/* * Copyright (C) 2001 Sistina Software (UK) Limited. * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ #include "dm-core.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DM_MSG_PREFIX "table" #define MAX_DEPTH 16 #define NODE_SIZE L1_CACHE_BYTES #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t)) #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1) struct dm_table { struct mapped_device *md; enum dm_queue_mode type; /* btree table */ unsigned int depth; unsigned int counts[MAX_DEPTH]; /* in nodes */ sector_t *index[MAX_DEPTH]; unsigned int num_targets; unsigned int num_allocated; sector_t *highs; struct dm_target *targets; struct target_type *immutable_target_type; bool integrity_supported:1; bool singleton:1; unsigned integrity_added:1; /* * Indicates the rw permissions for the new logical * device. This should be a combination of FMODE_READ * and FMODE_WRITE. */ fmode_t mode; /* a list of devices used by this table */ struct list_head devices; /* events get handed up using this callback */ void (*event_fn)(void *); void *event_context; struct dm_md_mempools *mempools; struct list_head target_callbacks; }; /* * Similar to ceiling(log_size(n)) */ static unsigned int int_log(unsigned int n, unsigned int base) { int result = 0; while (n > 1) { n = dm_div_up(n, base); result++; } return result; } /* * Calculate the index of the child node of the n'th node k'th key. */ static inline unsigned int get_child(unsigned int n, unsigned int k) { return (n * CHILDREN_PER_NODE) + k; } /* * Return the n'th node of level l from table t. */ static inline sector_t *get_node(struct dm_table *t, unsigned int l, unsigned int n) { return t->index[l] + (n * KEYS_PER_NODE); } /* * Return the highest key that you could lookup from the n'th * node on level l of the btree. */ static sector_t high(struct dm_table *t, unsigned int l, unsigned int n) { for (; l < t->depth - 1; l++) n = get_child(n, CHILDREN_PER_NODE - 1); if (n >= t->counts[l]) return (sector_t) - 1; return get_node(t, l, n)[KEYS_PER_NODE - 1]; } /* * Fills in a level of the btree based on the highs of the level * below it. */ static int setup_btree_index(unsigned int l, struct dm_table *t) { unsigned int n, k; sector_t *node; for (n = 0U; n < t->counts[l]; n++) { node = get_node(t, l, n); for (k = 0U; k < KEYS_PER_NODE; k++) node[k] = high(t, l + 1, get_child(n, k)); } return 0; } void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size) { unsigned long size; void *addr; /* * Check that we're not going to overflow. */ if (nmemb > (ULONG_MAX / elem_size)) return NULL; size = nmemb * elem_size; addr = vzalloc(size); return addr; } EXPORT_SYMBOL(dm_vcalloc); /* * highs, and targets are managed as dynamic arrays during a * table load. */ static int alloc_targets(struct dm_table *t, unsigned int num) { sector_t *n_highs; struct dm_target *n_targets; /* * Allocate both the target array and offset array at once. * Append an empty entry to catch sectors beyond the end of * the device. */ n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) + sizeof(sector_t)); if (!n_highs) return -ENOMEM; n_targets = (struct dm_target *) (n_highs + num); memset(n_highs, -1, sizeof(*n_highs) * num); vfree(t->highs); t->num_allocated = num; t->highs = n_highs; t->targets = n_targets; return 0; } int dm_table_create(struct dm_table **result, fmode_t mode, unsigned num_targets, struct mapped_device *md) { struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL); if (!t) return -ENOMEM; INIT_LIST_HEAD(&t->devices); INIT_LIST_HEAD(&t->target_callbacks); if (!num_targets) num_targets = KEYS_PER_NODE; num_targets = dm_round_up(num_targets, KEYS_PER_NODE); if (!num_targets) { kfree(t); return -ENOMEM; } if (alloc_targets(t, num_targets)) { kfree(t); return -ENOMEM; } t->type = DM_TYPE_NONE; t->mode = mode; t->md = md; *result = t; return 0; } static void free_devices(struct list_head *devices, struct mapped_device *md) { struct list_head *tmp, *next; list_for_each_safe(tmp, next, devices) { struct dm_dev_internal *dd = list_entry(tmp, struct dm_dev_internal, list); DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s", dm_device_name(md), dd->dm_dev->name); dm_put_table_device(md, dd->dm_dev); kfree(dd); } } void dm_table_destroy(struct dm_table *t) { unsigned int i; if (!t) return; /* free the indexes */ if (t->depth >= 2) vfree(t->index[t->depth - 2]); /* free the targets */ for (i = 0; i < t->num_targets; i++) { struct dm_target *tgt = t->targets + i; if (tgt->type->dtr) tgt->type->dtr(tgt); dm_put_target_type(tgt->type); } vfree(t->highs); /* free the device list */ free_devices(&t->devices, t->md); dm_free_md_mempools(t->mempools); kfree(t); } /* * See if we've already got a device in the list. */ static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev) { struct dm_dev_internal *dd; list_for_each_entry (dd, l, list) if (dd->dm_dev->bdev->bd_dev == dev) return dd; return NULL; } /* * If possible, this checks an area of a destination device is invalid. */ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q; struct queue_limits *limits = data; struct block_device *bdev = dev->bdev; sector_t dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; unsigned short logical_block_size_sectors = limits->logical_block_size >> SECTOR_SHIFT; char b[BDEVNAME_SIZE]; /* * Some devices exist without request functions, * such as loop devices not yet bound to backing files. * Forbid the use of such devices. */ q = bdev_get_queue(bdev); if (!q || !q->make_request_fn) { DMWARN("%s: %s is not yet initialised: " "start=%llu, len=%llu, dev_size=%llu", dm_device_name(ti->table->md), bdevname(bdev, b), (unsigned long long)start, (unsigned long long)len, (unsigned long long)dev_size); return 1; } if (!dev_size) return 0; if ((start >= dev_size) || (start + len > dev_size)) { DMWARN("%s: %s too small for target: " "start=%llu, len=%llu, dev_size=%llu", dm_device_name(ti->table->md), bdevname(bdev, b), (unsigned long long)start, (unsigned long long)len, (unsigned long long)dev_size); return 1; } /* * If the target is mapped to zoned block device(s), check * that the zones are not partially mapped. */ if (bdev_zoned_model(bdev) != BLK_ZONED_NONE) { unsigned int zone_sectors = bdev_zone_sectors(bdev); if (start & (zone_sectors - 1)) { DMWARN("%s: start=%llu not aligned to h/w zone size %u of %s", dm_device_name(ti->table->md), (unsigned long long)start, zone_sectors, bdevname(bdev, b)); return 1; } /* * Note: The last zone of a zoned block device may be smaller * than other zones. So for a target mapping the end of a * zoned block device with such a zone, len would not be zone * aligned. We do not allow such last smaller zone to be part * of the mapping here to ensure that mappings with multiple * devices do not end up with a smaller zone in the middle of * the sector range. */ if (len & (zone_sectors - 1)) { DMWARN("%s: len=%llu not aligned to h/w zone size %u of %s", dm_device_name(ti->table->md), (unsigned long long)len, zone_sectors, bdevname(bdev, b)); return 1; } } if (logical_block_size_sectors <= 1) return 0; if (start & (logical_block_size_sectors - 1)) { DMWARN("%s: start=%llu not aligned to h/w " "logical block size %u of %s", dm_device_name(ti->table->md), (unsigned long long)start, limits->logical_block_size, bdevname(bdev, b)); return 1; } if (len & (logical_block_size_sectors - 1)) { DMWARN("%s: len=%llu not aligned to h/w " "logical block size %u of %s", dm_device_name(ti->table->md), (unsigned long long)len, limits->logical_block_size, bdevname(bdev, b)); return 1; } return 0; } /* * This upgrades the mode on an already open dm_dev, being * careful to leave things as they were if we fail to reopen the * device and not to touch the existing bdev field in case * it is accessed concurrently inside dm_table_any_congested(). */ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode, struct mapped_device *md) { int r; struct dm_dev *old_dev, *new_dev; old_dev = dd->dm_dev; r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev, dd->dm_dev->mode | new_mode, &new_dev); if (r) return r; dd->dm_dev = new_dev; dm_put_table_device(md, old_dev); return 0; } /* * Convert the path to a device */ dev_t dm_get_dev_t(const char *path) { dev_t dev; struct block_device *bdev; bdev = lookup_bdev(path); if (IS_ERR(bdev)) dev = name_to_dev_t(path); else { dev = bdev->bd_dev; bdput(bdev); } return dev; } EXPORT_SYMBOL_GPL(dm_get_dev_t); /* * Add a device to the list, or just increment the usage count if * it's already present. */ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, struct dm_dev **result) { int r; dev_t dev; struct dm_dev_internal *dd; struct dm_table *t = ti->table; BUG_ON(!t); dev = dm_get_dev_t(path); if (!dev) return -ENODEV; dd = find_device(&t->devices, dev); if (!dd) { dd = kmalloc(sizeof(*dd), GFP_KERNEL); if (!dd) return -ENOMEM; if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) { kfree(dd); return r; } refcount_set(&dd->count, 1); list_add(&dd->list, &t->devices); goto out; } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) { r = upgrade_mode(dd, mode, t->md); if (r) return r; } refcount_inc(&dd->count); out: *result = dd->dm_dev; return 0; } EXPORT_SYMBOL(dm_get_device); static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct queue_limits *limits = data; struct block_device *bdev = dev->bdev; struct request_queue *q = bdev_get_queue(bdev); char b[BDEVNAME_SIZE]; if (unlikely(!q)) { DMWARN("%s: Cannot set limits for nonexistent device %s", dm_device_name(ti->table->md), bdevname(bdev, b)); return 0; } if (bdev_stack_limits(limits, bdev, start) < 0) DMWARN("%s: adding target device %s caused an alignment inconsistency: " "physical_block_size=%u, logical_block_size=%u, " "alignment_offset=%u, start=%llu", dm_device_name(ti->table->md), bdevname(bdev, b), q->limits.physical_block_size, q->limits.logical_block_size, q->limits.alignment_offset, (unsigned long long) start << SECTOR_SHIFT); limits->zoned = blk_queue_zoned_model(q); return 0; } /* * Decrement a device's use count and remove it if necessary. */ void dm_put_device(struct dm_target *ti, struct dm_dev *d) { int found = 0; struct list_head *devices = &ti->table->devices; struct dm_dev_internal *dd; list_for_each_entry(dd, devices, list) { if (dd->dm_dev == d) { found = 1; break; } } if (!found) { DMWARN("%s: device %s not in table devices list", dm_device_name(ti->table->md), d->name); return; } if (refcount_dec_and_test(&dd->count)) { dm_put_table_device(ti->table->md, d); list_del(&dd->list); kfree(dd); } } EXPORT_SYMBOL(dm_put_device); /* * Checks to see if the target joins onto the end of the table. */ static int adjoin(struct dm_table *table, struct dm_target *ti) { struct dm_target *prev; if (!table->num_targets) return !ti->begin; prev = &table->targets[table->num_targets - 1]; return (ti->begin == (prev->begin + prev->len)); } /* * Used to dynamically allocate the arg array. * * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must * process messages even if some device is suspended. These messages have a * small fixed number of arguments. * * On the other hand, dm-switch needs to process bulk data using messages and * excessive use of GFP_NOIO could cause trouble. */ static char **realloc_argv(unsigned *size, char **old_argv) { char **argv; unsigned new_size; gfp_t gfp; if (*size) { new_size = *size * 2; gfp = GFP_KERNEL; } else { new_size = 8; gfp = GFP_NOIO; } argv = kmalloc_array(new_size, sizeof(*argv), gfp); if (argv) { memcpy(argv, old_argv, *size * sizeof(*argv)); *size = new_size; } kfree(old_argv); return argv; } /* * Destructively splits up the argument list to pass to ctr. */ int dm_split_args(int *argc, char ***argvp, char *input) { char *start, *end = input, *out, **argv = NULL; unsigned array_size = 0; *argc = 0; if (!input) { *argvp = NULL; return 0; } argv = realloc_argv(&array_size, argv); if (!argv) return -ENOMEM; while (1) { /* Skip whitespace */ start = skip_spaces(end); if (!*start) break; /* success, we hit the end */ /* 'out' is used to remove any back-quotes */ end = out = start; while (*end) { /* Everything apart from '\0' can be quoted */ if (*end == '\\' && *(end + 1)) { *out++ = *(end + 1); end += 2; continue; } if (isspace(*end)) break; /* end of token */ *out++ = *end++; } /* have we already filled the array ? */ if ((*argc + 1) > array_size) { argv = realloc_argv(&array_size, argv); if (!argv) return -ENOMEM; } /* we know this is whitespace */ if (*end) end++; /* terminate the string and put it in the array */ *out = '\0'; argv[*argc] = start; (*argc)++; } *argvp = argv; return 0; } /* * Impose necessary and sufficient conditions on a devices's table such * that any incoming bio which respects its logical_block_size can be * processed successfully. If it falls across the boundary between * two or more targets, the size of each piece it gets split into must * be compatible with the logical_block_size of the target processing it. */ static int validate_hardware_logical_block_alignment(struct dm_table *table, struct queue_limits *limits) { /* * This function uses arithmetic modulo the logical_block_size * (in units of 512-byte sectors). */ unsigned short device_logical_block_size_sects = limits->logical_block_size >> SECTOR_SHIFT; /* * Offset of the start of the next table entry, mod logical_block_size. */ unsigned short next_target_start = 0; /* * Given an aligned bio that extends beyond the end of a * target, how many sectors must the next target handle? */ unsigned short remaining = 0; struct dm_target *uninitialized_var(ti); struct queue_limits ti_limits; unsigned i; /* * Check each entry in the table in turn. */ for (i = 0; i < dm_table_get_num_targets(table); i++) { ti = dm_table_get_target(table, i); blk_set_stacking_limits(&ti_limits); /* combine all target devices' limits */ if (ti->type->iterate_devices) ti->type->iterate_devices(ti, dm_set_device_limits, &ti_limits); /* * If the remaining sectors fall entirely within this * table entry are they compatible with its logical_block_size? */ if (remaining < ti->len && remaining & ((ti_limits.logical_block_size >> SECTOR_SHIFT) - 1)) break; /* Error */ next_target_start = (unsigned short) ((next_target_start + ti->len) & (device_logical_block_size_sects - 1)); remaining = next_target_start ? device_logical_block_size_sects - next_target_start : 0; } if (remaining) { DMWARN("%s: table line %u (start sect %llu len %llu) " "not aligned to h/w logical block size %u", dm_device_name(table->md), i, (unsigned long long) ti->begin, (unsigned long long) ti->len, limits->logical_block_size); return -EINVAL; } return 0; } int dm_table_add_target(struct dm_table *t, const char *type, sector_t start, sector_t len, char *params) { int r = -EINVAL, argc; char **argv; struct dm_target *tgt; if (t->singleton) { DMERR("%s: target type %s must appear alone in table", dm_device_name(t->md), t->targets->type->name); return -EINVAL; } BUG_ON(t->num_targets >= t->num_allocated); tgt = t->targets + t->num_targets; memset(tgt, 0, sizeof(*tgt)); if (!len) { DMERR("%s: zero-length target", dm_device_name(t->md)); return -EINVAL; } tgt->type = dm_get_target_type(type); if (!tgt->type) { DMERR("%s: %s: unknown target type", dm_device_name(t->md), type); return -EINVAL; } if (dm_target_needs_singleton(tgt->type)) { if (t->num_targets) { tgt->error = "singleton target type must appear alone in table"; goto bad; } t->singleton = true; } if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) { tgt->error = "target type may not be included in a read-only table"; goto bad; } if (t->immutable_target_type) { if (t->immutable_target_type != tgt->type) { tgt->error = "immutable target type cannot be mixed with other target types"; goto bad; } } else if (dm_target_is_immutable(tgt->type)) { if (t->num_targets) { tgt->error = "immutable target type cannot be mixed with other target types"; goto bad; } t->immutable_target_type = tgt->type; } if (dm_target_has_integrity(tgt->type)) t->integrity_added = 1; tgt->table = t; tgt->begin = start; tgt->len = len; tgt->error = "Unknown error"; /* * Does this target adjoin the previous one ? */ if (!adjoin(t, tgt)) { tgt->error = "Gap in table"; goto bad; } r = dm_split_args(&argc, &argv, params); if (r) { tgt->error = "couldn't split parameters (insufficient memory)"; goto bad; } r = tgt->type->ctr(tgt, argc, argv); kfree(argv); if (r) goto bad; t->highs[t->num_targets++] = tgt->begin + tgt->len - 1; if (!tgt->num_discard_bios && tgt->discards_supported) DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.", dm_device_name(t->md), type); return 0; bad: DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error); dm_put_target_type(tgt->type); return r; } /* * Target argument parsing helpers. */ static int validate_next_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set, unsigned *value, char **error, unsigned grouped) { const char *arg_str = dm_shift_arg(arg_set); char dummy; if (!arg_str || (sscanf(arg_str, "%u%c", value, &dummy) != 1) || (*value < arg->min) || (*value > arg->max) || (grouped && arg_set->argc < *value)) { *error = arg->error; return -EINVAL; } return 0; } int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set, unsigned *value, char **error) { return validate_next_arg(arg, arg_set, value, error, 0); } EXPORT_SYMBOL(dm_read_arg); int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set, unsigned *value, char **error) { return validate_next_arg(arg, arg_set, value, error, 1); } EXPORT_SYMBOL(dm_read_arg_group); const char *dm_shift_arg(struct dm_arg_set *as) { char *r; if (as->argc) { as->argc--; r = *as->argv; as->argv++; return r; } return NULL; } EXPORT_SYMBOL(dm_shift_arg); void dm_consume_args(struct dm_arg_set *as, unsigned num_args) { BUG_ON(as->argc < num_args); as->argc -= num_args; as->argv += num_args; } EXPORT_SYMBOL(dm_consume_args); static bool __table_type_bio_based(enum dm_queue_mode table_type) { return (table_type == DM_TYPE_BIO_BASED || table_type == DM_TYPE_DAX_BIO_BASED || table_type == DM_TYPE_NVME_BIO_BASED); } static bool __table_type_request_based(enum dm_queue_mode table_type) { return table_type == DM_TYPE_REQUEST_BASED; } void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type) { t->type = type; } EXPORT_SYMBOL_GPL(dm_table_set_type); static int device_supports_dax(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { return bdev_dax_supported(dev->bdev, PAGE_SIZE); } static bool dm_table_supports_dax(struct dm_table *t) { struct dm_target *ti; unsigned i; /* Ensure that all targets support DAX. */ for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->type->direct_access) return false; if (!ti->type->iterate_devices || !ti->type->iterate_devices(ti, device_supports_dax, NULL)) return false; } return true; } static bool dm_table_does_not_support_partial_completion(struct dm_table *t); struct verify_rq_based_data { unsigned sq_count; unsigned mq_count; }; static int device_is_rq_based(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); struct verify_rq_based_data *v = data; if (q->mq_ops) v->mq_count++; else v->sq_count++; return queue_is_rq_based(q); } static int dm_table_determine_type(struct dm_table *t) { unsigned i; unsigned bio_based = 0, request_based = 0, hybrid = 0; struct verify_rq_based_data v = {.sq_count = 0, .mq_count = 0}; struct dm_target *tgt; struct list_head *devices = dm_table_get_devices(t); enum dm_queue_mode live_md_type = dm_get_md_type(t->md); if (t->type != DM_TYPE_NONE) { /* target already set the table's type */ if (t->type == DM_TYPE_BIO_BASED) { /* possibly upgrade to a variant of bio-based */ goto verify_bio_based; } BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED); BUG_ON(t->type == DM_TYPE_NVME_BIO_BASED); goto verify_rq_based; } for (i = 0; i < t->num_targets; i++) { tgt = t->targets + i; if (dm_target_hybrid(tgt)) hybrid = 1; else if (dm_target_request_based(tgt)) request_based = 1; else bio_based = 1; if (bio_based && request_based) { DMERR("Inconsistent table: different target types" " can't be mixed up"); return -EINVAL; } } if (hybrid && !bio_based && !request_based) { /* * The targets can work either way. * Determine the type from the live device. * Default to bio-based if device is new. */ if (__table_type_request_based(live_md_type)) request_based = 1; else bio_based = 1; } if (bio_based) { verify_bio_based: /* We must use this table as bio-based */ t->type = DM_TYPE_BIO_BASED; if (dm_table_supports_dax(t) || (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED)) { t->type = DM_TYPE_DAX_BIO_BASED; } else { /* Check if upgrading to NVMe bio-based is valid or required */ tgt = dm_table_get_immutable_target(t); if (tgt && !tgt->max_io_len && dm_table_does_not_support_partial_completion(t)) { t->type = DM_TYPE_NVME_BIO_BASED; goto verify_rq_based; /* must be stacked directly on NVMe (blk-mq) */ } else if (list_empty(devices) && live_md_type == DM_TYPE_NVME_BIO_BASED) { t->type = DM_TYPE_NVME_BIO_BASED; } } return 0; } BUG_ON(!request_based); /* No targets in this table */ t->type = DM_TYPE_REQUEST_BASED; verify_rq_based: /* * Request-based dm supports only tables that have a single target now. * To support multiple targets, request splitting support is needed, * and that needs lots of changes in the block-layer. * (e.g. request completion process for partial completion.) */ if (t->num_targets > 1) { DMERR("%s DM doesn't support multiple targets", t->type == DM_TYPE_NVME_BIO_BASED ? "nvme bio-based" : "request-based"); return -EINVAL; } if (list_empty(devices)) { int srcu_idx; struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx); /* inherit live table's type */ if (live_table) t->type = live_table->type; dm_put_live_table(t->md, srcu_idx); return 0; } tgt = dm_table_get_immutable_target(t); if (!tgt) { DMERR("table load rejected: immutable target is required"); return -EINVAL; } else if (tgt->max_io_len) { DMERR("table load rejected: immutable target that splits IO is not supported"); return -EINVAL; } /* Non-request-stackable devices can't be used for request-based dm */ if (!tgt->type->iterate_devices || !tgt->type->iterate_devices(tgt, device_is_rq_based, &v)) { DMERR("table load rejected: including non-request-stackable devices"); return -EINVAL; } if (v.sq_count > 0) { DMERR("table load rejected: not all devices are blk-mq request-stackable"); return -EINVAL; } return 0; } enum dm_queue_mode dm_table_get_type(struct dm_table *t) { return t->type; } struct target_type *dm_table_get_immutable_target_type(struct dm_table *t) { return t->immutable_target_type; } struct dm_target *dm_table_get_immutable_target(struct dm_table *t) { /* Immutable target is implicitly a singleton */ if (t->num_targets > 1 || !dm_target_is_immutable(t->targets[0].type)) return NULL; return t->targets; } struct dm_target *dm_table_get_wildcard_target(struct dm_table *t) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (dm_target_is_wildcard(ti->type)) return ti; } return NULL; } bool dm_table_bio_based(struct dm_table *t) { return __table_type_bio_based(dm_table_get_type(t)); } bool dm_table_request_based(struct dm_table *t) { return __table_type_request_based(dm_table_get_type(t)); } static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md) { enum dm_queue_mode type = dm_table_get_type(t); unsigned per_io_data_size = 0; unsigned min_pool_size = 0; struct dm_target *ti; unsigned i; if (unlikely(type == DM_TYPE_NONE)) { DMWARN("no table type is set, can't allocate mempools"); return -EINVAL; } if (__table_type_bio_based(type)) for (i = 0; i < t->num_targets; i++) { ti = t->targets + i; per_io_data_size = max(per_io_data_size, ti->per_io_data_size); min_pool_size = max(min_pool_size, ti->num_flush_bios); } t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_io_data_size, min_pool_size); if (!t->mempools) return -ENOMEM; return 0; } void dm_table_free_md_mempools(struct dm_table *t) { dm_free_md_mempools(t->mempools); t->mempools = NULL; } struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t) { return t->mempools; } static int setup_indexes(struct dm_table *t) { int i; unsigned int total = 0; sector_t *indexes; /* allocate the space for *all* the indexes */ for (i = t->depth - 2; i >= 0; i--) { t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE); total += t->counts[i]; } indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE); if (!indexes) return -ENOMEM; /* set up internal nodes, bottom-up */ for (i = t->depth - 2; i >= 0; i--) { t->index[i] = indexes; indexes += (KEYS_PER_NODE * t->counts[i]); setup_btree_index(i, t); } return 0; } /* * Builds the btree to index the map. */ static int dm_table_build_index(struct dm_table *t) { int r = 0; unsigned int leaf_nodes; /* how many indexes will the btree have ? */ leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE); t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE); /* leaf layer has already been set up */ t->counts[t->depth - 1] = leaf_nodes; t->index[t->depth - 1] = t->highs; if (t->depth >= 2) r = setup_indexes(t); return r; } static bool integrity_profile_exists(struct gendisk *disk) { return !!blk_get_integrity(disk); } /* * Get a disk whose integrity profile reflects the table's profile. * Returns NULL if integrity support was inconsistent or unavailable. */ static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t) { struct list_head *devices = dm_table_get_devices(t); struct dm_dev_internal *dd = NULL; struct gendisk *prev_disk = NULL, *template_disk = NULL; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { struct dm_target *ti = dm_table_get_target(t, i); if (!dm_target_passes_integrity(ti->type)) goto no_integrity; } list_for_each_entry(dd, devices, list) { template_disk = dd->dm_dev->bdev->bd_disk; if (!integrity_profile_exists(template_disk)) goto no_integrity; else if (prev_disk && blk_integrity_compare(prev_disk, template_disk) < 0) goto no_integrity; prev_disk = template_disk; } return template_disk; no_integrity: if (prev_disk) DMWARN("%s: integrity not set: %s and %s profile mismatch", dm_device_name(t->md), prev_disk->disk_name, template_disk->disk_name); return NULL; } /* * Register the mapped device for blk_integrity support if the * underlying devices have an integrity profile. But all devices may * not have matching profiles (checking all devices isn't reliable * during table load because this table may use other DM device(s) which * must be resumed before they will have an initialized integity * profile). Consequently, stacked DM devices force a 2 stage integrity * profile validation: First pass during table load, final pass during * resume. */ static int dm_table_register_integrity(struct dm_table *t) { struct mapped_device *md = t->md; struct gendisk *template_disk = NULL; /* If target handles integrity itself do not register it here. */ if (t->integrity_added) return 0; template_disk = dm_table_get_integrity_disk(t); if (!template_disk) return 0; if (!integrity_profile_exists(dm_disk(md))) { t->integrity_supported = true; /* * Register integrity profile during table load; we can do * this because the final profile must match during resume. */ blk_integrity_register(dm_disk(md), blk_get_integrity(template_disk)); return 0; } /* * If DM device already has an initialized integrity * profile the new profile should not conflict. */ if (blk_integrity_compare(dm_disk(md), template_disk) < 0) { DMWARN("%s: conflict with existing integrity profile: " "%s profile mismatch", dm_device_name(t->md), template_disk->disk_name); return 1; } /* Preserve existing integrity profile */ t->integrity_supported = true; return 0; } /* * Prepares the table for use by building the indices, * setting the type, and allocating mempools. */ int dm_table_complete(struct dm_table *t) { int r; r = dm_table_determine_type(t); if (r) { DMERR("unable to determine table type"); return r; } r = dm_table_build_index(t); if (r) { DMERR("unable to build btrees"); return r; } r = dm_table_register_integrity(t); if (r) { DMERR("could not register integrity profile."); return r; } r = dm_table_alloc_md_mempools(t, t->md); if (r) DMERR("unable to allocate mempools"); return r; } static DEFINE_MUTEX(_event_lock); void dm_table_event_callback(struct dm_table *t, void (*fn)(void *), void *context) { mutex_lock(&_event_lock); t->event_fn = fn; t->event_context = context; mutex_unlock(&_event_lock); } void dm_table_event(struct dm_table *t) { /* * You can no longer call dm_table_event() from interrupt * context, use a bottom half instead. */ BUG_ON(in_interrupt()); mutex_lock(&_event_lock); if (t->event_fn) t->event_fn(t->event_context); mutex_unlock(&_event_lock); } EXPORT_SYMBOL(dm_table_event); sector_t dm_table_get_size(struct dm_table *t) { return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0; } EXPORT_SYMBOL(dm_table_get_size); struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index) { if (index >= t->num_targets) return NULL; return t->targets + index; } /* * Search the btree for the correct target. * * Caller should check returned pointer with dm_target_is_valid() * to trap I/O beyond end of device. */ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector) { unsigned int l, n = 0, k = 0; sector_t *node; for (l = 0; l < t->depth; l++) { n = get_child(n, k); node = get_node(t, l, n); for (k = 0; k < KEYS_PER_NODE; k++) if (node[k] >= sector) break; } return &t->targets[(KEYS_PER_NODE * n) + k]; } static int count_device(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { unsigned *num_devices = data; (*num_devices)++; return 0; } /* * Check whether a table has no data devices attached using each * target's iterate_devices method. * Returns false if the result is unknown because a target doesn't * support iterate_devices. */ bool dm_table_has_no_data_devices(struct dm_table *table) { struct dm_target *ti; unsigned i, num_devices; for (i = 0; i < dm_table_get_num_targets(table); i++) { ti = dm_table_get_target(table, i); if (!ti->type->iterate_devices) return false; num_devices = 0; ti->type->iterate_devices(ti, count_device, &num_devices); if (num_devices) return false; } return true; } static int device_is_zoned_model(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); enum blk_zoned_model *zoned_model = data; return q && blk_queue_zoned_model(q) == *zoned_model; } static bool dm_table_supports_zoned_model(struct dm_table *t, enum blk_zoned_model zoned_model) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (zoned_model == BLK_ZONED_HM && !dm_target_supports_zoned_hm(ti->type)) return false; if (!ti->type->iterate_devices || !ti->type->iterate_devices(ti, device_is_zoned_model, &zoned_model)) return false; } return true; } static int device_matches_zone_sectors(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); unsigned int *zone_sectors = data; return q && blk_queue_zone_sectors(q) == *zone_sectors; } static bool dm_table_matches_zone_sectors(struct dm_table *t, unsigned int zone_sectors) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->type->iterate_devices || !ti->type->iterate_devices(ti, device_matches_zone_sectors, &zone_sectors)) return false; } return true; } static int validate_hardware_zoned_model(struct dm_table *table, enum blk_zoned_model zoned_model, unsigned int zone_sectors) { if (zoned_model == BLK_ZONED_NONE) return 0; if (!dm_table_supports_zoned_model(table, zoned_model)) { DMERR("%s: zoned model is not consistent across all devices", dm_device_name(table->md)); return -EINVAL; } /* Check zone size validity and compatibility */ if (!zone_sectors || !is_power_of_2(zone_sectors)) return -EINVAL; if (!dm_table_matches_zone_sectors(table, zone_sectors)) { DMERR("%s: zone sectors is not consistent across all devices", dm_device_name(table->md)); return -EINVAL; } return 0; } /* * Establish the new table's queue_limits and validate them. */ int dm_calculate_queue_limits(struct dm_table *table, struct queue_limits *limits) { struct dm_target *ti; struct queue_limits ti_limits; unsigned i; enum blk_zoned_model zoned_model = BLK_ZONED_NONE; unsigned int zone_sectors = 0; blk_set_stacking_limits(limits); for (i = 0; i < dm_table_get_num_targets(table); i++) { blk_set_stacking_limits(&ti_limits); ti = dm_table_get_target(table, i); if (!ti->type->iterate_devices) goto combine_limits; /* * Combine queue limits of all the devices this target uses. */ ti->type->iterate_devices(ti, dm_set_device_limits, &ti_limits); if (zoned_model == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) { /* * After stacking all limits, validate all devices * in table support this zoned model and zone sectors. */ zoned_model = ti_limits.zoned; zone_sectors = ti_limits.chunk_sectors; } /* Set I/O hints portion of queue limits */ if (ti->type->io_hints) ti->type->io_hints(ti, &ti_limits); /* * Check each device area is consistent with the target's * overall queue limits. */ if (ti->type->iterate_devices(ti, device_area_is_invalid, &ti_limits)) return -EINVAL; combine_limits: /* * Merge this target's queue limits into the overall limits * for the table. */ if (blk_stack_limits(limits, &ti_limits, 0) < 0) DMWARN("%s: adding target device " "(start sect %llu len %llu) " "caused an alignment inconsistency", dm_device_name(table->md), (unsigned long long) ti->begin, (unsigned long long) ti->len); /* * FIXME: this should likely be moved to blk_stack_limits(), would * also eliminate limits->zoned stacking hack in dm_set_device_limits() */ if (limits->zoned == BLK_ZONED_NONE && ti_limits.zoned != BLK_ZONED_NONE) { /* * By default, the stacked limits zoned model is set to * BLK_ZONED_NONE in blk_set_stacking_limits(). Update * this model using the first target model reported * that is not BLK_ZONED_NONE. This will be either the * first target device zoned model or the model reported * by the target .io_hints. */ limits->zoned = ti_limits.zoned; } } /* * Verify that the zoned model and zone sectors, as determined before * any .io_hints override, are the same across all devices in the table. * - this is especially relevant if .io_hints is emulating a disk-managed * zoned model (aka BLK_ZONED_NONE) on host-managed zoned block devices. * BUT... */ if (limits->zoned != BLK_ZONED_NONE) { /* * ...IF the above limits stacking determined a zoned model * validate that all of the table's devices conform to it. */ zoned_model = limits->zoned; zone_sectors = limits->chunk_sectors; } if (validate_hardware_zoned_model(table, zoned_model, zone_sectors)) return -EINVAL; return validate_hardware_logical_block_alignment(table, limits); } /* * Verify that all devices have an integrity profile that matches the * DM device's registered integrity profile. If the profiles don't * match then unregister the DM device's integrity profile. */ static void dm_table_verify_integrity(struct dm_table *t) { struct gendisk *template_disk = NULL; if (t->integrity_added) return; if (t->integrity_supported) { /* * Verify that the original integrity profile * matches all the devices in this table. */ template_disk = dm_table_get_integrity_disk(t); if (template_disk && blk_integrity_compare(dm_disk(t->md), template_disk) >= 0) return; } if (integrity_profile_exists(dm_disk(t->md))) { DMWARN("%s: unable to establish an integrity profile", dm_device_name(t->md)); blk_integrity_unregister(dm_disk(t->md)); } } static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { unsigned long flush = (unsigned long) data; struct request_queue *q = bdev_get_queue(dev->bdev); return q && (q->queue_flags & flush); } static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush) { struct dm_target *ti; unsigned i; /* * Require at least one underlying device to support flushes. * t->devices includes internal dm devices such as mirror logs * so we need to use iterate_devices here, which targets * supporting flushes must provide. */ for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->num_flush_bios) continue; if (ti->flush_supported) return true; if (ti->type->iterate_devices && ti->type->iterate_devices(ti, device_flush_capable, (void *) flush)) return true; } return false; } static int device_dax_write_cache_enabled(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct dax_device *dax_dev = dev->dax_dev; if (!dax_dev) return false; if (dax_write_cache_enabled(dax_dev)) return true; return false; } static int dm_table_supports_dax_write_cache(struct dm_table *t) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (ti->type->iterate_devices && ti->type->iterate_devices(ti, device_dax_write_cache_enabled, NULL)) return true; } return false; } static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && blk_queue_nonrot(q); } static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && !blk_queue_add_random(q); } static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags); } static bool dm_table_all_devices_attribute(struct dm_table *t, iterate_devices_callout_fn func) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->type->iterate_devices || !ti->type->iterate_devices(ti, func, NULL)) return false; } return true; } static int device_no_partial_completion(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { char b[BDEVNAME_SIZE]; /* For now, NVMe devices are the only devices of this class */ return (strncmp(bdevname(dev->bdev, b), "nvme", 4) == 0); } static bool dm_table_does_not_support_partial_completion(struct dm_table *t) { return dm_table_all_devices_attribute(t, device_no_partial_completion); } static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && !q->limits.max_write_same_sectors; } static bool dm_table_supports_write_same(struct dm_table *t) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->num_write_same_bios) return false; if (!ti->type->iterate_devices || ti->type->iterate_devices(ti, device_not_write_same_capable, NULL)) return false; } return true; } static int device_not_write_zeroes_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && !q->limits.max_write_zeroes_sectors; } static bool dm_table_supports_write_zeroes(struct dm_table *t) { struct dm_target *ti; unsigned i = 0; while (i < dm_table_get_num_targets(t)) { ti = dm_table_get_target(t, i++); if (!ti->num_write_zeroes_bios) return false; if (!ti->type->iterate_devices || ti->type->iterate_devices(ti, device_not_write_zeroes_capable, NULL)) return false; } return true; } static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && !blk_queue_discard(q); } static bool dm_table_supports_discards(struct dm_table *t) { struct dm_target *ti; unsigned i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->num_discard_bios) return false; /* * Either the target provides discard support (as implied by setting * 'discards_supported') or it relies on _all_ data devices having * discard support. */ if (!ti->discards_supported && (!ti->type->iterate_devices || ti->type->iterate_devices(ti, device_not_discard_capable, NULL))) return false; } return true; } static int device_not_secure_erase_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { struct request_queue *q = bdev_get_queue(dev->bdev); return q && !blk_queue_secure_erase(q); } static bool dm_table_supports_secure_erase(struct dm_table *t) { struct dm_target *ti; unsigned int i; for (i = 0; i < dm_table_get_num_targets(t); i++) { ti = dm_table_get_target(t, i); if (!ti->num_secure_erase_bios) return false; if (!ti->type->iterate_devices || ti->type->iterate_devices(ti, device_not_secure_erase_capable, NULL)) return false; } return true; } void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *limits) { bool wc = false, fua = false; /* * Copy table's limits to the DM device's request_queue */ q->limits = *limits; if (!dm_table_supports_discards(t)) { blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); /* Must also clear discard limits... */ q->limits.max_discard_sectors = 0; q->limits.max_hw_discard_sectors = 0; q->limits.discard_granularity = 0; q->limits.discard_alignment = 0; q->limits.discard_misaligned = 0; } else blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); if (dm_table_supports_secure_erase(t)) blk_queue_flag_set(QUEUE_FLAG_SECERASE, q); if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) { wc = true; if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA))) fua = true; } blk_queue_write_cache(q, wc, fua); if (dm_table_supports_dax(t)) blk_queue_flag_set(QUEUE_FLAG_DAX, q); else blk_queue_flag_clear(QUEUE_FLAG_DAX, q); if (dm_table_supports_dax_write_cache(t)) dax_write_cache(t->md->dax_dev, true); /* Ensure that all underlying devices are non-rotational. */ if (dm_table_all_devices_attribute(t, device_is_nonrot)) blk_queue_flag_set(QUEUE_FLAG_NONROT, q); else blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); if (!dm_table_supports_write_same(t)) q->limits.max_write_same_sectors = 0; if (!dm_table_supports_write_zeroes(t)) q->limits.max_write_zeroes_sectors = 0; if (dm_table_all_devices_attribute(t, queue_supports_sg_merge)) blk_queue_flag_clear(QUEUE_FLAG_NO_SG_MERGE, q); else blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q); dm_table_verify_integrity(t); /* * Determine whether or not this queue's I/O timings contribute * to the entropy pool, Only request-based targets use this. * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not * have it set. */ if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random)) blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q); } unsigned int dm_table_get_num_targets(struct dm_table *t) { return t->num_targets; } struct list_head *dm_table_get_devices(struct dm_table *t) { return &t->devices; } fmode_t dm_table_get_mode(struct dm_table *t) { return t->mode; } EXPORT_SYMBOL(dm_table_get_mode); enum suspend_mode { PRESUSPEND, PRESUSPEND_UNDO, POSTSUSPEND, }; static void suspend_targets(struct dm_table *t, enum suspend_mode mode) { int i = t->num_targets; struct dm_target *ti = t->targets; lockdep_assert_held(&t->md->suspend_lock); while (i--) { switch (mode) { case PRESUSPEND: if (ti->type->presuspend) ti->type->presuspend(ti); break; case PRESUSPEND_UNDO: if (ti->type->presuspend_undo) ti->type->presuspend_undo(ti); break; case POSTSUSPEND: if (ti->type->postsuspend) ti->type->postsuspend(ti); break; } ti++; } } void dm_table_presuspend_targets(struct dm_table *t) { if (!t) return; suspend_targets(t, PRESUSPEND); } void dm_table_presuspend_undo_targets(struct dm_table *t) { if (!t) return; suspend_targets(t, PRESUSPEND_UNDO); } void dm_table_postsuspend_targets(struct dm_table *t) { if (!t) return; suspend_targets(t, POSTSUSPEND); } int dm_table_resume_targets(struct dm_table *t) { int i, r = 0; lockdep_assert_held(&t->md->suspend_lock); for (i = 0; i < t->num_targets; i++) { struct dm_target *ti = t->targets + i; if (!ti->type->preresume) continue; r = ti->type->preresume(ti); if (r) { DMERR("%s: %s: preresume failed, error = %d", dm_device_name(t->md), ti->type->name, r); return r; } } for (i = 0; i < t->num_targets; i++) { struct dm_target *ti = t->targets + i; if (ti->type->resume) ti->type->resume(ti); } return 0; } void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb) { list_add(&cb->list, &t->target_callbacks); } EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks); int dm_table_any_congested(struct dm_table *t, int bdi_bits) { struct dm_dev_internal *dd; struct list_head *devices = dm_table_get_devices(t); struct dm_target_callbacks *cb; int r = 0; list_for_each_entry(dd, devices, list) { struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev); char b[BDEVNAME_SIZE]; if (likely(q)) r |= bdi_congested(q->backing_dev_info, bdi_bits); else DMWARN_LIMIT("%s: any_congested: nonexistent device %s", dm_device_name(t->md), bdevname(dd->dm_dev->bdev, b)); } list_for_each_entry(cb, &t->target_callbacks, list) if (cb->congested_fn) r |= cb->congested_fn(cb, bdi_bits); return r; } struct mapped_device *dm_table_get_md(struct dm_table *t) { return t->md; } EXPORT_SYMBOL(dm_table_get_md); void dm_table_run_md_queue_async(struct dm_table *t) { struct mapped_device *md; struct request_queue *queue; if (!dm_table_request_based(t)) return; md = dm_table_get_md(t); queue = dm_get_md_queue(md); if (queue) blk_mq_run_hw_queues(queue, true); } EXPORT_SYMBOL(dm_table_run_md_queue_async);