include/linux/blkdev.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Portions Copyright (C) 1992 Drew Eckhardt
 */
#ifndef _LINUX_BLKDEV_H
#define _LINUX_BLKDEV_H

#include <linux/types.h>
#include <linux/blk_types.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/llist.h>
#include <linux/minmax.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <linux/wait.h>
#include <linux/bio.h>
#include <linux/gfp.h>
#include <linux/kdev_t.h>
#include <linux/rcupdate.h>
#include <linux/percpu-refcount.h>
#include <linux/blkzoned.h>
#include <linux/sched.h>
#include <linux/sbitmap.h>
#include <linux/uuid.h>
#include <linux/xarray.h>
#include <linux/file.h>

struct module;
struct request_queue;
struct elevator_queue;
struct blk_trace;
struct request;
struct sg_io_hdr;
struct blkcg_gq;
struct blk_flush_queue;
struct kiocb;
struct pr_ops;
struct rq_qos;
struct blk_queue_stats;
struct blk_stat_callback;
struct blk_crypto_profile;

extern const struct device_type disk_type;
extern const struct device_type part_type;
extern const struct class block_class;

/*
 * Maximum number of blkcg policies allowed to be registered concurrently.
 * Defined here to simplify include dependency.
 */
#define BLKCG_MAX_POLS		6

#define DISK_MAX_PARTS			256
#define DISK_NAME_LEN			32

#define PARTITION_META_INFO_VOLNAMELTH	64
/*
 * Enough for the string representation of any kind of UUID plus NULL.
 * EFI UUID is 36 characters. MSDOS UUID is 11 characters.
 */
#define PARTITION_META_INFO_UUIDLTH	(UUID_STRING_LEN + 1)

struct partition_meta_info {
	char uuid[PARTITION_META_INFO_UUIDLTH];
	u8 volname[PARTITION_META_INFO_VOLNAMELTH];
};

/**
 * DOC: genhd capability flags
 *
 * ``GENHD_FL_REMOVABLE``: indicates that the block device gives access to
 * removable media.  When set, the device remains present even when media is not
 * inserted.  Shall not be set for devices which are removed entirely when the
 * media is removed.
 *
 * ``GENHD_FL_HIDDEN``: the block device is hidden; it doesn't produce events,
 * doesn't appear in sysfs, and can't be opened from userspace or using
 * blkdev_get*. Used for the underlying components of multipath devices.
 *
 * ``GENHD_FL_NO_PART``: partition support is disabled.  The kernel will not
 * scan for partitions from add_disk, and users can't add partitions manually.
 *
 */
enum {
	GENHD_FL_REMOVABLE			= 1 << 0,
	GENHD_FL_HIDDEN				= 1 << 1,
	GENHD_FL_NO_PART			= 1 << 2,
};

enum {
	DISK_EVENT_MEDIA_CHANGE			= 1 << 0, /* media changed */
	DISK_EVENT_EJECT_REQUEST		= 1 << 1, /* eject requested */
};

enum {
	/* Poll even if events_poll_msecs is unset */
	DISK_EVENT_FLAG_POLL			= 1 << 0,
	/* Forward events to udev */
	DISK_EVENT_FLAG_UEVENT			= 1 << 1,
	/* Block event polling when open for exclusive write */
	DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE	= 1 << 2,
};

struct disk_events;
struct badblocks;

enum blk_integrity_checksum {
	BLK_INTEGRITY_CSUM_NONE		= 0,
	BLK_INTEGRITY_CSUM_IP		= 1,
	BLK_INTEGRITY_CSUM_CRC		= 2,
	BLK_INTEGRITY_CSUM_CRC64	= 3,
} __packed ;

struct blk_integrity {
	unsigned char				flags;
	enum blk_integrity_checksum		csum_type;
	unsigned char				tuple_size;
	unsigned char				pi_offset;
	unsigned char				interval_exp;
	unsigned char				tag_size;
};

typedef unsigned int __bitwise blk_mode_t;

/* open for reading */
#define BLK_OPEN_READ		((__force blk_mode_t)(1 << 0))
/* open for writing */
#define BLK_OPEN_WRITE		((__force blk_mode_t)(1 << 1))
/* open exclusively (vs other exclusive openers */
#define BLK_OPEN_EXCL		((__force blk_mode_t)(1 << 2))
/* opened with O_NDELAY */
#define BLK_OPEN_NDELAY		((__force blk_mode_t)(1 << 3))
/* open for "writes" only for ioctls (specialy hack for floppy.c) */
#define BLK_OPEN_WRITE_IOCTL	((__force blk_mode_t)(1 << 4))
/* open is exclusive wrt all other BLK_OPEN_WRITE opens to the device */
#define BLK_OPEN_RESTRICT_WRITES	((__force blk_mode_t)(1 << 5))
/* return partition scanning errors */
#define BLK_OPEN_STRICT_SCAN	((__force blk_mode_t)(1 << 6))

struct gendisk {
	/*
	 * major/first_minor/minors should not be set by any new driver, the
	 * block core will take care of allocating them automatically.
	 */
	int major;
	int first_minor;
	int minors;

	char disk_name[DISK_NAME_LEN];	/* name of major driver */

	unsigned short events;		/* supported events */
	unsigned short event_flags;	/* flags related to event processing */

	struct xarray part_tbl;
	struct block_device *part0;

	const struct block_device_operations *fops;
	struct request_queue *queue;
	void *private_data;

	struct bio_set bio_split;

	int flags;
	unsigned long state;
#define GD_NEED_PART_SCAN		0
#define GD_READ_ONLY			1
#define GD_DEAD				2
#define GD_NATIVE_CAPACITY		3
#define GD_ADDED			4
#define GD_SUPPRESS_PART_SCAN		5
#define GD_OWNS_QUEUE			6

	struct mutex open_mutex;	/* open/close mutex */
	unsigned open_partitions;	/* number of open partitions */

	struct backing_dev_info	*bdi;
	struct kobject queue_kobj;	/* the queue/ directory */
	struct kobject *slave_dir;
#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
	struct list_head slave_bdevs;
#endif
	struct timer_rand_state *random;
	atomic_t sync_io;		/* RAID */
	struct disk_events *ev;

#ifdef CONFIG_BLK_DEV_ZONED
	/*
	 * Zoned block device information. Reads of this information must be
	 * protected with blk_queue_enter() / blk_queue_exit(). Modifying this
	 * information is only allowed while no requests are being processed.
	 * See also blk_mq_freeze_queue() and blk_mq_unfreeze_queue().
	 */
	unsigned int		nr_zones;
	unsigned int		zone_capacity;
	unsigned int		last_zone_capacity;
	unsigned long		*conv_zones_bitmap;
	unsigned int            zone_wplugs_hash_bits;
	spinlock_t              zone_wplugs_lock;
	struct mempool_s	*zone_wplugs_pool;
	struct hlist_head       *zone_wplugs_hash;
	struct list_head        zone_wplugs_err_list;
	struct work_struct	zone_wplugs_work;
	struct workqueue_struct *zone_wplugs_wq;
#endif /* CONFIG_BLK_DEV_ZONED */

#if IS_ENABLED(CONFIG_CDROM)
	struct cdrom_device_info *cdi;
#endif
	int node_id;
	struct badblocks *bb;
	struct lockdep_map lockdep_map;
	u64 diskseq;
	blk_mode_t open_mode;

	/*
	 * Independent sector access ranges. This is always NULL for
	 * devices that do not have multiple independent access ranges.
	 */
	struct blk_independent_access_ranges *ia_ranges;
};

/**
 * disk_openers - returns how many openers are there for a disk
 * @disk: disk to check
 *
 * This returns the number of openers for a disk.  Note that this value is only
 * stable if disk->open_mutex is held.
 *
 * Note: Due to a quirk in the block layer open code, each open partition is
 * only counted once even if there are multiple openers.
 */
static inline unsigned int disk_openers(struct gendisk *disk)
{
	return atomic_read(&disk->part0->bd_openers);
}

/**
 * disk_has_partscan - return %true if partition scanning is enabled on a disk
 * @disk: disk to check
 *
 * Returns %true if partitions scanning is enabled for @disk, or %false if
 * partition scanning is disabled either permanently or temporarily.
 */
static inline bool disk_has_partscan(struct gendisk *disk)
{
	return !(disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN)) &&
		!test_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
}

/*
 * The gendisk is refcounted by the part0 block_device, and the bd_device
 * therein is also used for device model presentation in sysfs.
 */
#define dev_to_disk(device) \
	(dev_to_bdev(device)->bd_disk)
#define disk_to_dev(disk) \
	(&((disk)->part0->bd_device))

#if IS_REACHABLE(CONFIG_CDROM)
#define disk_to_cdi(disk)	((disk)->cdi)
#else
#define disk_to_cdi(disk)	NULL
#endif

static inline dev_t disk_devt(struct gendisk *disk)
{
	return MKDEV(disk->major, disk->first_minor);
}

static inline int blk_validate_block_size(unsigned long bsize)
{
	if (bsize < 512 || bsize > PAGE_SIZE || !is_power_of_2(bsize))
		return -EINVAL;

	return 0;
}

static inline bool blk_op_is_passthrough(blk_opf_t op)
{
	op &= REQ_OP_MASK;
	return op == REQ_OP_DRV_IN || op == REQ_OP_DRV_OUT;
}

/*
 * BLK_BOUNCE_NONE:	never bounce (default)
 * BLK_BOUNCE_HIGH:	bounce all highmem pages
 */
enum blk_bounce {
	BLK_BOUNCE_NONE,
	BLK_BOUNCE_HIGH,
};

struct queue_limits {
	enum blk_bounce		bounce;
	unsigned long		seg_boundary_mask;
	unsigned long		virt_boundary_mask;

	unsigned int		max_hw_sectors;
	unsigned int		max_dev_sectors;
	unsigned int		chunk_sectors;
	unsigned int		max_sectors;
	unsigned int		max_user_sectors;
	unsigned int		max_segment_size;
	unsigned int		physical_block_size;
	unsigned int		logical_block_size;
	unsigned int		alignment_offset;
	unsigned int		io_min;
	unsigned int		io_opt;
	unsigned int		max_discard_sectors;
	unsigned int		max_hw_discard_sectors;
	unsigned int		max_user_discard_sectors;
	unsigned int		max_secure_erase_sectors;
	unsigned int		max_write_zeroes_sectors;
	unsigned int		max_zone_append_sectors;
	unsigned int		discard_granularity;
	unsigned int		discard_alignment;
	unsigned int		zone_write_granularity;

	unsigned short		max_segments;
	unsigned short		max_integrity_segments;
	unsigned short		max_discard_segments;

	unsigned char		misaligned;
	unsigned char		discard_misaligned;
	unsigned char		raid_partial_stripes_expensive;
	bool			zoned;
	unsigned int		max_open_zones;
	unsigned int		max_active_zones;

	/*
	 * Drivers that set dma_alignment to less than 511 must be prepared to
	 * handle individual bvec's that are not a multiple of a SECTOR_SIZE
	 * due to possible offsets.
	 */
	unsigned int		dma_alignment;

	struct blk_integrity	integrity;
};

typedef int (*report_zones_cb)(struct blk_zone *zone, unsigned int idx,
			       void *data);

#define BLK_ALL_ZONES  ((unsigned int)-1)
int blkdev_report_zones(struct block_device *bdev, sector_t sector,
		unsigned int nr_zones, report_zones_cb cb, void *data);
int blkdev_zone_mgmt(struct block_device *bdev, enum req_op op,
		sector_t sectors, sector_t nr_sectors);
int blk_revalidate_disk_zones(struct gendisk *disk);

/*
 * Independent access ranges: struct blk_independent_access_range describes
 * a range of contiguous sectors that can be accessed using device command
 * execution resources that are independent from the resources used for
 * other access ranges. This is typically found with single-LUN multi-actuator
 * HDDs where each access range is served by a different set of heads.
 * The set of independent ranges supported by the device is defined using
 * struct blk_independent_access_ranges. The independent ranges must not overlap
 * and must include all sectors within the disk capacity (no sector holes
 * allowed).
 * For a device with multiple ranges, requests targeting sectors in different
 * ranges can be executed in parallel. A request can straddle an access range
 * boundary.
 */
struct blk_independent_access_range {
	struct kobject		kobj;
	sector_t		sector;
	sector_t		nr_sectors;
};

struct blk_independent_access_ranges {
	struct kobject				kobj;
	bool					sysfs_registered;
	unsigned int				nr_ia_ranges;
	struct blk_independent_access_range	ia_range[];
};

struct request_queue {
	/*
	 * The queue owner gets to use this for whatever they like.
	 * ll_rw_blk doesn't touch it.
	 */
	void			*queuedata;

	struct elevator_queue	*elevator;

	const struct blk_mq_ops	*mq_ops;

	/* sw queues */
	struct blk_mq_ctx __percpu	*queue_ctx;

	/*
	 * various queue flags, see QUEUE_* below
	 */
	unsigned long		queue_flags;

	unsigned int		rq_timeout;

	unsigned int		queue_depth;

	refcount_t		refs;

	/* hw dispatch queues */
	unsigned int		nr_hw_queues;
	struct xarray		hctx_table;

	struct percpu_ref	q_usage_counter;

	struct request		*last_merge;

	spinlock_t		queue_lock;

	int			quiesce_depth;

	struct gendisk		*disk;

	/*
	 * mq queue kobject
	 */
	struct kobject *mq_kobj;

	struct queue_limits	limits;

#ifdef CONFIG_PM
	struct device		*dev;
	enum rpm_status		rpm_status;
#endif

	/*
	 * Number of contexts that have called blk_set_pm_only(). If this
	 * counter is above zero then only RQF_PM requests are processed.
	 */
	atomic_t		pm_only;

	struct blk_queue_stats	*stats;
	struct rq_qos		*rq_qos;
	struct mutex		rq_qos_mutex;

	/*
	 * ida allocated id for this queue.  Used to index queues from
	 * ioctx.
	 */
	int			id;

	unsigned int		dma_pad_mask;

	/*
	 * queue settings
	 */
	unsigned long		nr_requests;	/* Max # of requests */

#ifdef CONFIG_BLK_INLINE_ENCRYPTION
	struct blk_crypto_profile *crypto_profile;
	struct kobject *crypto_kobject;
#endif

	struct timer_list	timeout;
	struct work_struct	timeout_work;

	atomic_t		nr_active_requests_shared_tags;

	struct blk_mq_tags	*sched_shared_tags;

	struct list_head	icq_list;
#ifdef CONFIG_BLK_CGROUP
	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);
	struct blkcg_gq		*root_blkg;
	struct list_head	blkg_list;
	struct mutex		blkcg_mutex;
#endif

	int			node;

	spinlock_t		requeue_lock;
	struct list_head	requeue_list;
	struct delayed_work	requeue_work;

#ifdef CONFIG_BLK_DEV_IO_TRACE
	struct blk_trace __rcu	*blk_trace;
#endif
	/*
	 * for flush operations
	 */
	struct blk_flush_queue	*fq;
	struct list_head	flush_list;

	struct mutex		sysfs_lock;
	struct mutex		sysfs_dir_lock;
	struct mutex		limits_lock;

	/*
	 * for reusing dead hctx instance in case of updating
	 * nr_hw_queues
	 */
	struct list_head	unused_hctx_list;
	spinlock_t		unused_hctx_lock;

	int			mq_freeze_depth;

#ifdef CONFIG_BLK_DEV_THROTTLING
	/* Throttle data */
	struct throtl_data *td;
#endif
	struct rcu_head		rcu_head;
	wait_queue_head_t	mq_freeze_wq;
	/*
	 * Protect concurrent access to q_usage_counter by
	 * percpu_ref_kill() and percpu_ref_reinit().
	 */
	struct mutex		mq_freeze_lock;

	struct blk_mq_tag_set	*tag_set;
	struct list_head	tag_set_list;

	struct dentry		*debugfs_dir;
	struct dentry		*sched_debugfs_dir;
	struct dentry		*rqos_debugfs_dir;
	/*
	 * Serializes all debugfs metadata operations using the above dentries.
	 */
	struct mutex		debugfs_mutex;

	bool			mq_sysfs_init_done;
};

/* Keep blk_queue_flag_name[] in sync with the definitions below */
#define QUEUE_FLAG_STOPPED	0	/* queue is stopped */
#define QUEUE_FLAG_DYING	1	/* queue being torn down */
#define QUEUE_FLAG_NOMERGES     3	/* disable merge attempts */
#define QUEUE_FLAG_SAME_COMP	4	/* complete on same CPU-group */
#define QUEUE_FLAG_FAIL_IO	5	/* fake timeout */
#define QUEUE_FLAG_NONROT	6	/* non-rotational device (SSD) */
#define QUEUE_FLAG_VIRT		QUEUE_FLAG_NONROT /* paravirt device */
#define QUEUE_FLAG_IO_STAT	7	/* do disk/partitions IO accounting */
#define QUEUE_FLAG_NOXMERGES	9	/* No extended merges */
#define QUEUE_FLAG_ADD_RANDOM	10	/* Contributes to random pool */
#define QUEUE_FLAG_SYNCHRONOUS	11	/* always completes in submit context */
#define QUEUE_FLAG_SAME_FORCE	12	/* force complete on same CPU */
#define QUEUE_FLAG_HW_WC	13	/* Write back caching supported */
#define QUEUE_FLAG_INIT_DONE	14	/* queue is initialized */
#define QUEUE_FLAG_STABLE_WRITES 15	/* don't modify blks until WB is done */
#define QUEUE_FLAG_POLL		16	/* IO polling enabled if set */
#define QUEUE_FLAG_WC		17	/* Write back caching */
#define QUEUE_FLAG_FUA		18	/* device supports FUA writes */
#define QUEUE_FLAG_DAX		19	/* device supports DAX */
#define QUEUE_FLAG_STATS	20	/* track IO start and completion times */
#define QUEUE_FLAG_REGISTERED	22	/* queue has been registered to a disk */
#define QUEUE_FLAG_QUIESCED	24	/* queue has been quiesced */
#define QUEUE_FLAG_PCI_P2PDMA	25	/* device supports PCI p2p requests */
#define QUEUE_FLAG_ZONE_RESETALL 26	/* supports Zone Reset All */
#define QUEUE_FLAG_RQ_ALLOC_TIME 27	/* record rq->alloc_time_ns */
#define QUEUE_FLAG_HCTX_ACTIVE	28	/* at least one blk-mq hctx is active */
#define QUEUE_FLAG_NOWAIT       29	/* device supports NOWAIT */
#define QUEUE_FLAG_SQ_SCHED     30	/* single queue style io dispatch */
#define QUEUE_FLAG_SKIP_TAGSET_QUIESCE	31 /* quiesce_tagset skip the queue*/

#define QUEUE_FLAG_MQ_DEFAULT	((1UL << QUEUE_FLAG_IO_STAT) |		\
				 (1UL << QUEUE_FLAG_SAME_COMP) |	\
				 (1UL << QUEUE_FLAG_NOWAIT))

void blk_queue_flag_set(unsigned int flag, struct request_queue *q);
void blk_queue_flag_clear(unsigned int flag, struct request_queue *q);
bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);

#define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
#define blk_queue_dying(q)	test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
#define blk_queue_init_done(q)	test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
#define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
#define blk_queue_noxmerges(q)	\
	test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
#define blk_queue_nonrot(q)	test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
#define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
#define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
#define blk_queue_zone_resetall(q)	\
	test_bit(QUEUE_FLAG_ZONE_RESETALL, &(q)->queue_flags)
#define blk_queue_dax(q)	test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
#define blk_queue_pci_p2pdma(q)	\
	test_bit(QUEUE_FLAG_PCI_P2PDMA, &(q)->queue_flags)
#ifdef CONFIG_BLK_RQ_ALLOC_TIME
#define blk_queue_rq_alloc_time(q)	\
	test_bit(QUEUE_FLAG_RQ_ALLOC_TIME, &(q)->queue_flags)
#else
#define blk_queue_rq_alloc_time(q)	false
#endif

#define blk_noretry_request(rq) \
	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
			     REQ_FAILFAST_DRIVER))
#define blk_queue_quiesced(q)	test_bit(QUEUE_FLAG_QUIESCED, &(q)->queue_flags)
#define blk_queue_pm_only(q)	atomic_read(&(q)->pm_only)
#define blk_queue_registered(q)	test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
#define blk_queue_sq_sched(q)	test_bit(QUEUE_FLAG_SQ_SCHED, &(q)->queue_flags)
#define blk_queue_skip_tagset_quiesce(q) \
	test_bit(QUEUE_FLAG_SKIP_TAGSET_QUIESCE, &(q)->queue_flags)

extern void blk_set_pm_only(struct request_queue *q);
extern void blk_clear_pm_only(struct request_queue *q);

#define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)

#define dma_map_bvec(dev, bv, dir, attrs) \
	dma_map_page_attrs(dev, (bv)->bv_page, (bv)->bv_offset, (bv)->bv_len, \
	(dir), (attrs))

static inline bool queue_is_mq(struct request_queue *q)
{
	return q->mq_ops;
}

#ifdef CONFIG_PM
static inline enum rpm_status queue_rpm_status(struct request_queue *q)
{
	return q->rpm_status;
}
#else
static inline enum rpm_status queue_rpm_status(struct request_queue *q)
{
	return RPM_ACTIVE;
}
#endif

static inline bool blk_queue_is_zoned(struct request_queue *q)
{
	return IS_ENABLED(CONFIG_BLK_DEV_ZONED) && q->limits.zoned;
}

#ifdef CONFIG_BLK_DEV_ZONED
unsigned int bdev_nr_zones(struct block_device *bdev);

static inline unsigned int disk_nr_zones(struct gendisk *disk)
{
	return blk_queue_is_zoned(disk->queue) ? disk->nr_zones : 0;
}

static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
{
	if (!blk_queue_is_zoned(disk->queue))
		return 0;
	return sector >> ilog2(disk->queue->limits.chunk_sectors);
}

static inline unsigned int bdev_max_open_zones(struct block_device *bdev)
{
	return bdev->bd_disk->queue->limits.max_open_zones;
}

static inline unsigned int bdev_max_active_zones(struct block_device *bdev)
{
	return bdev->bd_disk->queue->limits.max_active_zones;
}

bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs);
#else /* CONFIG_BLK_DEV_ZONED */
static inline unsigned int bdev_nr_zones(struct block_device *bdev)
{
	return 0;
}

static inline unsigned int disk_nr_zones(struct gendisk *disk)
{
	return 0;
}
static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
{
	return 0;
}
static inline unsigned int bdev_max_open_zones(struct block_device *bdev)
{
	return 0;
}

static inline unsigned int bdev_max_active_zones(struct block_device *bdev)
{
	return 0;
}
static inline bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs)
{
	return false;
}
#endif /* CONFIG_BLK_DEV_ZONED */

static inline unsigned int blk_queue_depth(struct request_queue *q)
{
	if (q->queue_depth)
		return q->queue_depth;

	return q->nr_requests;
}

/*
 * default timeout for SG_IO if none specified
 */
#define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
#define BLK_MIN_SG_TIMEOUT	(7 * HZ)

/* This should not be used directly - use rq_for_each_segment */
#define for_each_bio(_bio)		\
	for (; _bio; _bio = _bio->bi_next)

int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
				 const struct attribute_group **groups);
static inline int __must_check add_disk(struct gendisk *disk)
{
	return device_add_disk(NULL, disk, NULL);
}
void del_gendisk(struct gendisk *gp);
void invalidate_disk(struct gendisk *disk);
void set_disk_ro(struct gendisk *disk, bool read_only);
void disk_uevent(struct gendisk *disk, enum kobject_action action);

static inline u8 bdev_partno(const struct block_device *bdev)
{
	return atomic_read(&bdev->__bd_flags) & BD_PARTNO;
}

static inline bool bdev_test_flag(const struct block_device *bdev, unsigned flag)
{
	return atomic_read(&bdev->__bd_flags) & flag;
}

static inline void bdev_set_flag(struct block_device *bdev, unsigned flag)
{
	atomic_or(flag, &bdev->__bd_flags);
}

static inline void bdev_clear_flag(struct block_device *bdev, unsigned flag)
{
	atomic_andnot(flag, &bdev->__bd_flags);
}

static inline int get_disk_ro(struct gendisk *disk)
{
	return bdev_test_flag(disk->part0, BD_READ_ONLY) ||
		test_bit(GD_READ_ONLY, &disk->state);
}

static inline int bdev_read_only(struct block_device *bdev)
{
	return bdev_test_flag(bdev, BD_READ_ONLY) || get_disk_ro(bdev->bd_disk);
}

bool set_capacity_and_notify(struct gendisk *disk, sector_t size);
void disk_force_media_change(struct gendisk *disk);
void bdev_mark_dead(struct block_device *bdev, bool surprise);

void add_disk_randomness(struct gendisk *disk) __latent_entropy;
void rand_initialize_disk(struct gendisk *disk);

static inline sector_t get_start_sect(struct block_device *bdev)
{
	return bdev->bd_start_sect;
}

static inline sector_t bdev_nr_sectors(struct block_device *bdev)
{
	return bdev->bd_nr_sectors;
}

static inline loff_t bdev_nr_bytes(struct block_device *bdev)
{
	return (loff_t)bdev_nr_sectors(bdev) << SECTOR_SHIFT;
}

static inline sector_t get_capacity(struct gendisk *disk)
{
	return bdev_nr_sectors(disk->part0);
}

static inline u64 sb_bdev_nr_blocks(struct super_block *sb)
{
	return bdev_nr_sectors(sb->s_bdev) >>
		(sb->s_blocksize_bits - SECTOR_SHIFT);
}

int bdev_disk_changed(struct gendisk *disk, bool invalidate);

void put_disk(struct gendisk *disk);
struct gendisk *__blk_alloc_disk(struct queue_limits *lim, int node,
		struct lock_class_key *lkclass);

/**
 * blk_alloc_disk - allocate a gendisk structure
 * @lim: queue limits to be used for this disk.
 * @node_id: numa node to allocate on
 *
 * Allocate and pre-initialize a gendisk structure for use with BIO based
 * drivers.
 *
 * Returns an ERR_PTR on error, else the allocated disk.
 *
 * Context: can sleep
 */
#define blk_alloc_disk(lim, node_id)					\
({									\
	static struct lock_class_key __key;				\
									\
	__blk_alloc_disk(lim, node_id, &__key);				\
})

int __register_blkdev(unsigned int major, const char *name,
		void (*probe)(dev_t devt));
#define register_blkdev(major, name) \
	__register_blkdev(major, name, NULL)
void unregister_blkdev(unsigned int major, const char *name);

bool disk_check_media_change(struct gendisk *disk);
void set_capacity(struct gendisk *disk, sector_t size);

#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
#else
static inline int bd_link_disk_holder(struct block_device *bdev,
				      struct gendisk *disk)
{
	return 0;
}
static inline void bd_unlink_disk_holder(struct block_device *bdev,
					 struct gendisk *disk)
{
}
#endif /* CONFIG_BLOCK_HOLDER_DEPRECATED */

dev_t part_devt(struct gendisk *disk, u8 partno);
void inc_diskseq(struct gendisk *disk);
void blk_request_module(dev_t devt);

extern int blk_register_queue(struct gendisk *disk);
extern void blk_unregister_queue(struct gendisk *disk);
void submit_bio_noacct(struct bio *bio);
struct bio *bio_split_to_limits(struct bio *bio);

extern int blk_lld_busy(struct request_queue *q);
extern int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags);
extern void blk_queue_exit(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q);

/* Helper to convert REQ_OP_XXX to its string format XXX */
extern const char *blk_op_str(enum req_op op);

int blk_status_to_errno(blk_status_t status);
blk_status_t errno_to_blk_status(int errno);
const char *blk_status_to_str(blk_status_t status);

/* only poll the hardware once, don't continue until a completion was found */
#define BLK_POLL_ONESHOT		(1 << 0)
int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags);
int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob,
			unsigned int flags);

static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
{
	return bdev->bd_queue;	/* this is never NULL */
}

/* Helper to convert BLK_ZONE_ZONE_XXX to its string format XXX */
const char *blk_zone_cond_str(enum blk_zone_cond zone_cond);

static inline unsigned int bio_zone_no(struct bio *bio)
{
	return disk_zone_no(bio->bi_bdev->bd_disk, bio->bi_iter.bi_sector);
}

static inline bool bio_straddles_zones(struct bio *bio)
{
	return bio_sectors(bio) &&
		bio_zone_no(bio) !=
		disk_zone_no(bio->bi_bdev->bd_disk, bio_end_sector(bio) - 1);
}

/*
 * Return how much of the chunk is left to be used for I/O at a given offset.
 */
static inline unsigned int blk_chunk_sectors_left(sector_t offset,
		unsigned int chunk_sectors)
{
	if (unlikely(!is_power_of_2(chunk_sectors)))
		return chunk_sectors - sector_div(offset, chunk_sectors);
	return chunk_sectors - (offset & (chunk_sectors - 1));
}

/**
 * queue_limits_start_update - start an atomic update of queue limits
 * @q:		queue to update
 *
 * This functions starts an atomic update of the queue limits.  It takes a lock
 * to prevent other updates and returns a snapshot of the current limits that
 * the caller can modify.  The caller must call queue_limits_commit_update()
 * to finish the update.
 *
 * Context: process context.  The caller must have frozen the queue or ensured
 * that there is outstanding I/O by other means.
 */
static inline struct queue_limits
queue_limits_start_update(struct request_queue *q)
	__acquires(q->limits_lock)
{
	mutex_lock(&q->limits_lock);
	return q->limits;
}
int queue_limits_commit_update(struct request_queue *q,
		struct queue_limits *lim);
int queue_limits_set(struct request_queue *q, struct queue_limits *lim);

/**
 * queue_limits_cancel_update - cancel an atomic update of queue limits
 * @q:		queue to update
 *
 * This functions cancels an atomic update of the queue limits started by
 * queue_limits_start_update() and should be used when an error occurs after
 * starting update.
 */
static inline void queue_limits_cancel_update(struct request_queue *q)
{
	mutex_unlock(&q->limits_lock);
}

/*
 * These helpers are for drivers that have sloppy feature negotiation and might
 * have to disable DISCARD, WRITE_ZEROES or SECURE_DISCARD from the I/O
 * completion handler when the device returned an indicator that the respective
 * feature is not actually supported.  They are racy and the driver needs to
 * cope with that.  Try to avoid this scheme if you can.
 */
static inline void blk_queue_disable_discard(struct request_queue *q)
{
	q->limits.max_discard_sectors = 0;
}

static inline void blk_queue_disable_secure_erase(struct request_queue *q)
{
	q->limits.max_secure_erase_sectors = 0;
}

static inline void blk_queue_disable_write_zeroes(struct request_queue *q)
{
	q->limits.max_write_zeroes_sectors = 0;
}

/*
 * Access functions for manipulating queue properties
 */
void disk_update_readahead(struct gendisk *disk);
extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth);
extern void blk_set_stacking_limits(struct queue_limits *lim);
extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
			    sector_t offset);
void queue_limits_stack_bdev(struct queue_limits *t, struct block_device *bdev,
		sector_t offset, const char *pfx);
extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fua);

struct blk_independent_access_ranges *
disk_alloc_independent_access_ranges(struct gendisk *disk, int nr_ia_ranges);
void disk_set_independent_access_ranges(struct gendisk *disk,
				struct blk_independent_access_ranges *iars);

bool __must_check blk_get_queue(struct request_queue *);
extern void blk_put_queue(struct request_queue *);

void blk_mark_disk_dead(struct gendisk *disk);

#ifdef CONFIG_BLOCK
/*
 * blk_plug permits building a queue of related requests by holding the I/O
 * fragments for a short period. This allows merging of sequential requests
 * into single larger request. As the requests are moved from a per-task list to
 * the device's request_queue in a batch, this results in improved scalability
 * as the lock contention for request_queue lock is reduced.
 *
 * It is ok not to disable preemption when adding the request to the plug list
 * or when attempting a merge. For details, please see schedule() where
 * blk_flush_plug() is called.
 */
struct blk_plug {
	struct request *mq_list; /* blk-mq requests */

	/* if ios_left is > 1, we can batch tag/rq allocations */
	struct request *cached_rq;
	u64 cur_ktime;
	unsigned short nr_ios;

	unsigned short rq_count;

	bool multiple_queues;
	bool has_elevator;

	struct list_head cb_list; /* md requires an unplug callback */
};

struct blk_plug_cb;
typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
struct blk_plug_cb {
	struct list_head list;
	blk_plug_cb_fn callback;
	void *data;
};
extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
					     void *data, int size);
extern void blk_start_plug(struct blk_plug *);
extern void blk_start_plug_nr_ios(struct blk_plug *, unsigned short);
extern void blk_finish_plug(struct blk_plug *);

void __blk_flush_plug(struct blk_plug *plug, bool from_schedule);
static inline void blk_flush_plug(struct blk_plug *plug, bool async)
{
	if (plug)
		__blk_flush_plug(plug, async);
}

/*
 * tsk == current here
 */
static inline void blk_plug_invalidate_ts(struct task_struct *tsk)
{
	struct blk_plug *plug = tsk->plug;

	if (plug)
		plug->cur_ktime = 0;
	current->flags &= ~PF_BLOCK_TS;
}

int blkdev_issue_flush(struct block_device *bdev);
long nr_blockdev_pages(void);
#else /* CONFIG_BLOCK */
struct blk_plug {
};

static inline void blk_start_plug_nr_ios(struct blk_plug *plug,
					 unsigned short nr_ios)
{
}

static inline void blk_start_plug(struct blk_plug *plug)
{
}

static inline void blk_finish_plug(struct blk_plug *plug)
{
}

static inline void blk_flush_plug(struct blk_plug *plug, bool async)
{
}

static inline void blk_plug_invalidate_ts(struct task_struct *tsk)
{
}

static inline int blkdev_issue_flush(struct block_device *bdev)
{
	return 0;
}

static inline long nr_blockdev_pages(void)
{
	return 0;
}
#endif /* CONFIG_BLOCK */

extern void blk_io_schedule(void);

int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask);
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop);
int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp);

#define BLKDEV_ZERO_NOUNMAP	(1 << 0)  /* do not free blocks */
#define BLKDEV_ZERO_NOFALLBACK	(1 << 1)  /* don't write explicit zeroes */

extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
		unsigned flags);
extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
		sector_t nr_sects, gfp_t gfp_mask, unsigned flags);

static inline int sb_issue_discard(struct super_block *sb, sector_t block,
		sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
{
	return blkdev_issue_discard(sb->s_bdev,
				    block << (sb->s_blocksize_bits -
					      SECTOR_SHIFT),
				    nr_blocks << (sb->s_blocksize_bits -
						  SECTOR_SHIFT),
				    gfp_mask);
}
static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
		sector_t nr_blocks, gfp_t gfp_mask)
{
	return blkdev_issue_zeroout(sb->s_bdev,
				    block << (sb->s_blocksize_bits -
					      SECTOR_SHIFT),
				    nr_blocks << (sb->s_blocksize_bits -
						  SECTOR_SHIFT),
				    gfp_mask, 0);
}

static inline bool bdev_is_partition(struct block_device *bdev)
{
	return bdev_partno(bdev) != 0;
}

enum blk_default_limits {
	BLK_MAX_SEGMENTS	= 128,
	BLK_SAFE_MAX_SECTORS	= 255,
	BLK_MAX_SEGMENT_SIZE	= 65536,
	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
};

/*
 * Default upper limit for the software max_sectors limit used for
 * regular file system I/O.  This can be increased through sysfs.
 *
 * Not to be confused with the max_hw_sector limit that is entirely
 * controlled by the driver, usually based on hardware limits.
 */
#define BLK_DEF_MAX_SECTORS_CAP	2560u

static inline unsigned long queue_segment_boundary(const struct request_queue *q)
{
	return q->limits.seg_boundary_mask;
}

static inline unsigned long queue_virt_boundary(const struct request_queue *q)
{
	return q->limits.virt_boundary_mask;
}

static inline unsigned int queue_max_sectors(const struct request_queue *q)
{
	return q->limits.max_sectors;
}

static inline unsigned int queue_max_bytes(struct request_queue *q)
{
	return min_t(unsigned int, queue_max_sectors(q), INT_MAX >> 9) << 9;
}

static inline unsigned int queue_max_hw_sectors(const struct request_queue *q)
{
	return q->limits.max_hw_sectors;
}

static inline unsigned short queue_max_segments(const struct request_queue *q)
{
	return q->limits.max_segments;
}

static inline unsigned short queue_max_discard_segments(const struct request_queue *q)
{
	return q->limits.max_discard_segments;
}

static inline unsigned int queue_max_segment_size(const struct request_queue *q)
{
	return q->limits.max_segment_size;
}

static inline unsigned int queue_limits_max_zone_append_sectors(struct queue_limits *l)
{
	unsigned int max_sectors = min(l->chunk_sectors, l->max_hw_sectors);

	return min_not_zero(l->max_zone_append_sectors, max_sectors);
}

static inline unsigned int queue_max_zone_append_sectors(struct request_queue *q)
{
	if (!blk_queue_is_zoned(q))
		return 0;

	return queue_limits_max_zone_append_sectors(&q->limits);
}

static inline bool queue_emulates_zone_append(struct request_queue *q)
{
	return blk_queue_is_zoned(q) && !q->limits.max_zone_append_sectors;
}

static inline bool bdev_emulates_zone_append(struct block_device *bdev)
{
	return queue_emulates_zone_append(bdev_get_queue(bdev));
}

static inline unsigned int
bdev_max_zone_append_sectors(struct block_device *bdev)
{
	return queue_max_zone_append_sectors(bdev_get_queue(bdev));
}

static inline unsigned int bdev_max_segments(struct block_device *bdev)
{
	return queue_max_segments(bdev_get_queue(bdev));
}

static inline unsigned queue_logical_block_size(const struct request_queue *q)
{
	int retval = 512;

	if (q && q->limits.logical_block_size)
		retval = q->limits.logical_block_size;

	return retval;
}

static inline unsigned int bdev_logical_block_size(struct block_device *bdev)
{
	return queue_logical_block_size(bdev_get_queue(bdev));
}

static inline unsigned int queue_physical_block_size(const struct request_queue *q)
{
	return q->limits.physical_block_size;
}

static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
{
	return queue_physical_block_size(bdev_get_queue(bdev));
}

static inline unsigned int queue_io_min(const struct request_queue *q)
{
	return q->limits.io_min;
}

static inline int bdev_io_min(struct block_device *bdev)
{
	return queue_io_min(bdev_get_queue(bdev));
}

static inline unsigned int queue_io_opt(const struct request_queue *q)
{
	return q->limits.io_opt;
}

static inline int bdev_io_opt(struct block_device *bdev)
{
	return queue_io_opt(bdev_get_queue(bdev));
}

static inline unsigned int
queue_zone_write_granularity(const struct request_queue *q)
{
	return q->limits.zone_write_granularity;
}

static inline unsigned int
bdev_zone_write_granularity(struct block_device *bdev)
{
	return queue_zone_write_granularity(bdev_get_queue(bdev));
}

int bdev_alignment_offset(struct block_device *bdev);
unsigned int bdev_discard_alignment(struct block_device *bdev);

static inline unsigned int bdev_max_discard_sectors(struct block_device *bdev)
{
	return bdev_get_queue(bdev)->limits.max_discard_sectors;
}

static inline unsigned int bdev_discard_granularity(struct block_device *bdev)
{
	return bdev_get_queue(bdev)->limits.discard_granularity;
}

static inline unsigned int
bdev_max_secure_erase_sectors(struct block_device *bdev)
{
	return bdev_get_queue(bdev)->limits.max_secure_erase_sectors;
}

static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev)
{
	struct request_queue *q = bdev_get_queue(bdev);

	if (q)
		return q->limits.max_write_zeroes_sectors;

	return 0;
}

static inline bool bdev_nonrot(struct block_device *bdev)
{
	return blk_queue_nonrot(bdev_get_queue(bdev));
}

static inline bool bdev_synchronous(struct block_device *bdev)
{
	return test_bit(QUEUE_FLAG_SYNCHRONOUS,
			&bdev_get_queue(bdev)->queue_flags);
}

static inline bool bdev_stable_writes(struct block_device *bdev)
{
	struct request_queue *q = bdev_get_queue(bdev);

	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
	    q->limits.integrity.csum_type != BLK_INTEGRITY_CSUM_NONE)
		return true;
	return test_bit(QUEUE_FLAG_STABLE_WRITES, &q->queue_flags);
}

static inline bool bdev_write_cache(struct block_device *bdev)
{
	return test_bit(QUEUE_FLAG_WC, &bdev_get_queue(bdev)->queue_flags);
}

static inline bool bdev_fua(struct block_device *bdev)
{
	return test_bit(QUEUE_FLAG_FUA, &bdev_get_queue(bdev)->queue_flags);
}

static inline bool bdev_nowait(struct block_device *bdev)
{
	return test_bit(QUEUE_FLAG_NOWAIT, &bdev_get_queue(bdev)->queue_flags);
}

static inline bool bdev_is_zoned(struct block_device *bdev)
{
	return blk_queue_is_zoned(bdev_get_queue(bdev));
}

static inline unsigned int bdev_zone_no(struct block_device *bdev, sector_t sec)
{
	return disk_zone_no(bdev->bd_disk, sec);
}

static inline sector_t bdev_zone_sectors(struct block_device *bdev)
{
	struct request_queue *q = bdev_get_queue(bdev);

	if (!blk_queue_is_zoned(q))
		return 0;
	return q->limits.chunk_sectors;
}

static inline sector_t bdev_offset_from_zone_start(struct block_device *bdev,
						   sector_t sector)
{
	return sector & (bdev_zone_sectors(bdev) - 1);
}

static inline sector_t bio_offset_from_zone_start(struct bio *bio)
{
	return bdev_offset_from_zone_start(bio->bi_bdev,
					   bio->bi_iter.bi_sector);
}

static inline bool bdev_is_zone_start(struct block_device *bdev,
				      sector_t sector)
{
	return bdev_offset_from_zone_start(bdev, sector) == 0;
}

static inline int queue_dma_alignment(const struct request_queue *q)
{
	return q ? q->limits.dma_alignment : 511;
}

static inline unsigned int bdev_dma_alignment(struct block_device *bdev)
{
	return queue_dma_alignment(bdev_get_queue(bdev));
}

static inline bool bdev_iter_is_aligned(struct block_device *bdev,
					struct iov_iter *iter)
{
	return iov_iter_is_aligned(iter, bdev_dma_alignment(bdev),
				   bdev_logical_block_size(bdev) - 1);
}

static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
				 unsigned int len)
{
	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
	return !(addr & alignment) && !(len & alignment);
}

/* assumes size > 256 */
static inline unsigned int blksize_bits(unsigned int size)
{
	return order_base_2(size >> SECTOR_SHIFT) + SECTOR_SHIFT;
}

int kblockd_schedule_work(struct work_struct *work);
int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);

#define MODULE_ALIAS_BLOCKDEV(major,minor) \
	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
	MODULE_ALIAS("block-major-" __stringify(major) "-*")

#ifdef CONFIG_BLK_INLINE_ENCRYPTION

bool blk_crypto_register(struct blk_crypto_profile *profile,
			 struct request_queue *q);

#else /* CONFIG_BLK_INLINE_ENCRYPTION */

static inline bool blk_crypto_register(struct blk_crypto_profile *profile,
				       struct request_queue *q)
{
	return true;
}

#endif /* CONFIG_BLK_INLINE_ENCRYPTION */

enum blk_unique_id {
	/* these match the Designator Types specified in SPC */
	BLK_UID_T10	= 1,
	BLK_UID_EUI64	= 2,
	BLK_UID_NAA	= 3,
};

struct block_device_operations {
	void (*submit_bio)(struct bio *bio);
	int (*poll_bio)(struct bio *bio, struct io_comp_batch *iob,
			unsigned int flags);
	int (*open)(struct gendisk *disk, blk_mode_t mode);
	void (*release)(struct gendisk *disk);
	int (*ioctl)(struct block_device *bdev, blk_mode_t mode,
			unsigned cmd, unsigned long arg);
	int (*compat_ioctl)(struct block_device *bdev, blk_mode_t mode,
			unsigned cmd, unsigned long arg);
	unsigned int (*check_events) (struct gendisk *disk,
				      unsigned int clearing);
	void (*unlock_native_capacity) (struct gendisk *);
	int (*getgeo)(struct block_device *, struct hd_geometry *);
	int (*set_read_only)(struct block_device *bdev, bool ro);
	void (*free_disk)(struct gendisk *disk);
	/* this callback is with swap_lock and sometimes page table lock held */
	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
	int (*report_zones)(struct gendisk *, sector_t sector,
			unsigned int nr_zones, report_zones_cb cb, void *data);
	char *(*devnode)(struct gendisk *disk, umode_t *mode);
	/* returns the length of the identifier or a negative errno: */
	int (*get_unique_id)(struct gendisk *disk, u8 id[16],
			enum blk_unique_id id_type);
	struct module *owner;
	const struct pr_ops *pr_ops;

	/*
	 * Special callback for probing GPT entry at a given sector.
	 * Needed by Android devices, used by GPT scanner and MMC blk
	 * driver.
	 */
	int (*alternative_gpt_sector)(struct gendisk *disk, sector_t *sector);
};

#ifdef CONFIG_COMPAT
extern int blkdev_compat_ptr_ioctl(struct block_device *, blk_mode_t,
				      unsigned int, unsigned long);
#else
#define blkdev_compat_ptr_ioctl NULL
#endif

static inline void blk_wake_io_task(struct task_struct *waiter)
{
	/*
	 * If we're polling, the task itself is doing the completions. For
	 * that case, we don't need to signal a wakeup, it's enough to just
	 * mark us as RUNNING.
	 */
	if (waiter == current)
		__set_current_state(TASK_RUNNING);
	else
		wake_up_process(waiter);
}

unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op,
				 unsigned long start_time);
void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
		      unsigned int sectors, unsigned long start_time);

unsigned long bio_start_io_acct(struct bio *bio);
void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
		struct block_device *orig_bdev);

/**
 * bio_end_io_acct - end I/O accounting for bio based drivers
 * @bio:	bio to end account for
 * @start_time:	start time returned by bio_start_io_acct()
 */
static inline void bio_end_io_acct(struct bio *bio, unsigned long start_time)
{
	return bio_end_io_acct_remapped(bio, start_time, bio->bi_bdev);
}

int bdev_read_only(struct block_device *bdev);
int set_blocksize(struct file *file, int size);

int lookup_bdev(const char *pathname, dev_t *dev);

void blkdev_show(struct seq_file *seqf, off_t offset);

#define BDEVNAME_SIZE	32	/* Largest string for a blockdev identifier */
#define BDEVT_SIZE	10	/* Largest string for MAJ:MIN for blkdev */
#ifdef CONFIG_BLOCK
#define BLKDEV_MAJOR_MAX	512
#else
#define BLKDEV_MAJOR_MAX	0
#endif

struct blk_holder_ops {
	void (*mark_dead)(struct block_device *bdev, bool surprise);

	/*
	 * Sync the file system mounted on the block device.
	 */
	void (*sync)(struct block_device *bdev);

	/*
	 * Freeze the file system mounted on the block device.
	 */
	int (*freeze)(struct block_device *bdev);

	/*
	 * Thaw the file system mounted on the block device.
	 */
	int (*thaw)(struct block_device *bdev);
};

/*
 * For filesystems using @fs_holder_ops, the @holder argument passed to
 * helpers used to open and claim block devices via
 * bd_prepare_to_claim() must point to a superblock.
 */
extern const struct blk_holder_ops fs_holder_ops;

/*
 * Return the correct open flags for blkdev_get_by_* for super block flags
 * as stored in sb->s_flags.
 */
#define sb_open_mode(flags) \
	(BLK_OPEN_READ | BLK_OPEN_RESTRICT_WRITES | \
	 (((flags) & SB_RDONLY) ? 0 : BLK_OPEN_WRITE))

struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
		const struct blk_holder_ops *hops);
struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
		void *holder, const struct blk_holder_ops *hops);
int bd_prepare_to_claim(struct block_device *bdev, void *holder,
		const struct blk_holder_ops *hops);
void bd_abort_claiming(struct block_device *bdev, void *holder);

/* just for blk-cgroup, don't use elsewhere */
struct block_device *blkdev_get_no_open(dev_t dev);
void blkdev_put_no_open(struct block_device *bdev);

struct block_device *I_BDEV(struct inode *inode);
struct block_device *file_bdev(struct file *bdev_file);
bool disk_live(struct gendisk *disk);
unsigned int block_size(struct block_device *bdev);

#ifdef CONFIG_BLOCK
void invalidate_bdev(struct block_device *bdev);
int sync_blockdev(struct block_device *bdev);
int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend);
int sync_blockdev_nowait(struct block_device *bdev);
void sync_bdevs(bool wait);
void bdev_statx_dioalign(struct inode *inode, struct kstat *stat);
void printk_all_partitions(void);
int __init early_lookup_bdev(const char *pathname, dev_t *dev);
#else
static inline void invalidate_bdev(struct block_device *bdev)
{
}
static inline int sync_blockdev(struct block_device *bdev)
{
	return 0;
}
static inline int sync_blockdev_nowait(struct block_device *bdev)
{
	return 0;
}
static inline void sync_bdevs(bool wait)
{
}
static inline void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
{
}
static inline void printk_all_partitions(void)
{
}
static inline int early_lookup_bdev(const char *pathname, dev_t *dev)
{
	return -EINVAL;
}
#endif /* CONFIG_BLOCK */

int bdev_freeze(struct block_device *bdev);
int bdev_thaw(struct block_device *bdev);
void bdev_fput(struct file *bdev_file);

struct io_comp_batch {
	struct request *req_list;
	bool need_ts;
	void (*complete)(struct io_comp_batch *);
};

#define DEFINE_IO_COMP_BATCH(name)	struct io_comp_batch name = { }

#endif /* _LINUX_BLKDEV_H */