linux/drivers/md/dm-core.h

/*
 * Internal header file _only_ for device mapper core
 *
 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the LGPL.
 */

#ifndef DM_CORE_INTERNAL_H
#define DM_CORE_INTERNAL_H

#include <linux/kthread.h>
#include <linux/ktime.h>
#include <linux/blk-mq.h>
#include <linux/blk-crypto-profile.h>
#include <linux/jump_label.h>

#include <trace/events/block.h>

#include "dm.h"
#include "dm-ima.h"

#define DM_RESERVED_MAX_IOS		1024

struct dm_io;

struct dm_kobject_holder {
	struct kobject kobj;
	struct completion completion;
};

/*
 * DM core internal structures used directly by dm.c, dm-rq.c and dm-table.c.
 * DM targets must _not_ deference a mapped_device or dm_table to directly
 * access their members!
 */

/*
 * For mempools pre-allocation at the table loading time.
 */
struct dm_md_mempools {
	struct bio_set bs;
	struct bio_set io_bs;
};

struct mapped_device {
	struct mutex suspend_lock;

	struct mutex table_devices_lock;
	struct list_head table_devices;

	/*
	 * The current mapping (struct dm_table *).
	 * Use dm_get_live_table{_fast} or take suspend_lock for
	 * dereference.
	 */
	void __rcu *map;

	unsigned long flags;

	/* Protect queue and type against concurrent access. */
	struct mutex type_lock;
	enum dm_queue_mode type;

	int numa_node_id;
	struct request_queue *queue;

	atomic_t holders;
	atomic_t open_count;

	struct dm_target *immutable_target;
	struct target_type *immutable_target_type;

	char name[16];
	struct gendisk *disk;
	struct dax_device *dax_dev;

	wait_queue_head_t wait;
	unsigned long __percpu *pending_io;

	/* forced geometry settings */
	struct hd_geometry geometry;

	/*
	 * Processing queue (flush)
	 */
	struct workqueue_struct *wq;

	/*
	 * A list of ios that arrived while we were suspended.
	 */
	struct work_struct work;
	spinlock_t deferred_lock;
	struct bio_list deferred;

	/*
	 * requeue work context is needed for cloning one new bio
	 * to represent the dm_io to be requeued, since each
	 * dm_io may point to the original bio from FS.
	 */
	struct work_struct requeue_work;
	struct dm_io *requeue_list;

	void *interface_ptr;

	/*
	 * Event handling.
	 */
	wait_queue_head_t eventq;
	atomic_t event_nr;
	atomic_t uevent_seq;
	struct list_head uevent_list;
	spinlock_t uevent_lock; /* Protect access to uevent_list */

	/* for blk-mq request-based DM support */
	bool init_tio_pdu:1;
	struct blk_mq_tag_set *tag_set;

	struct dm_stats stats;

	/* the number of internal suspends */
	unsigned internal_suspend_count;

	int swap_bios;
	struct semaphore swap_bios_semaphore;
	struct mutex swap_bios_lock;

	/*
	 * io objects are allocated from here.
	 */
	struct dm_md_mempools *mempools;

	/* kobject and completion */
	struct dm_kobject_holder kobj_holder;

	struct srcu_struct io_barrier;

#ifdef CONFIG_BLK_DEV_ZONED
	unsigned int nr_zones;
	unsigned int *zwp_offset;
#endif

#ifdef CONFIG_IMA
	struct dm_ima_measurements ima;
#endif
};

/*
 * Bits for the flags field of struct mapped_device.
 */
#define DMF_BLOCK_IO_FOR_SUSPEND 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_DEFERRED_REMOVE 6
#define DMF_SUSPENDED_INTERNALLY 7
#define DMF_POST_SUSPENDING 8
#define DMF_EMULATE_ZONE_APPEND 9

void disable_discard(struct mapped_device *md);
void disable_write_zeroes(struct mapped_device *md);

static inline sector_t dm_get_size(struct mapped_device *md)
{
	return get_capacity(md->disk);
}

static inline struct dm_stats *dm_get_stats(struct mapped_device *md)
{
	return &md->stats;
}

DECLARE_STATIC_KEY_FALSE(stats_enabled);
DECLARE_STATIC_KEY_FALSE(swap_bios_enabled);
DECLARE_STATIC_KEY_FALSE(zoned_enabled);

static inline bool dm_emulate_zone_append(struct mapped_device *md)
{
	if (blk_queue_is_zoned(md->queue))
		return test_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
	return false;
}

#define DM_TABLE_MAX_DEPTH 16

struct dm_table {
	struct mapped_device *md;
	enum dm_queue_mode type;

	/* btree table */
	unsigned int depth;
	unsigned int counts[DM_TABLE_MAX_DEPTH]; /* in nodes */
	sector_t *index[DM_TABLE_MAX_DEPTH];

	unsigned int num_targets;
	unsigned int num_allocated;
	sector_t *highs;
	struct dm_target *targets;

	struct target_type *immutable_target_type;

	bool integrity_supported:1;
	bool singleton:1;
	unsigned integrity_added:1;

	/*
	 * Indicates the rw permissions for the new logical
	 * device.  This should be a combination of FMODE_READ
	 * and FMODE_WRITE.
	 */
	fmode_t mode;

	/* a list of devices used by this table */
	struct list_head devices;

	/* events get handed up using this callback */
	void (*event_fn)(void *);
	void *event_context;

	struct dm_md_mempools *mempools;

#ifdef CONFIG_BLK_INLINE_ENCRYPTION
	struct blk_crypto_profile *crypto_profile;
#endif
};

static inline struct dm_target *dm_table_get_target(struct dm_table *t,
						    unsigned int index)
{
	BUG_ON(index >= t->num_targets);
	return t->targets + index;
}

/*
 * One of these is allocated per clone bio.
 */
#define DM_TIO_MAGIC 28714
struct dm_target_io {
	unsigned short magic;
	blk_short_t flags;
	unsigned int target_bio_nr;
	struct dm_io *io;
	struct dm_target *ti;
	unsigned int *len_ptr;
	sector_t old_sector;
	struct bio clone;
};
#define DM_TARGET_IO_BIO_OFFSET (offsetof(struct dm_target_io, clone))
#define DM_IO_BIO_OFFSET \
	(offsetof(struct dm_target_io, clone) + offsetof(struct dm_io, tio))

/*
 * dm_target_io flags
 */
enum {
	DM_TIO_INSIDE_DM_IO,
	DM_TIO_IS_DUPLICATE_BIO
};

static inline bool dm_tio_flagged(struct dm_target_io *tio, unsigned int bit)
{
	return (tio->flags & (1U << bit)) != 0;
}

static inline void dm_tio_set_flag(struct dm_target_io *tio, unsigned int bit)
{
	tio->flags |= (1U << bit);
}

static inline bool dm_tio_is_normal(struct dm_target_io *tio)
{
	return (dm_tio_flagged(tio, DM_TIO_INSIDE_DM_IO) &&
		!dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
}

/*
 * One of these is allocated per original bio.
 * It contains the first clone used for that original.
 */
#define DM_IO_MAGIC 19577
struct dm_io {
	unsigned short magic;
	blk_short_t flags;
	spinlock_t lock;
	unsigned long start_time;
	void *data;
	struct dm_io *next;
	struct dm_stats_aux stats_aux;
	blk_status_t status;
	atomic_t io_count;
	struct mapped_device *md;

	/* The three fields represent mapped part of original bio */
	struct bio *orig_bio;
	unsigned int sector_offset; /* offset to end of orig_bio */
	unsigned int sectors;

	/* last member of dm_target_io is 'struct bio' */
	struct dm_target_io tio;
};

/*
 * dm_io flags
 */
enum {
	DM_IO_ACCOUNTED,
	DM_IO_WAS_SPLIT
};

static inline bool dm_io_flagged(struct dm_io *io, unsigned int bit)
{
	return (io->flags & (1U << bit)) != 0;
}

static inline void dm_io_set_flag(struct dm_io *io, unsigned int bit)
{
	io->flags |= (1U << bit);
}

void dm_io_rewind(struct dm_io *io, struct bio_set *bs);

static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
{
	return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
}

unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);

static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
{
	return !maxlen || strlen(result) + 1 >= maxlen;
}

extern atomic_t dm_global_event_nr;
extern wait_queue_head_t dm_global_eventq;
void dm_issue_global_event(void);

#endif