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