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      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 typedef void (bio_end_io_t) (struct bio *, int);
     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 /*
     30  * main unit of I/O for the block layer and lower layers (ie drivers and
     31  * stacking drivers)
     32  */
     33 struct bio {
     34 	sector_t		bi_sector;	/* device address in 512 byte
     35 						   sectors */
     36 	struct bio		*bi_next;	/* request queue link */
     37 	struct block_device	*bi_bdev;
     38 	unsigned long		bi_flags;	/* status, command, etc */
     39 	unsigned long		bi_rw;		/* bottom bits READ/WRITE,
     40 						 * top bits priority
     41 						 */
     42 
     43 	unsigned short		bi_vcnt;	/* how many bio_vec's */
     44 	unsigned short		bi_idx;		/* current index into bvl_vec */
     45 
     46 	/* Number of segments in this BIO after
     47 	 * physical address coalescing is performed.
     48 	 */
     49 	unsigned int		bi_phys_segments;
     50 
     51 	unsigned int		bi_size;	/* residual I/O count */
     52 
     53 	/*
     54 	 * To keep track of the max segment size, we account for the
     55 	 * sizes of the first and last mergeable segments in this bio.
     56 	 */
     57 	unsigned int		bi_seg_front_size;
     58 	unsigned int		bi_seg_back_size;
     59 
     60 	unsigned int		bi_max_vecs;	/* max bvl_vecs we can hold */
     61 
     62 	atomic_t		bi_cnt;		/* pin count */
     63 
     64 	struct bio_vec		*bi_io_vec;	/* the actual vec list */
     65 
     66 	bio_end_io_t		*bi_end_io;
     67 
     68 	void			*bi_private;
     69 #if defined(CONFIG_BLK_DEV_INTEGRITY)
     70 	struct bio_integrity_payload *bi_integrity;  /* data integrity */
     71 #endif
     72 
     73 	bio_destructor_t	*bi_destructor;	/* destructor */
     74 
     75 	/*
     76 	 * We can __inline__ a number of vecs at the end of the bio, to avoid
     77 	 * double allocations for a small number of bio_vecs. This member
     78 	 * MUST obviously be kept at the very end of the bio.
     79 	 */
     80 	struct bio_vec		bi_inline_vecs[0];
     81 };
     82 
     83 /*
     84  * bio flags
     85  */
     86 #define BIO_UPTODATE	0	/* ok after I/O completion */
     87 #define BIO_RW_BLOCK	1	/* RW_AHEAD set, and read/write would block */
     88 #define BIO_EOF		2	/* out-out-bounds error */
     89 #define BIO_SEG_VALID	3	/* bi_phys_segments valid */
     90 #define BIO_CLONED	4	/* doesn't own data */
     91 #define BIO_BOUNCED	5	/* bio is a bounce bio */
     92 #define BIO_USER_MAPPED 6	/* contains user pages */
     93 #define BIO_EOPNOTSUPP	7	/* not supported */
     94 #define BIO_NULL_MAPPED 8	/* contains invalid user pages */
     95 #define BIO_FS_INTEGRITY 9	/* fs owns integrity data, not block layer */
     96 #define BIO_QUIET	10	/* Make BIO Quiet */
     97 #define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */
     98 #define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))
     99 
    100 /*
    101  * top 4 bits of bio flags indicate the pool this bio came from
    102  */
    103 #define BIO_POOL_BITS		(4)
    104 #define BIO_POOL_NONE		((1UL << BIO_POOL_BITS) - 1)
    105 #define BIO_POOL_OFFSET		(BITS_PER_LONG - BIO_POOL_BITS)
    106 #define BIO_POOL_MASK		(1UL << BIO_POOL_OFFSET)
    107 #define BIO_POOL_IDX(bio)	((bio)->bi_flags >> BIO_POOL_OFFSET)
    108 
    109 #endif /* CONFIG_BLOCK */
    110 
    111 /*
    112  * Request flags.  For use in the cmd_flags field of struct request, and in
    113  * bi_rw of struct bio.  Note that some flags are only valid in either one.
    114  */
    115 enum rq_flag_bits {
    116 	/* common flags */
    117 	__REQ_WRITE,		/* not set, read. set, write */
    118 	__REQ_FAILFAST_DEV,	/* no driver retries of device errors */
    119 	__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
    120 	__REQ_FAILFAST_DRIVER,	/* no driver retries of driver errors */
    121 
    122 	__REQ_SYNC,		/* request is sync (sync write or read) */
    123 	__REQ_META,		/* metadata io request */
    124 	__REQ_PRIO,		/* boost priority in cfq */
    125 	__REQ_DISCARD,		/* request to discard sectors */
    126 	__REQ_SECURE,		/* secure discard (used with __REQ_DISCARD) */
    127 
    128 	__REQ_NOIDLE,		/* don't anticipate more IO after this one */
    129 	__REQ_FUA,		/* forced unit access */
    130 	__REQ_FLUSH,		/* request for cache flush */
    131 
    132 	/* bio only flags */
    133 	__REQ_RAHEAD,		/* read ahead, can fail anytime */
    134 	__REQ_THROTTLED,	/* This bio has already been subjected to
    135 				 * throttling rules. Don't do it again. */
    136 
    137 	/* request only flags */
    138 	__REQ_SORTED,		/* elevator knows about this request */
    139 	__REQ_SOFTBARRIER,	/* may not be passed by ioscheduler */
    140 	__REQ_NOMERGE,		/* don't touch this for merging */
    141 	__REQ_STARTED,		/* drive already may have started this one */
    142 	__REQ_DONTPREP,		/* don't call prep for this one */
    143 	__REQ_QUEUED,		/* uses queueing */
    144 	__REQ_ELVPRIV,		/* elevator private data attached */
    145 	__REQ_FAILED,		/* set if the request failed */
    146 	__REQ_QUIET,		/* don't worry about errors */
    147 	__REQ_PREEMPT,		/* set for "ide_preempt" requests */
    148 	__REQ_ALLOCED,		/* request came from our alloc pool */
    149 	__REQ_COPY_USER,	/* contains copies of user pages */
    150 	__REQ_FLUSH_SEQ,	/* request for flush sequence */
    151 	__REQ_IO_STAT,		/* account I/O stat */
    152 	__REQ_MIXED_MERGE,	/* merge of different types, fail separately */
    153 	__REQ_NR_BITS,		/* stops here */
    154 };
    155 
    156 #define REQ_WRITE		(1 << __REQ_WRITE)
    157 #define REQ_FAILFAST_DEV	(1 << __REQ_FAILFAST_DEV)
    158 #define REQ_FAILFAST_TRANSPORT	(1 << __REQ_FAILFAST_TRANSPORT)
    159 #define REQ_FAILFAST_DRIVER	(1 << __REQ_FAILFAST_DRIVER)
    160 #define REQ_SYNC		(1 << __REQ_SYNC)
    161 #define REQ_META		(1 << __REQ_META)
    162 #define REQ_PRIO		(1 << __REQ_PRIO)
    163 #define REQ_DISCARD		(1 << __REQ_DISCARD)
    164 #define REQ_NOIDLE		(1 << __REQ_NOIDLE)
    165 
    166 #define REQ_FAILFAST_MASK \
    167 	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
    168 #define REQ_COMMON_MASK \
    169 	(REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
    170 	 REQ_DISCARD | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
    171 #define REQ_CLONE_MASK		REQ_COMMON_MASK
    172 
    173 #define REQ_RAHEAD		(1 << __REQ_RAHEAD)
    174 #define REQ_THROTTLED		(1 << __REQ_THROTTLED)
    175 
    176 #define REQ_SORTED		(1 << __REQ_SORTED)
    177 #define REQ_SOFTBARRIER		(1 << __REQ_SOFTBARRIER)
    178 #define REQ_FUA			(1 << __REQ_FUA)
    179 #define REQ_NOMERGE		(1 << __REQ_NOMERGE)
    180 #define REQ_STARTED		(1 << __REQ_STARTED)
    181 #define REQ_DONTPREP		(1 << __REQ_DONTPREP)
    182 #define REQ_QUEUED		(1 << __REQ_QUEUED)
    183 #define REQ_ELVPRIV		(1 << __REQ_ELVPRIV)
    184 #define REQ_FAILED		(1 << __REQ_FAILED)
    185 #define REQ_QUIET		(1 << __REQ_QUIET)
    186 #define REQ_PREEMPT		(1 << __REQ_PREEMPT)
    187 #define REQ_ALLOCED		(1 << __REQ_ALLOCED)
    188 #define REQ_COPY_USER		(1 << __REQ_COPY_USER)
    189 #define REQ_FLUSH		(1 << __REQ_FLUSH)
    190 #define REQ_FLUSH_SEQ		(1 << __REQ_FLUSH_SEQ)
    191 #define REQ_IO_STAT		(1 << __REQ_IO_STAT)
    192 #define REQ_MIXED_MERGE		(1 << __REQ_MIXED_MERGE)
    193 #define REQ_SECURE		(1 << __REQ_SECURE)
    194 
    195 #endif /* __LINUX_BLK_TYPES_H */
    196