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