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TOMOYO Linux Cross Reference
Linux/include/linux/blk_types.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 /*
  3  * Block data types and constants.  Directly include this file only to
  4  * break include dependency loop.
  5  */
  6 #ifndef __LINUX_BLK_TYPES_H
  7 #define __LINUX_BLK_TYPES_H
  8 
  9 #include <linux/types.h>
 10 #include <linux/bvec.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 *);
 20 
 21 /*
 22  * Block error status values.  See block/blk-core:blk_errors for the details.
 23  * Alpha cannot write a byte atomically, so we need to use 32-bit value.
 24  */
 25 #if defined(CONFIG_ALPHA) && !defined(__alpha_bwx__)
 26 typedef u32 __bitwise blk_status_t;
 27 #else
 28 typedef u8 __bitwise blk_status_t;
 29 #endif
 30 #define BLK_STS_OK 0
 31 #define BLK_STS_NOTSUPP         ((__force blk_status_t)1)
 32 #define BLK_STS_TIMEOUT         ((__force blk_status_t)2)
 33 #define BLK_STS_NOSPC           ((__force blk_status_t)3)
 34 #define BLK_STS_TRANSPORT       ((__force blk_status_t)4)
 35 #define BLK_STS_TARGET          ((__force blk_status_t)5)
 36 #define BLK_STS_NEXUS           ((__force blk_status_t)6)
 37 #define BLK_STS_MEDIUM          ((__force blk_status_t)7)
 38 #define BLK_STS_PROTECTION      ((__force blk_status_t)8)
 39 #define BLK_STS_RESOURCE        ((__force blk_status_t)9)
 40 #define BLK_STS_IOERR           ((__force blk_status_t)10)
 41 
 42 /* hack for device mapper, don't use elsewhere: */
 43 #define BLK_STS_DM_REQUEUE    ((__force blk_status_t)11)
 44 
 45 #define BLK_STS_AGAIN           ((__force blk_status_t)12)
 46 
 47 /*
 48  * BLK_STS_DEV_RESOURCE is returned from the driver to the block layer if
 49  * device related resources are unavailable, but the driver can guarantee
 50  * that the queue will be rerun in the future once resources become
 51  * available again. This is typically the case for device specific
 52  * resources that are consumed for IO. If the driver fails allocating these
 53  * resources, we know that inflight (or pending) IO will free these
 54  * resource upon completion.
 55  *
 56  * This is different from BLK_STS_RESOURCE in that it explicitly references
 57  * a device specific resource. For resources of wider scope, allocation
 58  * failure can happen without having pending IO. This means that we can't
 59  * rely on request completions freeing these resources, as IO may not be in
 60  * flight. Examples of that are kernel memory allocations, DMA mappings, or
 61  * any other system wide resources.
 62  */
 63 #define BLK_STS_DEV_RESOURCE    ((__force blk_status_t)13)
 64 
 65 /**
 66  * blk_path_error - returns true if error may be path related
 67  * @error: status the request was completed with
 68  *
 69  * Description:
 70  *     This classifies block error status into non-retryable errors and ones
 71  *     that may be successful if retried on a failover path.
 72  *
 73  * Return:
 74  *     %false - retrying failover path will not help
 75  *     %true  - may succeed if retried
 76  */
 77 static inline bool blk_path_error(blk_status_t error)
 78 {
 79         switch (error) {
 80         case BLK_STS_NOTSUPP:
 81         case BLK_STS_NOSPC:
 82         case BLK_STS_TARGET:
 83         case BLK_STS_NEXUS:
 84         case BLK_STS_MEDIUM:
 85         case BLK_STS_PROTECTION:
 86                 return false;
 87         }
 88 
 89         /* Anything else could be a path failure, so should be retried */
 90         return true;
 91 }
 92 
 93 struct blk_issue_stat {
 94         u64 stat;
 95 };
 96 
 97 /*
 98  * main unit of I/O for the block layer and lower layers (ie drivers and
 99  * stacking drivers)
100  */
101 struct bio {
102         struct bio              *bi_next;       /* request queue link */
103         struct gendisk          *bi_disk;
104         unsigned int            bi_opf;         /* bottom bits req flags,
105                                                  * top bits REQ_OP. Use
106                                                  * accessors.
107                                                  */
108         unsigned short          bi_flags;       /* status, etc and bvec pool number */
109         unsigned short          bi_ioprio;
110         unsigned short          bi_write_hint;
111         blk_status_t            bi_status;
112         u8                      bi_partno;
113 
114         /* Number of segments in this BIO after
115          * physical address coalescing is performed.
116          */
117         unsigned int            bi_phys_segments;
118 
119         /*
120          * To keep track of the max segment size, we account for the
121          * sizes of the first and last mergeable segments in this bio.
122          */
123         unsigned int            bi_seg_front_size;
124         unsigned int            bi_seg_back_size;
125 
126         struct bvec_iter        bi_iter;
127 
128         atomic_t                __bi_remaining;
129         bio_end_io_t            *bi_end_io;
130 
131         void                    *bi_private;
132 #ifdef CONFIG_BLK_CGROUP
133         /*
134          * Optional ioc and css associated with this bio.  Put on bio
135          * release.  Read comment on top of bio_associate_current().
136          */
137         struct io_context       *bi_ioc;
138         struct cgroup_subsys_state *bi_css;
139 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
140         void                    *bi_cg_private;
141         struct blk_issue_stat   bi_issue_stat;
142 #endif
143 #endif
144         union {
145 #if defined(CONFIG_BLK_DEV_INTEGRITY)
146                 struct bio_integrity_payload *bi_integrity; /* data integrity */
147 #endif
148         };
149 
150         unsigned short          bi_vcnt;        /* how many bio_vec's */
151 
152         /*
153          * Everything starting with bi_max_vecs will be preserved by bio_reset()
154          */
155 
156         unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
157 
158         atomic_t                __bi_cnt;       /* pin count */
159 
160         struct bio_vec          *bi_io_vec;     /* the actual vec list */
161 
162         struct bio_set          *bi_pool;
163 
164         /*
165          * We can inline a number of vecs at the end of the bio, to avoid
166          * double allocations for a small number of bio_vecs. This member
167          * MUST obviously be kept at the very end of the bio.
168          */
169         struct bio_vec          bi_inline_vecs[0];
170 };
171 
172 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
173 
174 /*
175  * bio flags
176  */
177 #define BIO_SEG_VALID   1       /* bi_phys_segments valid */
178 #define BIO_CLONED      2       /* doesn't own data */
179 #define BIO_BOUNCED     3       /* bio is a bounce bio */
180 #define BIO_USER_MAPPED 4       /* contains user pages */
181 #define BIO_NULL_MAPPED 5       /* contains invalid user pages */
182 #define BIO_QUIET       6       /* Make BIO Quiet */
183 #define BIO_CHAIN       7       /* chained bio, ->bi_remaining in effect */
184 #define BIO_REFFED      8       /* bio has elevated ->bi_cnt */
185 #define BIO_THROTTLED   9       /* This bio has already been subjected to
186                                  * throttling rules. Don't do it again. */
187 #define BIO_TRACE_COMPLETION 10 /* bio_endio() should trace the final completion
188                                  * of this bio. */
189 #define BIO_QUEUE_ENTERED 11    /* can use blk_queue_enter_live() */
190 
191 /* See BVEC_POOL_OFFSET below before adding new flags */
192 
193 /*
194  * We support 6 different bvec pools, the last one is magic in that it
195  * is backed by a mempool.
196  */
197 #define BVEC_POOL_NR            6
198 #define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)
199 
200 /*
201  * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
202  * 1 to the actual index so that 0 indicates that there are no bvecs to be
203  * freed.
204  */
205 #define BVEC_POOL_BITS          (3)
206 #define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
207 #define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
208 #if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
209 # error "BVEC_POOL_BITS is too small"
210 #endif
211 
212 /*
213  * Flags starting here get preserved by bio_reset() - this includes
214  * only BVEC_POOL_IDX()
215  */
216 #define BIO_RESET_BITS  BVEC_POOL_OFFSET
217 
218 typedef __u32 __bitwise blk_mq_req_flags_t;
219 
220 /*
221  * Operations and flags common to the bio and request structures.
222  * We use 8 bits for encoding the operation, and the remaining 24 for flags.
223  *
224  * The least significant bit of the operation number indicates the data
225  * transfer direction:
226  *
227  *   - if the least significant bit is set transfers are TO the device
228  *   - if the least significant bit is not set transfers are FROM the device
229  *
230  * If a operation does not transfer data the least significant bit has no
231  * meaning.
232  */
233 #define REQ_OP_BITS     8
234 #define REQ_OP_MASK     ((1 << REQ_OP_BITS) - 1)
235 #define REQ_FLAG_BITS   24
236 
237 enum req_opf {
238         /* read sectors from the device */
239         REQ_OP_READ             = 0,
240         /* write sectors to the device */
241         REQ_OP_WRITE            = 1,
242         /* flush the volatile write cache */
243         REQ_OP_FLUSH            = 2,
244         /* discard sectors */
245         REQ_OP_DISCARD          = 3,
246         /* get zone information */
247         REQ_OP_ZONE_REPORT      = 4,
248         /* securely erase sectors */
249         REQ_OP_SECURE_ERASE     = 5,
250         /* seset a zone write pointer */
251         REQ_OP_ZONE_RESET       = 6,
252         /* write the same sector many times */
253         REQ_OP_WRITE_SAME       = 7,
254         /* write the zero filled sector many times */
255         REQ_OP_WRITE_ZEROES     = 9,
256 
257         /* SCSI passthrough using struct scsi_request */
258         REQ_OP_SCSI_IN          = 32,
259         REQ_OP_SCSI_OUT         = 33,
260         /* Driver private requests */
261         REQ_OP_DRV_IN           = 34,
262         REQ_OP_DRV_OUT          = 35,
263 
264         REQ_OP_LAST,
265 };
266 
267 enum req_flag_bits {
268         __REQ_FAILFAST_DEV =    /* no driver retries of device errors */
269                 REQ_OP_BITS,
270         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
271         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
272         __REQ_SYNC,             /* request is sync (sync write or read) */
273         __REQ_META,             /* metadata io request */
274         __REQ_PRIO,             /* boost priority in cfq */
275         __REQ_NOMERGE,          /* don't touch this for merging */
276         __REQ_IDLE,             /* anticipate more IO after this one */
277         __REQ_INTEGRITY,        /* I/O includes block integrity payload */
278         __REQ_FUA,              /* forced unit access */
279         __REQ_PREFLUSH,         /* request for cache flush */
280         __REQ_RAHEAD,           /* read ahead, can fail anytime */
281         __REQ_BACKGROUND,       /* background IO */
282         __REQ_NOWAIT,           /* Don't wait if request will block */
283 
284         /* command specific flags for REQ_OP_WRITE_ZEROES: */
285         __REQ_NOUNMAP,          /* do not free blocks when zeroing */
286 
287         /* for driver use */
288         __REQ_DRV,
289 
290         __REQ_NR_BITS,          /* stops here */
291 };
292 
293 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
294 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
295 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
296 #define REQ_SYNC                (1ULL << __REQ_SYNC)
297 #define REQ_META                (1ULL << __REQ_META)
298 #define REQ_PRIO                (1ULL << __REQ_PRIO)
299 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
300 #define REQ_IDLE                (1ULL << __REQ_IDLE)
301 #define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
302 #define REQ_FUA                 (1ULL << __REQ_FUA)
303 #define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
304 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
305 #define REQ_BACKGROUND          (1ULL << __REQ_BACKGROUND)
306 #define REQ_NOWAIT              (1ULL << __REQ_NOWAIT)
307 
308 #define REQ_NOUNMAP             (1ULL << __REQ_NOUNMAP)
309 
310 #define REQ_DRV                 (1ULL << __REQ_DRV)
311 
312 #define REQ_FAILFAST_MASK \
313         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
314 
315 #define REQ_NOMERGE_FLAGS \
316         (REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
317 
318 #define bio_op(bio) \
319         ((bio)->bi_opf & REQ_OP_MASK)
320 #define req_op(req) \
321         ((req)->cmd_flags & REQ_OP_MASK)
322 
323 /* obsolete, don't use in new code */
324 static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
325                 unsigned op_flags)
326 {
327         bio->bi_opf = op | op_flags;
328 }
329 
330 static inline bool op_is_write(unsigned int op)
331 {
332         return (op & 1);
333 }
334 
335 /*
336  * Check if the bio or request is one that needs special treatment in the
337  * flush state machine.
338  */
339 static inline bool op_is_flush(unsigned int op)
340 {
341         return op & (REQ_FUA | REQ_PREFLUSH);
342 }
343 
344 /*
345  * Reads are always treated as synchronous, as are requests with the FUA or
346  * PREFLUSH flag.  Other operations may be marked as synchronous using the
347  * REQ_SYNC flag.
348  */
349 static inline bool op_is_sync(unsigned int op)
350 {
351         return (op & REQ_OP_MASK) == REQ_OP_READ ||
352                 (op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
353 }
354 
355 typedef unsigned int blk_qc_t;
356 #define BLK_QC_T_NONE           -1U
357 #define BLK_QC_T_SHIFT          16
358 #define BLK_QC_T_INTERNAL       (1U << 31)
359 
360 static inline bool blk_qc_t_valid(blk_qc_t cookie)
361 {
362         return cookie != BLK_QC_T_NONE;
363 }
364 
365 static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
366                                        bool internal)
367 {
368         blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
369 
370         if (internal)
371                 ret |= BLK_QC_T_INTERNAL;
372 
373         return ret;
374 }
375 
376 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
377 {
378         return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
379 }
380 
381 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
382 {
383         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
384 }
385 
386 static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
387 {
388         return (cookie & BLK_QC_T_INTERNAL) != 0;
389 }
390 
391 struct blk_rq_stat {
392         u64 mean;
393         u64 min;
394         u64 max;
395         u32 nr_samples;
396         u64 batch;
397 };
398 
399 #endif /* __LINUX_BLK_TYPES_H */
400 

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