/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Block data types and constants.  Directly include this file only to
 * break include dependency loop.
 */
#ifndef __LINUX_BLK_TYPES_H
#define __LINUX_BLK_TYPES_H

#include <linux/types.h>
#include <linux/bvec.h>

struct bio_set;
struct bio;
struct bio_integrity_payload;
struct page;
struct block_device;
struct io_context;
struct cgroup_subsys_state;
typedef void (bio_end_io_t) (struct bio *);

/*
 * Block error status values.  See block/blk-core:blk_errors for the details.
 * Alpha cannot write a byte atomically, so we need to use 32-bit value.
 */
#if defined(CONFIG_ALPHA) && !defined(__alpha_bwx__)
typedef u32 __bitwise blk_status_t;
#else
typedef u8 __bitwise blk_status_t;
#endif
#define BLK_STS_OK 0
#define BLK_STS_NOTSUPP         ((__force blk_status_t)1)
#define BLK_STS_TIMEOUT         ((__force blk_status_t)2)
#define BLK_STS_NOSPC           ((__force blk_status_t)3)
#define BLK_STS_TRANSPORT       ((__force blk_status_t)4)
#define BLK_STS_TARGET          ((__force blk_status_t)5)
#define BLK_STS_NEXUS           ((__force blk_status_t)6)
#define BLK_STS_MEDIUM          ((__force blk_status_t)7)
#define BLK_STS_PROTECTION      ((__force blk_status_t)8)
#define BLK_STS_RESOURCE        ((__force blk_status_t)9)
#define BLK_STS_IOERR           ((__force blk_status_t)10)

/* hack for device mapper, don't use elsewhere: */
#define BLK_STS_DM_REQUEUE    ((__force blk_status_t)11)

#define BLK_STS_AGAIN           ((__force blk_status_t)12)

/*
 * BLK_STS_DEV_RESOURCE is returned from the driver to the block layer if
 * device related resources are unavailable, but the driver can guarantee
 * that the queue will be rerun in the future once resources become
 * available again. This is typically the case for device specific
 * resources that are consumed for IO. If the driver fails allocating these
 * resources, we know that inflight (or pending) IO will free these
 * resource upon completion.
 *
 * This is different from BLK_STS_RESOURCE in that it explicitly references
 * a device specific resource. For resources of wider scope, allocation
 * failure can happen without having pending IO. This means that we can't
 * rely on request completions freeing these resources, as IO may not be in
 * flight. Examples of that are kernel memory allocations, DMA mappings, or
 * any other system wide resources.
 */
#define BLK_STS_DEV_RESOURCE    ((__force blk_status_t)13)

/**
 * blk_path_error - returns true if error may be path related
 * @error: status the request was completed with
 *
 * Description:
 *     This classifies block error status into non-retryable errors and ones
 *     that may be successful if retried on a failover path.
 *
 * Return:
 *     %false - retrying failover path will not help
 *     %true  - may succeed if retried
 */
static inline bool blk_path_error(blk_status_t error)
{
        switch (error) {
        case BLK_STS_NOTSUPP:
        case BLK_STS_NOSPC:
        case BLK_STS_TARGET:
        case BLK_STS_NEXUS:
        case BLK_STS_MEDIUM:
        case BLK_STS_PROTECTION:
                return false;
        }

        /* Anything else could be a path failure, so should be retried */
        return true;
}

struct blk_issue_stat {
        u64 stat;
};

/*
 * main unit of I/O for the block layer and lower layers (ie drivers and
 * stacking drivers)
 */
struct bio {
        struct bio              *bi_next;       /* request queue link */
        struct gendisk          *bi_disk;
        unsigned int            bi_opf;         /* bottom bits req flags,
                                                 * top bits REQ_OP. Use
                                                 * accessors.
                                                 */
        unsigned short          bi_flags;       /* status, etc and bvec pool number */
        unsigned short          bi_ioprio;
        unsigned short          bi_write_hint;
        blk_status_t            bi_status;
        u8                      bi_partno;

        /* Number of segments in this BIO after
         * physical address coalescing is performed.
         */
        unsigned int            bi_phys_segments;

        /*
         * To keep track of the max segment size, we account for the
         * sizes of the first and last mergeable segments in this bio.
         */
        unsigned int            bi_seg_front_size;
        unsigned int            bi_seg_back_size;

        struct bvec_iter        bi_iter;

        atomic_t                __bi_remaining;
        bio_end_io_t            *bi_end_io;

        void                    *bi_private;
#ifdef CONFIG_BLK_CGROUP
        /*
         * Optional ioc and css associated with this bio.  Put on bio
         * release.  Read comment on top of bio_associate_current().
         */
        struct io_context       *bi_ioc;
        struct cgroup_subsys_state *bi_css;
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
        void                    *bi_cg_private;
        struct blk_issue_stat   bi_issue_stat;
#endif
#endif
        union {
#if defined(CONFIG_BLK_DEV_INTEGRITY)
                struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif
        };

        unsigned short          bi_vcnt;        /* how many bio_vec's */

        /*
         * Everything starting with bi_max_vecs will be preserved by bio_reset()
         */

        unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */

        atomic_t                __bi_cnt;       /* pin count */

        struct bio_vec          *bi_io_vec;     /* the actual vec list */

        struct bio_set          *bi_pool;

        /*
         * We can inline a number of vecs at the end of the bio, to avoid
         * double allocations for a small number of bio_vecs. This member
         * MUST obviously be kept at the very end of the bio.
         */
        struct bio_vec          bi_inline_vecs[0];
};

#define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)

/*
 * bio flags
 */
#define BIO_SEG_VALID   1       /* bi_phys_segments valid */
#define BIO_CLONED      2       /* doesn't own data */
#define BIO_BOUNCED     3       /* bio is a bounce bio */
#define BIO_USER_MAPPED 4       /* contains user pages */
#define BIO_NULL_MAPPED 5       /* contains invalid user pages */
#define BIO_QUIET       6       /* Make BIO Quiet */
#define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
#define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
#define BIO_THROTTLED   9       /* This bio has already been subjected to
                                 * throttling rules. Don't do it again. */
#define BIO_TRACE_COMPLETION 10 /* bio_endio() should trace the final completion
                                 * of this bio. */
/* See BVEC_POOL_OFFSET below before adding new flags */

/*
 * We support 6 different bvec pools, the last one is magic in that it
 * is backed by a mempool.
 */
#define BVEC_POOL_NR            6
#define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)

/*
 * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
 * 1 to the actual index so that 0 indicates that there are no bvecs to be
 * freed.
 */
#define BVEC_POOL_BITS          (3)
#define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
#define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
#if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
# error "BVEC_POOL_BITS is too small"
#endif

/*
 * Flags starting here get preserved by bio_reset() - this includes
 * only BVEC_POOL_IDX()
 */
#define BIO_RESET_BITS  BVEC_POOL_OFFSET

typedef __u32 __bitwise blk_mq_req_flags_t;

/*
 * Operations and flags common to the bio and request structures.
 * We use 8 bits for encoding the operation, and the remaining 24 for flags.
 *
 * The least significant bit of the operation number indicates the data
 * transfer direction:
 *
 *   - if the least significant bit is set transfers are TO the device
 *   - if the least significant bit is not set transfers are FROM the device
 *
 * If a operation does not transfer data the least significant bit has no
 * meaning.
 */
#define REQ_OP_BITS     8
#define REQ_OP_MASK     ((1 << REQ_OP_BITS) - 1)
#define REQ_FLAG_BITS   24

enum req_opf {
        /* read sectors from the device */
        REQ_OP_READ             = 0,
        /* write sectors to the device */
        REQ_OP_WRITE            = 1,
        /* flush the volatile write cache */
        REQ_OP_FLUSH            = 2,
        /* discard sectors */
        REQ_OP_DISCARD          = 3,
        /* get zone information */
        REQ_OP_ZONE_REPORT      = 4,
        /* securely erase sectors */
        REQ_OP_SECURE_ERASE     = 5,
        /* seset a zone write pointer */
        REQ_OP_ZONE_RESET       = 6,
        /* write the same sector many times */
        REQ_OP_WRITE_SAME       = 7,
        /* write the zero filled sector many times */
        REQ_OP_WRITE_ZEROES     = 9,

        /* SCSI passthrough using struct scsi_request */
        REQ_OP_SCSI_IN          = 32,
        REQ_OP_SCSI_OUT         = 33,
        /* Driver private requests */
        REQ_OP_DRV_IN           = 34,
        REQ_OP_DRV_OUT          = 35,

        REQ_OP_LAST,
};

enum req_flag_bits {
        __REQ_FAILFAST_DEV =    /* no driver retries of device errors */
                REQ_OP_BITS,
        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
        __REQ_SYNC,             /* request is sync (sync write or read) */
        __REQ_META,             /* metadata io request */
        __REQ_PRIO,             /* boost priority in cfq */
        __REQ_NOMERGE,          /* don't touch this for merging */
        __REQ_IDLE,             /* anticipate more IO after this one */
        __REQ_INTEGRITY,        /* I/O includes block integrity payload */
        __REQ_FUA,              /* forced unit access */
        __REQ_PREFLUSH,         /* request for cache flush */
        __REQ_RAHEAD,           /* read ahead, can fail anytime */
        __REQ_BACKGROUND,       /* background IO */
        __REQ_NOWAIT,           /* Don't wait if request will block */

        /* command specific flags for REQ_OP_WRITE_ZEROES: */
        __REQ_NOUNMAP,          /* do not free blocks when zeroing */

        /* for driver use */
        __REQ_DRV,

        __REQ_NR_BITS,          /* stops here */
};

#define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
#define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
#define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
#define REQ_SYNC                (1ULL << __REQ_SYNC)
#define REQ_META                (1ULL << __REQ_META)
#define REQ_PRIO                (1ULL << __REQ_PRIO)
#define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
#define REQ_IDLE                (1ULL << __REQ_IDLE)
#define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
#define REQ_FUA                 (1ULL << __REQ_FUA)
#define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
#define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
#define REQ_BACKGROUND          (1ULL << __REQ_BACKGROUND)
#define REQ_NOWAIT              (1ULL << __REQ_NOWAIT)

#define REQ_NOUNMAP             (1ULL << __REQ_NOUNMAP)

#define REQ_DRV                 (1ULL << __REQ_DRV)

#define REQ_FAILFAST_MASK \
        (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)

#define REQ_NOMERGE_FLAGS \
        (REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)

#define bio_op(bio) \
        ((bio)->bi_opf & REQ_OP_MASK)
#define req_op(req) \
        ((req)->cmd_flags & REQ_OP_MASK)

/* obsolete, don't use in new code */
static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
                unsigned op_flags)
{
        bio->bi_opf = op | op_flags;
}

static inline bool op_is_write(unsigned int op)
{
        return (op & 1);
}

/*
 * Check if the bio or request is one that needs special treatment in the
 * flush state machine.
 */
static inline bool op_is_flush(unsigned int op)
{
        return op & (REQ_FUA | REQ_PREFLUSH);
}

/*
 * Reads are always treated as synchronous, as are requests with the FUA or
 * PREFLUSH flag.  Other operations may be marked as synchronous using the
 * REQ_SYNC flag.
 */
static inline bool op_is_sync(unsigned int op)
{
        return (op & REQ_OP_MASK) == REQ_OP_READ ||
                (op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
}

typedef unsigned int blk_qc_t;
#define BLK_QC_T_NONE           -1U
#define BLK_QC_T_SHIFT          16
#define BLK_QC_T_INTERNAL       (1U << 31)

static inline bool blk_qc_t_valid(blk_qc_t cookie)
{
        return cookie != BLK_QC_T_NONE;
}

static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
                                       bool internal)
{
        blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);

        if (internal)
                ret |= BLK_QC_T_INTERNAL;

        return ret;
}

static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
{
        return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
}

static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
{
        return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
}

static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
{
        return (cookie & BLK_QC_T_INTERNAL) != 0;
}

struct blk_rq_stat {
        u64 mean;
        u64 min;
        u64 max;
        u32 nr_samples;
        u64 batch;
};

#endif /* __LINUX_BLK_TYPES_H */