xref: /openbmc/linux/drivers/nvme/host/multipath.c (revision 4d66c56f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2017-2018 Christoph Hellwig.
4  */
5 
6 #include <linux/moduleparam.h>
7 #include <trace/events/block.h>
8 #include "nvme.h"
9 
10 static bool multipath = true;
11 module_param(multipath, bool, 0444);
12 MODULE_PARM_DESC(multipath,
13 	"turn on native support for multiple controllers per subsystem");
14 
15 void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
16 {
17 	struct nvme_ns_head *h;
18 
19 	lockdep_assert_held(&subsys->lock);
20 	list_for_each_entry(h, &subsys->nsheads, entry)
21 		if (h->disk)
22 			blk_mq_unfreeze_queue(h->disk->queue);
23 }
24 
25 void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
26 {
27 	struct nvme_ns_head *h;
28 
29 	lockdep_assert_held(&subsys->lock);
30 	list_for_each_entry(h, &subsys->nsheads, entry)
31 		if (h->disk)
32 			blk_mq_freeze_queue_wait(h->disk->queue);
33 }
34 
35 void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
36 {
37 	struct nvme_ns_head *h;
38 
39 	lockdep_assert_held(&subsys->lock);
40 	list_for_each_entry(h, &subsys->nsheads, entry)
41 		if (h->disk)
42 			blk_freeze_queue_start(h->disk->queue);
43 }
44 
45 /*
46  * If multipathing is enabled we need to always use the subsystem instance
47  * number for numbering our devices to avoid conflicts between subsystems that
48  * have multiple controllers and thus use the multipath-aware subsystem node
49  * and those that have a single controller and use the controller node
50  * directly.
51  */
52 void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
53 			struct nvme_ctrl *ctrl, int *flags)
54 {
55 	if (!multipath) {
56 		sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
57 	} else if (ns->head->disk) {
58 		sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
59 				ctrl->instance, ns->head->instance);
60 		*flags = GENHD_FL_HIDDEN;
61 	} else {
62 		sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
63 				ns->head->instance);
64 	}
65 }
66 
67 void nvme_failover_req(struct request *req)
68 {
69 	struct nvme_ns *ns = req->q->queuedata;
70 	u16 status = nvme_req(req)->status;
71 	unsigned long flags;
72 
73 	spin_lock_irqsave(&ns->head->requeue_lock, flags);
74 	blk_steal_bios(&ns->head->requeue_list, req);
75 	spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
76 	blk_mq_end_request(req, 0);
77 
78 	switch (status & 0x7ff) {
79 	case NVME_SC_ANA_TRANSITION:
80 	case NVME_SC_ANA_INACCESSIBLE:
81 	case NVME_SC_ANA_PERSISTENT_LOSS:
82 		/*
83 		 * If we got back an ANA error we know the controller is alive,
84 		 * but not ready to serve this namespaces.  The spec suggests
85 		 * we should update our general state here, but due to the fact
86 		 * that the admin and I/O queues are not serialized that is
87 		 * fundamentally racy.  So instead just clear the current path,
88 		 * mark the the path as pending and kick of a re-read of the ANA
89 		 * log page ASAP.
90 		 */
91 		nvme_mpath_clear_current_path(ns);
92 		if (ns->ctrl->ana_log_buf) {
93 			set_bit(NVME_NS_ANA_PENDING, &ns->flags);
94 			queue_work(nvme_wq, &ns->ctrl->ana_work);
95 		}
96 		break;
97 	case NVME_SC_HOST_PATH_ERROR:
98 		/*
99 		 * Temporary transport disruption in talking to the controller.
100 		 * Try to send on a new path.
101 		 */
102 		nvme_mpath_clear_current_path(ns);
103 		break;
104 	default:
105 		/*
106 		 * Reset the controller for any non-ANA error as we don't know
107 		 * what caused the error.
108 		 */
109 		nvme_reset_ctrl(ns->ctrl);
110 		break;
111 	}
112 
113 	kblockd_schedule_work(&ns->head->requeue_work);
114 }
115 
116 void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
117 {
118 	struct nvme_ns *ns;
119 
120 	down_read(&ctrl->namespaces_rwsem);
121 	list_for_each_entry(ns, &ctrl->namespaces, list) {
122 		if (ns->head->disk)
123 			kblockd_schedule_work(&ns->head->requeue_work);
124 	}
125 	up_read(&ctrl->namespaces_rwsem);
126 }
127 
128 static const char *nvme_ana_state_names[] = {
129 	[0]				= "invalid state",
130 	[NVME_ANA_OPTIMIZED]		= "optimized",
131 	[NVME_ANA_NONOPTIMIZED]		= "non-optimized",
132 	[NVME_ANA_INACCESSIBLE]		= "inaccessible",
133 	[NVME_ANA_PERSISTENT_LOSS]	= "persistent-loss",
134 	[NVME_ANA_CHANGE]		= "change",
135 };
136 
137 bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
138 {
139 	struct nvme_ns_head *head = ns->head;
140 	bool changed = false;
141 	int node;
142 
143 	if (!head)
144 		goto out;
145 
146 	for_each_node(node) {
147 		if (ns == rcu_access_pointer(head->current_path[node])) {
148 			rcu_assign_pointer(head->current_path[node], NULL);
149 			changed = true;
150 		}
151 	}
152 out:
153 	return changed;
154 }
155 
156 void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
157 {
158 	struct nvme_ns *ns;
159 
160 	mutex_lock(&ctrl->scan_lock);
161 	down_read(&ctrl->namespaces_rwsem);
162 	list_for_each_entry(ns, &ctrl->namespaces, list)
163 		if (nvme_mpath_clear_current_path(ns))
164 			kblockd_schedule_work(&ns->head->requeue_work);
165 	up_read(&ctrl->namespaces_rwsem);
166 	mutex_unlock(&ctrl->scan_lock);
167 }
168 
169 static bool nvme_path_is_disabled(struct nvme_ns *ns)
170 {
171 	return ns->ctrl->state != NVME_CTRL_LIVE ||
172 		test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
173 		test_bit(NVME_NS_REMOVING, &ns->flags);
174 }
175 
176 static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
177 {
178 	int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
179 	struct nvme_ns *found = NULL, *fallback = NULL, *ns;
180 
181 	list_for_each_entry_rcu(ns, &head->list, siblings) {
182 		if (nvme_path_is_disabled(ns))
183 			continue;
184 
185 		if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
186 			distance = node_distance(node, ns->ctrl->numa_node);
187 		else
188 			distance = LOCAL_DISTANCE;
189 
190 		switch (ns->ana_state) {
191 		case NVME_ANA_OPTIMIZED:
192 			if (distance < found_distance) {
193 				found_distance = distance;
194 				found = ns;
195 			}
196 			break;
197 		case NVME_ANA_NONOPTIMIZED:
198 			if (distance < fallback_distance) {
199 				fallback_distance = distance;
200 				fallback = ns;
201 			}
202 			break;
203 		default:
204 			break;
205 		}
206 	}
207 
208 	if (!found)
209 		found = fallback;
210 	if (found)
211 		rcu_assign_pointer(head->current_path[node], found);
212 	return found;
213 }
214 
215 static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
216 		struct nvme_ns *ns)
217 {
218 	ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
219 			siblings);
220 	if (ns)
221 		return ns;
222 	return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
223 }
224 
225 static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
226 		int node, struct nvme_ns *old)
227 {
228 	struct nvme_ns *ns, *found, *fallback = NULL;
229 
230 	if (list_is_singular(&head->list)) {
231 		if (nvme_path_is_disabled(old))
232 			return NULL;
233 		return old;
234 	}
235 
236 	for (ns = nvme_next_ns(head, old);
237 	     ns != old;
238 	     ns = nvme_next_ns(head, ns)) {
239 		if (nvme_path_is_disabled(ns))
240 			continue;
241 
242 		if (ns->ana_state == NVME_ANA_OPTIMIZED) {
243 			found = ns;
244 			goto out;
245 		}
246 		if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
247 			fallback = ns;
248 	}
249 
250 	if (!fallback)
251 		return NULL;
252 	found = fallback;
253 out:
254 	rcu_assign_pointer(head->current_path[node], found);
255 	return found;
256 }
257 
258 static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
259 {
260 	return ns->ctrl->state == NVME_CTRL_LIVE &&
261 		ns->ana_state == NVME_ANA_OPTIMIZED;
262 }
263 
264 inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
265 {
266 	int node = numa_node_id();
267 	struct nvme_ns *ns;
268 
269 	ns = srcu_dereference(head->current_path[node], &head->srcu);
270 	if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR && ns)
271 		ns = nvme_round_robin_path(head, node, ns);
272 	if (unlikely(!ns || !nvme_path_is_optimized(ns)))
273 		ns = __nvme_find_path(head, node);
274 	return ns;
275 }
276 
277 static bool nvme_available_path(struct nvme_ns_head *head)
278 {
279 	struct nvme_ns *ns;
280 
281 	list_for_each_entry_rcu(ns, &head->list, siblings) {
282 		switch (ns->ctrl->state) {
283 		case NVME_CTRL_LIVE:
284 		case NVME_CTRL_RESETTING:
285 		case NVME_CTRL_CONNECTING:
286 			/* fallthru */
287 			return true;
288 		default:
289 			break;
290 		}
291 	}
292 	return false;
293 }
294 
295 static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
296 		struct bio *bio)
297 {
298 	struct nvme_ns_head *head = q->queuedata;
299 	struct device *dev = disk_to_dev(head->disk);
300 	struct nvme_ns *ns;
301 	blk_qc_t ret = BLK_QC_T_NONE;
302 	int srcu_idx;
303 
304 	/*
305 	 * The namespace might be going away and the bio might
306 	 * be moved to a different queue via blk_steal_bios(),
307 	 * so we need to use the bio_split pool from the original
308 	 * queue to allocate the bvecs from.
309 	 */
310 	blk_queue_split(q, &bio);
311 
312 	srcu_idx = srcu_read_lock(&head->srcu);
313 	ns = nvme_find_path(head);
314 	if (likely(ns)) {
315 		bio->bi_disk = ns->disk;
316 		bio->bi_opf |= REQ_NVME_MPATH;
317 		trace_block_bio_remap(bio->bi_disk->queue, bio,
318 				      disk_devt(ns->head->disk),
319 				      bio->bi_iter.bi_sector);
320 		ret = direct_make_request(bio);
321 	} else if (nvme_available_path(head)) {
322 		dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
323 
324 		spin_lock_irq(&head->requeue_lock);
325 		bio_list_add(&head->requeue_list, bio);
326 		spin_unlock_irq(&head->requeue_lock);
327 	} else {
328 		dev_warn_ratelimited(dev, "no available path - failing I/O\n");
329 
330 		bio->bi_status = BLK_STS_IOERR;
331 		bio_endio(bio);
332 	}
333 
334 	srcu_read_unlock(&head->srcu, srcu_idx);
335 	return ret;
336 }
337 
338 static void nvme_requeue_work(struct work_struct *work)
339 {
340 	struct nvme_ns_head *head =
341 		container_of(work, struct nvme_ns_head, requeue_work);
342 	struct bio *bio, *next;
343 
344 	spin_lock_irq(&head->requeue_lock);
345 	next = bio_list_get(&head->requeue_list);
346 	spin_unlock_irq(&head->requeue_lock);
347 
348 	while ((bio = next) != NULL) {
349 		next = bio->bi_next;
350 		bio->bi_next = NULL;
351 
352 		/*
353 		 * Reset disk to the mpath node and resubmit to select a new
354 		 * path.
355 		 */
356 		bio->bi_disk = head->disk;
357 		generic_make_request(bio);
358 	}
359 }
360 
361 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
362 {
363 	struct request_queue *q;
364 	bool vwc = false;
365 
366 	mutex_init(&head->lock);
367 	bio_list_init(&head->requeue_list);
368 	spin_lock_init(&head->requeue_lock);
369 	INIT_WORK(&head->requeue_work, nvme_requeue_work);
370 
371 	/*
372 	 * Add a multipath node if the subsystems supports multiple controllers.
373 	 * We also do this for private namespaces as the namespace sharing data could
374 	 * change after a rescan.
375 	 */
376 	if (!(ctrl->subsys->cmic & (1 << 1)) || !multipath)
377 		return 0;
378 
379 	q = blk_alloc_queue_node(GFP_KERNEL, ctrl->numa_node);
380 	if (!q)
381 		goto out;
382 	q->queuedata = head;
383 	blk_queue_make_request(q, nvme_ns_head_make_request);
384 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
385 	/* set to a default value for 512 until disk is validated */
386 	blk_queue_logical_block_size(q, 512);
387 	blk_set_stacking_limits(&q->limits);
388 
389 	/* we need to propagate up the VMC settings */
390 	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
391 		vwc = true;
392 	blk_queue_write_cache(q, vwc, vwc);
393 
394 	head->disk = alloc_disk(0);
395 	if (!head->disk)
396 		goto out_cleanup_queue;
397 	head->disk->fops = &nvme_ns_head_ops;
398 	head->disk->private_data = head;
399 	head->disk->queue = q;
400 	head->disk->flags = GENHD_FL_EXT_DEVT;
401 	sprintf(head->disk->disk_name, "nvme%dn%d",
402 			ctrl->subsys->instance, head->instance);
403 	return 0;
404 
405 out_cleanup_queue:
406 	blk_cleanup_queue(q);
407 out:
408 	return -ENOMEM;
409 }
410 
411 static void nvme_mpath_set_live(struct nvme_ns *ns)
412 {
413 	struct nvme_ns_head *head = ns->head;
414 
415 	lockdep_assert_held(&ns->head->lock);
416 
417 	if (!head->disk)
418 		return;
419 
420 	if (!(head->disk->flags & GENHD_FL_UP))
421 		device_add_disk(&head->subsys->dev, head->disk,
422 				nvme_ns_id_attr_groups);
423 
424 	if (nvme_path_is_optimized(ns)) {
425 		int node, srcu_idx;
426 
427 		srcu_idx = srcu_read_lock(&head->srcu);
428 		for_each_node(node)
429 			__nvme_find_path(head, node);
430 		srcu_read_unlock(&head->srcu, srcu_idx);
431 	}
432 
433 	synchronize_srcu(&ns->head->srcu);
434 	kblockd_schedule_work(&ns->head->requeue_work);
435 }
436 
437 static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
438 		int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
439 			void *))
440 {
441 	void *base = ctrl->ana_log_buf;
442 	size_t offset = sizeof(struct nvme_ana_rsp_hdr);
443 	int error, i;
444 
445 	lockdep_assert_held(&ctrl->ana_lock);
446 
447 	for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
448 		struct nvme_ana_group_desc *desc = base + offset;
449 		u32 nr_nsids = le32_to_cpu(desc->nnsids);
450 		size_t nsid_buf_size = nr_nsids * sizeof(__le32);
451 
452 		if (WARN_ON_ONCE(desc->grpid == 0))
453 			return -EINVAL;
454 		if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
455 			return -EINVAL;
456 		if (WARN_ON_ONCE(desc->state == 0))
457 			return -EINVAL;
458 		if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
459 			return -EINVAL;
460 
461 		offset += sizeof(*desc);
462 		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
463 			return -EINVAL;
464 
465 		error = cb(ctrl, desc, data);
466 		if (error)
467 			return error;
468 
469 		offset += nsid_buf_size;
470 		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
471 			return -EINVAL;
472 	}
473 
474 	return 0;
475 }
476 
477 static inline bool nvme_state_is_live(enum nvme_ana_state state)
478 {
479 	return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
480 }
481 
482 static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
483 		struct nvme_ns *ns)
484 {
485 	mutex_lock(&ns->head->lock);
486 	ns->ana_grpid = le32_to_cpu(desc->grpid);
487 	ns->ana_state = desc->state;
488 	clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
489 
490 	if (nvme_state_is_live(ns->ana_state))
491 		nvme_mpath_set_live(ns);
492 	mutex_unlock(&ns->head->lock);
493 }
494 
495 static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
496 		struct nvme_ana_group_desc *desc, void *data)
497 {
498 	u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
499 	unsigned *nr_change_groups = data;
500 	struct nvme_ns *ns;
501 
502 	dev_dbg(ctrl->device, "ANA group %d: %s.\n",
503 			le32_to_cpu(desc->grpid),
504 			nvme_ana_state_names[desc->state]);
505 
506 	if (desc->state == NVME_ANA_CHANGE)
507 		(*nr_change_groups)++;
508 
509 	if (!nr_nsids)
510 		return 0;
511 
512 	down_write(&ctrl->namespaces_rwsem);
513 	list_for_each_entry(ns, &ctrl->namespaces, list) {
514 		unsigned nsid = le32_to_cpu(desc->nsids[n]);
515 
516 		if (ns->head->ns_id < nsid)
517 			continue;
518 		if (ns->head->ns_id == nsid)
519 			nvme_update_ns_ana_state(desc, ns);
520 		if (++n == nr_nsids)
521 			break;
522 	}
523 	up_write(&ctrl->namespaces_rwsem);
524 	return 0;
525 }
526 
527 static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
528 {
529 	u32 nr_change_groups = 0;
530 	int error;
531 
532 	mutex_lock(&ctrl->ana_lock);
533 	error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0,
534 			ctrl->ana_log_buf, ctrl->ana_log_size, 0);
535 	if (error) {
536 		dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
537 		goto out_unlock;
538 	}
539 
540 	error = nvme_parse_ana_log(ctrl, &nr_change_groups,
541 			nvme_update_ana_state);
542 	if (error)
543 		goto out_unlock;
544 
545 	/*
546 	 * In theory we should have an ANATT timer per group as they might enter
547 	 * the change state at different times.  But that is a lot of overhead
548 	 * just to protect against a target that keeps entering new changes
549 	 * states while never finishing previous ones.  But we'll still
550 	 * eventually time out once all groups are in change state, so this
551 	 * isn't a big deal.
552 	 *
553 	 * We also double the ANATT value to provide some slack for transports
554 	 * or AEN processing overhead.
555 	 */
556 	if (nr_change_groups)
557 		mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
558 	else
559 		del_timer_sync(&ctrl->anatt_timer);
560 out_unlock:
561 	mutex_unlock(&ctrl->ana_lock);
562 	return error;
563 }
564 
565 static void nvme_ana_work(struct work_struct *work)
566 {
567 	struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
568 
569 	nvme_read_ana_log(ctrl);
570 }
571 
572 static void nvme_anatt_timeout(struct timer_list *t)
573 {
574 	struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
575 
576 	dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
577 	nvme_reset_ctrl(ctrl);
578 }
579 
580 void nvme_mpath_stop(struct nvme_ctrl *ctrl)
581 {
582 	if (!nvme_ctrl_use_ana(ctrl))
583 		return;
584 	del_timer_sync(&ctrl->anatt_timer);
585 	cancel_work_sync(&ctrl->ana_work);
586 }
587 
588 #define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
589 	struct device_attribute subsys_attr_##_name =	\
590 		__ATTR(_name, _mode, _show, _store)
591 
592 static const char *nvme_iopolicy_names[] = {
593 	[NVME_IOPOLICY_NUMA]	= "numa",
594 	[NVME_IOPOLICY_RR]	= "round-robin",
595 };
596 
597 static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
598 		struct device_attribute *attr, char *buf)
599 {
600 	struct nvme_subsystem *subsys =
601 		container_of(dev, struct nvme_subsystem, dev);
602 
603 	return sprintf(buf, "%s\n",
604 			nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
605 }
606 
607 static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
608 		struct device_attribute *attr, const char *buf, size_t count)
609 {
610 	struct nvme_subsystem *subsys =
611 		container_of(dev, struct nvme_subsystem, dev);
612 	int i;
613 
614 	for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
615 		if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
616 			WRITE_ONCE(subsys->iopolicy, i);
617 			return count;
618 		}
619 	}
620 
621 	return -EINVAL;
622 }
623 SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
624 		      nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);
625 
626 static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
627 		char *buf)
628 {
629 	return sprintf(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
630 }
631 DEVICE_ATTR_RO(ana_grpid);
632 
633 static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
634 		char *buf)
635 {
636 	struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
637 
638 	return sprintf(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
639 }
640 DEVICE_ATTR_RO(ana_state);
641 
642 static int nvme_set_ns_ana_state(struct nvme_ctrl *ctrl,
643 		struct nvme_ana_group_desc *desc, void *data)
644 {
645 	struct nvme_ns *ns = data;
646 
647 	if (ns->ana_grpid == le32_to_cpu(desc->grpid)) {
648 		nvme_update_ns_ana_state(desc, ns);
649 		return -ENXIO; /* just break out of the loop */
650 	}
651 
652 	return 0;
653 }
654 
655 void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
656 {
657 	if (nvme_ctrl_use_ana(ns->ctrl)) {
658 		mutex_lock(&ns->ctrl->ana_lock);
659 		ns->ana_grpid = le32_to_cpu(id->anagrpid);
660 		nvme_parse_ana_log(ns->ctrl, ns, nvme_set_ns_ana_state);
661 		mutex_unlock(&ns->ctrl->ana_lock);
662 	} else {
663 		mutex_lock(&ns->head->lock);
664 		ns->ana_state = NVME_ANA_OPTIMIZED;
665 		nvme_mpath_set_live(ns);
666 		mutex_unlock(&ns->head->lock);
667 	}
668 }
669 
670 void nvme_mpath_remove_disk(struct nvme_ns_head *head)
671 {
672 	if (!head->disk)
673 		return;
674 	if (head->disk->flags & GENHD_FL_UP)
675 		del_gendisk(head->disk);
676 	blk_set_queue_dying(head->disk->queue);
677 	/* make sure all pending bios are cleaned up */
678 	kblockd_schedule_work(&head->requeue_work);
679 	flush_work(&head->requeue_work);
680 	blk_cleanup_queue(head->disk->queue);
681 	put_disk(head->disk);
682 }
683 
684 int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
685 {
686 	int error;
687 
688 	/* check if multipath is enabled and we have the capability */
689 	if (!multipath || !ctrl->subsys || !(ctrl->subsys->cmic & (1 << 3)))
690 		return 0;
691 
692 	ctrl->anacap = id->anacap;
693 	ctrl->anatt = id->anatt;
694 	ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
695 	ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
696 
697 	mutex_init(&ctrl->ana_lock);
698 	timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
699 	ctrl->ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
700 		ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc);
701 	ctrl->ana_log_size += ctrl->max_namespaces * sizeof(__le32);
702 
703 	if (ctrl->ana_log_size > ctrl->max_hw_sectors << SECTOR_SHIFT) {
704 		dev_err(ctrl->device,
705 			"ANA log page size (%zd) larger than MDTS (%d).\n",
706 			ctrl->ana_log_size,
707 			ctrl->max_hw_sectors << SECTOR_SHIFT);
708 		dev_err(ctrl->device, "disabling ANA support.\n");
709 		return 0;
710 	}
711 
712 	INIT_WORK(&ctrl->ana_work, nvme_ana_work);
713 	ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
714 	if (!ctrl->ana_log_buf) {
715 		error = -ENOMEM;
716 		goto out;
717 	}
718 
719 	error = nvme_read_ana_log(ctrl);
720 	if (error)
721 		goto out_free_ana_log_buf;
722 	return 0;
723 out_free_ana_log_buf:
724 	kfree(ctrl->ana_log_buf);
725 	ctrl->ana_log_buf = NULL;
726 out:
727 	return error;
728 }
729 
730 void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
731 {
732 	kfree(ctrl->ana_log_buf);
733 	ctrl->ana_log_buf = NULL;
734 }
735 
736