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

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  1 /*
  2  * 2.5 block I/O model
  3  *
  4  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful,
 11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  *
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public Licens
 17  * along with this program; if not, write to the Free Software
 18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 19  */
 20 #ifndef __LINUX_BIO_H
 21 #define __LINUX_BIO_H
 22 
 23 #include <linux/highmem.h>
 24 #include <linux/mempool.h>
 25 #include <linux/ioprio.h>
 26 #include <linux/bug.h>
 27 
 28 #ifdef CONFIG_BLOCK
 29 
 30 #include <asm/io.h>
 31 
 32 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
 33 #include <linux/blk_types.h>
 34 
 35 #define BIO_DEBUG
 36 
 37 #ifdef BIO_DEBUG
 38 #define BIO_BUG_ON      BUG_ON
 39 #else
 40 #define BIO_BUG_ON
 41 #endif
 42 
 43 #define BIO_MAX_PAGES           256
 44 #define BIO_MAX_SIZE            (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
 45 #define BIO_MAX_SECTORS         (BIO_MAX_SIZE >> 9)
 46 
 47 /*
 48  * upper 16 bits of bi_rw define the io priority of this bio
 49  */
 50 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
 51 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
 52 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
 53 
 54 #define bio_set_prio(bio, prio)         do {                    \
 55         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
 56         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
 57         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
 58 } while (0)
 59 
 60 /*
 61  * various member access, note that bio_data should of course not be used
 62  * on highmem page vectors
 63  */
 64 #define __bvec_iter_bvec(bvec, iter)    (&(bvec)[(iter).bi_idx])
 65 
 66 #define bvec_iter_page(bvec, iter)                              \
 67         (__bvec_iter_bvec((bvec), (iter))->bv_page)
 68 
 69 #define bvec_iter_len(bvec, iter)                               \
 70         min((iter).bi_size,                                     \
 71             __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
 72 
 73 #define bvec_iter_offset(bvec, iter)                            \
 74         (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
 75 
 76 #define bvec_iter_bvec(bvec, iter)                              \
 77 ((struct bio_vec) {                                             \
 78         .bv_page        = bvec_iter_page((bvec), (iter)),       \
 79         .bv_len         = bvec_iter_len((bvec), (iter)),        \
 80         .bv_offset      = bvec_iter_offset((bvec), (iter)),     \
 81 })
 82 
 83 #define bio_iter_iovec(bio, iter)                               \
 84         bvec_iter_bvec((bio)->bi_io_vec, (iter))
 85 
 86 #define bio_iter_page(bio, iter)                                \
 87         bvec_iter_page((bio)->bi_io_vec, (iter))
 88 #define bio_iter_len(bio, iter)                                 \
 89         bvec_iter_len((bio)->bi_io_vec, (iter))
 90 #define bio_iter_offset(bio, iter)                              \
 91         bvec_iter_offset((bio)->bi_io_vec, (iter))
 92 
 93 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
 94 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
 95 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
 96 
 97 #define bio_multiple_segments(bio)                              \
 98         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
 99 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
100 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
101 
102 /*
103  * Check whether this bio carries any data or not. A NULL bio is allowed.
104  */
105 static inline bool bio_has_data(struct bio *bio)
106 {
107         if (bio &&
108             bio->bi_iter.bi_size &&
109             !(bio->bi_rw & REQ_DISCARD))
110                 return true;
111 
112         return false;
113 }
114 
115 static inline bool bio_is_rw(struct bio *bio)
116 {
117         if (!bio_has_data(bio))
118                 return false;
119 
120         if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
121                 return false;
122 
123         return true;
124 }
125 
126 static inline bool bio_mergeable(struct bio *bio)
127 {
128         if (bio->bi_rw & REQ_NOMERGE_FLAGS)
129                 return false;
130 
131         return true;
132 }
133 
134 static inline unsigned int bio_cur_bytes(struct bio *bio)
135 {
136         if (bio_has_data(bio))
137                 return bio_iovec(bio).bv_len;
138         else /* dataless requests such as discard */
139                 return bio->bi_iter.bi_size;
140 }
141 
142 static inline void *bio_data(struct bio *bio)
143 {
144         if (bio_has_data(bio))
145                 return page_address(bio_page(bio)) + bio_offset(bio);
146 
147         return NULL;
148 }
149 
150 /*
151  * will die
152  */
153 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
154 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
155 
156 /*
157  * queues that have highmem support enabled may still need to revert to
158  * PIO transfers occasionally and thus map high pages temporarily. For
159  * permanent PIO fall back, user is probably better off disabling highmem
160  * I/O completely on that queue (see ide-dma for example)
161  */
162 #define __bio_kmap_atomic(bio, iter)                            \
163         (kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +   \
164                 bio_iter_iovec((bio), (iter)).bv_offset)
165 
166 #define __bio_kunmap_atomic(addr)       kunmap_atomic(addr)
167 
168 /*
169  * merge helpers etc
170  */
171 
172 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
173 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
174         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
175 
176 /*
177  * allow arch override, for eg virtualized architectures (put in asm/io.h)
178  */
179 #ifndef BIOVEC_PHYS_MERGEABLE
180 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
181         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
182 #endif
183 
184 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
185         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
186 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
187         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
188 
189 /*
190  * Check if adding a bio_vec after bprv with offset would create a gap in
191  * the SG list. Most drivers don't care about this, but some do.
192  */
193 static inline bool bvec_gap_to_prev(struct bio_vec *bprv, unsigned int offset)
194 {
195         return offset || ((bprv->bv_offset + bprv->bv_len) & (PAGE_SIZE - 1));
196 }
197 
198 #define bio_io_error(bio) bio_endio((bio), -EIO)
199 
200 /*
201  * drivers should _never_ use the all version - the bio may have been split
202  * before it got to the driver and the driver won't own all of it
203  */
204 #define bio_for_each_segment_all(bvl, bio, i)                           \
205         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
206 
207 static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
208                                      unsigned bytes)
209 {
210         WARN_ONCE(bytes > iter->bi_size,
211                   "Attempted to advance past end of bvec iter\n");
212 
213         while (bytes) {
214                 unsigned len = min(bytes, bvec_iter_len(bv, *iter));
215 
216                 bytes -= len;
217                 iter->bi_size -= len;
218                 iter->bi_bvec_done += len;
219 
220                 if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
221                         iter->bi_bvec_done = 0;
222                         iter->bi_idx++;
223                 }
224         }
225 }
226 
227 #define for_each_bvec(bvl, bio_vec, iter, start)                        \
228         for (iter = (start);                                            \
229              (iter).bi_size &&                                          \
230                 ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
231              bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
232 
233 
234 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
235                                     unsigned bytes)
236 {
237         iter->bi_sector += bytes >> 9;
238 
239         if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
240                 iter->bi_size -= bytes;
241         else
242                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
243 }
244 
245 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
246         for (iter = (start);                                            \
247              (iter).bi_size &&                                          \
248                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
249              bio_advance_iter((bio), &(iter), (bvl).bv_len))
250 
251 #define bio_for_each_segment(bvl, bio, iter)                            \
252         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
253 
254 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
255 
256 static inline unsigned bio_segments(struct bio *bio)
257 {
258         unsigned segs = 0;
259         struct bio_vec bv;
260         struct bvec_iter iter;
261 
262         /*
263          * We special case discard/write same, because they interpret bi_size
264          * differently:
265          */
266 
267         if (bio->bi_rw & REQ_DISCARD)
268                 return 1;
269 
270         if (bio->bi_rw & REQ_WRITE_SAME)
271                 return 1;
272 
273         bio_for_each_segment(bv, bio, iter)
274                 segs++;
275 
276         return segs;
277 }
278 
279 /*
280  * get a reference to a bio, so it won't disappear. the intended use is
281  * something like:
282  *
283  * bio_get(bio);
284  * submit_bio(rw, bio);
285  * if (bio->bi_flags ...)
286  *      do_something
287  * bio_put(bio);
288  *
289  * without the bio_get(), it could potentially complete I/O before submit_bio
290  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
291  * runs
292  */
293 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
294 
295 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
296 {
297         *bv = bio_iovec(bio);
298 }
299 
300 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
301 {
302         struct bvec_iter iter = bio->bi_iter;
303         int idx;
304 
305         if (!bio_flagged(bio, BIO_CLONED)) {
306                 *bv = bio->bi_io_vec[bio->bi_vcnt - 1];
307                 return;
308         }
309 
310         if (unlikely(!bio_multiple_segments(bio))) {
311                 *bv = bio_iovec(bio);
312                 return;
313         }
314 
315         bio_advance_iter(bio, &iter, iter.bi_size);
316 
317         if (!iter.bi_bvec_done)
318                 idx = iter.bi_idx - 1;
319         else    /* in the middle of bvec */
320                 idx = iter.bi_idx;
321 
322         *bv = bio->bi_io_vec[idx];
323 
324         /*
325          * iter.bi_bvec_done records actual length of the last bvec
326          * if this bio ends in the middle of one io vector
327          */
328         if (iter.bi_bvec_done)
329                 bv->bv_len = iter.bi_bvec_done;
330 }
331 
332 enum bip_flags {
333         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
334         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
335         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
336         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
337         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
338 };
339 
340 #if defined(CONFIG_BLK_DEV_INTEGRITY)
341 
342 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
343 {
344         if (bio->bi_rw & REQ_INTEGRITY)
345                 return bio->bi_integrity;
346 
347         return NULL;
348 }
349 
350 /*
351  * bio integrity payload
352  */
353 struct bio_integrity_payload {
354         struct bio              *bip_bio;       /* parent bio */
355 
356         struct bvec_iter        bip_iter;
357 
358         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
359 
360         unsigned short          bip_slab;       /* slab the bip came from */
361         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
362         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
363         unsigned short          bip_flags;      /* control flags */
364 
365         struct work_struct      bip_work;       /* I/O completion */
366 
367         struct bio_vec          *bip_vec;
368         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
369 };
370 
371 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
372 {
373         struct bio_integrity_payload *bip = bio_integrity(bio);
374 
375         if (bip)
376                 return bip->bip_flags & flag;
377 
378         return false;
379 }
380 
381 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
382 {
383         return bip->bip_iter.bi_sector;
384 }
385 
386 static inline void bip_set_seed(struct bio_integrity_payload *bip,
387                                 sector_t seed)
388 {
389         bip->bip_iter.bi_sector = seed;
390 }
391 
392 #endif /* CONFIG_BLK_DEV_INTEGRITY */
393 
394 extern void bio_trim(struct bio *bio, int offset, int size);
395 extern struct bio *bio_split(struct bio *bio, int sectors,
396                              gfp_t gfp, struct bio_set *bs);
397 
398 /**
399  * bio_next_split - get next @sectors from a bio, splitting if necessary
400  * @bio:        bio to split
401  * @sectors:    number of sectors to split from the front of @bio
402  * @gfp:        gfp mask
403  * @bs:         bio set to allocate from
404  *
405  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
406  * than @sectors, returns the original bio unchanged.
407  */
408 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
409                                          gfp_t gfp, struct bio_set *bs)
410 {
411         if (sectors >= bio_sectors(bio))
412                 return bio;
413 
414         return bio_split(bio, sectors, gfp, bs);
415 }
416 
417 extern struct bio_set *bioset_create(unsigned int, unsigned int);
418 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
419 extern void bioset_free(struct bio_set *);
420 extern mempool_t *biovec_create_pool(int pool_entries);
421 
422 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
423 extern void bio_put(struct bio *);
424 
425 extern void __bio_clone_fast(struct bio *, struct bio *);
426 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
427 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
428 
429 extern struct bio_set *fs_bio_set;
430 
431 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
432 {
433         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
434 }
435 
436 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
437 {
438         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
439 }
440 
441 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
442 {
443         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
444 }
445 
446 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
447 {
448         return bio_clone_bioset(bio, gfp_mask, NULL);
449 
450 }
451 
452 extern void bio_endio(struct bio *, int);
453 extern void bio_endio_nodec(struct bio *, int);
454 struct request_queue;
455 extern int bio_phys_segments(struct request_queue *, struct bio *);
456 
457 extern int submit_bio_wait(int rw, struct bio *bio);
458 extern void bio_advance(struct bio *, unsigned);
459 
460 extern void bio_init(struct bio *);
461 extern void bio_reset(struct bio *);
462 void bio_chain(struct bio *, struct bio *);
463 
464 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
465 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
466                            unsigned int, unsigned int);
467 extern int bio_get_nr_vecs(struct block_device *);
468 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
469                                 unsigned long, unsigned int, int, gfp_t);
470 struct sg_iovec;
471 struct rq_map_data;
472 extern struct bio *bio_map_user_iov(struct request_queue *,
473                                     struct block_device *,
474                                     const struct sg_iovec *, int, int, gfp_t);
475 extern void bio_unmap_user(struct bio *);
476 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
477                                 gfp_t);
478 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
479                                  gfp_t, int);
480 extern void bio_set_pages_dirty(struct bio *bio);
481 extern void bio_check_pages_dirty(struct bio *bio);
482 
483 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
484 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
485 #endif
486 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
487 extern void bio_flush_dcache_pages(struct bio *bi);
488 #else
489 static inline void bio_flush_dcache_pages(struct bio *bi)
490 {
491 }
492 #endif
493 
494 extern void bio_copy_data(struct bio *dst, struct bio *src);
495 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
496 
497 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
498                                  unsigned long, unsigned int, int, gfp_t);
499 extern struct bio *bio_copy_user_iov(struct request_queue *,
500                                      struct rq_map_data *,
501                                      const struct sg_iovec *,
502                                      int, int, gfp_t);
503 extern int bio_uncopy_user(struct bio *);
504 void zero_fill_bio(struct bio *bio);
505 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
506 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
507 extern unsigned int bvec_nr_vecs(unsigned short idx);
508 
509 #ifdef CONFIG_BLK_CGROUP
510 int bio_associate_current(struct bio *bio);
511 void bio_disassociate_task(struct bio *bio);
512 #else   /* CONFIG_BLK_CGROUP */
513 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
514 static inline void bio_disassociate_task(struct bio *bio) { }
515 #endif  /* CONFIG_BLK_CGROUP */
516 
517 #ifdef CONFIG_HIGHMEM
518 /*
519  * remember never ever reenable interrupts between a bvec_kmap_irq and
520  * bvec_kunmap_irq!
521  */
522 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
523 {
524         unsigned long addr;
525 
526         /*
527          * might not be a highmem page, but the preempt/irq count
528          * balancing is a lot nicer this way
529          */
530         local_irq_save(*flags);
531         addr = (unsigned long) kmap_atomic(bvec->bv_page);
532 
533         BUG_ON(addr & ~PAGE_MASK);
534 
535         return (char *) addr + bvec->bv_offset;
536 }
537 
538 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
539 {
540         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
541 
542         kunmap_atomic((void *) ptr);
543         local_irq_restore(*flags);
544 }
545 
546 #else
547 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
548 {
549         return page_address(bvec->bv_page) + bvec->bv_offset;
550 }
551 
552 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
553 {
554         *flags = 0;
555 }
556 #endif
557 
558 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
559                                    unsigned long *flags)
560 {
561         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
562 }
563 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
564 
565 #define bio_kmap_irq(bio, flags) \
566         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
567 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
568 
569 /*
570  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
571  *
572  * A bio_list anchors a singly-linked list of bios chained through the bi_next
573  * member of the bio.  The bio_list also caches the last list member to allow
574  * fast access to the tail.
575  */
576 struct bio_list {
577         struct bio *head;
578         struct bio *tail;
579 };
580 
581 static inline int bio_list_empty(const struct bio_list *bl)
582 {
583         return bl->head == NULL;
584 }
585 
586 static inline void bio_list_init(struct bio_list *bl)
587 {
588         bl->head = bl->tail = NULL;
589 }
590 
591 #define BIO_EMPTY_LIST  { NULL, NULL }
592 
593 #define bio_list_for_each(bio, bl) \
594         for (bio = (bl)->head; bio; bio = bio->bi_next)
595 
596 static inline unsigned bio_list_size(const struct bio_list *bl)
597 {
598         unsigned sz = 0;
599         struct bio *bio;
600 
601         bio_list_for_each(bio, bl)
602                 sz++;
603 
604         return sz;
605 }
606 
607 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
608 {
609         bio->bi_next = NULL;
610 
611         if (bl->tail)
612                 bl->tail->bi_next = bio;
613         else
614                 bl->head = bio;
615 
616         bl->tail = bio;
617 }
618 
619 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
620 {
621         bio->bi_next = bl->head;
622 
623         bl->head = bio;
624 
625         if (!bl->tail)
626                 bl->tail = bio;
627 }
628 
629 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
630 {
631         if (!bl2->head)
632                 return;
633 
634         if (bl->tail)
635                 bl->tail->bi_next = bl2->head;
636         else
637                 bl->head = bl2->head;
638 
639         bl->tail = bl2->tail;
640 }
641 
642 static inline void bio_list_merge_head(struct bio_list *bl,
643                                        struct bio_list *bl2)
644 {
645         if (!bl2->head)
646                 return;
647 
648         if (bl->head)
649                 bl2->tail->bi_next = bl->head;
650         else
651                 bl->tail = bl2->tail;
652 
653         bl->head = bl2->head;
654 }
655 
656 static inline struct bio *bio_list_peek(struct bio_list *bl)
657 {
658         return bl->head;
659 }
660 
661 static inline struct bio *bio_list_pop(struct bio_list *bl)
662 {
663         struct bio *bio = bl->head;
664 
665         if (bio) {
666                 bl->head = bl->head->bi_next;
667                 if (!bl->head)
668                         bl->tail = NULL;
669 
670                 bio->bi_next = NULL;
671         }
672 
673         return bio;
674 }
675 
676 static inline struct bio *bio_list_get(struct bio_list *bl)
677 {
678         struct bio *bio = bl->head;
679 
680         bl->head = bl->tail = NULL;
681 
682         return bio;
683 }
684 
685 /*
686  * bio_set is used to allow other portions of the IO system to
687  * allocate their own private memory pools for bio and iovec structures.
688  * These memory pools in turn all allocate from the bio_slab
689  * and the bvec_slabs[].
690  */
691 #define BIO_POOL_SIZE 2
692 #define BIOVEC_NR_POOLS 6
693 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
694 
695 struct bio_set {
696         struct kmem_cache *bio_slab;
697         unsigned int front_pad;
698 
699         mempool_t *bio_pool;
700         mempool_t *bvec_pool;
701 #if defined(CONFIG_BLK_DEV_INTEGRITY)
702         mempool_t *bio_integrity_pool;
703         mempool_t *bvec_integrity_pool;
704 #endif
705 
706         /*
707          * Deadlock avoidance for stacking block drivers: see comments in
708          * bio_alloc_bioset() for details
709          */
710         spinlock_t              rescue_lock;
711         struct bio_list         rescue_list;
712         struct work_struct      rescue_work;
713         struct workqueue_struct *rescue_workqueue;
714 };
715 
716 struct biovec_slab {
717         int nr_vecs;
718         char *name;
719         struct kmem_cache *slab;
720 };
721 
722 /*
723  * a small number of entries is fine, not going to be performance critical.
724  * basically we just need to survive
725  */
726 #define BIO_SPLIT_ENTRIES 2
727 
728 #if defined(CONFIG_BLK_DEV_INTEGRITY)
729 
730 #define bip_for_each_vec(bvl, bip, iter)                                \
731         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
732 
733 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
734         for_each_bio(_bio)                                              \
735                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
736 
737 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
738 extern void bio_integrity_free(struct bio *);
739 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
740 extern bool bio_integrity_enabled(struct bio *bio);
741 extern int bio_integrity_prep(struct bio *);
742 extern void bio_integrity_endio(struct bio *, int);
743 extern void bio_integrity_advance(struct bio *, unsigned int);
744 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
745 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
746 extern int bioset_integrity_create(struct bio_set *, int);
747 extern void bioset_integrity_free(struct bio_set *);
748 extern void bio_integrity_init(void);
749 
750 #else /* CONFIG_BLK_DEV_INTEGRITY */
751 
752 static inline void *bio_integrity(struct bio *bio)
753 {
754         return NULL;
755 }
756 
757 static inline bool bio_integrity_enabled(struct bio *bio)
758 {
759         return false;
760 }
761 
762 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
763 {
764         return 0;
765 }
766 
767 static inline void bioset_integrity_free (struct bio_set *bs)
768 {
769         return;
770 }
771 
772 static inline int bio_integrity_prep(struct bio *bio)
773 {
774         return 0;
775 }
776 
777 static inline void bio_integrity_free(struct bio *bio)
778 {
779         return;
780 }
781 
782 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
783                                       gfp_t gfp_mask)
784 {
785         return 0;
786 }
787 
788 static inline void bio_integrity_advance(struct bio *bio,
789                                          unsigned int bytes_done)
790 {
791         return;
792 }
793 
794 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
795                                       unsigned int sectors)
796 {
797         return;
798 }
799 
800 static inline void bio_integrity_init(void)
801 {
802         return;
803 }
804 
805 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
806 {
807         return false;
808 }
809 
810 #endif /* CONFIG_BLK_DEV_INTEGRITY */
811 
812 #endif /* CONFIG_BLOCK */
813 #endif /* __LINUX_BIO_H */
814 

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