include/linux/blk_types.h

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