xref: /openbmc/linux/include/linux/bio.h (revision f3539c12)
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 
45 #define bio_prio(bio)			(bio)->bi_ioprio
46 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
47 
48 #define bio_iter_iovec(bio, iter)				\
49 	bvec_iter_bvec((bio)->bi_io_vec, (iter))
50 
51 #define bio_iter_page(bio, iter)				\
52 	bvec_iter_page((bio)->bi_io_vec, (iter))
53 #define bio_iter_len(bio, iter)					\
54 	bvec_iter_len((bio)->bi_io_vec, (iter))
55 #define bio_iter_offset(bio, iter)				\
56 	bvec_iter_offset((bio)->bi_io_vec, (iter))
57 
58 #define bio_page(bio)		bio_iter_page((bio), (bio)->bi_iter)
59 #define bio_offset(bio)		bio_iter_offset((bio), (bio)->bi_iter)
60 #define bio_iovec(bio)		bio_iter_iovec((bio), (bio)->bi_iter)
61 
62 #define bio_multiple_segments(bio)				\
63 	((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
64 #define bio_sectors(bio)	((bio)->bi_iter.bi_size >> 9)
65 #define bio_end_sector(bio)	((bio)->bi_iter.bi_sector + bio_sectors((bio)))
66 
67 /*
68  * Check whether this bio carries any data or not. A NULL bio is allowed.
69  */
70 static inline bool bio_has_data(struct bio *bio)
71 {
72 	if (bio &&
73 	    bio->bi_iter.bi_size &&
74 	    bio_op(bio) != REQ_OP_DISCARD &&
75 	    bio_op(bio) != REQ_OP_SECURE_ERASE)
76 		return true;
77 
78 	return false;
79 }
80 
81 static inline bool bio_no_advance_iter(struct bio *bio)
82 {
83 	return bio_op(bio) == REQ_OP_DISCARD ||
84 	       bio_op(bio) == REQ_OP_SECURE_ERASE ||
85 	       bio_op(bio) == REQ_OP_WRITE_SAME;
86 }
87 
88 static inline bool bio_is_rw(struct bio *bio)
89 {
90 	if (!bio_has_data(bio))
91 		return false;
92 
93 	if (bio_no_advance_iter(bio))
94 		return false;
95 
96 	return true;
97 }
98 
99 static inline bool bio_mergeable(struct bio *bio)
100 {
101 	if (bio->bi_opf & REQ_NOMERGE_FLAGS)
102 		return false;
103 
104 	return true;
105 }
106 
107 static inline unsigned int bio_cur_bytes(struct bio *bio)
108 {
109 	if (bio_has_data(bio))
110 		return bio_iovec(bio).bv_len;
111 	else /* dataless requests such as discard */
112 		return bio->bi_iter.bi_size;
113 }
114 
115 static inline void *bio_data(struct bio *bio)
116 {
117 	if (bio_has_data(bio))
118 		return page_address(bio_page(bio)) + bio_offset(bio);
119 
120 	return NULL;
121 }
122 
123 /*
124  * will die
125  */
126 #define bio_to_phys(bio)	(page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
127 #define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
128 
129 /*
130  * queues that have highmem support enabled may still need to revert to
131  * PIO transfers occasionally and thus map high pages temporarily. For
132  * permanent PIO fall back, user is probably better off disabling highmem
133  * I/O completely on that queue (see ide-dma for example)
134  */
135 #define __bio_kmap_atomic(bio, iter)				\
136 	(kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +	\
137 		bio_iter_iovec((bio), (iter)).bv_offset)
138 
139 #define __bio_kunmap_atomic(addr)	kunmap_atomic(addr)
140 
141 /*
142  * merge helpers etc
143  */
144 
145 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
146 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
147 	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
148 
149 /*
150  * allow arch override, for eg virtualized architectures (put in asm/io.h)
151  */
152 #ifndef BIOVEC_PHYS_MERGEABLE
153 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
154 	__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
155 #endif
156 
157 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
158 	(((addr1) | (mask)) == (((addr2) - 1) | (mask)))
159 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
160 	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
161 
162 /*
163  * drivers should _never_ use the all version - the bio may have been split
164  * before it got to the driver and the driver won't own all of it
165  */
166 #define bio_for_each_segment_all(bvl, bio, i)				\
167 	for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
168 
169 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
170 				    unsigned bytes)
171 {
172 	iter->bi_sector += bytes >> 9;
173 
174 	if (bio_no_advance_iter(bio))
175 		iter->bi_size -= bytes;
176 	else
177 		bvec_iter_advance(bio->bi_io_vec, iter, bytes);
178 }
179 
180 #define __bio_for_each_segment(bvl, bio, iter, start)			\
181 	for (iter = (start);						\
182 	     (iter).bi_size &&						\
183 		((bvl = bio_iter_iovec((bio), (iter))), 1);		\
184 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
185 
186 #define bio_for_each_segment(bvl, bio, iter)				\
187 	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
188 
189 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
190 
191 static inline unsigned bio_segments(struct bio *bio)
192 {
193 	unsigned segs = 0;
194 	struct bio_vec bv;
195 	struct bvec_iter iter;
196 
197 	/*
198 	 * We special case discard/write same, because they interpret bi_size
199 	 * differently:
200 	 */
201 
202 	if (bio_op(bio) == REQ_OP_DISCARD)
203 		return 1;
204 
205 	if (bio_op(bio) == REQ_OP_SECURE_ERASE)
206 		return 1;
207 
208 	if (bio_op(bio) == REQ_OP_WRITE_SAME)
209 		return 1;
210 
211 	bio_for_each_segment(bv, bio, iter)
212 		segs++;
213 
214 	return segs;
215 }
216 
217 /*
218  * get a reference to a bio, so it won't disappear. the intended use is
219  * something like:
220  *
221  * bio_get(bio);
222  * submit_bio(rw, bio);
223  * if (bio->bi_flags ...)
224  *	do_something
225  * bio_put(bio);
226  *
227  * without the bio_get(), it could potentially complete I/O before submit_bio
228  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
229  * runs
230  */
231 static inline void bio_get(struct bio *bio)
232 {
233 	bio->bi_flags |= (1 << BIO_REFFED);
234 	smp_mb__before_atomic();
235 	atomic_inc(&bio->__bi_cnt);
236 }
237 
238 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
239 {
240 	if (count != 1) {
241 		bio->bi_flags |= (1 << BIO_REFFED);
242 		smp_mb__before_atomic();
243 	}
244 	atomic_set(&bio->__bi_cnt, count);
245 }
246 
247 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
248 {
249 	return (bio->bi_flags & (1U << bit)) != 0;
250 }
251 
252 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
253 {
254 	bio->bi_flags |= (1U << bit);
255 }
256 
257 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
258 {
259 	bio->bi_flags &= ~(1U << bit);
260 }
261 
262 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
263 {
264 	*bv = bio_iovec(bio);
265 }
266 
267 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
268 {
269 	struct bvec_iter iter = bio->bi_iter;
270 	int idx;
271 
272 	if (unlikely(!bio_multiple_segments(bio))) {
273 		*bv = bio_iovec(bio);
274 		return;
275 	}
276 
277 	bio_advance_iter(bio, &iter, iter.bi_size);
278 
279 	if (!iter.bi_bvec_done)
280 		idx = iter.bi_idx - 1;
281 	else	/* in the middle of bvec */
282 		idx = iter.bi_idx;
283 
284 	*bv = bio->bi_io_vec[idx];
285 
286 	/*
287 	 * iter.bi_bvec_done records actual length of the last bvec
288 	 * if this bio ends in the middle of one io vector
289 	 */
290 	if (iter.bi_bvec_done)
291 		bv->bv_len = iter.bi_bvec_done;
292 }
293 
294 enum bip_flags {
295 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
296 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
297 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
298 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
299 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
300 };
301 
302 /*
303  * bio integrity payload
304  */
305 struct bio_integrity_payload {
306 	struct bio		*bip_bio;	/* parent bio */
307 
308 	struct bvec_iter	bip_iter;
309 
310 	bio_end_io_t		*bip_end_io;	/* saved I/O completion fn */
311 
312 	unsigned short		bip_slab;	/* slab the bip came from */
313 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
314 	unsigned short		bip_max_vcnt;	/* integrity bio_vec slots */
315 	unsigned short		bip_flags;	/* control flags */
316 
317 	struct work_struct	bip_work;	/* I/O completion */
318 
319 	struct bio_vec		*bip_vec;
320 	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
321 };
322 
323 #if defined(CONFIG_BLK_DEV_INTEGRITY)
324 
325 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
326 {
327 	if (bio->bi_opf & REQ_INTEGRITY)
328 		return bio->bi_integrity;
329 
330 	return NULL;
331 }
332 
333 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
334 {
335 	struct bio_integrity_payload *bip = bio_integrity(bio);
336 
337 	if (bip)
338 		return bip->bip_flags & flag;
339 
340 	return false;
341 }
342 
343 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
344 {
345 	return bip->bip_iter.bi_sector;
346 }
347 
348 static inline void bip_set_seed(struct bio_integrity_payload *bip,
349 				sector_t seed)
350 {
351 	bip->bip_iter.bi_sector = seed;
352 }
353 
354 #endif /* CONFIG_BLK_DEV_INTEGRITY */
355 
356 extern void bio_trim(struct bio *bio, int offset, int size);
357 extern struct bio *bio_split(struct bio *bio, int sectors,
358 			     gfp_t gfp, struct bio_set *bs);
359 
360 /**
361  * bio_next_split - get next @sectors from a bio, splitting if necessary
362  * @bio:	bio to split
363  * @sectors:	number of sectors to split from the front of @bio
364  * @gfp:	gfp mask
365  * @bs:		bio set to allocate from
366  *
367  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
368  * than @sectors, returns the original bio unchanged.
369  */
370 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
371 					 gfp_t gfp, struct bio_set *bs)
372 {
373 	if (sectors >= bio_sectors(bio))
374 		return bio;
375 
376 	return bio_split(bio, sectors, gfp, bs);
377 }
378 
379 extern struct bio_set *bioset_create(unsigned int, unsigned int);
380 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
381 extern void bioset_free(struct bio_set *);
382 extern mempool_t *biovec_create_pool(int pool_entries);
383 
384 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
385 extern void bio_put(struct bio *);
386 
387 extern void __bio_clone_fast(struct bio *, struct bio *);
388 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
389 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
390 
391 extern struct bio_set *fs_bio_set;
392 
393 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
394 {
395 	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
396 }
397 
398 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
399 {
400 	return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
401 }
402 
403 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
404 {
405 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
406 }
407 
408 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
409 {
410 	return bio_clone_bioset(bio, gfp_mask, NULL);
411 
412 }
413 
414 extern void bio_endio(struct bio *);
415 
416 static inline void bio_io_error(struct bio *bio)
417 {
418 	bio->bi_error = -EIO;
419 	bio_endio(bio);
420 }
421 
422 struct request_queue;
423 extern int bio_phys_segments(struct request_queue *, struct bio *);
424 
425 extern int submit_bio_wait(struct bio *bio);
426 extern void bio_advance(struct bio *, unsigned);
427 
428 extern void bio_init(struct bio *);
429 extern void bio_reset(struct bio *);
430 void bio_chain(struct bio *, struct bio *);
431 
432 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
433 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
434 			   unsigned int, unsigned int);
435 struct rq_map_data;
436 extern struct bio *bio_map_user_iov(struct request_queue *,
437 				    const struct iov_iter *, gfp_t);
438 extern void bio_unmap_user(struct bio *);
439 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
440 				gfp_t);
441 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
442 				 gfp_t, int);
443 extern void bio_set_pages_dirty(struct bio *bio);
444 extern void bio_check_pages_dirty(struct bio *bio);
445 
446 void generic_start_io_acct(int rw, unsigned long sectors,
447 			   struct hd_struct *part);
448 void generic_end_io_acct(int rw, struct hd_struct *part,
449 			 unsigned long start_time);
450 
451 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
452 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
453 #endif
454 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
455 extern void bio_flush_dcache_pages(struct bio *bi);
456 #else
457 static inline void bio_flush_dcache_pages(struct bio *bi)
458 {
459 }
460 #endif
461 
462 extern void bio_copy_data(struct bio *dst, struct bio *src);
463 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
464 
465 extern struct bio *bio_copy_user_iov(struct request_queue *,
466 				     struct rq_map_data *,
467 				     const struct iov_iter *,
468 				     gfp_t);
469 extern int bio_uncopy_user(struct bio *);
470 void zero_fill_bio(struct bio *bio);
471 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
472 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
473 extern unsigned int bvec_nr_vecs(unsigned short idx);
474 
475 #ifdef CONFIG_BLK_CGROUP
476 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
477 int bio_associate_current(struct bio *bio);
478 void bio_disassociate_task(struct bio *bio);
479 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
480 #else	/* CONFIG_BLK_CGROUP */
481 static inline int bio_associate_blkcg(struct bio *bio,
482 			struct cgroup_subsys_state *blkcg_css) { return 0; }
483 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
484 static inline void bio_disassociate_task(struct bio *bio) { }
485 static inline void bio_clone_blkcg_association(struct bio *dst,
486 			struct bio *src) { }
487 #endif	/* CONFIG_BLK_CGROUP */
488 
489 #ifdef CONFIG_HIGHMEM
490 /*
491  * remember never ever reenable interrupts between a bvec_kmap_irq and
492  * bvec_kunmap_irq!
493  */
494 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
495 {
496 	unsigned long addr;
497 
498 	/*
499 	 * might not be a highmem page, but the preempt/irq count
500 	 * balancing is a lot nicer this way
501 	 */
502 	local_irq_save(*flags);
503 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
504 
505 	BUG_ON(addr & ~PAGE_MASK);
506 
507 	return (char *) addr + bvec->bv_offset;
508 }
509 
510 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
511 {
512 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
513 
514 	kunmap_atomic((void *) ptr);
515 	local_irq_restore(*flags);
516 }
517 
518 #else
519 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
520 {
521 	return page_address(bvec->bv_page) + bvec->bv_offset;
522 }
523 
524 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
525 {
526 	*flags = 0;
527 }
528 #endif
529 
530 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
531 				   unsigned long *flags)
532 {
533 	return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
534 }
535 #define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)
536 
537 #define bio_kmap_irq(bio, flags) \
538 	__bio_kmap_irq((bio), (bio)->bi_iter, (flags))
539 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
540 
541 /*
542  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
543  *
544  * A bio_list anchors a singly-linked list of bios chained through the bi_next
545  * member of the bio.  The bio_list also caches the last list member to allow
546  * fast access to the tail.
547  */
548 struct bio_list {
549 	struct bio *head;
550 	struct bio *tail;
551 };
552 
553 static inline int bio_list_empty(const struct bio_list *bl)
554 {
555 	return bl->head == NULL;
556 }
557 
558 static inline void bio_list_init(struct bio_list *bl)
559 {
560 	bl->head = bl->tail = NULL;
561 }
562 
563 #define BIO_EMPTY_LIST	{ NULL, NULL }
564 
565 #define bio_list_for_each(bio, bl) \
566 	for (bio = (bl)->head; bio; bio = bio->bi_next)
567 
568 static inline unsigned bio_list_size(const struct bio_list *bl)
569 {
570 	unsigned sz = 0;
571 	struct bio *bio;
572 
573 	bio_list_for_each(bio, bl)
574 		sz++;
575 
576 	return sz;
577 }
578 
579 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
580 {
581 	bio->bi_next = NULL;
582 
583 	if (bl->tail)
584 		bl->tail->bi_next = bio;
585 	else
586 		bl->head = bio;
587 
588 	bl->tail = bio;
589 }
590 
591 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
592 {
593 	bio->bi_next = bl->head;
594 
595 	bl->head = bio;
596 
597 	if (!bl->tail)
598 		bl->tail = bio;
599 }
600 
601 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
602 {
603 	if (!bl2->head)
604 		return;
605 
606 	if (bl->tail)
607 		bl->tail->bi_next = bl2->head;
608 	else
609 		bl->head = bl2->head;
610 
611 	bl->tail = bl2->tail;
612 }
613 
614 static inline void bio_list_merge_head(struct bio_list *bl,
615 				       struct bio_list *bl2)
616 {
617 	if (!bl2->head)
618 		return;
619 
620 	if (bl->head)
621 		bl2->tail->bi_next = bl->head;
622 	else
623 		bl->tail = bl2->tail;
624 
625 	bl->head = bl2->head;
626 }
627 
628 static inline struct bio *bio_list_peek(struct bio_list *bl)
629 {
630 	return bl->head;
631 }
632 
633 static inline struct bio *bio_list_pop(struct bio_list *bl)
634 {
635 	struct bio *bio = bl->head;
636 
637 	if (bio) {
638 		bl->head = bl->head->bi_next;
639 		if (!bl->head)
640 			bl->tail = NULL;
641 
642 		bio->bi_next = NULL;
643 	}
644 
645 	return bio;
646 }
647 
648 static inline struct bio *bio_list_get(struct bio_list *bl)
649 {
650 	struct bio *bio = bl->head;
651 
652 	bl->head = bl->tail = NULL;
653 
654 	return bio;
655 }
656 
657 /*
658  * Increment chain count for the bio. Make sure the CHAIN flag update
659  * is visible before the raised count.
660  */
661 static inline void bio_inc_remaining(struct bio *bio)
662 {
663 	bio_set_flag(bio, BIO_CHAIN);
664 	smp_mb__before_atomic();
665 	atomic_inc(&bio->__bi_remaining);
666 }
667 
668 /*
669  * bio_set is used to allow other portions of the IO system to
670  * allocate their own private memory pools for bio and iovec structures.
671  * These memory pools in turn all allocate from the bio_slab
672  * and the bvec_slabs[].
673  */
674 #define BIO_POOL_SIZE 2
675 
676 struct bio_set {
677 	struct kmem_cache *bio_slab;
678 	unsigned int front_pad;
679 
680 	mempool_t *bio_pool;
681 	mempool_t *bvec_pool;
682 #if defined(CONFIG_BLK_DEV_INTEGRITY)
683 	mempool_t *bio_integrity_pool;
684 	mempool_t *bvec_integrity_pool;
685 #endif
686 
687 	/*
688 	 * Deadlock avoidance for stacking block drivers: see comments in
689 	 * bio_alloc_bioset() for details
690 	 */
691 	spinlock_t		rescue_lock;
692 	struct bio_list		rescue_list;
693 	struct work_struct	rescue_work;
694 	struct workqueue_struct	*rescue_workqueue;
695 };
696 
697 struct biovec_slab {
698 	int nr_vecs;
699 	char *name;
700 	struct kmem_cache *slab;
701 };
702 
703 /*
704  * a small number of entries is fine, not going to be performance critical.
705  * basically we just need to survive
706  */
707 #define BIO_SPLIT_ENTRIES 2
708 
709 #if defined(CONFIG_BLK_DEV_INTEGRITY)
710 
711 #define bip_for_each_vec(bvl, bip, iter)				\
712 	for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
713 
714 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
715 	for_each_bio(_bio)						\
716 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
717 
718 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
719 extern void bio_integrity_free(struct bio *);
720 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
721 extern bool bio_integrity_enabled(struct bio *bio);
722 extern int bio_integrity_prep(struct bio *);
723 extern void bio_integrity_endio(struct bio *);
724 extern void bio_integrity_advance(struct bio *, unsigned int);
725 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
726 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
727 extern int bioset_integrity_create(struct bio_set *, int);
728 extern void bioset_integrity_free(struct bio_set *);
729 extern void bio_integrity_init(void);
730 
731 #else /* CONFIG_BLK_DEV_INTEGRITY */
732 
733 static inline void *bio_integrity(struct bio *bio)
734 {
735 	return NULL;
736 }
737 
738 static inline bool bio_integrity_enabled(struct bio *bio)
739 {
740 	return false;
741 }
742 
743 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
744 {
745 	return 0;
746 }
747 
748 static inline void bioset_integrity_free (struct bio_set *bs)
749 {
750 	return;
751 }
752 
753 static inline int bio_integrity_prep(struct bio *bio)
754 {
755 	return 0;
756 }
757 
758 static inline void bio_integrity_free(struct bio *bio)
759 {
760 	return;
761 }
762 
763 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
764 				      gfp_t gfp_mask)
765 {
766 	return 0;
767 }
768 
769 static inline void bio_integrity_advance(struct bio *bio,
770 					 unsigned int bytes_done)
771 {
772 	return;
773 }
774 
775 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
776 				      unsigned int sectors)
777 {
778 	return;
779 }
780 
781 static inline void bio_integrity_init(void)
782 {
783 	return;
784 }
785 
786 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
787 {
788 	return false;
789 }
790 
791 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
792 								unsigned int nr)
793 {
794 	return ERR_PTR(-EINVAL);
795 }
796 
797 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
798 					unsigned int len, unsigned int offset)
799 {
800 	return 0;
801 }
802 
803 #endif /* CONFIG_BLK_DEV_INTEGRITY */
804 
805 #endif /* CONFIG_BLOCK */
806 #endif /* __LINUX_BIO_H */
807