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#include <linux/bvec.h>
  10
  11struct bio_set;
  12struct bio;
  13struct bio_integrity_payload;
  14struct page;
  15struct block_device;
  16struct io_context;
  17struct cgroup_subsys_state;
  18typedef void (bio_end_io_t) (struct bio *);
  19
  20struct blk_issue_stat {
  21        u64 stat;
  22};
  23
  24/*
  25 * main unit of I/O for the block layer and lower layers (ie drivers and
  26 * stacking drivers)
  27 */
  28struct bio {
  29        struct bio              *bi_next;       /* request queue link */
  30        struct block_device     *bi_bdev;
  31        int                     bi_error;
  32        unsigned int            bi_opf;         /* bottom bits req flags,
  33                                                 * top bits REQ_OP. Use
  34                                                 * accessors.
  35                                                 */
  36        unsigned short          bi_flags;       /* status, etc and bvec pool number */
  37        unsigned short          bi_ioprio;
  38
  39        struct bvec_iter        bi_iter;
  40
  41        /* Number of segments in this BIO after
  42         * physical address coalescing is performed.
  43         */
  44        unsigned int            bi_phys_segments;
  45
  46        /*
  47         * To keep track of the max segment size, we account for the
  48         * sizes of the first and last mergeable segments in this bio.
  49         */
  50        unsigned int            bi_seg_front_size;
  51        unsigned int            bi_seg_back_size;
  52
  53        atomic_t                __bi_remaining;
  54
  55        bio_end_io_t            *bi_end_io;
  56
  57        void                    *bi_private;
  58#ifdef CONFIG_BLK_CGROUP
  59        /*
  60         * Optional ioc and css associated with this bio.  Put on bio
  61         * release.  Read comment on top of bio_associate_current().
  62         */
  63        struct io_context       *bi_ioc;
  64        struct cgroup_subsys_state *bi_css;
  65#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
  66        void                    *bi_cg_private;
  67        struct blk_issue_stat   bi_issue_stat;
  68#endif
  69#endif
  70        union {
  71#if defined(CONFIG_BLK_DEV_INTEGRITY)
  72                struct bio_integrity_payload *bi_integrity; /* data integrity */
  73#endif
  74        };
  75
  76        unsigned short          bi_vcnt;        /* how many bio_vec's */
  77
  78        /*
  79         * Everything starting with bi_max_vecs will be preserved by bio_reset()
  80         */
  81
  82        unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
  83
  84        atomic_t                __bi_cnt;       /* pin count */
  85
  86        struct bio_vec          *bi_io_vec;     /* the actual vec list */
  87
  88        struct bio_set          *bi_pool;
  89
  90        /*
  91         * We can inline a number of vecs at the end of the bio, to avoid
  92         * double allocations for a small number of bio_vecs. This member
  93         * MUST obviously be kept at the very end of the bio.
  94         */
  95        struct bio_vec          bi_inline_vecs[0];
  96};
  97
  98#define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
  99
 100/*
 101 * bio flags
 102 */
 103#define BIO_SEG_VALID   1       /* bi_phys_segments valid */
 104#define BIO_CLONED      2       /* doesn't own data */
 105#define BIO_BOUNCED     3       /* bio is a bounce bio */
 106#define BIO_USER_MAPPED 4       /* contains user pages */
 107#define BIO_NULL_MAPPED 5       /* contains invalid user pages */
 108#define BIO_QUIET       6       /* Make BIO Quiet */
 109#define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
 110#define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
 111#define BIO_THROTTLED   9       /* This bio has already been subjected to
 112                                 * throttling rules. Don't do it again. */
 113#define BIO_TRACE_COMPLETION 10 /* bio_endio() should trace the final completion
 114                                 * of this bio. */
 115/* See BVEC_POOL_OFFSET below before adding new flags */
 116
 117/*
 118 * We support 6 different bvec pools, the last one is magic in that it
 119 * is backed by a mempool.
 120 */
 121#define BVEC_POOL_NR            6
 122#define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)
 123
 124/*
 125 * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
 126 * 1 to the actual index so that 0 indicates that there are no bvecs to be
 127 * freed.
 128 */
 129#define BVEC_POOL_BITS          (3)
 130#define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
 131#define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
 132#if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
 133# error "BVEC_POOL_BITS is too small"
 134#endif
 135
 136/*
 137 * Flags starting here get preserved by bio_reset() - this includes
 138 * only BVEC_POOL_IDX()
 139 */
 140#define BIO_RESET_BITS  BVEC_POOL_OFFSET
 141
 142/*
 143 * Operations and flags common to the bio and request structures.
 144 * We use 8 bits for encoding the operation, and the remaining 24 for flags.
 145 *
 146 * The least significant bit of the operation number indicates the data
 147 * transfer direction:
 148 *
 149 *   - if the least significant bit is set transfers are TO the device
 150 *   - if the least significant bit is not set transfers are FROM the device
 151 *
 152 * If a operation does not transfer data the least significant bit has no
 153 * meaning.
 154 */
 155#define REQ_OP_BITS     8
 156#define REQ_OP_MASK     ((1 << REQ_OP_BITS) - 1)
 157#define REQ_FLAG_BITS   24
 158
 159enum req_opf {
 160        /* read sectors from the device */
 161        REQ_OP_READ             = 0,
 162        /* write sectors to the device */
 163        REQ_OP_WRITE            = 1,
 164        /* flush the volatile write cache */
 165        REQ_OP_FLUSH            = 2,
 166        /* discard sectors */
 167        REQ_OP_DISCARD          = 3,
 168        /* get zone information */
 169        REQ_OP_ZONE_REPORT      = 4,
 170        /* securely erase sectors */
 171        REQ_OP_SECURE_ERASE     = 5,
 172        /* seset a zone write pointer */
 173        REQ_OP_ZONE_RESET       = 6,
 174        /* write the same sector many times */
 175        REQ_OP_WRITE_SAME       = 7,
 176        /* write the zero filled sector many times */
 177        REQ_OP_WRITE_ZEROES     = 9,
 178
 179        /* SCSI passthrough using struct scsi_request */
 180        REQ_OP_SCSI_IN          = 32,
 181        REQ_OP_SCSI_OUT         = 33,
 182        /* Driver private requests */
 183        REQ_OP_DRV_IN           = 34,
 184        REQ_OP_DRV_OUT          = 35,
 185
 186        REQ_OP_LAST,
 187};
 188
 189enum req_flag_bits {
 190        __REQ_FAILFAST_DEV =    /* no driver retries of device errors */
 191                REQ_OP_BITS,
 192        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 193        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 194        __REQ_SYNC,             /* request is sync (sync write or read) */
 195        __REQ_META,             /* metadata io request */
 196        __REQ_PRIO,             /* boost priority in cfq */
 197        __REQ_NOMERGE,          /* don't touch this for merging */
 198        __REQ_IDLE,             /* anticipate more IO after this one */
 199        __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 200        __REQ_FUA,              /* forced unit access */
 201        __REQ_PREFLUSH,         /* request for cache flush */
 202        __REQ_RAHEAD,           /* read ahead, can fail anytime */
 203        __REQ_BACKGROUND,       /* background IO */
 204
 205        /* command specific flags for REQ_OP_WRITE_ZEROES: */
 206        __REQ_NOUNMAP,          /* do not free blocks when zeroing */
 207
 208        __REQ_NR_BITS,          /* stops here */
 209};
 210
 211#define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 212#define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 213#define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 214#define REQ_SYNC                (1ULL << __REQ_SYNC)
 215#define REQ_META                (1ULL << __REQ_META)
 216#define REQ_PRIO                (1ULL << __REQ_PRIO)
 217#define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 218#define REQ_IDLE                (1ULL << __REQ_IDLE)
 219#define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 220#define REQ_FUA                 (1ULL << __REQ_FUA)
 221#define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
 222#define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 223#define REQ_BACKGROUND          (1ULL << __REQ_BACKGROUND)
 224
 225#define REQ_NOUNMAP             (1ULL << __REQ_NOUNMAP)
 226
 227#define REQ_FAILFAST_MASK \
 228        (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 229
 230#define REQ_NOMERGE_FLAGS \
 231        (REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
 232
 233#define bio_op(bio) \
 234        ((bio)->bi_opf & REQ_OP_MASK)
 235#define req_op(req) \
 236        ((req)->cmd_flags & REQ_OP_MASK)
 237
 238/* obsolete, don't use in new code */
 239static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
 240                unsigned op_flags)
 241{
 242        bio->bi_opf = op | op_flags;
 243}
 244
 245static inline bool op_is_write(unsigned int op)
 246{
 247        return (op & 1);
 248}
 249
 250/*
 251 * Check if the bio or request is one that needs special treatment in the
 252 * flush state machine.
 253 */
 254static inline bool op_is_flush(unsigned int op)
 255{
 256        return op & (REQ_FUA | REQ_PREFLUSH);
 257}
 258
 259/*
 260 * Reads are always treated as synchronous, as are requests with the FUA or
 261 * PREFLUSH flag.  Other operations may be marked as synchronous using the
 262 * REQ_SYNC flag.
 263 */
 264static inline bool op_is_sync(unsigned int op)
 265{
 266        return (op & REQ_OP_MASK) == REQ_OP_READ ||
 267                (op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
 268}
 269
 270typedef unsigned int blk_qc_t;
 271#define BLK_QC_T_NONE           -1U
 272#define BLK_QC_T_SHIFT          16
 273#define BLK_QC_T_INTERNAL       (1U << 31)
 274
 275static inline bool blk_qc_t_valid(blk_qc_t cookie)
 276{
 277        return cookie != BLK_QC_T_NONE;
 278}
 279
 280static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
 281                                       bool internal)
 282{
 283        blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
 284
 285        if (internal)
 286                ret |= BLK_QC_T_INTERNAL;
 287
 288        return ret;
 289}
 290
 291static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 292{
 293        return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
 294}
 295
 296static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 297{
 298        return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 299}
 300
 301static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
 302{
 303        return (cookie & BLK_QC_T_INTERNAL) != 0;
 304}
 305
 306struct blk_rq_stat {
 307        s64 mean;
 308        u64 min;
 309        u64 max;
 310        s32 nr_samples;
 311        s32 nr_batch;
 312        u64 batch;
 313};
 314
 315#endif /* __LINUX_BLK_TYPES_H */
 316