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	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, 2002 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 "dm-uevent.h"
 #include "dm-ima.h"
 
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
 #include <linux/blkpg.h>
 #include <linux/bio.h>
 #include <linux/mempool.h>
 #include <linux/dax.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
 #include <linux/uio.h>
 #include <linux/hdreg.h>
 #include <linux/delay.h>
 #include <linux/wait.h>
 #include <linux/pr.h>
 #include <linux/refcount.h>
 #include <linux/part_stat.h>
 #include <linux/blk-crypto.h>
 #include <linux/blk-crypto-profile.h>
 
 #define DM_MSG_PREFIX "core"
 
 /*
  * Cookies are numeric values sent with CHANGE and REMOVE
  * uevents while resuming, removing or renaming the device.
  */
 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
 #define DM_COOKIE_LENGTH 24
 
 /*
  * For REQ_POLLED fs bio, this flag is set if we link mapped underlying
  * dm_io into one list, and reuse bio->bi_private as the list head. Before
  * ending this fs bio, we will recover its ->bi_private.
  */
 #define REQ_DM_POLL_LIST    REQ_DRV
 
 static const char *_name = DM_NAME;
 
 static unsigned int major = 0;
 static unsigned int _major = 0;
 
 static DEFINE_IDR(_minor_idr);
 
 static DEFINE_SPINLOCK(_minor_lock);
 
 static void do_deferred_remove(struct work_struct *w);
 
 static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
 
 static struct workqueue_struct *deferred_remove_workqueue;
 
 atomic_t dm_global_event_nr = ATOMIC_INIT(0);
 DECLARE_WAIT_QUEUE_HEAD(dm_global_eventq);
 
 void dm_issue_global_event(void)
 {
     atomic_inc(&dm_global_event_nr);
     wake_up(&dm_global_eventq);
 }
 
 DEFINE_STATIC_KEY_FALSE(stats_enabled);
 DEFINE_STATIC_KEY_FALSE(swap_bios_enabled);
 DEFINE_STATIC_KEY_FALSE(zoned_enabled);
 
 /*
  * One of these is allocated (on-stack) per original bio.
  */
 struct clone_info {
     struct dm_table *map;
     struct bio *bio;
     struct dm_io *io;
     sector_t sector;
     unsigned sector_count;
     bool is_abnormal_io:1;
     bool submit_as_polled:1;
 };
 
 static inline struct dm_target_io *clone_to_tio(struct bio *clone)
 {
     return container_of(clone, struct dm_target_io, clone);
 }
 
 void *dm_per_bio_data(struct bio *bio, size_t data_size)
 {
     if (!dm_tio_flagged(clone_to_tio(bio), DM_TIO_INSIDE_DM_IO))
         return (char *)bio - DM_TARGET_IO_BIO_OFFSET - data_size;
     return (char *)bio - DM_IO_BIO_OFFSET - data_size;
 }
 EXPORT_SYMBOL_GPL(dm_per_bio_data);
 
 struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
 {
     struct dm_io *io = (struct dm_io *)((char *)data + data_size);
     if (io->magic == DM_IO_MAGIC)
         return (struct bio *)((char *)io + DM_IO_BIO_OFFSET);
     BUG_ON(io->magic != DM_TIO_MAGIC);
     return (struct bio *)((char *)io + DM_TARGET_IO_BIO_OFFSET);
 }
 EXPORT_SYMBOL_GPL(dm_bio_from_per_bio_data);
 
 unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
 {
     return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
 }
 EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr);
 
 #define MINOR_ALLOCED ((void *)-1)
 
 #define DM_NUMA_NODE NUMA_NO_NODE
 static int dm_numa_node = DM_NUMA_NODE;
 
 #define DEFAULT_SWAP_BIOS   (8 * 1048576 / PAGE_SIZE)
 static int swap_bios = DEFAULT_SWAP_BIOS;
 static int get_swap_bios(void)
 {
     int latch = READ_ONCE(swap_bios);
     if (unlikely(latch <= 0))
         latch = DEFAULT_SWAP_BIOS;
     return latch;
 }
 
 struct table_device {
     struct list_head list;
     refcount_t count;
     struct dm_dev dm_dev;
 };
 
 /*
  * Bio-based DM's mempools' reserved IOs set by the user.
  */
 #define RESERVED_BIO_BASED_IOS      16
 static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
 
 static int __dm_get_module_param_int(int *module_param, int min, int max)
 {
     int param = READ_ONCE(*module_param);
     int modified_param = 0;
     bool modified = true;
 
     if (param < min)
         modified_param = min;
     else if (param > max)
         modified_param = max;
     else
         modified = false;
 
     if (modified) {
         (void)cmpxchg(module_param, param, modified_param);
         param = modified_param;
     }
 
     return param;
 }
 
 unsigned __dm_get_module_param(unsigned *module_param,
                    unsigned def, unsigned max)
 {
     unsigned param = READ_ONCE(*module_param);
     unsigned modified_param = 0;
 
     if (!param)
         modified_param = def;
     else if (param > max)
         modified_param = max;
 
     if (modified_param) {
         (void)cmpxchg(module_param, param, modified_param);
         param = modified_param;
     }
 
     return param;
 }
 
 unsigned dm_get_reserved_bio_based_ios(void)
 {
     return __dm_get_module_param(&reserved_bio_based_ios,
                      RESERVED_BIO_BASED_IOS, DM_RESERVED_MAX_IOS);
 }
 EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
 
 static unsigned dm_get_numa_node(void)
 {
     return __dm_get_module_param_int(&dm_numa_node,
                      DM_NUMA_NODE, num_online_nodes() - 1);
 }
 
 static int __init local_init(void)
 {
     int r;
 
     r = dm_uevent_init();
     if (r)
         return r;
 
     deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
     if (!deferred_remove_workqueue) {
         r = -ENOMEM;
         goto out_uevent_exit;
     }
 
     _major = major;
     r = register_blkdev(_major, _name);
     if (r < 0)
         goto out_free_workqueue;
 
     if (!_major)
         _major = r;
 
     return 0;
 
 out_free_workqueue:
     destroy_workqueue(deferred_remove_workqueue);
 out_uevent_exit:
     dm_uevent_exit();
 
     return r;
 }
 
 static void local_exit(void)
 {
     flush_scheduled_work();
     destroy_workqueue(deferred_remove_workqueue);
 
     unregister_blkdev(_major, _name);
     dm_uevent_exit();
 
     _major = 0;
 
     DMINFO("cleaned up");
 }
 
 static int (*_inits[])(void) __initdata = {
     local_init,
     dm_target_init,
     dm_linear_init,
     dm_stripe_init,
     dm_io_init,
     dm_kcopyd_init,
     dm_interface_init,
     dm_statistics_init,
 };
 
 static void (*_exits[])(void) = {
     local_exit,
     dm_target_exit,
     dm_linear_exit,
     dm_stripe_exit,
     dm_io_exit,
     dm_kcopyd_exit,
     dm_interface_exit,
     dm_statistics_exit,
 };
 
 static int __init dm_init(void)
 {
     const int count = ARRAY_SIZE(_inits);
     int r, i;
 
 #if (IS_ENABLED(CONFIG_IMA) && !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE))
     DMWARN("CONFIG_IMA_DISABLE_HTABLE is disabled."
            " Duplicate IMA measurements will not be recorded in the IMA log.");
 #endif
 
     for (i = 0; i < count; i++) {
         r = _inits[i]();
         if (r)
             goto bad;
     }
 
     return 0;
 bad:
     while (i--)
         _exits[i]();
 
     return r;
 }
 
 static void __exit dm_exit(void)
 {
     int i = ARRAY_SIZE(_exits);
 
     while (i--)
         _exits[i]();
 
     /*
      * Should be empty by this point.
      */
     idr_destroy(&_minor_idr);
 }
 
 /*
  * Block device functions
  */
 int dm_deleting_md(struct mapped_device *md)
 {
     return test_bit(DMF_DELETING, &md->flags);
 }
 
 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 {
     struct mapped_device *md;
 
     spin_lock(&_minor_lock);
 
     md = bdev->bd_disk->private_data;
     if (!md)
         goto out;
 
     if (test_bit(DMF_FREEING, &md->flags) ||
         dm_deleting_md(md)) {
         md = NULL;
         goto out;
     }
 
     dm_get(md);
     atomic_inc(&md->open_count);
 out:
     spin_unlock(&_minor_lock);
 
     return md ? 0 : -ENXIO;
 }
 
 static void dm_blk_close(struct gendisk *disk, fmode_t mode)
 {
     struct mapped_device *md;
 
     spin_lock(&_minor_lock);
 
     md = disk->private_data;
     if (WARN_ON(!md))
         goto out;
 
     if (atomic_dec_and_test(&md->open_count) &&
         (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
         queue_work(deferred_remove_workqueue, &deferred_remove_work);
 
     dm_put(md);
 out:
     spin_unlock(&_minor_lock);
 }
 
 int dm_open_count(struct mapped_device *md)
 {
     return atomic_read(&md->open_count);
 }
 
 /*
  * Guarantees nothing is using the device before it's deleted.
  */
 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
 {
     int r = 0;
 
     spin_lock(&_minor_lock);
 
     if (dm_open_count(md)) {
         r = -EBUSY;
         if (mark_deferred)
             set_bit(DMF_DEFERRED_REMOVE, &md->flags);
     } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
         r = -EEXIST;
     else
         set_bit(DMF_DELETING, &md->flags);
 
     spin_unlock(&_minor_lock);
 
     return r;
 }
 
 int dm_cancel_deferred_remove(struct mapped_device *md)
 {
     int r = 0;
 
     spin_lock(&_minor_lock);
 
     if (test_bit(DMF_DELETING, &md->flags))
         r = -EBUSY;
     else
         clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
 
     spin_unlock(&_minor_lock);
 
     return r;
 }
 
 static void do_deferred_remove(struct work_struct *w)
 {
     dm_deferred_remove();
 }
 
 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
     struct mapped_device *md = bdev->bd_disk->private_data;
 
     return dm_get_geometry(md, geo);
 }
 
 static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
                 struct block_device **bdev)
 {
     struct dm_target *ti;
     struct dm_table *map;
     int r;
 
 retry:
     r = -ENOTTY;
     map = dm_get_live_table(md, srcu_idx);
     if (!map || !dm_table_get_size(map))
         return r;
 
     /* We only support devices that have a single target */
     if (map->num_targets != 1)
         return r;
 
     ti = dm_table_get_target(map, 0);
     if (!ti->type->prepare_ioctl)
         return r;
 
     if (dm_suspended_md(md))
         return -EAGAIN;
 
     r = ti->type->prepare_ioctl(ti, bdev);
     if (r == -ENOTCONN && !fatal_signal_pending(current)) {
         dm_put_live_table(md, *srcu_idx);
         msleep(10);
         goto retry;
     }
 
     return r;
 }
 
 static void dm_unprepare_ioctl(struct mapped_device *md, int srcu_idx)
 {
     dm_put_live_table(md, srcu_idx);
 }
 
 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
             unsigned int cmd, unsigned long arg)
 {
     struct mapped_device *md = bdev->bd_disk->private_data;
     int r, srcu_idx;
 
     r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
     if (r < 0)
         goto out;
 
     if (r > 0) {
         /*
          * Target determined this ioctl is being issued against a
          * subset of the parent bdev; require extra privileges.
          */
         if (!capable(CAP_SYS_RAWIO)) {
             DMDEBUG_LIMIT(
     "%s: sending ioctl %x to DM device without required privilege.",
                 current->comm, cmd);
             r = -ENOIOCTLCMD;
             goto out;
         }
     }
 
     if (!bdev->bd_disk->fops->ioctl)
         r = -ENOTTY;
     else
         r = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
 out:
     dm_unprepare_ioctl(md, srcu_idx);
     return r;
 }
 
 u64 dm_start_time_ns_from_clone(struct bio *bio)
 {
     return jiffies_to_nsecs(clone_to_tio(bio)->io->start_time);
 }
 EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
 
 static bool bio_is_flush_with_data(struct bio *bio)
 {
     return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size);
 }
 
 static void dm_io_acct(struct dm_io *io, bool end)
 {
     struct dm_stats_aux *stats_aux = &io->stats_aux;
     unsigned long start_time = io->start_time;
     struct mapped_device *md = io->md;
     struct bio *bio = io->orig_bio;
     unsigned int sectors;
 
     /*
      * If REQ_PREFLUSH set, don't account payload, it will be
      * submitted (and accounted) after this flush completes.
      */
     if (bio_is_flush_with_data(bio))
         sectors = 0;
     else if (likely(!(dm_io_flagged(io, DM_IO_WAS_SPLIT))))
         sectors = bio_sectors(bio);
     else
         sectors = io->sectors;
 
     if (!end)
         bdev_start_io_acct(bio->bi_bdev, sectors, bio_op(bio),
                    start_time);
     else
         bdev_end_io_acct(bio->bi_bdev, bio_op(bio), start_time);
 
     if (static_branch_unlikely(&stats_enabled) &&
         unlikely(dm_stats_used(&md->stats))) {
         sector_t sector;
 
         if (likely(!dm_io_flagged(io, DM_IO_WAS_SPLIT)))
             sector = bio->bi_iter.bi_sector;
         else
             sector = bio_end_sector(bio) - io->sector_offset;
 
         dm_stats_account_io(&md->stats, bio_data_dir(bio),
                     sector, sectors,
                     end, start_time, stats_aux);
     }
 }
 
 static void __dm_start_io_acct(struct dm_io *io)
 {
     dm_io_acct(io, false);
 }
 
 static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
 {
     /*
      * Ensure IO accounting is only ever started once.
      */
     if (dm_io_flagged(io, DM_IO_ACCOUNTED))
         return;
 
     /* Expect no possibility for race unless DM_TIO_IS_DUPLICATE_BIO. */
     if (!clone || likely(dm_tio_is_normal(clone_to_tio(clone)))) {
         dm_io_set_flag(io, DM_IO_ACCOUNTED);
     } else {
         unsigned long flags;
         /* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */
         spin_lock_irqsave(&io->lock, flags);
         if (dm_io_flagged(io, DM_IO_ACCOUNTED)) {
             spin_unlock_irqrestore(&io->lock, flags);
             return;
         }
         dm_io_set_flag(io, DM_IO_ACCOUNTED);
         spin_unlock_irqrestore(&io->lock, flags);
     }
 
     __dm_start_io_acct(io);
 }
 
 static void dm_end_io_acct(struct dm_io *io)
 {
     dm_io_acct(io, true);
 }
 
 static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
 {
     struct dm_io *io;
     struct dm_target_io *tio;
     struct bio *clone;
 
     clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->mempools->io_bs);
     tio = clone_to_tio(clone);
     tio->flags = 0;
     dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO);
     tio->io = NULL;
 
     io = container_of(tio, struct dm_io, tio);
     io->magic = DM_IO_MAGIC;
     io->status = BLK_STS_OK;
 
     /* one ref is for submission, the other is for completion */
     atomic_set(&io->io_count, 2);
     this_cpu_inc(*md->pending_io);
     io->orig_bio = bio;
     io->md = md;
     spin_lock_init(&io->lock);
     io->start_time = jiffies;
     io->flags = 0;
 
     if (static_branch_unlikely(&stats_enabled))
         dm_stats_record_start(&md->stats, &io->stats_aux);
 
     return io;
 }
 
 static void free_io(struct dm_io *io)
 {
     bio_put(&io->tio.clone);
 }
 
 static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
                  unsigned target_bio_nr, unsigned *len, gfp_t gfp_mask)
 {
     struct mapped_device *md = ci->io->md;
     struct dm_target_io *tio;
     struct bio *clone;
 
     if (!ci->io->tio.io) {
         /* the dm_target_io embedded in ci->io is available */
         tio = &ci->io->tio;
         /* alloc_io() already initialized embedded clone */
         clone = &tio->clone;
     } else {
         clone = bio_alloc_clone(NULL, ci->bio, gfp_mask,
                     &md->mempools->bs);
         if (!clone)
             return NULL;
 
         /* REQ_DM_POLL_LIST shouldn't be inherited */
         clone->bi_opf &= ~REQ_DM_POLL_LIST;
 
         tio = clone_to_tio(clone);
         tio->flags = 0; /* also clears DM_TIO_INSIDE_DM_IO */
     }
 
     tio->magic = DM_TIO_MAGIC;
     tio->io = ci->io;
     tio->ti = ti;
     tio->target_bio_nr = target_bio_nr;
     tio->len_ptr = len;
     tio->old_sector = 0;
 
     /* Set default bdev, but target must bio_set_dev() before issuing IO */
     clone->bi_bdev = md->disk->part0;
     if (unlikely(ti->needs_bio_set_dev))
         bio_set_dev(clone, md->disk->part0);
 
     if (len) {
         clone->bi_iter.bi_size = to_bytes(*len);
         if (bio_integrity(clone))
             bio_integrity_trim(clone);
     }
 
     return clone;
 }
 
 static void free_tio(struct bio *clone)
 {
     if (dm_tio_flagged(clone_to_tio(clone), DM_TIO_INSIDE_DM_IO))
         return;
     bio_put(clone);
 }
 
 /*
  * Add the bio to the list of deferred io.
  */
 static void queue_io(struct mapped_device *md, struct bio *bio)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&md->deferred_lock, flags);
     bio_list_add(&md->deferred, bio);
     spin_unlock_irqrestore(&md->deferred_lock, flags);
     queue_work(md->wq, &md->work);
 }
 
 /*
  * Everyone (including functions in this file), should use this
  * function to access the md->map field, and make sure they call
  * dm_put_live_table() when finished.
  */
 struct dm_table *dm_get_live_table(struct mapped_device *md,
                    int *srcu_idx) __acquires(md->io_barrier)
 {
     *srcu_idx = srcu_read_lock(&md->io_barrier);
 
     return srcu_dereference(md->map, &md->io_barrier);
 }
 
 void dm_put_live_table(struct mapped_device *md,
                int srcu_idx) __releases(md->io_barrier)
 {
     srcu_read_unlock(&md->io_barrier, srcu_idx);
 }
 
 void dm_sync_table(struct mapped_device *md)
 {
     synchronize_srcu(&md->io_barrier);
     synchronize_rcu_expedited();
 }
 
 /*
  * A fast alternative to dm_get_live_table/dm_put_live_table.
  * The caller must not block between these two functions.
  */
 static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
 {
     rcu_read_lock();
     return rcu_dereference(md->map);
 }
 
 static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
 {
     rcu_read_unlock();
 }
 
 static inline struct dm_table *dm_get_live_table_bio(struct mapped_device *md,
                     int *srcu_idx, blk_opf_t bio_opf)
 {
     if (bio_opf & REQ_NOWAIT)
         return dm_get_live_table_fast(md);
     else
         return dm_get_live_table(md, srcu_idx);
 }
 
 static inline void dm_put_live_table_bio(struct mapped_device *md, int srcu_idx,
                      blk_opf_t bio_opf)
 {
     if (bio_opf & REQ_NOWAIT)
         dm_put_live_table_fast(md);
     else
         dm_put_live_table(md, srcu_idx);
 }
 
 static char *_dm_claim_ptr = "I belong to device-mapper";
 
 /*
  * Open a table device so we can use it as a map destination.
  */
 static int open_table_device(struct table_device *td, dev_t dev,
                  struct mapped_device *md)
 {
     struct block_device *bdev;
     u64 part_off;
     int r;
 
     BUG_ON(td->dm_dev.bdev);
 
     bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _dm_claim_ptr);
     if (IS_ERR(bdev))
         return PTR_ERR(bdev);
 
     r = bd_link_disk_holder(bdev, dm_disk(md));
     if (r) {
         blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
         return r;
     }
 
     td->dm_dev.bdev = bdev;
     td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev, &part_off, NULL, NULL);
     return 0;
 }
 
 /*
  * Close a table device that we've been using.
  */
 static void close_table_device(struct table_device *td, struct mapped_device *md)
 {
     if (!td->dm_dev.bdev)
         return;
 
     bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
     blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
     put_dax(td->dm_dev.dax_dev);
     td->dm_dev.bdev = NULL;
     td->dm_dev.dax_dev = NULL;
 }
 
 static struct table_device *find_table_device(struct list_head *l, dev_t dev,
                           fmode_t mode)
 {
     struct table_device *td;
 
     list_for_each_entry(td, l, list)
         if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
             return td;
 
     return NULL;
 }
 
 int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
             struct dm_dev **result)
 {
     int r;
     struct table_device *td;
 
     mutex_lock(&md->table_devices_lock);
     td = find_table_device(&md->table_devices, dev, mode);
     if (!td) {
         td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id);
         if (!td) {
             mutex_unlock(&md->table_devices_lock);
             return -ENOMEM;
         }
 
         td->dm_dev.mode = mode;
         td->dm_dev.bdev = NULL;
 
         if ((r = open_table_device(td, dev, md))) {
             mutex_unlock(&md->table_devices_lock);
             kfree(td);
             return r;
         }
 
         format_dev_t(td->dm_dev.name, dev);
 
         refcount_set(&td->count, 1);
         list_add(&td->list, &md->table_devices);
     } else {
         refcount_inc(&td->count);
     }
     mutex_unlock(&md->table_devices_lock);
 
     *result = &td->dm_dev;
     return 0;
 }
 
 void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
 {
     struct table_device *td = container_of(d, struct table_device, dm_dev);
 
     mutex_lock(&md->table_devices_lock);
     if (refcount_dec_and_test(&td->count)) {
         close_table_device(td, md);
         list_del(&td->list);
         kfree(td);
     }
     mutex_unlock(&md->table_devices_lock);
 }
 
 static void free_table_devices(struct list_head *devices)
 {
     struct list_head *tmp, *next;
 
     list_for_each_safe(tmp, next, devices) {
         struct table_device *td = list_entry(tmp, struct table_device, list);
 
         DMWARN("dm_destroy: %s still exists with %d references",
                td->dm_dev.name, refcount_read(&td->count));
         kfree(td);
     }
 }
 
 /*
  * Get the geometry associated with a dm device
  */
 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
 {
     *geo = md->geometry;
 
     return 0;
 }
 
 /*
  * Set the geometry of a device.
  */
 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
 {
     sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
 
     if (geo->start > sz) {
         DMWARN("Start sector is beyond the geometry limits.");
         return -EINVAL;
     }
 
     md->geometry = *geo;
 
     return 0;
 }
 
 static int __noflush_suspending(struct mapped_device *md)
 {
     return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
 }
 
 static void dm_requeue_add_io(struct dm_io *io, bool first_stage)
 {
     struct mapped_device *md = io->md;
 
     if (first_stage) {
         struct dm_io *next = md->requeue_list;
 
         md->requeue_list = io;
         io->next = next;
     } else {
         bio_list_add_head(&md->deferred, io->orig_bio);
     }
 }
 
 static void dm_kick_requeue(struct mapped_device *md, bool first_stage)
 {
     if (first_stage)
         queue_work(md->wq, &md->requeue_work);
     else
         queue_work(md->wq, &md->work);
 }
 
 /*
  * Return true if the dm_io's original bio is requeued.
  * io->status is updated with error if requeue disallowed.
  */
 static bool dm_handle_requeue(struct dm_io *io, bool first_stage)
 {
     struct bio *bio = io->orig_bio;
     bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE);
     bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) &&
                      (bio->bi_opf & REQ_POLLED));
     struct mapped_device *md = io->md;
     bool requeued = false;
 
     if (handle_requeue || handle_polled_eagain) {
         unsigned long flags;
 
         if (bio->bi_opf & REQ_POLLED) {
             /*
              * Upper layer won't help us poll split bio
              * (io->orig_bio may only reflect a subset of the
              * pre-split original) so clear REQ_POLLED.
              */
             bio_clear_polled(bio);
         }
 
         /*
          * Target requested pushing back the I/O or
          * polled IO hit BLK_STS_AGAIN.
          */
         spin_lock_irqsave(&md->deferred_lock, flags);
         if ((__noflush_suspending(md) &&
              !WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
             handle_polled_eagain || first_stage) {
             dm_requeue_add_io(io, first_stage);
             requeued = true;
         } else {
             /*
              * noflush suspend was interrupted or this is
              * a write to a zoned target.
              */
             io->status = BLK_STS_IOERR;
         }
         spin_unlock_irqrestore(&md->deferred_lock, flags);
     }
 
     if (requeued)
         dm_kick_requeue(md, first_stage);
 
     return requeued;
 }
 
 static void __dm_io_complete(struct dm_io *io, bool first_stage)
 {
     struct bio *bio = io->orig_bio;
     struct mapped_device *md = io->md;
     blk_status_t io_error;
     bool requeued;
 
     requeued = dm_handle_requeue(io, first_stage);
     if (requeued && first_stage)
         return;
 
     io_error = io->status;
     if (dm_io_flagged(io, DM_IO_ACCOUNTED))
         dm_end_io_acct(io);
     else if (!io_error) {
         /*
          * Must handle target that DM_MAPIO_SUBMITTED only to
          * then bio_endio() rather than dm_submit_bio_remap()
          */
         __dm_start_io_acct(io);
         dm_end_io_acct(io);
     }
     free_io(io);
     smp_wmb();
     this_cpu_dec(*md->pending_io);
 
     /* nudge anyone waiting on suspend queue */
     if (unlikely(wq_has_sleeper(&md->wait)))
         wake_up(&md->wait);
 
     /* Return early if the original bio was requeued */
     if (requeued)
         return;
 
     if (bio_is_flush_with_data(bio)) {
         /*
          * Preflush done for flush with data, reissue
          * without REQ_PREFLUSH.
          */
         bio->bi_opf &= ~REQ_PREFLUSH;
         queue_io(md, bio);
     } else {
         /* done with normal IO or empty flush */
         if (io_error)
             bio->bi_status = io_error;
         bio_endio(bio);
     }
 }
 
 static void dm_wq_requeue_work(struct work_struct *work)
 {
     struct mapped_device *md = container_of(work, struct mapped_device,
                         requeue_work);
     unsigned long flags;
     struct dm_io *io;
 
     /* reuse deferred lock to simplify dm_handle_requeue */
     spin_lock_irqsave(&md->deferred_lock, flags);
     io = md->requeue_list;
     md->requeue_list = NULL;
     spin_unlock_irqrestore(&md->deferred_lock, flags);
 
     while (io) {
         struct dm_io *next = io->next;
 
         dm_io_rewind(io, &md->disk->bio_split);
 
         io->next = NULL;
         __dm_io_complete(io, false);
         io = next;
     }
 }
 
 /*
  * Two staged requeue:
  *
  * 1) io->orig_bio points to the real original bio, and the part mapped to
  *    this io must be requeued, instead of other parts of the original bio.
  *
  * 2) io->orig_bio points to new cloned bio which matches the requeued dm_io.
  */
 static void dm_io_complete(struct dm_io *io)
 {
     bool first_requeue;
 
     /*
      * Only dm_io that has been split needs two stage requeue, otherwise
      * we may run into long bio clone chain during suspend and OOM could
      * be triggered.
      *
      * Also flush data dm_io won't be marked as DM_IO_WAS_SPLIT, so they
      * also aren't handled via the first stage requeue.
      */
     if (dm_io_flagged(io, DM_IO_WAS_SPLIT))
         first_requeue = true;
     else
         first_requeue = false;
 
     __dm_io_complete(io, first_requeue);
 }
 
 /*
  * Decrements the number of outstanding ios that a bio has been
  * cloned into, completing the original io if necc.
  */
 static inline void __dm_io_dec_pending(struct dm_io *io)
 {
     if (atomic_dec_and_test(&io->io_count))
         dm_io_complete(io);
 }
 
 static void dm_io_set_error(struct dm_io *io, blk_status_t error)
 {
     unsigned long flags;
 
     /* Push-back supersedes any I/O errors */
     spin_lock_irqsave(&io->lock, flags);
     if (!(io->status == BLK_STS_DM_REQUEUE &&
           __noflush_suspending(io->md))) {
         io->status = error;
     }
     spin_unlock_irqrestore(&io->lock, flags);
 }
 
 static void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
 {
     if (unlikely(error))
         dm_io_set_error(io, error);
 
     __dm_io_dec_pending(io);
 }
 
 void disable_discard(struct mapped_device *md)
 {
     struct queue_limits *limits = dm_get_queue_limits(md);
 
     /* device doesn't really support DISCARD, disable it */
     limits->max_discard_sectors = 0;
 }
 
 void disable_write_zeroes(struct mapped_device *md)
 {
     struct queue_limits *limits = dm_get_queue_limits(md);
 
     /* device doesn't really support WRITE ZEROES, disable it */
     limits->max_write_zeroes_sectors = 0;
 }
 
 static bool swap_bios_limit(struct dm_target *ti, struct bio *bio)
 {
     return unlikely((bio->bi_opf & REQ_SWAP) != 0) && unlikely(ti->limit_swap_bios);
 }
 
 static void clone_endio(struct bio *bio)
 {
     blk_status_t error = bio->bi_status;
     struct dm_target_io *tio = clone_to_tio(bio);
     struct dm_target *ti = tio->ti;
     dm_endio_fn endio = ti->type->end_io;
     struct dm_io *io = tio->io;
     struct mapped_device *md = io->md;
 
     if (unlikely(error == BLK_STS_TARGET)) {
         if (bio_op(bio) == REQ_OP_DISCARD &&
             !bdev_max_discard_sectors(bio->bi_bdev))
             disable_discard(md);
         else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
              !bdev_write_zeroes_sectors(bio->bi_bdev))
             disable_write_zeroes(md);
     }
 
     if (static_branch_unlikely(&zoned_enabled) &&
         unlikely(bdev_is_zoned(bio->bi_bdev)))
         dm_zone_endio(io, bio);
 
     if (endio) {
         int r = endio(ti, bio, &error);
         switch (r) {
         case DM_ENDIO_REQUEUE:
             if (static_branch_unlikely(&zoned_enabled)) {
                 /*
                  * Requeuing writes to a sequential zone of a zoned
                  * target will break the sequential write pattern:
                  * fail such IO.
                  */
                 if (WARN_ON_ONCE(dm_is_zone_write(md, bio)))
                     error = BLK_STS_IOERR;
                 else
                     error = BLK_STS_DM_REQUEUE;
             } else
                 error = BLK_STS_DM_REQUEUE;
             fallthrough;
         case DM_ENDIO_DONE:
             break;
         case DM_ENDIO_INCOMPLETE:
             /* The target will handle the io */
             return;
         default:
             DMWARN("unimplemented target endio return value: %d", r);
             BUG();
         }
     }
 
     if (static_branch_unlikely(&swap_bios_enabled) &&
         unlikely(swap_bios_limit(ti, bio)))
         up(&md->swap_bios_semaphore);
 
     free_tio(bio);
     dm_io_dec_pending(io, error);
 }
 
 /*
  * Return maximum size of I/O possible at the supplied sector up to the current
  * target boundary.
  */
 static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
                           sector_t target_offset)
 {
     return ti->len - target_offset;
 }
 
 static sector_t max_io_len(struct dm_target *ti, sector_t sector)
 {
     sector_t target_offset = dm_target_offset(ti, sector);
     sector_t len = max_io_len_target_boundary(ti, target_offset);
 
     /*
      * Does the target need to split IO even further?
      * - varied (per target) IO splitting is a tenet of DM; this
      *   explains why stacked chunk_sectors based splitting via
      *   bio_split_to_limits() isn't possible here.
      */
     if (!ti->max_io_len)
         return len;
     return min_t(sector_t, len,
         min(queue_max_sectors(ti->table->md->queue),
             blk_chunk_sectors_left(target_offset, ti->max_io_len)));
 }
 
 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
 {
     if (len > UINT_MAX) {
         DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
               (unsigned long long)len, UINT_MAX);
         ti->error = "Maximum size of target IO is too large";
         return -EINVAL;
     }
 
     ti->max_io_len = (uint32_t) len;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
 
 static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
                         sector_t sector, int *srcu_idx)
     __acquires(md->io_barrier)
 {
     struct dm_table *map;
     struct dm_target *ti;
 
     map = dm_get_live_table(md, srcu_idx);
     if (!map)
         return NULL;
 
     ti = dm_table_find_target(map, sector);
     if (!ti)
         return NULL;
 
     return ti;
 }
 
 static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
         long nr_pages, enum dax_access_mode mode, void **kaddr,
         pfn_t *pfn)
 {
     struct mapped_device *md = dax_get_private(dax_dev);
     sector_t sector = pgoff * PAGE_SECTORS;
     struct dm_target *ti;
     long len, ret = -EIO;
     int srcu_idx;
 
     ti = dm_dax_get_live_target(md, sector, &srcu_idx);
 
     if (!ti)
         goto out;
     if (!ti->type->direct_access)
         goto out;
     len = max_io_len(ti, sector) / PAGE_SECTORS;
     if (len < 1)
         goto out;
     nr_pages = min(len, nr_pages);
     ret = ti->type->direct_access(ti, pgoff, nr_pages, mode, kaddr, pfn);
 
  out:
     dm_put_live_table(md, srcu_idx);
 
     return ret;
 }
 
 static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
                   size_t nr_pages)
 {
     struct mapped_device *md = dax_get_private(dax_dev);
     sector_t sector = pgoff * PAGE_SECTORS;
     struct dm_target *ti;
     int ret = -EIO;
     int srcu_idx;
 
     ti = dm_dax_get_live_target(md, sector, &srcu_idx);
 
     if (!ti)
         goto out;
     if (WARN_ON(!ti->type->dax_zero_page_range)) {
         /*
          * ->zero_page_range() is mandatory dax operation. If we are
          *  here, something is wrong.
          */
         goto out;
     }
     ret = ti->type->dax_zero_page_range(ti, pgoff, nr_pages);
  out:
     dm_put_live_table(md, srcu_idx);
 
     return ret;
 }
 
 static size_t dm_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
         void *addr, size_t bytes, struct iov_iter *i)
 {
     struct mapped_device *md = dax_get_private(dax_dev);
     sector_t sector = pgoff * PAGE_SECTORS;
     struct dm_target *ti;
     int srcu_idx;
     long ret = 0;
 
     ti = dm_dax_get_live_target(md, sector, &srcu_idx);
     if (!ti || !ti->type->dax_recovery_write)
         goto out;
 
     ret = ti->type->dax_recovery_write(ti, pgoff, addr, bytes, i);
 out:
     dm_put_live_table(md, srcu_idx);
     return ret;
 }
 
 /*
  * A target may call dm_accept_partial_bio only from the map routine.  It is
  * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management
  * operations, REQ_OP_ZONE_APPEND (zone append writes) and any bio serviced by
  * __send_duplicate_bios().
  *
  * dm_accept_partial_bio informs the dm that the target only wants to process
  * additional n_sectors sectors of the bio and the rest of the data should be
  * sent in a next bio.
  *
  * A diagram that explains the arithmetics:
  * +--------------------+---------------+-------+
  * |         1          |       2       |   3   |
  * +--------------------+---------------+-------+
  *
  * <-------------- *tio->len_ptr --------------->
  *                      <----- bio_sectors ----->
  *                      <-- n_sectors -->
  *
  * Region 1 was already iterated over with bio_advance or similar function.
  *  (it may be empty if the target doesn't use bio_advance)
  * Region 2 is the remaining bio size that the target wants to process.
  *  (it may be empty if region 1 is non-empty, although there is no reason
  *   to make it empty)
  * The target requires that region 3 is to be sent in the next bio.
  *
  * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
  * the partially processed part (the sum of regions 1+2) must be the same for all
  * copies of the bio.
  */
 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
 {
     struct dm_target_io *tio = clone_to_tio(bio);
     struct dm_io *io = tio->io;
     unsigned bio_sectors = bio_sectors(bio);
 
     BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
     BUG_ON(op_is_zone_mgmt(bio_op(bio)));
     BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
     BUG_ON(bio_sectors > *tio->len_ptr);
     BUG_ON(n_sectors > bio_sectors);
 
     *tio->len_ptr -= bio_sectors - n_sectors;
     bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
 
     /*
      * __split_and_process_bio() may have already saved mapped part
      * for accounting but it is being reduced so update accordingly.
      */
     dm_io_set_flag(io, DM_IO_WAS_SPLIT);
     io->sectors = n_sectors;
     io->sector_offset = bio_sectors(io->orig_bio);
 }
 EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
 
 /*
  * @clone: clone bio that DM core passed to target's .map function
  * @tgt_clone: clone of @clone bio that target needs submitted
  *
  * Targets should use this interface to submit bios they take
  * ownership of when returning DM_MAPIO_SUBMITTED.
  *
  * Target should also enable ti->accounts_remapped_io
  */
 void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
 {
     struct dm_target_io *tio = clone_to_tio(clone);
     struct dm_io *io = tio->io;
 
     /* establish bio that will get submitted */
     if (!tgt_clone)
         tgt_clone = clone;
 
     /*
      * Account io->origin_bio to DM dev on behalf of target
      * that took ownership of IO with DM_MAPIO_SUBMITTED.
      */
     dm_start_io_acct(io, clone);
 
     trace_block_bio_remap(tgt_clone, disk_devt(io->md->disk),
                   tio->old_sector);
     submit_bio_noacct(tgt_clone);
 }
 EXPORT_SYMBOL_GPL(dm_submit_bio_remap);
 
 static noinline void __set_swap_bios_limit(struct mapped_device *md, int latch)
 {
     mutex_lock(&md->swap_bios_lock);
     while (latch < md->swap_bios) {
         cond_resched();
         down(&md->swap_bios_semaphore);
         md->swap_bios--;
     }
     while (latch > md->swap_bios) {
         cond_resched();
         up(&md->swap_bios_semaphore);
         md->swap_bios++;
     }
     mutex_unlock(&md->swap_bios_lock);
 }
 
 static void __map_bio(struct bio *clone)
 {
     struct dm_target_io *tio = clone_to_tio(clone);
     struct dm_target *ti = tio->ti;
     struct dm_io *io = tio->io;
     struct mapped_device *md = io->md;
     int r;
 
     clone->bi_end_io = clone_endio;
 
     /*
      * Map the clone.
      */
     tio->old_sector = clone->bi_iter.bi_sector;
 
     if (static_branch_unlikely(&swap_bios_enabled) &&
         unlikely(swap_bios_limit(ti, clone))) {
         int latch = get_swap_bios();
         if (unlikely(latch != md->swap_bios))
             __set_swap_bios_limit(md, latch);
         down(&md->swap_bios_semaphore);
     }
 
     if (static_branch_unlikely(&zoned_enabled)) {
         /*
          * Check if the IO needs a special mapping due to zone append
          * emulation on zoned target. In this case, dm_zone_map_bio()
          * calls the target map operation.
          */
         if (unlikely(dm_emulate_zone_append(md)))
             r = dm_zone_map_bio(tio);
         else
             r = ti->type->map(ti, clone);
     } else
         r = ti->type->map(ti, clone);
 
     switch (r) {
     case DM_MAPIO_SUBMITTED:
         /* target has assumed ownership of this io */
         if (!ti->accounts_remapped_io)
             dm_start_io_acct(io, clone);
         break;
     case DM_MAPIO_REMAPPED:
         dm_submit_bio_remap(clone, NULL);
         break;
     case DM_MAPIO_KILL:
     case DM_MAPIO_REQUEUE:
         if (static_branch_unlikely(&swap_bios_enabled) &&
             unlikely(swap_bios_limit(ti, clone)))
             up(&md->swap_bios_semaphore);
         free_tio(clone);
         if (r == DM_MAPIO_KILL)
             dm_io_dec_pending(io, BLK_STS_IOERR);
         else
             dm_io_dec_pending(io, BLK_STS_DM_REQUEUE);
         break;
     default:
         DMWARN("unimplemented target map return value: %d", r);
         BUG();
     }
 }
 
 static void setup_split_accounting(struct clone_info *ci, unsigned len)
 {
     struct dm_io *io = ci->io;
 
     if (ci->sector_count > len) {
         /*
          * Split needed, save the mapped part for accounting.
          * NOTE: dm_accept_partial_bio() will update accordingly.
          */
         dm_io_set_flag(io, DM_IO_WAS_SPLIT);
         io->sectors = len;
         io->sector_offset = bio_sectors(ci->bio);
     }
 }
 
 static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
                 struct dm_target *ti, unsigned num_bios)
 {
     struct bio *bio;
     int try;
 
     for (try = 0; try < 2; try++) {
         int bio_nr;
 
         if (try)
             mutex_lock(&ci->io->md->table_devices_lock);
         for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
             bio = alloc_tio(ci, ti, bio_nr, NULL,
                     try ? GFP_NOIO : GFP_NOWAIT);
             if (!bio)
                 break;
 
             bio_list_add(blist, bio);
         }
         if (try)
             mutex_unlock(&ci->io->md->table_devices_lock);
         if (bio_nr == num_bios)
             return;
 
         while ((bio = bio_list_pop(blist)))
             free_tio(bio);
     }
 }
 
 static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
                  unsigned int num_bios, unsigned *len)
 {
     struct bio_list blist = BIO_EMPTY_LIST;
     struct bio *clone;
     unsigned int ret = 0;
 
     switch (num_bios) {
     case 0:
         break;
     case 1:
         if (len)
             setup_split_accounting(ci, *len);
         clone = alloc_tio(ci, ti, 0, len, GFP_NOIO);
         __map_bio(clone);
         ret = 1;
         break;
     default:
         /* dm_accept_partial_bio() is not supported with shared tio->len_ptr */
         alloc_multiple_bios(&blist, ci, ti, num_bios);
         while ((clone = bio_list_pop(&blist))) {
             dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO);
             __map_bio(clone);
             ret += 1;
         }
         break;
     }
 
     return ret;
 }
 
 static void __send_empty_flush(struct clone_info *ci)
 {
     struct dm_table *t = ci->map;
     struct bio flush_bio;
 
     /*
      * Use an on-stack bio for this, it's safe since we don't
      * need to reference it after submit. It's just used as
      * the basis for the clone(s).
      */
     bio_init(&flush_bio, ci->io->md->disk->part0, NULL, 0,
          REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC);
 
     ci->bio = &flush_bio;
     ci->sector_count = 0;
     ci->io->tio.clone.bi_iter.bi_size = 0;
 
     for (unsigned int i = 0; i < t->num_targets; i++) {
         unsigned int bios;
         struct dm_target *ti = dm_table_get_target(t, i);
 
         atomic_add(ti->num_flush_bios, &ci->io->io_count);
         bios = __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
         atomic_sub(ti->num_flush_bios - bios, &ci->io->io_count);
     }
 
     /*
      * alloc_io() takes one extra reference for submission, so the
      * reference won't reach 0 without the following subtraction
      */
     atomic_sub(1, &ci->io->io_count);
 
     bio_uninit(ci->bio);
 }
 
 static void __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti,
                     unsigned num_bios)
 {
     unsigned len;
     unsigned int bios;
 
     len = min_t(sector_t, ci->sector_count,
             max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector)));
 
     atomic_add(num_bios, &ci->io->io_count);
     bios = __send_duplicate_bios(ci, ti, num_bios, &len);
     /*
      * alloc_io() takes one extra reference for submission, so the
      * reference won't reach 0 without the following (+1) subtraction
      */
     atomic_sub(num_bios - bios + 1, &ci->io->io_count);
 
     ci->sector += len;
     ci->sector_count -= len;
 }
 
 static bool is_abnormal_io(struct bio *bio)
 {
     enum req_op op = bio_op(bio);
 
     if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) {
         switch (op) {
         case REQ_OP_DISCARD:
         case REQ_OP_SECURE_ERASE:
         case REQ_OP_WRITE_ZEROES:
             return true;
         default:
             break;
         }
     }
 
     return false;
 }
 
 static blk_status_t __process_abnormal_io(struct clone_info *ci,
                       struct dm_target *ti)
 {
     unsigned num_bios = 0;
 
     switch (bio_op(ci->bio)) {
     case REQ_OP_DISCARD:
         num_bios = ti->num_discard_bios;
         break;
     case REQ_OP_SECURE_ERASE:
         num_bios = ti->num_secure_erase_bios;
         break;
     case REQ_OP_WRITE_ZEROES:
         num_bios = ti->num_write_zeroes_bios;
         break;
     default:
         break;
     }
 
     /*
      * Even though the device advertised support for this type of
      * request, that does not mean every target supports it, and
      * reconfiguration might also have changed that since the
      * check was performed.
      */
     if (unlikely(!num_bios))
         return BLK_STS_NOTSUPP;
 
     __send_changing_extent_only(ci, ti, num_bios);
     return BLK_STS_OK;
 }
 
 /*
  * Reuse ->bi_private as dm_io list head for storing all dm_io instances
  * associated with this bio, and this bio's bi_private needs to be
  * stored in dm_io->data before the reuse.
  *
  * bio->bi_private is owned by fs or upper layer, so block layer won't
  * touch it after splitting. Meantime it won't be changed by anyone after
  * bio is submitted. So this reuse is safe.
  */
 static inline struct dm_io **dm_poll_list_head(struct bio *bio)
 {
     return (struct dm_io **)&bio->bi_private;
 }
 
 static void dm_queue_poll_io(struct bio *bio, struct dm_io *io)
 {
     struct dm_io **head = dm_poll_list_head(bio);
 
     if (!(bio->bi_opf & REQ_DM_POLL_LIST)) {
         bio->bi_opf |= REQ_DM_POLL_LIST;
         /*
          * Save .bi_private into dm_io, so that we can reuse
          * .bi_private as dm_io list head for storing dm_io list
          */
         io->data = bio->bi_private;
 
         /* tell block layer to poll for completion */
         bio->bi_cookie = ~BLK_QC_T_NONE;
 
         io->next = NULL;
     } else {
         /*
          * bio recursed due to split, reuse original poll list,
          * and save bio->bi_private too.
          */
         io->data = (*head)->data;
         io->next = *head;
     }
 
     *head = io;
 }
 
 /*
  * Select the correct strategy for processing a non-flush bio.
  */
 static blk_status_t __split_and_process_bio(struct clone_info *ci)
 {
     struct bio *clone;
     struct dm_target *ti;
     unsigned len;
 
     ti = dm_table_find_target(ci->map, ci->sector);
     if (unlikely(!ti))
         return BLK_STS_IOERR;
 
     if (unlikely((ci->bio->bi_opf & REQ_NOWAIT) != 0) &&
         unlikely(!dm_target_supports_nowait(ti->type)))
         return BLK_STS_NOTSUPP;
 
     if (unlikely(ci->is_abnormal_io))
         return __process_abnormal_io(ci, ti);
 
     /*
      * Only support bio polling for normal IO, and the target io is
      * exactly inside the dm_io instance (verified in dm_poll_dm_io)
      */
     ci->submit_as_polled = !!(ci->bio->bi_opf & REQ_POLLED);
 
     len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
     setup_split_accounting(ci, len);
     clone = alloc_tio(ci, ti, 0, &len, GFP_NOIO);
     __map_bio(clone);
 
     ci->sector += len;
     ci->sector_count -= len;
 
     return BLK_STS_OK;
 }
 
 static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
                 struct dm_table *map, struct bio *bio, bool is_abnormal)
 {
     ci->map = map;
     ci->io = alloc_io(md, bio);
     ci->bio = bio;
     ci->is_abnormal_io = is_abnormal;
     ci->submit_as_polled = false;
     ci->sector = bio->bi_iter.bi_sector;
     ci->sector_count = bio_sectors(bio);
 
     /* Shouldn't happen but sector_count was being set to 0 so... */
     if (static_branch_unlikely(&zoned_enabled) &&
         WARN_ON_ONCE(op_is_zone_mgmt(bio_op(bio)) && ci->sector_count))
         ci->sector_count = 0;
 }
 
 /*
  * Entry point to split a bio into clones and submit them to the targets.
  */
 static void dm_split_and_process_bio(struct mapped_device *md,
                      struct dm_table *map, struct bio *bio)
 {
     struct clone_info ci;
     struct dm_io *io;
     blk_status_t error = BLK_STS_OK;
     bool is_abnormal;
 
     is_abnormal = is_abnormal_io(bio);
     if (unlikely(is_abnormal)) {
         /*
          * Use bio_split_to_limits() for abnormal IO (e.g. discard, etc)
          * otherwise associated queue_limits won't be imposed.
          */
         bio = bio_split_to_limits(bio);
     }
 
     init_clone_info(&ci, md, map, bio, is_abnormal);
     io = ci.io;
 
     if (bio->bi_opf & REQ_PREFLUSH) {
         __send_empty_flush(&ci);
         /* dm_io_complete submits any data associated with flush */
         goto out;
     }
 
     error = __split_and_process_bio(&ci);
     if (error || !ci.sector_count)
         goto out;
     /*
      * Remainder must be passed to submit_bio_noacct() so it gets handled
      * *after* bios already submitted have been completely processed.
      */
     bio_trim(bio, io->sectors, ci.sector_count);
     trace_block_split(bio, bio->bi_iter.bi_sector);
     bio_inc_remaining(bio);
     submit_bio_noacct(bio);
 out:
     /*
      * Drop the extra reference count for non-POLLED bio, and hold one
      * reference for POLLED bio, which will be released in dm_poll_bio
      *
      * Add every dm_io instance into the dm_io list head which is stored
      * in bio->bi_private, so that dm_poll_bio can poll them all.
      */
     if (error || !ci.submit_as_polled) {
         /*
          * In case of submission failure, the extra reference for
          * submitting io isn't consumed yet
          */
         if (error)
             atomic_dec(&io->io_count);
         dm_io_dec_pending(io, error);
     } else
         dm_queue_poll_io(bio, io);
 }
 
 static void dm_submit_bio(struct bio *bio)
 {
     struct mapped_device *md = bio->bi_bdev->bd_disk->private_data;
     int srcu_idx;
     struct dm_table *map;
     blk_opf_t bio_opf = bio->bi_opf;
 
     map = dm_get_live_table_bio(md, &srcu_idx, bio_opf);
 
     /* If suspended, or map not yet available, queue this IO for later */
     if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) ||
         unlikely(!map)) {
         if (bio->bi_opf & REQ_NOWAIT)
             bio_wouldblock_error(bio);
         else if (bio->bi_opf & REQ_RAHEAD)
             bio_io_error(bio);
         else
             queue_io(md, bio);
         goto out;
     }
 
     dm_split_and_process_bio(md, map, bio);
 out:
     dm_put_live_table_bio(md, srcu_idx, bio_opf);
 }
 
 static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob,
               unsigned int flags)
 {
     WARN_ON_ONCE(!dm_tio_is_normal(&io->tio));
 
     /* don't poll if the mapped io is done */
     if (atomic_read(&io->io_count) > 1)
         bio_poll(&io->tio.clone, iob, flags);
 
     /* bio_poll holds the last reference */
     return atomic_read(&io->io_count) == 1;
 }
 
 static int dm_poll_bio(struct bio *bio, struct io_comp_batch *iob,
                unsigned int flags)
 {
     struct dm_io **head = dm_poll_list_head(bio);
     struct dm_io *list = *head;
     struct dm_io *tmp = NULL;
     struct dm_io *curr, *next;
 
     /* Only poll normal bio which was marked as REQ_DM_POLL_LIST */
     if (!(bio->bi_opf & REQ_DM_POLL_LIST))
         return 0;
 
     WARN_ON_ONCE(!list);
 
     /*
      * Restore .bi_private before possibly completing dm_io.
      *
      * bio_poll() is only possible once @bio has been completely
      * submitted via submit_bio_noacct()'s depth-first submission.
      * So there is no dm_queue_poll_io() race associated with
      * clearing REQ_DM_POLL_LIST here.
      */
     bio->bi_opf &= ~REQ_DM_POLL_LIST;
     bio->bi_private = list->data;
 
     for (curr = list, next = curr->next; curr; curr = next, next =
             curr ? curr->next : NULL) {
         if (dm_poll_dm_io(curr, iob, flags)) {
             /*
              * clone_endio() has already occurred, so no
              * error handling is needed here.
              */
             __dm_io_dec_pending(curr);
         } else {
             curr->next = tmp;
             tmp = curr;
         }
     }
 
     /* Not done? */
     if (tmp) {
         bio->bi_opf |= REQ_DM_POLL_LIST;
         /* Reset bio->bi_private to dm_io list head */
         *head = tmp;
         return 0;
     }
     return 1;
 }
 
 /*-----------------------------------------------------------------
  * An IDR is used to keep track of allocated minor numbers.
  *---------------------------------------------------------------*/
 static void free_minor(int minor)
 {
     spin_lock(&_minor_lock);
     idr_remove(&_minor_idr, minor);
     spin_unlock(&_minor_lock);
 }
 
 /*
  * See if the device with a specific minor # is free.
  */
 static int specific_minor(int minor)
 {
     int r;
 
     if (minor >= (1 << MINORBITS))
         return -EINVAL;
 
     idr_preload(GFP_KERNEL);
     spin_lock(&_minor_lock);
 
     r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
 
     spin_unlock(&_minor_lock);
     idr_preload_end();
     if (r < 0)
         return r == -ENOSPC ? -EBUSY : r;
     return 0;
 }
 
 static int next_free_minor(int *minor)
 {
     int r;
 
     idr_preload(GFP_KERNEL);
     spin_lock(&_minor_lock);
 
     r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
 
     spin_unlock(&_minor_lock);
     idr_preload_end();
     if (r < 0)
         return r;
     *minor = r;
     return 0;
 }
 
 static const struct block_device_operations dm_blk_dops;
 static const struct block_device_operations dm_rq_blk_dops;
 static const struct dax_operations dm_dax_ops;
 
 static void dm_wq_work(struct work_struct *work);
 
 #ifdef CONFIG_BLK_INLINE_ENCRYPTION
 static void dm_queue_destroy_crypto_profile(struct request_queue *q)
 {
     dm_destroy_crypto_profile(q->crypto_profile);
 }
 
 #else /* CONFIG_BLK_INLINE_ENCRYPTION */
 
 static inline void dm_queue_destroy_crypto_profile(struct request_queue *q)
 {
 }
 #endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
 
 static void cleanup_mapped_device(struct mapped_device *md)
 {
     if (md->wq)
         destroy_workqueue(md->wq);
     dm_free_md_mempools(md->mempools);
 
     if (md->dax_dev) {
         dax_remove_host(md->disk);
         kill_dax(md->dax_dev);
         put_dax(md->dax_dev);
         md->dax_dev = NULL;
     }
 
     dm_cleanup_zoned_dev(md);
     if (md->disk) {
         spin_lock(&_minor_lock);
         md->disk->private_data = NULL;
         spin_unlock(&_minor_lock);
         if (dm_get_md_type(md) != DM_TYPE_NONE) {
             dm_sysfs_exit(md);
             del_gendisk(md->disk);
         }
         dm_queue_destroy_crypto_profile(md->queue);
         put_disk(md->disk);
     }
 
     if (md->pending_io) {
         free_percpu(md->pending_io);
         md->pending_io = NULL;
     }
 
     cleanup_srcu_struct(&md->io_barrier);
 
     mutex_destroy(&md->suspend_lock);
     mutex_destroy(&md->type_lock);
     mutex_destroy(&md->table_devices_lock);
     mutex_destroy(&md->swap_bios_lock);
 
     dm_mq_cleanup_mapped_device(md);
 }
 
 /*
  * Allocate and initialise a blank device with a given minor.
  */
 static struct mapped_device *alloc_dev(int minor)
 {
     int r, numa_node_id = dm_get_numa_node();
     struct mapped_device *md;
     void *old_md;
 
     md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
     if (!md) {
         DMWARN("unable to allocate device, out of memory.");
         return NULL;
     }
 
     if (!try_module_get(THIS_MODULE))
         goto bad_module_get;
 
     /* get a minor number for the dev */
     if (minor == DM_ANY_MINOR)
         r = next_free_minor(&minor);
     else
         r = specific_minor(minor);
     if (r < 0)
         goto bad_minor;
 
     r = init_srcu_struct(&md->io_barrier);
     if (r < 0)
         goto bad_io_barrier;
 
     md->numa_node_id = numa_node_id;
     md->init_tio_pdu = false;
     md->type = DM_TYPE_NONE;
     mutex_init(&md->suspend_lock);
     mutex_init(&md->type_lock);
     mutex_init(&md->table_devices_lock);
     spin_lock_init(&md->deferred_lock);
     atomic_set(&md->holders, 1);
     atomic_set(&md->open_count, 0);
     atomic_set(&md->event_nr, 0);
     atomic_set(&md->uevent_seq, 0);
     INIT_LIST_HEAD(&md->uevent_list);
     INIT_LIST_HEAD(&md->table_devices);
     spin_lock_init(&md->uevent_lock);
 
     /*
      * default to bio-based until DM table is loaded and md->type
      * established. If request-based table is loaded: blk-mq will
      * override accordingly.
      */
     md->disk = blk_alloc_disk(md->numa_node_id);
     if (!md->disk)
         goto bad;
     md->queue = md->disk->queue;
 
     init_waitqueue_head(&md->wait);
     INIT_WORK(&md->work, dm_wq_work);
     INIT_WORK(&md->requeue_work, dm_wq_requeue_work);
     init_waitqueue_head(&md->eventq);
     init_completion(&md->kobj_holder.completion);
 
     md->requeue_list = NULL;
     md->swap_bios = get_swap_bios();
     sema_init(&md->swap_bios_semaphore, md->swap_bios);
     mutex_init(&md->swap_bios_lock);
 
     md->disk->major = _major;
     md->disk->first_minor = minor;
     md->disk->minors = 1;
     md->disk->flags |= GENHD_FL_NO_PART;
     md->disk->fops = &dm_blk_dops;
     md->disk->queue = md->queue;
     md->disk->private_data = md;
     sprintf(md->disk->disk_name, "dm-%d", minor);
 
     if (IS_ENABLED(CONFIG_FS_DAX)) {
         md->dax_dev = alloc_dax(md, &dm_dax_ops);
         if (IS_ERR(md->dax_dev)) {
             md->dax_dev = NULL;
             goto bad;
         }
         set_dax_nocache(md->dax_dev);
         set_dax_nomc(md->dax_dev);
         if (dax_add_host(md->dax_dev, md->disk))
             goto bad;
     }
 
     format_dev_t(md->name, MKDEV(_major, minor));
 
     md->wq = alloc_workqueue("kdmflush/%s", WQ_MEM_RECLAIM, 0, md->name);
     if (!md->wq)
         goto bad;
 
     md->pending_io = alloc_percpu(unsigned long);
     if (!md->pending_io)
         goto bad;
 
     dm_stats_init(&md->stats);
 
     /* Populate the mapping, nobody knows we exist yet */
     spin_lock(&_minor_lock);
     old_md = idr_replace(&_minor_idr, md, minor);
     spin_unlock(&_minor_lock);
 
     BUG_ON(old_md != MINOR_ALLOCED);
 
     return md;
 
 bad:
     cleanup_mapped_device(md);
 bad_io_barrier:
     free_minor(minor);
 bad_minor:
     module_put(THIS_MODULE);
 bad_module_get:
     kvfree(md);
     return NULL;
 }
 
 static void unlock_fs(struct mapped_device *md);
 
 static void free_dev(struct mapped_device *md)
 {
     int minor = MINOR(disk_devt(md->disk));
 
     unlock_fs(md);
 
     cleanup_mapped_device(md);
 
     free_table_devices(&md->table_devices);
     dm_stats_cleanup(&md->stats);
     free_minor(minor);
 
     module_put(THIS_MODULE);
     kvfree(md);
 }
 
 /*
  * Bind a table to the device.
  */
 static void event_callback(void *context)
 {
     unsigned long flags;
     LIST_HEAD(uevents);
     struct mapped_device *md = (struct mapped_device *) context;
 
     spin_lock_irqsave(&md->uevent_lock, flags);
     list_splice_init(&md->uevent_list, &uevents);
     spin_unlock_irqrestore(&md->uevent_lock, flags);
 
     dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
 
     atomic_inc(&md->event_nr);
     wake_up(&md->eventq);
     dm_issue_global_event();
 }
 
 /*
  * Returns old map, which caller must destroy.
  */
 static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
                    struct queue_limits *limits)
 {
     struct dm_table *old_map;
     sector_t size;
     int ret;
 
     lockdep_assert_held(&md->suspend_lock);
 
     size = dm_table_get_size(t);
 
     /*
      * Wipe any geometry if the size of the table changed.
      */
     if (size != dm_get_size(md))
         memset(&md->geometry, 0, sizeof(md->geometry));
 
     if (!get_capacity(md->disk))
         set_capacity(md->disk, size);
     else
         set_capacity_and_notify(md->disk, size);
 
     dm_table_event_callback(t, event_callback, md);
 
     if (dm_table_request_based(t)) {
         /*
          * Leverage the fact that request-based DM targets are
          * immutable singletons - used to optimize dm_mq_queue_rq.
          */
         md->immutable_target = dm_table_get_immutable_target(t);
 
         /*
          * There is no need to reload with request-based dm because the
          * size of front_pad doesn't change.
          *
          * Note for future: If you are to reload bioset, prep-ed
          * requests in the queue may refer to bio from the old bioset,
          * so you must walk through the queue to unprep.
          */
         if (!md->mempools) {
             md->mempools = t->mempools;
             t->mempools = NULL;
         }
     } else {
         /*
          * The md may already have mempools that need changing.
          * If so, reload bioset because front_pad may have changed
          * because a different table was loaded.
          */
         dm_free_md_mempools(md->mempools);
         md->mempools = t->mempools;
         t->mempools = NULL;
     }
 
     ret = dm_table_set_restrictions(t, md->queue, limits);
     if (ret) {
         old_map = ERR_PTR(ret);
         goto out;
     }
 
     old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
     rcu_assign_pointer(md->map, (void *)t);
     md->immutable_target_type = dm_table_get_immutable_target_type(t);
 
     if (old_map)
         dm_sync_table(md);
 out:
     return old_map;
 }
 
 /*
  * Returns unbound table for the caller to free.
  */
 static struct dm_table *__unbind(struct mapped_device *md)
 {
     struct dm_table *map = rcu_dereference_protected(md->map, 1);
 
     if (!map)
         return NULL;
 
     dm_table_event_callback(map, NULL, NULL);
     RCU_INIT_POINTER(md->map, NULL);
     dm_sync_table(md);
 
     return map;
 }
 
 /*
  * Constructor for a new device.
  */
 int dm_create(int minor, struct mapped_device **result)
 {
     struct mapped_device *md;
 
     md = alloc_dev(minor);
     if (!md)
         return -ENXIO;
 
     dm_ima_reset_data(md);
 
     *result = md;
     return 0;
 }
 
 /*
  * Functions to manage md->type.
  * All are required to hold md->type_lock.
  */
 void dm_lock_md_type(struct mapped_device *md)
 {
     mutex_lock(&md->type_lock);
 }
 
 void dm_unlock_md_type(struct mapped_device *md)
 {
     mutex_unlock(&md->type_lock);
 }
 
 void dm_set_md_type(struct mapped_device *md, enum dm_queue_mode type)
 {
     BUG_ON(!mutex_is_locked(&md->type_lock));
     md->type = type;
 }
 
 enum dm_queue_mode dm_get_md_type(struct mapped_device *md)
 {
     return md->type;
 }
 
 struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
 {
     return md->immutable_target_type;
 }
 
 /*
  * The queue_limits are only valid as long as you have a reference
  * count on 'md'.
  */
 struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
 {
     BUG_ON(!atomic_read(&md->holders));
     return &md->queue->limits;
 }
 EXPORT_SYMBOL_GPL(dm_get_queue_limits);
 
 /*
  * Setup the DM device's queue based on md's type
  */
 int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 {
     enum dm_queue_mode type = dm_table_get_type(t);
     struct queue_limits limits;
     int r;
 
     switch (type) {
     case DM_TYPE_REQUEST_BASED:
         md->disk->fops = &dm_rq_blk_dops;
         r = dm_mq_init_request_queue(md, t);
         if (r) {
             DMERR("Cannot initialize queue for request-based dm mapped device");
             return r;
         }
         break;
     case DM_TYPE_BIO_BASED:
     case DM_TYPE_DAX_BIO_BASED:
         break;
     case DM_TYPE_NONE:
         WARN_ON_ONCE(true);
         break;
     }
 
     r = dm_calculate_queue_limits(t, &limits);
     if (r) {
         DMERR("Cannot calculate initial queue limits");
         return r;
     }
     r = dm_table_set_restrictions(t, md->queue, &limits);
     if (r)
         return r;
 
     r = add_disk(md->disk);
     if (r)
         return r;
 
     r = dm_sysfs_init(md);
     if (r) {
         del_gendisk(md->disk);
         return r;
     }
     md->type = type;
     return 0;
 }
 
 struct mapped_device *dm_get_md(dev_t dev)
 {
     struct mapped_device *md;
     unsigned minor = MINOR(dev);
 
     if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
         return NULL;
 
     spin_lock(&_minor_lock);
 
     md = idr_find(&_minor_idr, minor);
     if (!md || md == MINOR_ALLOCED || (MINOR(disk_devt(dm_disk(md))) != minor) ||
         test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
         md = NULL;
         goto out;
     }
     dm_get(md);
 out:
     spin_unlock(&_minor_lock);
 
     return md;
 }
 EXPORT_SYMBOL_GPL(dm_get_md);
 
 void *dm_get_mdptr(struct mapped_device *md)
 {
     return md->interface_ptr;
 }
 
 void dm_set_mdptr(struct mapped_device *md, void *ptr)
 {
     md->interface_ptr = ptr;
 }
 
 void dm_get(struct mapped_device *md)
 {
     atomic_inc(&md->holders);
     BUG_ON(test_bit(DMF_FREEING, &md->flags));
 }
 
 int dm_hold(struct mapped_device *md)
 {
     spin_lock(&_minor_lock);
     if (test_bit(DMF_FREEING, &md->flags)) {
         spin_unlock(&_minor_lock);
         return -EBUSY;
     }
     dm_get(md);
     spin_unlock(&_minor_lock);
     return 0;
 }
 EXPORT_SYMBOL_GPL(dm_hold);
 
 const char *dm_device_name(struct mapped_device *md)
 {
     return md->name;
 }
 EXPORT_SYMBOL_GPL(dm_device_name);
 
 static void __dm_destroy(struct mapped_device *md, bool wait)
 {
     struct dm_table *map;
     int srcu_idx;
 
     might_sleep();
 
     spin_lock(&_minor_lock);
     idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
     set_bit(DMF_FREEING, &md->flags);
     spin_unlock(&_minor_lock);
 
     blk_mark_disk_dead(md->disk);
 
     /*
      * Take suspend_lock so that presuspend and postsuspend methods
      * do not race with internal suspend.
      */
     mutex_lock(&md->suspend_lock);
     map = dm_get_live_table(md, &srcu_idx);
     if (!dm_suspended_md(md)) {
         dm_table_presuspend_targets(map);
         set_bit(DMF_SUSPENDED, &md->flags);
         set_bit(DMF_POST_SUSPENDING, &md->flags);
         dm_table_postsuspend_targets(map);
     }
     /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
     dm_put_live_table(md, srcu_idx);
     mutex_unlock(&md->suspend_lock);
 
     /*
      * Rare, but there may be I/O requests still going to complete,
      * for example.  Wait for all references to disappear.
      * No one should increment the reference count of the mapped_device,
      * after the mapped_device state becomes DMF_FREEING.
      */
     if (wait)
         while (atomic_read(&md->holders))
             msleep(1);
     else if (atomic_read(&md->holders))
         DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
                dm_device_name(md), atomic_read(&md->holders));
 
     dm_table_destroy(__unbind(md));
     free_dev(md);
 }
 
 void dm_destroy(struct mapped_device *md)
 {
     __dm_destroy(md, true);
 }
 
 void dm_destroy_immediate(struct mapped_device *md)
 {
     __dm_destroy(md, false);
 }
 
 void dm_put(struct mapped_device *md)
 {
     atomic_dec(&md->holders);
 }
 EXPORT_SYMBOL_GPL(dm_put);
 
 static bool dm_in_flight_bios(struct mapped_device *md)
 {
     int cpu;
     unsigned long sum = 0;
 
     for_each_possible_cpu(cpu)
         sum += *per_cpu_ptr(md->pending_io, cpu);
 
     return sum != 0;
 }
 
 static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int task_state)
 {
     int r = 0;
     DEFINE_WAIT(wait);
 
     while (true) {
         prepare_to_wait(&md->wait, &wait, task_state);
 
         if (!dm_in_flight_bios(md))
             break;
 
         if (signal_pending_state(task_state, current)) {
             r = -EINTR;
             break;
         }
 
         io_schedule();
     }
     finish_wait(&md->wait, &wait);
 
     smp_rmb();
 
     return r;
 }
 
 static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_state)
 {
     int r = 0;
 
     if (!queue_is_mq(md->queue))
         return dm_wait_for_bios_completion(md, task_state);
 
     while (true) {
         if (!blk_mq_queue_inflight(md->queue))
             break;
 
         if (signal_pending_state(task_state, current)) {
             r = -EINTR;
             break;
         }
 
         msleep(5);
     }
 
     return r;
 }
 
 /*
  * Process the deferred bios
  */
 static void dm_wq_work(struct work_struct *work)
 {
     struct mapped_device *md = container_of(work, struct mapped_device, work);
     struct bio *bio;
 
     while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
         spin_lock_irq(&md->deferred_lock);
         bio = bio_list_pop(&md->deferred);
         spin_unlock_irq(&md->deferred_lock);
 
         if (!bio)
             break;
 
         submit_bio_noacct(bio);
     }
 }
 
 static void dm_queue_flush(struct mapped_device *md)
 {
     clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
     smp_mb__after_atomic();
     queue_work(md->wq, &md->work);
 }
 
 /*
  * Swap in a new table, returning the old one for the caller to destroy.
  */
 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
 {
     struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
     struct queue_limits limits;
     int r;
 
     mutex_lock(&md->suspend_lock);
 
     /* device must be suspended */
     if (!dm_suspended_md(md))
         goto out;
 
     /*
      * If the new table has no data devices, retain the existing limits.
      * This helps multipath with queue_if_no_path if all paths disappear,
      * then new I/O is queued based on these limits, and then some paths
      * reappear.
      */
     if (dm_table_has_no_data_devices(table)) {
         live_map = dm_get_live_table_fast(md);
         if (live_map)
             limits = md->queue->limits;
         dm_put_live_table_fast(md);
     }
 
     if (!live_map) {
         r = dm_calculate_queue_limits(table, &limits);
         if (r) {
             map = ERR_PTR(r);
             goto out;
         }
     }
 
     map = __bind(md, table, &limits);
     dm_issue_global_event();
 
 out:
     mutex_unlock(&md->suspend_lock);
     return map;
 }
 
 /*
  * Functions to lock and unlock any filesystem running on the
  * device.
  */
 static int lock_fs(struct mapped_device *md)
 {
     int r;
 
     WARN_ON(test_bit(DMF_FROZEN, &md->flags));
 
     r = freeze_bdev(md->disk->part0);
     if (!r)
         set_bit(DMF_FROZEN, &md->flags);
     return r;
 }
 
 static void unlock_fs(struct mapped_device *md)
 {
     if (!test_bit(DMF_FROZEN, &md->flags))
         return;
     thaw_bdev(md->disk->part0);
     clear_bit(DMF_FROZEN, &md->flags);
 }
 
 /*
  * @suspend_flags: DM_SUSPEND_LOCKFS_FLAG and/or DM_SUSPEND_NOFLUSH_FLAG
  * @task_state: e.g. TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE
  * @dmf_suspended_flag: DMF_SUSPENDED or DMF_SUSPENDED_INTERNALLY
  *
  * If __dm_suspend returns 0, the device is completely quiescent
  * now. There is no request-processing activity. All new requests
  * are being added to md->deferred list.
  */
 static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
             unsigned suspend_flags, unsigned int task_state,
             int dmf_suspended_flag)
 {
     bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
     bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
     int r;
 
     lockdep_assert_held(&md->suspend_lock);
 
     /*
      * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
      * This flag is cleared before dm_suspend returns.
      */
     if (noflush)
         set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
     else
         DMDEBUG("%s: suspending with flush", dm_device_name(md));
 
     /*
      * This gets reverted if there's an error later and the targets
      * provide the .presuspend_undo hook.
      */
     dm_table_presuspend_targets(map);
 
     /*
      * Flush I/O to the device.
      * Any I/O submitted after lock_fs() may not be flushed.
      * noflush takes precedence over do_lockfs.
      * (lock_fs() flushes I/Os and waits for them to complete.)
      */
     if (!noflush && do_lockfs) {
         r = lock_fs(md);
         if (r) {
             dm_table_presuspend_undo_targets(map);
             return r;
         }
     }
 
     /*
      * Here we must make sure that no processes are submitting requests
      * to target drivers i.e. no one may be executing
      * dm_split_and_process_bio from dm_submit_bio.
      *
      * To get all processes out of dm_split_and_process_bio in dm_submit_bio,
      * we take the write lock. To prevent any process from reentering
      * dm_split_and_process_bio from dm_submit_bio and quiesce the thread
      * (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND and call
      * flush_workqueue(md->wq).
      */
     set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
     if (map)
         synchronize_srcu(&md->io_barrier);
 
     /*
      * Stop md->queue before flushing md->wq in case request-based
      * dm defers requests to md->wq from md->queue.
      */
     if (dm_request_based(md))
         dm_stop_queue(md->queue);
 
     flush_workqueue(md->wq);
 
     /*
      * At this point no more requests are entering target request routines.
      * We call dm_wait_for_completion to wait for all existing requests
      * to finish.
      */
     r = dm_wait_for_completion(md, task_state);
     if (!r)
         set_bit(dmf_suspended_flag, &md->flags);
 
     if (noflush)
         clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
     if (map)
         synchronize_srcu(&md->io_barrier);
 
     /* were we interrupted ? */
     if (r < 0) {
         dm_queue_flush(md);
 
         if (dm_request_based(md))
             dm_start_queue(md->queue);
 
         unlock_fs(md);
         dm_table_presuspend_undo_targets(map);
         /* pushback list is already flushed, so skip flush */
     }
 
     return r;
 }
 
 /*
  * We need to be able to change a mapping table under a mounted
  * filesystem.  For example we might want to move some data in
  * the background.  Before the table can be swapped with
  * dm_bind_table, dm_suspend must be called to flush any in
  * flight bios and ensure that any further io gets deferred.
  */
 /*
  * Suspend mechanism in request-based dm.
  *
  * 1. Flush all I/Os by lock_fs() if needed.
  * 2. Stop dispatching any I/O by stopping the request_queue.
  * 3. Wait for all in-flight I/Os to be completed or requeued.
  *
  * To abort suspend, start the request_queue.
  */
 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 {
     struct dm_table *map = NULL;
     int r = 0;
 
 retry:
     mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
 
     if (dm_suspended_md(md)) {
         r = -EINVAL;
         goto out_unlock;
     }
 
     if (dm_suspended_internally_md(md)) {
         /* already internally suspended, wait for internal resume */
         mutex_unlock(&md->suspend_lock);
         r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
         if (r)
             return r;
         goto retry;
     }
 
     map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
 
     r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED);
     if (r)
         goto out_unlock;
 
     set_bit(DMF_POST_SUSPENDING, &md->flags);
     dm_table_postsuspend_targets(map);
     clear_bit(DMF_POST_SUSPENDING, &md->flags);
 
 out_unlock:
     mutex_unlock(&md->suspend_lock);
     return r;
 }
 
 static int __dm_resume(struct mapped_device *md, struct dm_table *map)
 {
     if (map) {
         int r = dm_table_resume_targets(map);
         if (r)
             return r;
     }
 
     dm_queue_flush(md);
 
     /*
      * Flushing deferred I/Os must be done after targets are resumed
      * so that mapping of targets can work correctly.
      * Request-based dm is queueing the deferred I/Os in its request_queue.
      */
     if (dm_request_based(md))
         dm_start_queue(md->queue);
 
     unlock_fs(md);
 
     return 0;
 }
 
 int dm_resume(struct mapped_device *md)
 {
     int r;
     struct dm_table *map = NULL;
 
 retry:
     r = -EINVAL;
     mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
 
     if (!dm_suspended_md(md))
         goto out;
 
     if (dm_suspended_internally_md(md)) {
         /* already internally suspended, wait for internal resume */
         mutex_unlock(&md->suspend_lock);
         r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
         if (r)
             return r;
         goto retry;
     }
 
     map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
     if (!map || !dm_table_get_size(map))
         goto out;
 
     r = __dm_resume(md, map);
     if (r)
         goto out;
 
     clear_bit(DMF_SUSPENDED, &md->flags);
 out:
     mutex_unlock(&md->suspend_lock);
 
     return r;
 }
 
 /*
  * Internal suspend/resume works like userspace-driven suspend. It waits
  * until all bios finish and prevents issuing new bios to the target drivers.
  * It may be used only from the kernel.
  */
 
 static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
 {
     struct dm_table *map = NULL;
 
     lockdep_assert_held(&md->suspend_lock);
 
     if (md->internal_suspend_count++)
         return; /* nested internal suspend */
 
     if (dm_suspended_md(md)) {
         set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
         return; /* nest suspend */
     }
 
     map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
 
     /*
      * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
      * supported.  Properly supporting a TASK_INTERRUPTIBLE internal suspend
      * would require changing .presuspend to return an error -- avoid this
      * until there is a need for more elaborate variants of internal suspend.
      */
     (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE,
                 DMF_SUSPENDED_INTERNALLY);
 
     set_bit(DMF_POST_SUSPENDING, &md->flags);
     dm_table_postsuspend_targets(map);
     clear_bit(DMF_POST_SUSPENDING, &md->flags);
 }
 
 static void __dm_internal_resume(struct mapped_device *md)
 {
     BUG_ON(!md->internal_suspend_count);
 
     if (--md->internal_suspend_count)
         return; /* resume from nested internal suspend */
 
     if (dm_suspended_md(md))
         goto done; /* resume from nested suspend */
 
     /*
      * NOTE: existing callers don't need to call dm_table_resume_targets
      * (which may fail -- so best to avoid it for now by passing NULL map)
      */
     (void) __dm_resume(md, NULL);
 
 done:
     clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
     smp_mb__after_atomic();
     wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
 }
 
 void dm_internal_suspend_noflush(struct mapped_device *md)
 {
     mutex_lock(&md->suspend_lock);
     __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
     mutex_unlock(&md->suspend_lock);
 }
 EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
 
 void dm_internal_resume(struct mapped_device *md)
 {
     mutex_lock(&md->suspend_lock);
     __dm_internal_resume(md);
     mutex_unlock(&md->suspend_lock);
 }
 EXPORT_SYMBOL_GPL(dm_internal_resume);
 
 /*
  * Fast variants of internal suspend/resume hold md->suspend_lock,
  * which prevents interaction with userspace-driven suspend.
  */
 
 void dm_internal_suspend_fast(struct mapped_device *md)
 {
     mutex_lock(&md->suspend_lock);
     if (dm_suspended_md(md) || dm_suspended_internally_md(md))
         return;
 
     set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
     synchronize_srcu(&md->io_barrier);
     flush_workqueue(md->wq);
     dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
 
 void dm_internal_resume_fast(struct mapped_device *md)
 {
     if (dm_suspended_md(md) || dm_suspended_internally_md(md))
         goto done;
 
     dm_queue_flush(md);
 
 done:
     mutex_unlock(&md->suspend_lock);
 }
 EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
 
 /*-----------------------------------------------------------------
  * Event notification.
  *---------------------------------------------------------------*/
 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
                unsigned cookie)
 {
     int r;
     unsigned noio_flag;
     char udev_cookie[DM_COOKIE_LENGTH];
     char *envp[] = { udev_cookie, NULL };
 
     noio_flag = memalloc_noio_save();
 
     if (!cookie)
         r = kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
     else {
         snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
              DM_COOKIE_ENV_VAR_NAME, cookie);
         r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
                        action, envp);
     }
 
     memalloc_noio_restore(noio_flag);
 
     return r;
 }
 
 uint32_t dm_next_uevent_seq(struct mapped_device *md)
 {
     return atomic_add_return(1, &md->uevent_seq);
 }
 
 uint32_t dm_get_event_nr(struct mapped_device *md)
 {
     return atomic_read(&md->event_nr);
 }
 
 int dm_wait_event(struct mapped_device *md, int event_nr)
 {
     return wait_event_interruptible(md->eventq,
             (event_nr != atomic_read(&md->event_nr)));
 }
 
 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&md->uevent_lock, flags);
     list_add(elist, &md->uevent_list);
     spin_unlock_irqrestore(&md->uevent_lock, flags);
 }
 
 /*
  * The gendisk is only valid as long as you have a reference
  * count on 'md'.
  */
 struct gendisk *dm_disk(struct mapped_device *md)
 {
     return md->disk;
 }
 EXPORT_SYMBOL_GPL(dm_disk);
 
 struct kobject *dm_kobject(struct mapped_device *md)
 {
     return &md->kobj_holder.kobj;
 }
 
 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
 {
     struct mapped_device *md;
 
     md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
 
     spin_lock(&_minor_lock);
     if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
         md = NULL;
         goto out;
     }
     dm_get(md);
 out:
     spin_unlock(&_minor_lock);
 
     return md;
 }
 
 int dm_suspended_md(struct mapped_device *md)
 {
     return test_bit(DMF_SUSPENDED, &md->flags);
 }
 
 static int dm_post_suspending_md(struct mapped_device *md)
 {
     return test_bit(DMF_POST_SUSPENDING, &md->flags);
 }
 
 int dm_suspended_internally_md(struct mapped_device *md)
 {
     return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
 }
 
 int dm_test_deferred_remove_flag(struct mapped_device *md)
 {
     return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
 }
 
 int dm_suspended(struct dm_target *ti)
 {
     return dm_suspended_md(ti->table->md);
 }
 EXPORT_SYMBOL_GPL(dm_suspended);
 
 int dm_post_suspending(struct dm_target *ti)
 {
     return dm_post_suspending_md(ti->table->md);
 }
 EXPORT_SYMBOL_GPL(dm_post_suspending);
 
 int dm_noflush_suspending(struct dm_target *ti)
 {
     return __noflush_suspending(ti->table->md);
 }
 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
 
 void dm_free_md_mempools(struct dm_md_mempools *pools)
 {
     if (!pools)
         return;
 
     bioset_exit(&pools->bs);
     bioset_exit(&pools->io_bs);
 
     kfree(pools);
 }
 
 struct dm_pr {
     u64 old_key;
     u64 new_key;
     u32 flags;
     bool    abort;
     bool    fail_early;
     int ret;
     enum pr_type type;
 };
 
 static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
               struct dm_pr *pr)
 {
     struct mapped_device *md = bdev->bd_disk->private_data;
     struct dm_table *table;
     struct dm_target *ti;
     int ret = -ENOTTY, srcu_idx;
 
     table = dm_get_live_table(md, &srcu_idx);
     if (!table || !dm_table_get_size(table))
         goto out;
 
     /* We only support devices that have a single target */
     if (table->num_targets != 1)
         goto out;
     ti = dm_table_get_target(table, 0);
 
     if (dm_suspended_md(md)) {
         ret = -EAGAIN;
         goto out;
     }
 
     ret = -EINVAL;
     if (!ti->type->iterate_devices)
         goto out;
 
     ti->type->iterate_devices(ti, fn, pr);
     ret = 0;
 out:
     dm_put_live_table(md, srcu_idx);
     return ret;
 }
 
 /*
  * For register / unregister we need to manually call out to every path.
  */
 static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev,
                 sector_t start, sector_t len, void *data)
 {
     struct dm_pr *pr = data;
     const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
     int ret;
 
     if (!ops || !ops->pr_register) {
         pr->ret = -EOPNOTSUPP;
         return -1;
     }
 
     ret = ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
     if (!ret)
         return 0;
 
     if (!pr->ret)
         pr->ret = ret;
 
     if (pr->fail_early)
         return -1;
 
     return 0;
 }
 
 static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
               u32 flags)
 {
     struct dm_pr pr = {
         .old_key    = old_key,
         .new_key    = new_key,
         .flags      = flags,
         .fail_early = true,
         .ret        = 0,
     };
     int ret;
 
     ret = dm_call_pr(bdev, __dm_pr_register, &pr);
     if (ret) {
         /* Didn't even get to register a path */
         return ret;
     }
 
     if (!pr.ret)
         return 0;
     ret = pr.ret;
 
     if (!new_key)
         return ret;
 
     /* unregister all paths if we failed to register any path */
     pr.old_key = new_key;
     pr.new_key = 0;
     pr.flags = 0;
     pr.fail_early = false;
     (void) dm_call_pr(bdev, __dm_pr_register, &pr);
     return ret;
 }
 
 
 static int __dm_pr_reserve(struct dm_target *ti, struct dm_dev *dev,
                sector_t start, sector_t len, void *data)
 {
     struct dm_pr *pr = data;
     const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
 
     if (!ops || !ops->pr_reserve) {
         pr->ret = -EOPNOTSUPP;
         return -1;
     }
 
     pr->ret = ops->pr_reserve(dev->bdev, pr->old_key, pr->type, pr->flags);
     if (!pr->ret)
         return -1;
 
     return 0;
 }
 
 static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
              u32 flags)
 {
     struct dm_pr pr = {
         .old_key    = key,
         .flags      = flags,
         .type       = type,
         .fail_early = false,
         .ret        = 0,
     };
     int ret;
 
     ret = dm_call_pr(bdev, __dm_pr_reserve, &pr);
     if (ret)
         return ret;
 
     return pr.ret;
 }
 
 /*
  * If there is a non-All Registrants type of reservation, the release must be
  * sent down the holding path. For the cases where there is no reservation or
  * the path is not the holder the device will also return success, so we must
  * try each path to make sure we got the correct path.
  */
 static int __dm_pr_release(struct dm_target *ti, struct dm_dev *dev,
                sector_t start, sector_t len, void *data)
 {
     struct dm_pr *pr = data;
     const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
 
     if (!ops || !ops->pr_release) {
         pr->ret = -EOPNOTSUPP;
         return -1;
     }
 
     pr->ret = ops->pr_release(dev->bdev, pr->old_key, pr->type);
     if (pr->ret)
         return -1;
 
     return 0;
 }
 
 static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
 {
     struct dm_pr pr = {
         .old_key    = key,
         .type       = type,
         .fail_early = false,
     };
     int ret;
 
     ret = dm_call_pr(bdev, __dm_pr_release, &pr);
     if (ret)
         return ret;
 
     return pr.ret;
 }
 
 static int __dm_pr_preempt(struct dm_target *ti, struct dm_dev *dev,
                sector_t start, sector_t len, void *data)
 {
     struct dm_pr *pr = data;
     const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
 
     if (!ops || !ops->pr_preempt) {
         pr->ret = -EOPNOTSUPP;
         return -1;
     }
 
     pr->ret = ops->pr_preempt(dev->bdev, pr->old_key, pr->new_key, pr->type,
                   pr->abort);
     if (!pr->ret)
         return -1;
 
     return 0;
 }
 
 static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
              enum pr_type type, bool abort)
 {
     struct dm_pr pr = {
         .new_key    = new_key,
         .old_key    = old_key,
         .type       = type,
         .fail_early = false,
     };
     int ret;
 
     ret = dm_call_pr(bdev, __dm_pr_preempt, &pr);
     if (ret)
         return ret;
 
     return pr.ret;
 }
 
 static int dm_pr_clear(struct block_device *bdev, u64 key)
 {
     struct mapped_device *md = bdev->bd_disk->private_data;
     const struct pr_ops *ops;
     int r, srcu_idx;
 
     r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
     if (r < 0)
         goto out;
 
     ops = bdev->bd_disk->fops->pr_ops;
     if (ops && ops->pr_clear)
         r = ops->pr_clear(bdev, key);
     else
         r = -EOPNOTSUPP;
 out:
     dm_unprepare_ioctl(md, srcu_idx);
     return r;
 }
 
 static const struct pr_ops dm_pr_ops = {
     .pr_register    = dm_pr_register,
     .pr_reserve = dm_pr_reserve,
     .pr_release = dm_pr_release,
     .pr_preempt = dm_pr_preempt,
     .pr_clear   = dm_pr_clear,
 };
 
 static const struct block_device_operations dm_blk_dops = {
     .submit_bio = dm_submit_bio,
     .poll_bio = dm_poll_bio,
     .open = dm_blk_open,
     .release = dm_blk_close,
     .ioctl = dm_blk_ioctl,
     .getgeo = dm_blk_getgeo,
     .report_zones = dm_blk_report_zones,
     .pr_ops = &dm_pr_ops,
     .owner = THIS_MODULE
 };
 
 static const struct block_device_operations dm_rq_blk_dops = {
     .open = dm_blk_open,
     .release = dm_blk_close,
     .ioctl = dm_blk_ioctl,
     .getgeo = dm_blk_getgeo,
     .pr_ops = &dm_pr_ops,
     .owner = THIS_MODULE
 };
 
 static const struct dax_operations dm_dax_ops = {
     .direct_access = dm_dax_direct_access,
     .zero_page_range = dm_dax_zero_page_range,
     .recovery_write = dm_dax_recovery_write,
 };
 
 /*
  * module hooks
  */
 module_init(dm_init);
 module_exit(dm_exit);
 
 module_param(major, uint, 0);
 MODULE_PARM_DESC(major, "The major number of the device mapper");
 
 module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
 
 module_param(dm_numa_node, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(dm_numa_node, "NUMA node for DM device memory allocations");
 
 module_param(swap_bios, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(swap_bios, "Maximum allowed inflight swap IOs");
 
 MODULE_DESCRIPTION(DM_NAME " driver");
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");