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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 static inline void bio_get(struct bio *bio)
294 {
295         bio->bi_flags |= (1 << BIO_REFFED);
296         smp_mb__before_atomic();
297         atomic_inc(&bio->__bi_cnt);
298 }
299 
300 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
301 {
302         if (count != 1) {
303                 bio->bi_flags |= (1 << BIO_REFFED);
304                 smp_mb__before_atomic();
305         }
306         atomic_set(&bio->__bi_cnt, count);
307 }
308 
309 enum bip_flags {
310         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
311         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
312         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
313         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
314         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
315 };
316 
317 #if defined(CONFIG_BLK_DEV_INTEGRITY)
318 
319 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
320 {
321         if (bio->bi_rw & REQ_INTEGRITY)
322                 return bio->bi_integrity;
323 
324         return NULL;
325 }
326 
327 /*
328  * bio integrity payload
329  */
330 struct bio_integrity_payload {
331         struct bio              *bip_bio;       /* parent bio */
332 
333         struct bvec_iter        bip_iter;
334 
335         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
336 
337         unsigned short          bip_slab;       /* slab the bip came from */
338         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
339         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
340         unsigned short          bip_flags;      /* control flags */
341 
342         struct work_struct      bip_work;       /* I/O completion */
343 
344         struct bio_vec          *bip_vec;
345         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
346 };
347 
348 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
349 {
350         struct bio_integrity_payload *bip = bio_integrity(bio);
351 
352         if (bip)
353                 return bip->bip_flags & flag;
354 
355         return false;
356 }
357 
358 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
359 {
360         return bip->bip_iter.bi_sector;
361 }
362 
363 static inline void bip_set_seed(struct bio_integrity_payload *bip,
364                                 sector_t seed)
365 {
366         bip->bip_iter.bi_sector = seed;
367 }
368 
369 #endif /* CONFIG_BLK_DEV_INTEGRITY */
370 
371 extern void bio_trim(struct bio *bio, int offset, int size);
372 extern struct bio *bio_split(struct bio *bio, int sectors,
373                              gfp_t gfp, struct bio_set *bs);
374 
375 /**
376  * bio_next_split - get next @sectors from a bio, splitting if necessary
377  * @bio:        bio to split
378  * @sectors:    number of sectors to split from the front of @bio
379  * @gfp:        gfp mask
380  * @bs:         bio set to allocate from
381  *
382  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
383  * than @sectors, returns the original bio unchanged.
384  */
385 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
386                                          gfp_t gfp, struct bio_set *bs)
387 {
388         if (sectors >= bio_sectors(bio))
389                 return bio;
390 
391         return bio_split(bio, sectors, gfp, bs);
392 }
393 
394 extern struct bio_set *bioset_create(unsigned int, unsigned int);
395 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
396 extern void bioset_free(struct bio_set *);
397 extern mempool_t *biovec_create_pool(int pool_entries);
398 
399 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
400 extern void bio_put(struct bio *);
401 
402 extern void __bio_clone_fast(struct bio *, struct bio *);
403 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
404 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
405 
406 extern struct bio_set *fs_bio_set;
407 
408 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
409 {
410         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
411 }
412 
413 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
414 {
415         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
416 }
417 
418 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
419 {
420         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
421 }
422 
423 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
424 {
425         return bio_clone_bioset(bio, gfp_mask, NULL);
426 
427 }
428 
429 extern void bio_endio(struct bio *, int);
430 struct request_queue;
431 extern int bio_phys_segments(struct request_queue *, struct bio *);
432 
433 extern int submit_bio_wait(int rw, struct bio *bio);
434 extern void bio_advance(struct bio *, unsigned);
435 
436 extern void bio_init(struct bio *);
437 extern void bio_reset(struct bio *);
438 void bio_chain(struct bio *, struct bio *);
439 
440 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
441 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
442                            unsigned int, unsigned int);
443 extern int bio_get_nr_vecs(struct block_device *);
444 struct rq_map_data;
445 extern struct bio *bio_map_user_iov(struct request_queue *,
446                                     const struct iov_iter *, gfp_t);
447 extern void bio_unmap_user(struct bio *);
448 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
449                                 gfp_t);
450 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
451                                  gfp_t, int);
452 extern void bio_set_pages_dirty(struct bio *bio);
453 extern void bio_check_pages_dirty(struct bio *bio);
454 
455 void generic_start_io_acct(int rw, unsigned long sectors,
456                            struct hd_struct *part);
457 void generic_end_io_acct(int rw, struct hd_struct *part,
458                          unsigned long start_time);
459 
460 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
461 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
462 #endif
463 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
464 extern void bio_flush_dcache_pages(struct bio *bi);
465 #else
466 static inline void bio_flush_dcache_pages(struct bio *bi)
467 {
468 }
469 #endif
470 
471 extern void bio_copy_data(struct bio *dst, struct bio *src);
472 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
473 
474 extern struct bio *bio_copy_user_iov(struct request_queue *,
475                                      struct rq_map_data *,
476                                      const struct iov_iter *,
477                                      gfp_t);
478 extern int bio_uncopy_user(struct bio *);
479 void zero_fill_bio(struct bio *bio);
480 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
481 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
482 extern unsigned int bvec_nr_vecs(unsigned short idx);
483 
484 #ifdef CONFIG_BLK_CGROUP
485 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
486 int bio_associate_current(struct bio *bio);
487 void bio_disassociate_task(struct bio *bio);
488 #else   /* CONFIG_BLK_CGROUP */
489 static inline int bio_associate_blkcg(struct bio *bio,
490                         struct cgroup_subsys_state *blkcg_css) { return 0; }
491 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
492 static inline void bio_disassociate_task(struct bio *bio) { }
493 #endif  /* CONFIG_BLK_CGROUP */
494 
495 #ifdef CONFIG_HIGHMEM
496 /*
497  * remember never ever reenable interrupts between a bvec_kmap_irq and
498  * bvec_kunmap_irq!
499  */
500 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
501 {
502         unsigned long addr;
503 
504         /*
505          * might not be a highmem page, but the preempt/irq count
506          * balancing is a lot nicer this way
507          */
508         local_irq_save(*flags);
509         addr = (unsigned long) kmap_atomic(bvec->bv_page);
510 
511         BUG_ON(addr & ~PAGE_MASK);
512 
513         return (char *) addr + bvec->bv_offset;
514 }
515 
516 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
517 {
518         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
519 
520         kunmap_atomic((void *) ptr);
521         local_irq_restore(*flags);
522 }
523 
524 #else
525 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
526 {
527         return page_address(bvec->bv_page) + bvec->bv_offset;
528 }
529 
530 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
531 {
532         *flags = 0;
533 }
534 #endif
535 
536 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
537                                    unsigned long *flags)
538 {
539         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
540 }
541 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
542 
543 #define bio_kmap_irq(bio, flags) \
544         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
545 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
546 
547 /*
548  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
549  *
550  * A bio_list anchors a singly-linked list of bios chained through the bi_next
551  * member of the bio.  The bio_list also caches the last list member to allow
552  * fast access to the tail.
553  */
554 struct bio_list {
555         struct bio *head;
556         struct bio *tail;
557 };
558 
559 static inline int bio_list_empty(const struct bio_list *bl)
560 {
561         return bl->head == NULL;
562 }
563 
564 static inline void bio_list_init(struct bio_list *bl)
565 {
566         bl->head = bl->tail = NULL;
567 }
568 
569 #define BIO_EMPTY_LIST  { NULL, NULL }
570 
571 #define bio_list_for_each(bio, bl) \
572         for (bio = (bl)->head; bio; bio = bio->bi_next)
573 
574 static inline unsigned bio_list_size(const struct bio_list *bl)
575 {
576         unsigned sz = 0;
577         struct bio *bio;
578 
579         bio_list_for_each(bio, bl)
580                 sz++;
581 
582         return sz;
583 }
584 
585 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
586 {
587         bio->bi_next = NULL;
588 
589         if (bl->tail)
590                 bl->tail->bi_next = bio;
591         else
592                 bl->head = bio;
593 
594         bl->tail = bio;
595 }
596 
597 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
598 {
599         bio->bi_next = bl->head;
600 
601         bl->head = bio;
602 
603         if (!bl->tail)
604                 bl->tail = bio;
605 }
606 
607 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
608 {
609         if (!bl2->head)
610                 return;
611 
612         if (bl->tail)
613                 bl->tail->bi_next = bl2->head;
614         else
615                 bl->head = bl2->head;
616 
617         bl->tail = bl2->tail;
618 }
619 
620 static inline void bio_list_merge_head(struct bio_list *bl,
621                                        struct bio_list *bl2)
622 {
623         if (!bl2->head)
624                 return;
625 
626         if (bl->head)
627                 bl2->tail->bi_next = bl->head;
628         else
629                 bl->tail = bl2->tail;
630 
631         bl->head = bl2->head;
632 }
633 
634 static inline struct bio *bio_list_peek(struct bio_list *bl)
635 {
636         return bl->head;
637 }
638 
639 static inline struct bio *bio_list_pop(struct bio_list *bl)
640 {
641         struct bio *bio = bl->head;
642 
643         if (bio) {
644                 bl->head = bl->head->bi_next;
645                 if (!bl->head)
646                         bl->tail = NULL;
647 
648                 bio->bi_next = NULL;
649         }
650 
651         return bio;
652 }
653 
654 static inline struct bio *bio_list_get(struct bio_list *bl)
655 {
656         struct bio *bio = bl->head;
657 
658         bl->head = bl->tail = NULL;
659 
660         return bio;
661 }
662 
663 /*
664  * bio_set is used to allow other portions of the IO system to
665  * allocate their own private memory pools for bio and iovec structures.
666  * These memory pools in turn all allocate from the bio_slab
667  * and the bvec_slabs[].
668  */
669 #define BIO_POOL_SIZE 2
670 #define BIOVEC_NR_POOLS 6
671 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
672 
673 struct bio_set {
674         struct kmem_cache *bio_slab;
675         unsigned int front_pad;
676 
677         mempool_t *bio_pool;
678         mempool_t *bvec_pool;
679 #if defined(CONFIG_BLK_DEV_INTEGRITY)
680         mempool_t *bio_integrity_pool;
681         mempool_t *bvec_integrity_pool;
682 #endif
683 
684         /*
685          * Deadlock avoidance for stacking block drivers: see comments in
686          * bio_alloc_bioset() for details
687          */
688         spinlock_t              rescue_lock;
689         struct bio_list         rescue_list;
690         struct work_struct      rescue_work;
691         struct workqueue_struct *rescue_workqueue;
692 };
693 
694 struct biovec_slab {
695         int nr_vecs;
696         char *name;
697         struct kmem_cache *slab;
698 };
699 
700 /*
701  * a small number of entries is fine, not going to be performance critical.
702  * basically we just need to survive
703  */
704 #define BIO_SPLIT_ENTRIES 2
705 
706 #if defined(CONFIG_BLK_DEV_INTEGRITY)
707 
708 #define bip_for_each_vec(bvl, bip, iter)                                \
709         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
710 
711 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
712         for_each_bio(_bio)                                              \
713                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
714 
715 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
716 extern void bio_integrity_free(struct bio *);
717 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
718 extern bool bio_integrity_enabled(struct bio *bio);
719 extern int bio_integrity_prep(struct bio *);
720 extern void bio_integrity_endio(struct bio *, int);
721 extern void bio_integrity_advance(struct bio *, unsigned int);
722 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
723 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
724 extern int bioset_integrity_create(struct bio_set *, int);
725 extern void bioset_integrity_free(struct bio_set *);
726 extern void bio_integrity_init(void);
727 
728 #else /* CONFIG_BLK_DEV_INTEGRITY */
729 
730 static inline void *bio_integrity(struct bio *bio)
731 {
732         return NULL;
733 }
734 
735 static inline bool bio_integrity_enabled(struct bio *bio)
736 {
737         return false;
738 }
739 
740 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
741 {
742         return 0;
743 }
744 
745 static inline void bioset_integrity_free (struct bio_set *bs)
746 {
747         return;
748 }
749 
750 static inline int bio_integrity_prep(struct bio *bio)
751 {
752         return 0;
753 }
754 
755 static inline void bio_integrity_free(struct bio *bio)
756 {
757         return;
758 }
759 
760 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
761                                       gfp_t gfp_mask)
762 {
763         return 0;
764 }
765 
766 static inline void bio_integrity_advance(struct bio *bio,
767                                          unsigned int bytes_done)
768 {
769         return;
770 }
771 
772 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
773                                       unsigned int sectors)
774 {
775         return;
776 }
777 
778 static inline void bio_integrity_init(void)
779 {
780         return;
781 }
782 
783 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
784 {
785         return false;
786 }
787 
788 #endif /* CONFIG_BLK_DEV_INTEGRITY */
789 
790 #endif /* CONFIG_BLOCK */
791 #endif /* __LINUX_BIO_H */
792 

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