LXR linux/include/linux/blk

   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#include <linux/types.h>
   9
  10struct bio_set;
  11struct bio;
  12struct bio_integrity_payload;
  13struct page;
  14struct block_device;
  15struct io_context;
  16struct cgroup_subsys_state;
  17typedef void (bio_end_io_t) (struct bio *, int);
  18typedef void (bio_destructor_t) (struct bio *);
  19
  20/*
  21 * was unsigned short, but we might as well be ready for > 64kB I/O pages
  22 */
  23struct bio_vec {
  24        struct page     *bv_page;
  25        unsigned int    bv_len;
  26        unsigned int    bv_offset;
  27};
  28
  29#ifdef CONFIG_BLOCK
  30
  31struct bvec_iter {
  32        sector_t                bi_sector;      /* device address in 512 byte
  33                                                   sectors */
  34        unsigned int            bi_size;        /* residual I/O count */
  35
  36        unsigned int            bi_idx;         /* current index into bvl_vec */
  37
  38        unsigned int            bi_bvec_done;   /* number of bytes completed in
  39                                                   current bvec */
  40};
  41
  42/*
  43 * main unit of I/O for the block layer and lower layers (ie drivers and
  44 * stacking drivers)
  45 */
  46struct bio {
  47        struct bio              *bi_next;       /* request queue link */
  48        struct block_device     *bi_bdev;
  49        unsigned long           bi_flags;       /* status, command, etc */
  50        unsigned long           bi_rw;          /* bottom bits READ/WRITE,
  51                                                 * top bits priority
  52                                                 */
  53
  54        struct bvec_iter        bi_iter;
  55
  56        /* Number of segments in this BIO after
  57         * physical address coalescing is performed.
  58         */
  59        unsigned int            bi_phys_segments;
  60
  61        /*
  62         * To keep track of the max segment size, we account for the
  63         * sizes of the first and last mergeable segments in this bio.
  64         */
  65        unsigned int            bi_seg_front_size;
  66        unsigned int            bi_seg_back_size;
  67
  68        atomic_t                __bi_remaining;
  69
  70        bio_end_io_t            *bi_end_io;
  71
  72        void                    *bi_private;
  73#ifdef CONFIG_BLK_CGROUP
  74        /*
  75         * Optional ioc and css associated with this bio.  Put on bio
  76         * release.  Read comment on top of bio_associate_current().
  77         */
  78        struct io_context       *bi_ioc;
  79        struct cgroup_subsys_state *bi_css;
  80#endif
  81        union {
  82#if defined(CONFIG_BLK_DEV_INTEGRITY)
  83                struct bio_integrity_payload *bi_integrity; /* data integrity */
  84#endif
  85        };
  86
  87        unsigned short          bi_vcnt;        /* how many bio_vec's */
  88
  89        /*
  90         * Everything starting with bi_max_vecs will be preserved by bio_reset()
  91         */
  92
  93        unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
  94
  95        atomic_t                __bi_cnt;       /* pin count */
  96
  97        struct bio_vec          *bi_io_vec;     /* the actual vec list */
  98
  99        struct bio_set          *bi_pool;
 100
 101        /*
 102         * We can inline a number of vecs at the end of the bio, to avoid
 103         * double allocations for a small number of bio_vecs. This member
 104         * MUST obviously be kept at the very end of the bio.
 105         */
 106        struct bio_vec          bi_inline_vecs[0];
 107};
 108
 109#define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 110
 111/*
 112 * bio flags
 113 */
 114#define BIO_UPTODATE    0       /* ok after I/O completion */
 115#define BIO_SEG_VALID   1       /* bi_phys_segments valid */
 116#define BIO_CLONED      2       /* doesn't own data */
 117#define BIO_BOUNCED     3       /* bio is a bounce bio */
 118#define BIO_USER_MAPPED 4       /* contains user pages */
 119#define BIO_NULL_MAPPED 5       /* contains invalid user pages */
 120#define BIO_QUIET       6       /* Make BIO Quiet */
 121#define BIO_SNAP_STABLE 7       /* bio data must be snapshotted during write */
 122#define BIO_CHAIN       8       /* chained bio, ->bi_remaining in effect */
 123#define BIO_REFFED      9       /* bio has elevated ->bi_cnt */
 124
 125/*
 126 * Flags starting here get preserved by bio_reset() - this includes
 127 * BIO_POOL_IDX()
 128 */
 129#define BIO_RESET_BITS  13
 130#define BIO_OWNS_VEC    13      /* bio_free() should free bvec */
 131
 132#define bio_flagged(bio, flag)  ((bio)->bi_flags & (1 << (flag)))
 133
 134/*
 135 * top 4 bits of bio flags indicate the pool this bio came from
 136 */
 137#define BIO_POOL_BITS           (4)
 138#define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 139#define BIO_POOL_OFFSET         (BITS_PER_LONG - BIO_POOL_BITS)
 140#define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 141#define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 142
 143#endif /* CONFIG_BLOCK */
 144
 145/*
 146 * Request flags.  For use in the cmd_flags field of struct request, and in
 147 * bi_rw of struct bio.  Note that some flags are only valid in either one.
 148 */
 149enum rq_flag_bits {
 150        /* common flags */
 151        __REQ_WRITE,            /* not set, read. set, write */
 152        __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 153        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 154        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 155
 156        __REQ_SYNC,             /* request is sync (sync write or read) */
 157        __REQ_META,             /* metadata io request */
 158        __REQ_PRIO,             /* boost priority in cfq */
 159        __REQ_DISCARD,          /* request to discard sectors */
 160        __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
 161        __REQ_WRITE_SAME,       /* write same block many times */
 162
 163        __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 164        __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 165        __REQ_FUA,              /* forced unit access */
 166        __REQ_FLUSH,            /* request for cache flush */
 167
 168        /* bio only flags */
 169        __REQ_RAHEAD,           /* read ahead, can fail anytime */
 170        __REQ_THROTTLED,        /* This bio has already been subjected to
 171                                 * throttling rules. Don't do it again. */
 172
 173        /* request only flags */
 174        __REQ_SORTED,           /* elevator knows about this request */
 175        __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 176        __REQ_NOMERGE,          /* don't touch this for merging */
 177        __REQ_STARTED,          /* drive already may have started this one */
 178        __REQ_DONTPREP,         /* don't call prep for this one */
 179        __REQ_QUEUED,           /* uses queueing */
 180        __REQ_ELVPRIV,          /* elevator private data attached */
 181        __REQ_FAILED,           /* set if the request failed */
 182        __REQ_QUIET,            /* don't worry about errors */
 183        __REQ_PREEMPT,          /* set for "ide_preempt" requests and also
 184                                   for requests for which the SCSI "quiesce"
 185                                   state must be ignored. */
 186        __REQ_ALLOCED,          /* request came from our alloc pool */
 187        __REQ_COPY_USER,        /* contains copies of user pages */
 188        __REQ_FLUSH_SEQ,        /* request for flush sequence */
 189        __REQ_IO_STAT,          /* account I/O stat */
 190        __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 191        __REQ_PM,               /* runtime pm request */
 192        __REQ_HASHED,           /* on IO scheduler merge hash */
 193        __REQ_MQ_INFLIGHT,      /* track inflight for MQ */
 194        __REQ_NO_TIMEOUT,       /* requests may never expire */
 195        __REQ_NR_BITS,          /* stops here */
 196};
 197
 198#define REQ_WRITE               (1ULL << __REQ_WRITE)
 199#define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 200#define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 201#define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 202#define REQ_SYNC                (1ULL << __REQ_SYNC)
 203#define REQ_META                (1ULL << __REQ_META)
 204#define REQ_PRIO                (1ULL << __REQ_PRIO)
 205#define REQ_DISCARD             (1ULL << __REQ_DISCARD)
 206#define REQ_WRITE_SAME          (1ULL << __REQ_WRITE_SAME)
 207#define REQ_NOIDLE              (1ULL << __REQ_NOIDLE)
 208#define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 209
 210#define REQ_FAILFAST_MASK \
 211        (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 212#define REQ_COMMON_MASK \
 213        (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 214         REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
 215         REQ_SECURE | REQ_INTEGRITY)
 216#define REQ_CLONE_MASK          REQ_COMMON_MASK
 217
 218#define BIO_NO_ADVANCE_ITER_MASK        (REQ_DISCARD|REQ_WRITE_SAME)
 219
 220/* This mask is used for both bio and request merge checking */
 221#define REQ_NOMERGE_FLAGS \
 222        (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_FLUSH_SEQ)
 223
 224#define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 225#define REQ_THROTTLED           (1ULL << __REQ_THROTTLED)
 226
 227#define REQ_SORTED              (1ULL << __REQ_SORTED)
 228#define REQ_SOFTBARRIER         (1ULL << __REQ_SOFTBARRIER)
 229#define REQ_FUA                 (1ULL << __REQ_FUA)
 230#define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 231#define REQ_STARTED             (1ULL << __REQ_STARTED)
 232#define REQ_DONTPREP            (1ULL << __REQ_DONTPREP)
 233#define REQ_QUEUED              (1ULL << __REQ_QUEUED)
 234#define REQ_ELVPRIV             (1ULL << __REQ_ELVPRIV)
 235#define REQ_FAILED              (1ULL << __REQ_FAILED)
 236#define REQ_QUIET               (1ULL << __REQ_QUIET)
 237#define REQ_PREEMPT             (1ULL << __REQ_PREEMPT)
 238#define REQ_ALLOCED             (1ULL << __REQ_ALLOCED)
 239#define REQ_COPY_USER           (1ULL << __REQ_COPY_USER)
 240#define REQ_FLUSH               (1ULL << __REQ_FLUSH)
 241#define REQ_FLUSH_SEQ           (1ULL << __REQ_FLUSH_SEQ)
 242#define REQ_IO_STAT             (1ULL << __REQ_IO_STAT)
 243#define REQ_MIXED_MERGE         (1ULL << __REQ_MIXED_MERGE)
 244#define REQ_SECURE              (1ULL << __REQ_SECURE)
 245#define REQ_PM                  (1ULL << __REQ_PM)
 246#define REQ_HASHED              (1ULL << __REQ_HASHED)
 247#define REQ_MQ_INFLIGHT         (1ULL << __REQ_MQ_INFLIGHT)
 248#define REQ_NO_TIMEOUT          (1ULL << __REQ_NO_TIMEOUT)
 249
 250#endif /* __LINUX_BLK_TYPES_H */
 251