xref: /linux-6.15/include/linux/bio.h (revision 6ea76f33)
1 /*
2  * Copyright (C) 2001 Jens Axboe <[email protected]>
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 #define BIO_MAX_PAGES		256
42 
43 #define bio_prio(bio)			(bio)->bi_ioprio
44 #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
45 
46 #define bio_iter_iovec(bio, iter)				\
47 	bvec_iter_bvec((bio)->bi_io_vec, (iter))
48 
49 #define bio_iter_page(bio, iter)				\
50 	bvec_iter_page((bio)->bi_io_vec, (iter))
51 #define bio_iter_len(bio, iter)					\
52 	bvec_iter_len((bio)->bi_io_vec, (iter))
53 #define bio_iter_offset(bio, iter)				\
54 	bvec_iter_offset((bio)->bi_io_vec, (iter))
55 
56 #define bio_page(bio)		bio_iter_page((bio), (bio)->bi_iter)
57 #define bio_offset(bio)		bio_iter_offset((bio), (bio)->bi_iter)
58 #define bio_iovec(bio)		bio_iter_iovec((bio), (bio)->bi_iter)
59 
60 #define bio_multiple_segments(bio)				\
61 	((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
62 #define bio_sectors(bio)	((bio)->bi_iter.bi_size >> 9)
63 #define bio_end_sector(bio)	((bio)->bi_iter.bi_sector + bio_sectors((bio)))
64 
65 /*
66  * Return the data direction, READ or WRITE.
67  */
68 #define bio_data_dir(bio) \
69 	(op_is_write(bio_op(bio)) ? WRITE : READ)
70 
71 /*
72  * Check whether this bio carries any data or not. A NULL bio is allowed.
73  */
74 static inline bool bio_has_data(struct bio *bio)
75 {
76 	if (bio &&
77 	    bio->bi_iter.bi_size &&
78 	    bio_op(bio) != REQ_OP_DISCARD &&
79 	    bio_op(bio) != REQ_OP_SECURE_ERASE &&
80 	    bio_op(bio) != REQ_OP_WRITE_ZEROES)
81 		return true;
82 
83 	return false;
84 }
85 
86 static inline bool bio_no_advance_iter(struct bio *bio)
87 {
88 	return bio_op(bio) == REQ_OP_DISCARD ||
89 	       bio_op(bio) == REQ_OP_SECURE_ERASE ||
90 	       bio_op(bio) == REQ_OP_WRITE_SAME ||
91 	       bio_op(bio) == REQ_OP_WRITE_ZEROES;
92 }
93 
94 static inline bool bio_mergeable(struct bio *bio)
95 {
96 	if (bio->bi_opf & REQ_NOMERGE_FLAGS)
97 		return false;
98 
99 	return true;
100 }
101 
102 static inline unsigned int bio_cur_bytes(struct bio *bio)
103 {
104 	if (bio_has_data(bio))
105 		return bio_iovec(bio).bv_len;
106 	else /* dataless requests such as discard */
107 		return bio->bi_iter.bi_size;
108 }
109 
110 static inline void *bio_data(struct bio *bio)
111 {
112 	if (bio_has_data(bio))
113 		return page_address(bio_page(bio)) + bio_offset(bio);
114 
115 	return NULL;
116 }
117 
118 /*
119  * will die
120  */
121 #define bio_to_phys(bio)	(page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
122 #define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
123 
124 /*
125  * queues that have highmem support enabled may still need to revert to
126  * PIO transfers occasionally and thus map high pages temporarily. For
127  * permanent PIO fall back, user is probably better off disabling highmem
128  * I/O completely on that queue (see ide-dma for example)
129  */
130 #define __bio_kmap_atomic(bio, iter)				\
131 	(kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +	\
132 		bio_iter_iovec((bio), (iter)).bv_offset)
133 
134 #define __bio_kunmap_atomic(addr)	kunmap_atomic(addr)
135 
136 /*
137  * merge helpers etc
138  */
139 
140 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
141 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
142 	((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
143 
144 /*
145  * allow arch override, for eg virtualized architectures (put in asm/io.h)
146  */
147 #ifndef BIOVEC_PHYS_MERGEABLE
148 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)	\
149 	__BIOVEC_PHYS_MERGEABLE(vec1, vec2)
150 #endif
151 
152 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
153 	(((addr1) | (mask)) == (((addr2) - 1) | (mask)))
154 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
155 	__BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
156 
157 /*
158  * drivers should _never_ use the all version - the bio may have been split
159  * before it got to the driver and the driver won't own all of it
160  */
161 #define bio_for_each_segment_all(bvl, bio, i)				\
162 	for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
163 
164 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
165 				    unsigned bytes)
166 {
167 	iter->bi_sector += bytes >> 9;
168 
169 	if (bio_no_advance_iter(bio))
170 		iter->bi_size -= bytes;
171 	else
172 		bvec_iter_advance(bio->bi_io_vec, iter, bytes);
173 }
174 
175 #define __bio_for_each_segment(bvl, bio, iter, start)			\
176 	for (iter = (start);						\
177 	     (iter).bi_size &&						\
178 		((bvl = bio_iter_iovec((bio), (iter))), 1);		\
179 	     bio_advance_iter((bio), &(iter), (bvl).bv_len))
180 
181 #define bio_for_each_segment(bvl, bio, iter)				\
182 	__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
183 
184 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
185 
186 static inline unsigned bio_segments(struct bio *bio)
187 {
188 	unsigned segs = 0;
189 	struct bio_vec bv;
190 	struct bvec_iter iter;
191 
192 	/*
193 	 * We special case discard/write same/write zeroes, because they
194 	 * interpret bi_size differently:
195 	 */
196 
197 	switch (bio_op(bio)) {
198 	case REQ_OP_DISCARD:
199 	case REQ_OP_SECURE_ERASE:
200 	case REQ_OP_WRITE_SAME:
201 	case REQ_OP_WRITE_ZEROES:
202 		return 1;
203 	default:
204 		break;
205 	}
206 
207 	bio_for_each_segment(bv, bio, iter)
208 		segs++;
209 
210 	return segs;
211 }
212 
213 /*
214  * get a reference to a bio, so it won't disappear. the intended use is
215  * something like:
216  *
217  * bio_get(bio);
218  * submit_bio(rw, bio);
219  * if (bio->bi_flags ...)
220  *	do_something
221  * bio_put(bio);
222  *
223  * without the bio_get(), it could potentially complete I/O before submit_bio
224  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
225  * runs
226  */
227 static inline void bio_get(struct bio *bio)
228 {
229 	bio->bi_flags |= (1 << BIO_REFFED);
230 	smp_mb__before_atomic();
231 	atomic_inc(&bio->__bi_cnt);
232 }
233 
234 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
235 {
236 	if (count != 1) {
237 		bio->bi_flags |= (1 << BIO_REFFED);
238 		smp_mb__before_atomic();
239 	}
240 	atomic_set(&bio->__bi_cnt, count);
241 }
242 
243 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
244 {
245 	return (bio->bi_flags & (1U << bit)) != 0;
246 }
247 
248 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
249 {
250 	bio->bi_flags |= (1U << bit);
251 }
252 
253 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
254 {
255 	bio->bi_flags &= ~(1U << bit);
256 }
257 
258 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
259 {
260 	*bv = bio_iovec(bio);
261 }
262 
263 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
264 {
265 	struct bvec_iter iter = bio->bi_iter;
266 	int idx;
267 
268 	if (unlikely(!bio_multiple_segments(bio))) {
269 		*bv = bio_iovec(bio);
270 		return;
271 	}
272 
273 	bio_advance_iter(bio, &iter, iter.bi_size);
274 
275 	if (!iter.bi_bvec_done)
276 		idx = iter.bi_idx - 1;
277 	else	/* in the middle of bvec */
278 		idx = iter.bi_idx;
279 
280 	*bv = bio->bi_io_vec[idx];
281 
282 	/*
283 	 * iter.bi_bvec_done records actual length of the last bvec
284 	 * if this bio ends in the middle of one io vector
285 	 */
286 	if (iter.bi_bvec_done)
287 		bv->bv_len = iter.bi_bvec_done;
288 }
289 
290 enum bip_flags {
291 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
292 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
293 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
294 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
295 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
296 };
297 
298 /*
299  * bio integrity payload
300  */
301 struct bio_integrity_payload {
302 	struct bio		*bip_bio;	/* parent bio */
303 
304 	struct bvec_iter	bip_iter;
305 
306 	bio_end_io_t		*bip_end_io;	/* saved I/O completion fn */
307 
308 	unsigned short		bip_slab;	/* slab the bip came from */
309 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
310 	unsigned short		bip_max_vcnt;	/* integrity bio_vec slots */
311 	unsigned short		bip_flags;	/* control flags */
312 
313 	struct work_struct	bip_work;	/* I/O completion */
314 
315 	struct bio_vec		*bip_vec;
316 	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
317 };
318 
319 #if defined(CONFIG_BLK_DEV_INTEGRITY)
320 
321 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
322 {
323 	if (bio->bi_opf & REQ_INTEGRITY)
324 		return bio->bi_integrity;
325 
326 	return NULL;
327 }
328 
329 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
330 {
331 	struct bio_integrity_payload *bip = bio_integrity(bio);
332 
333 	if (bip)
334 		return bip->bip_flags & flag;
335 
336 	return false;
337 }
338 
339 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
340 {
341 	return bip->bip_iter.bi_sector;
342 }
343 
344 static inline void bip_set_seed(struct bio_integrity_payload *bip,
345 				sector_t seed)
346 {
347 	bip->bip_iter.bi_sector = seed;
348 }
349 
350 #endif /* CONFIG_BLK_DEV_INTEGRITY */
351 
352 extern void bio_trim(struct bio *bio, int offset, int size);
353 extern struct bio *bio_split(struct bio *bio, int sectors,
354 			     gfp_t gfp, struct bio_set *bs);
355 
356 /**
357  * bio_next_split - get next @sectors from a bio, splitting if necessary
358  * @bio:	bio to split
359  * @sectors:	number of sectors to split from the front of @bio
360  * @gfp:	gfp mask
361  * @bs:		bio set to allocate from
362  *
363  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
364  * than @sectors, returns the original bio unchanged.
365  */
366 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
367 					 gfp_t gfp, struct bio_set *bs)
368 {
369 	if (sectors >= bio_sectors(bio))
370 		return bio;
371 
372 	return bio_split(bio, sectors, gfp, bs);
373 }
374 
375 extern struct bio_set *bioset_create(unsigned int, unsigned int);
376 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
377 extern void bioset_free(struct bio_set *);
378 extern mempool_t *biovec_create_pool(int pool_entries);
379 
380 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
381 extern void bio_put(struct bio *);
382 
383 extern void __bio_clone_fast(struct bio *, struct bio *);
384 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
385 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
386 
387 extern struct bio_set *fs_bio_set;
388 
389 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
390 {
391 	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
392 }
393 
394 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
395 {
396 	return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
397 }
398 
399 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
400 {
401 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
402 }
403 
404 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
405 {
406 	return bio_clone_bioset(bio, gfp_mask, NULL);
407 
408 }
409 
410 extern blk_qc_t submit_bio(struct bio *);
411 
412 extern void bio_endio(struct bio *);
413 
414 static inline void bio_io_error(struct bio *bio)
415 {
416 	bio->bi_error = -EIO;
417 	bio_endio(bio);
418 }
419 
420 struct request_queue;
421 extern int bio_phys_segments(struct request_queue *, struct bio *);
422 
423 extern int submit_bio_wait(struct bio *bio);
424 extern void bio_advance(struct bio *, unsigned);
425 
426 extern void bio_init(struct bio *bio, struct bio_vec *table,
427 		     unsigned short max_vecs);
428 extern void bio_reset(struct bio *);
429 void bio_chain(struct bio *, struct bio *);
430 
431 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
432 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
433 			   unsigned int, unsigned int);
434 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
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 extern void bio_free_pages(struct bio *bio);
465 
466 extern struct bio *bio_copy_user_iov(struct request_queue *,
467 				     struct rq_map_data *,
468 				     const struct iov_iter *,
469 				     gfp_t);
470 extern int bio_uncopy_user(struct bio *);
471 void zero_fill_bio(struct bio *bio);
472 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
473 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
474 extern unsigned int bvec_nr_vecs(unsigned short idx);
475 
476 #ifdef CONFIG_BLK_CGROUP
477 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
478 int bio_associate_current(struct bio *bio);
479 void bio_disassociate_task(struct bio *bio);
480 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
481 #else	/* CONFIG_BLK_CGROUP */
482 static inline int bio_associate_blkcg(struct bio *bio,
483 			struct cgroup_subsys_state *blkcg_css) { return 0; }
484 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
485 static inline void bio_disassociate_task(struct bio *bio) { }
486 static inline void bio_clone_blkcg_association(struct bio *dst,
487 			struct bio *src) { }
488 #endif	/* CONFIG_BLK_CGROUP */
489 
490 #ifdef CONFIG_HIGHMEM
491 /*
492  * remember never ever reenable interrupts between a bvec_kmap_irq and
493  * bvec_kunmap_irq!
494  */
495 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
496 {
497 	unsigned long addr;
498 
499 	/*
500 	 * might not be a highmem page, but the preempt/irq count
501 	 * balancing is a lot nicer this way
502 	 */
503 	local_irq_save(*flags);
504 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
505 
506 	BUG_ON(addr & ~PAGE_MASK);
507 
508 	return (char *) addr + bvec->bv_offset;
509 }
510 
511 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
512 {
513 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
514 
515 	kunmap_atomic((void *) ptr);
516 	local_irq_restore(*flags);
517 }
518 
519 #else
520 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
521 {
522 	return page_address(bvec->bv_page) + bvec->bv_offset;
523 }
524 
525 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
526 {
527 	*flags = 0;
528 }
529 #endif
530 
531 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
532 				   unsigned long *flags)
533 {
534 	return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
535 }
536 #define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)
537 
538 #define bio_kmap_irq(bio, flags) \
539 	__bio_kmap_irq((bio), (bio)->bi_iter, (flags))
540 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
541 
542 /*
543  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
544  *
545  * A bio_list anchors a singly-linked list of bios chained through the bi_next
546  * member of the bio.  The bio_list also caches the last list member to allow
547  * fast access to the tail.
548  */
549 struct bio_list {
550 	struct bio *head;
551 	struct bio *tail;
552 };
553 
554 static inline int bio_list_empty(const struct bio_list *bl)
555 {
556 	return bl->head == NULL;
557 }
558 
559 static inline void bio_list_init(struct bio_list *bl)
560 {
561 	bl->head = bl->tail = NULL;
562 }
563 
564 #define BIO_EMPTY_LIST	{ NULL, NULL }
565 
566 #define bio_list_for_each(bio, bl) \
567 	for (bio = (bl)->head; bio; bio = bio->bi_next)
568 
569 static inline unsigned bio_list_size(const struct bio_list *bl)
570 {
571 	unsigned sz = 0;
572 	struct bio *bio;
573 
574 	bio_list_for_each(bio, bl)
575 		sz++;
576 
577 	return sz;
578 }
579 
580 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
581 {
582 	bio->bi_next = NULL;
583 
584 	if (bl->tail)
585 		bl->tail->bi_next = bio;
586 	else
587 		bl->head = bio;
588 
589 	bl->tail = bio;
590 }
591 
592 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
593 {
594 	bio->bi_next = bl->head;
595 
596 	bl->head = bio;
597 
598 	if (!bl->tail)
599 		bl->tail = bio;
600 }
601 
602 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
603 {
604 	if (!bl2->head)
605 		return;
606 
607 	if (bl->tail)
608 		bl->tail->bi_next = bl2->head;
609 	else
610 		bl->head = bl2->head;
611 
612 	bl->tail = bl2->tail;
613 }
614 
615 static inline void bio_list_merge_head(struct bio_list *bl,
616 				       struct bio_list *bl2)
617 {
618 	if (!bl2->head)
619 		return;
620 
621 	if (bl->head)
622 		bl2->tail->bi_next = bl->head;
623 	else
624 		bl->tail = bl2->tail;
625 
626 	bl->head = bl2->head;
627 }
628 
629 static inline struct bio *bio_list_peek(struct bio_list *bl)
630 {
631 	return bl->head;
632 }
633 
634 static inline struct bio *bio_list_pop(struct bio_list *bl)
635 {
636 	struct bio *bio = bl->head;
637 
638 	if (bio) {
639 		bl->head = bl->head->bi_next;
640 		if (!bl->head)
641 			bl->tail = NULL;
642 
643 		bio->bi_next = NULL;
644 	}
645 
646 	return bio;
647 }
648 
649 static inline struct bio *bio_list_get(struct bio_list *bl)
650 {
651 	struct bio *bio = bl->head;
652 
653 	bl->head = bl->tail = NULL;
654 
655 	return bio;
656 }
657 
658 /*
659  * Increment chain count for the bio. Make sure the CHAIN flag update
660  * is visible before the raised count.
661  */
662 static inline void bio_inc_remaining(struct bio *bio)
663 {
664 	bio_set_flag(bio, BIO_CHAIN);
665 	smp_mb__before_atomic();
666 	atomic_inc(&bio->__bi_remaining);
667 }
668 
669 /*
670  * bio_set is used to allow other portions of the IO system to
671  * allocate their own private memory pools for bio and iovec structures.
672  * These memory pools in turn all allocate from the bio_slab
673  * and the bvec_slabs[].
674  */
675 #define BIO_POOL_SIZE 2
676 
677 struct bio_set {
678 	struct kmem_cache *bio_slab;
679 	unsigned int front_pad;
680 
681 	mempool_t *bio_pool;
682 	mempool_t *bvec_pool;
683 #if defined(CONFIG_BLK_DEV_INTEGRITY)
684 	mempool_t *bio_integrity_pool;
685 	mempool_t *bvec_integrity_pool;
686 #endif
687 
688 	/*
689 	 * Deadlock avoidance for stacking block drivers: see comments in
690 	 * bio_alloc_bioset() for details
691 	 */
692 	spinlock_t		rescue_lock;
693 	struct bio_list		rescue_list;
694 	struct work_struct	rescue_work;
695 	struct workqueue_struct	*rescue_workqueue;
696 };
697 
698 struct biovec_slab {
699 	int nr_vecs;
700 	char *name;
701 	struct kmem_cache *slab;
702 };
703 
704 /*
705  * a small number of entries is fine, not going to be performance critical.
706  * basically we just need to survive
707  */
708 #define BIO_SPLIT_ENTRIES 2
709 
710 #if defined(CONFIG_BLK_DEV_INTEGRITY)
711 
712 #define bip_for_each_vec(bvl, bip, iter)				\
713 	for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
714 
715 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
716 	for_each_bio(_bio)						\
717 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
718 
719 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
720 extern void bio_integrity_free(struct bio *);
721 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
722 extern bool bio_integrity_enabled(struct bio *bio);
723 extern int bio_integrity_prep(struct bio *);
724 extern void bio_integrity_endio(struct bio *);
725 extern void bio_integrity_advance(struct bio *, unsigned int);
726 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
727 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
728 extern int bioset_integrity_create(struct bio_set *, int);
729 extern void bioset_integrity_free(struct bio_set *);
730 extern void bio_integrity_init(void);
731 
732 #else /* CONFIG_BLK_DEV_INTEGRITY */
733 
734 static inline void *bio_integrity(struct bio *bio)
735 {
736 	return NULL;
737 }
738 
739 static inline bool bio_integrity_enabled(struct bio *bio)
740 {
741 	return false;
742 }
743 
744 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
745 {
746 	return 0;
747 }
748 
749 static inline void bioset_integrity_free (struct bio_set *bs)
750 {
751 	return;
752 }
753 
754 static inline int bio_integrity_prep(struct bio *bio)
755 {
756 	return 0;
757 }
758 
759 static inline void bio_integrity_free(struct bio *bio)
760 {
761 	return;
762 }
763 
764 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
765 				      gfp_t gfp_mask)
766 {
767 	return 0;
768 }
769 
770 static inline void bio_integrity_advance(struct bio *bio,
771 					 unsigned int bytes_done)
772 {
773 	return;
774 }
775 
776 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
777 				      unsigned int sectors)
778 {
779 	return;
780 }
781 
782 static inline void bio_integrity_init(void)
783 {
784 	return;
785 }
786 
787 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
788 {
789 	return false;
790 }
791 
792 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
793 								unsigned int nr)
794 {
795 	return ERR_PTR(-EINVAL);
796 }
797 
798 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
799 					unsigned int len, unsigned int offset)
800 {
801 	return 0;
802 }
803 
804 #endif /* CONFIG_BLK_DEV_INTEGRITY */
805 
806 #endif /* CONFIG_BLOCK */
807 #endif /* __LINUX_BIO_H */
808