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 typedef void (bio_destructor_t) (struct bio *);
  20
  21 enum req_op {
  22         REQ_OP_READ,
  23         REQ_OP_WRITE,
  24         REQ_OP_DISCARD,         /* request to discard sectors */
  25         REQ_OP_SECURE_ERASE,    /* request to securely erase sectors */
  26         REQ_OP_WRITE_SAME,      /* write same block many times */
  27         REQ_OP_FLUSH,           /* request for cache flush */
  28 };
  29
  30 #define REQ_OP_BITS 3
  31
  32 #ifdef CONFIG_BLOCK
  33 /*
  34  * main unit of I/O for the block layer and lower layers (ie drivers and
  35  * stacking drivers)
  36  */
  37 struct bio {
  38         struct bio              *bi_next;       /* request queue link */
  39         struct block_device     *bi_bdev;
  40         int                     bi_error;
  41         unsigned int            bi_rw;          /* bottom bits req flags,
  42                                                  * top bits REQ_OP
  43                                                  */
  44         unsigned short          bi_flags;       /* status, command, etc */
  45         unsigned short          bi_ioprio;
  46
  47         struct bvec_iter        bi_iter;
  48
  49         /* Number of segments in this BIO after
  50          * physical address coalescing is performed.
  51          */
  52         unsigned int            bi_phys_segments;
  53
  54         /*
  55          * To keep track of the max segment size, we account for the
  56          * sizes of the first and last mergeable segments in this bio.
  57          */
  58         unsigned int            bi_seg_front_size;
  59         unsigned int            bi_seg_back_size;
  60
  61         atomic_t                __bi_remaining;
  62
  63         bio_end_io_t            *bi_end_io;
  64
  65         void                    *bi_private;
  66 #ifdef CONFIG_BLK_CGROUP
  67         /*
  68          * Optional ioc and css associated with this bio.  Put on bio
  69          * release.  Read comment on top of bio_associate_current().
  70          */
  71         struct io_context       *bi_ioc;
  72         struct cgroup_subsys_state *bi_css;
  73 #endif
  74         union {
  75 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  76                 struct bio_integrity_payload *bi_integrity; /* data integrity */
  77 #endif
  78         };
  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_OP_SHIFT    (8 * sizeof(unsigned int) - REQ_OP_BITS)
 103 #define bio_op(bio)     ((bio)->bi_rw >> BIO_OP_SHIFT)
 104
 105 #define bio_set_op_attrs(bio, op, op_flags) do {                \
 106         WARN_ON(op >= (1 << REQ_OP_BITS));                      \
 107         (bio)->bi_rw &= ((1 << BIO_OP_SHIFT) - 1);              \
 108         (bio)->bi_rw |= ((unsigned int) (op) << BIO_OP_SHIFT);  \
 109         (bio)->bi_rw |= op_flags;                               \
 110 } while (0)
 111
 112 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 113
 114 /*
 115  * bio flags
 116  */
 117 #define BIO_SEG_VALID   1       /* bi_phys_segments valid */
 118 #define BIO_CLONED      2       /* doesn't own data */
 119 #define BIO_BOUNCED     3       /* bio is a bounce bio */
 120 #define BIO_USER_MAPPED 4       /* contains user pages */
 121 #define BIO_NULL_MAPPED 5       /* contains invalid user pages */
 122 #define BIO_QUIET       6       /* Make BIO Quiet */
 123 #define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
 124 #define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
 125
 126 /*
 127  * Flags starting here get preserved by bio_reset() - this includes
 128  * BVEC_POOL_IDX()
 129  */
 130 #define BIO_RESET_BITS  10
 131
 132 /*
 133  * We support 6 different bvec pools, the last one is magic in that it
 134  * is backed by a mempool.
 135  */
 136 #define BVEC_POOL_NR            6
 137 #define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)
 138
 139 /*
 140  * Top 4 bits of bio flags indicate the pool the bvecs came from.  We add
 141  * 1 to the actual index so that 0 indicates that there are no bvecs to be
 142  * freed.
 143  */
 144 #define BVEC_POOL_BITS          (4)
 145 #define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
 146 #define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
 147
 148 #endif /* CONFIG_BLOCK */
 149
 150 /*
 151  * Request flags.  For use in the cmd_flags field of struct request, and in
 152  * bi_rw of struct bio.  Note that some flags are only valid in either one.
 153  */
 154 enum rq_flag_bits {
 155         /* common flags */
 156         __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 157         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 158         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 159
 160         __REQ_SYNC,             /* request is sync (sync write or read) */
 161         __REQ_META,             /* metadata io request */
 162         __REQ_PRIO,             /* boost priority in cfq */
 163
 164         __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 165         __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 166         __REQ_FUA,              /* forced unit access */
 167         __REQ_PREFLUSH,         /* request for cache flush */
 168
 169         /* bio only flags */
 170         __REQ_RAHEAD,           /* read ahead, can fail anytime */
 171         __REQ_THROTTLED,        /* This bio has already been subjected to
 172                                  * throttling rules. Don't do it again. */
 173
 174         /* request only flags */
 175         __REQ_SORTED,           /* elevator knows about this request */
 176         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 177         __REQ_NOMERGE,          /* don't touch this for merging */
 178         __REQ_STARTED,          /* drive already may have started this one */
 179         __REQ_DONTPREP,         /* don't call prep for this one */
 180         __REQ_QUEUED,           /* uses queueing */
 181         __REQ_ELVPRIV,          /* elevator private data attached */
 182         __REQ_FAILED,           /* set if the request failed */
 183         __REQ_QUIET,            /* don't worry about errors */
 184         __REQ_PREEMPT,          /* set for "ide_preempt" requests and also
 185                                    for requests for which the SCSI "quiesce"
 186                                    state must be ignored. */
 187         __REQ_ALLOCED,          /* request came from our alloc pool */
 188         __REQ_COPY_USER,        /* contains copies of user pages */
 189         __REQ_FLUSH_SEQ,        /* request for flush sequence */
 190         __REQ_IO_STAT,          /* account I/O stat */
 191         __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 192         __REQ_PM,               /* runtime pm request */
 193         __REQ_HASHED,           /* on IO scheduler merge hash */
 194         __REQ_MQ_INFLIGHT,      /* track inflight for MQ */
 195         __REQ_NR_BITS,          /* stops here */
 196 };
 197
 198 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 199 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 200 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 201 #define REQ_SYNC                (1ULL << __REQ_SYNC)
 202 #define REQ_META                (1ULL << __REQ_META)
 203 #define REQ_PRIO                (1ULL << __REQ_PRIO)
 204 #define REQ_NOIDLE              (1ULL << __REQ_NOIDLE)
 205 #define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 206
 207 #define REQ_FAILFAST_MASK \
 208         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 209 #define REQ_COMMON_MASK \
 210         (REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | REQ_NOIDLE | \
 211          REQ_PREFLUSH | REQ_FUA | REQ_INTEGRITY | REQ_NOMERGE)
 212 #define REQ_CLONE_MASK          REQ_COMMON_MASK
 213
 214 /* This mask is used for both bio and request merge checking */
 215 #define REQ_NOMERGE_FLAGS \
 216         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_PREFLUSH | REQ_FUA | REQ_FLUSH_SEQ)
 217
 218 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 219 #define REQ_THROTTLED           (1ULL << __REQ_THROTTLED)
 220
 221 #define REQ_SORTED              (1ULL << __REQ_SORTED)
 222 #define REQ_SOFTBARRIER         (1ULL << __REQ_SOFTBARRIER)
 223 #define REQ_FUA                 (1ULL << __REQ_FUA)
 224 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 225 #define REQ_STARTED             (1ULL << __REQ_STARTED)
 226 #define REQ_DONTPREP            (1ULL << __REQ_DONTPREP)
 227 #define REQ_QUEUED              (1ULL << __REQ_QUEUED)
 228 #define REQ_ELVPRIV             (1ULL << __REQ_ELVPRIV)
 229 #define REQ_FAILED              (1ULL << __REQ_FAILED)
 230 #define REQ_QUIET               (1ULL << __REQ_QUIET)
 231 #define REQ_PREEMPT             (1ULL << __REQ_PREEMPT)
 232 #define REQ_ALLOCED             (1ULL << __REQ_ALLOCED)
 233 #define REQ_COPY_USER           (1ULL << __REQ_COPY_USER)
 234 #define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
 235 #define REQ_FLUSH_SEQ           (1ULL << __REQ_FLUSH_SEQ)
 236 #define REQ_IO_STAT             (1ULL << __REQ_IO_STAT)
 237 #define REQ_MIXED_MERGE         (1ULL << __REQ_MIXED_MERGE)
 238 #define REQ_PM                  (1ULL << __REQ_PM)
 239 #define REQ_HASHED              (1ULL << __REQ_HASHED)
 240 #define REQ_MQ_INFLIGHT         (1ULL << __REQ_MQ_INFLIGHT)
 241
 242 typedef unsigned int blk_qc_t;
 243 #define BLK_QC_T_NONE   -1U
 244 #define BLK_QC_T_SHIFT  16
 245
 246 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 247 {
 248         return cookie != BLK_QC_T_NONE;
 249 }
 250
 251 static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num)
 252 {
 253         return tag | (queue_num << BLK_QC_T_SHIFT);
 254 }
 255
 256 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 257 {
 258         return cookie >> BLK_QC_T_SHIFT;
 259 }
 260
 261 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 262 {
 263         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 264 }
 265
 266 #endif /* __LINUX_BLK_TYPES_H */