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 /*
  * Copyright (C) 2001 Sistina Software (UK) Limited.
  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
  *
  * This file is released under the LGPL.
  */
 
 #ifndef _LINUX_DEVICE_MAPPER_H
 #define _LINUX_DEVICE_MAPPER_H
 
 #include <linux/bio.h>
 #include <linux/blkdev.h>
 #include <linux/dm-ioctl.h>
 #include <linux/math64.h>
 #include <linux/ratelimit.h>
 
 struct dm_dev;
 struct dm_target;
 struct dm_table;
 struct dm_report_zones_args;
 struct mapped_device;
 struct bio_vec;
 enum dax_access_mode;
 
 /*
  * Type of table, mapped_device's mempool and request_queue
  */
 enum dm_queue_mode {
     DM_TYPE_NONE         = 0,
     DM_TYPE_BIO_BASED    = 1,
     DM_TYPE_REQUEST_BASED    = 2,
     DM_TYPE_DAX_BIO_BASED    = 3,
 };
 
 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE, STATUSTYPE_IMA } status_type_t;
 
 union map_info {
     void *ptr;
 };
 
 /*
  * In the constructor the target parameter will already have the
  * table, type, begin and len fields filled in.
  */
 typedef int (*dm_ctr_fn) (struct dm_target *target,
               unsigned int argc, char **argv);
 
 /*
  * The destructor doesn't need to free the dm_target, just
  * anything hidden ti->private.
  */
 typedef void (*dm_dtr_fn) (struct dm_target *ti);
 
 /*
  * The map function must return:
  * < 0: error
  * = 0: The target will handle the io by resubmitting it later
  * = 1: simple remap complete
  * = 2: The target wants to push back the io
  */
 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
                         struct request *rq,
                         union map_info *map_context,
                         struct request **clone);
 typedef void (*dm_release_clone_request_fn) (struct request *clone,
                          union map_info *map_context);
 
 /*
  * Returns:
  * < 0 : error (currently ignored)
  * 0   : ended successfully
  * 1   : for some reason the io has still not completed (eg,
  *       multipath target might want to requeue a failed io).
  * 2   : The target wants to push back the io
  */
 typedef int (*dm_endio_fn) (struct dm_target *ti,
                 struct bio *bio, blk_status_t *error);
 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
                     struct request *clone, blk_status_t error,
                     union map_info *map_context);
 
 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
 typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
 typedef int (*dm_preresume_fn) (struct dm_target *ti);
 typedef void (*dm_resume_fn) (struct dm_target *ti);
 
 typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
                   unsigned status_flags, char *result, unsigned maxlen);
 
 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv,
                   char *result, unsigned maxlen);
 
 typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev);
 
 #ifdef CONFIG_BLK_DEV_ZONED
 typedef int (*dm_report_zones_fn) (struct dm_target *ti,
                    struct dm_report_zones_args *args,
                    unsigned int nr_zones);
 #else
 /*
  * Define dm_report_zones_fn so that targets can assign to NULL if
  * CONFIG_BLK_DEV_ZONED disabled. Otherwise each target needs to do
  * awkward #ifdefs in their target_type, etc.
  */
 typedef int (*dm_report_zones_fn) (struct dm_target *dummy);
 #endif
 
 /*
  * These iteration functions are typically used to check (and combine)
  * properties of underlying devices.
  * E.g. Does at least one underlying device support flush?
  *      Does any underlying device not support WRITE_SAME?
  *
  * The callout function is called once for each contiguous section of
  * an underlying device.  State can be maintained in *data.
  * Return non-zero to stop iterating through any further devices.
  */
 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
                        struct dm_dev *dev,
                        sector_t start, sector_t len,
                        void *data);
 
 /*
  * This function must iterate through each section of device used by the
  * target until it encounters a non-zero return code, which it then returns.
  * Returns zero if no callout returned non-zero.
  */
 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
                       iterate_devices_callout_fn fn,
                       void *data);
 
 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
                 struct queue_limits *limits);
 
 /*
  * Returns:
  *    0: The target can handle the next I/O immediately.
  *    1: The target can't handle the next I/O immediately.
  */
 typedef int (*dm_busy_fn) (struct dm_target *ti);
 
 /*
  * Returns:
  *  < 0 : error
  * >= 0 : the number of bytes accessible at the address
  */
 typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
         long nr_pages, enum dax_access_mode node, void **kaddr,
         pfn_t *pfn);
 typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
         size_t nr_pages);
 
 /*
  * Returns:
  * != 0 : number of bytes transferred
  * 0    : recovery write failed
  */
 typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
         void *addr, size_t bytes, struct iov_iter *i);
 
 void dm_error(const char *message);
 
 struct dm_dev {
     struct block_device *bdev;
     struct dax_device *dax_dev;
     fmode_t mode;
     char name[16];
 };
 
 dev_t dm_get_dev_t(const char *path);
 
 /*
  * Constructors should call these functions to ensure destination devices
  * are opened/closed correctly.
  */
 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
           struct dm_dev **result);
 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
 
 /*
  * Information about a target type
  */
 
 struct target_type {
     uint64_t features;
     const char *name;
     struct module *module;
     unsigned version[3];
     dm_ctr_fn ctr;
     dm_dtr_fn dtr;
     dm_map_fn map;
     dm_clone_and_map_request_fn clone_and_map_rq;
     dm_release_clone_request_fn release_clone_rq;
     dm_endio_fn end_io;
     dm_request_endio_fn rq_end_io;
     dm_presuspend_fn presuspend;
     dm_presuspend_undo_fn presuspend_undo;
     dm_postsuspend_fn postsuspend;
     dm_preresume_fn preresume;
     dm_resume_fn resume;
     dm_status_fn status;
     dm_message_fn message;
     dm_prepare_ioctl_fn prepare_ioctl;
     dm_report_zones_fn report_zones;
     dm_busy_fn busy;
     dm_iterate_devices_fn iterate_devices;
     dm_io_hints_fn io_hints;
     dm_dax_direct_access_fn direct_access;
     dm_dax_zero_page_range_fn dax_zero_page_range;
     dm_dax_recovery_write_fn dax_recovery_write;
 
     /* For internal device-mapper use. */
     struct list_head list;
 };
 
 /*
  * Target features
  */
 
 /*
  * Any table that contains an instance of this target must have only one.
  */
 #define DM_TARGET_SINGLETON     0x00000001
 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
 
 /*
  * Indicates that a target does not support read-only devices.
  */
 #define DM_TARGET_ALWAYS_WRITEABLE  0x00000002
 #define dm_target_always_writeable(type) \
         ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
 
 /*
  * Any device that contains a table with an instance of this target may never
  * have tables containing any different target type.
  */
 #define DM_TARGET_IMMUTABLE     0x00000004
 #define dm_target_is_immutable(type)    ((type)->features & DM_TARGET_IMMUTABLE)
 
 /*
  * Indicates that a target may replace any target; even immutable targets.
  * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
  */
 #define DM_TARGET_WILDCARD      0x00000008
 #define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
 
 /*
  * A target implements own bio data integrity.
  */
 #define DM_TARGET_INTEGRITY     0x00000010
 #define dm_target_has_integrity(type)   ((type)->features & DM_TARGET_INTEGRITY)
 
 /*
  * A target passes integrity data to the lower device.
  */
 #define DM_TARGET_PASSES_INTEGRITY  0x00000020
 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
 
 /*
  * Indicates support for zoned block devices:
  * - DM_TARGET_ZONED_HM: the target also supports host-managed zoned
  *   block devices but does not support combining different zoned models.
  * - DM_TARGET_MIXED_ZONED_MODEL: the target supports combining multiple
  *   devices with different zoned models.
  */
 #ifdef CONFIG_BLK_DEV_ZONED
 #define DM_TARGET_ZONED_HM      0x00000040
 #define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM)
 #else
 #define DM_TARGET_ZONED_HM      0x00000000
 #define dm_target_supports_zoned_hm(type) (false)
 #endif
 
 /*
  * A target handles REQ_NOWAIT
  */
 #define DM_TARGET_NOWAIT        0x00000080
 #define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT)
 
 /*
  * A target supports passing through inline crypto support.
  */
 #define DM_TARGET_PASSES_CRYPTO     0x00000100
 #define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO)
 
 #ifdef CONFIG_BLK_DEV_ZONED
 #define DM_TARGET_MIXED_ZONED_MODEL 0x00000200
 #define dm_target_supports_mixed_zoned_model(type) \
     ((type)->features & DM_TARGET_MIXED_ZONED_MODEL)
 #else
 #define DM_TARGET_MIXED_ZONED_MODEL 0x00000000
 #define dm_target_supports_mixed_zoned_model(type) (false)
 #endif
 
 struct dm_target {
     struct dm_table *table;
     struct target_type *type;
 
     /* target limits */
     sector_t begin;
     sector_t len;
 
     /* If non-zero, maximum size of I/O submitted to a target. */
     uint32_t max_io_len;
 
     /*
      * A number of zero-length barrier bios that will be submitted
      * to the target for the purpose of flushing cache.
      *
      * The bio number can be accessed with dm_bio_get_target_bio_nr.
      * It is a responsibility of the target driver to remap these bios
      * to the real underlying devices.
      */
     unsigned num_flush_bios;
 
     /*
      * The number of discard bios that will be submitted to the target.
      * The bio number can be accessed with dm_bio_get_target_bio_nr.
      */
     unsigned num_discard_bios;
 
     /*
      * The number of secure erase bios that will be submitted to the target.
      * The bio number can be accessed with dm_bio_get_target_bio_nr.
      */
     unsigned num_secure_erase_bios;
 
     /*
      * The number of WRITE ZEROES bios that will be submitted to the target.
      * The bio number can be accessed with dm_bio_get_target_bio_nr.
      */
     unsigned num_write_zeroes_bios;
 
     /*
      * The minimum number of extra bytes allocated in each io for the
      * target to use.
      */
     unsigned per_io_data_size;
 
     /* target specific data */
     void *private;
 
     /* Used to provide an error string from the ctr */
     char *error;
 
     /*
      * Set if this target needs to receive flushes regardless of
      * whether or not its underlying devices have support.
      */
     bool flush_supported:1;
 
     /*
      * Set if this target needs to receive discards regardless of
      * whether or not its underlying devices have support.
      */
     bool discards_supported:1;
 
     /*
      * Set if we need to limit the number of in-flight bios when swapping.
      */
     bool limit_swap_bios:1;
 
     /*
      * Set if this target implements a zoned device and needs emulation of
      * zone append operations using regular writes.
      */
     bool emulate_zone_append:1;
 
     /*
      * Set if the target will submit IO using dm_submit_bio_remap()
      * after returning DM_MAPIO_SUBMITTED from its map function.
      */
     bool accounts_remapped_io:1;
 
     /*
      * Set if the target will submit the DM bio without first calling
      * bio_set_dev(). NOTE: ideally a target should _not_ need this.
      */
     bool needs_bio_set_dev:1;
 };
 
 void *dm_per_bio_data(struct bio *bio, size_t data_size);
 struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size);
 unsigned dm_bio_get_target_bio_nr(const struct bio *bio);
 
 u64 dm_start_time_ns_from_clone(struct bio *bio);
 
 int dm_register_target(struct target_type *t);
 void dm_unregister_target(struct target_type *t);
 
 /*
  * Target argument parsing.
  */
 struct dm_arg_set {
     unsigned argc;
     char **argv;
 };
 
 /*
  * The minimum and maximum value of a numeric argument, together with
  * the error message to use if the number is found to be outside that range.
  */
 struct dm_arg {
     unsigned min;
     unsigned max;
     char *error;
 };
 
 /*
  * Validate the next argument, either returning it as *value or, if invalid,
  * returning -EINVAL and setting *error.
  */
 int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
         unsigned *value, char **error);
 
 /*
  * Process the next argument as the start of a group containing between
  * arg->min and arg->max further arguments. Either return the size as
  * *num_args or, if invalid, return -EINVAL and set *error.
  */
 int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
               unsigned *num_args, char **error);
 
 /*
  * Return the current argument and shift to the next.
  */
 const char *dm_shift_arg(struct dm_arg_set *as);
 
 /*
  * Move through num_args arguments.
  */
 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
 
 /*-----------------------------------------------------------------
  * Functions for creating and manipulating mapped devices.
  * Drop the reference with dm_put when you finish with the object.
  *---------------------------------------------------------------*/
 
 /*
  * DM_ANY_MINOR chooses the next available minor number.
  */
 #define DM_ANY_MINOR (-1)
 int dm_create(int minor, struct mapped_device **md);
 
 /*
  * Reference counting for md.
  */
 struct mapped_device *dm_get_md(dev_t dev);
 void dm_get(struct mapped_device *md);
 int dm_hold(struct mapped_device *md);
 void dm_put(struct mapped_device *md);
 
 /*
  * An arbitrary pointer may be stored alongside a mapped device.
  */
 void dm_set_mdptr(struct mapped_device *md, void *ptr);
 void *dm_get_mdptr(struct mapped_device *md);
 
 /*
  * A device can still be used while suspended, but I/O is deferred.
  */
 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
 int dm_resume(struct mapped_device *md);
 
 /*
  * Event functions.
  */
 uint32_t dm_get_event_nr(struct mapped_device *md);
 int dm_wait_event(struct mapped_device *md, int event_nr);
 uint32_t dm_next_uevent_seq(struct mapped_device *md);
 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
 
 /*
  * Info functions.
  */
 const char *dm_device_name(struct mapped_device *md);
 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
 struct gendisk *dm_disk(struct mapped_device *md);
 int dm_suspended(struct dm_target *ti);
 int dm_post_suspending(struct dm_target *ti);
 int dm_noflush_suspending(struct dm_target *ti);
 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
 void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone);
 union map_info *dm_get_rq_mapinfo(struct request *rq);
 
 #ifdef CONFIG_BLK_DEV_ZONED
 struct dm_report_zones_args {
     struct dm_target *tgt;
     sector_t next_sector;
 
     void *orig_data;
     report_zones_cb orig_cb;
     unsigned int zone_idx;
 
     /* must be filled by ->report_zones before calling dm_report_zones_cb */
     sector_t start;
 };
 int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
             struct dm_report_zones_args *args, unsigned int nr_zones);
 #endif /* CONFIG_BLK_DEV_ZONED */
 
 /*
  * Device mapper functions to parse and create devices specified by the
  * parameter "dm-mod.create="
  */
 int __init dm_early_create(struct dm_ioctl *dmi,
                struct dm_target_spec **spec_array,
                char **target_params_array);
 
 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
 
 /*
  * Geometry functions.
  */
 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
 
 /*-----------------------------------------------------------------
  * Functions for manipulating device-mapper tables.
  *---------------------------------------------------------------*/
 
 /*
  * First create an empty table.
  */
 int dm_table_create(struct dm_table **result, fmode_t mode,
             unsigned num_targets, struct mapped_device *md);
 
 /*
  * Then call this once for each target.
  */
 int dm_table_add_target(struct dm_table *t, const char *type,
             sector_t start, sector_t len, char *params);
 
 /*
  * Target can use this to set the table's type.
  * Can only ever be called from a target's ctr.
  * Useful for "hybrid" target (supports both bio-based
  * and request-based).
  */
 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
 
 /*
  * Finally call this to make the table ready for use.
  */
 int dm_table_complete(struct dm_table *t);
 
 /*
  * Destroy the table when finished.
  */
 void dm_table_destroy(struct dm_table *t);
 
 /*
  * Target may require that it is never sent I/O larger than len.
  */
 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
 
 /*
  * Table reference counting.
  */
 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
 void dm_sync_table(struct mapped_device *md);
 
 /*
  * Queries
  */
 sector_t dm_table_get_size(struct dm_table *t);
 fmode_t dm_table_get_mode(struct dm_table *t);
 struct mapped_device *dm_table_get_md(struct dm_table *t);
 const char *dm_table_device_name(struct dm_table *t);
 
 /*
  * Trigger an event.
  */
 void dm_table_event(struct dm_table *t);
 
 /*
  * Run the queue for request-based targets.
  */
 void dm_table_run_md_queue_async(struct dm_table *t);
 
 /*
  * The device must be suspended before calling this method.
  * Returns the previous table, which the caller must destroy.
  */
 struct dm_table *dm_swap_table(struct mapped_device *md,
                    struct dm_table *t);
 
 /*
  * Table blk_crypto_profile functions
  */
 void dm_destroy_crypto_profile(struct blk_crypto_profile *profile);
 
 /*-----------------------------------------------------------------
  * Macros.
  *---------------------------------------------------------------*/
 #define DM_NAME "device-mapper"
 
 #define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n"
 
 #define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__)
 
 #define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__)
 #define DMERR_LIMIT(fmt, ...) pr_err_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 #define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__)
 #define DMWARN_LIMIT(fmt, ...) pr_warn_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 #define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
 #define DMINFO_LIMIT(fmt, ...) pr_info_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 
 #define DMDEBUG(fmt, ...) pr_debug(DM_FMT(fmt), ##__VA_ARGS__)
 #define DMDEBUG_LIMIT(fmt, ...) pr_debug_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 
 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
               0 : scnprintf(result + sz, maxlen - sz, x))
 
 #define DMEMIT_TARGET_NAME_VERSION(y) \
         DMEMIT("target_name=%s,target_version=%u.%u.%u", \
                (y)->name, (y)->version[0], (y)->version[1], (y)->version[2])
 
 /*
  * Definitions of return values from target end_io function.
  */
 #define DM_ENDIO_DONE       0
 #define DM_ENDIO_INCOMPLETE 1
 #define DM_ENDIO_REQUEUE    2
 #define DM_ENDIO_DELAY_REQUEUE  3
 
 /*
  * Definitions of return values from target map function.
  */
 #define DM_MAPIO_SUBMITTED  0
 #define DM_MAPIO_REMAPPED   1
 #define DM_MAPIO_REQUEUE    DM_ENDIO_REQUEUE
 #define DM_MAPIO_DELAY_REQUEUE  DM_ENDIO_DELAY_REQUEUE
 #define DM_MAPIO_KILL       4
 
 #define dm_sector_div64(x, y)( \
 { \
     u64 _res; \
     (x) = div64_u64_rem(x, y, &_res); \
     _res; \
 } \
 )
 
 /*
  * Ceiling(n / sz)
  */
 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
 
 #define dm_sector_div_up(n, sz) ( \
 { \
     sector_t _r = ((n) + (sz) - 1); \
     sector_div(_r, (sz)); \
     _r; \
 } \
 )
 
 /*
  * ceiling(n / size) * size
  */
 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
 
 /*
  * Sector offset taken relative to the start of the target instead of
  * relative to the start of the device.
  */
 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
 
 static inline sector_t to_sector(unsigned long long n)
 {
     return (n >> SECTOR_SHIFT);
 }
 
 static inline unsigned long to_bytes(sector_t n)
 {
     return (n << SECTOR_SHIFT);
 }
 
 #endif  /* _LINUX_DEVICE_MAPPER_H */

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