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  * Block error status values.  See block/blk-core:blk_errors for the details.
  22  */
  23 typedef u8 __bitwise blk_status_t;
  24 #define BLK_STS_OK 0
  25 #define BLK_STS_NOTSUPP         ((__force blk_status_t)1)
  26 #define BLK_STS_TIMEOUT         ((__force blk_status_t)2)
  27 #define BLK_STS_NOSPC           ((__force blk_status_t)3)
  28 #define BLK_STS_TRANSPORT       ((__force blk_status_t)4)
  29 #define BLK_STS_TARGET          ((__force blk_status_t)5)
  30 #define BLK_STS_NEXUS           ((__force blk_status_t)6)
  31 #define BLK_STS_MEDIUM          ((__force blk_status_t)7)
  32 #define BLK_STS_PROTECTION      ((__force blk_status_t)8)
  33 #define BLK_STS_RESOURCE        ((__force blk_status_t)9)
  34 #define BLK_STS_IOERR           ((__force blk_status_t)10)
  35
  36 /* hack for device mapper, don't use elsewhere: */
  37 #define BLK_STS_DM_REQUEUE    ((__force blk_status_t)11)
  38
  39 #define BLK_STS_AGAIN           ((__force blk_status_t)12)
  40
  41 struct blk_issue_stat {
  42         u64 stat;
  43 };
  44
  45 /*
  46  * main unit of I/O for the block layer and lower layers (ie drivers and
  47  * stacking drivers)
  48  */
  49 struct bio {
  50         struct bio              *bi_next;       /* request queue link */
  51         struct gendisk          *bi_disk;
  52         u8                      bi_partno;
  53         blk_status_t            bi_status;
  54         unsigned int            bi_opf;         /* bottom bits req flags,
  55                                                  * top bits REQ_OP. Use
  56                                                  * accessors.
  57                                                  */
  58         unsigned short          bi_flags;       /* status, etc and bvec pool number */
  59         unsigned short          bi_ioprio;
  60         unsigned short          bi_write_hint;
  61
  62         struct bvec_iter        bi_iter;
  63
  64         /* Number of segments in this BIO after
  65          * physical address coalescing is performed.
  66          */
  67         unsigned int            bi_phys_segments;
  68
  69         /*
  70          * To keep track of the max segment size, we account for the
  71          * sizes of the first and last mergeable segments in this bio.
  72          */
  73         unsigned int            bi_seg_front_size;
  74         unsigned int            bi_seg_back_size;
  75
  76         atomic_t                __bi_remaining;
  77
  78         bio_end_io_t            *bi_end_io;
  79
  80         void                    *bi_private;
  81 #ifdef CONFIG_BLK_CGROUP
  82         /*
  83          * Optional ioc and css associated with this bio.  Put on bio
  84          * release.  Read comment on top of bio_associate_current().
  85          */
  86         struct io_context       *bi_ioc;
  87         struct cgroup_subsys_state *bi_css;
  88 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
  89         void                    *bi_cg_private;
  90         struct blk_issue_stat   bi_issue_stat;
  91 #endif
  92 #endif
  93         union {
  94 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  95                 struct bio_integrity_payload *bi_integrity; /* data integrity */
  96 #endif
  97         };
  98
  99         unsigned short          bi_vcnt;        /* how many bio_vec's */
 100
 101         /*
 102          * Everything starting with bi_max_vecs will be preserved by bio_reset()
 103          */
 104
 105         unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
 106
 107         atomic_t                __bi_cnt;       /* pin count */
 108
 109         struct bio_vec          *bi_io_vec;     /* the actual vec list */
 110
 111         struct bio_set          *bi_pool;
 112
 113         /*
 114          * We can inline a number of vecs at the end of the bio, to avoid
 115          * double allocations for a small number of bio_vecs. This member
 116          * MUST obviously be kept at the very end of the bio.
 117          */
 118         struct bio_vec          bi_inline_vecs[0];
 119 };
 120
 121 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 122
 123 /*
 124  * bio flags
 125  */
 126 #define BIO_SEG_VALID   1       /* bi_phys_segments valid */
 127 #define BIO_CLONED      2       /* doesn't own data */
 128 #define BIO_BOUNCED     3       /* bio is a bounce bio */
 129 #define BIO_USER_MAPPED 4       /* contains user pages */
 130 #define BIO_NULL_MAPPED 5       /* contains invalid user pages */
 131 #define BIO_QUIET       6       /* Make BIO Quiet */
 132 #define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
 133 #define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
 134 #define BIO_THROTTLED   9       /* This bio has already been subjected to
 135                                  * throttling rules. Don't do it again. */
 136 #define BIO_TRACE_COMPLETION 10 /* bio_endio() should trace the final completion
 137                                  * of this bio. */
 138 /* See BVEC_POOL_OFFSET below before adding new flags */
 139
 140 /*
 141  * We support 6 different bvec pools, the last one is magic in that it
 142  * is backed by a mempool.
 143  */
 144 #define BVEC_POOL_NR            6
 145 #define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)
 146
 147 /*
 148  * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
 149  * 1 to the actual index so that 0 indicates that there are no bvecs to be
 150  * freed.
 151  */
 152 #define BVEC_POOL_BITS          (3)
 153 #define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
 154 #define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
 155 #if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
 156 # error "BVEC_POOL_BITS is too small"
 157 #endif
 158
 159 /*
 160  * Flags starting here get preserved by bio_reset() - this includes
 161  * only BVEC_POOL_IDX()
 162  */
 163 #define BIO_RESET_BITS  BVEC_POOL_OFFSET
 164
 165 /*
 166  * Operations and flags common to the bio and request structures.
 167  * We use 8 bits for encoding the operation, and the remaining 24 for flags.
 168  *
 169  * The least significant bit of the operation number indicates the data
 170  * transfer direction:
 171  *
 172  *   - if the least significant bit is set transfers are TO the device
 173  *   - if the least significant bit is not set transfers are FROM the device
 174  *
 175  * If a operation does not transfer data the least significant bit has no
 176  * meaning.
 177  */
 178 #define REQ_OP_BITS     8
 179 #define REQ_OP_MASK     ((1 << REQ_OP_BITS) - 1)
 180 #define REQ_FLAG_BITS   24
 181
 182 enum req_opf {
 183         /* read sectors from the device */
 184         REQ_OP_READ             = 0,
 185         /* write sectors to the device */
 186         REQ_OP_WRITE            = 1,
 187         /* flush the volatile write cache */
 188         REQ_OP_FLUSH            = 2,
 189         /* discard sectors */
 190         REQ_OP_DISCARD          = 3,
 191         /* get zone information */
 192         REQ_OP_ZONE_REPORT      = 4,
 193         /* securely erase sectors */
 194         REQ_OP_SECURE_ERASE     = 5,
 195         /* seset a zone write pointer */
 196         REQ_OP_ZONE_RESET       = 6,
 197         /* write the same sector many times */
 198         REQ_OP_WRITE_SAME       = 7,
 199         /* write the zero filled sector many times */
 200         REQ_OP_WRITE_ZEROES     = 9,
 201
 202         /* SCSI passthrough using struct scsi_request */
 203         REQ_OP_SCSI_IN          = 32,
 204         REQ_OP_SCSI_OUT         = 33,
 205         /* Driver private requests */
 206         REQ_OP_DRV_IN           = 34,
 207         REQ_OP_DRV_OUT          = 35,
 208
 209         REQ_OP_LAST,
 210 };
 211
 212 enum req_flag_bits {
 213         __REQ_FAILFAST_DEV =    /* no driver retries of device errors */
 214                 REQ_OP_BITS,
 215         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 216         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 217         __REQ_SYNC,             /* request is sync (sync write or read) */
 218         __REQ_META,             /* metadata io request */
 219         __REQ_PRIO,             /* boost priority in cfq */
 220         __REQ_NOMERGE,          /* don't touch this for merging */
 221         __REQ_IDLE,             /* anticipate more IO after this one */
 222         __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 223         __REQ_FUA,              /* forced unit access */
 224         __REQ_PREFLUSH,         /* request for cache flush */
 225         __REQ_RAHEAD,           /* read ahead, can fail anytime */
 226         __REQ_BACKGROUND,       /* background IO */
 227
 228         /* command specific flags for REQ_OP_WRITE_ZEROES: */
 229         __REQ_NOUNMAP,          /* do not free blocks when zeroing */
 230
 231         __REQ_NOWAIT,           /* Don't wait if request will block */
 232         __REQ_NR_BITS,          /* stops here */
 233 };
 234
 235 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 236 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 237 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 238 #define REQ_SYNC                (1ULL << __REQ_SYNC)
 239 #define REQ_META                (1ULL << __REQ_META)
 240 #define REQ_PRIO                (1ULL << __REQ_PRIO)
 241 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 242 #define REQ_IDLE                (1ULL << __REQ_IDLE)
 243 #define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 244 #define REQ_FUA                 (1ULL << __REQ_FUA)
 245 #define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
 246 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 247 #define REQ_BACKGROUND          (1ULL << __REQ_BACKGROUND)
 248
 249 #define REQ_NOUNMAP             (1ULL << __REQ_NOUNMAP)
 250 #define REQ_NOWAIT              (1ULL << __REQ_NOWAIT)
 251
 252 #define REQ_FAILFAST_MASK \
 253         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 254
 255 #define REQ_NOMERGE_FLAGS \
 256         (REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
 257
 258 #define bio_op(bio) \
 259         ((bio)->bi_opf & REQ_OP_MASK)
 260 #define req_op(req) \
 261         ((req)->cmd_flags & REQ_OP_MASK)
 262
 263 /* obsolete, don't use in new code */
 264 static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
 265                 unsigned op_flags)
 266 {
 267         bio->bi_opf = op | op_flags;
 268 }
 269
 270 static inline bool op_is_write(unsigned int op)
 271 {
 272         return (op & 1);
 273 }
 274
 275 /*
 276  * Check if the bio or request is one that needs special treatment in the
 277  * flush state machine.
 278  */
 279 static inline bool op_is_flush(unsigned int op)
 280 {
 281         return op & (REQ_FUA | REQ_PREFLUSH);
 282 }
 283
 284 /*
 285  * Reads are always treated as synchronous, as are requests with the FUA or
 286  * PREFLUSH flag.  Other operations may be marked as synchronous using the
 287  * REQ_SYNC flag.
 288  */
 289 static inline bool op_is_sync(unsigned int op)
 290 {
 291         return (op & REQ_OP_MASK) == REQ_OP_READ ||
 292                 (op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
 293 }
 294
 295 typedef unsigned int blk_qc_t;
 296 #define BLK_QC_T_NONE           -1U
 297 #define BLK_QC_T_SHIFT          16
 298 #define BLK_QC_T_INTERNAL       (1U << 31)
 299
 300 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 301 {
 302         return cookie != BLK_QC_T_NONE;
 303 }
 304
 305 static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
 306                                        bool internal)
 307 {
 308         blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
 309
 310         if (internal)
 311                 ret |= BLK_QC_T_INTERNAL;
 312
 313         return ret;
 314 }
 315
 316 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 317 {
 318         return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
 319 }
 320
 321 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 322 {
 323         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 324 }
 325
 326 static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
 327 {
 328         return (cookie & BLK_QC_T_INTERNAL) != 0;
 329 }
 330
 331 struct blk_rq_stat {
 332         u64 mean;
 333         u64 min;
 334         u64 max;
 335         u32 nr_samples;
 336         u64 batch;
 337 };
 338
 339 #endif /* __LINUX_BLK_TYPES_H */