drivers/nvme/host/multipath.c

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