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
  10 struct bio_set;
  11 struct bio;
  12 struct bio_integrity_payload;
  13 struct page;
  14 struct block_device;
  15 struct io_context;
  16 struct cgroup_subsys_state;
  17 typedef void (bio_end_io_t) (struct bio *);
  18 typedef void (bio_destructor_t) (struct bio *);
  19
  20 /*
  21  * was unsigned short, but we might as well be ready for > 64kB I/O pages
  22  */
  23 struct bio_vec {
  24         struct page     *bv_page;
  25         unsigned int    bv_len;
  26         unsigned int    bv_offset;
  27 };
  28
  29 #ifdef CONFIG_BLOCK
  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 int            bi_flags;       /* status, command, etc */
  50         int                     bi_error;
  51         unsigned long           bi_rw;          /* bottom bits READ/WRITE,
  52                                                  * top bits priority
  53                                                  */
  54
  55         struct bvec_iter        bi_iter;
  56
  57         /* Number of segments in this BIO after
  58          * physical address coalescing is performed.
  59          */
  60         unsigned int            bi_phys_segments;
  61
  62         /*
  63          * To keep track of the max segment size, we account for the
  64          * sizes of the first and last mergeable segments in this bio.
  65          */
  66         unsigned int            bi_seg_front_size;
  67         unsigned int            bi_seg_back_size;
  68
  69         atomic_t                __bi_remaining;
  70
  71         bio_end_io_t            *bi_end_io;
  72
  73         void                    *bi_private;
  74 #ifdef CONFIG_BLK_CGROUP
  75         /*
  76          * Optional ioc and css associated with this bio.  Put on bio
  77          * release.  Read comment on top of bio_associate_current().
  78          */
  79         struct io_context       *bi_ioc;
  80         struct cgroup_subsys_state *bi_css;
  81 #endif
  82         union {
  83 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  84                 struct bio_integrity_payload *bi_integrity; /* data integrity */
  85 #endif
  86         };
  87
  88         unsigned short          bi_vcnt;        /* how many bio_vec's */
  89
  90         /*
  91          * Everything starting with bi_max_vecs will be preserved by bio_reset()
  92          */
  93
  94         unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
  95
  96         atomic_t                __bi_cnt;       /* pin count */
  97
  98         struct bio_vec          *bi_io_vec;     /* the actual vec list */
  99
 100         struct bio_set          *bi_pool;
 101
 102         /*
 103          * We can inline a number of vecs at the end of the bio, to avoid
 104          * double allocations for a small number of bio_vecs. This member
 105          * MUST obviously be kept at the very end of the bio.
 106          */
 107         struct bio_vec          bi_inline_vecs[0];
 108 };
 109
 110 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 111
 112 /*
 113  * bio flags
 114  */
 115 #define BIO_SEG_VALID   1       /* bi_phys_segments valid */
 116 #define BIO_CLONED      2       /* doesn't own data */
 117 #define BIO_BOUNCED     3       /* bio is a bounce bio */
 118 #define BIO_USER_MAPPED 4       /* contains user pages */
 119 #define BIO_NULL_MAPPED 5       /* contains invalid user pages */
 120 #define BIO_QUIET       6       /* Make BIO Quiet */
 121 #define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
 122 #define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
 123
 124 /*
 125  * Flags starting here get preserved by bio_reset() - this includes
 126  * BIO_POOL_IDX()
 127  */
 128 #define BIO_RESET_BITS  13
 129 #define BIO_OWNS_VEC    13      /* bio_free() should free bvec */
 130
 131 /*
 132  * top 4 bits of bio flags indicate the pool this bio came from
 133  */
 134 #define BIO_POOL_BITS           (4)
 135 #define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 136 #define BIO_POOL_OFFSET         (32 - BIO_POOL_BITS)
 137 #define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 138 #define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 139
 140 #endif /* CONFIG_BLOCK */
 141
 142 /*
 143  * Request flags.  For use in the cmd_flags field of struct request, and in
 144  * bi_rw of struct bio.  Note that some flags are only valid in either one.
 145  */
 146 enum rq_flag_bits {
 147         /* common flags */
 148         __REQ_WRITE,            /* not set, read. set, write */
 149         __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 150         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 151         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 152
 153         __REQ_SYNC,             /* request is sync (sync write or read) */
 154         __REQ_META,             /* metadata io request */
 155         __REQ_PRIO,             /* boost priority in cfq */
 156         __REQ_DISCARD,          /* request to discard sectors */
 157         __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
 158         __REQ_WRITE_SAME,       /* write same block many times */
 159
 160         __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 161         __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 162         __REQ_FUA,              /* forced unit access */
 163         __REQ_FLUSH,            /* request for cache flush */
 164
 165         /* bio only flags */
 166         __REQ_RAHEAD,           /* read ahead, can fail anytime */
 167         __REQ_THROTTLED,        /* This bio has already been subjected to
 168                                  * throttling rules. Don't do it again. */
 169
 170         /* request only flags */
 171         __REQ_SORTED,           /* elevator knows about this request */
 172         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 173         __REQ_NOMERGE,          /* don't touch this for merging */
 174         __REQ_STARTED,          /* drive already may have started this one */
 175         __REQ_DONTPREP,         /* don't call prep for this one */
 176         __REQ_QUEUED,           /* uses queueing */
 177         __REQ_ELVPRIV,          /* elevator private data attached */
 178         __REQ_FAILED,           /* set if the request failed */
 179         __REQ_QUIET,            /* don't worry about errors */
 180         __REQ_PREEMPT,          /* set for "ide_preempt" requests and also
 181                                    for requests for which the SCSI "quiesce"
 182                                    state must be ignored. */
 183         __REQ_ALLOCED,          /* request came from our alloc pool */
 184         __REQ_COPY_USER,        /* contains copies of user pages */
 185         __REQ_FLUSH_SEQ,        /* request for flush sequence */
 186         __REQ_IO_STAT,          /* account I/O stat */
 187         __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 188         __REQ_PM,               /* runtime pm request */
 189         __REQ_HASHED,           /* on IO scheduler merge hash */
 190         __REQ_MQ_INFLIGHT,      /* track inflight for MQ */
 191         __REQ_NR_BITS,          /* stops here */
 192 };
 193
 194 #define REQ_WRITE               (1ULL << __REQ_WRITE)
 195 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 196 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 197 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 198 #define REQ_SYNC                (1ULL << __REQ_SYNC)
 199 #define REQ_META                (1ULL << __REQ_META)
 200 #define REQ_PRIO                (1ULL << __REQ_PRIO)
 201 #define REQ_DISCARD             (1ULL << __REQ_DISCARD)
 202 #define REQ_WRITE_SAME          (1ULL << __REQ_WRITE_SAME)
 203 #define REQ_NOIDLE              (1ULL << __REQ_NOIDLE)
 204 #define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 205
 206 #define REQ_FAILFAST_MASK \
 207         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 208 #define REQ_COMMON_MASK \
 209         (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
 210          REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
 211          REQ_SECURE | REQ_INTEGRITY)
 212 #define REQ_CLONE_MASK          REQ_COMMON_MASK
 213
 214 #define BIO_NO_ADVANCE_ITER_MASK        (REQ_DISCARD|REQ_WRITE_SAME)
 215
 216 /* This mask is used for both bio and request merge checking */
 217 #define REQ_NOMERGE_FLAGS \
 218         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_FLUSH_SEQ)
 219
 220 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 221 #define REQ_THROTTLED           (1ULL << __REQ_THROTTLED)
 222
 223 #define REQ_SORTED              (1ULL << __REQ_SORTED)
 224 #define REQ_SOFTBARRIER         (1ULL << __REQ_SOFTBARRIER)
 225 #define REQ_FUA                 (1ULL << __REQ_FUA)
 226 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 227 #define REQ_STARTED             (1ULL << __REQ_STARTED)
 228 #define REQ_DONTPREP            (1ULL << __REQ_DONTPREP)
 229 #define REQ_QUEUED              (1ULL << __REQ_QUEUED)
 230 #define REQ_ELVPRIV             (1ULL << __REQ_ELVPRIV)
 231 #define REQ_FAILED              (1ULL << __REQ_FAILED)
 232 #define REQ_QUIET               (1ULL << __REQ_QUIET)
 233 #define REQ_PREEMPT             (1ULL << __REQ_PREEMPT)
 234 #define REQ_ALLOCED             (1ULL << __REQ_ALLOCED)
 235 #define REQ_COPY_USER           (1ULL << __REQ_COPY_USER)
 236 #define REQ_FLUSH               (1ULL << __REQ_FLUSH)
 237 #define REQ_FLUSH_SEQ           (1ULL << __REQ_FLUSH_SEQ)
 238 #define REQ_IO_STAT             (1ULL << __REQ_IO_STAT)
 239 #define REQ_MIXED_MERGE         (1ULL << __REQ_MIXED_MERGE)
 240 #define REQ_SECURE              (1ULL << __REQ_SECURE)
 241 #define REQ_PM                  (1ULL << __REQ_PM)
 242 #define REQ_HASHED              (1ULL << __REQ_HASHED)
 243 #define REQ_MQ_INFLIGHT         (1ULL << __REQ_MQ_INFLIGHT)
 244
 245 typedef unsigned int blk_qc_t;
 246 #define BLK_QC_T_NONE   -1U
 247 #define BLK_QC_T_SHIFT  16
 248
 249 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 250 {
 251         return cookie != BLK_QC_T_NONE;
 252 }
 253
 254 static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num)
 255 {
 256         return tag | (queue_num << BLK_QC_T_SHIFT);
 257 }
 258
 259 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 260 {
 261         return cookie >> BLK_QC_T_SHIFT;
 262 }
 263
 264 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 265 {
 266         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 267 }
 268
 269 #endif /* __LINUX_BLK_TYPES_H */