path: root/include/linux/blkdev.h

#ifndef _LINUX_BLKDEV_H
#define _LINUX_BLKDEV_H

#include <linux/sched.h>

#ifdef CONFIG_BLOCK

#include <linux/major.h>
#include <linux/genhd.h>
#include <linux/list.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
#include <linux/mempool.h>
#include <linux/bio.h>
#include <linux/stringify.h>
#include <linux/gfp.h>
#include <linux/bsg.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>

#include <asm/scatterlist.h>

struct module;
struct scsi_ioctl_command;

struct request_queue;
struct elevator_queue;
struct request_pm_state;
struct blk_trace;
struct request;
struct sg_io_hdr;
struct bsg_job;
struct blkcg_gq;

#define BLKDEV_MIN_RQ	4
#define BLKDEV_MAX_RQ	128	/* Default maximum */

/*
 * Maximum number of blkcg policies allowed to be registered concurrently.
 * Defined here to simplify include dependency.
 */
#define BLKCG_MAX_POLS		2

struct request;
typedef void (rq_end_io_fn)(struct request *, int);

#define BLK_RL_SYNCFULL		(1U << 0)
#define BLK_RL_ASYNCFULL	(1U << 1)

struct request_list {
	struct request_queue	*q;	/* the queue this rl belongs to */
#ifdef CONFIG_BLK_CGROUP
	struct blkcg_gq		*blkg;	/* blkg this request pool belongs to */
#endif
	/*
	 * count[], starved[], and wait[] are indexed by
	 * BLK_RW_SYNC/BLK_RW_ASYNC
	 */
	int			count[2];
	int			starved[2];
	mempool_t		*rq_pool;
	wait_queue_head_t	wait[2];
	unsigned int		flags;
};

/*
 * request command types
 */
enum rq_cmd_type_bits {
	REQ_TYPE_FS		= 1,	/* fs request */
	REQ_TYPE_BLOCK_PC,		/* scsi command */
	REQ_TYPE_SENSE,			/* sense request */
	REQ_TYPE_PM_SUSPEND,		/* suspend request */
	REQ_TYPE_PM_RESUME,		/* resume request */
	REQ_TYPE_PM_SHUTDOWN,		/* shutdown request */
	REQ_TYPE_SPECIAL,		/* driver defined type */
	/*
	 * for ATA/ATAPI devices. this really doesn't belong here, ide should
	 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
	 * private REQ_LB opcodes to differentiate what type of request this is
	 */
	REQ_TYPE_ATA_TASKFILE,
	REQ_TYPE_ATA_PC,
};

#define BLK_MAX_CDB	16

/*
 * try to put the fields that are referenced together in the same cacheline.
 * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
 * as well!
 */
struct request {
	struct list_head queuelist;
	struct call_single_data csd;

	struct request_queue *q;

	unsigned int cmd_flags;
	enum rq_cmd_type_bits cmd_type;
	unsigned long atomic_flags;

	int cpu;

	/* the following two fields are internal, NEVER access directly */
	unsigned int __data_len;	/* total data len */
	sector_t __sector;		/* sector cursor */

	struct bio *bio;
	struct bio *biotail;

	struct hlist_node hash;	/* merge hash */
	/*
	 * The rb_node is only used inside the io scheduler, requests
	 * are pruned when moved to the dispatch queue. So let the
	 * completion_data share space with the rb_node.
	 */
	union {
		struct rb_node rb_node;	/* sort/lookup */
		void *completion_data;
	};

	/*
	 * Three pointers are available for the IO schedulers, if they need
	 * more they have to dynamically allocate it.  Flush requests are
	 * never put on the IO scheduler. So let the flush fields share
	 * space with the elevator data.
	 */
	union {
		struct {
			struct io_cq		*icq;
			void			*priv[2];
		} elv;

		struct {
			unsigned int		seq;
			struct list_head	list;
			rq_end_io_fn		*saved_end_io;
		} flush;
	};

	struct gendisk *rq_disk;
	struct hd_struct *part;
	unsigned long start_time;
#ifdef CONFIG_BLK_CGROUP
	struct request_list *rl;		/* rl this rq is alloced from */
	unsigned long long start_time_ns;
	unsigned long long io_start_time_ns;    /* when passed to hardware */
#endif
	/* Number of scatter-gather DMA addr+len pairs after
	 * physical address coalescing is performed.
	 */
	unsigned short nr_phys_segments;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
	unsigned short nr_integrity_segments;
#endif

	unsigned short ioprio;

	int ref_count;

	void *special;		/* opaque pointer available for LLD use */
	char *buffer;		/* kaddr of the current segment if available */

	int tag;
	int errors;

	/*
	 * when request is used as a packet command carrier
	 */
	unsigned char __cmd[BLK_MAX_CDB];
	unsigned char *cmd;
	unsigned short cmd_len;

	unsigned int extra_len;	/* length of alignment and padding */
	unsigned int sense_len;
	unsigned int resid_len;	/* residual count */
	void *sense;

	unsigned long deadline;
	struct list_head timeout_list;
	unsigned int timeout;
	int retries;

	/*
	 * completion callback.
	 */
	rq_end_io_fn *end_io;
	void *end_io_data;

	/* for bidi */
	struct request *next_rq;
};

static inline unsigned short req_get_ioprio(struct request *req)
{
	return req->ioprio;
}

/*
 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 * requests. Some step values could eventually be made generic.
 */
struct request_pm_state
{
	/* PM state machine step value, currently driver specific */
	int	pm_step;
	/* requested PM state value (S1, S2, S3, S4, ...) */
	u32	pm_state;
	void*	data;		/* for driver use */
};

#include <linux/elevator.h>

typedef void (request_fn_proc) (struct request_queue *q);
typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
typedef int (prep_rq_fn) (struct request_queue *, struct request *);
typedef void (unprep_rq_fn) (struct request_queue *, struct request *);

struct bio_vec;
struct bvec_merge_data {
	struct block_device *bi_bdev;
	sector_t bi_sector;
	unsigned bi_size;
	unsigned long bi_rw;
};
typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
			     struct bio_vec *);
typedef void (softirq_done_fn)(struct request *);
typedef int (dma_drain_needed_fn)(struct request *);
typedef int (lld_busy_fn) (struct request_queue *q);
typedef int (bsg_job_fn) (struct bsg_job *);

enum blk_eh_timer_return {
	BLK_EH_NOT_HANDLED,
	BLK_EH_HANDLED,
	BLK_EH_RESET_TIMER,
};

typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);

enum blk_queue_state {
	Queue_down,
	Queue_up,
};

struct blk_queue_tag {
	struct request **tag_index;	/* map of busy tags */
	unsigned long *tag_map;		/* bit map of free/busy tags */
	int busy;			/* current depth */
	int max_depth;			/* what we will send to device */
	int real_max_depth;		/* what the array can hold */
	atomic_t refcnt;		/* map can be shared */
};

#define BLK_SCSI_MAX_CMDS	(256)
#define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))

struct queue_limits {
	unsigned long		bounce_pfn;
	unsigned long		seg_boundary_mask;

	unsigned int		max_hw_sectors;
	unsigned int		max_sectors;
	unsigned int		max_segment_size;
	unsigned int		physical_block_size;
	unsigned int		alignment_offset;
	unsigned int		io_min;
	unsigned int		io_opt;
	unsigned int		max_discard_sectors;
	unsigned int		max_write_same_sectors;
	unsigned int		discard_granularity;
	unsigned int		discard_alignment;

	unsigned short		logical_block_size;
	unsigned short		max_segments;
	unsigned short		max_integrity_segment