linux/include/linux/blk_types.h
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   1/*
   2 * Block data types and constants.  Directly include this file only to
   3 * break include dependency loop.
   4 */
   5#ifndef __LINUX_BLK_TYPES_H
   6#define __LINUX_BLK_TYPES_H
   7
   8#ifdef CONFIG_BLOCK
   9
  10#include <linux/types.h>
  11
  12struct bio_set;
  13struct bio;
  14struct bio_integrity_payload;
  15struct page;
  16struct block_device;
  17struct io_context;
  18struct cgroup_subsys_state;
  19typedef void (bio_end_io_t) (struct bio *, int);
  20typedef void (bio_destructor_t) (struct bio *);
  21
  22/*
  23 * was unsigned short, but we might as well be ready for > 64kB I/O pages
  24 */
  25struct bio_vec {
  26        struct page     *bv_page;
  27        unsigned int    bv_len;
  28        unsigned int    bv_offset;
  29};
  30
  31/*
  32 * main unit of I/O for the block layer and lower layers (ie drivers and
  33 * stacking drivers)
  34 */
  35struct bio {
  36        sector_t                bi_sector;      /* device address in 512 byte
  37                                                   sectors */
  38        struct bio              *bi_next;       /* request queue link */
  39        struct block_device     *bi_bdev;
  40        unsigned long           bi_flags;       /* status, command, etc */
  41        unsigned long           bi_rw;          /* bottom bits READ/WRITE,
  42                                                 * top bits priority
  43                                                 */
  44
  45        unsigned short          bi_vcnt;        /* how many bio_vec's */
  46        unsigned short          bi_idx;         /* current index into bvl_vec */
  47
  48        /* Number of segments in this BIO after
  49         * physical address coalescing is performed.
  50         */
  51        unsigned int            bi_phys_segments;
  52
  53        unsigned int            bi_size;        /* residual I/O count */
  54
  55        /*
  56         * To keep track of the max segment size, we account for the
  57         * sizes of the first and last mergeable segments in this bio.
  58         */
  59        unsigned int            bi_seg_front_size;
  60        unsigned int            bi_seg_back_size;
  61
  62        bio_end_io_t            *bi_end_io;
  63
  64        void                    *bi_private;
  65#ifdef CONFIG_BLK_CGROUP
  66        /*
  67         * Optional ioc and css associated with this bio.  Put on bio
  68         * release.  Read comment on top of bio_associate_current().
  69         */
  70        struct io_context       *bi_ioc;
  71        struct cgroup_subsys_state *bi_css;
  72#endif
  73#if defined(CONFIG_BLK_DEV_INTEGRITY)
  74        struct bio_integrity_payload *bi_integrity;  /* data integrity */
  75#endif
  76
  77        /*
  78         * Everything starting with bi_max_vecs will be preserved by bio_reset()
  79         */
  80
  81        unsigned int            bi_max_vecs;    /* max bvl_vecs we can hold */
  82
  83        atomic_t                bi_cnt;         /* pin count */
  84
  85        struct bio_vec          *bi_io_vec;     /* the actual vec list */
  86
  87        struct bio_set          *bi_pool;
  88
  89        /*
  90         * We can inline a number of vecs at the end of the bio, to avoid
  91         * double allocations for a small number of bio_vecs. This member
  92         * MUST obviously be kept at the very end of the bio.
  93         */
  94        struct bio_vec          bi_inline_vecs[0];
  95};
  96
  97#define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
  98
  99/*
 100 * bio flags
 101 */
 102#define BIO_UPTODATE    0       /* ok after I/O completion */
 103#define BIO_RW_BLOCK    1       /* RW_AHEAD set, and read/write would block */
 104#define BIO_EOF         2       /* out-out-bounds error */
 105#define BIO_SEG_VALID   3       /* bi_phys_segments valid */
 106#define BIO_CLONED      4       /* doesn't own data */
 107#define BIO_BOUNCED     5       /* bio is a bounce bio */
 108#define BIO_USER_MAPPED 6       /* contains user pages */
 109#define BIO_EOPNOTSUPP  7       /* not supported */
 110#define BIO_NULL_MAPPED 8       /* contains invalid user pages */
 111#define BIO_FS_INTEGRITY 9      /* fs owns integrity data, not block layer */
 112#define BIO_QUIET       10      /* Make BIO Quiet */
 113#define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */
 114
 115/*
 116 * Flags starting here get preserved by bio_reset() - this includes
 117 * BIO_POOL_IDX()
 118 */
 119#define BIO_RESET_BITS  12
 120
 121#define bio_flagged(bio, flag)  ((bio)->bi_flags & (1 << (flag)))
 122
 123/*
 124 * top 4 bits of bio flags indicate the pool this bio came from
 125 */
 126#define BIO_POOL_BITS           (4)
 127#define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 128#define BIO_POOL_OFFSET         (BITS_PER_LONG - BIO_POOL_BITS)
 129#define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 130#define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 131
 132#endif /* CONFIG_BLOCK */
 133
 134/*
 135 * Request flags.  For use in the cmd_flags field of struct request, and in
 136 * bi_rw of struct bio.  Note that some flags are only valid in either one.
 137 */
 138enum rq_flag_bits {
 139        /* common flags */
 140        __REQ_WRITE,            /* not set, read. set, write */
 141        __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 142        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 143        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 144
 145        __REQ_SYNC,             /* request is sync (sync write or read) */
 146        __REQ_META,             /* metadata io request */
 147        __REQ_PRIO,             /* boost priority in cfq */
 148        __REQ_DISCARD,          /* request to discard sectors */
 149        __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
 150        __REQ_WRITE_SAME,       /* write same block many times */
 151
 152        __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 153        __REQ_FUA,              /* forced unit access */
 154        __REQ_FLUSH,            /* request for cache flush */
 155
 156        /* bio only flags */
 157        __REQ_RAHEAD,           /* read ahead, can fail anytime */
 158        __REQ_THROTTLED,        /* This bio has already been subjected to
 159                                 * throttling rules. Don't do it again. */
 160
 161        /* request only flags */
 162        __REQ_SORTED,           /* elevator knows about this request */
 163        __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 164        __REQ_NOMERGE,          /* don't touch this for merging */
 165        __REQ_STARTED,          /* drive already may have started this one */
 166        __REQ_DONTPREP,         /* don't call prep for this one */
 167        __REQ_QUEUED,           /* uses queueing */
 168        __REQ_ELVPRIV,          /* elevator private data attached */
 169        __REQ_FAILED,           /* set if the request failed */
 170        __REQ_QUIET,            /* don't worry about errors */
 171        __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 172        __REQ_ALLOCED,          /* request came from our alloc pool */
 173        __REQ_COPY_USER,        /* contains copies of user pages */
 174        __REQ_FLUSH_SEQ,        /* request for flush sequence */
 175        __REQ_IO_STAT,          /* account I/O stat */
 176        __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 177        __REQ_KERNEL,           /* direct IO to kernel pages */
 178        __REQ_NR_BITS,          /* stops here */
 179};
 180
 181#define REQ_WRITE               (1 << __REQ_WRITE)
 182#define REQ_FAILFAST_DEV        (1 << __REQ_FAILFAST_DEV)
 183#define REQ_FAILFAST_TRANSPORT  (1 << __REQ_FAILFAST_TRANSPORT)
 184#define REQ_FAILFAST_DRIVER     (1 << __REQ_FAILFAST_DRIVER)
 185#define REQ_SYNC                (1 << __REQ_SYNC)
 186#define REQ_META                (1 << __REQ_META)
 187#define REQ_PRIO                (1 << __REQ_PRIO)
 188#define REQ_DISCARD             (1 << __REQ_DISCARD)
 189#define REQ_WRITE_SAME          (1 << __REQ_WRITE_SAME)
 190#define REQ_NOIDLE              (1 << __REQ_NOIDLE)
 191
 192#define REQ_FAILFAST_MASK \
 193        (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 194#define REQ_COMMON_MASK \
 195        (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 196         REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
 197         REQ_SECURE)
 198#define REQ_CLONE_MASK          REQ_COMMON_MASK
 199
 200/* This mask is used for both bio and request merge checking */
 201#define REQ_NOMERGE_FLAGS \
 202        (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 203
 204#define REQ_RAHEAD              (1 << __REQ_RAHEAD)
 205#define REQ_THROTTLED           (1 << __REQ_THROTTLED)
 206
 207#define REQ_SORTED              (1 << __REQ_SORTED)
 208#define REQ_SOFTBARRIER         (1 << __REQ_SOFTBARRIER)
 209#define REQ_FUA                 (1 << __REQ_FUA)
 210#define REQ_NOMERGE             (1 << __REQ_NOMERGE)
 211#define REQ_STARTED             (1 << __REQ_STARTED)
 212#define REQ_DONTPREP            (1 << __REQ_DONTPREP)
 213#define REQ_QUEUED              (1 << __REQ_QUEUED)
 214#define REQ_ELVPRIV             (1 << __REQ_ELVPRIV)
 215#define REQ_FAILED              (1 << __REQ_FAILED)
 216#define REQ_QUIET               (1 << __REQ_QUIET)
 217#define REQ_PREEMPT             (1 << __REQ_PREEMPT)
 218#define REQ_ALLOCED             (1 << __REQ_ALLOCED)
 219#define REQ_COPY_USER           (1 << __REQ_COPY_USER)
 220#define REQ_FLUSH               (1 << __REQ_FLUSH)
 221#define REQ_FLUSH_SEQ           (1 << __REQ_FLUSH_SEQ)
 222#define REQ_IO_STAT             (1 << __REQ_IO_STAT)
 223#define REQ_MIXED_MERGE         (1 << __REQ_MIXED_MERGE)
 224#define REQ_SECURE              (1 << __REQ_SECURE)
 225#define REQ_KERNEL              (1 << __REQ_KERNEL)
 226
 227#endif /* __LINUX_BLK_TYPES_H */
 228
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