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

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  1 /*
  2  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License version 2 as
  6  * published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  *
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  *
 14  * You should have received a copy of the GNU General Public Licens
 15  * along with this program; if not, write to the Free Software
 16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 17  */
 18 #ifndef __LINUX_BIO_H
 19 #define __LINUX_BIO_H
 20 
 21 #include <linux/highmem.h>
 22 #include <linux/mempool.h>
 23 #include <linux/ioprio.h>
 24 #include <linux/bug.h>
 25 
 26 #ifdef CONFIG_BLOCK
 27 
 28 #include <asm/io.h>
 29 
 30 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
 31 #include <linux/blk_types.h>
 32 
 33 #define BIO_DEBUG
 34 
 35 #ifdef BIO_DEBUG
 36 #define BIO_BUG_ON      BUG_ON
 37 #else
 38 #define BIO_BUG_ON
 39 #endif
 40 
 41 #ifdef CONFIG_THP_SWAP
 42 #if HPAGE_PMD_NR > 256
 43 #define BIO_MAX_PAGES           HPAGE_PMD_NR
 44 #else
 45 #define BIO_MAX_PAGES           256
 46 #endif
 47 #else
 48 #define BIO_MAX_PAGES           256
 49 #endif
 50 
 51 #define bio_prio(bio)                   (bio)->bi_ioprio
 52 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
 53 
 54 #define bio_iter_iovec(bio, iter)                               \
 55         bvec_iter_bvec((bio)->bi_io_vec, (iter))
 56 
 57 #define bio_iter_page(bio, iter)                                \
 58         bvec_iter_page((bio)->bi_io_vec, (iter))
 59 #define bio_iter_len(bio, iter)                                 \
 60         bvec_iter_len((bio)->bi_io_vec, (iter))
 61 #define bio_iter_offset(bio, iter)                              \
 62         bvec_iter_offset((bio)->bi_io_vec, (iter))
 63 
 64 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
 65 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
 66 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
 67 
 68 #define bio_multiple_segments(bio)                              \
 69         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
 70 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
 71 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
 72 
 73 /*
 74  * Return the data direction, READ or WRITE.
 75  */
 76 #define bio_data_dir(bio) \
 77         (op_is_write(bio_op(bio)) ? WRITE : READ)
 78 
 79 /*
 80  * Check whether this bio carries any data or not. A NULL bio is allowed.
 81  */
 82 static inline bool bio_has_data(struct bio *bio)
 83 {
 84         if (bio &&
 85             bio->bi_iter.bi_size &&
 86             bio_op(bio) != REQ_OP_DISCARD &&
 87             bio_op(bio) != REQ_OP_SECURE_ERASE &&
 88             bio_op(bio) != REQ_OP_WRITE_ZEROES)
 89                 return true;
 90 
 91         return false;
 92 }
 93 
 94 static inline bool bio_no_advance_iter(struct bio *bio)
 95 {
 96         return bio_op(bio) == REQ_OP_DISCARD ||
 97                bio_op(bio) == REQ_OP_SECURE_ERASE ||
 98                bio_op(bio) == REQ_OP_WRITE_SAME ||
 99                bio_op(bio) == REQ_OP_WRITE_ZEROES;
100 }
101 
102 static inline bool bio_mergeable(struct bio *bio)
103 {
104         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
105                 return false;
106 
107         return true;
108 }
109 
110 static inline unsigned int bio_cur_bytes(struct bio *bio)
111 {
112         if (bio_has_data(bio))
113                 return bio_iovec(bio).bv_len;
114         else /* dataless requests such as discard */
115                 return bio->bi_iter.bi_size;
116 }
117 
118 static inline void *bio_data(struct bio *bio)
119 {
120         if (bio_has_data(bio))
121                 return page_address(bio_page(bio)) + bio_offset(bio);
122 
123         return NULL;
124 }
125 
126 /*
127  * will die
128  */
129 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
130 
131 /*
132  * merge helpers etc
133  */
134 
135 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
136 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
137         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
138 
139 /*
140  * allow arch override, for eg virtualized architectures (put in asm/io.h)
141  */
142 #ifndef BIOVEC_PHYS_MERGEABLE
143 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
144         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
145 #endif
146 
147 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
148         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
149 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
150         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
151 
152 /*
153  * drivers should _never_ use the all version - the bio may have been split
154  * before it got to the driver and the driver won't own all of it
155  */
156 #define bio_for_each_segment_all(bvl, bio, i)                           \
157         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
158 
159 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
160                                     unsigned bytes)
161 {
162         iter->bi_sector += bytes >> 9;
163 
164         if (bio_no_advance_iter(bio)) {
165                 iter->bi_size -= bytes;
166                 iter->bi_done += bytes;
167         } else {
168                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
169                 /* TODO: It is reasonable to complete bio with error here. */
170         }
171 }
172 
173 static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
174                 unsigned int bytes)
175 {
176         iter->bi_sector -= bytes >> 9;
177 
178         if (bio_no_advance_iter(bio)) {
179                 iter->bi_size += bytes;
180                 iter->bi_done -= bytes;
181                 return true;
182         }
183 
184         return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
185 }
186 
187 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
188         for (iter = (start);                                            \
189              (iter).bi_size &&                                          \
190                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
191              bio_advance_iter((bio), &(iter), (bvl).bv_len))
192 
193 #define bio_for_each_segment(bvl, bio, iter)                            \
194         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
195 
196 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
197 
198 static inline unsigned bio_segments(struct bio *bio)
199 {
200         unsigned segs = 0;
201         struct bio_vec bv;
202         struct bvec_iter iter;
203 
204         /*
205          * We special case discard/write same/write zeroes, because they
206          * interpret bi_size differently:
207          */
208 
209         switch (bio_op(bio)) {
210         case REQ_OP_DISCARD:
211         case REQ_OP_SECURE_ERASE:
212         case REQ_OP_WRITE_ZEROES:
213                 return 0;
214         case REQ_OP_WRITE_SAME:
215                 return 1;
216         default:
217                 break;
218         }
219 
220         bio_for_each_segment(bv, bio, iter)
221                 segs++;
222 
223         return segs;
224 }
225 
226 /*
227  * get a reference to a bio, so it won't disappear. the intended use is
228  * something like:
229  *
230  * bio_get(bio);
231  * submit_bio(rw, bio);
232  * if (bio->bi_flags ...)
233  *      do_something
234  * bio_put(bio);
235  *
236  * without the bio_get(), it could potentially complete I/O before submit_bio
237  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
238  * runs
239  */
240 static inline void bio_get(struct bio *bio)
241 {
242         bio->bi_flags |= (1 << BIO_REFFED);
243         smp_mb__before_atomic();
244         atomic_inc(&bio->__bi_cnt);
245 }
246 
247 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
248 {
249         if (count != 1) {
250                 bio->bi_flags |= (1 << BIO_REFFED);
251                 smp_mb__before_atomic();
252         }
253         atomic_set(&bio->__bi_cnt, count);
254 }
255 
256 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
257 {
258         return (bio->bi_flags & (1U << bit)) != 0;
259 }
260 
261 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
262 {
263         bio->bi_flags |= (1U << bit);
264 }
265 
266 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
267 {
268         bio->bi_flags &= ~(1U << bit);
269 }
270 
271 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
272 {
273         *bv = bio_iovec(bio);
274 }
275 
276 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
277 {
278         struct bvec_iter iter = bio->bi_iter;
279         int idx;
280 
281         if (unlikely(!bio_multiple_segments(bio))) {
282                 *bv = bio_iovec(bio);
283                 return;
284         }
285 
286         bio_advance_iter(bio, &iter, iter.bi_size);
287 
288         if (!iter.bi_bvec_done)
289                 idx = iter.bi_idx - 1;
290         else    /* in the middle of bvec */
291                 idx = iter.bi_idx;
292 
293         *bv = bio->bi_io_vec[idx];
294 
295         /*
296          * iter.bi_bvec_done records actual length of the last bvec
297          * if this bio ends in the middle of one io vector
298          */
299         if (iter.bi_bvec_done)
300                 bv->bv_len = iter.bi_bvec_done;
301 }
302 
303 enum bip_flags {
304         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
305         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
306         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
307         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
308         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
309 };
310 
311 /*
312  * bio integrity payload
313  */
314 struct bio_integrity_payload {
315         struct bio              *bip_bio;       /* parent bio */
316 
317         struct bvec_iter        bip_iter;
318 
319         unsigned short          bip_slab;       /* slab the bip came from */
320         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
321         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
322         unsigned short          bip_flags;      /* control flags */
323 
324         struct work_struct      bip_work;       /* I/O completion */
325 
326         struct bio_vec          *bip_vec;
327         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
328 };
329 
330 #if defined(CONFIG_BLK_DEV_INTEGRITY)
331 
332 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
333 {
334         if (bio->bi_opf & REQ_INTEGRITY)
335                 return bio->bi_integrity;
336 
337         return NULL;
338 }
339 
340 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
341 {
342         struct bio_integrity_payload *bip = bio_integrity(bio);
343 
344         if (bip)
345                 return bip->bip_flags & flag;
346 
347         return false;
348 }
349 
350 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
351 {
352         return bip->bip_iter.bi_sector;
353 }
354 
355 static inline void bip_set_seed(struct bio_integrity_payload *bip,
356                                 sector_t seed)
357 {
358         bip->bip_iter.bi_sector = seed;
359 }
360 
361 #endif /* CONFIG_BLK_DEV_INTEGRITY */
362 
363 extern void bio_trim(struct bio *bio, int offset, int size);
364 extern struct bio *bio_split(struct bio *bio, int sectors,
365                              gfp_t gfp, struct bio_set *bs);
366 
367 /**
368  * bio_next_split - get next @sectors from a bio, splitting if necessary
369  * @bio:        bio to split
370  * @sectors:    number of sectors to split from the front of @bio
371  * @gfp:        gfp mask
372  * @bs:         bio set to allocate from
373  *
374  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
375  * than @sectors, returns the original bio unchanged.
376  */
377 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
378                                          gfp_t gfp, struct bio_set *bs)
379 {
380         if (sectors >= bio_sectors(bio))
381                 return bio;
382 
383         return bio_split(bio, sectors, gfp, bs);
384 }
385 
386 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
387 enum {
388         BIOSET_NEED_BVECS = BIT(0),
389         BIOSET_NEED_RESCUER = BIT(1),
390 };
391 extern void bioset_free(struct bio_set *);
392 extern mempool_t *biovec_create_pool(int pool_entries);
393 
394 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
395 extern void bio_put(struct bio *);
396 
397 extern void __bio_clone_fast(struct bio *, struct bio *);
398 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
399 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
400 
401 extern struct bio_set *fs_bio_set;
402 
403 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
404 {
405         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
406 }
407 
408 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
409 {
410         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
411 }
412 
413 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
414 {
415         return bio_clone_bioset(bio, gfp_mask, NULL);
416 
417 }
418 
419 extern blk_qc_t submit_bio(struct bio *);
420 
421 extern void bio_endio(struct bio *);
422 
423 static inline void bio_io_error(struct bio *bio)
424 {
425         bio->bi_status = BLK_STS_IOERR;
426         bio_endio(bio);
427 }
428 
429 static inline void bio_wouldblock_error(struct bio *bio)
430 {
431         bio->bi_status = BLK_STS_AGAIN;
432         bio_endio(bio);
433 }
434 
435 struct request_queue;
436 extern int bio_phys_segments(struct request_queue *, struct bio *);
437 
438 extern int submit_bio_wait(struct bio *bio);
439 extern void bio_advance(struct bio *, unsigned);
440 
441 extern void bio_init(struct bio *bio, struct bio_vec *table,
442                      unsigned short max_vecs);
443 extern void bio_uninit(struct bio *);
444 extern void bio_reset(struct bio *);
445 void bio_chain(struct bio *, struct bio *);
446 
447 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
448 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
449                            unsigned int, unsigned int);
450 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
451 struct rq_map_data;
452 extern struct bio *bio_map_user_iov(struct request_queue *,
453                                     struct iov_iter *, gfp_t);
454 extern void bio_unmap_user(struct bio *);
455 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
456                                 gfp_t);
457 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
458                                  gfp_t, int);
459 extern void bio_set_pages_dirty(struct bio *bio);
460 extern void bio_check_pages_dirty(struct bio *bio);
461 
462 void generic_start_io_acct(struct request_queue *q, int rw,
463                                 unsigned long sectors, struct hd_struct *part);
464 void generic_end_io_acct(struct request_queue *q, int rw,
465                                 struct hd_struct *part,
466                                 unsigned long start_time);
467 
468 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
469 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
470 #endif
471 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
472 extern void bio_flush_dcache_pages(struct bio *bi);
473 #else
474 static inline void bio_flush_dcache_pages(struct bio *bi)
475 {
476 }
477 #endif
478 
479 extern void bio_copy_data(struct bio *dst, struct bio *src);
480 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
481 extern void bio_free_pages(struct bio *bio);
482 
483 extern struct bio *bio_copy_user_iov(struct request_queue *,
484                                      struct rq_map_data *,
485                                      struct iov_iter *,
486                                      gfp_t);
487 extern int bio_uncopy_user(struct bio *);
488 void zero_fill_bio(struct bio *bio);
489 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
490 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
491 extern unsigned int bvec_nr_vecs(unsigned short idx);
492 
493 #define bio_set_dev(bio, bdev)                  \
494 do {                                            \
495         if ((bio)->bi_disk != (bdev)->bd_disk)  \
496                 bio_clear_flag(bio, BIO_THROTTLED);\
497         (bio)->bi_disk = (bdev)->bd_disk;       \
498         (bio)->bi_partno = (bdev)->bd_partno;   \
499 } while (0)
500 
501 #define bio_copy_dev(dst, src)                  \
502 do {                                            \
503         (dst)->bi_disk = (src)->bi_disk;        \
504         (dst)->bi_partno = (src)->bi_partno;    \
505 } while (0)
506 
507 #define bio_dev(bio) \
508         disk_devt((bio)->bi_disk)
509 
510 #define bio_devname(bio, buf) \
511         __bdevname(bio_dev(bio), (buf))
512 
513 #ifdef CONFIG_BLK_CGROUP
514 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
515 void bio_disassociate_task(struct bio *bio);
516 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
517 #else   /* CONFIG_BLK_CGROUP */
518 static inline int bio_associate_blkcg(struct bio *bio,
519                         struct cgroup_subsys_state *blkcg_css) { return 0; }
520 static inline void bio_disassociate_task(struct bio *bio) { }
521 static inline void bio_clone_blkcg_association(struct bio *dst,
522                         struct bio *src) { }
523 #endif  /* CONFIG_BLK_CGROUP */
524 
525 #ifdef CONFIG_HIGHMEM
526 /*
527  * remember never ever reenable interrupts between a bvec_kmap_irq and
528  * bvec_kunmap_irq!
529  */
530 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
531 {
532         unsigned long addr;
533 
534         /*
535          * might not be a highmem page, but the preempt/irq count
536          * balancing is a lot nicer this way
537          */
538         local_irq_save(*flags);
539         addr = (unsigned long) kmap_atomic(bvec->bv_page);
540 
541         BUG_ON(addr & ~PAGE_MASK);
542 
543         return (char *) addr + bvec->bv_offset;
544 }
545 
546 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
547 {
548         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
549 
550         kunmap_atomic((void *) ptr);
551         local_irq_restore(*flags);
552 }
553 
554 #else
555 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
556 {
557         return page_address(bvec->bv_page) + bvec->bv_offset;
558 }
559 
560 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
561 {
562         *flags = 0;
563 }
564 #endif
565 
566 /*
567  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
568  *
569  * A bio_list anchors a singly-linked list of bios chained through the bi_next
570  * member of the bio.  The bio_list also caches the last list member to allow
571  * fast access to the tail.
572  */
573 struct bio_list {
574         struct bio *head;
575         struct bio *tail;
576 };
577 
578 static inline int bio_list_empty(const struct bio_list *bl)
579 {
580         return bl->head == NULL;
581 }
582 
583 static inline void bio_list_init(struct bio_list *bl)
584 {
585         bl->head = bl->tail = NULL;
586 }
587 
588 #define BIO_EMPTY_LIST  { NULL, NULL }
589 
590 #define bio_list_for_each(bio, bl) \
591         for (bio = (bl)->head; bio; bio = bio->bi_next)
592 
593 static inline unsigned bio_list_size(const struct bio_list *bl)
594 {
595         unsigned sz = 0;
596         struct bio *bio;
597 
598         bio_list_for_each(bio, bl)
599                 sz++;
600 
601         return sz;
602 }
603 
604 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
605 {
606         bio->bi_next = NULL;
607 
608         if (bl->tail)
609                 bl->tail->bi_next = bio;
610         else
611                 bl->head = bio;
612 
613         bl->tail = bio;
614 }
615 
616 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
617 {
618         bio->bi_next = bl->head;
619 
620         bl->head = bio;
621 
622         if (!bl->tail)
623                 bl->tail = bio;
624 }
625 
626 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
627 {
628         if (!bl2->head)
629                 return;
630 
631         if (bl->tail)
632                 bl->tail->bi_next = bl2->head;
633         else
634                 bl->head = bl2->head;
635 
636         bl->tail = bl2->tail;
637 }
638 
639 static inline void bio_list_merge_head(struct bio_list *bl,
640                                        struct bio_list *bl2)
641 {
642         if (!bl2->head)
643                 return;
644 
645         if (bl->head)
646                 bl2->tail->bi_next = bl->head;
647         else
648                 bl->tail = bl2->tail;
649 
650         bl->head = bl2->head;
651 }
652 
653 static inline struct bio *bio_list_peek(struct bio_list *bl)
654 {
655         return bl->head;
656 }
657 
658 static inline struct bio *bio_list_pop(struct bio_list *bl)
659 {
660         struct bio *bio = bl->head;
661 
662         if (bio) {
663                 bl->head = bl->head->bi_next;
664                 if (!bl->head)
665                         bl->tail = NULL;
666 
667                 bio->bi_next = NULL;
668         }
669 
670         return bio;
671 }
672 
673 static inline struct bio *bio_list_get(struct bio_list *bl)
674 {
675         struct bio *bio = bl->head;
676 
677         bl->head = bl->tail = NULL;
678 
679         return bio;
680 }
681 
682 /*
683  * Increment chain count for the bio. Make sure the CHAIN flag update
684  * is visible before the raised count.
685  */
686 static inline void bio_inc_remaining(struct bio *bio)
687 {
688         bio_set_flag(bio, BIO_CHAIN);
689         smp_mb__before_atomic();
690         atomic_inc(&bio->__bi_remaining);
691 }
692 
693 /*
694  * bio_set is used to allow other portions of the IO system to
695  * allocate their own private memory pools for bio and iovec structures.
696  * These memory pools in turn all allocate from the bio_slab
697  * and the bvec_slabs[].
698  */
699 #define BIO_POOL_SIZE 2
700 
701 struct bio_set {
702         struct kmem_cache *bio_slab;
703         unsigned int front_pad;
704 
705         mempool_t *bio_pool;
706         mempool_t *bvec_pool;
707 #if defined(CONFIG_BLK_DEV_INTEGRITY)
708         mempool_t *bio_integrity_pool;
709         mempool_t *bvec_integrity_pool;
710 #endif
711 
712         /*
713          * Deadlock avoidance for stacking block drivers: see comments in
714          * bio_alloc_bioset() for details
715          */
716         spinlock_t              rescue_lock;
717         struct bio_list         rescue_list;
718         struct work_struct      rescue_work;
719         struct workqueue_struct *rescue_workqueue;
720 };
721 
722 struct biovec_slab {
723         int nr_vecs;
724         char *name;
725         struct kmem_cache *slab;
726 };
727 
728 /*
729  * a small number of entries is fine, not going to be performance critical.
730  * basically we just need to survive
731  */
732 #define BIO_SPLIT_ENTRIES 2
733 
734 #if defined(CONFIG_BLK_DEV_INTEGRITY)
735 
736 #define bip_for_each_vec(bvl, bip, iter)                                \
737         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
738 
739 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
740         for_each_bio(_bio)                                              \
741                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
742 
743 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
744 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
745 extern bool bio_integrity_prep(struct bio *);
746 extern void bio_integrity_advance(struct bio *, unsigned int);
747 extern void bio_integrity_trim(struct bio *);
748 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
749 extern int bioset_integrity_create(struct bio_set *, int);
750 extern void bioset_integrity_free(struct bio_set *);
751 extern void bio_integrity_init(void);
752 
753 #else /* CONFIG_BLK_DEV_INTEGRITY */
754 
755 static inline void *bio_integrity(struct bio *bio)
756 {
757         return NULL;
758 }
759 
760 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
761 {
762         return 0;
763 }
764 
765 static inline void bioset_integrity_free (struct bio_set *bs)
766 {
767         return;
768 }
769 
770 static inline bool bio_integrity_prep(struct bio *bio)
771 {
772         return true;
773 }
774 
775 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
776                                       gfp_t gfp_mask)
777 {
778         return 0;
779 }
780 
781 static inline void bio_integrity_advance(struct bio *bio,
782                                          unsigned int bytes_done)
783 {
784         return;
785 }
786 
787 static inline void bio_integrity_trim(struct bio *bio)
788 {
789         return;
790 }
791 
792 static inline void bio_integrity_init(void)
793 {
794         return;
795 }
796 
797 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
798 {
799         return false;
800 }
801 
802 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
803                                                                 unsigned int nr)
804 {
805         return ERR_PTR(-EINVAL);
806 }
807 
808 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
809                                         unsigned int len, unsigned int offset)
810 {
811         return 0;
812 }
813 
814 #endif /* CONFIG_BLK_DEV_INTEGRITY */
815 
816 #endif /* CONFIG_BLOCK */
817 #endif /* __LINUX_BIO_H */
818 

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