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 <linux/vmalloc.h>
   9 #include <trace/events/block.h>
  10 #include "nvme.h"
  11
  12 bool multipath = true;
  13 module_param(multipath, bool, 0444);
  14 MODULE_PARM_DESC(multipath,
  15         "turn on native support for multiple controllers per subsystem");
  16
  17 static const char *nvme_iopolicy_names[] = {
  18         [NVME_IOPOLICY_NUMA]    = "numa",
  19         [NVME_IOPOLICY_RR]      = "round-robin",
  20 };
  21
  22 static int iopolicy = NVME_IOPOLICY_NUMA;
  23
  24 static int nvme_set_iopolicy(const char *val, const struct kernel_param *kp)
  25 {
  26         if (!val)
  27                 return -EINVAL;
  28         if (!strncmp(val, "numa", 4))
  29                 iopolicy = NVME_IOPOLICY_NUMA;
  30         else if (!strncmp(val, "round-robin", 11))
  31                 iopolicy = NVME_IOPOLICY_RR;
  32         else
  33                 return -EINVAL;
  34
  35         return 0;
  36 }
  37
  38 static int nvme_get_iopolicy(char *buf, const struct kernel_param *kp)
  39 {
  40         return sprintf(buf, "%s\n", nvme_iopolicy_names[iopolicy]);
  41 }
  42
  43 module_param_call(iopolicy, nvme_set_iopolicy, nvme_get_iopolicy,
  44         &iopolicy, 0644);
  45 MODULE_PARM_DESC(iopolicy,
  46         "Default multipath I/O policy; 'numa' (default) or 'round-robin'");
  47
  48 void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys)
  49 {
  50         subsys->iopolicy = iopolicy;
  51 }
  52
  53 void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
  54 {
  55         struct nvme_ns_head *h;
  56
  57         lockdep_assert_held(&subsys->lock);
  58         list_for_each_entry(h, &subsys->nsheads, entry)
  59                 if (h->disk)
  60                         blk_mq_unfreeze_queue(h->disk->queue);
  61 }
  62
  63 void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
  64 {
  65         struct nvme_ns_head *h;
  66
  67         lockdep_assert_held(&subsys->lock);
  68         list_for_each_entry(h, &subsys->nsheads, entry)
  69                 if (h->disk)
  70                         blk_mq_freeze_queue_wait(h->disk->queue);
  71 }
  72
  73 void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
  74 {
  75         struct nvme_ns_head *h;
  76
  77         lockdep_assert_held(&subsys->lock);
  78         list_for_each_entry(h, &subsys->nsheads, entry)
  79                 if (h->disk)
  80                         blk_freeze_queue_start(h->disk->queue);
  81 }
  82
  83 void nvme_failover_req(struct request *req)
  84 {
  85         struct nvme_ns *ns = req->q->queuedata;
  86         u16 status = nvme_req(req)->status & 0x7ff;
  87         unsigned long flags;
  88         struct bio *bio;
  89
  90         nvme_mpath_clear_current_path(ns);
  91
  92         /*
  93          * If we got back an ANA error, we know the controller is alive but not
  94          * ready to serve this namespace.  Kick of a re-read of the ANA
  95          * information page, and just try any other available path for now.
  96          */
  97         if (nvme_is_ana_error(status) && ns->ctrl->ana_log_buf) {
  98                 set_bit(NVME_NS_ANA_PENDING, &ns->flags);
  99                 queue_work(nvme_wq, &ns->ctrl->ana_work);
 100         }
 101
 102         spin_lock_irqsave(&ns->head->requeue_lock, flags);
 103         for (bio = req->bio; bio; bio = bio->bi_next) {
 104                 bio_set_dev(bio, ns->head->disk->part0);
 105                 if (bio->bi_opf & REQ_POLLED) {
 106                         bio->bi_opf &= ~REQ_POLLED;
 107                         bio->bi_cookie = BLK_QC_T_NONE;
 108                 }
 109         }
 110         blk_steal_bios(&ns->head->requeue_list, req);
 111         spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
 112
 113         blk_mq_end_request(req, 0);
 114         kblockd_schedule_work(&ns->head->requeue_work);
 115 }
 116
 117 void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
 118 {
 119         struct nvme_ns *ns;
 120
 121         down_read(&ctrl->namespaces_rwsem);
 122         list_for_each_entry(ns, &ctrl->namespaces, list) {
 123                 if (!ns->head->disk)
 124                         continue;
 125                 kblockd_schedule_work(&ns->head->requeue_work);
 126                 if (ctrl->state == NVME_CTRL_LIVE)
 127                         disk_uevent(ns->head->disk, KOBJ_CHANGE);
 128         }
 129         up_read(&ctrl->namespaces_rwsem);
 130 }
 131
 132 static const char *nvme_ana_state_names[] = {
 133         [0]                             = "invalid state",
 134         [NVME_ANA_OPTIMIZED]            = "optimized",
 135         [NVME_ANA_NONOPTIMIZED]         = "non-optimized",
 136         [NVME_ANA_INACCESSIBLE]         = "inaccessible",
 137         [NVME_ANA_PERSISTENT_LOSS]      = "persistent-loss",
 138         [NVME_ANA_CHANGE]               = "change",
 139 };
 140
 141 bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
 142 {
 143         struct nvme_ns_head *head = ns->head;
 144         bool changed = false;
 145         int node;
 146
 147         if (!head)
 148                 goto out;
 149
 150         for_each_node(node) {
 151                 if (ns == rcu_access_pointer(head->current_path[node])) {
 152                         rcu_assign_pointer(head->current_path[node], NULL);
 153                         changed = true;
 154                 }
 155         }
 156 out:
 157         return changed;
 158 }
 159
 160 void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
 161 {
 162         struct nvme_ns *ns;
 163
 164         down_read(&ctrl->namespaces_rwsem);
 165         list_for_each_entry(ns, &ctrl->namespaces, list) {
 166                 nvme_mpath_clear_current_path(ns);
 167                 kblockd_schedule_work(&ns->head->requeue_work);
 168         }
 169         up_read(&ctrl->namespaces_rwsem);
 170 }
 171
 172 void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
 173 {
 174         struct nvme_ns_head *head = ns->head;
 175         sector_t capacity = get_capacity(head->disk);
 176         int node;
 177
 178         list_for_each_entry_rcu(ns, &head->list, siblings) {
 179                 if (capacity != get_capacity(ns->disk))
 180                         clear_bit(NVME_NS_READY, &ns->flags);
 181         }
 182
 183         for_each_node(node)
 184                 rcu_assign_pointer(head->current_path[node], NULL);
 185 }
 186
 187 static bool nvme_path_is_disabled(struct nvme_ns *ns)
 188 {
 189         /*
 190          * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should
 191          * still be able to complete assuming that the controller is connected.
 192          * Otherwise it will fail immediately and return to the requeue list.
 193          */
 194         if (ns->ctrl->state != NVME_CTRL_LIVE &&
 195             ns->ctrl->state != NVME_CTRL_DELETING)
 196                 return true;
 197         if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
 198             !test_bit(NVME_NS_READY, &ns->flags))
 199                 return true;
 200         return false;
 201 }
 202
 203 static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
 204 {
 205         int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
 206         struct nvme_ns *found = NULL, *fallback = NULL, *ns;
 207
 208         list_for_each_entry_rcu(ns, &head->list, siblings) {
 209                 if (nvme_path_is_disabled(ns))
 210                         continue;
 211
 212                 if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
 213                         distance = node_distance(node, ns->ctrl->numa_node);
 214                 else
 215                         distance = LOCAL_DISTANCE;
 216
 217                 switch (ns->ana_state) {
 218                 case NVME_ANA_OPTIMIZED:
 219                         if (distance < found_distance) {
 220                                 found_distance = distance;
 221                                 found = ns;
 222                         }
 223                         break;
 224                 case NVME_ANA_NONOPTIMIZED:
 225                         if (distance < fallback_distance) {
 226                                 fallback_distance = distance;
 227                                 fallback = ns;
 228                         }
 229                         break;
 230                 default:
 231                         break;
 232                 }
 233         }
 234
 235         if (!found)
 236                 found = fallback;
 237         if (found)
 238                 rcu_assign_pointer(head->current_path[node], found);
 239         return found;
 240 }
 241
 242 static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
 243                 struct nvme_ns *ns)
 244 {
 245         ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
 246                         siblings);
 247         if (ns)
 248                 return ns;
 249         return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
 250 }
 251
 252 static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 253                 int node, struct nvme_ns *old)
 254 {
 255         struct nvme_ns *ns, *found = NULL;
 256
 257         if (list_is_singular(&head->list)) {
 258                 if (nvme_path_is_disabled(old))
 259                         return NULL;
 260                 return old;
 261         }
 262
 263         for (ns = nvme_next_ns(head, old);
 264              ns && ns != old;
 265              ns = nvme_next_ns(head, ns)) {
 266                 if (nvme_path_is_disabled(ns))
 267                         continue;
 268
 269                 if (ns->ana_state == NVME_ANA_OPTIMIZED) {
 270                         found = ns;
 271                         goto out;
 272                 }
 273                 if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
 274                         found = ns;
 275         }
 276
 277         /*
 278          * The loop above skips the current path for round-robin semantics.
 279          * Fall back to the current path if either:
 280          *  - no other optimized path found and current is optimized,
 281          *  - no other usable path found and current is usable.
 282          */
 283         if (!nvme_path_is_disabled(old) &&
 284             (old->ana_state == NVME_ANA_OPTIMIZED ||
 285              (!found && old->ana_state == NVME_ANA_NONOPTIMIZED)))
 286                 return old;
 287
 288         if (!found)
 289                 return NULL;
 290 out:
 291         rcu_assign_pointer(head->current_path[node], found);
 292         return found;
 293 }
 294
 295 static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
 296 {
 297         return ns->ctrl->state == NVME_CTRL_LIVE &&
 298                 ns->ana_state == NVME_ANA_OPTIMIZED;
 299 }
 300
 301 inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
 302 {
 303         int node = numa_node_id();
 304         struct nvme_ns *ns;
 305
 306         ns = srcu_dereference(head->current_path[node], &head->srcu);
 307         if (unlikely(!ns))
 308                 return __nvme_find_path(head, node);
 309
 310         if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
 311                 return nvme_round_robin_path(head, node, ns);
 312         if (unlikely(!nvme_path_is_optimized(ns)))
 313                 return __nvme_find_path(head, node);
 314         return ns;
 315 }
 316
 317 static bool nvme_available_path(struct nvme_ns_head *head)
 318 {
 319         struct nvme_ns *ns;
 320
 321         list_for_each_entry_rcu(ns, &head->list, siblings) {
 322                 if (test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ns->ctrl->flags))
 323                         continue;
 324                 switch (ns->ctrl->state) {
 325                 case NVME_CTRL_LIVE:
 326                 case NVME_CTRL_RESETTING:
 327                 case NVME_CTRL_CONNECTING:
 328                         /* fallthru */
 329                         return true;
 330                 default:
 331                         break;
 332                 }
 333         }
 334         return false;
 335 }
 336
 337 static void nvme_ns_head_submit_bio(struct bio *bio)
 338 {
 339         struct nvme_ns_head *head = bio->bi_bdev->bd_disk->private_data;
 340         struct device *dev = disk_to_dev(head->disk);
 341         struct nvme_ns *ns;
 342         int srcu_idx;
 343
 344         /*
 345          * The namespace might be going away and the bio might be moved to a
 346          * different queue via blk_steal_bios(), so we need to use the bio_split
 347          * pool from the original queue to allocate the bvecs from.
 348          */
 349         bio = bio_split_to_limits(bio);
 350
 351         srcu_idx = srcu_read_lock(&head->srcu);
 352         ns = nvme_find_path(head);
 353         if (likely(ns)) {
 354                 bio_set_dev(bio, ns->disk->part0);
 355                 bio->bi_opf |= REQ_NVME_MPATH;
 356                 trace_block_bio_remap(bio, disk_devt(ns->head->disk),
 357                                       bio->bi_iter.bi_sector);
 358                 submit_bio_noacct(bio);
 359         } else if (nvme_available_path(head)) {
 360                 dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
 361
 362                 spin_lock_irq(&head->requeue_lock);
 363                 bio_list_add(&head->requeue_list, bio);
 364                 spin_unlock_irq(&head->requeue_lock);
 365         } else {
 366                 dev_warn_ratelimited(dev, "no available path - failing I/O\n");
 367
 368                 bio_io_error(bio);
 369         }
 370
 371         srcu_read_unlock(&head->srcu, srcu_idx);
 372 }
 373
 374 static int nvme_ns_head_open(struct block_device *bdev, fmode_t mode)
 375 {
 376         if (!nvme_tryget_ns_head(bdev->bd_disk->private_data))
 377                 return -ENXIO;
 378         return 0;
 379 }
 380
 381 static void nvme_ns_head_release(struct gendisk *disk, fmode_t mode)
 382 {
 383         nvme_put_ns_head(disk->private_data);
 384 }
 385
 386 #ifdef CONFIG_BLK_DEV_ZONED
 387 static int nvme_ns_head_report_zones(struct gendisk *disk, sector_t sector,
 388                 unsigned int nr_zones, report_zones_cb cb, void *data)
 389 {
 390         struct nvme_ns_head *head = disk->private_data;
 391         struct nvme_ns *ns;
 392         int srcu_idx, ret = -EWOULDBLOCK;
 393
 394         srcu_idx = srcu_read_lock(&head->srcu);
 395         ns = nvme_find_path(head);
 396         if (ns)
 397                 ret = nvme_ns_report_zones(ns, sector, nr_zones, cb, data);
 398         srcu_read_unlock(&head->srcu, srcu_idx);
 399         return ret;
 400 }
 401 #else
 402 #define nvme_ns_head_report_zones       NULL
 403 #endif /* CONFIG_BLK_DEV_ZONED */
 404
 405 const struct block_device_operations nvme_ns_head_ops = {
 406         .owner          = THIS_MODULE,
 407         .submit_bio     = nvme_ns_head_submit_bio,
 408         .open           = nvme_ns_head_open,
 409         .release        = nvme_ns_head_release,
 410         .ioctl          = nvme_ns_head_ioctl,
 411         .compat_ioctl   = blkdev_compat_ptr_ioctl,
 412         .getgeo         = nvme_getgeo,
 413         .report_zones   = nvme_ns_head_report_zones,
 414         .pr_ops         = &nvme_pr_ops,
 415 };
 416
 417 static inline struct nvme_ns_head *cdev_to_ns_head(struct cdev *cdev)
 418 {
 419         return container_of(cdev, struct nvme_ns_head, cdev);
 420 }
 421
 422 static int nvme_ns_head_chr_open(struct inode *inode, struct file *file)
 423 {
 424         if (!nvme_tryget_ns_head(cdev_to_ns_head(inode->i_cdev)))
 425                 return -ENXIO;
 426         return 0;
 427 }
 428
 429 static int nvme_ns_head_chr_release(struct inode *inode, struct file *file)
 430 {
 431         nvme_put_ns_head(cdev_to_ns_head(inode->i_cdev));
 432         return 0;
 433 }
 434
 435 static const struct file_operations nvme_ns_head_chr_fops = {
 436         .owner          = THIS_MODULE,
 437         .open           = nvme_ns_head_chr_open,
 438         .release        = nvme_ns_head_chr_release,
 439         .unlocked_ioctl = nvme_ns_head_chr_ioctl,
 440         .compat_ioctl   = compat_ptr_ioctl,
 441         .uring_cmd      = nvme_ns_head_chr_uring_cmd,
 442 };
 443
 444 static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
 445 {
 446         int ret;
 447
 448         head->cdev_device.parent = &head->subsys->dev;
 449         ret = dev_set_name(&head->cdev_device, "ng%dn%d",
 450                            head->subsys->instance, head->instance);
 451         if (ret)
 452                 return ret;
 453         ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
 454                             &nvme_ns_head_chr_fops, THIS_MODULE);
 455         return ret;
 456 }
 457
 458 static void nvme_requeue_work(struct work_struct *work)
 459 {
 460         struct nvme_ns_head *head =
 461                 container_of(work, struct nvme_ns_head, requeue_work);
 462         struct bio *bio, *next;
 463
 464         spin_lock_irq(&head->requeue_lock);
 465         next = bio_list_get(&head->requeue_list);
 466         spin_unlock_irq(&head->requeue_lock);
 467
 468         while ((bio = next) != NULL) {
 469                 next = bio->bi_next;
 470                 bio->bi_next = NULL;
 471
 472                 submit_bio_noacct(bio);
 473         }
 474 }
 475
 476 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 477 {
 478         bool vwc = false;
 479
 480         mutex_init(&head->lock);
 481         bio_list_init(&head->requeue_list);
 482         spin_lock_init(&head->requeue_lock);
 483         INIT_WORK(&head->requeue_work, nvme_requeue_work);
 484
 485         /*
 486          * Add a multipath node if the subsystems supports multiple controllers.
 487          * We also do this for private namespaces as the namespace sharing flag
 488          * could change after a rescan.
 489          */
 490         if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) ||
 491             !nvme_is_unique_nsid(ctrl, head) || !multipath)
 492                 return 0;
 493
 494         head->disk = blk_alloc_disk(ctrl->numa_node);
 495         if (!head->disk)
 496                 return -ENOMEM;
 497         head->disk->fops = &nvme_ns_head_ops;
 498         head->disk->private_data = head;
 499         sprintf(head->disk->disk_name, "nvme%dn%d",
 500                         ctrl->subsys->instance, head->instance);
 501
 502         blk_queue_flag_set(QUEUE_FLAG_NONROT, head->disk->queue);
 503         blk_queue_flag_set(QUEUE_FLAG_NOWAIT, head->disk->queue);
 504         /*
 505          * This assumes all controllers that refer to a namespace either
 506          * support poll queues or not.  That is not a strict guarantee,
 507          * but if the assumption is wrong the effect is only suboptimal
 508          * performance but not correctness problem.
 509          */
 510         if (ctrl->tagset->nr_maps > HCTX_TYPE_POLL &&
 511             ctrl->tagset->map[HCTX_TYPE_POLL].nr_queues)
 512                 blk_queue_flag_set(QUEUE_FLAG_POLL, head->disk->queue);
 513
 514         /* set to a default value of 512 until the disk is validated */
 515         blk_queue_logical_block_size(head->disk->queue, 512);
 516         blk_set_stacking_limits(&head->disk->queue->limits);
 517
 518         /* we need to propagate up the VMC settings */
 519         if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
 520                 vwc = true;
 521         blk_queue_write_cache(head->disk->queue, vwc, vwc);
 522         return 0;
 523 }
 524
 525 static void nvme_mpath_set_live(struct nvme_ns *ns)
 526 {
 527         struct nvme_ns_head *head = ns->head;
 528         int rc;
 529
 530         if (!head->disk)
 531                 return;
 532
 533         /*
 534          * test_and_set_bit() is used because it is protecting against two nvme
 535          * paths simultaneously calling device_add_disk() on the same namespace
 536          * head.
 537          */
 538         if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
 539                 rc = device_add_disk(&head->subsys->dev, head->disk,
 540                                      nvme_ns_id_attr_groups);
 541                 if (rc) {
 542                         clear_bit(NVME_NSHEAD_DISK_LIVE, &ns->flags);
 543                         return;
 544                 }
 545                 nvme_add_ns_head_cdev(head);
 546         }
 547
 548         mutex_lock(&head->lock);
 549         if (nvme_path_is_optimized(ns)) {
 550                 int node, srcu_idx;
 551
 552                 srcu_idx = srcu_read_lock(&head->srcu);
 553                 for_each_node(node)
 554                         __nvme_find_path(head, node);
 555                 srcu_read_unlock(&head->srcu, srcu_idx);
 556         }
 557         mutex_unlock(&head->lock);
 558
 559         synchronize_srcu(&head->srcu);
 560         kblockd_schedule_work(&head->requeue_work);
 561 }
 562
 563 static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
 564                 int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
 565                         void *))
 566 {
 567         void *base = ctrl->ana_log_buf;
 568         size_t offset = sizeof(struct nvme_ana_rsp_hdr);
 569         int error, i;
 570
 571         lockdep_assert_held(&ctrl->ana_lock);
 572
 573         for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
 574                 struct nvme_ana_group_desc *desc = base + offset;
 575                 u32 nr_nsids;
 576                 size_t nsid_buf_size;
 577
 578                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
 579                         return -EINVAL;
 580
 581                 nr_nsids = le32_to_cpu(desc->nnsids);
 582                 nsid_buf_size = flex_array_size(desc, nsids, nr_nsids);
 583
 584                 if (WARN_ON_ONCE(desc->grpid == 0))
 585                         return -EINVAL;
 586                 if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
 587                         return -EINVAL;
 588                 if (WARN_ON_ONCE(desc->state == 0))
 589                         return -EINVAL;
 590                 if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
 591                         return -EINVAL;
 592
 593                 offset += sizeof(*desc);
 594                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
 595                         return -EINVAL;
 596
 597                 error = cb(ctrl, desc, data);
 598                 if (error)
 599                         return error;
 600
 601                 offset += nsid_buf_size;
 602         }
 603
 604         return 0;
 605 }
 606
 607 static inline bool nvme_state_is_live(enum nvme_ana_state state)
 608 {
 609         return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
 610 }
 611
 612 static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
 613                 struct nvme_ns *ns)
 614 {
 615         ns->ana_grpid = le32_to_cpu(desc->grpid);
 616         ns->ana_state = desc->state;
 617         clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
 618         /*
 619          * nvme_mpath_set_live() will trigger I/O to the multipath path device
 620          * and in turn to this path device.  However we cannot accept this I/O
 621          * if the controller is not live.  This may deadlock if called from
 622          * nvme_mpath_init_identify() and the ctrl will never complete
 623          * initialization, preventing I/O from completing.  For this case we
 624          * will reprocess the ANA log page in nvme_mpath_update() once the
 625          * controller is ready.
 626          */
 627         if (nvme_state_is_live(ns->ana_state) &&
 628             ns->ctrl->state == NVME_CTRL_LIVE)
 629                 nvme_mpath_set_live(ns);
 630 }
 631
 632 static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
 633                 struct nvme_ana_group_desc *desc, void *data)
 634 {
 635         u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
 636         unsigned *nr_change_groups = data;
 637         struct nvme_ns *ns;
 638
 639         dev_dbg(ctrl->device, "ANA group %d: %s.\n",
 640                         le32_to_cpu(desc->grpid),
 641                         nvme_ana_state_names[desc->state]);
 642
 643         if (desc->state == NVME_ANA_CHANGE)
 644                 (*nr_change_groups)++;
 645
 646         if (!nr_nsids)
 647                 return 0;
 648
 649         down_read(&ctrl->namespaces_rwsem);
 650         list_for_each_entry(ns, &ctrl->namespaces, list) {
 651                 unsigned nsid;
 652 again:
 653                 nsid = le32_to_cpu(desc->nsids[n]);
 654                 if (ns->head->ns_id < nsid)
 655                         continue;
 656                 if (ns->head->ns_id == nsid)
 657                         nvme_update_ns_ana_state(desc, ns);
 658                 if (++n == nr_nsids)
 659                         break;
 660                 if (ns->head->ns_id > nsid)
 661                         goto again;
 662         }
 663         up_read(&ctrl->namespaces_rwsem);
 664         return 0;
 665 }
 666
 667 static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
 668 {
 669         u32 nr_change_groups = 0;
 670         int error;
 671
 672         mutex_lock(&ctrl->ana_lock);
 673         error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0, NVME_CSI_NVM,
 674                         ctrl->ana_log_buf, ctrl->ana_log_size, 0);
 675         if (error) {
 676                 dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
 677                 goto out_unlock;
 678         }
 679
 680         error = nvme_parse_ana_log(ctrl, &nr_change_groups,
 681                         nvme_update_ana_state);
 682         if (error)
 683                 goto out_unlock;
 684
 685         /*
 686          * In theory we should have an ANATT timer per group as they might enter
 687          * the change state at different times.  But that is a lot of overhead
 688          * just to protect against a target that keeps entering new changes
 689          * states while never finishing previous ones.  But we'll still
 690          * eventually time out once all groups are in change state, so this
 691          * isn't a big deal.
 692          *
 693          * We also double the ANATT value to provide some slack for transports
 694          * or AEN processing overhead.
 695          */
 696         if (nr_change_groups)
 697                 mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
 698         else
 699                 del_timer_sync(&ctrl->anatt_timer);
 700 out_unlock:
 701         mutex_unlock(&ctrl->ana_lock);
 702         return error;
 703 }
 704
 705 static void nvme_ana_work(struct work_struct *work)
 706 {
 707         struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
 708
 709         if (ctrl->state != NVME_CTRL_LIVE)
 710                 return;
 711
 712         nvme_read_ana_log(ctrl);
 713 }
 714
 715 void nvme_mpath_update(struct nvme_ctrl *ctrl)
 716 {
 717         u32 nr_change_groups = 0;
 718
 719         if (!ctrl->ana_log_buf)
 720                 return;
 721
 722         mutex_lock(&ctrl->ana_lock);
 723         nvme_parse_ana_log(ctrl, &nr_change_groups, nvme_update_ana_state);
 724         mutex_unlock(&ctrl->ana_lock);
 725 }
 726
 727 static void nvme_anatt_timeout(struct timer_list *t)
 728 {
 729         struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
 730
 731         dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
 732         nvme_reset_ctrl(ctrl);
 733 }
 734
 735 void nvme_mpath_stop(struct nvme_ctrl *ctrl)
 736 {
 737         if (!nvme_ctrl_use_ana(ctrl))
 738                 return;
 739         del_timer_sync(&ctrl->anatt_timer);
 740         cancel_work_sync(&ctrl->ana_work);
 741 }
 742
 743 #define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
 744         struct device_attribute subsys_attr_##_name =   \
 745                 __ATTR(_name, _mode, _show, _store)
 746
 747 static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
 748                 struct device_attribute *attr, char *buf)
 749 {
 750         struct nvme_subsystem *subsys =
 751                 container_of(dev, struct nvme_subsystem, dev);
 752
 753         return sysfs_emit(buf, "%s\n",
 754                           nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
 755 }
 756
 757 static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
 758                 struct device_attribute *attr, const char *buf, size_t count)
 759 {
 760         struct nvme_subsystem *subsys =
 761                 container_of(dev, struct nvme_subsystem, dev);
 762         int i;
 763
 764         for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
 765                 if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
 766                         WRITE_ONCE(subsys->iopolicy, i);
 767                         return count;
 768                 }
 769         }
 770
 771         return -EINVAL;
 772 }
 773 SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
 774                       nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);
 775
 776 static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
 777                 char *buf)
 778 {
 779         return sysfs_emit(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
 780 }
 781 DEVICE_ATTR_RO(ana_grpid);
 782
 783 static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
 784                 char *buf)
 785 {
 786         struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
 787
 788         return sysfs_emit(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
 789 }
 790 DEVICE_ATTR_RO(ana_state);
 791
 792 static int nvme_lookup_ana_group_desc(struct nvme_ctrl *ctrl,
 793                 struct nvme_ana_group_desc *desc, void *data)
 794 {
 795         struct nvme_ana_group_desc *dst = data;
 796
 797         if (desc->grpid != dst->grpid)
 798                 return 0;
 799
 800         *dst = *desc;
 801         return -ENXIO; /* just break out of the loop */
 802 }
 803
 804 void nvme_mpath_add_disk(struct nvme_ns *ns, __le32 anagrpid)
 805 {
 806         if (nvme_ctrl_use_ana(ns->ctrl)) {
 807                 struct nvme_ana_group_desc desc = {
 808                         .grpid = anagrpid,
 809                         .state = 0,
 810                 };
 811
 812                 mutex_lock(&ns->ctrl->ana_lock);
 813                 ns->ana_grpid = le32_to_cpu(anagrpid);
 814                 nvme_parse_ana_log(ns->ctrl, &desc, nvme_lookup_ana_group_desc);
 815                 mutex_unlock(&ns->ctrl->ana_lock);
 816                 if (desc.state) {
 817                         /* found the group desc: update */
 818                         nvme_update_ns_ana_state(&desc, ns);
 819                 } else {
 820                         /* group desc not found: trigger a re-read */
 821                         set_bit(NVME_NS_ANA_PENDING, &ns->flags);
 822                         queue_work(nvme_wq, &ns->ctrl->ana_work);
 823                 }
 824         } else {
 825                 ns->ana_state = NVME_ANA_OPTIMIZED;
 826                 nvme_mpath_set_live(ns);
 827         }
 828
 829         if (blk_queue_stable_writes(ns->queue) && ns->head->disk)
 830                 blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
 831                                    ns->head->disk->queue);
 832 #ifdef CONFIG_BLK_DEV_ZONED
 833         if (blk_queue_is_zoned(ns->queue) && ns->head->disk)
 834                 ns->head->disk->nr_zones = ns->disk->nr_zones;
 835 #endif
 836 }
 837
 838 void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)
 839 {
 840         if (!head->disk)
 841                 return;
 842         kblockd_schedule_work(&head->requeue_work);
 843         if (test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
 844                 nvme_cdev_del(&head->cdev, &head->cdev_device);
 845                 del_gendisk(head->disk);
 846         }
 847 }
 848
 849 void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 850 {
 851         if (!head->disk)
 852                 return;
 853         blk_mark_disk_dead(head->disk);
 854         /* make sure all pending bios are cleaned up */
 855         kblockd_schedule_work(&head->requeue_work);
 856         flush_work(&head->requeue_work);
 857         put_disk(head->disk);
 858 }
 859
 860 void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl)
 861 {
 862         mutex_init(&ctrl->ana_lock);
 863         timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
 864         INIT_WORK(&ctrl->ana_work, nvme_ana_work);
 865 }
 866
 867 int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 868 {
 869         size_t max_transfer_size = ctrl->max_hw_sectors << SECTOR_SHIFT;
 870         size_t ana_log_size;
 871         int error = 0;
 872
 873         /* check if multipath is enabled and we have the capability */
 874         if (!multipath || !ctrl->subsys ||
 875             !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
 876                 return 0;
 877
 878         if (!ctrl->max_namespaces ||
 879             ctrl->max_namespaces > le32_to_cpu(id->nn)) {
 880                 dev_err(ctrl->device,
 881                         "Invalid MNAN value %u\n", ctrl->max_namespaces);
 882                 return -EINVAL;
 883         }
 884
 885         ctrl->anacap = id->anacap;
 886         ctrl->anatt = id->anatt;
 887         ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
 888         ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
 889
 890         ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
 891                 ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc) +
 892                 ctrl->max_namespaces * sizeof(__le32);
 893         if (ana_log_size > max_transfer_size) {
 894                 dev_err(ctrl->device,
 895                         "ANA log page size (%zd) larger than MDTS (%zd).\n",
 896                         ana_log_size, max_transfer_size);
 897                 dev_err(ctrl->device, "disabling ANA support.\n");
 898                 goto out_uninit;
 899         }
 900         if (ana_log_size > ctrl->ana_log_size) {
 901                 nvme_mpath_stop(ctrl);
 902                 nvme_mpath_uninit(ctrl);
 903                 ctrl->ana_log_buf = kvmalloc(ana_log_size, GFP_KERNEL);
 904                 if (!ctrl->ana_log_buf)
 905                         return -ENOMEM;
 906         }
 907         ctrl->ana_log_size = ana_log_size;
 908         error = nvme_read_ana_log(ctrl);
 909         if (error)
 910                 goto out_uninit;
 911         return 0;
 912
 913 out_uninit:
 914         nvme_mpath_uninit(ctrl);
 915         return error;
 916 }
 917
 918 void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
 919 {
 920         kvfree(ctrl->ana_log_buf);
 921         ctrl->ana_log_buf = NULL;
 922         ctrl->ana_log_size = 0;
 923 }