/* * 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.h" #include <linux/module.h> #include <linux/vmalloc.h> #include <linux/blkdev.h> #include <linux/namei.h> #include <linux/ctype.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/interrupt.h> #include <linux/mutex.h> #include <linux/delay.h> #include <asm/atomic.h> #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) /* * The table has always exactly one reference from either mapped_device->map * or hash_cell->new_map. This reference is not counted in table->holders. * A pair of dm_create_table/dm_destroy_table functions is used for table * creation/destruction. * * Temporary references from the other code increase table->holders. A pair * of dm_table_get/dm_table_put functions is used to manipulate it. * * When the table is about to be destroyed, we wait for table->holders to * drop to zero. */ struct dm_table { struct mapped_device *md; atomic_t holders; unsigned 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; unsigned discards_supported:1; unsigned integrity_supported: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 = vmalloc(size); if (addr) memset(addr, 0, size); return addr; } /* * 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; int n = t->num_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); if (n) { memcpy(n_highs, t->highs, sizeof(*n_highs) * n); memcpy(n_targets, t->targets, sizeof(*n_targets) * n); } memset(n_highs + n, -1, sizeof(*n_highs) * (num - n)); 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); atomic_set(&t->holders, 0); t->discards_supported = 1; if (!num_targets) num_targets = KEYS_PER_NODE; num_targets = dm_round_up(num_targets, KEYS_PER_NODE); if (alloc_targets(t, num_targets)) { kfree(t); t = NULL; return -ENOMEM; } t->mode = mode; t->md = md; *result = t; return 0; } static void free_devices(struct list_head *devices) { 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("dm_table_destroy: dm_put_device call missing for %s", dd->dm_dev.name); kfree(dd); } } void dm_table_destroy(struct dm_table *t) { unsigned int i; if (!t) return; while (atomic_read(&t->holders)) msleep(1); smp_mb(); /* 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 */ if (t->devices.next != &t->devices) free_devices(&t->devices); dm_free_md_mempools(t->mempools); kfree(t); } void dm_table_get(struct dm_table *t) { atomic_inc(&t->holders); } void dm_table_put(struct dm_table *t) { if (!t) return; smp_mb__before_atomic_dec(); atomic_dec(&t->holders); } /* * Checks to see if we need to extend highs or targets. */ static inline int check_space(struct dm_table *t) { if (t->num_targets >= t->num_allocated) return alloc_targets(t, t->num_allocated * 2); return 0; } /* * 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; } /* * Open a device so we can use it as a map destination. */ static int open_dev(struct dm_dev_internal *d, dev_t dev, struct mapped_device *md) { static char *_claim_ptr = "I belong to device-mapper"; struct block_device *bdev; int r; BUG_ON(d->dm_dev.bdev); bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr); if (IS_ERR(bdev)) return PTR_ERR(bdev); r = bd_link_disk_holder(bdev, dm_disk(md)); if (r) { blkdev_put(bdev, d->dm_dev.mode | FMODE_EXCL); return r; } d->dm_dev.bdev = bdev; return 0; } /* * Close a device that we've been using. */ static void close_dev(struct dm_dev_internal *d, struct mapped_device *md) { if (!d->dm_dev.bdev) return; bd_unlink_disk_holder(d->dm_dev.bdev, dm_disk(md)); blkdev_put(d->dm_dev.bdev, d->dm_dev.mode | FMODE_EXCL); d->dm_dev.bdev = 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 (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_internal dd_new, dd_old; dd_new = dd_old = *dd; dd_new.dm_dev.mode |= new_mode; dd_new.dm_dev.bdev = NULL; r = open_dev(&dd_new, dd->dm_dev.bdev->bd_dev, md); if (r) return r; dd->dm_dev.mode |= new_mode; close_dev(&dd_old, md); return 0; } /* * Add a device to the list, or just increment the usage count if * it's already present. */ static int __table_get_device(struct dm_table *t, struct dm_target *ti, const char *path, fmode_t mode, struct dm_dev **result) { int r; dev_t uninitialized_var(dev); struct dm_dev_internal *dd; unsigned int major, minor; BUG_ON(!t); if (sscanf(path, "%u:%u", &major, &minor) == 2) { /* Extract the major/minor numbers */ dev = MKDEV(major, minor); if (MAJOR(dev) != major || MINOR(dev) != minor) return -EOVERFLOW; } else { /* convert the path to a device */ struct block_device *bdev = lookup_bdev(path); if (IS_ERR(bdev)) return PTR_ERR(bdev); dev = bdev->bd_dev; bdput(bdev); } dd = find_device(&t->devices, dev); if (!dd) { dd = kmalloc(sizeof(*dd), GFP_KERNEL); if (!dd) return -ENOMEM; dd->dm_dev.mode = mode; dd->dm_dev.bdev = NULL; if ((r = open_dev(dd, dev, t->md))) { kfree(dd); return r; } format_dev_t(dd->dm_dev.name, dev); atomic_set(&dd->count, 0); list_add(&dd->list, &t->devices); } else if (dd->dm_dev.mode != (mode | dd->dm_dev.mode)) { r = upgrade_mode(dd, mode, t->md); if (r) return r; } atomic_inc(&dd->count); *result = &dd->dm_dev; return 0; } 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); /* * Check if merge fn is supported. * If not we'll force DM to use PAGE_SIZE or * smaller I/O, just to be safe. */ if (q->merge_bvec_fn && !ti->type->merge) blk_limits_max_hw_sectors(limits, (unsigned int) (PAGE_SIZE >> 9)); return 0; } EXPORT_SYMBOL_GPL(dm_set_device_limits); int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, struct dm_dev **result) { return __table_get_device(ti->table, ti, path, mode, result); } /* * Decrement a devices use count and remove it if necessary. */ void dm_put_device(struct dm_target *ti, struct dm_dev *d) { struct dm_dev_internal *dd = container_of(d, struct dm_dev_internal, dm_dev); if (atomic_dec_and_test(&dd->count)) { close_dev(dd, ti->table->md); list_del(&dd->list); kfree(dd); } } /* * 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. */ static char **realloc_argv(unsigned *array_size, char **old_argv) { char **argv; unsigned new_size; new_size = *array_size ? *array_size * 2 : 64; argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL); if (argv) { memcpy(argv, old_argv, *array_size * sizeof(*argv)); *array_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 = 0; /* * Check each entry in the table in turn. */ while (i < dm_table_get_num_targets(table)) { ti = dm_table_get_target(table, i++); blk_set_default_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 ((r = check_space(t))) return r; 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; } 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"; r = -EINVAL; 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_requests) t->discards_supported = 0; return 0; bad: DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error); dm_put_target_type(tgt->type); return r; } static int dm_table_set_type(struct dm_table *t) { unsigned i; unsigned bio_based = 0, request_based = 0; struct dm_target *tgt; struct dm_dev_internal *dd; struct list_head *devices; for (i = 0; i < t->num_targets; i++) { tgt = t->targets + i; if (dm_target_request_based(tgt)) request_based = 1; else bio_based = 1; if (bio_based && request_based) { DMWARN("Inconsistent table: different target types" " can't be mixed up"); return -EINVAL; } } if (bio_based) { /* We must use this table as bio-based */ t->type = DM_TYPE_BIO_BASED; return 0; } BUG_ON(!request_based); /* No targets in this table */ /* Non-request-stackable devices can't be used for request-based dm */ devices = dm_table_get_devices(t); list_for_each_entry(dd, devices, list) { if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev.bdev))) { DMWARN("table load rejected: including" " non-request-stackable devices"); return -EINVAL; } } /* * 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) { DMWARN("Request-based dm doesn't support multiple targets yet"); return -EINVAL; } t->type = DM_TYPE_REQUEST_BASED; return 0; } unsigned dm_table_get_type(struct dm_table *t) { return t->type; } bool dm_table_request_based(struct dm_table *t) { return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED; } int dm_table_alloc_md_mempools(struct dm_table *t) { unsigned type = dm_table_get_type(t); if (unlikely(type == DM_TYPE_NONE)) { DMWARN("no table type is set, can't allocate mempools"); return -EINVAL; } t->mempools = dm_alloc_md_mempools(type, t->integrity_supported); 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; } /* * Get a disk whose integrity profile reflects the table's profile. * If %match_all is true, all devices' profiles must match. * If %match_all is false, all devices must at least have an * allocated integrity profile; but uninitialized is ok. * Returns NULL if integrity support was inconsistent or unavailable. */ static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t, bool match_all) { struct list_head *devices = dm_table_get_devices(t); struct dm_dev_internal *dd = NULL; struct gendisk *prev_disk = NULL, *template_disk = NULL; list_for_each_entry(dd, devices, list) { template_disk = dd->dm_dev.bdev->bd_disk; if (!blk_get_integrity(template_disk)) goto no_integrity; if (!match_all && !blk_integrity_is_initialized(template_disk)) continue; /* skip uninitialized profiles */ 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). * Stacked DM devices force a 2 stage integrity profile validation: * 1 - during load, validate all initialized integrity profiles match * 2 - during resume, validate all integrity profiles match */ static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md) { struct gendisk *template_disk = NULL; template_disk = dm_table_get_integrity_disk(t, false); if (!template_disk) return 0; if (!blk_integrity_is_initialized(dm_disk(md))) { t->integrity_supported = 1; return blk_integrity_register(dm_disk(md), NULL); } /* * If DM device already has an initalized integrity * profile the new profile should not conflict. */ if (blk_integrity_is_initialized(template_disk) && 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 initialized integrity profile */ t->integrity_supported = 1; 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_set_type(t); if (r) { DMERR("unable to set table type"); return r; } r = dm_table_build_index(t); if (r) { DMERR("unable to build btrees"); return r; } r = dm_table_prealloc_integrity(t, t->md); if (r) { DMERR("could not register integrity profile."); return r; } r = dm_table_alloc_md_mempools(t); 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); } sector_t dm_table_get_size(struct dm_table *t) { return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0; } 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]; } /* * 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 *uninitialized_var(ti); struct queue_limits ti_limits; unsigned i = 0; blk_set_default_limits(limits); while (i < dm_table_get_num_targets(table)) { blk_set_default_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); /* 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); } return validate_hardware_logical_block_alignment(table, limits); } /* * Set the integrity profile for this device if all devices used have * matching profiles. We're quite deep in the resume path but still * don't know if all devices (particularly DM devices this device * may be stacked on) have matching profiles. Even if the profiles * don't match we have no way to fail (to resume) at this point. */ static void dm_table_set_integrity(struct dm_table *t) { struct gendisk *template_disk = NULL; if (!blk_get_integrity(dm_disk(t->md))) return; template_disk = dm_table_get_integrity_disk(t, true); if (!template_disk && blk_integrity_is_initialized(dm_disk(t->md))) { DMWARN("%s: device no longer has a valid integrity profile", dm_device_name(t->md)); return; } blk_integrity_register(dm_disk(t->md), blk_get_integrity(template_disk)); } void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *limits) { /* * Copy table's limits to the DM device's request_queue */ q->limits = *limits; if (!dm_table_supports_discards(t)) queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q); else queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); dm_table_set_integrity(t); /* * QUEUE_FLAG_STACKABLE must be set after all queue settings are * visible to other CPUs because, once the flag is set, incoming bios * are processed by request-based dm, which refers to the queue * settings. * Until the flag set, bios are passed to bio-based dm and queued to * md->deferred where queue settings are not needed yet. * Those bios are passed to request-based dm at the resume time. */ smp_mb(); if (dm_table_request_based(t)) queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, 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; } static void suspend_targets(struct dm_table *t, unsigned postsuspend) { int i = t->num_targets; struct dm_target *ti = t->targets; while (i--) { if (postsuspend) { if (ti->type->postsuspend) ti->type->postsuspend(ti); } else if (ti->type->presuspend) ti->type->presuspend(ti); ti++; } } void dm_table_presuspend_targets(struct dm_table *t) { if (!t) return; suspend_targets(t, 0); } void dm_table_postsuspend_targets(struct dm_table *t) { if (!t) return; suspend_targets(t, 1); } int dm_table_resume_targets(struct dm_table *t) { int i, r = 0; 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) 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; } int dm_table_any_busy_target(struct dm_table *t) { unsigned i; struct dm_target *ti; for (i = 0; i < t->num_targets; i++) { ti = t->targets + i; if (ti->type->busy && ti->type->busy(ti)) return 1; } return 0; } struct mapped_device *dm_table_get_md(struct dm_table *t) { return t->md; } static int device_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); } bool dm_table_supports_discards(struct dm_table *t) { struct dm_target *ti; unsigned i = 0; if (!t->discards_supported) return 0; /* * Unless any target used by the table set discards_supported, * require at least one underlying device to support discards. * t->devices includes internal dm devices such as mirror logs * so we need to use iterate_devices here, which targets * supporting discard must provide. */ while (i < dm_table_get_num_targets(t)) { ti = dm_table_get_target(t, i++); if (ti->discards_supported) return 1; if (ti->type->iterate_devices && ti->type->iterate_devices(ti, device_discard_capable, NULL)) return 1; } return 0; } EXPORT_SYMBOL(dm_vcalloc); EXPORT_SYMBOL(dm_get_device); EXPORT_SYMBOL(dm_put_device); EXPORT_SYMBOL(dm_table_event); EXPORT_SYMBOL(dm_table_get_size); EXPORT_SYMBOL(dm_table_get_mode); EXPORT_SYMBOL(dm_table_get_md); EXPORT_SYMBOL(dm_table_put); EXPORT_SYMBOL(dm_table_get);