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![Christoph Hellwig](/assets/img/avatar_default.png)
Currently the block layer op_is_write, bio_data_dir and rq_data_dir helper treat every operation that is not a READ as a data out operation. This worked surprisingly long, but the new REQ_OP_ZONE_REPORT operation actually adds a second operation that reads data from the device. Surprisingly nothing critical relied on this direction, but this might be a good opportunity to properly fix this issue up. We take a little inspiration and use the least significant bit of the operation number to encode the data direction, which just requires us to renumber the operations to fix this scheme. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
248 lines
6.7 KiB
C
248 lines
6.7 KiB
C
/*
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* Block data types and constants. Directly include this file only to
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* break include dependency loop.
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*/
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#ifndef __LINUX_BLK_TYPES_H
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#define __LINUX_BLK_TYPES_H
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#include <linux/types.h>
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#include <linux/bvec.h>
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struct bio_set;
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struct bio;
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struct bio_integrity_payload;
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struct page;
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struct block_device;
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struct io_context;
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struct cgroup_subsys_state;
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typedef void (bio_end_io_t) (struct bio *);
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#ifdef CONFIG_BLOCK
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/*
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* main unit of I/O for the block layer and lower layers (ie drivers and
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* stacking drivers)
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*/
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struct bio {
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struct bio *bi_next; /* request queue link */
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struct block_device *bi_bdev;
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int bi_error;
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unsigned int bi_opf; /* bottom bits req flags,
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* top bits REQ_OP. Use
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* accessors.
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*/
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unsigned short bi_flags; /* status, command, etc */
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unsigned short bi_ioprio;
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struct bvec_iter bi_iter;
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/* Number of segments in this BIO after
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* physical address coalescing is performed.
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*/
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unsigned int bi_phys_segments;
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/*
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* To keep track of the max segment size, we account for the
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* sizes of the first and last mergeable segments in this bio.
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*/
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unsigned int bi_seg_front_size;
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unsigned int bi_seg_back_size;
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atomic_t __bi_remaining;
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bio_end_io_t *bi_end_io;
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void *bi_private;
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#ifdef CONFIG_BLK_CGROUP
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/*
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* Optional ioc and css associated with this bio. Put on bio
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* release. Read comment on top of bio_associate_current().
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*/
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struct io_context *bi_ioc;
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struct cgroup_subsys_state *bi_css;
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#endif
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union {
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#if defined(CONFIG_BLK_DEV_INTEGRITY)
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struct bio_integrity_payload *bi_integrity; /* data integrity */
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#endif
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};
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unsigned short bi_vcnt; /* how many bio_vec's */
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/*
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* Everything starting with bi_max_vecs will be preserved by bio_reset()
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*/
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unsigned short bi_max_vecs; /* max bvl_vecs we can hold */
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atomic_t __bi_cnt; /* pin count */
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struct bio_vec *bi_io_vec; /* the actual vec list */
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struct bio_set *bi_pool;
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/*
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* We can inline a number of vecs at the end of the bio, to avoid
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* double allocations for a small number of bio_vecs. This member
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* MUST obviously be kept at the very end of the bio.
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*/
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struct bio_vec bi_inline_vecs[0];
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};
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#define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs)
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/*
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* bio flags
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*/
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#define BIO_SEG_VALID 1 /* bi_phys_segments valid */
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#define BIO_CLONED 2 /* doesn't own data */
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#define BIO_BOUNCED 3 /* bio is a bounce bio */
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#define BIO_USER_MAPPED 4 /* contains user pages */
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#define BIO_NULL_MAPPED 5 /* contains invalid user pages */
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#define BIO_QUIET 6 /* Make BIO Quiet */
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#define BIO_CHAIN 7 /* chained bio, ->bi_remaining in effect */
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#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */
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#define BIO_THROTTLED 9 /* This bio has already been subjected to
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* throttling rules. Don't do it again. */
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/*
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* Flags starting here get preserved by bio_reset() - this includes
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* BVEC_POOL_IDX()
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*/
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#define BIO_RESET_BITS 10
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/*
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* We support 6 different bvec pools, the last one is magic in that it
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* is backed by a mempool.
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*/
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#define BVEC_POOL_NR 6
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#define BVEC_POOL_MAX (BVEC_POOL_NR - 1)
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/*
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* Top 4 bits of bio flags indicate the pool the bvecs came from. We add
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* 1 to the actual index so that 0 indicates that there are no bvecs to be
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* freed.
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*/
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#define BVEC_POOL_BITS (4)
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#define BVEC_POOL_OFFSET (16 - BVEC_POOL_BITS)
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#define BVEC_POOL_IDX(bio) ((bio)->bi_flags >> BVEC_POOL_OFFSET)
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#endif /* CONFIG_BLOCK */
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/*
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* Operations and flags common to the bio and request structures.
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* We use 8 bits for encoding the operation, and the remaining 24 for flags.
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*
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* The least significant bit of the operation number indicates the data
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* transfer direction:
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*
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* - if the least significant bit is set transfers are TO the device
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* - if the least significant bit is not set transfers are FROM the device
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*
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* If a operation does not transfer data the least significant bit has no
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* meaning.
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*/
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#define REQ_OP_BITS 8
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#define REQ_OP_MASK ((1 << REQ_OP_BITS) - 1)
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#define REQ_FLAG_BITS 24
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enum req_opf {
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/* read sectors from the device */
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REQ_OP_READ = 0,
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/* write sectors to the device */
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REQ_OP_WRITE = 1,
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/* flush the volatile write cache */
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REQ_OP_FLUSH = 2,
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/* discard sectors */
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REQ_OP_DISCARD = 3,
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/* get zone information */
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REQ_OP_ZONE_REPORT = 4,
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/* securely erase sectors */
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REQ_OP_SECURE_ERASE = 5,
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/* seset a zone write pointer */
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REQ_OP_ZONE_RESET = 6,
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/* write the same sector many times */
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REQ_OP_WRITE_SAME = 7,
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REQ_OP_LAST,
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};
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enum req_flag_bits {
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__REQ_FAILFAST_DEV = /* no driver retries of device errors */
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REQ_OP_BITS,
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__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
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__REQ_FAILFAST_DRIVER, /* no driver retries of driver errors */
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__REQ_SYNC, /* request is sync (sync write or read) */
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__REQ_META, /* metadata io request */
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__REQ_PRIO, /* boost priority in cfq */
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__REQ_NOMERGE, /* don't touch this for merging */
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__REQ_NOIDLE, /* don't anticipate more IO after this one */
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__REQ_INTEGRITY, /* I/O includes block integrity payload */
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__REQ_FUA, /* forced unit access */
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__REQ_PREFLUSH, /* request for cache flush */
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__REQ_RAHEAD, /* read ahead, can fail anytime */
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__REQ_NR_BITS, /* stops here */
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};
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#define REQ_FAILFAST_DEV (1ULL << __REQ_FAILFAST_DEV)
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#define REQ_FAILFAST_TRANSPORT (1ULL << __REQ_FAILFAST_TRANSPORT)
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#define REQ_FAILFAST_DRIVER (1ULL << __REQ_FAILFAST_DRIVER)
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#define REQ_SYNC (1ULL << __REQ_SYNC)
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#define REQ_META (1ULL << __REQ_META)
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#define REQ_PRIO (1ULL << __REQ_PRIO)
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#define REQ_NOMERGE (1ULL << __REQ_NOMERGE)
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#define REQ_NOIDLE (1ULL << __REQ_NOIDLE)
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#define REQ_INTEGRITY (1ULL << __REQ_INTEGRITY)
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#define REQ_FUA (1ULL << __REQ_FUA)
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#define REQ_PREFLUSH (1ULL << __REQ_PREFLUSH)
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#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
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#define REQ_FAILFAST_MASK \
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(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
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#define REQ_NOMERGE_FLAGS \
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(REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
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#define bio_op(bio) \
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((bio)->bi_opf & REQ_OP_MASK)
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#define req_op(req) \
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((req)->cmd_flags & REQ_OP_MASK)
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/* obsolete, don't use in new code */
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#define bio_set_op_attrs(bio, op, op_flags) \
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((bio)->bi_opf |= (op | op_flags))
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static inline bool op_is_write(unsigned int op)
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{
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return (op & 1);
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}
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static inline bool op_is_sync(unsigned int op)
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{
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return (op & REQ_OP_MASK) == REQ_OP_READ || (op & REQ_SYNC);
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}
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typedef unsigned int blk_qc_t;
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#define BLK_QC_T_NONE -1U
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#define BLK_QC_T_SHIFT 16
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static inline bool blk_qc_t_valid(blk_qc_t cookie)
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{
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return cookie != BLK_QC_T_NONE;
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}
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static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num)
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{
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return tag | (queue_num << BLK_QC_T_SHIFT);
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}
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static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
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{
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return cookie >> BLK_QC_T_SHIFT;
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}
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static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
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{
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return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
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}
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#endif /* __LINUX_BLK_TYPES_H */
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