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 struct 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  */
  28 struct 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
 159 enum 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
 189 enum 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 */
 239 static 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
 245 static 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  */
 254 static 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  */
 264 static 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
 270 typedef 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
 275 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 276 {
 277         return cookie != BLK_QC_T_NONE;
 278 }
 279
 280 static 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
 291 static 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
 296 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 297 {
 298         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 299 }
 300
 301 static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
 302 {
 303         return (cookie & BLK_QC_T_INTERNAL) != 0;
 304 }
 305
 306 struct 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 */