OSCL-LXR linux-6.0.1/​drivers/​md/​dm-table.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * 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 "dm-rq.h"
 
 #include <linux/module.h>
 #include <linux/vmalloc.h>
 #include <linux/blkdev.h>
 #include <linux/blk-integrity.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 <linux/atomic.h>
 #include <linux/blk-mq.h>
 #include <linux/mount.h>
 #include <linux/dax.h>
 
 #define DM_MSG_PREFIX "table"
 
 #define NODE_SIZE L1_CACHE_BYTES
 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
 
 /*
  * 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;
 }
 
 /*
  * 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.
      */
     n_highs = kvcalloc(num, sizeof(struct dm_target) + sizeof(sector_t),
                GFP_KERNEL);
     if (!n_highs)
         return -ENOMEM;
 
     n_targets = (struct dm_target *) (n_highs + num);
 
     memset(n_highs, -1, sizeof(*n_highs) * num);
     kvfree(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);
 
     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);
     }
 }
 
 static void dm_table_destroy_crypto_profile(struct dm_table *t);
 
 void dm_table_destroy(struct dm_table *t)
 {
     if (!t)
         return;
 
     /* free the indexes */
     if (t->depth >= 2)
         kvfree(t->index[t->depth - 2]);
 
     /* free the targets */
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (ti->type->dtr)
             ti->type->dtr(ti);
 
         dm_put_target_type(ti->type);
     }
 
     kvfree(t->highs);
 
     /* free the device list */
     free_devices(&t->devices, t->md);
 
     dm_free_md_mempools(t->mempools);
 
     dm_table_destroy_crypto_profile(t);
 
     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 queue_limits *limits = data;
     struct block_device *bdev = dev->bdev;
     sector_t dev_size = bdev_nr_sectors(bdev);
     unsigned short logical_block_size_sectors =
         limits->logical_block_size >> SECTOR_SHIFT;
 
     if (!dev_size)
         return 0;
 
     if ((start >= dev_size) || (start + len > dev_size)) {
         DMWARN("%s: %pg too small for target: "
                "start=%llu, len=%llu, dev_size=%llu",
                dm_device_name(ti->table->md), bdev,
                (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_is_zoned(bdev)) {
         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 %pg",
                    dm_device_name(ti->table->md),
                    (unsigned long long)start,
                    zone_sectors, bdev);
             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 %pg",
                    dm_device_name(ti->table->md),
                    (unsigned long long)len,
                    zone_sectors, bdev);
             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 %pg",
                dm_device_name(ti->table->md),
                (unsigned long long)start,
                limits->logical_block_size, bdev);
         return 1;
     }
 
     if (len & (logical_block_size_sectors - 1)) {
         DMWARN("%s: len=%llu not aligned to h/w "
                "logical block size %u of %pg",
                dm_device_name(ti->table->md),
                (unsigned long long)len,
                limits->logical_block_size, bdev);
         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.
  */
 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;
 
     if (lookup_bdev(path, &dev))
         dev = name_to_dev_t(path);
     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;
     unsigned int major, minor;
     char dummy;
     struct dm_dev_internal *dd;
     struct dm_table *t = ti->table;
 
     BUG_ON(!t);
 
     if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
         /* Extract the major/minor numbers */
         dev = MKDEV(major, minor);
         if (MAJOR(dev) != major || MINOR(dev) != minor)
             return -EOVERFLOW;
     } else {
         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);
 
     if (unlikely(!q)) {
         DMWARN("%s: Cannot set limits for nonexistent device %pg",
                dm_device_name(ti->table->md), bdev);
         return 0;
     }
 
     if (blk_stack_limits(limits, &q->limits,
             get_start_sect(bdev) + start) < 0)
         DMWARN("%s: adding target device %pg caused an alignment inconsistency: "
                "physical_block_size=%u, logical_block_size=%u, "
                "alignment_offset=%u, start=%llu",
                dm_device_name(ti->table->md), bdev,
                q->limits.physical_block_size,
                q->limits.logical_block_size,
                q->limits.alignment_offset,
                (unsigned long long) start << SECTOR_SHIFT);
     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 *t, struct dm_target *ti)
 {
     struct dm_target *prev;
 
     if (!t->num_targets)
         return !ti->begin;
 
     prev = &t->targets[t->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 && old_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 *t,
                              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 *ti;
     struct queue_limits ti_limits;
     unsigned int i;
 
     /*
      * Check each entry in the table in turn.
      */
     for (i = 0; i < t->num_targets; i++) {
         ti = dm_table_get_target(t, 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(t->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 *ti;
 
     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);
 
     ti = t->targets + t->num_targets;
     memset(ti, 0, sizeof(*ti));
 
     if (!len) {
         DMERR("%s: zero-length target", dm_device_name(t->md));
         return -EINVAL;
     }
 
     ti->type = dm_get_target_type(type);
     if (!ti->type) {
         DMERR("%s: %s: unknown target type", dm_device_name(t->md), type);
         return -EINVAL;
     }
 
     if (dm_target_needs_singleton(ti->type)) {
         if (t->num_targets) {
             ti->error = "singleton target type must appear alone in table";
             goto bad;
         }
         t->singleton = true;
     }
 
     if (dm_target_always_writeable(ti->type) && !(t->mode & FMODE_WRITE)) {
         ti->error = "target type may not be included in a read-only table";
         goto bad;
     }
 
     if (t->immutable_target_type) {
         if (t->immutable_target_type != ti->type) {
             ti->error = "immutable target type cannot be mixed with other target types";
             goto bad;
         }
     } else if (dm_target_is_immutable(ti->type)) {
         if (t->num_targets) {
             ti->error = "immutable target type cannot be mixed with other target types";
             goto bad;
         }
         t->immutable_target_type = ti->type;
     }
 
     if (dm_target_has_integrity(ti->type))
         t->integrity_added = 1;
 
     ti->table = t;
     ti->begin = start;
     ti->len = len;
     ti->error = "Unknown error";
 
     /*
      * Does this target adjoin the previous one ?
      */
     if (!adjoin(t, ti)) {
         ti->error = "Gap in table";
         goto bad;
     }
 
     r = dm_split_args(&argc, &argv, params);
     if (r) {
         ti->error = "couldn't split parameters";
         goto bad;
     }
 
     r = ti->type->ctr(ti, argc, argv);
     kfree(argv);
     if (r)
         goto bad;
 
     t->highs[t->num_targets++] = ti->begin + ti->len - 1;
 
     if (!ti->num_discard_bios && ti->discards_supported)
         DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
                dm_device_name(t->md), type);
 
     if (ti->limit_swap_bios && !static_key_enabled(&swap_bios_enabled.key))
         static_branch_enable(&swap_bios_enabled);
 
     return 0;
 
  bad:
     DMERR("%s: %s: %s (%pe)", dm_device_name(t->md), type, ti->error, ERR_PTR(r));
     dm_put_target_type(ti->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);
 }
 
 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);
 
 /* validate the dax capability of the target device span */
 static int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
             sector_t start, sector_t len, void *data)
 {
     if (dev->dax_dev)
         return false;
 
     DMDEBUG("%pg: error: dax unsupported by block device", dev->bdev);
     return true;
 }
 
 /* Check devices support synchronous DAX */
 static int device_not_dax_synchronous_capable(struct dm_target *ti, struct dm_dev *dev,
                           sector_t start, sector_t len, void *data)
 {
     return !dev->dax_dev || !dax_synchronous(dev->dax_dev);
 }
 
 static bool dm_table_supports_dax(struct dm_table *t,
                   iterate_devices_callout_fn iterate_fn)
 {
     /* Ensure that all targets support DAX. */
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (!ti->type->direct_access)
             return false;
 
         if (!ti->type->iterate_devices ||
             ti->type->iterate_devices(ti, iterate_fn, NULL))
             return false;
     }
 
     return true;
 }
 
 static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
                   sector_t start, sector_t len, void *data)
 {
     struct block_device *bdev = dev->bdev;
     struct request_queue *q = bdev_get_queue(bdev);
 
     /* request-based cannot stack on partitions! */
     if (bdev_is_partition(bdev))
         return false;
 
     return queue_is_mq(q);
 }
 
 static int dm_table_determine_type(struct dm_table *t)
 {
     unsigned bio_based = 0, request_based = 0, hybrid = 0;
     struct dm_target *ti;
     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);
         goto verify_rq_based;
     }
 
     for (unsigned int i = 0; i < t->num_targets; i++) {
         ti = dm_table_get_target(t, i);
         if (dm_target_hybrid(ti))
             hybrid = 1;
         else if (dm_target_request_based(ti))
             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, device_not_dax_capable) ||
             (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED)) {
             t->type = DM_TYPE_DAX_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("request-based DM doesn't support multiple targets");
         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;
     }
 
     ti = dm_table_get_immutable_target(t);
     if (!ti) {
         DMERR("table load rejected: immutable target is required");
         return -EINVAL;
     } else if (ti->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 (!ti->type->iterate_devices ||
         !ti->type->iterate_devices(ti, device_is_rq_stackable, NULL)) {
         DMERR("table load rejected: including non-request-stackable devices");
         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)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *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 bool dm_table_supports_poll(struct dm_table *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 int per_io_data_size = 0, front_pad, io_front_pad;
     unsigned int min_pool_size = 0, pool_size;
     struct dm_md_mempools *pools;
 
     if (unlikely(type == DM_TYPE_NONE)) {
         DMWARN("no table type is set, can't allocate mempools");
         return -EINVAL;
     }
 
     pools = kzalloc_node(sizeof(*pools), GFP_KERNEL, md->numa_node_id);
     if (!pools)
         return -ENOMEM;
 
     if (type == DM_TYPE_REQUEST_BASED) {
         pool_size = dm_get_reserved_rq_based_ios();
         front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
         goto init_bs;
     }
 
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, 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);
     }
     pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
     front_pad = roundup(per_io_data_size,
         __alignof__(struct dm_target_io)) + DM_TARGET_IO_BIO_OFFSET;
 
     io_front_pad = roundup(per_io_data_size,
         __alignof__(struct dm_io)) + DM_IO_BIO_OFFSET;
     if (bioset_init(&pools->io_bs, pool_size, io_front_pad,
             dm_table_supports_poll(t) ? BIOSET_PERCPU_CACHE : 0))
         goto out_free_pools;
     if (t->integrity_supported &&
         bioset_integrity_create(&pools->io_bs, pool_size))
         goto out_free_pools;
 init_bs:
     if (bioset_init(&pools->bs, pool_size, front_pad, 0))
         goto out_free_pools;
     if (t->integrity_supported &&
         bioset_integrity_create(&pools->bs, pool_size))
         goto out_free_pools;
 
     t->mempools = pools;
     return 0;
 
 out_free_pools:
     dm_free_md_mempools(pools);
     return -ENOMEM;
 }
 
 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 = kvcalloc(total, NODE_SIZE, GFP_KERNEL);
     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;
 
     for (unsigned int i = 0; i < t->num_targets; 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;
 }
 
 #ifdef CONFIG_BLK_INLINE_ENCRYPTION
 
 struct dm_crypto_profile {
     struct blk_crypto_profile profile;
     struct mapped_device *md;
 };
 
 struct dm_keyslot_evict_args {
     const struct blk_crypto_key *key;
     int err;
 };
 
 static int dm_keyslot_evict_callback(struct dm_target *ti, struct dm_dev *dev,
                      sector_t start, sector_t len, void *data)
 {
     struct dm_keyslot_evict_args *args = data;
     int err;
 
     err = blk_crypto_evict_key(bdev_get_queue(dev->bdev), args->key);
     if (!args->err)
         args->err = err;
     /* Always try to evict the key from all devices. */
     return 0;
 }
 
 /*
  * When an inline encryption key is evicted from a device-mapper device, evict
  * it from all the underlying devices.
  */
 static int dm_keyslot_evict(struct blk_crypto_profile *profile,
                 const struct blk_crypto_key *key, unsigned int slot)
 {
     struct mapped_device *md =
         container_of(profile, struct dm_crypto_profile, profile)->md;
     struct dm_keyslot_evict_args args = { key };
     struct dm_table *t;
     int srcu_idx;
 
     t = dm_get_live_table(md, &srcu_idx);
     if (!t)
         return 0;
 
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (!ti->type->iterate_devices)
             continue;
         ti->type->iterate_devices(ti, dm_keyslot_evict_callback, &args);
     }
 
     dm_put_live_table(md, srcu_idx);
     return args.err;
 }
 
 static int
 device_intersect_crypto_capabilities(struct dm_target *ti, struct dm_dev *dev,
                      sector_t start, sector_t len, void *data)
 {
     struct blk_crypto_profile *parent = data;
     struct blk_crypto_profile *child =
         bdev_get_queue(dev->bdev)->crypto_profile;
 
     blk_crypto_intersect_capabilities(parent, child);
     return 0;
 }
 
 void dm_destroy_crypto_profile(struct blk_crypto_profile *profile)
 {
     struct dm_crypto_profile *dmcp = container_of(profile,
                               struct dm_crypto_profile,
                               profile);
 
     if (!profile)
         return;
 
     blk_crypto_profile_destroy(profile);
     kfree(dmcp);
 }
 
 static void dm_table_destroy_crypto_profile(struct dm_table *t)
 {
     dm_destroy_crypto_profile(t->crypto_profile);
     t->crypto_profile = NULL;
 }
 
 /*
  * Constructs and initializes t->crypto_profile with a crypto profile that
  * represents the common set of crypto capabilities of the devices described by
  * the dm_table.  However, if the constructed crypto profile doesn't support all
  * crypto capabilities that are supported by the current mapped_device, it
  * returns an error instead, since we don't support removing crypto capabilities
  * on table changes.  Finally, if the constructed crypto profile is "empty" (has
  * no crypto capabilities at all), it just sets t->crypto_profile to NULL.
  */
 static int dm_table_construct_crypto_profile(struct dm_table *t)
 {
     struct dm_crypto_profile *dmcp;
     struct blk_crypto_profile *profile;
     unsigned int i;
     bool empty_profile = true;
 
     dmcp = kmalloc(sizeof(*dmcp), GFP_KERNEL);
     if (!dmcp)
         return -ENOMEM;
     dmcp->md = t->md;
 
     profile = &dmcp->profile;
     blk_crypto_profile_init(profile, 0);
     profile->ll_ops.keyslot_evict = dm_keyslot_evict;
     profile->max_dun_bytes_supported = UINT_MAX;
     memset(profile->modes_supported, 0xFF,
            sizeof(profile->modes_supported));
 
     for (i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (!dm_target_passes_crypto(ti->type)) {
             blk_crypto_intersect_capabilities(profile, NULL);
             break;
         }
         if (!ti->type->iterate_devices)
             continue;
         ti->type->iterate_devices(ti,
                       device_intersect_crypto_capabilities,
                       profile);
     }
 
     if (t->md->queue &&
         !blk_crypto_has_capabilities(profile,
                      t->md->queue->crypto_profile)) {
         DMWARN("Inline encryption capabilities of new DM table were more restrictive than the old table's. This is not supported!");
         dm_destroy_crypto_profile(profile);
         return -EINVAL;
     }
 
     /*
      * If the new profile doesn't actually support any crypto capabilities,
      * we may as well represent it with a NULL profile.
      */
     for (i = 0; i < ARRAY_SIZE(profile->modes_supported); i++) {
         if (profile->modes_supported[i]) {
             empty_profile = false;
             break;
         }
     }
 
     if (empty_profile) {
         dm_destroy_crypto_profile(profile);
         profile = NULL;
     }
 
     /*
      * t->crypto_profile is only set temporarily while the table is being
      * set up, and it gets set to NULL after the profile has been
      * transferred to the request_queue.
      */
     t->crypto_profile = profile;
 
     return 0;
 }
 
 static void dm_update_crypto_profile(struct request_queue *q,
                      struct dm_table *t)
 {
     if (!t->crypto_profile)
         return;
 
     /* Make the crypto profile less restrictive. */
     if (!q->crypto_profile) {
         blk_crypto_register(t->crypto_profile, q);
     } else {
         blk_crypto_update_capabilities(q->crypto_profile,
                            t->crypto_profile);
         dm_destroy_crypto_profile(t->crypto_profile);
     }
     t->crypto_profile = NULL;
 }
 
 #else /* CONFIG_BLK_INLINE_ENCRYPTION */
 
 static int dm_table_construct_crypto_profile(struct dm_table *t)
 {
     return 0;
 }
 
 void dm_destroy_crypto_profile(struct blk_crypto_profile *profile)
 {
 }
 
 static void dm_table_destroy_crypto_profile(struct dm_table *t)
 {
 }
 
 static void dm_update_crypto_profile(struct request_queue *q,
                      struct dm_table *t)
 {
 }
 
 #endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
 
 /*
  * 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_construct_crypto_profile(t);
     if (r) {
         DMERR("could not construct crypto 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)
 {
     mutex_lock(&_event_lock);
     if (t->event_fn)
         t->event_fn(t->event_context);
     mutex_unlock(&_event_lock);
 }
 EXPORT_SYMBOL(dm_table_event);
 
 inline 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);
 
 /*
  * Search the btree for the correct target.
  *
  * Caller should check returned pointer for NULL
  * 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;
 
     if (unlikely(sector >= dm_table_get_size(t)))
         return NULL;
 
     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 device_not_poll_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 !test_bit(QUEUE_FLAG_POLL, &q->queue_flags);
 }
 
 /*
  * type->iterate_devices() should be called when the sanity check needs to
  * iterate and check all underlying data devices. iterate_devices() will
  * iterate all underlying data devices until it encounters a non-zero return
  * code, returned by whether the input iterate_devices_callout_fn, or
  * iterate_devices() itself internally.
  *
  * For some target type (e.g. dm-stripe), one call of iterate_devices() may
  * iterate multiple underlying devices internally, in which case a non-zero
  * return code returned by iterate_devices_callout_fn will stop the iteration
  * in advance.
  *
  * Cases requiring _any_ underlying device supporting some kind of attribute,
  * should use the iteration structure like dm_table_any_dev_attr(), or call
  * it directly. @func should handle semantics of positive examples, e.g.
  * capable of something.
  *
  * Cases requiring _all_ underlying devices supporting some kind of attribute,
  * should use the iteration structure like dm_table_supports_nowait() or
  * dm_table_supports_discards(). Or introduce dm_table_all_devs_attr() that
  * uses an @anti_func that handle semantics of counter examples, e.g. not
  * capable of something. So: return !dm_table_any_dev_attr(t, anti_func, data);
  */
 static bool dm_table_any_dev_attr(struct dm_table *t,
                   iterate_devices_callout_fn func, void *data)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (ti->type->iterate_devices &&
             ti->type->iterate_devices(ti, func, data))
             return true;
         }
 
     return false;
 }
 
 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;
 }
 
 static bool dm_table_supports_poll(struct dm_table *t)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (!ti->type->iterate_devices ||
             ti->type->iterate_devices(ti, device_not_poll_capable, NULL))
             return false;
     }
 
     return true;
 }
 
 /*
  * 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 *t)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
         unsigned num_devices = 0;
 
         if (!ti->type->iterate_devices)
             return false;
 
         ti->type->iterate_devices(ti, count_device, &num_devices);
         if (num_devices)
             return false;
     }
 
     return true;
 }
 
 static int device_not_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 blk_queue_zoned_model(q) != *zoned_model;
 }
 
 /*
  * Check the device zoned model based on the target feature flag. If the target
  * has the DM_TARGET_ZONED_HM feature flag set, host-managed zoned devices are
  * also accepted but all devices must have the same zoned model. If the target
  * has the DM_TARGET_MIXED_ZONED_MODEL feature set, the devices can have any
  * zoned model with all zoned devices having the same zone size.
  */
 static bool dm_table_supports_zoned_model(struct dm_table *t,
                       enum blk_zoned_model zoned_model)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (dm_target_supports_zoned_hm(ti->type)) {
             if (!ti->type->iterate_devices ||
                 ti->type->iterate_devices(ti, device_not_zoned_model,
                               &zoned_model))
                 return false;
         } else if (!dm_target_supports_mixed_zoned_model(ti->type)) {
             if (zoned_model == BLK_ZONED_HM)
                 return false;
         }
     }
 
     return true;
 }
 
 static int device_not_matches_zone_sectors(struct dm_target *ti, struct dm_dev *dev,
                        sector_t start, sector_t len, void *data)
 {
     unsigned int *zone_sectors = data;
 
     if (!bdev_is_zoned(dev->bdev))
         return 0;
     return bdev_zone_sectors(dev->bdev) != *zone_sectors;
 }
 
 /*
  * Check consistency of zoned model and zone sectors across all targets. For
  * zone sectors, if the destination device is a zoned block device, it shall
  * have the specified zone_sectors.
  */
 static int validate_hardware_zoned_model(struct dm_table *t,
                      enum blk_zoned_model zoned_model,
                      unsigned int zone_sectors)
 {
     if (zoned_model == BLK_ZONED_NONE)
         return 0;
 
     if (!dm_table_supports_zoned_model(t, zoned_model)) {
         DMERR("%s: zoned model is not consistent across all devices",
               dm_device_name(t->md));
         return -EINVAL;
     }
 
     /* Check zone size validity and compatibility */
     if (!zone_sectors || !is_power_of_2(zone_sectors))
         return -EINVAL;
 
     if (dm_table_any_dev_attr(t, device_not_matches_zone_sectors, &zone_sectors)) {
         DMERR("%s: zone sectors is not consistent across all zoned devices",
               dm_device_name(t->md));
         return -EINVAL;
     }
 
     return 0;
 }
 
 /*
  * Establish the new table's queue_limits and validate them.
  */
 int dm_calculate_queue_limits(struct dm_table *t,
                   struct queue_limits *limits)
 {
     struct queue_limits ti_limits;
     enum blk_zoned_model zoned_model = BLK_ZONED_NONE;
     unsigned int zone_sectors = 0;
 
     blk_set_stacking_limits(limits);
 
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         blk_set_stacking_limits(&ti_limits);
 
         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(t->md),
                    (unsigned long long) ti->begin,
                    (unsigned long long) ti->len);
     }
 
     /*
      * 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(t, zoned_model, zone_sectors))
         return -EINVAL;
 
     return validate_hardware_logical_block_alignment(t, 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->queue_flags & flush);
 }
 
 static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
 {
     /*
      * 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 (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *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 device_is_rotational(struct dm_target *ti, struct dm_dev *dev,
                 sector_t start, sector_t len, void *data)
 {
     return !bdev_nonrot(dev->bdev);
 }
 
 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 !blk_queue_add_random(q);
 }
 
 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->limits.max_write_zeroes_sectors;
 }
 
 static bool dm_table_supports_write_zeroes(struct dm_table *t)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *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_nowait_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 !blk_queue_nowait(q);
 }
 
 static bool dm_table_supports_nowait(struct dm_table *t)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, i);
 
         if (!dm_target_supports_nowait(ti->type))
             return false;
 
         if (!ti->type->iterate_devices ||
             ti->type->iterate_devices(ti, device_not_nowait_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)
 {
     return !bdev_max_discard_sectors(dev->bdev);
 }
 
 static bool dm_table_supports_discards(struct dm_table *t)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *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)
 {
     return !bdev_max_secure_erase_sectors(dev->bdev);
 }
 
 static bool dm_table_supports_secure_erase(struct dm_table *t)
 {
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *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;
 }
 
 static int device_requires_stable_pages(struct dm_target *ti,
                     struct dm_dev *dev, sector_t start,
                     sector_t len, void *data)
 {
     return bdev_stable_writes(dev->bdev);
 }
 
 int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
                   struct queue_limits *limits)
 {
     bool wc = false, fua = false;
     int r;
 
     /*
      * Copy table's limits to the DM device's request_queue
      */
     q->limits = *limits;
 
     if (dm_table_supports_nowait(t))
         blk_queue_flag_set(QUEUE_FLAG_NOWAIT, q);
     else
         blk_queue_flag_clear(QUEUE_FLAG_NOWAIT, q);
 
     if (!dm_table_supports_discards(t)) {
         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;
     }
 
     if (!dm_table_supports_secure_erase(t))
         q->limits.max_secure_erase_sectors = 0;
 
     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, device_not_dax_capable)) {
         blk_queue_flag_set(QUEUE_FLAG_DAX, q);
         if (dm_table_supports_dax(t, device_not_dax_synchronous_capable))
             set_dax_synchronous(t->md->dax_dev);
     }
     else
         blk_queue_flag_clear(QUEUE_FLAG_DAX, q);
 
     if (dm_table_any_dev_attr(t, device_dax_write_cache_enabled, NULL))
         dax_write_cache(t->md->dax_dev, true);
 
     /* Ensure that all underlying devices are non-rotational. */
     if (dm_table_any_dev_attr(t, device_is_rotational, NULL))
         blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
     else
         blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 
     if (!dm_table_supports_write_zeroes(t))
         q->limits.max_write_zeroes_sectors = 0;
 
     dm_table_verify_integrity(t);
 
     /*
      * Some devices don't use blk_integrity but still want stable pages
      * because they do their own checksumming.
      * If any underlying device requires stable pages, a table must require
      * them as well.  Only targets that support iterate_devices are considered:
      * don't want error, zero, etc to require stable pages.
      */
     if (dm_table_any_dev_attr(t, device_requires_stable_pages, NULL))
         blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
     else
         blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, q);
 
     /*
      * 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_any_dev_attr(t, device_is_not_random, NULL))
         blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q);
 
     /*
      * For a zoned target, setup the zones related queue attributes
      * and resources necessary for zone append emulation if necessary.
      */
     if (blk_queue_is_zoned(q)) {
         r = dm_set_zones_restrictions(t, q);
         if (r)
             return r;
         if (!static_key_enabled(&zoned_enabled.key))
             static_branch_enable(&zoned_enabled);
     }
 
     dm_update_crypto_profile(q, t);
     disk_update_readahead(t->md->disk);
 
     /*
      * Check for request-based device is left to
      * dm_mq_init_request_queue()->blk_mq_init_allocated_queue().
      *
      * For bio-based device, only set QUEUE_FLAG_POLL when all
      * underlying devices supporting polling.
      */
     if (__table_type_bio_based(t->type)) {
         if (dm_table_supports_poll(t))
             blk_queue_flag_set(QUEUE_FLAG_POLL, q);
         else
             blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
     }
 
     return 0;
 }
 
 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)
 {
     lockdep_assert_held(&t->md->suspend_lock);
 
     for (unsigned int i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, 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;
         }
     }
 }
 
 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)
 {
     unsigned int i;
     int r = 0;
 
     lockdep_assert_held(&t->md->suspend_lock);
 
     for (i = 0; i < t->num_targets; i++) {
         struct dm_target *ti = dm_table_get_target(t, 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 = dm_table_get_target(t, i);
 
         if (ti->type->resume)
             ti->type->resume(ti);
     }
 
     return 0;
 }
 
 struct mapped_device *dm_table_get_md(struct dm_table *t)
 {
     return t->md;
 }
 EXPORT_SYMBOL(dm_table_get_md);
 
 const char *dm_table_device_name(struct dm_table *t)
 {
     return dm_device_name(t->md);
 }
 EXPORT_SYMBOL_GPL(dm_table_device_name);
 
 void dm_table_run_md_queue_async(struct dm_table *t)
 {
     if (!dm_table_request_based(t))
         return;
 
     if (t->md->queue)
         blk_mq_run_hw_queues(t->md->queue, true);
 }
 EXPORT_SYMBOL(dm_table_run_md_queue_async);
 

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