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 #ifdef CONFIG_BLOCK
  22 /*
  23  * main unit of I/O for the block layer and lower layers (ie drivers and
  24  * stacking drivers)
  25  */
  26 struct bio {
  27         struct bio              *bi_next;       /* request queue link */
  28         struct block_device     *bi_bdev;
  29         int                     bi_error;
  30         unsigned int            bi_opf;         /* bottom bits req flags,
  31                                                  * top bits REQ_OP. Use
  32                                                  * accessors.
  33                                                  */
  34         unsigned short          bi_flags;       /* status, command, etc */
  35         unsigned short          bi_ioprio;
  36
  37         struct bvec_iter        bi_iter;
  38
  39         /* Number of segments in this BIO after
  40          * physical address coalescing is performed.
  41          */
  42         unsigned int            bi_phys_segments;
  43
  44         /*
  45          * To keep track of the max segment size, we account for the
  46          * sizes of the first and last mergeable segments in this bio.
  47          */
  48         unsigned int            bi_seg_front_size;
  49         unsigned int            bi_seg_back_size;
  50
  51         atomic_t                __bi_remaining;
  52
  53         bio_end_io_t            *bi_end_io;
  54
  55         void                    *bi_private;
  56 #ifdef CONFIG_BLK_CGROUP
  57         /*
  58          * Optional ioc and css associated with this bio.  Put on bio
  59          * release.  Read comment on top of bio_associate_current().
  60          */
  61         struct io_context       *bi_ioc;
  62         struct cgroup_subsys_state *bi_css;
  63 #endif
  64         union {
  65 #if defined(CONFIG_BLK_DEV_INTEGRITY)
  66                 struct bio_integrity_payload *bi_integrity; /* data integrity */
  67 #endif
  68         };
  69
  70         unsigned short          bi_vcnt;        /* how many bio_vec's */
  71
  72         /*
  73          * Everything starting with bi_max_vecs will be preserved by bio_reset()
  74          */
  75
  76         unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
  77
  78         atomic_t                __bi_cnt;       /* pin count */
  79
  80         struct bio_vec          *bi_io_vec;     /* the actual vec list */
  81
  82         struct bio_set          *bi_pool;
  83
  84         /*
  85          * We can inline a number of vecs at the end of the bio, to avoid
  86          * double allocations for a small number of bio_vecs. This member
  87          * MUST obviously be kept at the very end of the bio.
  88          */
  89         struct bio_vec          bi_inline_vecs[0];
  90 };
  91
  92 #define BIO_OP_SHIFT    (8 * sizeof(unsigned int) - REQ_OP_BITS)
  93 #define bio_op(bio)     ((bio)->bi_opf >> BIO_OP_SHIFT)
  94
  95 #define bio_set_op_attrs(bio, op, op_flags) do {                \
  96         WARN_ON(op >= (1 << REQ_OP_BITS));                      \
  97         (bio)->bi_opf &= ((1 << BIO_OP_SHIFT) - 1);             \
  98         (bio)->bi_opf |= ((unsigned int) (op) << BIO_OP_SHIFT); \
  99         (bio)->bi_opf |= op_flags;                              \
 100 } while (0)
 101
 102 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
 103
 104 /*
 105  * bio flags
 106  */
 107 #define BIO_SEG_VALID   1       /* bi_phys_segments valid */
 108 #define BIO_CLONED      2       /* doesn't own data */
 109 #define BIO_BOUNCED     3       /* bio is a bounce bio */
 110 #define BIO_USER_MAPPED 4       /* contains user pages */
 111 #define BIO_NULL_MAPPED 5       /* contains invalid user pages */
 112 #define BIO_QUIET       6       /* Make BIO Quiet */
 113 #define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
 114 #define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
 115
 116 /*
 117  * Flags starting here get preserved by bio_reset() - this includes
 118  * BVEC_POOL_IDX()
 119  */
 120 #define BIO_RESET_BITS  10
 121
 122 /*
 123  * We support 6 different bvec pools, the last one is magic in that it
 124  * is backed by a mempool.
 125  */
 126 #define BVEC_POOL_NR            6
 127 #define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)
 128
 129 /*
 130  * Top 4 bits of bio flags indicate the pool the bvecs came from.  We add
 131  * 1 to the actual index so that 0 indicates that there are no bvecs to be
 132  * freed.
 133  */
 134 #define BVEC_POOL_BITS          (4)
 135 #define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
 136 #define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
 137
 138 #endif /* CONFIG_BLOCK */
 139
 140 /*
 141  * Request flags.  For use in the cmd_flags field of struct request, and in
 142  * bi_opf of struct bio.  Note that some flags are only valid in either one.
 143  */
 144 enum rq_flag_bits {
 145         /* common flags */
 146         __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
 147         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
 148         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
 149
 150         __REQ_SYNC,             /* request is sync (sync write or read) */
 151         __REQ_META,             /* metadata io request */
 152         __REQ_PRIO,             /* boost priority in cfq */
 153
 154         __REQ_NOIDLE,           /* don't anticipate more IO after this one */
 155         __REQ_INTEGRITY,        /* I/O includes block integrity payload */
 156         __REQ_FUA,              /* forced unit access */
 157         __REQ_PREFLUSH,         /* request for cache flush */
 158
 159         /* bio only flags */
 160         __REQ_RAHEAD,           /* read ahead, can fail anytime */
 161         __REQ_THROTTLED,        /* This bio has already been subjected to
 162                                  * throttling rules. Don't do it again. */
 163
 164         /* request only flags */
 165         __REQ_SORTED,           /* elevator knows about this request */
 166         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 167         __REQ_NOMERGE,          /* don't touch this for merging */
 168         __REQ_STARTED,          /* drive already may have started this one */
 169         __REQ_DONTPREP,         /* don't call prep for this one */
 170         __REQ_QUEUED,           /* uses queueing */
 171         __REQ_ELVPRIV,          /* elevator private data attached */
 172         __REQ_FAILED,           /* set if the request failed */
 173         __REQ_QUIET,            /* don't worry about errors */
 174         __REQ_PREEMPT,          /* set for "ide_preempt" requests and also
 175                                    for requests for which the SCSI "quiesce"
 176                                    state must be ignored. */
 177         __REQ_ALLOCED,          /* request came from our alloc pool */
 178         __REQ_COPY_USER,        /* contains copies of user pages */
 179         __REQ_FLUSH_SEQ,        /* request for flush sequence */
 180         __REQ_IO_STAT,          /* account I/O stat */
 181         __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 182         __REQ_PM,               /* runtime pm request */
 183         __REQ_HASHED,           /* on IO scheduler merge hash */
 184         __REQ_MQ_INFLIGHT,      /* track inflight for MQ */
 185         __REQ_NR_BITS,          /* stops here */
 186 };
 187
 188 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
 189 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
 190 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
 191 #define REQ_SYNC                (1ULL << __REQ_SYNC)
 192 #define REQ_META                (1ULL << __REQ_META)
 193 #define REQ_PRIO                (1ULL << __REQ_PRIO)
 194 #define REQ_NOIDLE              (1ULL << __REQ_NOIDLE)
 195 #define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
 196
 197 #define REQ_FAILFAST_MASK \
 198         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 199 #define REQ_COMMON_MASK \
 200         (REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | REQ_NOIDLE | \
 201          REQ_PREFLUSH | REQ_FUA | REQ_INTEGRITY | REQ_NOMERGE)
 202 #define REQ_CLONE_MASK          REQ_COMMON_MASK
 203
 204 /* This mask is used for both bio and request merge checking */
 205 #define REQ_NOMERGE_FLAGS \
 206         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_PREFLUSH | REQ_FUA | REQ_FLUSH_SEQ)
 207
 208 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
 209 #define REQ_THROTTLED           (1ULL << __REQ_THROTTLED)
 210
 211 #define REQ_SORTED              (1ULL << __REQ_SORTED)
 212 #define REQ_SOFTBARRIER         (1ULL << __REQ_SOFTBARRIER)
 213 #define REQ_FUA                 (1ULL << __REQ_FUA)
 214 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
 215 #define REQ_STARTED             (1ULL << __REQ_STARTED)
 216 #define REQ_DONTPREP            (1ULL << __REQ_DONTPREP)
 217 #define REQ_QUEUED              (1ULL << __REQ_QUEUED)
 218 #define REQ_ELVPRIV             (1ULL << __REQ_ELVPRIV)
 219 #define REQ_FAILED              (1ULL << __REQ_FAILED)
 220 #define REQ_QUIET               (1ULL << __REQ_QUIET)
 221 #define REQ_PREEMPT             (1ULL << __REQ_PREEMPT)
 222 #define REQ_ALLOCED             (1ULL << __REQ_ALLOCED)
 223 #define REQ_COPY_USER           (1ULL << __REQ_COPY_USER)
 224 #define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
 225 #define REQ_FLUSH_SEQ           (1ULL << __REQ_FLUSH_SEQ)
 226 #define REQ_IO_STAT             (1ULL << __REQ_IO_STAT)
 227 #define REQ_MIXED_MERGE         (1ULL << __REQ_MIXED_MERGE)
 228 #define REQ_PM                  (1ULL << __REQ_PM)
 229 #define REQ_HASHED              (1ULL << __REQ_HASHED)
 230 #define REQ_MQ_INFLIGHT         (1ULL << __REQ_MQ_INFLIGHT)
 231
 232 enum req_op {
 233         REQ_OP_READ,
 234         REQ_OP_WRITE,
 235         REQ_OP_DISCARD,         /* request to discard sectors */
 236         REQ_OP_SECURE_ERASE,    /* request to securely erase sectors */
 237         REQ_OP_WRITE_SAME,      /* write same block many times */
 238         REQ_OP_FLUSH,           /* request for cache flush */
 239 };
 240
 241 #define REQ_OP_BITS 3
 242
 243 typedef unsigned int blk_qc_t;
 244 #define BLK_QC_T_NONE   -1U
 245 #define BLK_QC_T_SHIFT  16
 246
 247 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 248 {
 249         return cookie != BLK_QC_T_NONE;
 250 }
 251
 252 static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num)
 253 {
 254         return tag | (queue_num << BLK_QC_T_SHIFT);
 255 }
 256
 257 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 258 {
 259         return cookie >> BLK_QC_T_SHIFT;
 260 }
 261
 262 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
 263 {
 264         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
 265 }
 266
 267 #endif /* __LINUX_BLK_TYPES_H */