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blk_types.h
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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 struct io_context;
18 struct cgroup_subsys_state;
19 typedef void (bio_end_io_t) (struct bio *, int);
20 typedef void (bio_destructor_t) (struct bio *);
21 
22 /*
23  * was unsigned short, but we might as well be ready for > 64kB I/O pages
24  */
25 struct bio_vec {
26  struct page *bv_page;
27  unsigned int bv_len;
28  unsigned int bv_offset;
29 };
30 
31 /*
32  * main unit of I/O for the block layer and lower layers (ie drivers and
33  * stacking drivers)
34  */
35 struct bio {
36  sector_t bi_sector; /* device address in 512 byte
37  sectors */
38  struct bio *bi_next; /* request queue link */
39  struct block_device *bi_bdev;
40  unsigned long bi_flags; /* status, command, etc */
41  unsigned long bi_rw; /* bottom bits READ/WRITE,
42  * top bits priority
43  */
44 
45  unsigned short bi_vcnt; /* how many bio_vec's */
46  unsigned short bi_idx; /* current index into bvl_vec */
47 
48  /* Number of segments in this BIO after
49  * physical address coalescing is performed.
50  */
51  unsigned int bi_phys_segments;
52 
53  unsigned int bi_size; /* residual I/O count */
54 
55  /*
56  * To keep track of the max segment size, we account for the
57  * sizes of the first and last mergeable segments in this bio.
58  */
59  unsigned int bi_seg_front_size;
60  unsigned int bi_seg_back_size;
61 
62  bio_end_io_t *bi_end_io;
63 
64  void *bi_private;
65 #ifdef CONFIG_BLK_CGROUP
66  /*
67  * Optional ioc and css associated with this bio. Put on bio
68  * release. Read comment on top of bio_associate_current().
69  */
70  struct io_context *bi_ioc;
71  struct cgroup_subsys_state *bi_css;
72 #endif
73 #if defined(CONFIG_BLK_DEV_INTEGRITY)
74  struct bio_integrity_payload *bi_integrity; /* data integrity */
75 #endif
76 
77  /*
78  * Everything starting with bi_max_vecs will be preserved by bio_reset()
79  */
80 
81  unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
82 
83  atomic_t bi_cnt; /* pin count */
84 
85  struct bio_vec *bi_io_vec; /* the actual vec list */
86 
87  struct bio_set *bi_pool;
88 
89  /*
90  * We can inline a number of vecs at the end of the bio, to avoid
91  * double allocations for a small number of bio_vecs. This member
92  * MUST obviously be kept at the very end of the bio.
93  */
94  struct bio_vec bi_inline_vecs[0];
95 };
96 
97 #define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs)
98 
99 /*
100  * bio flags
101  */
102 #define BIO_UPTODATE 0 /* ok after I/O completion */
103 #define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */
104 #define BIO_EOF 2 /* out-out-bounds error */
105 #define BIO_SEG_VALID 3 /* bi_phys_segments valid */
106 #define BIO_CLONED 4 /* doesn't own data */
107 #define BIO_BOUNCED 5 /* bio is a bounce bio */
108 #define BIO_USER_MAPPED 6 /* contains user pages */
109 #define BIO_EOPNOTSUPP 7 /* not supported */
110 #define BIO_NULL_MAPPED 8 /* contains invalid user pages */
111 #define BIO_FS_INTEGRITY 9 /* fs owns integrity data, not block layer */
112 #define BIO_QUIET 10 /* Make BIO Quiet */
113 #define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */
114 
115 /*
116  * Flags starting here get preserved by bio_reset() - this includes
117  * BIO_POOL_IDX()
118  */
119 #define BIO_RESET_BITS 12
120 
121 #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag)))
122 
123 /*
124  * top 4 bits of bio flags indicate the pool this bio came from
125  */
126 #define BIO_POOL_BITS (4)
127 #define BIO_POOL_NONE ((1UL << BIO_POOL_BITS) - 1)
128 #define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS)
129 #define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET)
130 #define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)
131 
132 #endif /* CONFIG_BLOCK */
133 
134 /*
135  * Request flags. For use in the cmd_flags field of struct request, and in
136  * bi_rw of struct bio. Note that some flags are only valid in either one.
137  */
139  /* common flags */
140  __REQ_WRITE, /* not set, read. set, write */
141  __REQ_FAILFAST_DEV, /* no driver retries of device errors */
142  __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
143  __REQ_FAILFAST_DRIVER, /* no driver retries of driver errors */
144 
145  __REQ_SYNC, /* request is sync (sync write or read) */
146  __REQ_META, /* metadata io request */
147  __REQ_PRIO, /* boost priority in cfq */
148  __REQ_DISCARD, /* request to discard sectors */
149  __REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */
150  __REQ_WRITE_SAME, /* write same block many times */
151 
152  __REQ_NOIDLE, /* don't anticipate more IO after this one */
153  __REQ_FUA, /* forced unit access */
154  __REQ_FLUSH, /* request for cache flush */
155 
156  /* bio only flags */
157  __REQ_RAHEAD, /* read ahead, can fail anytime */
158  __REQ_THROTTLED, /* This bio has already been subjected to
159  * throttling rules. Don't do it again. */
160 
161  /* request only flags */
162  __REQ_SORTED, /* elevator knows about this request */
163  __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
164  __REQ_NOMERGE, /* don't touch this for merging */
165  __REQ_STARTED, /* drive already may have started this one */
166  __REQ_DONTPREP, /* don't call prep for this one */
167  __REQ_QUEUED, /* uses queueing */
168  __REQ_ELVPRIV, /* elevator private data attached */
169  __REQ_FAILED, /* set if the request failed */
170  __REQ_QUIET, /* don't worry about errors */
171  __REQ_PREEMPT, /* set for "ide_preempt" requests */
172  __REQ_ALLOCED, /* request came from our alloc pool */
173  __REQ_COPY_USER, /* contains copies of user pages */
174  __REQ_FLUSH_SEQ, /* request for flush sequence */
175  __REQ_IO_STAT, /* account I/O stat */
176  __REQ_MIXED_MERGE, /* merge of different types, fail separately */
177  __REQ_KERNEL, /* direct IO to kernel pages */
178  __REQ_NR_BITS, /* stops here */
179 };
180 
181 #define REQ_WRITE (1 << __REQ_WRITE)
182 #define REQ_FAILFAST_DEV (1 << __REQ_FAILFAST_DEV)
183 #define REQ_FAILFAST_TRANSPORT (1 << __REQ_FAILFAST_TRANSPORT)
184 #define REQ_FAILFAST_DRIVER (1 << __REQ_FAILFAST_DRIVER)
185 #define REQ_SYNC (1 << __REQ_SYNC)
186 #define REQ_META (1 << __REQ_META)
187 #define REQ_PRIO (1 << __REQ_PRIO)
188 #define REQ_DISCARD (1 << __REQ_DISCARD)
189 #define REQ_WRITE_SAME (1 << __REQ_WRITE_SAME)
190 #define REQ_NOIDLE (1 << __REQ_NOIDLE)
191 
192 #define REQ_FAILFAST_MASK \
193  (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
194 #define REQ_COMMON_MASK \
195  (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
196  REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
197  REQ_SECURE)
198 #define REQ_CLONE_MASK REQ_COMMON_MASK
199 
200 /* This mask is used for both bio and request merge checking */
201 #define REQ_NOMERGE_FLAGS \
202  (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
203 
204 #define REQ_RAHEAD (1 << __REQ_RAHEAD)
205 #define REQ_THROTTLED (1 << __REQ_THROTTLED)
206 
207 #define REQ_SORTED (1 << __REQ_SORTED)
208 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
209 #define REQ_FUA (1 << __REQ_FUA)
210 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
211 #define REQ_STARTED (1 << __REQ_STARTED)
212 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
213 #define REQ_QUEUED (1 << __REQ_QUEUED)
214 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
215 #define REQ_FAILED (1 << __REQ_FAILED)
216 #define REQ_QUIET (1 << __REQ_QUIET)
217 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
218 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
219 #define REQ_COPY_USER (1 << __REQ_COPY_USER)
220 #define REQ_FLUSH (1 << __REQ_FLUSH)
221 #define REQ_FLUSH_SEQ (1 << __REQ_FLUSH_SEQ)
222 #define REQ_IO_STAT (1 << __REQ_IO_STAT)
223 #define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
224 #define REQ_SECURE (1 << __REQ_SECURE)
225 #define REQ_KERNEL (1 << __REQ_KERNEL)
226 
227 #endif /* __LINUX_BLK_TYPES_H */