drivers/nvme/host/multipath.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2017-2018 Christoph Hellwig.
   4  */
   5
   6 #include <linux/backing-dev.h>
   7 #include <linux/moduleparam.h>
   8 #include <trace/events/block.h>
   9 #include "nvme.h"
  10
  11 static bool multipath = true;
  12 module_param(multipath, bool, 0444);
  13 MODULE_PARM_DESC(multipath,
  14         "turn on native support for multiple controllers per subsystem");
  15
  16 void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
  17 {
  18         struct nvme_ns_head *h;
  19
  20         lockdep_assert_held(&subsys->lock);
  21         list_for_each_entry(h, &subsys->nsheads, entry)
  22                 if (h->disk)
  23                         blk_mq_unfreeze_queue(h->disk->queue);
  24 }
  25
  26 void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
  27 {
  28         struct nvme_ns_head *h;
  29
  30         lockdep_assert_held(&subsys->lock);
  31         list_for_each_entry(h, &subsys->nsheads, entry)
  32                 if (h->disk)
  33                         blk_mq_freeze_queue_wait(h->disk->queue);
  34 }
  35
  36 void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
  37 {
  38         struct nvme_ns_head *h;
  39
  40         lockdep_assert_held(&subsys->lock);
  41         list_for_each_entry(h, &subsys->nsheads, entry)
  42                 if (h->disk)
  43                         blk_freeze_queue_start(h->disk->queue);
  44 }
  45
  46 /*
  47  * If multipathing is enabled we need to always use the subsystem instance
  48  * number for numbering our devices to avoid conflicts between subsystems that
  49  * have multiple controllers and thus use the multipath-aware subsystem node
  50  * and those that have a single controller and use the controller node
  51  * directly.
  52  */
  53 bool nvme_mpath_set_disk_name(struct nvme_ns *ns, char *disk_name, int *flags)
  54 {
  55         if (!multipath)
  56                 return false;
  57         if (!ns->head->disk) {
  58                 sprintf(disk_name, "nvme%dn%d", ns->ctrl->subsys->instance,
  59                         ns->head->instance);
  60                 return true;
  61         }
  62         sprintf(disk_name, "nvme%dc%dn%d", ns->ctrl->subsys->instance,
  63                 ns->ctrl->instance, ns->head->instance);
  64         *flags = GENHD_FL_HIDDEN;
  65         return true;
  66 }
  67
  68 void nvme_failover_req(struct request *req)
  69 {
  70         struct nvme_ns *ns = req->q->queuedata;
  71         u16 status = nvme_req(req)->status & 0x7ff;
  72         unsigned long flags;
  73         struct bio *bio;
  74
  75         nvme_mpath_clear_current_path(ns);
  76
  77         /*
  78          * If we got back an ANA error, we know the controller is alive but not
  79          * ready to serve this namespace.  Kick of a re-read of the ANA
  80          * information page, and just try any other available path for now.
  81          */
  82         if (nvme_is_ana_error(status) && ns->ctrl->ana_log_buf) {
  83                 set_bit(NVME_NS_ANA_PENDING, &ns->flags);
  84                 queue_work(nvme_wq, &ns->ctrl->ana_work);
  85         }
  86
  87         spin_lock_irqsave(&ns->head->requeue_lock, flags);
  88         for (bio = req->bio; bio; bio = bio->bi_next)
  89                 bio_set_dev(bio, ns->head->disk->part0);
  90         blk_steal_bios(&ns->head->requeue_list, req);
  91         spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
  92
  93         blk_mq_end_request(req, 0);
  94         kblockd_schedule_work(&ns->head->requeue_work);
  95 }
  96
  97 void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
  98 {
  99         struct nvme_ns *ns;
 100
 101         down_read(&ctrl->namespaces_rwsem);
 102         list_for_each_entry(ns, &ctrl->namespaces, list) {
 103                 if (ns->head->disk)
 104                         kblockd_schedule_work(&ns->head->requeue_work);
 105         }
 106         up_read(&ctrl->namespaces_rwsem);
 107 }
 108
 109 static const char *nvme_ana_state_names[] = {
 110         [0]                             = "invalid state",
 111         [NVME_ANA_OPTIMIZED]            = "optimized",
 112         [NVME_ANA_NONOPTIMIZED]         = "non-optimized",
 113         [NVME_ANA_INACCESSIBLE]         = "inaccessible",
 114         [NVME_ANA_PERSISTENT_LOSS]      = "persistent-loss",
 115         [NVME_ANA_CHANGE]               = "change",
 116 };
 117
 118 bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
 119 {
 120         struct nvme_ns_head *head = ns->head;
 121         bool changed = false;
 122         int node;
 123
 124         if (!head)
 125                 goto out;
 126
 127         for_each_node(node) {
 128                 if (ns == rcu_access_pointer(head->current_path[node])) {
 129                         rcu_assign_pointer(head->current_path[node], NULL);
 130                         changed = true;
 131                 }
 132         }
 133 out:
 134         return changed;
 135 }
 136
 137 void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
 138 {
 139         struct nvme_ns *ns;
 140
 141         mutex_lock(&ctrl->scan_lock);
 142         down_read(&ctrl->namespaces_rwsem);
 143         list_for_each_entry(ns, &ctrl->namespaces, list)
 144                 if (nvme_mpath_clear_current_path(ns))
 145                         kblockd_schedule_work(&ns->head->requeue_work);
 146         up_read(&ctrl->namespaces_rwsem);
 147         mutex_unlock(&ctrl->scan_lock);
 148 }
 149
 150 static bool nvme_path_is_disabled(struct nvme_ns *ns)
 151 {
 152         /*
 153          * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should
 154          * still be able to complete assuming that the controller is connected.
 155          * Otherwise it will fail immediately and return to the requeue list.
 156          */
 157         if (ns->ctrl->state != NVME_CTRL_LIVE &&
 158             ns->ctrl->state != NVME_CTRL_DELETING)
 159                 return true;
 160         if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
 161             test_bit(NVME_NS_REMOVING, &ns->flags))
 162                 return true;
 163         return false;
 164 }
 165
 166 static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
 167 {
 168         int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
 169         struct nvme_ns *found = NULL, *fallback = NULL, *ns;
 170
 171         list_for_each_entry_rcu(ns, &head->list, siblings) {
 172                 if (nvme_path_is_disabled(ns))
 173                         continue;
 174
 175                 if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
 176                         distance = node_distance(node, ns->ctrl->numa_node);
 177                 else
 178                         distance = LOCAL_DISTANCE;
 179
 180                 switch (ns->ana_state) {
 181                 case NVME_ANA_OPTIMIZED:
 182                         if (distance < found_distance) {
 183                                 found_distance = distance;
 184                                 found = ns;
 185                         }
 186                         break;
 187                 case NVME_ANA_NONOPTIMIZED:
 188                         if (distance < fallback_distance) {
 189                                 fallback_distance = distance;
 190                                 fallback = ns;
 191                         }
 192                         break;
 193                 default:
 194                         break;
 195                 }
 196         }
 197
 198         if (!found)
 199                 found = fallback;
 200         if (found)
 201                 rcu_assign_pointer(head->current_path[node], found);
 202         return found;
 203 }
 204
 205 static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
 206                 struct nvme_ns *ns)
 207 {
 208         ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
 209                         siblings);
 210         if (ns)
 211                 return ns;
 212         return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
 213 }
 214
 215 static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 216                 int node, struct nvme_ns *old)
 217 {
 218         struct nvme_ns *ns, *found = NULL;
 219
 220         if (list_is_singular(&head->list)) {
 221                 if (nvme_path_is_disabled(old))
 222                         return NULL;
 223                 return old;
 224         }
 225
 226         for (ns = nvme_next_ns(head, old);
 227              ns && ns != old;
 228              ns = nvme_next_ns(head, ns)) {
 229                 if (nvme_path_is_disabled(ns))
 230                         continue;
 231
 232                 if (ns->ana_state == NVME_ANA_OPTIMIZED) {
 233                         found = ns;
 234                         goto out;
 235                 }
 236                 if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
 237                         found = ns;
 238         }
 239
 240         /*
 241          * The loop above skips the current path for round-robin semantics.
 242          * Fall back to the current path if either:
 243          *  - no other optimized path found and current is optimized,
 244          *  - no other usable path found and current is usable.
 245          */
 246         if (!nvme_path_is_disabled(old) &&
 247             (old->ana_state == NVME_ANA_OPTIMIZED ||
 248              (!found && old->ana_state == NVME_ANA_NONOPTIMIZED)))
 249                 return old;
 250
 251         if (!found)
 252                 return NULL;
 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 (unlikely(!ns))
 271                 return __nvme_find_path(head, node);
 272
 273         if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
 274                 return nvme_round_robin_path(head, node, ns);
 275         if (unlikely(!nvme_path_is_optimized(ns)))
 276                 return __nvme_find_path(head, node);
 277         return ns;
 278 }
 279
 280 static bool nvme_available_path(struct nvme_ns_head *head)
 281 {
 282         struct nvme_ns *ns;
 283
 284         list_for_each_entry_rcu(ns, &head->list, siblings) {
 285                 if (test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ns->ctrl->flags))
 286                         continue;
 287                 switch (ns->ctrl->state) {
 288                 case NVME_CTRL_LIVE:
 289                 case NVME_CTRL_RESETTING:
 290                 case NVME_CTRL_CONNECTING:
 291                         /* fallthru */
 292                         return true;
 293                 default:
 294                         break;
 295                 }
 296         }
 297         return false;
 298 }
 299
 300 static blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
 301 {
 302         struct nvme_ns_head *head = bio->bi_bdev->bd_disk->private_data;
 303         struct device *dev = disk_to_dev(head->disk);
 304         struct nvme_ns *ns;
 305         blk_qc_t ret = BLK_QC_T_NONE;
 306         int srcu_idx;
 307
 308         /*
 309          * The namespace might be going away and the bio might be moved to a
 310          * different queue via blk_steal_bios(), so we need to use the bio_split
 311          * pool from the original queue to allocate the bvecs from.
 312          */
 313         blk_queue_split(&bio);
 314
 315         srcu_idx = srcu_read_lock(&head->srcu);
 316         ns = nvme_find_path(head);
 317         if (likely(ns)) {
 318                 bio_set_dev(bio, ns->disk->part0);
 319                 bio->bi_opf |= REQ_NVME_MPATH;
 320                 trace_block_bio_remap(bio, disk_devt(ns->head->disk),
 321                                       bio->bi_iter.bi_sector);
 322                 ret = submit_bio_noacct(bio);
 323         } else if (nvme_available_path(head)) {
 324                 dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
 325
 326                 spin_lock_irq(&head->requeue_lock);
 327                 bio_list_add(&head->requeue_list, bio);
 328                 spin_unlock_irq(&head->requeue_lock);
 329         } else {
 330                 dev_warn_ratelimited(dev, "no available path - failing I/O\n");
 331
 332                 bio->bi_status = BLK_STS_IOERR;
 333                 bio_endio(bio);
 334         }
 335
 336         srcu_read_unlock(&head->srcu, srcu_idx);
 337         return ret;
 338 }
 339
 340 static int nvme_ns_head_open(struct block_device *bdev, fmode_t mode)
 341 {
 342         if (!nvme_tryget_ns_head(bdev->bd_disk->private_data))
 343                 return -ENXIO;
 344         return 0;
 345 }
 346
 347 static void nvme_ns_head_release(struct gendisk *disk, fmode_t mode)
 348 {
 349         nvme_put_ns_head(disk->private_data);
 350 }
 351
 352 #ifdef CONFIG_BLK_DEV_ZONED
 353 static int nvme_ns_head_report_zones(struct gendisk *disk, sector_t sector,
 354                 unsigned int nr_zones, report_zones_cb cb, void *data)
 355 {
 356         struct nvme_ns_head *head = disk->private_data;
 357         struct nvme_ns *ns;
 358         int srcu_idx, ret = -EWOULDBLOCK;
 359
 360         srcu_idx = srcu_read_lock(&head->srcu);
 361         ns = nvme_find_path(head);
 362         if (ns)
 363                 ret = nvme_ns_report_zones(ns, sector, nr_zones, cb, data);
 364         srcu_read_unlock(&head->srcu, srcu_idx);
 365         return ret;
 366 }
 367 #else
 368 #define nvme_ns_head_report_zones       NULL
 369 #endif /* CONFIG_BLK_DEV_ZONED */
 370
 371 const struct block_device_operations nvme_ns_head_ops = {
 372         .owner          = THIS_MODULE,
 373         .submit_bio     = nvme_ns_head_submit_bio,
 374         .open           = nvme_ns_head_open,
 375         .release        = nvme_ns_head_release,
 376         .ioctl          = nvme_ns_head_ioctl,
 377         .getgeo         = nvme_getgeo,
 378         .report_zones   = nvme_ns_head_report_zones,
 379         .pr_ops         = &nvme_pr_ops,
 380 };
 381
 382 static inline struct nvme_ns_head *cdev_to_ns_head(struct cdev *cdev)
 383 {
 384         return container_of(cdev, struct nvme_ns_head, cdev);
 385 }
 386
 387 static int nvme_ns_head_chr_open(struct inode *inode, struct file *file)
 388 {
 389         if (!nvme_tryget_ns_head(cdev_to_ns_head(inode->i_cdev)))
 390                 return -ENXIO;
 391         return 0;
 392 }
 393
 394 static int nvme_ns_head_chr_release(struct inode *inode, struct file *file)
 395 {
 396         nvme_put_ns_head(cdev_to_ns_head(inode->i_cdev));
 397         return 0;
 398 }
 399
 400 static const struct file_operations nvme_ns_head_chr_fops = {
 401         .owner          = THIS_MODULE,
 402         .open           = nvme_ns_head_chr_open,
 403         .release        = nvme_ns_head_chr_release,
 404         .unlocked_ioctl = nvme_ns_head_chr_ioctl,
 405         .compat_ioctl   = compat_ptr_ioctl,
 406 };
 407
 408 static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
 409 {
 410         int ret;
 411
 412         head->cdev_device.parent = &head->subsys->dev;
 413         ret = dev_set_name(&head->cdev_device, "ng%dn%d",
 414                            head->subsys->instance, head->instance);
 415         if (ret)
 416                 return ret;
 417         ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
 418                             &nvme_ns_head_chr_fops, THIS_MODULE);
 419         if (ret)
 420                 kfree_const(head->cdev_device.kobj.name);
 421         return ret;
 422 }
 423
 424 static void nvme_requeue_work(struct work_struct *work)
 425 {
 426         struct nvme_ns_head *head =
 427                 container_of(work, struct nvme_ns_head, requeue_work);
 428         struct bio *bio, *next;
 429
 430         spin_lock_irq(&head->requeue_lock);
 431         next = bio_list_get(&head->requeue_list);
 432         spin_unlock_irq(&head->requeue_lock);
 433
 434         while ((bio = next) != NULL) {
 435                 next = bio->bi_next;
 436                 bio->bi_next = NULL;
 437
 438                 submit_bio_noacct(bio);
 439         }
 440 }
 441
 442 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 443 {
 444         struct request_queue *q;
 445         bool vwc = false;
 446
 447         mutex_init(&head->lock);
 448         bio_list_init(&head->requeue_list);
 449         spin_lock_init(&head->requeue_lock);
 450         INIT_WORK(&head->requeue_work, nvme_requeue_work);
 451
 452         /*
 453          * Add a multipath node if the subsystems supports multiple controllers.
 454          * We also do this for private namespaces as the namespace sharing data could
 455          * change after a rescan.
 456          */
 457         if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) || !multipath)
 458                 return 0;
 459
 460         q = blk_alloc_queue(ctrl->numa_node);
 461         if (!q)
 462                 goto out;
 463         blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 464         /* set to a default value for 512 until disk is validated */
 465         blk_queue_logical_block_size(q, 512);
 466         blk_set_stacking_limits(&q->limits);
 467
 468         /* we need to propagate up the VMC settings */
 469         if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
 470                 vwc = true;
 471         blk_queue_write_cache(q, vwc, vwc);
 472
 473         head->disk = alloc_disk(0);
 474         if (!head->disk)
 475                 goto out_cleanup_queue;
 476         head->disk->fops = &nvme_ns_head_ops;
 477         head->disk->private_data = head;
 478         head->disk->queue = q;
 479         head->disk->flags = GENHD_FL_EXT_DEVT;
 480         sprintf(head->disk->disk_name, "nvme%dn%d",
 481                         ctrl->subsys->instance, head->instance);
 482         return 0;
 483
 484 out_cleanup_queue:
 485         blk_cleanup_queue(q);
 486 out:
 487         return -ENOMEM;
 488 }
 489
 490 static void nvme_mpath_set_live(struct nvme_ns *ns)
 491 {
 492         struct nvme_ns_head *head = ns->head;
 493
 494         if (!head->disk)
 495                 return;
 496
 497         if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
 498                 device_add_disk(&head->subsys->dev, head->disk,
 499                                 nvme_ns_id_attr_groups);
 500                 nvme_add_ns_head_cdev(head);
 501         }
 502
 503         mutex_lock(&head->lock);
 504         if (nvme_path_is_optimized(ns)) {
 505                 int node, srcu_idx;
 506
 507                 srcu_idx = srcu_read_lock(&head->srcu);
 508                 for_each_node(node)
 509                         __nvme_find_path(head, node);
 510                 srcu_read_unlock(&head->srcu, srcu_idx);
 511         }
 512         mutex_unlock(&head->lock);
 513
 514         synchronize_srcu(&head->srcu);
 515         kblockd_schedule_work(&head->requeue_work);
 516 }
 517
 518 static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
 519                 int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
 520                         void *))
 521 {
 522         void *base = ctrl->ana_log_buf;
 523         size_t offset = sizeof(struct nvme_ana_rsp_hdr);
 524         int error, i;
 525
 526         lockdep_assert_held(&ctrl->ana_lock);
 527
 528         for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
 529                 struct nvme_ana_group_desc *desc = base + offset;
 530                 u32 nr_nsids;
 531                 size_t nsid_buf_size;
 532
 533                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
 534                         return -EINVAL;
 535
 536                 nr_nsids = le32_to_cpu(desc->nnsids);
 537                 nsid_buf_size = nr_nsids * sizeof(__le32);
 538
 539                 if (WARN_ON_ONCE(desc->grpid == 0))
 540                         return -EINVAL;
 541                 if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
 542                         return -EINVAL;
 543                 if (WARN_ON_ONCE(desc->state == 0))
 544                         return -EINVAL;
 545                 if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
 546                         return -EINVAL;
 547
 548                 offset += sizeof(*desc);
 549                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
 550                         return -EINVAL;
 551
 552                 error = cb(ctrl, desc, data);
 553                 if (error)
 554                         return error;
 555
 556                 offset += nsid_buf_size;
 557         }
 558
 559         return 0;
 560 }
 561
 562 static inline bool nvme_state_is_live(enum nvme_ana_state state)
 563 {
 564         return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
 565 }
 566
 567 static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
 568                 struct nvme_ns *ns)
 569 {
 570         ns->ana_grpid = le32_to_cpu(desc->grpid);
 571         ns->ana_state = desc->state;
 572         clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
 573
 574         if (nvme_state_is_live(ns->ana_state))
 575                 nvme_mpath_set_live(ns);
 576 }
 577
 578 static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
 579                 struct nvme_ana_group_desc *desc, void *data)
 580 {
 581         u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
 582         unsigned *nr_change_groups = data;
 583         struct nvme_ns *ns;
 584
 585         dev_dbg(ctrl->device, "ANA group %d: %s.\n",
 586                         le32_to_cpu(desc->grpid),
 587                         nvme_ana_state_names[desc->state]);
 588
 589         if (desc->state == NVME_ANA_CHANGE)
 590                 (*nr_change_groups)++;
 591
 592         if (!nr_nsids)
 593                 return 0;
 594
 595         down_read(&ctrl->namespaces_rwsem);
 596         list_for_each_entry(ns, &ctrl->namespaces, list) {
 597                 unsigned nsid = le32_to_cpu(desc->nsids[n]);
 598
 599                 if (ns->head->ns_id < nsid)
 600                         continue;
 601                 if (ns->head->ns_id == nsid)
 602                         nvme_update_ns_ana_state(desc, ns);
 603                 if (++n == nr_nsids)
 604                         break;
 605         }
 606         up_read(&ctrl->namespaces_rwsem);
 607         return 0;
 608 }
 609
 610 static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
 611 {
 612         u32 nr_change_groups = 0;
 613         int error;
 614
 615         mutex_lock(&ctrl->ana_lock);
 616         error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0, NVME_CSI_NVM,
 617                         ctrl->ana_log_buf, ctrl->ana_log_size, 0);
 618         if (error) {
 619                 dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
 620                 goto out_unlock;
 621         }
 622
 623         error = nvme_parse_ana_log(ctrl, &nr_change_groups,
 624                         nvme_update_ana_state);
 625         if (error)
 626                 goto out_unlock;
 627
 628         /*
 629          * In theory we should have an ANATT timer per group as they might enter
 630          * the change state at different times.  But that is a lot of overhead
 631          * just to protect against a target that keeps entering new changes
 632          * states while never finishing previous ones.  But we'll still
 633          * eventually time out once all groups are in change state, so this
 634          * isn't a big deal.
 635          *
 636          * We also double the ANATT value to provide some slack for transports
 637          * or AEN processing overhead.
 638          */
 639         if (nr_change_groups)
 640                 mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
 641         else
 642                 del_timer_sync(&ctrl->anatt_timer);
 643 out_unlock:
 644         mutex_unlock(&ctrl->ana_lock);
 645         return error;
 646 }
 647
 648 static void nvme_ana_work(struct work_struct *work)
 649 {
 650         struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
 651
 652         if (ctrl->state != NVME_CTRL_LIVE)
 653                 return;
 654
 655         nvme_read_ana_log(ctrl);
 656 }
 657
 658 static void nvme_anatt_timeout(struct timer_list *t)
 659 {
 660         struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
 661
 662         dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
 663         nvme_reset_ctrl(ctrl);
 664 }
 665
 666 void nvme_mpath_stop(struct nvme_ctrl *ctrl)
 667 {
 668         if (!nvme_ctrl_use_ana(ctrl))
 669                 return;
 670         del_timer_sync(&ctrl->anatt_timer);
 671         cancel_work_sync(&ctrl->ana_work);
 672 }
 673
 674 #define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
 675         struct device_attribute subsys_attr_##_name =   \
 676                 __ATTR(_name, _mode, _show, _store)
 677
 678 static const char *nvme_iopolicy_names[] = {
 679         [NVME_IOPOLICY_NUMA]    = "numa",
 680         [NVME_IOPOLICY_RR]      = "round-robin",
 681 };
 682
 683 static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
 684                 struct device_attribute *attr, char *buf)
 685 {
 686         struct nvme_subsystem *subsys =
 687                 container_of(dev, struct nvme_subsystem, dev);
 688
 689         return sysfs_emit(buf, "%s\n",
 690                           nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
 691 }
 692
 693 static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
 694                 struct device_attribute *attr, const char *buf, size_t count)
 695 {
 696         struct nvme_subsystem *subsys =
 697                 container_of(dev, struct nvme_subsystem, dev);
 698         int i;
 699
 700         for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
 701                 if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
 702                         WRITE_ONCE(subsys->iopolicy, i);
 703                         return count;
 704                 }
 705         }
 706
 707         return -EINVAL;
 708 }
 709 SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
 710                       nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);
 711
 712 static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
 713                 char *buf)
 714 {
 715         return sysfs_emit(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
 716 }
 717 DEVICE_ATTR_RO(ana_grpid);
 718
 719 static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
 720                 char *buf)
 721 {
 722         struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
 723
 724         return sysfs_emit(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
 725 }
 726 DEVICE_ATTR_RO(ana_state);
 727
 728 static int nvme_lookup_ana_group_desc(struct nvme_ctrl *ctrl,
 729                 struct nvme_ana_group_desc *desc, void *data)
 730 {
 731         struct nvme_ana_group_desc *dst = data;
 732
 733         if (desc->grpid != dst->grpid)
 734                 return 0;
 735
 736         *dst = *desc;
 737         return -ENXIO; /* just break out of the loop */
 738 }
 739
 740 void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
 741 {
 742         if (nvme_ctrl_use_ana(ns->ctrl)) {
 743                 struct nvme_ana_group_desc desc = {
 744                         .grpid = id->anagrpid,
 745                         .state = 0,
 746                 };
 747
 748                 mutex_lock(&ns->ctrl->ana_lock);
 749                 ns->ana_grpid = le32_to_cpu(id->anagrpid);
 750                 nvme_parse_ana_log(ns->ctrl, &desc, nvme_lookup_ana_group_desc);
 751                 mutex_unlock(&ns->ctrl->ana_lock);
 752                 if (desc.state) {
 753                         /* found the group desc: update */
 754                         nvme_update_ns_ana_state(&desc, ns);
 755                 } else {
 756                         /* group desc not found: trigger a re-read */
 757                         set_bit(NVME_NS_ANA_PENDING, &ns->flags);
 758                         queue_work(nvme_wq, &ns->ctrl->ana_work);
 759                 }
 760         } else {
 761                 ns->ana_state = NVME_ANA_OPTIMIZED;
 762                 nvme_mpath_set_live(ns);
 763         }
 764
 765         if (blk_queue_stable_writes(ns->queue) && ns->head->disk)
 766                 blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
 767                                    ns->head->disk->queue);
 768 #ifdef CONFIG_BLK_DEV_ZONED
 769         if (blk_queue_is_zoned(ns->queue) && ns->head->disk)
 770                 ns->head->disk->queue->nr_zones = ns->queue->nr_zones;
 771 #endif
 772 }
 773
 774 void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 775 {
 776         if (!head->disk)
 777                 return;
 778         if (head->disk->flags & GENHD_FL_UP) {
 779                 nvme_cdev_del(&head->cdev, &head->cdev_device);
 780                 del_gendisk(head->disk);
 781         }
 782         blk_set_queue_dying(head->disk->queue);
 783         /* make sure all pending bios are cleaned up */
 784         kblockd_schedule_work(&head->requeue_work);
 785         flush_work(&head->requeue_work);
 786         blk_cleanup_queue(head->disk->queue);
 787         if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
 788                 /*
 789                  * if device_add_disk wasn't called, prevent
 790                  * disk release to put a bogus reference on the
 791                  * request queue
 792                  */
 793                 head->disk->queue = NULL;
 794         }
 795         put_disk(head->disk);
 796 }
 797
 798 void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl)
 799 {
 800         mutex_init(&ctrl->ana_lock);
 801         timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
 802         INIT_WORK(&ctrl->ana_work, nvme_ana_work);
 803 }
 804
 805 int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 806 {
 807         size_t max_transfer_size = ctrl->max_hw_sectors << SECTOR_SHIFT;
 808         size_t ana_log_size;
 809         int error = 0;
 810
 811         /* check if multipath is enabled and we have the capability */
 812         if (!multipath || !ctrl->subsys ||
 813             !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
 814                 return 0;
 815
 816         if (!ctrl->max_namespaces ||
 817             ctrl->max_namespaces > le32_to_cpu(id->nn)) {
 818                 dev_err(ctrl->device,
 819                         "Invalid MNAN value %u\n", ctrl->max_namespaces);
 820                 return -EINVAL;
 821         }
 822
 823         ctrl->anacap = id->anacap;
 824         ctrl->anatt = id->anatt;
 825         ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
 826         ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
 827
 828         ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
 829                 ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc) +
 830                 ctrl->max_namespaces * sizeof(__le32);
 831         if (ana_log_size > max_transfer_size) {
 832                 dev_err(ctrl->device,
 833                         "ANA log page size (%zd) larger than MDTS (%zd).\n",
 834                         ana_log_size, max_transfer_size);
 835                 dev_err(ctrl->device, "disabling ANA support.\n");
 836                 goto out_uninit;
 837         }
 838         if (ana_log_size > ctrl->ana_log_size) {
 839                 nvme_mpath_stop(ctrl);
 840                 kfree(ctrl->ana_log_buf);
 841                 ctrl->ana_log_buf = kmalloc(ana_log_size, GFP_KERNEL);
 842                 if (!ctrl->ana_log_buf)
 843                         return -ENOMEM;
 844         }
 845         ctrl->ana_log_size = ana_log_size;
 846         error = nvme_read_ana_log(ctrl);
 847         if (error)
 848                 goto out_uninit;
 849         return 0;
 850
 851 out_uninit:
 852         nvme_mpath_uninit(ctrl);
 853         return error;
 854 }
 855
 856 void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
 857 {
 858         kfree(ctrl->ana_log_buf);
 859         ctrl->ana_log_buf = NULL;
 860 }