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 *);
  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 int            bi_flags;       /* status, command, etc */
  50        int                     bi_error;
  51        unsigned long           bi_rw;          /* bottom bits READ/WRITE,
  52                                                 * top bits priority
  53                                                 */
  54
  55        struct bvec_iter        bi_iter;
  56
  57        /* Number of segments in this BIO after
  58         * physical address coalescing is performed.
  59         */
  60        unsigned int            bi_phys_segments;
  61
  62        /*
  63         * To keep track of the max segment size, we account for the
  64         * sizes of the first and last mergeable segments in this bio.
  65         */
  66        unsigned int            bi_seg_front_size;
  67        unsigned int            bi_seg_back_size;
  68
  69        atomic_t                __bi_remaining;
  70
  71        bio_end_io_t            *bi_end_io;
  72
  73        void                    *bi_private;
  74#ifdef CONFIG_BLK_CGROUP
  75        /*
  76         * Optional ioc and css associated with this bio.  Put on bio
  77         * release.  Read comment on top of bio_associate_current().
  78         */
  79        struct io_context       *bi_ioc;
  80        struct cgroup_subsys_state *bi_css;
  81#endif
  82        union {
  83#if defined(CONFIG_BLK_DEV_INTEGRITY)
  84                struct bio_integrity_payload *bi_integrity; /* data integrity */
  85#endif
  86        };
  87
  88        unsigned short          bi_vcnt;        /* how many bio_vec's */
  89
  90        /*
  91         * Everything starting with bi_max_vecs will be preserved by bio_reset()
  92         */
  93
  94        unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
  95
  96        atomic_t                __bi_cnt;       /* pin count */
  97
  98        struct bio_vec          *bi_io_vec;     /* the actual vec list */
  99
 100        struct bio_set          *bi_pool;
 101
 102        /*
 103         * We can inline a number of vecs at the end of the bio, to avoid
 104         * double allocations for a small number of bio_vecs. This member
 105         * MUST obviously be kept at the very end of the bio.
 106         */
 107        struct bio_vec          bi_inline_vecs[0];
 108};
 109
 110#define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 111
 112/*
 113 * bio flags
 114 */
 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_CHAIN       7       /* chained bio, ->bi_remaining in effect */
 122#define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
 123
 124/*
 125 * Flags starting here get preserved by bio_reset() - this includes
 126 * BIO_POOL_IDX()
 127 */
 128#define BIO_RESET_BITS  13
 129#define BIO_OWNS_VEC    13      /* bio_free() should free bvec */
 130
 131/*
 132 * top 4 bits of bio flags indicate the pool this bio came from
 133 */
 134#define BIO_POOL_BITS           (4)
 135#define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 136#define BIO_POOL_OFFSET         (32 - BIO_POOL_BITS)
 137#define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 138#define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 139
 140#endif /* CONFIG_BLOCK */
 141
 142/*
 143 * Request flags.  For use in the cmd_flags field of struct request, and in
 144 * bi_rw of struct bio.  Note that some flags are only valid in either one.
 145 */
 146enum rq_flag_bits {
 147        /* common flags */
 148        __REQ_WRITE,            /* not set, read. set, write */
 149        __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 150        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 151        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 152
 153        __REQ_SYNC,             /* request is sync (sync write or read) */
 154        __REQ_META,             /* metadata io request */
 155        __REQ_PRIO,             /* boost priority in cfq */
 156        __REQ_DISCARD,          /* request to discard sectors */
 157        __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
 158        __REQ_WRITE_SAME,       /* write same block many times */
 159
 160        __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 161        __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 162        __REQ_FUA,              /* forced unit access */
 163        __REQ_FLUSH,            /* request for cache flush */
 164
 165        /* bio only flags */
 166        __REQ_RAHEAD,           /* read ahead, can fail anytime */
 167        __REQ_THROTTLED,        /* This bio has already been subjected to
 168                                 * throttling rules. Don't do it again. */
 169
 170        /* request only flags */
 171        __REQ_SORTED,           /* elevator knows about this request */
 172        __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 173        __REQ_NOMERGE,          /* don't touch this for merging */
 174        __REQ_STARTED,          /* drive already may have started this one */
 175        __REQ_DONTPREP,         /* don't call prep for this one */
 176        __REQ_QUEUED,           /* uses queueing */
 177        __REQ_ELVPRIV,          /* elevator private data attached */
 178        __REQ_FAILED,           /* set if the request failed */
 179        __REQ_QUIET,            /* don't worry about errors */
 180        __REQ_PREEMPT,          /* set for "ide_preempt" requests and also
 181                                   for requests for which the SCSI "quiesce"
 182                                   state must be ignored. */
 183        __REQ_ALLOCED,          /* request came from our alloc pool */
 184        __REQ_COPY_USER,        /* contains copies of user pages */
 185        __REQ_FLUSH_SEQ,        /* request for flush sequence */
 186        __REQ_IO_STAT,          /* account I/O stat */
 187        __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 188        __REQ_PM,               /* runtime pm request */
 189        __REQ_HASHED,           /* on IO scheduler merge hash */
 190        __REQ_MQ_INFLIGHT,      /* track inflight for MQ */
 191        __REQ_NR_BITS,          /* stops here */
 192};
 193
 194#define REQ_WRITE               (1ULL << __REQ_WRITE)
 195#define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 196#define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 197#define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 198#define REQ_SYNC                (1ULL << __REQ_SYNC)
 199#define REQ_META                (1ULL << __REQ_META)
 200#define REQ_PRIO                (1ULL << __REQ_PRIO)
 201#define REQ_DISCARD             (1ULL << __REQ_DISCARD)
 202#define REQ_WRITE_SAME          (1ULL << __REQ_WRITE_SAME)
 203#define REQ_NOIDLE              (1ULL << __REQ_NOIDLE)
 204#define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 205
 206#define REQ_FAILFAST_MASK \
 207        (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 208#define REQ_COMMON_MASK \
 209        (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 210         REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
 211         REQ_SECURE | REQ_INTEGRITY)
 212#define REQ_CLONE_MASK          REQ_COMMON_MASK
 213
 214#define BIO_NO_ADVANCE_ITER_MASK        (REQ_DISCARD|REQ_WRITE_SAME)
 215
 216/* This mask is used for both bio and request merge checking */
 217#define REQ_NOMERGE_FLAGS \
 218        (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_FLUSH_SEQ)
 219
 220#define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 221#define REQ_THROTTLED           (1ULL << __REQ_THROTTLED)
 222
 223#define REQ_SORTED              (1ULL << __REQ_SORTED)
 224#define REQ_SOFTBARRIER         (1ULL << __REQ_SOFTBARRIER)
 225#define REQ_FUA                 (1ULL << __REQ_FUA)
 226#define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 227#define REQ_STARTED             (1ULL << __REQ_STARTED)
 228#define REQ_DONTPREP            (1ULL << __REQ_DONTPREP)
 229#define REQ_QUEUED              (1ULL << __REQ_QUEUED)
 230#define REQ_ELVPRIV             (1ULL << __REQ_ELVPRIV)
 231#define REQ_FAILED              (1ULL << __REQ_FAILED)
 232#define REQ_QUIET               (1ULL << __REQ_QUIET)
 233#define REQ_PREEMPT             (1ULL << __REQ_PREEMPT)
 234#define REQ_ALLOCED             (1ULL << __REQ_ALLOCED)
 235#define REQ_COPY_USER           (1ULL << __REQ_COPY_USER)
 236#define REQ_FLUSH               (1ULL << __REQ_FLUSH)
 237#define REQ_FLUSH_SEQ           (1ULL << __REQ_FLUSH_SEQ)
 238#define REQ_IO_STAT             (1ULL << __REQ_IO_STAT)
 239#define REQ_MIXED_MERGE         (1ULL << __REQ_MIXED_MERGE)
 240#define REQ_SECURE              (1ULL << __REQ_SECURE)
 241#define REQ_PM                  (1ULL << __REQ_PM)
 242#define REQ_HASHED              (1ULL << __REQ_HASHED)
 243#define REQ_MQ_INFLIGHT         (1ULL << __REQ_MQ_INFLIGHT)
 244
 245typedef unsigned int blk_qc_t;
 246#define BLK_QC_T_NONE   -1U
 247#define BLK_QC_T_SHIFT  16
 248
 249static inline bool blk_qc_t_valid(blk_qc_t cookie)
 250{
 251        return cookie != BLK_QC_T_NONE;
 252}
 253
 254static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num)
 255{
 256        return tag | (queue_num << BLK_QC_T_SHIFT);
 257}
 258
 259static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 260{
 261        return cookie >> BLK_QC_T_SHIFT;
 262}
 263
 264static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 265{
 266        return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 267}
 268
 269#endif /* __LINUX_BLK_TYPES_H */
 270