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 #ifdef CONFIG_BLOCK
   9
  10 #include <linux/types.h>
  11
  12 struct bio_set;
  13 struct bio;
  14 struct bio_integrity_payload;
  15 struct page;
  16 struct block_device;
  17 struct io_context;
  18 struct cgroup_subsys_state;
  19 typedef void (bio_end_io_t) (struct bio *, int);
  20 typedef void (bio_destructor_t) (struct bio *);
  21
  22 /*
  23  * was unsigned short, but we might as well be ready for > 64kB I/O pages
  24  */
  25 struct bio_vec {
  26         struct page     *bv_page;
  27         unsigned int    bv_len;
  28         unsigned int    bv_offset;
  29 };
  30
  31 struct bvec_iter {
  32         sector_t                bi_sector;      /* device address in 512 byte
  33                                                    sectors */
  34         unsigned int            bi_size;        /* residual I/O count */
  35
  36         unsigned int            bi_idx;         /* current index into bvl_vec */
  37
  38         unsigned int            bi_bvec_done;   /* number of bytes completed in
  39                                                    current bvec */
  40 };
  41
  42 /*
  43  * main unit of I/O for the block layer and lower layers (ie drivers and
  44  * stacking drivers)
  45  */
  46 struct bio {
  47         struct bio              *bi_next;       /* request queue link */
  48         struct block_device     *bi_bdev;
  49         unsigned long           bi_flags;       /* status, command, etc */
  50         unsigned long           bi_rw;          /* bottom bits READ/WRITE,
  51                                                  * top bits priority
  52                                                  */
  53
  54         struct bvec_iter        bi_iter;
  55
  56         /* Number of segments in this BIO after
  57          * physical address coalescing is performed.
  58          */
  59         unsigned int            bi_phys_segments;
  60
  61         /*
  62          * To keep track of the max segment size, we account for the
  63          * sizes of the first and last mergeable segments in this bio.
  64          */
  65         unsigned int            bi_seg_front_size;
  66         unsigned int            bi_seg_back_size;
  67
  68         atomic_t                bi_remaining;
  69
  70         bio_end_io_t            *bi_end_io;
  71
  72         void                    *bi_private;
  73 #ifdef CONFIG_BLK_CGROUP
  74         /*
  75          * Optional ioc and css associated with this bio.  Put on bio
  76          * release.  Read comment on top of bio_associate_current().
  77          */
  78         struct io_context       *bi_ioc;
  79         struct cgroup_subsys_state *bi_css;
  80 #endif
  81 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  82         struct bio_integrity_payload *bi_integrity;  /* data integrity */
  83 #endif
  84
  85         unsigned short          bi_vcnt;        /* how many bio_vec's */
  86
  87         /*
  88          * Everything starting with bi_max_vecs will be preserved by bio_reset()
  89          */
  90
  91         unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
  92
  93         atomic_t                bi_cnt;         /* pin count */
  94
  95         struct bio_vec          *bi_io_vec;     /* the actual vec list */
  96
  97         struct bio_set          *bi_pool;
  98
  99         /*
 100          * We can inline a number of vecs at the end of the bio, to avoid
 101          * double allocations for a small number of bio_vecs. This member
 102          * MUST obviously be kept at the very end of the bio.
 103          */
 104         struct bio_vec          bi_inline_vecs[0];
 105 };
 106
 107 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 108
 109 /*
 110  * bio flags
 111  */
 112 #define BIO_UPTODATE    0       /* ok after I/O completion */
 113 #define BIO_RW_BLOCK    1       /* RW_AHEAD set, and read/write would block */
 114 #define BIO_EOF         2       /* out-out-bounds error */
 115 #define BIO_SEG_VALID   3       /* bi_phys_segments valid */
 116 #define BIO_CLONED      4       /* doesn't own data */
 117 #define BIO_BOUNCED     5       /* bio is a bounce bio */
 118 #define BIO_USER_MAPPED 6       /* contains user pages */
 119 #define BIO_EOPNOTSUPP  7       /* not supported */
 120 #define BIO_NULL_MAPPED 8       /* contains invalid user pages */
 121 #define BIO_FS_INTEGRITY 9      /* fs owns integrity data, not block layer */
 122 #define BIO_QUIET       10      /* Make BIO Quiet */
 123 #define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */
 124 #define BIO_SNAP_STABLE 12      /* bio data must be snapshotted during write */
 125
 126 /*
 127  * Flags starting here get preserved by bio_reset() - this includes
 128  * BIO_POOL_IDX()
 129  */
 130 #define BIO_RESET_BITS  13
 131 #define BIO_OWNS_VEC    13      /* bio_free() should free bvec */
 132
 133 #define bio_flagged(bio, flag)  ((bio)->bi_flags & (1 << (flag)))
 134
 135 /*
 136  * top 4 bits of bio flags indicate the pool this bio came from
 137  */
 138 #define BIO_POOL_BITS           (4)
 139 #define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 140 #define BIO_POOL_OFFSET         (BITS_PER_LONG - BIO_POOL_BITS)
 141 #define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 142 #define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 143
 144 #endif /* CONFIG_BLOCK */
 145
 146 /*
 147  * Request flags.  For use in the cmd_flags field of struct request, and in
 148  * bi_rw of struct bio.  Note that some flags are only valid in either one.
 149  */
 150 enum rq_flag_bits {
 151         /* common flags */
 152         __REQ_WRITE,            /* not set, read. set, write */
 153         __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 154         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 155         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 156
 157         __REQ_SYNC,             /* request is sync (sync write or read) */
 158         __REQ_META,             /* metadata io request */
 159         __REQ_PRIO,             /* boost priority in cfq */
 160         __REQ_DISCARD,          /* request to discard sectors */
 161         __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
 162         __REQ_WRITE_SAME,       /* write same block many times */
 163
 164         __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 165         __REQ_FUA,              /* forced unit access */
 166         __REQ_FLUSH,            /* request for cache flush */
 167
 168         /* bio only flags */
 169         __REQ_RAHEAD,           /* read ahead, can fail anytime */
 170         __REQ_THROTTLED,        /* This bio has already been subjected to
 171                                  * throttling rules. Don't do it again. */
 172
 173         /* request only flags */
 174         __REQ_SORTED,           /* elevator knows about this request */
 175         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 176         __REQ_NOMERGE,          /* don't touch this for merging */
 177         __REQ_STARTED,          /* drive already may have started this one */
 178         __REQ_DONTPREP,         /* don't call prep for this one */
 179         __REQ_QUEUED,           /* uses queueing */
 180         __REQ_ELVPRIV,          /* elevator private data attached */
 181         __REQ_FAILED,           /* set if the request failed */
 182         __REQ_QUIET,            /* don't worry about errors */
 183         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 184         __REQ_ALLOCED,          /* request came from our alloc pool */
 185         __REQ_COPY_USER,        /* contains copies of user pages */
 186         __REQ_FLUSH_SEQ,        /* request for flush sequence */
 187         __REQ_IO_STAT,          /* account I/O stat */
 188         __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 189         __REQ_KERNEL,           /* direct IO to kernel pages */
 190         __REQ_PM,               /* runtime pm request */
 191         __REQ_END,              /* last of chain of requests */
 192         __REQ_HASHED,           /* on IO scheduler merge hash */
 193         __REQ_NR_BITS,          /* stops here */
 194 };
 195
 196 #define REQ_WRITE               (1ULL << __REQ_WRITE)
 197 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 198 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 199 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 200 #define REQ_SYNC                (1ULL << __REQ_SYNC)
 201 #define REQ_META                (1ULL << __REQ_META)
 202 #define REQ_PRIO                (1ULL << __REQ_PRIO)
 203 #define REQ_DISCARD             (1ULL << __REQ_DISCARD)
 204 #define REQ_WRITE_SAME          (1ULL << __REQ_WRITE_SAME)
 205 #define REQ_NOIDLE              (1ULL << __REQ_NOIDLE)
 206
 207 #define REQ_FAILFAST_MASK \
 208         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 209 #define REQ_COMMON_MASK \
 210         (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 211          REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
 212          REQ_SECURE)
 213 #define REQ_CLONE_MASK          REQ_COMMON_MASK
 214
 215 #define BIO_NO_ADVANCE_ITER_MASK        (REQ_DISCARD|REQ_WRITE_SAME)
 216
 217 /* This mask is used for both bio and request merge checking */
 218 #define REQ_NOMERGE_FLAGS \
 219         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 220
 221 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 222 #define REQ_THROTTLED           (1ULL << __REQ_THROTTLED)
 223
 224 #define REQ_SORTED              (1ULL << __REQ_SORTED)
 225 #define REQ_SOFTBARRIER         (1ULL << __REQ_SOFTBARRIER)
 226 #define REQ_FUA                 (1ULL << __REQ_FUA)
 227 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 228 #define REQ_STARTED             (1ULL << __REQ_STARTED)
 229 #define REQ_DONTPREP            (1ULL << __REQ_DONTPREP)
 230 #define REQ_QUEUED              (1ULL << __REQ_QUEUED)
 231 #define REQ_ELVPRIV             (1ULL << __REQ_ELVPRIV)
 232 #define REQ_FAILED              (1ULL << __REQ_FAILED)
 233 #define REQ_QUIET               (1ULL << __REQ_QUIET)
 234 #define REQ_PREEMPT             (1ULL << __REQ_PREEMPT)
 235 #define REQ_ALLOCED             (1ULL << __REQ_ALLOCED)
 236 #define REQ_COPY_USER           (1ULL << __REQ_COPY_USER)
 237 #define REQ_FLUSH               (1ULL << __REQ_FLUSH)
 238 #define REQ_FLUSH_SEQ           (1ULL << __REQ_FLUSH_SEQ)
 239 #define REQ_IO_STAT             (1ULL << __REQ_IO_STAT)
 240 #define REQ_MIXED_MERGE         (1ULL << __REQ_MIXED_MERGE)
 241 #define REQ_SECURE              (1ULL << __REQ_SECURE)
 242 #define REQ_KERNEL              (1ULL << __REQ_KERNEL)
 243 #define REQ_PM                  (1ULL << __REQ_PM)
 244 #define REQ_END                 (1ULL << __REQ_END)
 245 #define REQ_HASHED              (1ULL << __REQ_HASHED)
 246
 247 #endif /* __LINUX_BLK_TYPES_H */