ana_work);
}

#define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
	struct device_attribute subsys_attr_##_name =	\
		__ATTR(_name, _mode, _show, _store)

static const char *nvme_iopolicy_names[] = {
	[NVME_IOPOLICY_NUMA]	= "numa",
	[NVME_IOPOLICY_RR]	= "round-robin",
};

static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct nvme_subsystem *subsys =
		container_of(dev, struct nvme_subsystem, dev);

	return sysfs_emit(buf, "%s\n",
			  nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
}

static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct nvme_subsystem *subsys =
		container_of(dev, struct nvme_subsystem, dev);
	int i;

	for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
		if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
			WRITE_ONCE(subsys->iopolicy, i);
			return count;
		}
	}

	return -EINVAL;
}
SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
		      nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);

static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	return sysfs_emit(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
}
DEVICE_ATTR_RO(ana_grpid);

static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct nvme_ns *ns = nvme_get_ns_from_dev(dev);

	return sysfs_emit(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
}
DEVICE_ATTR_RO(ana_state);

static int nvme_lookup_ana_group_desc(struct nvme_ctrl *ctrl,
		struct nvme_ana_group_desc *desc, void *data)
{
	struct nvme_ana_group_desc *dst = data;

	if (desc->grpid != dst->grpid)
		return 0;

	*dst = *desc;
	return -ENXIO; /* just break out of the loop */
}

void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
{
	if (nvme_ctrl_use_ana(ns->ctrl)) {
		struct nvme_ana_group_desc desc = {
			.grpid = id->anagrpid,
			.state = 0,
		};

		mutex_lock(&ns->ctrl->ana_lock);
		ns->ana_grpid = le32_to_cpu(id->anagrpid);
		nvme_parse_ana_log(ns->ctrl, &desc, nvme_lookup_ana_group_desc);
		mutex_unlock(&ns->ctrl->ana_lock);
		if (desc.state) {
			/* found the group desc: update */
			nvme_update_ns_ana_state(&desc, ns);
		} else {
			/* group desc not found: trigger a re-read */
			set_bit(NVME_NS_ANA_PENDING, &ns->flags);
			queue_work(nvme_wq, &ns->ctrl->ana_work);
		}
	} else {
		ns->ana_state = NVME_ANA_OPTIMIZED;
		nvme_mpath_set_live(ns);
	}

	if (blk_queue_stable_writes(ns->queue) && ns->head->disk)
		blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
				   ns->head->disk->queue);
#ifdef CONFIG_BLK_DEV_ZONED
	if (blk_queue_is_zoned(ns->queue) && ns->head->disk)
		ns->head->disk->queue->nr_zones = ns->queue->nr_zones;
#endif
}

void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)
{
	if (!head->disk)
		return;
	kblockd_schedule_work(&head->requeue_work);
	if (test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
		nvme_cdev_del(&head->cdev, &head->cdev_device);
		del_gendisk(head->disk);
	}
}

void nvme_mpath_remove_disk(struct nvme_ns_head *head)
{
	if (!head->disk)
		return;
	blk_set_queue_dying(head->disk->queue);
	/* make sure all pending bios are cleaned up */
	kblockd_schedule_work(&head->requeue_work);
	flush_work(&head->requeue_work);
	blk_cleanup_disk(head->disk);
}

void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl)
{
	mutex_init(&ctrl->ana_lock);
	timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
	INIT_WORK(&ctrl->ana_work, nvme_ana_work);
}

int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
{
	size_t max_transfer_size = ctrl->max_hw_sectors << SECTOR_SHIFT;
	size_t ana_log_size;
	int error = 0;

	/* check if multipath is enabled and we have the capability */
	if (!multipath || !ctrl->subsys ||
	    !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
		return 0;

	if (!ctrl->max_namespaces ||
	    ctrl->max_namespaces > le32_to_cpu(id->nn)) {
		dev_err(ctrl->device,
			"Invalid MNAN value %u\n", ctrl->max_namespaces);
		return -EINVAL;
	}

	ctrl->anacap = id->anacap;
	ctrl->anatt = id->anatt;
	ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
	ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);

	ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
		ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc) +
		ctrl->max_namespaces * sizeof(__le32);
	if (ana_log_size > max_transfer_size) {
		dev_err(ctrl->device,
			"ANA log page size (%zd) larger than MDTS (%zd).\n",
			ana_log_size, max_transfer_size);
		dev_err(ctrl->device, "disabling ANA support.\n");
		goto out_uninit;
	}
	if (ana_log_size > ctrl->ana_log_size) {
		nvme_mpath_stop(ctrl);
		kfree(ctrl->ana_log_buf);
		ctrl->ana_log_buf = kmalloc(ana_log_size, GFP_KERNEL);
		if (!ctrl->ana_log_buf)
			return -ENOMEM;
	}
	ctrl->ana_log_size = ana_log_size;
	error = nvme_read_ana_log(ctrl);
	if (error)
		goto out_uninit;
	return 0;

out_uninit:
	nvme_mpath_uninit(ctrl);
	return error;
}

void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
{
	kfree(ctrl->ana_log_buf);
	ctrl->ana_log_buf = NULL;
}