xref: /openbmc/linux/include/linux/bio.h (revision bd4af432)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
4  */
5 #ifndef __LINUX_BIO_H
6 #define __LINUX_BIO_H
7 
8 #include <linux/highmem.h>
9 #include <linux/mempool.h>
10 #include <linux/ioprio.h>
11 
12 #ifdef CONFIG_BLOCK
13 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
14 #include <linux/blk_types.h>
15 
16 #define BIO_DEBUG
17 
18 #ifdef BIO_DEBUG
19 #define BIO_BUG_ON	BUG_ON
20 #else
21 #define BIO_BUG_ON
22 #endif
23 
24 #define BIO_MAX_PAGES		256
25 
26 #define bio_prio(bio)			(bio)->bi_ioprio
27 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
28 
29 #define bio_iter_iovec(bio, iter)				\
30 	bvec_iter_bvec((bio)->bi_io_vec, (iter))
31 
32 #define bio_iter_page(bio, iter)				\
33 	bvec_iter_page((bio)->bi_io_vec, (iter))
34 #define bio_iter_len(bio, iter)					\
35 	bvec_iter_len((bio)->bi_io_vec, (iter))
36 #define bio_iter_offset(bio, iter)				\
37 	bvec_iter_offset((bio)->bi_io_vec, (iter))
38 
39 #define bio_page(bio)		bio_iter_page((bio), (bio)->bi_iter)
40 #define bio_offset(bio)		bio_iter_offset((bio), (bio)->bi_iter)
41 #define bio_iovec(bio)		bio_iter_iovec((bio), (bio)->bi_iter)
42 
43 #define bio_multiple_segments(bio)				\
44 	((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
45 
46 #define bvec_iter_sectors(iter)	((iter).bi_size >> 9)
47 #define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
48 
49 #define bio_sectors(bio)	bvec_iter_sectors((bio)->bi_iter)
50 #define bio_end_sector(bio)	bvec_iter_end_sector((bio)->bi_iter)
51 
52 /*
53  * Return the data direction, READ or WRITE.
54  */
55 #define bio_data_dir(bio) \
56 	(op_is_write(bio_op(bio)) ? WRITE : READ)
57 
58 /*
59  * Check whether this bio carries any data or not. A NULL bio is allowed.
60  */
61 static inline bool bio_has_data(struct bio *bio)
62 {
63 	if (bio &&
64 	    bio->bi_iter.bi_size &&
65 	    bio_op(bio) != REQ_OP_DISCARD &&
66 	    bio_op(bio) != REQ_OP_SECURE_ERASE &&
67 	    bio_op(bio) != REQ_OP_WRITE_ZEROES)
68 		return true;
69 
70 	return false;
71 }
72 
73 static inline bool bio_no_advance_iter(struct bio *bio)
74 {
75 	return bio_op(bio) == REQ_OP_DISCARD ||
76 	       bio_op(bio) == REQ_OP_SECURE_ERASE ||
77 	       bio_op(bio) == REQ_OP_WRITE_SAME ||
78 	       bio_op(bio) == REQ_OP_WRITE_ZEROES;
79 }
80 
81 static inline bool bio_mergeable(struct bio *bio)
82 {
83 	if (bio->bi_opf & REQ_NOMERGE_FLAGS)
84 		return false;
85 
86 	return true;
87 }
88 
89 static inline unsigned int bio_cur_bytes(struct bio *bio)
90 {
91 	if (bio_has_data(bio))
92 		return bio_iovec(bio).bv_len;
93 	else /* dataless requests such as discard */
94 		return bio->bi_iter.bi_size;
95 }
96 
97 static inline void *bio_data(struct bio *bio)
98 {
99 	if (bio_has_data(bio))
100 		return page_address(bio_page(bio)) + bio_offset(bio);
101 
102 	return NULL;
103 }
104 
105 /**
106  * bio_full - check if the bio is full
107  * @bio:	bio to check
108  * @len:	length of one segment to be added
109  *
110  * Return true if @bio is full and one segment with @len bytes can't be
111  * added to the bio, otherwise return false
112  */
113 static inline bool bio_full(struct bio *bio, unsigned len)
114 {
115 	if (bio->bi_vcnt >= bio->bi_max_vecs)
116 		return true;
117 
118 	if (bio->bi_iter.bi_size > UINT_MAX - len)
119 		return true;
120 
121 	return false;
122 }
123 
124 static inline bool bio_next_segment(const struct bio *bio,
125 				    struct bvec_iter_all *iter)
126 {
127 	if (iter->idx >= bio->bi_vcnt)
128 		return false;
129 
130 	bvec_advance(&bio->bi_io_vec[iter->idx], iter);
131 	return true;
132 }
133 
134 /*
135  * drivers should _never_ use the all version - the bio may have been split
136  * before it got to the driver and the driver won't own all of it
137  */
138 #define bio_for_each_segment_all(bvl, bio, iter) \
139 	for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
140 
141 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
142 				    unsigned bytes)
143 {
144 	iter->bi_sector += bytes >> 9;
145 
146 	if (bio_no_advance_iter(bio))
147 		iter->bi_size -= bytes;
148 	else
149 		bvec_iter_advance(bio->bi_io_vec, iter, bytes);
150 		/* TODO: It is reasonable to complete bio with error here. */
151 }
152 
153 #define __bio_for_each_segment(bvl, bio, iter, start)			\
154 	for (iter = (start);						\
155 	     (iter).bi_size &&						\
156 		((bvl = bio_iter_iovec((bio), (iter))), 1);		\
157 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
158 
159 #define bio_for_each_segment(bvl, bio, iter)				\
160 	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
161 
162 #define __bio_for_each_bvec(bvl, bio, iter, start)		\
163 	for (iter = (start);						\
164 	     (iter).bi_size &&						\
165 		((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
166 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
167 
168 /* iterate over multi-page bvec */
169 #define bio_for_each_bvec(bvl, bio, iter)			\
170 	__bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
171 
172 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
173 
174 static inline unsigned bio_segments(struct bio *bio)
175 {
176 	unsigned segs = 0;
177 	struct bio_vec bv;
178 	struct bvec_iter iter;
179 
180 	/*
181 	 * We special case discard/write same/write zeroes, because they
182 	 * interpret bi_size differently:
183 	 */
184 
185 	switch (bio_op(bio)) {
186 	case REQ_OP_DISCARD:
187 	case REQ_OP_SECURE_ERASE:
188 	case REQ_OP_WRITE_ZEROES:
189 		return 0;
190 	case REQ_OP_WRITE_SAME:
191 		return 1;
192 	default:
193 		break;
194 	}
195 
196 	bio_for_each_segment(bv, bio, iter)
197 		segs++;
198 
199 	return segs;
200 }
201 
202 /*
203  * get a reference to a bio, so it won't disappear. the intended use is
204  * something like:
205  *
206  * bio_get(bio);
207  * submit_bio(rw, bio);
208  * if (bio->bi_flags ...)
209  *	do_something
210  * bio_put(bio);
211  *
212  * without the bio_get(), it could potentially complete I/O before submit_bio
213  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
214  * runs
215  */
216 static inline void bio_get(struct bio *bio)
217 {
218 	bio->bi_flags |= (1 << BIO_REFFED);
219 	smp_mb__before_atomic();
220 	atomic_inc(&bio->__bi_cnt);
221 }
222 
223 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
224 {
225 	if (count != 1) {
226 		bio->bi_flags |= (1 << BIO_REFFED);
227 		smp_mb();
228 	}
229 	atomic_set(&bio->__bi_cnt, count);
230 }
231 
232 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
233 {
234 	return (bio->bi_flags & (1U << bit)) != 0;
235 }
236 
237 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
238 {
239 	bio->bi_flags |= (1U << bit);
240 }
241 
242 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
243 {
244 	bio->bi_flags &= ~(1U << bit);
245 }
246 
247 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
248 {
249 	*bv = bio_iovec(bio);
250 }
251 
252 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
253 {
254 	struct bvec_iter iter = bio->bi_iter;
255 	int idx;
256 
257 	if (unlikely(!bio_multiple_segments(bio))) {
258 		*bv = bio_iovec(bio);
259 		return;
260 	}
261 
262 	bio_advance_iter(bio, &iter, iter.bi_size);
263 
264 	if (!iter.bi_bvec_done)
265 		idx = iter.bi_idx - 1;
266 	else	/* in the middle of bvec */
267 		idx = iter.bi_idx;
268 
269 	*bv = bio->bi_io_vec[idx];
270 
271 	/*
272 	 * iter.bi_bvec_done records actual length of the last bvec
273 	 * if this bio ends in the middle of one io vector
274 	 */
275 	if (iter.bi_bvec_done)
276 		bv->bv_len = iter.bi_bvec_done;
277 }
278 
279 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
280 {
281 	WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
282 	return bio->bi_io_vec;
283 }
284 
285 static inline struct page *bio_first_page_all(struct bio *bio)
286 {
287 	return bio_first_bvec_all(bio)->bv_page;
288 }
289 
290 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
291 {
292 	WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
293 	return &bio->bi_io_vec[bio->bi_vcnt - 1];
294 }
295 
296 enum bip_flags {
297 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
298 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
299 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
300 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
301 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
302 };
303 
304 /*
305  * bio integrity payload
306  */
307 struct bio_integrity_payload {
308 	struct bio		*bip_bio;	/* parent bio */
309 
310 	struct bvec_iter	bip_iter;
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 bvec_iter	bio_iter;	/* for rewinding parent bio */
318 
319 	struct work_struct	bip_work;	/* I/O completion */
320 
321 	struct bio_vec		*bip_vec;
322 	struct bio_vec		bip_inline_vecs[];/* embedded bvec array */
323 };
324 
325 #if defined(CONFIG_BLK_DEV_INTEGRITY)
326 
327 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
328 {
329 	if (bio->bi_opf & REQ_INTEGRITY)
330 		return bio->bi_integrity;
331 
332 	return NULL;
333 }
334 
335 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
336 {
337 	struct bio_integrity_payload *bip = bio_integrity(bio);
338 
339 	if (bip)
340 		return bip->bip_flags & flag;
341 
342 	return false;
343 }
344 
345 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
346 {
347 	return bip->bip_iter.bi_sector;
348 }
349 
350 static inline void bip_set_seed(struct bio_integrity_payload *bip,
351 				sector_t seed)
352 {
353 	bip->bip_iter.bi_sector = seed;
354 }
355 
356 #endif /* CONFIG_BLK_DEV_INTEGRITY */
357 
358 extern void bio_trim(struct bio *bio, int offset, int size);
359 extern struct bio *bio_split(struct bio *bio, int sectors,
360 			     gfp_t gfp, struct bio_set *bs);
361 
362 /**
363  * bio_next_split - get next @sectors from a bio, splitting if necessary
364  * @bio:	bio to split
365  * @sectors:	number of sectors to split from the front of @bio
366  * @gfp:	gfp mask
367  * @bs:		bio set to allocate from
368  *
369  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
370  * than @sectors, returns the original bio unchanged.
371  */
372 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
373 					 gfp_t gfp, struct bio_set *bs)
374 {
375 	if (sectors >= bio_sectors(bio))
376 		return bio;
377 
378 	return bio_split(bio, sectors, gfp, bs);
379 }
380 
381 enum {
382 	BIOSET_NEED_BVECS = BIT(0),
383 	BIOSET_NEED_RESCUER = BIT(1),
384 };
385 extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
386 extern void bioset_exit(struct bio_set *);
387 extern int biovec_init_pool(mempool_t *pool, int pool_entries);
388 extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
389 
390 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
391 extern void bio_put(struct bio *);
392 
393 extern void __bio_clone_fast(struct bio *, struct bio *);
394 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
395 
396 extern struct bio_set fs_bio_set;
397 
398 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
399 {
400 	return bio_alloc_bioset(gfp_mask, nr_iovecs, &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 extern blk_qc_t submit_bio(struct bio *);
409 
410 extern void bio_endio(struct bio *);
411 
412 static inline void bio_io_error(struct bio *bio)
413 {
414 	bio->bi_status = BLK_STS_IOERR;
415 	bio_endio(bio);
416 }
417 
418 static inline void bio_wouldblock_error(struct bio *bio)
419 {
420 	bio->bi_status = BLK_STS_AGAIN;
421 	bio_endio(bio);
422 }
423 
424 struct request_queue;
425 
426 extern int submit_bio_wait(struct bio *bio);
427 extern void bio_advance(struct bio *, unsigned);
428 
429 extern void bio_init(struct bio *bio, struct bio_vec *table,
430 		     unsigned short max_vecs);
431 extern void bio_uninit(struct bio *);
432 extern void bio_reset(struct bio *);
433 void bio_chain(struct bio *, struct bio *);
434 
435 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
436 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
437 			   unsigned int, unsigned int);
438 bool __bio_try_merge_page(struct bio *bio, struct page *page,
439 		unsigned int len, unsigned int off, bool *same_page);
440 void __bio_add_page(struct bio *bio, struct page *page,
441 		unsigned int len, unsigned int off);
442 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
443 void bio_release_pages(struct bio *bio, bool mark_dirty);
444 extern void bio_set_pages_dirty(struct bio *bio);
445 extern void bio_check_pages_dirty(struct bio *bio);
446 
447 void generic_start_io_acct(struct request_queue *q, int op,
448 				unsigned long sectors, struct hd_struct *part);
449 void generic_end_io_acct(struct request_queue *q, int op,
450 				struct hd_struct *part,
451 				unsigned long start_time);
452 
453 extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
454 			       struct bio *src, struct bvec_iter *src_iter);
455 extern void bio_copy_data(struct bio *dst, struct bio *src);
456 extern void bio_list_copy_data(struct bio *dst, struct bio *src);
457 extern void bio_free_pages(struct bio *bio);
458 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
459 void bio_truncate(struct bio *bio, unsigned new_size);
460 void guard_bio_eod(struct bio *bio);
461 
462 static inline void zero_fill_bio(struct bio *bio)
463 {
464 	zero_fill_bio_iter(bio, bio->bi_iter);
465 }
466 
467 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
468 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
469 extern unsigned int bvec_nr_vecs(unsigned short idx);
470 extern const char *bio_devname(struct bio *bio, char *buffer);
471 
472 #define bio_set_dev(bio, bdev) 			\
473 do {						\
474 	if ((bio)->bi_disk != (bdev)->bd_disk)	\
475 		bio_clear_flag(bio, BIO_THROTTLED);\
476 	(bio)->bi_disk = (bdev)->bd_disk;	\
477 	(bio)->bi_partno = (bdev)->bd_partno;	\
478 	bio_associate_blkg(bio);		\
479 } while (0)
480 
481 #define bio_copy_dev(dst, src)			\
482 do {						\
483 	(dst)->bi_disk = (src)->bi_disk;	\
484 	(dst)->bi_partno = (src)->bi_partno;	\
485 	bio_clone_blkg_association(dst, src);	\
486 } while (0)
487 
488 #define bio_dev(bio) \
489 	disk_devt((bio)->bi_disk)
490 
491 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
492 void bio_associate_blkg_from_page(struct bio *bio, struct page *page);
493 #else
494 static inline void bio_associate_blkg_from_page(struct bio *bio,
495 						struct page *page) { }
496 #endif
497 
498 #ifdef CONFIG_BLK_CGROUP
499 void bio_disassociate_blkg(struct bio *bio);
500 void bio_associate_blkg(struct bio *bio);
501 void bio_associate_blkg_from_css(struct bio *bio,
502 				 struct cgroup_subsys_state *css);
503 void bio_clone_blkg_association(struct bio *dst, struct bio *src);
504 #else	/* CONFIG_BLK_CGROUP */
505 static inline void bio_disassociate_blkg(struct bio *bio) { }
506 static inline void bio_associate_blkg(struct bio *bio) { }
507 static inline void bio_associate_blkg_from_css(struct bio *bio,
508 					       struct cgroup_subsys_state *css)
509 { }
510 static inline void bio_clone_blkg_association(struct bio *dst,
511 					      struct bio *src) { }
512 #endif	/* CONFIG_BLK_CGROUP */
513 
514 #ifdef CONFIG_HIGHMEM
515 /*
516  * remember never ever reenable interrupts between a bvec_kmap_irq and
517  * bvec_kunmap_irq!
518  */
519 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
520 {
521 	unsigned long addr;
522 
523 	/*
524 	 * might not be a highmem page, but the preempt/irq count
525 	 * balancing is a lot nicer this way
526 	 */
527 	local_irq_save(*flags);
528 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
529 
530 	BUG_ON(addr & ~PAGE_MASK);
531 
532 	return (char *) addr + bvec->bv_offset;
533 }
534 
535 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
536 {
537 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
538 
539 	kunmap_atomic((void *) ptr);
540 	local_irq_restore(*flags);
541 }
542 
543 #else
544 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
545 {
546 	return page_address(bvec->bv_page) + bvec->bv_offset;
547 }
548 
549 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
550 {
551 	*flags = 0;
552 }
553 #endif
554 
555 /*
556  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
557  *
558  * A bio_list anchors a singly-linked list of bios chained through the bi_next
559  * member of the bio.  The bio_list also caches the last list member to allow
560  * fast access to the tail.
561  */
562 struct bio_list {
563 	struct bio *head;
564 	struct bio *tail;
565 };
566 
567 static inline int bio_list_empty(const struct bio_list *bl)
568 {
569 	return bl->head == NULL;
570 }
571 
572 static inline void bio_list_init(struct bio_list *bl)
573 {
574 	bl->head = bl->tail = NULL;
575 }
576 
577 #define BIO_EMPTY_LIST	{ NULL, NULL }
578 
579 #define bio_list_for_each(bio, bl) \
580 	for (bio = (bl)->head; bio; bio = bio->bi_next)
581 
582 static inline unsigned bio_list_size(const struct bio_list *bl)
583 {
584 	unsigned sz = 0;
585 	struct bio *bio;
586 
587 	bio_list_for_each(bio, bl)
588 		sz++;
589 
590 	return sz;
591 }
592 
593 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
594 {
595 	bio->bi_next = NULL;
596 
597 	if (bl->tail)
598 		bl->tail->bi_next = bio;
599 	else
600 		bl->head = bio;
601 
602 	bl->tail = bio;
603 }
604 
605 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
606 {
607 	bio->bi_next = bl->head;
608 
609 	bl->head = bio;
610 
611 	if (!bl->tail)
612 		bl->tail = bio;
613 }
614 
615 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
616 {
617 	if (!bl2->head)
618 		return;
619 
620 	if (bl->tail)
621 		bl->tail->bi_next = bl2->head;
622 	else
623 		bl->head = bl2->head;
624 
625 	bl->tail = bl2->tail;
626 }
627 
628 static inline void bio_list_merge_head(struct bio_list *bl,
629 				       struct bio_list *bl2)
630 {
631 	if (!bl2->head)
632 		return;
633 
634 	if (bl->head)
635 		bl2->tail->bi_next = bl->head;
636 	else
637 		bl->tail = bl2->tail;
638 
639 	bl->head = bl2->head;
640 }
641 
642 static inline struct bio *bio_list_peek(struct bio_list *bl)
643 {
644 	return bl->head;
645 }
646 
647 static inline struct bio *bio_list_pop(struct bio_list *bl)
648 {
649 	struct bio *bio = bl->head;
650 
651 	if (bio) {
652 		bl->head = bl->head->bi_next;
653 		if (!bl->head)
654 			bl->tail = NULL;
655 
656 		bio->bi_next = NULL;
657 	}
658 
659 	return bio;
660 }
661 
662 static inline struct bio *bio_list_get(struct bio_list *bl)
663 {
664 	struct bio *bio = bl->head;
665 
666 	bl->head = bl->tail = NULL;
667 
668 	return bio;
669 }
670 
671 /*
672  * Increment chain count for the bio. Make sure the CHAIN flag update
673  * is visible before the raised count.
674  */
675 static inline void bio_inc_remaining(struct bio *bio)
676 {
677 	bio_set_flag(bio, BIO_CHAIN);
678 	smp_mb__before_atomic();
679 	atomic_inc(&bio->__bi_remaining);
680 }
681 
682 /*
683  * bio_set is used to allow other portions of the IO system to
684  * allocate their own private memory pools for bio and iovec structures.
685  * These memory pools in turn all allocate from the bio_slab
686  * and the bvec_slabs[].
687  */
688 #define BIO_POOL_SIZE 2
689 
690 struct bio_set {
691 	struct kmem_cache *bio_slab;
692 	unsigned int front_pad;
693 
694 	mempool_t bio_pool;
695 	mempool_t bvec_pool;
696 #if defined(CONFIG_BLK_DEV_INTEGRITY)
697 	mempool_t bio_integrity_pool;
698 	mempool_t bvec_integrity_pool;
699 #endif
700 
701 	/*
702 	 * Deadlock avoidance for stacking block drivers: see comments in
703 	 * bio_alloc_bioset() for details
704 	 */
705 	spinlock_t		rescue_lock;
706 	struct bio_list		rescue_list;
707 	struct work_struct	rescue_work;
708 	struct workqueue_struct	*rescue_workqueue;
709 };
710 
711 struct biovec_slab {
712 	int nr_vecs;
713 	char *name;
714 	struct kmem_cache *slab;
715 };
716 
717 static inline bool bioset_initialized(struct bio_set *bs)
718 {
719 	return bs->bio_slab != NULL;
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 int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
739 extern bool bio_integrity_prep(struct bio *);
740 extern void bio_integrity_advance(struct bio *, unsigned int);
741 extern void bio_integrity_trim(struct bio *);
742 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
743 extern int bioset_integrity_create(struct bio_set *, int);
744 extern void bioset_integrity_free(struct bio_set *);
745 extern void bio_integrity_init(void);
746 
747 #else /* CONFIG_BLK_DEV_INTEGRITY */
748 
749 static inline void *bio_integrity(struct bio *bio)
750 {
751 	return NULL;
752 }
753 
754 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
755 {
756 	return 0;
757 }
758 
759 static inline void bioset_integrity_free (struct bio_set *bs)
760 {
761 	return;
762 }
763 
764 static inline bool bio_integrity_prep(struct bio *bio)
765 {
766 	return true;
767 }
768 
769 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
770 				      gfp_t gfp_mask)
771 {
772 	return 0;
773 }
774 
775 static inline void bio_integrity_advance(struct bio *bio,
776 					 unsigned int bytes_done)
777 {
778 	return;
779 }
780 
781 static inline void bio_integrity_trim(struct bio *bio)
782 {
783 	return;
784 }
785 
786 static inline void bio_integrity_init(void)
787 {
788 	return;
789 }
790 
791 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
792 {
793 	return false;
794 }
795 
796 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
797 								unsigned int nr)
798 {
799 	return ERR_PTR(-EINVAL);
800 }
801 
802 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
803 					unsigned int len, unsigned int offset)
804 {
805 	return 0;
806 }
807 
808 #endif /* CONFIG_BLK_DEV_INTEGRITY */
809 
810 /*
811  * Mark a bio as polled. Note that for async polled IO, the caller must
812  * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
813  * We cannot block waiting for requests on polled IO, as those completions
814  * must be found by the caller. This is different than IRQ driven IO, where
815  * it's safe to wait for IO to complete.
816  */
817 static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
818 {
819 	bio->bi_opf |= REQ_HIPRI;
820 	if (!is_sync_kiocb(kiocb))
821 		bio->bi_opf |= REQ_NOWAIT;
822 }
823 
824 #endif /* CONFIG_BLOCK */
825 #endif /* __LINUX_BIO_H */
826