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![Mike Snitzer](/assets/img/avatar_default.png)
There is no need for DM to export a wrapper around the already exported blk_lld_busy(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
608 lines
16 KiB
C
608 lines
16 KiB
C
/*
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* Copyright (C) 2001 Sistina Software (UK) Limited.
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* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef _LINUX_DEVICE_MAPPER_H
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#define _LINUX_DEVICE_MAPPER_H
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/math64.h>
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#include <linux/ratelimit.h>
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struct dm_dev;
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struct dm_target;
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struct dm_table;
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struct mapped_device;
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struct bio_vec;
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typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
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union map_info {
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void *ptr;
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};
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/*
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* In the constructor the target parameter will already have the
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* table, type, begin and len fields filled in.
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*/
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typedef int (*dm_ctr_fn) (struct dm_target *target,
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unsigned int argc, char **argv);
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/*
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* The destructor doesn't need to free the dm_target, just
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* anything hidden ti->private.
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*/
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typedef void (*dm_dtr_fn) (struct dm_target *ti);
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/*
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* The map function must return:
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* < 0: error
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* = 0: The target will handle the io by resubmitting it later
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* = 1: simple remap complete
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* = 2: The target wants to push back the io
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*/
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typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
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typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
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union map_info *map_context);
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typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
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struct request *rq,
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union map_info *map_context,
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struct request **clone);
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typedef void (*dm_release_clone_request_fn) (struct request *clone);
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/*
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* Returns:
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* < 0 : error (currently ignored)
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* 0 : ended successfully
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* 1 : for some reason the io has still not completed (eg,
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* multipath target might want to requeue a failed io).
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* 2 : The target wants to push back the io
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*/
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typedef int (*dm_endio_fn) (struct dm_target *ti,
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struct bio *bio, int error);
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typedef int (*dm_request_endio_fn) (struct dm_target *ti,
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struct request *clone, int error,
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union map_info *map_context);
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typedef void (*dm_presuspend_fn) (struct dm_target *ti);
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typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
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typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
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typedef int (*dm_preresume_fn) (struct dm_target *ti);
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typedef void (*dm_resume_fn) (struct dm_target *ti);
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typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
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unsigned status_flags, char *result, unsigned maxlen);
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typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
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typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
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unsigned long arg);
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typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
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struct bio_vec *biovec, int max_size);
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/*
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* These iteration functions are typically used to check (and combine)
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* properties of underlying devices.
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* E.g. Does at least one underlying device support flush?
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* Does any underlying device not support WRITE_SAME?
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*
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* The callout function is called once for each contiguous section of
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* an underlying device. State can be maintained in *data.
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* Return non-zero to stop iterating through any further devices.
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*/
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typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
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struct dm_dev *dev,
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sector_t start, sector_t len,
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void *data);
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/*
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* This function must iterate through each section of device used by the
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* target until it encounters a non-zero return code, which it then returns.
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* Returns zero if no callout returned non-zero.
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*/
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typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
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iterate_devices_callout_fn fn,
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void *data);
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typedef void (*dm_io_hints_fn) (struct dm_target *ti,
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struct queue_limits *limits);
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/*
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* Returns:
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* 0: The target can handle the next I/O immediately.
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* 1: The target can't handle the next I/O immediately.
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*/
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typedef int (*dm_busy_fn) (struct dm_target *ti);
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void dm_error(const char *message);
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struct dm_dev {
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struct block_device *bdev;
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fmode_t mode;
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char name[16];
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};
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/*
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* Constructors should call these functions to ensure destination devices
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* are opened/closed correctly.
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*/
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int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
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struct dm_dev **result);
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void dm_put_device(struct dm_target *ti, struct dm_dev *d);
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/*
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* Information about a target type
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*/
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struct target_type {
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uint64_t features;
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const char *name;
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struct module *module;
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unsigned version[3];
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dm_ctr_fn ctr;
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dm_dtr_fn dtr;
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dm_map_fn map;
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dm_map_request_fn map_rq;
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dm_clone_and_map_request_fn clone_and_map_rq;
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dm_release_clone_request_fn release_clone_rq;
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dm_endio_fn end_io;
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dm_request_endio_fn rq_end_io;
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dm_presuspend_fn presuspend;
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dm_presuspend_undo_fn presuspend_undo;
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dm_postsuspend_fn postsuspend;
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dm_preresume_fn preresume;
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dm_resume_fn resume;
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dm_status_fn status;
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dm_message_fn message;
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dm_ioctl_fn ioctl;
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dm_merge_fn merge;
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dm_busy_fn busy;
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dm_iterate_devices_fn iterate_devices;
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dm_io_hints_fn io_hints;
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/* For internal device-mapper use. */
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struct list_head list;
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};
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/*
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* Target features
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*/
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/*
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* Any table that contains an instance of this target must have only one.
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*/
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#define DM_TARGET_SINGLETON 0x00000001
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#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
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/*
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* Indicates that a target does not support read-only devices.
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*/
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#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
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#define dm_target_always_writeable(type) \
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((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
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/*
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* Any device that contains a table with an instance of this target may never
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* have tables containing any different target type.
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*/
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#define DM_TARGET_IMMUTABLE 0x00000004
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#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
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/*
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* Some targets need to be sent the same WRITE bio severals times so
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* that they can send copies of it to different devices. This function
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* examines any supplied bio and returns the number of copies of it the
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* target requires.
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*/
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typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
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struct dm_target {
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struct dm_table *table;
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struct target_type *type;
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/* target limits */
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sector_t begin;
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sector_t len;
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/* If non-zero, maximum size of I/O submitted to a target. */
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uint32_t max_io_len;
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/*
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* A number of zero-length barrier bios that will be submitted
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* to the target for the purpose of flushing cache.
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*
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* The bio number can be accessed with dm_bio_get_target_bio_nr.
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* It is a responsibility of the target driver to remap these bios
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* to the real underlying devices.
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*/
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unsigned num_flush_bios;
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/*
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* The number of discard bios that will be submitted to the target.
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* The bio number can be accessed with dm_bio_get_target_bio_nr.
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*/
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unsigned num_discard_bios;
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/*
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* The number of WRITE SAME bios that will be submitted to the target.
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* The bio number can be accessed with dm_bio_get_target_bio_nr.
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*/
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unsigned num_write_same_bios;
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/*
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* The minimum number of extra bytes allocated in each bio for the
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* target to use. dm_per_bio_data returns the data location.
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*/
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unsigned per_bio_data_size;
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/*
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* If defined, this function is called to find out how many
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* duplicate bios should be sent to the target when writing
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* data.
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*/
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dm_num_write_bios_fn num_write_bios;
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/* target specific data */
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void *private;
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/* Used to provide an error string from the ctr */
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char *error;
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/*
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* Set if this target needs to receive flushes regardless of
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* whether or not its underlying devices have support.
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*/
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bool flush_supported:1;
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/*
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* Set if this target needs to receive discards regardless of
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* whether or not its underlying devices have support.
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*/
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bool discards_supported:1;
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/*
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* Set if the target required discard bios to be split
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* on max_io_len boundary.
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*/
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bool split_discard_bios:1;
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/*
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* Set if this target does not return zeroes on discarded blocks.
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*/
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bool discard_zeroes_data_unsupported:1;
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};
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/* Each target can link one of these into the table */
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struct dm_target_callbacks {
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struct list_head list;
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int (*congested_fn) (struct dm_target_callbacks *, int);
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};
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/*
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* For bio-based dm.
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* One of these is allocated for each bio.
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* This structure shouldn't be touched directly by target drivers.
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* It is here so that we can inline dm_per_bio_data and
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* dm_bio_from_per_bio_data
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*/
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struct dm_target_io {
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struct dm_io *io;
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struct dm_target *ti;
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unsigned target_bio_nr;
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unsigned *len_ptr;
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struct bio clone;
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};
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static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
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{
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return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
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}
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static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
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{
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return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
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}
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static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
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{
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return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
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}
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int dm_register_target(struct target_type *t);
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void dm_unregister_target(struct target_type *t);
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/*
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* Target argument parsing.
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*/
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struct dm_arg_set {
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unsigned argc;
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char **argv;
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};
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/*
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* The minimum and maximum value of a numeric argument, together with
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* the error message to use if the number is found to be outside that range.
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*/
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struct dm_arg {
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unsigned min;
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unsigned max;
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char *error;
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};
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/*
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* Validate the next argument, either returning it as *value or, if invalid,
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* returning -EINVAL and setting *error.
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*/
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int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
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unsigned *value, char **error);
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/*
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* Process the next argument as the start of a group containing between
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* arg->min and arg->max further arguments. Either return the size as
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* *num_args or, if invalid, return -EINVAL and set *error.
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*/
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int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
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unsigned *num_args, char **error);
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/*
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* Return the current argument and shift to the next.
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*/
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const char *dm_shift_arg(struct dm_arg_set *as);
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/*
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* Move through num_args arguments.
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*/
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void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
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/*-----------------------------------------------------------------
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* Functions for creating and manipulating mapped devices.
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* Drop the reference with dm_put when you finish with the object.
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*---------------------------------------------------------------*/
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/*
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* DM_ANY_MINOR chooses the next available minor number.
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*/
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#define DM_ANY_MINOR (-1)
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int dm_create(int minor, struct mapped_device **md);
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/*
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* Reference counting for md.
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*/
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struct mapped_device *dm_get_md(dev_t dev);
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void dm_get(struct mapped_device *md);
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int dm_hold(struct mapped_device *md);
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void dm_put(struct mapped_device *md);
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/*
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* An arbitrary pointer may be stored alongside a mapped device.
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*/
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void dm_set_mdptr(struct mapped_device *md, void *ptr);
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void *dm_get_mdptr(struct mapped_device *md);
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/*
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* A device can still be used while suspended, but I/O is deferred.
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*/
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int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
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int dm_resume(struct mapped_device *md);
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/*
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* Event functions.
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*/
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uint32_t dm_get_event_nr(struct mapped_device *md);
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int dm_wait_event(struct mapped_device *md, int event_nr);
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uint32_t dm_next_uevent_seq(struct mapped_device *md);
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void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
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/*
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* Info functions.
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*/
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const char *dm_device_name(struct mapped_device *md);
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int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
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struct gendisk *dm_disk(struct mapped_device *md);
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int dm_suspended(struct dm_target *ti);
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int dm_noflush_suspending(struct dm_target *ti);
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void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
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union map_info *dm_get_rq_mapinfo(struct request *rq);
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struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
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/*
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* Geometry functions.
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*/
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int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
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int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
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/*-----------------------------------------------------------------
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* Functions for manipulating device-mapper tables.
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*---------------------------------------------------------------*/
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/*
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* First create an empty table.
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*/
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int dm_table_create(struct dm_table **result, fmode_t mode,
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unsigned num_targets, struct mapped_device *md);
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/*
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* Then call this once for each target.
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*/
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int dm_table_add_target(struct dm_table *t, const char *type,
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sector_t start, sector_t len, char *params);
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/*
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* Target_ctr should call this if it needs to add any callbacks.
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*/
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void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
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/*
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* Finally call this to make the table ready for use.
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*/
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int dm_table_complete(struct dm_table *t);
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/*
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* Target may require that it is never sent I/O larger than len.
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*/
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int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
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/*
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* Table reference counting.
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*/
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struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
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void dm_put_live_table(struct mapped_device *md, int srcu_idx);
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void dm_sync_table(struct mapped_device *md);
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/*
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* Queries
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*/
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sector_t dm_table_get_size(struct dm_table *t);
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unsigned int dm_table_get_num_targets(struct dm_table *t);
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fmode_t dm_table_get_mode(struct dm_table *t);
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struct mapped_device *dm_table_get_md(struct dm_table *t);
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/*
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* Trigger an event.
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*/
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void dm_table_event(struct dm_table *t);
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/*
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* Run the queue for request-based targets.
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*/
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void dm_table_run_md_queue_async(struct dm_table *t);
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/*
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* The device must be suspended before calling this method.
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* Returns the previous table, which the caller must destroy.
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*/
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struct dm_table *dm_swap_table(struct mapped_device *md,
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struct dm_table *t);
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/*
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* A wrapper around vmalloc.
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*/
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void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
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/*-----------------------------------------------------------------
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* Macros.
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*---------------------------------------------------------------*/
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#define DM_NAME "device-mapper"
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#ifdef CONFIG_PRINTK
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extern struct ratelimit_state dm_ratelimit_state;
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#define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
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#else
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#define dm_ratelimit() 0
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#endif
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#define DMCRIT(f, arg...) \
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printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
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#define DMERR(f, arg...) \
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printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
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#define DMERR_LIMIT(f, arg...) \
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do { \
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if (dm_ratelimit()) \
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printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
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f "\n", ## arg); \
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} while (0)
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#define DMWARN(f, arg...) \
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printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
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#define DMWARN_LIMIT(f, arg...) \
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do { \
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if (dm_ratelimit()) \
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printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
|
|
f "\n", ## arg); \
|
|
} while (0)
|
|
|
|
#define DMINFO(f, arg...) \
|
|
printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
|
|
#define DMINFO_LIMIT(f, arg...) \
|
|
do { \
|
|
if (dm_ratelimit()) \
|
|
printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
|
|
"\n", ## arg); \
|
|
} while (0)
|
|
|
|
#ifdef CONFIG_DM_DEBUG
|
|
# define DMDEBUG(f, arg...) \
|
|
printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
|
|
# define DMDEBUG_LIMIT(f, arg...) \
|
|
do { \
|
|
if (dm_ratelimit()) \
|
|
printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
|
|
"\n", ## arg); \
|
|
} while (0)
|
|
#else
|
|
# define DMDEBUG(f, arg...) do {} while (0)
|
|
# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
|
|
#endif
|
|
|
|
#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
|
|
0 : scnprintf(result + sz, maxlen - sz, x))
|
|
|
|
#define SECTOR_SHIFT 9
|
|
|
|
/*
|
|
* Definitions of return values from target end_io function.
|
|
*/
|
|
#define DM_ENDIO_INCOMPLETE 1
|
|
#define DM_ENDIO_REQUEUE 2
|
|
|
|
/*
|
|
* 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_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))
|
|
|
|
#define dm_array_too_big(fixed, obj, num) \
|
|
((num) > (UINT_MAX - (fixed)) / (obj))
|
|
|
|
/*
|
|
* 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 n)
|
|
{
|
|
return (n >> SECTOR_SHIFT);
|
|
}
|
|
|
|
static inline unsigned long to_bytes(sector_t n)
|
|
{
|
|
return (n << SECTOR_SHIFT);
|
|
}
|
|
|
|
#endif /* _LINUX_DEVICE_MAPPER_H */
|