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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 #include <linux/ktime.h>
 12 
 13 struct bio_set;
 14 struct bio;
 15 struct bio_integrity_payload;
 16 struct page;
 17 struct block_device;
 18 struct io_context;
 19 struct cgroup_subsys_state;
 20 typedef void (bio_end_io_t) (struct bio *);
 21 
 22 /*
 23  * Block error status values.  See block/blk-core:blk_errors for the details.
 24  * Alpha cannot write a byte atomically, so we need to use 32-bit value.
 25  */
 26 #if defined(CONFIG_ALPHA) && !defined(__alpha_bwx__)
 27 typedef u32 __bitwise blk_status_t;
 28 #else
 29 typedef u8 __bitwise blk_status_t;
 30 #endif
 31 #define BLK_STS_OK 0
 32 #define BLK_STS_NOTSUPP         ((__force blk_status_t)1)
 33 #define BLK_STS_TIMEOUT         ((__force blk_status_t)2)
 34 #define BLK_STS_NOSPC           ((__force blk_status_t)3)
 35 #define BLK_STS_TRANSPORT       ((__force blk_status_t)4)
 36 #define BLK_STS_TARGET          ((__force blk_status_t)5)
 37 #define BLK_STS_NEXUS           ((__force blk_status_t)6)
 38 #define BLK_STS_MEDIUM          ((__force blk_status_t)7)
 39 #define BLK_STS_PROTECTION      ((__force blk_status_t)8)
 40 #define BLK_STS_RESOURCE        ((__force blk_status_t)9)
 41 #define BLK_STS_IOERR           ((__force blk_status_t)10)
 42 
 43 /* hack for device mapper, don't use elsewhere: */
 44 #define BLK_STS_DM_REQUEUE    ((__force blk_status_t)11)
 45 
 46 #define BLK_STS_AGAIN           ((__force blk_status_t)12)
 47 
 48 /*
 49  * BLK_STS_DEV_RESOURCE is returned from the driver to the block layer if
 50  * device related resources are unavailable, but the driver can guarantee
 51  * that the queue will be rerun in the future once resources become
 52  * available again. This is typically the case for device specific
 53  * resources that are consumed for IO. If the driver fails allocating these
 54  * resources, we know that inflight (or pending) IO will free these
 55  * resource upon completion.
 56  *
 57  * This is different from BLK_STS_RESOURCE in that it explicitly references
 58  * a device specific resource. For resources of wider scope, allocation
 59  * failure can happen without having pending IO. This means that we can't
 60  * rely on request completions freeing these resources, as IO may not be in
 61  * flight. Examples of that are kernel memory allocations, DMA mappings, or
 62  * any other system wide resources.
 63  */
 64 #define BLK_STS_DEV_RESOURCE    ((__force blk_status_t)13)
 65 
 66 /**
 67  * blk_path_error - returns true if error may be path related
 68  * @error: status the request was completed with
 69  *
 70  * Description:
 71  *     This classifies block error status into non-retryable errors and ones
 72  *     that may be successful if retried on a failover path.
 73  *
 74  * Return:
 75  *     %false - retrying failover path will not help
 76  *     %true  - may succeed if retried
 77  */
 78 static inline bool blk_path_error(blk_status_t error)
 79 {
 80         switch (error) {
 81         case BLK_STS_NOTSUPP:
 82         case BLK_STS_NOSPC:
 83         case BLK_STS_TARGET:
 84         case BLK_STS_NEXUS:
 85         case BLK_STS_MEDIUM:
 86         case BLK_STS_PROTECTION:
 87                 return false;
 88         }
 89 
 90         /* Anything else could be a path failure, so should be retried */
 91         return true;
 92 }
 93 
 94 /*
 95  * From most significant bit:
 96  * 1 bit: reserved for other usage, see below
 97  * 12 bits: original size of bio
 98  * 51 bits: issue time of bio
 99  */
100 #define BIO_ISSUE_RES_BITS      1
101 #define BIO_ISSUE_SIZE_BITS     12
102 #define BIO_ISSUE_RES_SHIFT     (64 - BIO_ISSUE_RES_BITS)
103 #define BIO_ISSUE_SIZE_SHIFT    (BIO_ISSUE_RES_SHIFT - BIO_ISSUE_SIZE_BITS)
104 #define BIO_ISSUE_TIME_MASK     ((1ULL << BIO_ISSUE_SIZE_SHIFT) - 1)
105 #define BIO_ISSUE_SIZE_MASK     \
106         (((1ULL << BIO_ISSUE_SIZE_BITS) - 1) << BIO_ISSUE_SIZE_SHIFT)
107 #define BIO_ISSUE_RES_MASK      (~((1ULL << BIO_ISSUE_RES_SHIFT) - 1))
108 
109 /* Reserved bit for blk-throtl */
110 #define BIO_ISSUE_THROTL_SKIP_LATENCY (1ULL << 63)
111 
112 struct bio_issue {
113         u64 value;
114 };
115 
116 static inline u64 __bio_issue_time(u64 time)
117 {
118         return time & BIO_ISSUE_TIME_MASK;
119 }
120 
121 static inline u64 bio_issue_time(struct bio_issue *issue)
122 {
123         return __bio_issue_time(issue->value);
124 }
125 
126 static inline sector_t bio_issue_size(struct bio_issue *issue)
127 {
128         return ((issue->value & BIO_ISSUE_SIZE_MASK) >> BIO_ISSUE_SIZE_SHIFT);
129 }
130 
131 static inline void bio_issue_init(struct bio_issue *issue,
132                                        sector_t size)
133 {
134         size &= (1ULL << BIO_ISSUE_SIZE_BITS) - 1;
135         issue->value = ((issue->value & BIO_ISSUE_RES_MASK) |
136                         (ktime_get_ns() & BIO_ISSUE_TIME_MASK) |
137                         ((u64)size << BIO_ISSUE_SIZE_SHIFT));
138 }
139 
140 /*
141  * main unit of I/O for the block layer and lower layers (ie drivers and
142  * stacking drivers)
143  */
144 struct bio {
145         struct bio              *bi_next;       /* request queue link */
146         struct gendisk          *bi_disk;
147         unsigned int            bi_opf;         /* bottom bits req flags,
148                                                  * top bits REQ_OP. Use
149                                                  * accessors.
150                                                  */
151         unsigned short          bi_flags;       /* status, etc and bvec pool number */
152         unsigned short          bi_ioprio;
153         unsigned short          bi_write_hint;
154         blk_status_t            bi_status;
155         u8                      bi_partno;
156 
157         struct bvec_iter        bi_iter;
158 
159         atomic_t                __bi_remaining;
160         bio_end_io_t            *bi_end_io;
161 
162         void                    *bi_private;
163 #ifdef CONFIG_BLK_CGROUP
164         /*
165          * Represents the association of the css and request_queue for the bio.
166          * If a bio goes direct to device, it will not have a blkg as it will
167          * not have a request_queue associated with it.  The reference is put
168          * on release of the bio.
169          */
170         struct blkcg_gq         *bi_blkg;
171         struct bio_issue        bi_issue;
172 #endif
173         union {
174 #if defined(CONFIG_BLK_DEV_INTEGRITY)
175                 struct bio_integrity_payload *bi_integrity; /* data integrity */
176 #endif
177         };
178 
179         unsigned short          bi_vcnt;        /* how many bio_vec's */
180 
181         /*
182          * Everything starting with bi_max_vecs will be preserved by bio_reset()
183          */
184 
185         unsigned short          bi_max_vecs;    /* max bvl_vecs we can hold */
186 
187         atomic_t                __bi_cnt;       /* pin count */
188 
189         struct bio_vec          *bi_io_vec;     /* the actual vec list */
190 
191         struct bio_set          *bi_pool;
192 
193         /*
194          * We can inline a number of vecs at the end of the bio, to avoid
195          * double allocations for a small number of bio_vecs. This member
196          * MUST obviously be kept at the very end of the bio.
197          */
198         struct bio_vec          bi_inline_vecs[0];
199 };
200 
201 #define BIO_RESET_BYTES         offsetof(struct bio, bi_max_vecs)
202 
203 /*
204  * bio flags
205  */
206 enum {
207         BIO_NO_PAGE_REF,        /* don't put release vec pages */
208         BIO_CLONED,             /* doesn't own data */
209         BIO_BOUNCED,            /* bio is a bounce bio */
210         BIO_USER_MAPPED,        /* contains user pages */
211         BIO_NULL_MAPPED,        /* contains invalid user pages */
212         BIO_QUIET,              /* Make BIO Quiet */
213         BIO_CHAIN,              /* chained bio, ->bi_remaining in effect */
214         BIO_REFFED,             /* bio has elevated ->bi_cnt */
215         BIO_THROTTLED,          /* This bio has already been subjected to
216                                  * throttling rules. Don't do it again. */
217         BIO_TRACE_COMPLETION,   /* bio_endio() should trace the final completion
218                                  * of this bio. */
219         BIO_QUEUE_ENTERED,      /* can use blk_queue_enter_live() */
220         BIO_TRACKED,            /* set if bio goes through the rq_qos path */
221         BIO_FLAG_LAST
222 };
223 
224 /* See BVEC_POOL_OFFSET below before adding new flags */
225 
226 /*
227  * We support 6 different bvec pools, the last one is magic in that it
228  * is backed by a mempool.
229  */
230 #define BVEC_POOL_NR            6
231 #define BVEC_POOL_MAX           (BVEC_POOL_NR - 1)
232 
233 /*
234  * Top 3 bits of bio flags indicate the pool the bvecs came from.  We add
235  * 1 to the actual index so that 0 indicates that there are no bvecs to be
236  * freed.
237  */
238 #define BVEC_POOL_BITS          (3)
239 #define BVEC_POOL_OFFSET        (16 - BVEC_POOL_BITS)
240 #define BVEC_POOL_IDX(bio)      ((bio)->bi_flags >> BVEC_POOL_OFFSET)
241 #if (1<< BVEC_POOL_BITS) < (BVEC_POOL_NR+1)
242 # error "BVEC_POOL_BITS is too small"
243 #endif
244 
245 /*
246  * Flags starting here get preserved by bio_reset() - this includes
247  * only BVEC_POOL_IDX()
248  */
249 #define BIO_RESET_BITS  BVEC_POOL_OFFSET
250 
251 typedef __u32 __bitwise blk_mq_req_flags_t;
252 
253 /*
254  * Operations and flags common to the bio and request structures.
255  * We use 8 bits for encoding the operation, and the remaining 24 for flags.
256  *
257  * The least significant bit of the operation number indicates the data
258  * transfer direction:
259  *
260  *   - if the least significant bit is set transfers are TO the device
261  *   - if the least significant bit is not set transfers are FROM the device
262  *
263  * If a operation does not transfer data the least significant bit has no
264  * meaning.
265  */
266 #define REQ_OP_BITS     8
267 #define REQ_OP_MASK     ((1 << REQ_OP_BITS) - 1)
268 #define REQ_FLAG_BITS   24
269 
270 enum req_opf {
271         /* read sectors from the device */
272         REQ_OP_READ             = 0,
273         /* write sectors to the device */
274         REQ_OP_WRITE            = 1,
275         /* flush the volatile write cache */
276         REQ_OP_FLUSH            = 2,
277         /* discard sectors */
278         REQ_OP_DISCARD          = 3,
279         /* securely erase sectors */
280         REQ_OP_SECURE_ERASE     = 5,
281         /* reset a zone write pointer */
282         REQ_OP_ZONE_RESET       = 6,
283         /* write the same sector many times */
284         REQ_OP_WRITE_SAME       = 7,
285         /* write the zero filled sector many times */
286         REQ_OP_WRITE_ZEROES     = 9,
287 
288         /* SCSI passthrough using struct scsi_request */
289         REQ_OP_SCSI_IN          = 32,
290         REQ_OP_SCSI_OUT         = 33,
291         /* Driver private requests */
292         REQ_OP_DRV_IN           = 34,
293         REQ_OP_DRV_OUT          = 35,
294 
295         REQ_OP_LAST,
296 };
297 
298 enum req_flag_bits {
299         __REQ_FAILFAST_DEV =    /* no driver retries of device errors */
300                 REQ_OP_BITS,
301         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
302         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
303         __REQ_SYNC,             /* request is sync (sync write or read) */
304         __REQ_META,             /* metadata io request */
305         __REQ_PRIO,             /* boost priority in cfq */
306         __REQ_NOMERGE,          /* don't touch this for merging */
307         __REQ_IDLE,             /* anticipate more IO after this one */
308         __REQ_INTEGRITY,        /* I/O includes block integrity payload */
309         __REQ_FUA,              /* forced unit access */
310         __REQ_PREFLUSH,         /* request for cache flush */
311         __REQ_RAHEAD,           /* read ahead, can fail anytime */
312         __REQ_BACKGROUND,       /* background IO */
313         __REQ_NOWAIT,           /* Don't wait if request will block */
314         /*
315          * When a shared kthread needs to issue a bio for a cgroup, doing
316          * so synchronously can lead to priority inversions as the kthread
317          * can be trapped waiting for that cgroup.  CGROUP_PUNT flag makes
318          * submit_bio() punt the actual issuing to a dedicated per-blkcg
319          * work item to avoid such priority inversions.
320          */
321         __REQ_CGROUP_PUNT,
322 
323         /* command specific flags for REQ_OP_WRITE_ZEROES: */
324         __REQ_NOUNMAP,          /* do not free blocks when zeroing */
325 
326         __REQ_HIPRI,
327 
328         /* for driver use */
329         __REQ_DRV,
330         __REQ_SWAP,             /* swapping request. */
331         __REQ_NR_BITS,          /* stops here */
332 };
333 
334 #define REQ_FAILFAST_DEV        (1ULL << __REQ_FAILFAST_DEV)
335 #define REQ_FAILFAST_TRANSPORT  (1ULL << __REQ_FAILFAST_TRANSPORT)
336 #define REQ_FAILFAST_DRIVER     (1ULL << __REQ_FAILFAST_DRIVER)
337 #define REQ_SYNC                (1ULL << __REQ_SYNC)
338 #define REQ_META                (1ULL << __REQ_META)
339 #define REQ_PRIO                (1ULL << __REQ_PRIO)
340 #define REQ_NOMERGE             (1ULL << __REQ_NOMERGE)
341 #define REQ_IDLE                (1ULL << __REQ_IDLE)
342 #define REQ_INTEGRITY           (1ULL << __REQ_INTEGRITY)
343 #define REQ_FUA                 (1ULL << __REQ_FUA)
344 #define REQ_PREFLUSH            (1ULL << __REQ_PREFLUSH)
345 #define REQ_RAHEAD              (1ULL << __REQ_RAHEAD)
346 #define REQ_BACKGROUND          (1ULL << __REQ_BACKGROUND)
347 #define REQ_NOWAIT              (1ULL << __REQ_NOWAIT)
348 #define REQ_CGROUP_PUNT         (1ULL << __REQ_CGROUP_PUNT)
349 
350 #define REQ_NOUNMAP             (1ULL << __REQ_NOUNMAP)
351 #define REQ_HIPRI               (1ULL << __REQ_HIPRI)
352 
353 #define REQ_DRV                 (1ULL << __REQ_DRV)
354 #define REQ_SWAP                (1ULL << __REQ_SWAP)
355 
356 #define REQ_FAILFAST_MASK \
357         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
358 
359 #define REQ_NOMERGE_FLAGS \
360         (REQ_NOMERGE | REQ_PREFLUSH | REQ_FUA)
361 
362 enum stat_group {
363         STAT_READ,
364         STAT_WRITE,
365         STAT_DISCARD,
366 
367         NR_STAT_GROUPS
368 };
369 
370 #define bio_op(bio) \
371         ((bio)->bi_opf & REQ_OP_MASK)
372 #define req_op(req) \
373         ((req)->cmd_flags & REQ_OP_MASK)
374 
375 /* obsolete, don't use in new code */
376 static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
377                 unsigned op_flags)
378 {
379         bio->bi_opf = op | op_flags;
380 }
381 
382 static inline bool op_is_write(unsigned int op)
383 {
384         return (op & 1);
385 }
386 
387 /*
388  * Check if the bio or request is one that needs special treatment in the
389  * flush state machine.
390  */
391 static inline bool op_is_flush(unsigned int op)
392 {
393         return op & (REQ_FUA | REQ_PREFLUSH);
394 }
395 
396 /*
397  * Reads are always treated as synchronous, as are requests with the FUA or
398  * PREFLUSH flag.  Other operations may be marked as synchronous using the
399  * REQ_SYNC flag.
400  */
401 static inline bool op_is_sync(unsigned int op)
402 {
403         return (op & REQ_OP_MASK) == REQ_OP_READ ||
404                 (op & (REQ_SYNC | REQ_FUA | REQ_PREFLUSH));
405 }
406 
407 static inline bool op_is_discard(unsigned int op)
408 {
409         return (op & REQ_OP_MASK) == REQ_OP_DISCARD;
410 }
411 
412 static inline int op_stat_group(unsigned int op)
413 {
414         if (op_is_discard(op))
415                 return STAT_DISCARD;
416         return op_is_write(op);
417 }
418 
419 typedef unsigned int blk_qc_t;
420 #define BLK_QC_T_NONE           -1U
421 #define BLK_QC_T_SHIFT          16
422 #define BLK_QC_T_INTERNAL       (1U << 31)
423 
424 static inline bool blk_qc_t_valid(blk_qc_t cookie)
425 {
426         return cookie != BLK_QC_T_NONE;
427 }
428 
429 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
430 {
431         return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
432 }
433 
434 static inline unsigned int blk_qc_t_to_tag(blk_qc_t cookie)
435 {
436         return cookie & ((1u << BLK_QC_T_SHIFT) - 1);
437 }
438 
439 static inline bool blk_qc_t_is_internal(blk_qc_t cookie)
440 {
441         return (cookie & BLK_QC_T_INTERNAL) != 0;
442 }
443 
444 struct blk_rq_stat {
445         u64 mean;
446         u64 min;
447         u64 max;
448         u32 nr_samples;
449         u64 batch;
450 };
451 
452 #endif /* __LINUX_BLK_TYPES_H */
453 

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