xref: /openbmc/linux/include/linux/bio.h (revision 8730046c)
1 /*
2  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  *
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public Licens
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
17  */
18 #ifndef __LINUX_BIO_H
19 #define __LINUX_BIO_H
20 
21 #include <linux/highmem.h>
22 #include <linux/mempool.h>
23 #include <linux/ioprio.h>
24 #include <linux/bug.h>
25 
26 #ifdef CONFIG_BLOCK
27 
28 #include <asm/io.h>
29 
30 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
31 #include <linux/blk_types.h>
32 
33 #define BIO_DEBUG
34 
35 #ifdef BIO_DEBUG
36 #define BIO_BUG_ON	BUG_ON
37 #else
38 #define BIO_BUG_ON
39 #endif
40 
41 #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_ZEROES:
201 		return 0;
202 	case REQ_OP_WRITE_SAME:
203 		return 1;
204 	default:
205 		break;
206 	}
207 
208 	bio_for_each_segment(bv, bio, iter)
209 		segs++;
210 
211 	return segs;
212 }
213 
214 /*
215  * get a reference to a bio, so it won't disappear. the intended use is
216  * something like:
217  *
218  * bio_get(bio);
219  * submit_bio(rw, bio);
220  * if (bio->bi_flags ...)
221  *	do_something
222  * bio_put(bio);
223  *
224  * without the bio_get(), it could potentially complete I/O before submit_bio
225  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
226  * runs
227  */
228 static inline void bio_get(struct bio *bio)
229 {
230 	bio->bi_flags |= (1 << BIO_REFFED);
231 	smp_mb__before_atomic();
232 	atomic_inc(&bio->__bi_cnt);
233 }
234 
235 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
236 {
237 	if (count != 1) {
238 		bio->bi_flags |= (1 << BIO_REFFED);
239 		smp_mb__before_atomic();
240 	}
241 	atomic_set(&bio->__bi_cnt, count);
242 }
243 
244 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
245 {
246 	return (bio->bi_flags & (1U << bit)) != 0;
247 }
248 
249 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
250 {
251 	bio->bi_flags |= (1U << bit);
252 }
253 
254 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
255 {
256 	bio->bi_flags &= ~(1U << bit);
257 }
258 
259 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
260 {
261 	*bv = bio_iovec(bio);
262 }
263 
264 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
265 {
266 	struct bvec_iter iter = bio->bi_iter;
267 	int idx;
268 
269 	if (unlikely(!bio_multiple_segments(bio))) {
270 		*bv = bio_iovec(bio);
271 		return;
272 	}
273 
274 	bio_advance_iter(bio, &iter, iter.bi_size);
275 
276 	if (!iter.bi_bvec_done)
277 		idx = iter.bi_idx - 1;
278 	else	/* in the middle of bvec */
279 		idx = iter.bi_idx;
280 
281 	*bv = bio->bi_io_vec[idx];
282 
283 	/*
284 	 * iter.bi_bvec_done records actual length of the last bvec
285 	 * if this bio ends in the middle of one io vector
286 	 */
287 	if (iter.bi_bvec_done)
288 		bv->bv_len = iter.bi_bvec_done;
289 }
290 
291 enum bip_flags {
292 	BIP_BLOCK_INTEGRITY	= 1 << 0, /* block layer owns integrity data */
293 	BIP_MAPPED_INTEGRITY	= 1 << 1, /* ref tag has been remapped */
294 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
295 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
296 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
297 };
298 
299 /*
300  * bio integrity payload
301  */
302 struct bio_integrity_payload {
303 	struct bio		*bip_bio;	/* parent bio */
304 
305 	struct bvec_iter	bip_iter;
306 
307 	bio_end_io_t		*bip_end_io;	/* saved I/O completion fn */
308 
309 	unsigned short		bip_slab;	/* slab the bip came from */
310 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
311 	unsigned short		bip_max_vcnt;	/* integrity bio_vec slots */
312 	unsigned short		bip_flags;	/* control flags */
313 
314 	struct work_struct	bip_work;	/* I/O completion */
315 
316 	struct bio_vec		*bip_vec;
317 	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
318 };
319 
320 #if defined(CONFIG_BLK_DEV_INTEGRITY)
321 
322 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
323 {
324 	if (bio->bi_opf & REQ_INTEGRITY)
325 		return bio->bi_integrity;
326 
327 	return NULL;
328 }
329 
330 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
331 {
332 	struct bio_integrity_payload *bip = bio_integrity(bio);
333 
334 	if (bip)
335 		return bip->bip_flags & flag;
336 
337 	return false;
338 }
339 
340 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
341 {
342 	return bip->bip_iter.bi_sector;
343 }
344 
345 static inline void bip_set_seed(struct bio_integrity_payload *bip,
346 				sector_t seed)
347 {
348 	bip->bip_iter.bi_sector = seed;
349 }
350 
351 #endif /* CONFIG_BLK_DEV_INTEGRITY */
352 
353 extern void bio_trim(struct bio *bio, int offset, int size);
354 extern struct bio *bio_split(struct bio *bio, int sectors,
355 			     gfp_t gfp, struct bio_set *bs);
356 
357 /**
358  * bio_next_split - get next @sectors from a bio, splitting if necessary
359  * @bio:	bio to split
360  * @sectors:	number of sectors to split from the front of @bio
361  * @gfp:	gfp mask
362  * @bs:		bio set to allocate from
363  *
364  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
365  * than @sectors, returns the original bio unchanged.
366  */
367 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
368 					 gfp_t gfp, struct bio_set *bs)
369 {
370 	if (sectors >= bio_sectors(bio))
371 		return bio;
372 
373 	return bio_split(bio, sectors, gfp, bs);
374 }
375 
376 extern struct bio_set *bioset_create(unsigned int, unsigned int);
377 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
378 extern void bioset_free(struct bio_set *);
379 extern mempool_t *biovec_create_pool(int pool_entries);
380 
381 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
382 extern void bio_put(struct bio *);
383 
384 extern void __bio_clone_fast(struct bio *, struct bio *);
385 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
386 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
387 
388 extern struct bio_set *fs_bio_set;
389 
390 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
391 {
392 	return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
393 }
394 
395 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
396 {
397 	return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
398 }
399 
400 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
401 {
402 	return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
403 }
404 
405 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
406 {
407 	return bio_clone_bioset(bio, gfp_mask, NULL);
408 
409 }
410 
411 extern blk_qc_t submit_bio(struct bio *);
412 
413 extern void bio_endio(struct bio *);
414 
415 static inline void bio_io_error(struct bio *bio)
416 {
417 	bio->bi_error = -EIO;
418 	bio_endio(bio);
419 }
420 
421 struct request_queue;
422 extern int bio_phys_segments(struct request_queue *, struct bio *);
423 
424 extern int submit_bio_wait(struct bio *bio);
425 extern void bio_advance(struct bio *, unsigned);
426 
427 extern void bio_init(struct bio *bio, struct bio_vec *table,
428 		     unsigned short max_vecs);
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 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
436 struct rq_map_data;
437 extern struct bio *bio_map_user_iov(struct request_queue *,
438 				    const struct iov_iter *, gfp_t);
439 extern void bio_unmap_user(struct bio *);
440 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
441 				gfp_t);
442 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
443 				 gfp_t, int);
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(int rw, unsigned long sectors,
448 			   struct hd_struct *part);
449 void generic_end_io_acct(int rw, struct hd_struct *part,
450 			 unsigned long start_time);
451 
452 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
453 # error	"You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
454 #endif
455 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
456 extern void bio_flush_dcache_pages(struct bio *bi);
457 #else
458 static inline void bio_flush_dcache_pages(struct bio *bi)
459 {
460 }
461 #endif
462 
463 extern void bio_copy_data(struct bio *dst, struct bio *src);
464 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
465 extern void bio_free_pages(struct bio *bio);
466 
467 extern struct bio *bio_copy_user_iov(struct request_queue *,
468 				     struct rq_map_data *,
469 				     const struct iov_iter *,
470 				     gfp_t);
471 extern int bio_uncopy_user(struct bio *);
472 void zero_fill_bio(struct bio *bio);
473 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
474 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
475 extern unsigned int bvec_nr_vecs(unsigned short idx);
476 
477 #ifdef CONFIG_BLK_CGROUP
478 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
479 int bio_associate_current(struct bio *bio);
480 void bio_disassociate_task(struct bio *bio);
481 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
482 #else	/* CONFIG_BLK_CGROUP */
483 static inline int bio_associate_blkcg(struct bio *bio,
484 			struct cgroup_subsys_state *blkcg_css) { return 0; }
485 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
486 static inline void bio_disassociate_task(struct bio *bio) { }
487 static inline void bio_clone_blkcg_association(struct bio *dst,
488 			struct bio *src) { }
489 #endif	/* CONFIG_BLK_CGROUP */
490 
491 #ifdef CONFIG_HIGHMEM
492 /*
493  * remember never ever reenable interrupts between a bvec_kmap_irq and
494  * bvec_kunmap_irq!
495  */
496 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
497 {
498 	unsigned long addr;
499 
500 	/*
501 	 * might not be a highmem page, but the preempt/irq count
502 	 * balancing is a lot nicer this way
503 	 */
504 	local_irq_save(*flags);
505 	addr = (unsigned long) kmap_atomic(bvec->bv_page);
506 
507 	BUG_ON(addr & ~PAGE_MASK);
508 
509 	return (char *) addr + bvec->bv_offset;
510 }
511 
512 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
513 {
514 	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
515 
516 	kunmap_atomic((void *) ptr);
517 	local_irq_restore(*flags);
518 }
519 
520 #else
521 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
522 {
523 	return page_address(bvec->bv_page) + bvec->bv_offset;
524 }
525 
526 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
527 {
528 	*flags = 0;
529 }
530 #endif
531 
532 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
533 				   unsigned long *flags)
534 {
535 	return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
536 }
537 #define __bio_kunmap_irq(buf, flags)	bvec_kunmap_irq(buf, flags)
538 
539 #define bio_kmap_irq(bio, flags) \
540 	__bio_kmap_irq((bio), (bio)->bi_iter, (flags))
541 #define bio_kunmap_irq(buf,flags)	__bio_kunmap_irq(buf, flags)
542 
543 /*
544  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
545  *
546  * A bio_list anchors a singly-linked list of bios chained through the bi_next
547  * member of the bio.  The bio_list also caches the last list member to allow
548  * fast access to the tail.
549  */
550 struct bio_list {
551 	struct bio *head;
552 	struct bio *tail;
553 };
554 
555 static inline int bio_list_empty(const struct bio_list *bl)
556 {
557 	return bl->head == NULL;
558 }
559 
560 static inline void bio_list_init(struct bio_list *bl)
561 {
562 	bl->head = bl->tail = NULL;
563 }
564 
565 #define BIO_EMPTY_LIST	{ NULL, NULL }
566 
567 #define bio_list_for_each(bio, bl) \
568 	for (bio = (bl)->head; bio; bio = bio->bi_next)
569 
570 static inline unsigned bio_list_size(const struct bio_list *bl)
571 {
572 	unsigned sz = 0;
573 	struct bio *bio;
574 
575 	bio_list_for_each(bio, bl)
576 		sz++;
577 
578 	return sz;
579 }
580 
581 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
582 {
583 	bio->bi_next = NULL;
584 
585 	if (bl->tail)
586 		bl->tail->bi_next = bio;
587 	else
588 		bl->head = bio;
589 
590 	bl->tail = bio;
591 }
592 
593 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
594 {
595 	bio->bi_next = bl->head;
596 
597 	bl->head = bio;
598 
599 	if (!bl->tail)
600 		bl->tail = bio;
601 }
602 
603 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
604 {
605 	if (!bl2->head)
606 		return;
607 
608 	if (bl->tail)
609 		bl->tail->bi_next = bl2->head;
610 	else
611 		bl->head = bl2->head;
612 
613 	bl->tail = bl2->tail;
614 }
615 
616 static inline void bio_list_merge_head(struct bio_list *bl,
617 				       struct bio_list *bl2)
618 {
619 	if (!bl2->head)
620 		return;
621 
622 	if (bl->head)
623 		bl2->tail->bi_next = bl->head;
624 	else
625 		bl->tail = bl2->tail;
626 
627 	bl->head = bl2->head;
628 }
629 
630 static inline struct bio *bio_list_peek(struct bio_list *bl)
631 {
632 	return bl->head;
633 }
634 
635 static inline struct bio *bio_list_pop(struct bio_list *bl)
636 {
637 	struct bio *bio = bl->head;
638 
639 	if (bio) {
640 		bl->head = bl->head->bi_next;
641 		if (!bl->head)
642 			bl->tail = NULL;
643 
644 		bio->bi_next = NULL;
645 	}
646 
647 	return bio;
648 }
649 
650 static inline struct bio *bio_list_get(struct bio_list *bl)
651 {
652 	struct bio *bio = bl->head;
653 
654 	bl->head = bl->tail = NULL;
655 
656 	return bio;
657 }
658 
659 /*
660  * Increment chain count for the bio. Make sure the CHAIN flag update
661  * is visible before the raised count.
662  */
663 static inline void bio_inc_remaining(struct bio *bio)
664 {
665 	bio_set_flag(bio, BIO_CHAIN);
666 	smp_mb__before_atomic();
667 	atomic_inc(&bio->__bi_remaining);
668 }
669 
670 /*
671  * bio_set is used to allow other portions of the IO system to
672  * allocate their own private memory pools for bio and iovec structures.
673  * These memory pools in turn all allocate from the bio_slab
674  * and the bvec_slabs[].
675  */
676 #define BIO_POOL_SIZE 2
677 
678 struct bio_set {
679 	struct kmem_cache *bio_slab;
680 	unsigned int front_pad;
681 
682 	mempool_t *bio_pool;
683 	mempool_t *bvec_pool;
684 #if defined(CONFIG_BLK_DEV_INTEGRITY)
685 	mempool_t *bio_integrity_pool;
686 	mempool_t *bvec_integrity_pool;
687 #endif
688 
689 	/*
690 	 * Deadlock avoidance for stacking block drivers: see comments in
691 	 * bio_alloc_bioset() for details
692 	 */
693 	spinlock_t		rescue_lock;
694 	struct bio_list		rescue_list;
695 	struct work_struct	rescue_work;
696 	struct workqueue_struct	*rescue_workqueue;
697 };
698 
699 struct biovec_slab {
700 	int nr_vecs;
701 	char *name;
702 	struct kmem_cache *slab;
703 };
704 
705 /*
706  * a small number of entries is fine, not going to be performance critical.
707  * basically we just need to survive
708  */
709 #define BIO_SPLIT_ENTRIES 2
710 
711 #if defined(CONFIG_BLK_DEV_INTEGRITY)
712 
713 #define bip_for_each_vec(bvl, bip, iter)				\
714 	for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
715 
716 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
717 	for_each_bio(_bio)						\
718 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
719 
720 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
721 extern void bio_integrity_free(struct bio *);
722 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
723 extern bool bio_integrity_enabled(struct bio *bio);
724 extern int bio_integrity_prep(struct bio *);
725 extern void bio_integrity_endio(struct bio *);
726 extern void bio_integrity_advance(struct bio *, unsigned int);
727 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
728 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
729 extern int bioset_integrity_create(struct bio_set *, int);
730 extern void bioset_integrity_free(struct bio_set *);
731 extern void bio_integrity_init(void);
732 
733 #else /* CONFIG_BLK_DEV_INTEGRITY */
734 
735 static inline void *bio_integrity(struct bio *bio)
736 {
737 	return NULL;
738 }
739 
740 static inline bool bio_integrity_enabled(struct bio *bio)
741 {
742 	return false;
743 }
744 
745 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
746 {
747 	return 0;
748 }
749 
750 static inline void bioset_integrity_free (struct bio_set *bs)
751 {
752 	return;
753 }
754 
755 static inline int bio_integrity_prep(struct bio *bio)
756 {
757 	return 0;
758 }
759 
760 static inline void bio_integrity_free(struct bio *bio)
761 {
762 	return;
763 }
764 
765 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
766 				      gfp_t gfp_mask)
767 {
768 	return 0;
769 }
770 
771 static inline void bio_integrity_advance(struct bio *bio,
772 					 unsigned int bytes_done)
773 {
774 	return;
775 }
776 
777 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
778 				      unsigned int sectors)
779 {
780 	return;
781 }
782 
783 static inline void bio_integrity_init(void)
784 {
785 	return;
786 }
787 
788 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
789 {
790 	return false;
791 }
792 
793 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
794 								unsigned int nr)
795 {
796 	return ERR_PTR(-EINVAL);
797 }
798 
799 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
800 					unsigned int len, unsigned int offset)
801 {
802 	return 0;
803 }
804 
805 #endif /* CONFIG_BLK_DEV_INTEGRITY */
806 
807 #endif /* CONFIG_BLOCK */
808 #endif /* __LINUX_BIO_H */
809